EFFECTS OF NORTH AMERICAN GINSENG (Panax quinquefolius Le)

ON POSTPR4NDIAL GLYCEMIA IN NORRlAL HUMANS

Vernon Yut Yu Koo

A thesis submitted in conformity with the requirements for the degree of M.Sc.

Graduate Department of Nutritional Sciences University of Toronto

O Copyright by Vernon Yut Yu Koo 1997

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Ei?Fli;CrI'S OF NNOKTH AMERICAN GINSENG (Panax quinquefolius L.)

ON POSTPRANDIAL GLYCEMIA IN NORMAL HUMANS

Master of Science, 1997 Vernon Yut Yu Koo

Graduate Department of Nutritional Sciences University of Toronto

ABSTRACT

To investigate the effects of North Arnerican ginseng (Panax quinquefolius L.)

powder on reducing postprandial glycemia, a glucose challenge of 25 g carbohydrate was

used. Capillary blood was collected at fasting, 15, 30, 45, 60, and 90 minutes afier initial

consumption of glucose challenge.

Ginseng powder (3 g, 6g and 9 g) with glucose challenge, had no significant effect

on blood glucose when compared to glucose alone in healthy individuals (4 males, 4

females). However, when 3 g and 6 g of ginseng powder were ingested 40 or 80 minutes

pnor to glucose dnnk, lower glycemic responses (4 males, 2 females, p < 0.05) were

observed. Lower glycemic response also resulted fiom 9 g Panm quinquefolzus L.

ingested at either 40 minutes (p < 0.01), 80 minutes (p < 0.01), or 120 minutes (p < 0.05)

prior to glucose challenge. This glycemic response was not dose dependent.

It was concluded that Panax quinquefolius L. lowers postprandial glycemia at

levels of 3 g, 6 g, 9 g, and possibly at lower doses, when taken pior to glucose challenge.

In loving memory of my mother, Marie

iii

First, 1 would like to thank my supervisor, Dr. V. Vuksan, for his support and

encouragement. Without his insightful supervision and encouragement, this work would

not have been accomplished. To Dr. T.M.S. Wolever, your invaluable guidance and

suggestions were greatly appreciated. 1 would also like to thank Dr. T. Francis for his

continued support and assistance throughout my program. Special thanks to Dr. A.V.

Rao for being on my Advisory Cornmittee, Drs. D.J.A. Jenkins and S.C. Cunnane for

serving on my Examination Cornmittee, and Dr. T. Heim for being my Appraiser. 1 am

also grateful to Dr. L.U. Thompson for al1 her guidance over the years.

1 am indebted to my fnends who graciously participated in my research

experiments. Without their cornmitment, this study would never have been completed.

Sincere thanks to George Yeung for al1 his encouragement, advice and statistical help, and

Evelyn and Brenda for al1 their help and fun during my studies. 1 am also grateful to the

staff of the graduate department, in particular, Brenda Rak, for keeping me up to date.

Thanks to Atkins Farm Limited and Chai-Na-Ta Corporation for their generous

contribution of ginseng capsules and research information.

Finally, rny deepest thanks to my farnily for their unconditional love and support.

To my father and Auntie Phyllis, your patience and care are greatly appreciated. To Tina

and Clarence, thanks for putting up with me even when 1 was mistrated. To Christina,

thanks for being inexhaustibly loving and supportive throughout.

ABSTRACT ...................................................................................................................

ACKNOWlLEDGMENTS ............................................................................................

......................................................................................................... LIST OF TABLES

LIST OF FIGURES ........................................................................................................

AEIBREVIATIONS ........................................................................................................

CHAPTER 1 . Introduction and Literature Review 1.1 Introduction ............................................................................................ 1.2 Literature Review

1.2.1 History of Ginseng ....................................................................... 1.2.1 . 1 Description ............................................................................ 1.2.1 -2 North American ginseng (Panax quinquefolius L.)

...................................................................................... trade .................... 1.2.1.3 Chinese Perception on North American ginseng

.................................. 1 -2.1 -4 History of North American ginseng use 1.2.1.5 Oriental ginseng: a traditional perspective ...............................

................................... 1 -2.1 -6 Oriental ginseng: a modem perspective ......................................................... 1.2.2 Varieties of the Genus Panax

1.2.3 Active Components in Ginseng ..................................................... .............................................. 1.2 -3.1 Ginseng saponins: ginsenosides

1.2.3.2 Other active ginseng components: polysaccharides, polypeptides, flavonoids ..........................................................

1.2.4 An Overview of the Pharrnacological Effects of Ginseng ................. 1 .2.4.1 Ginseng as an adaptogen ........................................................ 1.2 .4.2 Ginsenosides R,,, and %, ........................................................ 1.2.4.3 Ginseng polysaccharides and peptides ..................................... 1.2.4.4 A biologically active ginseng peptide, a carboxylic acid

and an adenosine ..................................................................... ............................................................................ 1.2.4.5 Human trials

1.2.4.5.1 Adverse effects of ginseng ............................................. .................................................... 1.2.5 Hypoglycemic effects of ginseng

........................................................................ 1.2.5.1 Animal studies ................................................................. 1.2.5.1 . 1 Ginsenosides

1.2.5.1.2 Water (DPG-series) and methanolic (EPG-series) extracts of P . ginseng ..................................................

............ 1.2.5.1.3 Ginseng polysaccharides: glycans and panaxans

Page

. . 11

... 111

... V l l l

ix

X

. . . . . u

Introduction .......................................................................................... 62 Aim .......................................................................................................... 62 Materials and Methods ........................................................................... 62 4.3.1 Composition of glucose challenge and North Amencan ginseng ..... 62 4.3.2 Subject recruitment and profile ................................................... 63 4.3.3 Experimental design .................................................................... 63

................................. 4.3.4 Study procedure and blood sarnple collection 64 4.3.5 Blood glucose analysis .............................................................. 64 4.3.6 Statistical analysis ........................................................................... 65

4.4 ResuIts ....................................................................................................... 65 4.5 Discussion ............................................................................................ 74

CHAPTER 5 . General Discussion and Conclusions 5.1 GeneraI discussion and fbture research ....................................................... 77

.............................................................................................. 5.2 Conclusion 81

APPENDIX ....................................................................................................................... 95

vii

LIST OF TABLES

Page

Table 1.1 Common ginsenosides of Panax ginseng C.A. Meyer and Panax quinquefolius L ..................................................................................... 5

Table 1.2 Nutrient profiles of P . quinquefolius and P . ginseng ............................... 6

Table 1.3 The pharmacological activities of ginseng ............................................... 12

Table 1.4 Yield of Chinese ginseng in China in 1985 .............................................. 13

. . ...................................................................... Table 1.5 Varietles of Panax species 13

............................................................................. Table 1.6 Types of ginsenosides 15

Table 1.7 Ginsenoside contents in different parts of the ginseng plant ..................... 15

Table 1.8 Cornparison of ginsenoside contents of 2-9 year old ginseng roots ......... 18

Table 2.1 Subj ect profile ................................................................................ 42

Table 2.2 Blood glucose concentrations at specific time points. change in blood glucose peak and incremental areas under the curve (AUC) ................... 47

Table 3.1 Subject profile ...................................................................................... 54

Table 3.2 Blood glucose concentrations at specific time points. change in blood glucose peak and incremental areas under the curve (AUC) ................. 58

Table 4.1 Subject profile ..................................................................................... 67

Table 4.2 Two-way ANOVA of the mean differences in AUC among North Amencan ginseng powder. administration tirne. dose and time-dose interaction ............................................................................................ 69

viii

LIST OF FIGURES

Page

Fig. 1 .1 Chemical structures of different ginsenosides ............................................. 17

Fig. 2.1 Effect of North American ginseng taken together with a glucose challenge postprandial glycemic response (n=8) ......................................................... 45

Fig. 2.2 Incremental area under glycemic response curve: North American ginseng taken together with a glucose challenge (n=8) ............................................. 46

Fig. 3.1 Experimental design.. .............................................................. 52

Fig. 3.2 Incremental area under glycemic response curve: North American ginseng taken pnor to a glucose challenge (n=7) ...................................................... 57

Fig. 3.2 Effect of North American ginseng on postprandial blood glucose when taken prior to a glucose challenge (n=7) .................................................... 59

Fig. 4.1 Incremental area under glycemic response curve: 3 g, 6 g, 9 g of North Amencan ginseng powder taken at -40, -80, -120 minutes before a glucose challenge (n=6) ........................................................................... 68

Fig. 4.2 Percent reduction in AUC with different time and dose of North Arnerican ginseng powder administration (n=6) ......................................... 70

Fig. 4.3 Effects of 3 g North Amencan ginseng on postprandial blood glucose ....... when taken at 40,80,120 minutes prior to a glucose challenge (n=6). 7 1

Fig. 4.4 Effects of 6 g North American ginseng on postprandial blood glucose when taken at 40,80, 120 minutes p i o r to a glucose challenge (n=6) ........ 72

Fig. 4.5 Effects of 9 g North Arnerican ginseng on postprandial blood glucose when taken at 40,80, 120 minutes prior to a glucose challenge (n=6). ....... 73

Y0

AUC

BMI

DIOL

Fig

g

GS

IDDM

kg

min

mL

mrnoVL

NDDM

P. ginseng

P. japonicus

P. quinquefolius

S E

T . CHO

TCM

TRIOL

ABBREVIATIONS

Percent

Incremental blood glucose area under curve

Body mass index

Protopanaxadiol

Figure

Grams

Ginsenosides

Insulin-dependent diabetes mellitus

Kilograrns

Minutes

Milli-Litre

Milli-mole per Litre

Non-insulin dependent diabetes mellitus

Panax ginseng C.A. Meyer

Panax japonicus C.A. Meyer

Panax quinquefolius L.

Standard error of mean

Total carbohydrate

Traditionai Chinese medicine

Pro topanaxatriol

CHAPTER ONE

INTRODUCTION

AND

LITERATURE REVIEW

1.1 Introduction

The value of ginseng in promoting overall body health has long been recognized by

the Chinese, who daim to have been using ginseng for 5,000 years [Bloomfield, 19871.

The first known reference appeared in a manuscript from the third century BC, suggesting

that there exists a very long history of ginseng by humans consumption [Bloomfield,

19871. In fact, it was recorded in the first officia1 Chinese pharmacopoeia, Shen Nung Pen

Tsao, published almost 2,000 years ago. However, Shen Nung Pen Tsao was later revised

in fifih century AD and few additions were made which included using ginseng to treat

thirst and poly~ria due to diabetes, to reduce swelling and inflammation, and to increase

memory [Bloomfield, 19871. Despite its long history of medicinal use, ginseng health

beneficial claims are generally based upon anecdotal evidence. It has only been over the

past 20 years or so that some of the many claims are examined scientifically.

Ginseng is the common name of mainly two species of P a n a herbs, belonging to

the family of Araliaceae [Li and Li, 19731. North Arnerican ginseng is botanically known

as Panax quinquefolius L. (P. quinquefolius), while the more extensively studied root,

Chinese or Korean ginseng, is called either Panax schinseng Nees or Panax ginseng C.A.

Meyer (P. ginseng) [Fulder, 19931. The latter name is the more commonly used name for

Oriental ginseng today.

There are various compounds which are believed to be biologically active in the

P u n a species. Triterpenoid glycosides or saponins termed ginsenosides (GS) by Japanese

more studied ginseng components. Chemical analysis shows that both P. quinquefolius

and P. ginseng contain similar types of GS with the only difference being their respective

quantities (Table 1.1). In addition, they also have very comparable nutrient profiles (Table

1.2). Other active constituents include polysaccharides, some of which are termed

panaxans; peptides, a carboxylic acid, adenosine, and flavonoids [Konno et al., 1984;

Tomoda et al., 1984; Konno et al., 1985; Oshima et al., 1985; Zhu et al., 1989; Yang et

al., 1990; Yang and Wang, 19911. However, these compounds have only been confirrned

in Oriental ginseng.

It has been reported numerous times that ginseng components extracted fiom P.

ginseng have hypoglycemic activity in diabetic rodents [Kimura et al., 1981 a; Kimura et

al., 1981b; Kimura and Suzuki, 1985; Waki et al., 1982; Yokozawa et al., 1985; Yang et

al., 1990; Yang and Wang, 1991; Wang et al., 1990a; 1990bl However, the attributes of

ginseng that impact diabetic control in humans are not very well elucidated. Nevertheless,

recent findings by Sotaniemi et al. [1995] indicate that Oriental ginseng extract may be a

beneficial therapeutic adjunct in the management of non-insulin dependent diabetes

mellitus (NIDDM).

Since P. quinquefolius and P. ginseng have similar nutrient profiles, contain

several commonly considered active constituents in common, and Oriental ginseng

components have been demonstrated to be beneficial in diabetic humans and animals, it is

hypothesized that North American ginseng also possesses similar physiological activities

as its Asian cousin. Furthemore, the majority of ginseng research has been conducted on

- - - . A Y u - - - - - - . . - - - - - - 7 -- -- ----

purpose of this study to investigate the efficacy of P. quinquefollis powder ground from

ginseng root hair in lowering postprandial glycemia in humans. Since the dose and

method of administration have not been specified, the results from this study allow for the

determination of the optimal time and dose of administration of North American ginseng.

In addition, the results aIso give light to designing fùrther clinical studies with NIDDM

patients.

Table 1.1 Common Ginsenosides of Panax ginseng C.A. Meyer and Panax

quinquefolius L. '

Type P. ginseng (%) P. quinquefolius (%)

Protopanaxadiol

%i 0.37

%2 0.18

Rb3 0.0 1

% 0.13

O. 13

Protopanaxatriol

R, 0.20

Rd 0.2 1

R@ 0.02

Oleanolic acid

& 0.04

' Sprecher, 1987

Table 1.2 Nutrient Profiles of P. quinquefolius and P. ginseng

Types of Ginseng (per 100g)

P. quinquefolius ' P. ginseng 2

Energy (kcal) 371.2 345.4

T. CHO (g) 67 59

1 Samples supplied by Chai-Na-Ta Corp. and Atkins Farm Ltd. [JR Laboratories Inc., BC, 1997; Industrial Lab of Canada Inc., Ont., 19971 Samples suppIied by Atkins Farm Ltd. [Industrial Lab of Canada Inc., Ont., 19971

1.2.1 History of ginseng

1.2.1.1 Descri~tion

The term, ginseng, is often applied to two Panax species of the Araliaceae family;

Panax quinquefolius L. and Panax ginseng C.A. Meyer [Li and Li, 19731. While Panax

is derived from the Greek word, pan-axos, which literally means all-healing [Owen, 1980;

Fulder, 19931, ginseng rneans 'essence of the earth in the form of a man' [Graham, 19661.

North American ginseng is botanically known as Panax quinquefolius L. (P.

quinquefolius), where L denotes Linnaeus who named the plant. Oriental ginseng

(Chinese or Korean ginseng), on the other hand, was originally named Panax schinseng

Nees by Nees van Esenbeck which was later changed to Pana ginseng C.A. Meyer (P.

ginseng) by Car1 Anton Meyer in 1842 [Fulder, 19931. Today, the Oriental variety is

commonly referred to as Panax ginseng C.A. Meyer.

1.2.1.2 North American pinsenp (Panax quinquefolius L.) trade

P. quinquefolius is native to the nch, rocky, shaded, cool slopes of eastern North

Arnerica, from Quebec to Manitoba of Canada, south to northern Florida, Alabama, and

Oklahoma of the United States [Foster, 19931. Ginseng roots are herbaceous perennials

which have historically been used as a medicinal plant and a trading commodity by al1

native populations in the areas where it was grown [Oliver, 19901.

North Arnerican ginseng (P. quinquefolius) was first discovered in Quebec in 1704

by Michael Sarrasin, the King's Physician to Canada [Hellyer, 19841. The root was later

found again by Father Lafitau, a Jesuit Missionary, near Sault Ste Louis, Quebec in 171 5.

North Arnerican ginseng root was first exported fiom Canada to China by Father Jartoux

[Goldstein, 19751. By 17703, it was recorded that an average of 140,000 pounds ginseng

roots native to North America was exported each year [Foster, 19911. However, near the

turn of the eighteenth and nineteenth centuries, the early substantial profit gained fi-om

trading North Amencan ginseng with China resulted in large quantity of ginseng being

over-harvested and improperly dried in a short period of time [Hellyer, 19841. As a result,

the roots were shipped in such bad condition that it becarne unacceptable to the Chinese

which led to an enormous decline in ginseng trade with China. Exports continued to

decrease as wild ginseng became scarce with the possibility of extinction [Hellyer, 19841.

This situation prompted protective rneasures from the United States government and in

1890 Ontario government adopted the guidelines and prohibited ginseng gathering

between January and September [HelIyer, 19841.

Cultivation of North American ginseng was first attempted in 1890 by George

Stanton at Fabius, New York by transplanting wild ginseng. Soon after this, many

pamphlets were published to provide information on the techniques of growing and drying

ginseng roots [Hellyer, 19841. However, the ginseng industry suffered yet another fa11

during the depression in 1929. It was not until 1940 before export resumed [Hellyer,

19841. Today, P. qguinquefolius has established itself as a major Canadian cash crop

[Thomas, 19961. In 1995, there were approximately 250 ginseng growers producing 2.1

million pounds of dried ginseng root, valued at $40 a pound. The total crop vaIue was

$84 million. The major market for the crop remains Asia [Thomas, 19961.

1.2.1.3 Chinese perception on North American ginseng

Chinese are the greatest ginseng consumers in the world [Schreiner, 19951. They

favour P. quinquefolius for several reasons. First, when the North Amencan root was

initially exported to China, wild P. ginseng had already become extremely scarce. Asians

believe that United States manufactured or produced goods to be of superior quality. The

taste of P. quinquefolius is sweeter than its Asian variety. In addition, P. quinquefolzus

and P. ginseng are considered to possess distinct rnedicinal properties. P. quinquefolius is

considered more yin in TCM which means that it is good to reduce heat for cooling of the

respiratory or digestive systems. P. ginseng, on the other hand, is more yang and is a

heat-raising or stimulating tonic for the blood or circulatory system. As a result, P.

quinquefolius is preferred by Asians as it is a cold or mild tonic that will reduce " heat " in

the system, while acting as a general tonic.

1.2.1.4 History of North American ins sen^ use

The use of P. quinquefolius by native groups was not very well documented.

However, it was one of the five most important medicines among the Seneca Indians,

primarily used by the elderly. Crow Indians used it to induce childbirth without suffering

[Goldstein, 19751. The Oklahoma Seminole used the root to cure nosebleed and treat

shortness of breath [Howard, 19841. Penobscots drank the water extract of the root to

increase fertility in women [Speck, 191 51. Although Ojibwe had not been observed to use

the root, they harvested it for sale.

1.2.1.5 Oriental pinsene: a traditional ~erspective

Chinese or Korean ginseng (P. gznseng) is the most popular Panax species and has

been investigated substantially more than its North American cousin. This variety of

ginseng has been used for 5,000 years in the Orient as a tonic, prophylactic agent and

'restorative' [Goldstein, 1975; Hu, 1977; Bloomfield, 19871. In fact, it has been recorded

in the first Chinese pharmacopoeia, Shen Nung Pen Tsao, published alrnost 2,000 years

ago that P. ginseng 'soothes base emotions, safeguards the soul, drives out fear, expels

evil influences, brightens the eye, opens up the heart, increases the spirit, and if taken over

a long period of tirne, prolongs life' [Bloomfield, 19871. In traditional Chinese medicine

(TCM), this explanation indicates that ginseng affects liver and kidney functions, heart and

blood circulation, and treats diseases associated with exposure to "cold" or yin conditions,

such as body aches and pains, muscular contraction, diarrhea, nausea, indigestion, and

influenza [Bloomfield, 19871. However, Shen Nung Pen Tsao, was later revised in fifth

century AD by T'ao Hung-ching. Additional health conditions were attributed to Oriental

ginseng, including treatment of thirst and polyuria due to diabetes, reducing swelling and

inflammation, and increasing memory capacity [Bloomfield, 19871.

In 1552 AD, a famous herbalist, Li Shih-chen (1 5 18-1593), compiled al1 the

knowledge contained in thousand of volumes of herbal knowledge in China into a 52-

volume pharmacopoeia called Pen Tsao Kang Mu [Bloomfiled, 19871 in which ginseng

was described in detail [Li et al., 19731. This collection was completed by Li's son afler

his death and was published for the first time in 1578. In fact, it is still in print today and

ingredients used in medical treatments - herbs, roots, minerais, and animal products - but

also over 8,000 prescriptions [Bloomfield, 19871.

1.2.1.6 Oriental ginsenp: a modern ~ e r s ~ e c t i v e

Due of its long history of use, P. ginseng has been the focus of most ginseng

scientific investigations. As a consequence, Oriental ginseng is the most studied Panax

species. Over the past 20 years, many of the traditional claims associated with this root

have been studied scientifically. Many scientists worldwide have confirmed some of its

attributes in animals (Table 1.3). In addition, there is also a rapidly increasing demand for

ginseng which has warranted special efforts on the development of ginseng cultivation in

China [Liu and Xiao, 19921. This leads to substantial improvement in the quality and

quantity of ginseng produced. The total natiional yield of ginseng in 1985 was recorded as

1560.9 tons in China (Table 1.4) [Yu, 19871.

1.2.2 Varieties of the Penus Panax

Several Panax species are known to exist (Table 1.5) [Barna, 1985; Liu and Xiao,

19921 based on their place of origin. There are also other plants which are similar to the

Panax species in appearance but are, in fact, botanically different despite belonging to the

same family of Araliaceae. One of the well-known examples of this is Siberian ginseng or

Eleutherococcus senticosus [Hou, 1977; Phillipson and Anderson, 1984; Bahrke

Table 1.3 The Pharmacological Activities of Ginseng -- -

Protection against radiation and liver toxicities '4

Modulation of cardiovascular system '" Decrease platelet aggregation 'O-''

Changes in blood flow 8~14~15

Improvement or facilitation of learning and memory processes l6

Anti-stress activity l6

Modulations of endocrine and immune systems 16-18

Modulation of cellular metabolic processes on carbohydrate, fat and protein metabolism l6

' Yonezawa et ai., 1976 Takeda et al., 1981 Yonezawa et al., 1981; 1985 Takeda et al., 1982 Zhang et al., 1987

6 Wood et al., 1964 Lee et al., 1981 Chen et al, 1984 Lei and Chiou, 1986

'O Matsuda et al., 1986a; 1986b l ' Kimura et al., 1988 l2 Matsuda et al., 1989 l 3 Teng et al., 1989 l4 Kaku et ai., 1975 l5 Hata et al., 1985 l6 Liu and Xiao, 1992 l7 Komo et al., 1984 l 8 Konno et al., 1985

Location Yield (tons)

Jilin

Liaoning

Heilongi iang

Total

Table 1.5 Varieties of Panax Species 2L

Botanical Name Common Name

1 Panax quinquefolius L. North American ginseng

2 Panax ginseng C.A. Meyer Chinese or Korean ginseng

3 Panax japonicus C .A. Meyer Japanese ginseng

4 Panax nologinseng F.H. Chen White ginseng

5 Puna pseudoginseng W dl. NIA

6 Panax zingiberensis C .Y. Wu et K.M. Feng NIA

7 Panax stipuleanatus H.T. Tsai et K.M. Feng NIA

NIA - not available

' Yu, 1987 Barna, 1985 Liu and Xiao, 1992

diflerent plants. As a result, the confusion of botanical names is an indication of the

general usage of the word, ginseng.

Although there are many varieties of ginseng, only three species are currently

considered to be medicinally active. They include P. quinquefolius (North American

ginseng), P. ginseng (Chinese or Korean ginseng), and P. japonicus (Japanese ginseng)

[Williams, 1957; Court, 1975; Phillipson and Anderson, 19841. The former two varieties

have similar compositions of nutrient and certain active components (Tables 1.1; 1.2).

However, P. japonicus only shares two common active constituents with P. quinquefolius

and P. ginseng (Section 1.2.3.1) [Bahrke and Morgan, 19943. Despite this difference, P.

japonicus has been used as inexpensive substitutes for the dried root of P. ginseng

[Bahrke and Mogan, 19941. At present, both P. quinquefolius and P. ginseng are sold

worldwide in forms of processed roots, powders, teas and capsules [Liberti and

DerMarderosian, 19781.

1.2.3 Active Components in Ginseng

1.2.3.1 gins en^ saponins: pinsenosides

Many ginseng experts consider ginseng saponins to be the primary biologically

active components of Panax species [Hou, 1977; Phillipson and Anderson, 1984; Liu and

Xiao, 1992; Bahrke and Morgan, 19941. They are known as ginsenosides (GS), of which

28 (Table 1.6) have so far been identified fiom the root, root-stock, stems, leaves, flowers

and flower-buds of the P. ginseng plant (Table 1.7) [Zhang et al., 1979; 1980; Cai et al.,

1982; Kuang and Xu., 1982; Shao and Xu, 1982; Wang et al., 1983; Wang et al., 1986;

Protopanaxadiol Protopanaxatriol Oleanolic Acid

Table 1.7 Ginsenoside Contents in Different Parts of Ginseng Plant ' Part Protopanaxadiol Protopanaxatriol Oleanolic Total Amount

Type (9 Type (%) TY pe (%) (%)

Root 1.1 1 2.19 0.89 4.19

Leaves 1.62 3 .O0 3 .O2 7.64

' Zhang et al., 1979; 1980 Cai et al,, 1982 Kuang and Xu, 1982 Shao and Xu, 1982 Wang et al., 1985 XU et al., 1986a

' XU et al., 1986b, 1986c

dammarane series. They are named Rx, where x is either a letter, or a number, or both,

according to their position on thin layer chromatogram [Phillipson and Anderson, 19841.

According to their chemical structure characteristics, they can be fiirther divided into three

types: oleanolic acid (OA), protopanaxadiol (Diol) and protopanaxatriol (Triol) (Figure

1.1) [Sprecher, 1987; Liu and Xiao, 19921.

Both P. ginseng and P. quinquefohs contain ginsenosides bl, &, Rb3, ]Rc, and

& as Diols; &, Rg1, and Rg2 as Triols; and R,, as OA (Table 1.1) [Sprecher, 19871.

However, they have different composition of GS. For instance, ginsenosides & and Rf

while present in P. ginseng are absent in P. quinquefoIius [Hou, 1977; Sprecher, 19871.

In addition, the approximate ratio of Di01 to Triol of North American ginseng root is

about 6.5 to 1 . On the other hand, this ratio is close to 1 in Oriental ginseng [Hou, 19771.

Accordingly, P. quznquefolius contains substantially more Di01 than P. ginseng. This can

be used to explain why the Chinese believe that American root has different physiological

effects fiom its Chinese cousin [Hou, 19771.

P. japonicus is one of the most famous P. ginseng substitutes ever used in Japan.

Its GS profile is very much different fiom both P. ginseng and P. quinquefolius. It was

reported that the Japanese root contains mainly different saponins. Only ginsenosides Rg2

and & are common to Japanese, Chinese or Korean and American ginsengs [Bahrke and

Morgan, 19941.

There are several factors that affect the amount of GS in the Panax plant. GS exist

not only in the root but also in other parts such as stems, root stock, leaves, flowers and

flower-buds. In fact, it was illustrated that the quantities of GS varied in

20s protopanaxadiol ginsenosides

H

\ 20s protopanaxatriol ginsenosides

Figure 1.1 Chemical structures of différent ginsenosides

Table 1.8 Cornparison of Ginsenoside Contents of 2-9 Old Ginseng ' -- -

Years Total Rb R, R0 Ginsenosides (%) (%) (%) (%)

Zhang et al., 1980

fi . U --r ----- --- J --- va - - - - - -

growth, lowest at two years and reduce after the sixth year [Zhang et al., 19801. This

suggests that the collection period is crucial to its GS quantity which is indicative of the

quality of ginseng.

1.2.3.2 Other active pinsenp: components: ~olysaccharides, ~olypeptides,

flavonoids

Aside from GS, there are other physiologically active principles in ginseng. They

include polysaccharides, polypeptides, a carboxylic acid, adenosine and flavonoids [Konno

et al., 1984; Tomoda et al., 1984; Konno et al., 1985; Oshima et al., 1985; Zhu et al.,

1989; Yang et al., 1990; Yang and Wang, 19911. Ginseng glycans, a type of

polysaccharides, are referred to as panaxans [Konno et al., 1984; Tomoda et al., 1984;

Konno et al., 1985; Oshima et al., 19851, The flavonoid constituents are identified as

kaempferol, tnfolin and panaxasenoide on the basis of chernical and spectroscopic analyses

[Wang et al., 2 9861. However, these compounds are only isolated from P. ginseng and

have not been confirmed in other ginsengs.

1.2.4 An overview of ~harmacoloeical effects of ~inseng

1.2.4.1 Ginsen? as an ada~togen

Very few pharmacological and clinical studies have been conducted with North

American ginseng, despite its similarity to Oriental ginseng (Tables 1.1 ; 1.2). In fact, the

majority of scientific investigations on ginseng were done primarily with P. ginseng in the

past 20 years. Since the nutrient contents and certain active components are common in

Y d - - - - - . . - - - - - , ------ -".Y'-' r--J Y-V.Vb.YU.

properties,

In 1970's ginseng was pharmacologically classified as an adaptogen, by Russian

pharmacologists Brekhman and Dardyrnov [1969a]. They defined it as 'a non-specific,

innocuous substance which improves the resistance of the organism to the most varied

fonns of stress and by its regulating actions restores, revitalizes or enhances homeostasis'.

They also concluded that the basic effect of ginseng action was its potential capacity to

increase non-specific resistance to various stressors [Brekhrnan and Dardyrnov, 1969bI.

Since then, P. ginseng had been associated with a variety of other physiological effects

mostly in animals by other investigators (Table 1.3).

1.2.4.2 Ginsenosides Rb* and R,I

The majority of the pharmacological effects of ginseng listed in Table 1-3 have

been attributed to GS. Among al1 the GS that have been identified, ginsenosides hl and

RgI, which are Di01 and Triol respectively, have attracted much of the attention. Although

both P. quinquefolius and P, gznseng contain RI,^ and Rgl, hi and Rgl are the most

abundant respectively in P. quinquefolius and P. ginseng (Table 1.1) [Sprecher, 1987;

Chuang et al., 19951. Early research suggested that Rb1 suppressed central nervous system

(CNS) activity and had tranquilizing properties, while Rgl possessed slight CNS

stimulation, and vasodilator activities [Takagi et al., 1974; Owen, 198 1 ; Bahrke and

Morgan, 19941. As hl and Rgl CO-exist in both North American and Oriental roots, these

findings seem to support the hypothesis that ginseng acts as an adaptogen which provides

homeostasis [Brekham and Dardyrnov, 1969a; 1969bI.

1.2.4.3 gins en^ ~olvsaccharides and pe~tides

Ginseng polysaccharides and peptides were also shown to be physiologically

active. The polysaccharides were found to markedly stimulate phagocytosis of the

reticuloendothelial system and the production of antibodies [Wang et al., 19801 and had

hypoglycemic activity [Konno et al., 1984; Tomoda et al., 1984; Konno et al., 1985;

Oshima et al., 1985; Yang et al., 1990; Yang and Wang, 199 11. It was reported that these

polysaccharides increased serum complement content in guinea pig, raised serum

immunoglobulin G level in mice, and elevated B-lyrnphatic to T-lymphatic ce11 ratio [Wang

et al., 19801. Consequently, ginseng polysaccharides seem to affect immune fbnctions.

Furthemore, ginseng glycans and peptides extracted fiorn P. ginseng were demonstrated

to have hypoglycemic activity in normal and drug-induced diabetic mice [Konno et al.,

1984; Tomoda et al., 1984; Konno et al., 1985; Oshima et al., 1985; Yang et al., 1990;

Yang and Wang, 19911.

1.2.4.4 A biolo~icallv active ins sen^ ~eptide, a carboxvlic acid and an

adenosine

A peptide with a molecular weight of 1400 [Ando et al., 1979; 19801, a carboxylic

acid [Sekiya et al., 19811 and adenosine [Okuda and Yoshida, 1980; Sekiya et al., 19801

isolated fiom the water extract of P. ginseng were reported to be insulin-like and have

anti-lipolytic properties. The carboxylic acid inhibited lipolysis induced by epinephrine and

thyrotropin [Sekiya et al., 19811. Ginseng flavonoids were reported to influence cardiac

performance and hernodynarnics [Pan and Zhang., 19861.

1.2.4.5 Human Trials

Only a few controlled experiments in humans have been reported. Hallstrom et al.

tested the effects of 1.2 g Korean ginseng or P. gznseng on 12 night-shifl nurses, using

placebo and a good night's sleep as controls in a double-blind, crossover trial [Hallstrom

et al., 19821. Mood and body feelings were assessed before and after each treatment

phase. The results indicated that there was no significant differences between placebo-

and ginseng-treated phase in any of the parameters measured. However, a trend was

noted, especially for mood ratings in ginseng-treated phase. As a result, the authors

concluded that the duration of the study (2 weeks) and the low dosage of ginseng used

might have influenced the outcome. Although blood sugar showed a decline in the

experimental group, this reduction was not significant and the observed levels were in the

normal range before and during the treatment.

McNaughton et al. tested Chinese and Sibenan ginsengs on 30 athletes (15 males

and 15 females) who were randornly assigned to either placebo, or Siberian ginseng, or

Chinese ginseng group [McNaughton et al., 19891. They were instructed to ingest 1 g of

the substance at 8:00 a.m. each rnorning for six weeks. Results showed that Chinese

ginseng- or P. ginseng-treated group had a significantly improved maximal oxygen uptake

when compared to placebo control, while the Siberian ginseng treated group did not differ

recover as indicated by a lower post exercise heart rate, whereas Siberian ginseng had no

difference. These results suggested that Oriental ginseng seemed to be beneficial to

humans, a conclusion that remains controversial.

Engels et al. (1 996) conducted a randomized, double-blind, placebo-controlled

study in which 19 healthy adult females were administered 200 mgld of a concentrated

extract of P. ginseng (n = 10) or placebo (n = 9) to their othenvise supplement-fiee

normal diet. Before and afler the trial intervention, subjects performed a graded maximal

cycle ergometry test to exhaustion and completed a standard habitua1 physical activity

questionnaire. Blood was analysed for lactic acid. It was found in this study that

standardized extract of P. ginseng had no influence on any of the variables measured and

as a result, the authors concluded that Oriental ginseng did not enhance work

performance, change energy metabolism, improve recovery response fiom maximal

physical work.

Recently findings by Cui et al. and Hasegawa et al. demonstrated that ginseng

saponins or GS are detectable in blood [Cui et al., 19961, urine, and feces [Hasegawa et

al., 19961 in human athletes who consumed ginseng preparations orally. These findings

indicate the uptake of ginseng saponins in humans afier oral administration of ginseng

preparations.

1.2.4.5.1 Adverse effects of pinseng

The stimulant effects of ginseng and the potential problems associated with the

long term effects of the use of ginseng, primarily CNS excitation and arousal, were given

the name, Ginseng Abuse Syndrome (GAS) by Siegel [1979]. GAS was defined as

hypertension together with nervousness, sleeplessness, skin eruptions, edema and morning

diarrhea. The range of daily dosage for individuals experiencing this syndrome was found

to be O to 15 g. Siegel claimed that GAS was sirnilar to organic brain syndromes

associated with corticosteroids and corticotropin and might be related to ginseng's

interference with cortisone and corticotropin levels. However, Siegel's views were based

entirely upon self-reported data obtained in a survey of ginseng users as opposed to a

controlled, experimental trial. In addition, Siegel clearly stated that the subjects

consumed a wide variety of commercial ginseng preparations. Therefore, GAS cannot be

assigned solely to ginseng in general.

1.2.5 Hvpoglvcemic effects of pinseng

1.2.5.1 Animal studies

1.2.5.1.1 Ginsenosides

Ginseng has been suggested to have a synergistic action with insulin and also its

own hypoglycemic activity. Yokozawa et al. [1985] showed that a semi-purified saponin

fraction fiom P. ginseng could stimulate various metabolic reactions involved in lipid and

sugar metabolism in normal rats. Other reports indicated that most of the biochemical

actions of the semi-purified saponin extract might due to ginsenoside Rb2 [Yokozawa et

al., 19841. Administration of Rb2 to streptozotocin-induced diabetic rats improved

I I Y I L - - ----- -- ------ ----

had a significant rise of glucokinase activity in the liver and a significant decrease in

glucose-6-phosphatase. This also associated with an increase in hepatic glycogen. As a

result, it was concluded that might elicit its hypoglycemic activity by changing the

levels of gluconeogenic and glycolytic enzymes and shifting the direction of the overall

metabolic flow toward glucose oxidation. The results suggested that the administration of

& to diabetic rats stimulated the lipolytic activity of lipoprotein lipase, with a

corresponding decrease in serurn triglycerides (TG) and very low density lipoprotein

(VLDL). This indicated that RI,^ might play a role in facilitating the re-esterification of TG

fatty acid and glucose in the adipose tissue [Yokozawa et al., 19851. Consequently, the

work provided some evidence that ginsenoside %2 might be a usefùl hypoglycemic agent

and that its action was very similar to the rnetabolic alterations produced by insulin.

1.2.5.1.2 Water (DPGseries) and methanolic (EPGseries) extracts of P.

ginseng

Kimura et al. [1981a; 19821 and Waki et al. El9821 demonstrated that the water

(DPG-series) and methanolic (EPG-series) extracts fiom P. ginseng had hypoglycemic

activity in alloxan diabetic mice injected i.p. with the ginseng fraction. These extracts were

first fiactionated with a water-diethyl ether mixture, then the water layer was further

treated with n-butanol, and the butanol layer was dialyzed. The outer dialyzates yielded

the hypoglycemic extracts called DPG-3-2 and EPG-3-2. EPG-3-2 was reported to

increase blood insulin secretion in normal and diabetic mice [Waki et al., 19821. The

hypoglycemic activity of EPG-3-2 in diabetic mice was abolished by an insulin antiserum,

was found to modiQ the metabolic clearance of insulin. Simultaneous perfusion of the

pancreas with DPG-3-2 and glucose was also s h o w to produce an additive effect on

insulin release in both normal and diabetic rats [Kimura et al., 1981bj. These findings

seemed to suggest that some ginseng fractions could stimulate insulin release, especially

glucose-induced insulin release fiom pancreatic islets, and thereby lowered blood glucose

level [Waki et al., 19821. Furthermore, although both EPG-series and DPG-series extracts

had yet to be fùlly chernically characterized, chemical analyses on these extracts indicated

that these ginseng fractions consisted of unknown substances as major components and

ginseng saponins as minor components, with EPG-series containing more saponins

wmura et al., 1981 a]. However, neither one of them was more effective in lowering

blood glucose than the other, suggesting that the hypoglycemic effect of ginseng fiaction

might not be due to the saponins present as minor components [Kimura et al., 1981al.

Therefore, the hypoglycernic component might be a new principle different fiom GS.

Kimura et al. [l98 1 a] a h andyzed the glucose tolerance curves of hyperglycemic

KK-CAY mice. A comparison was been made between mice receiving a blended Chinese

traditional medicine without ginseng and mice receiving the same medicine with added

ginseng extract, DPG-3-2. It was observed that the mixture with DPG-3-2 decreased the

rise in glucose tolerance curve, indicating that blood glucose was cleared out of circulation

at a faster rate. However, the chernical structure of the active principle in DPG-3-2 had

not been filly elucidated.

--------- --------- --.- r YI----..- -UV". hl 7 YU.." WU...," ,a'... U,.U.IJ

Aside £Yom GS, ginseng polysaccharides were found to exhibit hypoglycemic

activity. Konno et al. [1984] were the first to isolate these polysaccharides or glycans

fiom an aqueous methanoywater extract of P. ginseng. There were currently ten

hypoglycemic glycans recognized which were given the names panaxan A, 13, C, D, E, Q,

R, S, T, and U [Konno et al., 1984; Konno et al., 1985; Oshima et al., 19851. Out of

these 10 panaxans, only panaxan A was chernically characterized [Tomoda et al., 19841.

'H-NMR spectroscopy confirmed that panaxan A was composed mainly of a- l+6 linked

D-glucopyranose residues having branching at the C3 position. However,

spectrum suggested that these cc-glucose units were also linked at the 1, 3, and 6 position

[Tomoda et al., 1 9841.

Al1 of the panaxans were demonstrated to have hypoglycemic response when

injected i.p. into normal mice [Konno et al., 1984; Konno et al., 1984; Oshima et al.,

19851. In addition, Panaxans A, B, and U, when administered i.p. in alloxan-induced

hyperglycemic rnice, lowered plasma glucose level.

The hypoglycemic capability of ginseng polysaccharides was confirmed by Yang,

1990; Yang and Wang, 19911. This group showed that the administration of ginseng

polysaccharides i.p. and S.C. in mice reduced blood glucose and liver glycogen. They also

found an association of ginseng polysaccharides with increases in adenosine-3',5'-cyclic

monophosphate (CAMP) and adenyl cyclase (AC). This action, however, was completely

antagonized by propranolol, an adrenergic P-receptor inhibit or. In addition, both pyruvate

and the activities of succinate dehydrogenase and cytochrome oxidase were found to

suggested that the action of the polysaccharides extracted fiom P. ginseng was related to

adrenergic receptors causing the production of CAMP which in turn activated the break

down of glycogen for aerobic energy production. In fact, the authors believed that the

polysaccharides might stimulate the release of insulin which led to a reduction in blood

glucose and improvement of diabetes control.

1.2.5.1.4 Ginsenp a o l v ~ e ~ t i d e

Wang et al. [1990a; 1990bl reported that ginseng polypeptide extracted from P.

ginseng possessed similar effects as ginseng polysaccharides. When ginseng polypeptide

was administered Z.V. to rats, blood sugar levels and liver glycogen decreased. When mice

were injected SC. daily for seven consecutive days, ginseng polypeptide also reduced

blood glucose and liver glycogen. However, just like ginseng polysaccharides, this effect

was inhibited by pretreatments of pentolamine and propranolol, suggesting that the effect

of ginseng polypeptide on glucose metabolism rnight be related to adrenergic receptors.

In addition, raised plasma glucose concentrations induced by adrenaline, glucose, or

alloxan were ameliorated by ginseng polypeptide. At doses of ginseng polypeptide which

caused decreases in blood glucose and liver glycogen, ginseng polypeptide also inhibited

lactate dehydrogenase activity and stimulated the activities of the tricarboxylic acid cycle

enzymes, succinate dehydrogenase and cytochrome oxidase. As a result, ginseng

polysaccharides and polypeptides are very similar in their effects on hyperglycemia.

There have been very few well-controlled clinical studies on ginseng. However,

Sotaniemi et al. [1995] recently demonstrated in a double-blind placebo-controlled study

consisting of 36 non-insulin dependent diabetes mellitus patients that P. ginseng extract

elevated mood, improved psychophysical performance, reduced fasting blood glucose

(FBG), decreased body weight, and improved glycosylated hemoglobin (HbAic), serum

aminoterminalpropeptide (PIIINP), and physical activity. In addition, they reported that

serum immunoreactive insulin (RI) and lipids were not affected by ginseng therapy.

The authors suggested that the mechanisrn for improved FBG associated with

ginseng may be multifact orial. They indicated that positive changes in psychophysical

performance improved motivation for self-management, leading to changes in diet and

physical activity. FBG reduction without changes in IR1 suggested improved insulin

sensitivity, while decreases in P I I N by ginseng indicated reduced collagen synthesis

and/or improved elimination, which might prove to be anti-antherogenic. Consequently,

the authors concluded that ginseng which activated mood and psychophysical performance

might improve glucose balance.

1.2.6 Mechanism

1.2.6.1 Anti-stress activities of Ginseng

A majority of early scientific research on ginseng were conducted on its stress

resistant capability in the attempt to explain its adaptogenic properties. The homeostatic

effect of ginseng is different from that of stimulants in that while stimulants affect

, y - - U - - - - - - - - - - - - - - ---- ------- J ------- ---- -- C)-"'""' -Y

faced with a challenge or stress [Fulder, 19811. Pharmacological studies, primarily with

rodents, showed that ginseng or its active components prolonged survival to different

types of stress prekhrnan and Dardymov, 1969a; 1969bl. Physical stress, such as

exposing animals to very hot or cold environments, lethal X-rays, excessive physical work;

chernical stress, such as subjecting animals to medications, poisons, narcotics, toxic anti-

cancer drugs; and biological stress, such as bacterid infections, malaria, surgery,

implantation of cancer, and artificially induced diabetes have al1 been used for more than

twenty years to study the capability and the mechanism of ginseng in eliciting its

adaptogenic properties, and to evaluate its efficacy as claimed by TCM [Fulder, 19931.

1t has generally been agreed that the ability of ginseng to restore homeostasis when

the organism is subject to stress is closely related to the control of the stress hormones. It

is known that corticosteroids and adrenocorticotropic hormone (ACTH) bind directly to

brain tissue in order to increase mental activity during stress and challenge. Fulder El9811

showed that in rats which had been both adrenaIectomized and ovarectomized,

administration of ginseng saponin mixture i.p. for seven days caused a substantial increase

in binding of corticosteroid in lower brain regions two hours after the injection of tritiated

corticosterone. The purpose of removing the adrenal glands and avaries fiom the rats was

to retard the interna1 production of corticosterone. However, when radio-labeled

dexamethasone, a glucocortical analogue, was used instead of corticosteroid, no

differences were observed between ginseng-treated and control rats. This suggested that

ginseng bound specifically on corticosterone. Although the increase in binding of

- - - - - - -- -- . ------- - - --- --- - --- ---- -----

injection due to reduced corticosteroid degradation in the liver, an analysis of cytochrome

P450 activity in the liver did not supported this possibility. In addition, an experiment on

the content of receptor molecules in neurons of the hippocampus showed that there were

similar quantities of receptor in ginseng- and saline-treated rats. As a consequence, Fulder

suggested that there might be an interference with the feedback control of steroid levels in

the body which was established by the hypothalamus, through the pituitary.

Indeed, other investigators also found that GS acted on the pituitary-

adrenocortical system. Using radioimrnunoassay and cornpetitive protein binding method,

Hiai et al. [1979] demonstrated the injection of ginseng saponin mixture i.p. increases

plasma ACTH and corticosterone at 30, 60, and 90 minutes afier the treatment. Isolated

GS, Di01 or Triol, also elevated plasma corticosterone. However, the ginseng-induced

increase in plasma corticosterone was suppressed by pretreatment with dexamethasone.

Hïai et al. Cl9791 concluded that ginseng saponin acted on the hypothalamus andor

hypophysis primanly, and stimulated ACTH secretion which resulted in increased

synthesis of corticosterone in the adrenal cortex.

Fulder [1981] proposed that the adaptogenic or harmonizing nature of ginseng

involved stress steroids. M e r the ingestion of ginseng, the hypothalamus became more

sensitive to stress hormones. When stress occurs, the sensitized hypothalamus acted on

the pituitary to produce large amounts of ACTH which, in turn, acted on the adrenal

glands to manufacture more stress steroids. If stress is prolonged, the sensitized

hypothalamus would detect the level of stress steroids in the body and shut down the

, - - - - -. - - -, . - - - - - - - - - -, ----- - - r r v v u ~ rv vvriuui v v

stress hormones during stress and shut down more quickly when stress stopped. Fulder

[ 198 11 further indicated that the active principles for the regulation of intemal harmony

were GS which were quite sirnilar to steroids in chernical structure (Figure 1.1).

1.2.6.2 Diabetes Mellitus

Non-insulin diabetes mellitus (NIDDM) affects between 5 and 20% of the

population in Western industrialized societies [Harris, 19891 and is associated with a

significant amount of morbidity and mortality [Assmann and Schulte, 19881. However,

there still exist many uncertainties with regards to the pathogenesis of the disease despite

decades of investigative efforts. It has recently been suggested that NIDDM may be more

related to the abnormalities in fat than carbohydrate metabolism [McGarry, 19921.

Approximately 85% of NIDDM patients in the United States are obese [Lillioja et

al., 1988; Eriksson et al., 19891 and that obesity is associated with increased lipolysis,

reflected by increased systernic glycerol and FFA concentrations [Gorden, 1960; Reaven

et al., 19601. In addition, obesity is also associated with insulin resistance, which has been

suggested to be the earliest detectable metabolic defect in patients with NIDDM [Lillioja

et al., 1988; Eriksson et al., 19891. It was shown in both animals and humans that weight

gain decreased insulin sensitivity and glucose tolerance, while weight loss increased them

[Goto et al., 1954; Schliack, 1954; Sims et al., 1973; Pascoe and Storlien, 19901 . It

remains unclear, however, how obesity causes insulin insensitivity. Nevertheless, it was

shown that elevated plasma FFA inhibited insulin-stimulated glucose uptake in healthy

---- J - - - - ---- - - -- - ---- L- - - --- - - -- . y - - - ' J ' ---------- , -- -- -.---*-. -**Wb

physiological elevations of plasma FFA levels lower peripheral insulin sensitivity.

In insulin-dependent diabetes mellitus (IDDM), excess lipolysis is often associated

with hypoinsulinernia. However, adequate insulin therapy usually nomalizes plasma FFA

and triglycerides (TG) levels [Amer et al., 19801. As a consequence, NIDDM differs in

that it is linked to excess lipolysis and hepatic reesterification of FFA to TG which

contributes to high density lipoprotein (HDL) lowering [Kissebah, 1976; Kissebah et al.,

1982; Yki-JaMnen et al., 19891. Although therapeutic intervention may improve

glycemic control in NIDDM, lipoproteins abnormalities usually persist and thereby,

increases the risk of atherosclerosis [Hollenbeck et al., 19861.

1.2.6.3 Possible Mechanism of Ginsen? in Lowering Postprandial Glvcemia

Glucocorticoids are hormones that also pIay a role in the regulation of

carbohydrate metabolism in addition to insulin. Although the complex actions of these

steroids secreted fiom the adrenal cortex are not completely understood, their effects on

carbohydrate metabolism are to facilitate glucagon in its gluconeogenetic action during

fasting. They also inhibit glucose uptake into various peripheral tissues [Moffett et al.,

19931.

Glucocorticoid concentrations Vary throughout the day [Dinneen et al., 19931. In

fact, plasma level of cortisol increases substantially during sleep. As a consequence,

plasma cortisol in the morning has been found to be acutely elevated [Dinneen et al.,

19953. High levels of glucocorticoids or counter-regulatory hormones in plasma lead to

affect glucose uptake [Randle et al., 19631.

When an animal or human is exposed to stress, such as homeostatic stress in the

case of fasting, secretion of ACTH is elevated which brings about a corresponding

increase in glucocorticoids [Moffett et al., 19931. Therefore, elevated leveis of

glucocorticoids are also associated with stress to the body. Durhg an overnight fast, the

body has continuously been exposed to homeostatic stress which results in an elevation of

glucocorticoids. The administration of North American ginseng sensitizes the

hypothalamus by its GS content which, in turn, detects the high level of glucocorticoids

and shuts down their production quickly [Fulder, 19931. With the rapid decline of

glucocorticoids, insulin senstivity improves. Consequently, when a meal is ingested, the

body is prepared or stimulated to clear the postprandial rise in blood glucose out of the

circulation more efficiently. This is not only useful in normal humans, it may also be

helpfùl to NIDDM patients in their daily blood glucose and lipid management.

1.2.7 Conclusion to Literature Review

Ginseng has been used for several thousand of years in China as a tonic,

prophylactic agent and 'restorative'. However, its traditional claims on enhancing overall

body health have been established primarily through clinical or anecdotal experience as

opposed to scientific verification of its pharmacological effects. In the past 20 years,

rnuch scientific research has been conducted on animals to evaluate the efficacy of

ginseng, while there have been very few well-controlled studies on humans. In addition,

Y Y . " u, - - - --- ------ -.--*v".

Chemical analyses show that P. ginseng and P. quinquefolizrs have many GS in

common which are considered to be the active ginseng components responsible for many

pharmacological effects, including improvement of hyperglycemia in diabetic rats. The

hypoglycemic effect of ginseng has been repeatedly demonstrated in animals. In humans,

however, there have been few studies until the recent publication by Sotaniemi et al.

(1995) who showed with NIDDM patients that ginseng extract could elevate mood,

improved psychophysical performance, reduced FBG, decreased body weight and

improved HbAlc, serum PIIINP, and physical activity. This is perhaps the first

demonstration of ginseng efficacy in NIDDM management in humans.

As a consequence, recent findings suggest that Oriental ginseng may be beneficial

in controlling NIDDM. It, however, remains unclear whether North American ginseng

possesses similar physiological effects in humans as the Oriental root despite the simiIarity

of their chemical and nutrient profiles (Tables 1.1, 1.2). Furthemore, it is also uncertain

what the optimal dose and tirne of administration are for either ginseng type. Therefore,

there exists a need to investigate whether whole North Arnerican ginseng root or P.

quinquefolius have any effects on postprandial blood glucose in normal humans and to

determine what the most optimal time and dose of administration are before conducting

studies on NIDDM with North American ginseng root.

1.3 Research Hv~othesis and Obiectives

The hypothesis is that North American ginseng or P. quinquefolius Iowers

glucose challenge.

The main objectives are:

1. To determine whether P. quinquefdlnrs causes a lower postprandial blood glucose

response when taken together with a glucose challenge.

2. To determine if Nonh American ginseng lowers postprandial glycernic response when

taken before a glucose challenge.

3. To determine the most optimal time and dose of administration of North American

ginseng in lowering postprandial glycemia.

CHAPTER TWO

EFFECTS OF NORTH AMEIUCAN GINSENG ON

POSTPRANDIAL GLYCEMIA

- TAKEN TOGETHER WITH A GLUCOSE CHALLENGE -

POSTPRANDIAL GLYCEMIA

-TAKEN TOGETHER WITH A GLUCOSE CHALLENGE-

2.1 Introduction

The traditional method of consuming ginseng is to either to ingest the root or boil

the root in four volumes water until the level becomes one volume. It is nonnally taken on

an empty stomach [Personal communication, Li., 19961. The usual daily dose of Oriental

ginseng in Korea is 6.4 g per day [Personal communication, Park, 19961 . It has been

advised that since North Americans have generally large body size, a higher dose may be

required [Personal communication, Park, 19961. Furthemore, in TCM, the daily dose of

non-toxic herbs is usually in the range of 3 to 10 g, given as decoction or in pi11 or powder

forrn [Bensky and Gamble 19831.

2.2 Aim

The main objective of this study was to determine whether North American

ginseng or P. quznquefoIius can lower postprandial blood glucose when taken together

with a glucose challenge. Doses of 3 g, 6 g, and 9 g North American ginseng powder were

selected for this study in light of the Bensky and Garnble publication [1983].

2.3.1 Glucose challenge preparation and composition

The oral glucose drink (250 mL) was made by diluting 100 mL standardized

glucose solution (75 g glucose / 300 mL) (GIucodex, Rougier Inc.) with 150 rnL of water.

It consisted of 25 g available CHO. It was prepared fiesh on each study day.

2.3.2 Powder form of North American ginseng

The nutrient profile of the North American ginseng powder used in this study is

shown on Table 1.2. The powder was made by grinding the root hair taken from four to

five years old P. quniquefolius grown in Ontario or British Columbia, Canada (Atkins

Farm Ltd., Ontario; Chai-Na-Ta Corp., B .C.). The powder was encapsulated in gelatin

capsules, with each capsule containing either 490 mg or 500 mg of North American

ginseng powder. Al1 the ginseng powder capsules used in the study were generously

supplied by the two manufacturers (Atkins Farm Ltd., Ontario; Chai-Na-Ta Corp., B.C.)

and were obtained fiom the same manufacturers' batch.

2.3.3 Subiect recruitment and ~rofi le

Healthy non-smokers, with no previous history of diabetes or related metabolic

diseases, were recruited to participate in the study. None of them were not taking any

medications. Written consent (Appendix 1), approved by the Human Subjects Review

Committee at University of Toronto, was obtained fiom each subject aRer they had been

fully informed about the procedure and involvement required in the study.

28.6 + 3.1 years. The mean BMI was 24.0 f 1.1 kg/m2 and the mean fasting blood

glucose (FBG) was 4.7 f O. 1 mmol/L. Subject characteristics are Iisted in Table 2.1.

2.3.4 Experimental Desim

This study made use of a randomized, cross-over design in which each subject is

hisher own control. The oral glucose drink was prepared on each test day for the

subjects. Subjects were evaluated on six occasions. The control (glucose challenge) was

adiministered three times. The treatments consisted of three different doses of P.

quinquefolius powder taken together with the glucose drink as treatment, after a 10 to 12

hour-ovemight fast. Each of the subjects was randomized in an unique sequence of test

order as follows:

C- TX-C-Ty-Tz-C

(C = control, T = North American ginseng tests, x,y,z = different doses)

The control was administered three times in order to standardize intra-individual variation.

In addition, there was a washout period of at least two days between each test. Subjects

were asked to repeat a specific test if the result was significantly different (+ 2 SD) fiom

the group mean.

. - - ---. - - - - --- - - ----- F-- --.--i.-...-uii

Subjects were asked to corne to the Risk Factor Modification Centre at St.

Michael's Hospital afier a 10 to 12 hour-overnight fast. Finger-prick capillary blood

samples (250 yL) were taken at fasting and 15, 30, 45, 60, 90, and 120 minutes after

consumption of control or test. Before, collecting fasting blood, subjects were required to

be seated for 10 minutes and remain seated for the duration of the study. M e r the fasting

sample had been obtained, subjects were instructed to consume the glucose challenge

either with various doses of ginseng powder (3 g, 6 g, or 9 g) (T) or without ginseng for

control (C) steadily in 10 minutes. Finger-prick capillary blood samples were obtained

with Autolet Lancets (Owen Mudord Ltd., Woodstock, Oxon). Blood samples were

contained in pre-labeled fluoro-oxalate tubes and were kept frozen at - 2 0 ' ~ pior to

glucose analysis within 48 hours.

Characteristics Total (n=8) Males (n=5) Females (n=3)

Mean I SE Mean $: SE Mean f SE

(range) (range) (range)

Age (years) 28.6 + 3.1 30.4 15.0 25.7 f 1.7

(22.0 to 49.0) (23.0 to 49.0) (24.0 to 29.0)

BMI (kg/m2) 24.0 f: 1.1 24.9 I 1.4 22.4 f 1.6

(20.3 to 28.4) (20.6 to 28.4) (20.3 to 25.6)

FBG (mmoVL) 4.7 k 0.1 4.7 + O. 1 4.7 f 0.1

(4.4 to 5.0) (4.4 to 5.0) (4.6 to 4.8)

Capillary blood glucose concentrations were rneasured using an automatic analyzer

Stat Glucose Analyser, Yellow Springs Instruments, Yellow Spring, OH). This I

device utilizes the glucose oxidase technique [Shimizu et al., 19801. A standard glucose

solution, prepared by dissolving 1.8 g D-glucose in 1.0 L of distilled water, was used to

calibrate the glucose analyser. Al1 the sarnples were analysed only afier two successive

readings of the standard solution between 9.9 to 10.1 rnrnoi/L had been attained.

The glucose analyser is dependent on glucose oxidase to measure glucose

concentrations in blood. When a-D-glucose in blood samples makes contact with the

immobilized enzyme, glucose oxidase, it is rapidly oxidized producing hydrogen peroxide

@&O2). This H202 is, in turn, oxidized at the platinum anode, producing electrons. A

dynamic equilibrium is achieved when the rate of Hz02 production and the rate at which

hydrogen peroxide leaves the immobilized glucose oxidase layer are equivalent. This

equilibrium is indicated by a steady state response. The electron flow is linearly correlated

to the steady state of H z 0 2 concentration and therefore, also to the concentration of

glucose.

2.3.7 Statistical analvsis

Results were expressed as mean + standard error (SE), Incremental area under the

glucose curve (AUC), omitting area beneath the fasting level, was calculated geometrically

[Wolever et al., 19911. Statistical cornparisons of data at specific time points, glucose

peak, and AUC were done by repeated measures ANOVA. Newman-Keuls method was

- -

considered statistically significant if p < 0.05.

2.4 Results

2.4.1 Effects of North American einsen~ on postprandial ~lycemic

response when taken together with a ~lucose challenpe

There was no statistically significant diference at any of the time points, glucose

peak, nor AUC (Figures 2.1; 2.2; Table 2.2) among the control, and 3 g, 6 g, and 9 g

ginseng treatment. The mean + SE of al1 the time points and AUC are listed on Table 2.2.

-+ Control +- 3 g ginseng + 6 g ginseng -+ 9 g ginseng

I I I 1 I I 1 l 1 I I I i O 10 20 30 40 50 60 70 80 90 100 110 120 130

Time (minutes)

Figure 2.1 Effect of North American ginseng taken together with a glucose challenge on postprandial glycemic response (n = 8). Values are means I SE.

U Control €d3 g ginseng üiiïi 6 g ginseng

T EBd9 g ginseng

Control 3 g ginseng 6 g ginseng 9 g ginseng

Figure 2.2 lncremental area under glycernic response curve: North American ginseng taken toget her wit h a glucose challenge (n = 8). Values are means f SE.

Table 2.2 Blood glucose concentrations at specific tirne points, change in blood glucose peak and incremental areas under t

curve (AUC).

Ginseng BIood glucose concentrations (mmoVL) AUC (mmol.min/

A in O' 15' 30' 45' 60' 90' 120' Glucose Peak

Control 4.6 * 0.1 6.5 k 0.3 7.1 -t 0.3 6.4 f 0.5 5.3 + 0.4 4.4 * 0.2 4.3 f 0.1 2.5 Ic: 0.1 112.9 f 16

3 4.7k0.3 7.1 f 0.3 7.5k0.2 6.1 f 0.2 4.9'0.1 4.5'0.1 4.4'0.1 2.8k0.4 104.4 k 1 1

Values are mean f SE

The results indicated that there were no statistically significant differences in

postprandial blood glucose response between the treatments (3 g, 6 g and 9 g of North

American ginseng taken with a glucose challenge) and the control ( the glucose challenge

without any ginseng treatment).

However, one possible explanation might be that since ginseng did not interact with

the food, there was no change in the physical nature of food, such as changing food

viscosity as seen in the case of some soluble dietary fibres. The administration of ginseng

together with the glucose drink did not therefore, cause any changes in glucose absorption

rate. If ginseng caused any reduction in postprandial glycemia, it might be a result of

some other biological pathway. In other words, it might be certain pharmacological

phenornena rather than the physical alteration of food which entraps nutrients.

CHAPTER THREE

EFFECTS OF NORTH AMERICAN GINSENG ON

POSTPRANDIAL GLYCEMIA

- TAKEN PRIOR TO A GLUCOSE CHALLENGE -

- -- - - - .

POSTPRANDIAL GLYCEMIA

-TAKEN PRIOR TO A GLUCOSE CHALLENGE-

3.1 Introduction

In the previous experiment (Chapter 2), it was shown that when ginseng was

taken together with a glucose drink, it did not reduce postprandial blood glucose.

Therefore, it was hypothesized that ginseng might elicit its blood glucose lowering effects

through systemic pharmacological pathway other than physical nature of nutrients. The

traditional way of consurning ginseng is on empty stomach [Personal communication, Li,

19961. Perhaps, ginseng should be taken before the glucose challenge so that it can

'prime' or 'prepare' the system for physiological challenges.

3.2 Aim

The objective of this experiment was, therefore, to determine if North American

ginseng can reduce postprandial glycemia when it is administered before the glucose

challenge. The same oral glucose dnnk as Experiment 1 (Chapter 2) and 9 g of P.

qziinpefolius were used in this experiment. Finger-prick capillary blood samples were

collected at various time points and glucose concentrations were measured.

3.3 Materials and Methods

3.3.1 The com~ositions of glucose challenye and North American pinseng

Both the glucose drink and the ginseng powder used in this experiment were the

same as the ones used in the previous experiment (Sections 2.3.1; 2.3.2).

3.3.2 Subiect recruitment and ~rof i l e

The subject selection criteria were the same as Experiment 1 (Chapter 2). Written

consent (Appendix 1), approved by the Hurnans Subject Review Cornmittee, University

of Toronto, was submitted by each subject.

Seven subj ects (3 males + 4 females) were recruited. They were al1 normal at the

time of the study. Their mean age, BMI, and FBG were 31 f 4.2 years, 23 f 1.2 kg/m2,

and 4.5 f 0.1 rnrnoVL respectively. Subject characteristics are shown in Table 3.1.

3.3.3 Experirnental de-

This experiment employed a randomized, cross-over design. Thus, each subject

acted as hisher own control. There were a total of three separate tests, consisting of a

glucose challenge, ginseng control, and ginseng treatrnent (Figure 3.1). Subjects were

randomized to various sequences of test order. They were asked to perform each test

after a 10 to 12 hou-ovemight fast. The glucose drink was prepared fiesh on each test

day .

I I I 1 I

-80 O 15 30 45 60 90 min

'r T

Glucose ControI 300 mL water 250 mL glucose drink

Ginseng + Glucose 300 mL water 250 mL glucose drink + 9 g ginseng

Ginseng Control 300 mL water 250 mL water + 9 g ginseng

Figure 3.1 Experimental design

3.3.4 Studv ~rocedure and blood sam~Ie collection

Subjects were requested to attend the Risk Factor Modification Centre at St.

Michae17s Hospital following a 10 to 12 hour-overnight fast. Upon arrival, subjects were

asked to remain seated throughout the duration of the study. Fasting finger-prick capillary

blood sample was taken at the beginning using Autolet Lancets (Owen Mumford Ltd.,

Woodstock, Oxon), followed by an ingestion of 9 g North American ginseng powder

contained in gelatin capsules with 250 to 400 rnL of water. After 80 minutes, another

finger-prick blood sample was obtained. A glucose challenge, consisted of 25 g glucose,

was then consumed. Further finger-prick blood samples were collected at 15, 30, 45, 60,

and 90 minutes f i e r the glucose challenge.

For glucose and ginseng controls, finger-prick blood samples were also collected

at the same specified time points. For the glucose control, 300 rnL of water was given

without any ginseng pnor to the glucose challenge. For the ginseng control, 250 rnL of

water was ingested instead of the glucose drink following the consumption of 9 g ginseng

powder. This protocol provided possible control for postprandial glycemic response

attributed to North Arnencan ginseng powder.

Al1 blood samples were collected in pre-labeled fluoro-oxalate tubes. They were

kept fiozen at -20 OC before glucose analysis within 48 hours.

Table 3.1 Subject Profile

Characteristics Total (n=7) Males (n=3) Females (n=4)

Mean f SE Mean f SE Mean f SE

(range) (range) (range)

Age (years) 31.0 f 4.2 33.7 + 7.9 29.0 + 5.3

(23.0 to 49.0) (23.0 to 49.0) (23.0 to 45.0)

BMI (kg/m2) 24.0 f 1.1 25.1 + 1.7 23.1 + 1.7

(20.1 to 28.4) (23.4 to 28.4) (20.3 to 28.0)

FBG (mmoi/L) 4.5 + O. 1 4.6 1 O. 1 4.5 f O. 1

(4.3 to 4.9) (4.3 to 4.9) (4.2 to 4.8)

3.3-5 Blood plucose analvsis

Capillary blood samples were measured using the same procedure and equipment

as the previous experiment (Section 2.3.6).

3.3.6 Statistical analvsis

Results were expressed as mean + SE. Statistical comparisons of data at specific

time points, glucose peak, and AUC were done by one-way ANOVA with repeated

measures. Newman-Keuls method was used as a post test to compare individual means

for multiple comparisons. Differences were considered to be statistically significantly

different if p < 0.05.

3.4 Results

3.4.1 Effects of North American gins en^ on ~ostprandial blood

glucose resDonse when taken before the glucose challenpe

Ginseng + glucose resulted in a 30.3 + 6.4% decrease (p < 0.01) in AUC from that

of the glucose alone (Figure 3.1). Both the AUC of the glucose alone and ginseng +

glucose were substantially larger (p < 0.001) than that of the ginseng alone (Table 3.2). In

fact, the AUC of ginseng alone was deterrnined at 1.6 + 1.4 mmol.min/L, while the AUC

of the glucose alone and ginseng + glucose were respectively found to be 120.0 + 9.4 and

82.3 + 8.2 mmol.minL (Figure 3.1).

North American ginseng taken at 80 minutes prior to the glucose load produced a

significantly lower (p c0.05) blood glucose concentration on the postprandial glycemic

Table 3.2). Blood glucose concentrations at 15, 30, 45 and 60 minutes on the ginseng

control curve were also significantly lower (p< 0.05) than that on both the glucose control

and ginseng treatment (Table 3.2).

Ginseng alone

E Glucose alone mm Ginseng + Glucose

Figure 3.2 lncremental area under glycemic response curve: North Arnerican gineng taken prior to a glucose challenge (n = 7). Values are means * SE. Means with different letters differ significantly (p < 0.05) by ANOVA.

Table 3.2 Blood glucose concentrations at specific time points, change in blood glucose peak,

and incremental areas under the curve (AUC)

Blood glucose concentrations (mmoVL) AUC (mmol.min/l

A in -80' O' 15' 30' 45' 60' 90' Glucose Peak

a a a a a a Ginsengalone 4.5f0.1 4.520.1 4.4f0.1 4.410.1 4.410.2 4.3f0.1 4.4f0.1 0.2M.1 1.6f 1.4

b b b b b b Glucose alone 4.5 I 0.1 4.5 + 0.1 5.9 I 0.3 7.7 k 0.3 6.9k0.2 5.0 f 0.3 4.2 kO.l 3.3M.2 120.0 I 9.4

Ginseng + b c c b c c Glucose 4.5 IO.l 4.6 IO.l 6.2 I 0.1 7.1 f 0.2 5.8 f0.4 4.8 2 0.3 4.2 f 0.1 2.4H.2 82.3 f 8.1

Values are mean ' SE. Means with different letter superscnpts within a column differ significantly (p<0.05) as determined by ANOV followed by Neuman-Keuls method.

9- Blood Glucose Concentration + Ginseng (mmow -A- Glucose

4-

Time (minutes)

Figure 3.3 Effect of North American ginseng on postprandid blood glucose when taken prior to a glucose challenge (n = 7). Values are means SE. Means with different letters verticalIy differ significantly (p < 0.05) by ANOVA.

3.5 Discussion

The results indicated that 9 g P. quinquefolius powder when administered 80

minutes pior to glucose challenge reduced postprandial blood glucose peak at 30 minutes

and decreased AUC by 31.4%. AUC on the ginseng control curve was found to be

negligible which indicated that ginseng powder alone did not contribute significantly to the

postprandial rise in blood glucose. As a result, AUC on the ginseng treatment curve did

not need to be adjusted.

This finding showed that North Amencan ginseng taken pior to glucose load was

effective in lowering post-meal blood glucose in normal humans, which might indicate that

it was a pharmacological effect. However, it remained uncertain whether there was an

effective time and dose of administering ginseng powder .

CHAPTER FOUR

OPTIMAL TIME AND DOSE OF

NORTH AMERICAN GINSENG ADMINISTRATION

NORTH AMERICAN GINSENG ADMINISTRATION

4.1 Introduction

P. quinquefolius has been demonstrated to lower postprandial blood glucose

response when taken prior to a glucose load (Chapter 3). This finding is the first time in

which North Arnerican ginseng is shown to have a postprandial hypoglycemic response in

healthy humans. This effect, however, is not seen when administered together with the

glucose drink (Chapter 2). Thus, the purpose of this phase is to determine the optimal

time and dose of taking North Arnerican ginseng powder.

4.2 Aim

The main purpose of this study was to find the optimal dose and time of taking

North Amencan ginseng powder such that the maximal postprandial hypoglycemic effect

can be elicited. Doses of 3 g, 6 g, and 9 g of P. quinquefolius were selected as

Experiment 1 for the same reason (Chapter 2). Each of these doses will be taken at 40,

80, and 120 minutes before the glucose challenge.

4.3 Materials and Methods

4.3.1 The com~osition of standard meal and North American ginseng

Both the standard meal and the ginseng powder used in this study was the same as

the ones used in the previous experiments (Sections 2.3.1 ; 2.3.2).

The requirements for selecting subjects for this phase were identical to the ones in

Experiments 1 and 2 (Chapters 2; 3). Al1 subjects were asked to return a signed consent

form (Appendix 1) that had been approved by the Humans Subject Review Cornmittee of

University of Toronto.

There were altogether six subjects (4 males + 2 females) participated in this study.

They were al1 healthy non-srnokers at the time of the study. They had an average age of

36.7 f 5.4 years, a mean BMI of 25.1 & 1.3 kg/m2, and a mean FBG of 4.4 + 0.1 mrnol/L.

Subject characteristics are shown in Table 4.1.

4.3.3 Experimental d e s i ~ n

This study employed a randomized, cross-over design in which each subject is his

or her own control. There were a total of twelve tests, comprising three different doses of

North American ginseng (3 g, 6 g, and 9 g), each of which was taken at three different

times (-120, -80, and -40) prior to meal, and three glucose controls. There was a washout

period of at least two days. Al1 subjects were randomized to an unique sequence of test

order as follows:

where C = control, T = North Arnerican ginseng test,

and 1 ,. .,9 = different dose and time

They were also asked to perform each test afier a 10 to 12 hour overnight fast. The oral

glucose drink was prepared on each test day.

4.3.4 Studv ~rocedure and blood sarnple collection

Subjects were asked to corne to the Risk Factor Modification Centre, St.

Michael's Hospital following a 10 to 12 hour overnight fast. Throughout the duration of

the study, al1 participants were asked to remain seated. A fasting blood sarnple was

collected before any ingestion using Autolet Lancets (Owen Mumford Ltd., Woodstock,

Oxon). For the control (C), subjects were asked to consume a glucose drink, which

consisted of 25 g glucose, and collect blood at 15, 30, 45, 60, and 90 minutes. For

ginseng powder tests (T), either 3 g, 6 g, or 9 g North American ginseng powder was

taken with 300 mL water. After either 40, 80, or 120 minutes, another finger-prick blood

sample was obtained. A glucose drink, containing 25 g glucose, was then consumed.

Further capillary blood samples were collected at 15, 30, 45, 60, and 90 minutes after

ingestion of the glucose challenge. Al1 blood samples were contained in pre-labeled

fluoro-oxalate tubes. They were kept fiozen at -20 OC before glucose analysis within 48

hours.

4.3.5 Blood plucose analvsis

Finger-prick capillary blood samples were measured using the same procedure and

equipment described in Chapter 2 (Section 2.2.6).

4.3.6 Statistical Analvsis

Results were presented as mean + SE. Statistical comparisons of AUC for al1

three doses and time of ginseng administration were done by two-way ANOVA (Table

4.2). One-way ANOVA with repeated measures was employed to further compare the

effectiveness of each given dose ingested at each specified time with that of the control.

Comparisons of data at specific time points for each dose with glucose control were done

by one-way ANOVA. Newman-Keuls post test was used to compare individual means for

multiple comparisons following both two-way ANOVA and one-way ANOVA.

Differences were statistically significant if p < 0.05.

4.4 Results

When 3 g and 6 g of North Arnerican ginseng powder were taken at either 40 (p <

0.05) or 80 minutes (p < 0.05) pnor to the glucose drink, it resulted in a lower AUC as

compared to glucose alone. Lower AUC's were also seen when 9 g of P. quinquefolius

powder was ingested at either 40 (p < 0.01), 80 minutes (p < 0.01), or 120 minutes (p <

0.05) before the glucose challenge. (Figure 4.1). However, AUC's for al1 three doses of

ginseng powder taken at 40, 80, and 120 minutes before glucose challenge were not

significantly different (Table 4.2). In addition, niether time, dose nor the interaction

between time and dose appeared to contribute to the overall reduction of postprandial

glycemia.

ginseng powder at either 40, 80, or 120 minutes before the glucose load are show in

Figure 4.2. Although there was no significant difference, it appeared that 3 g, 6 g, and 9 g

of ginseng powder ingested 40 minutes prior to glucose load tended to have greater

reductions in postprandial hypoglycernic response (Figure 4.2).

Lower blood glucose concentrations at 45 minutes were found when 3 g, 6 g, 9 g

ginseng were taken at 40 and 80 minutes before glucose challenge when compared to

glucose alone (Figures 4.3; 4.4; 4.5).

Table 4.1 Subject Profile.

Characteris tics Total (n=6) Males (n=4) Females (n=2)

Mean f SE Mean + SE Profile

(range) (range)

Age (years) 36.7 f 5.4 36.8 f 7.1 25.0 and 48.0

(23.0 to 49.0) (23.0 to 49.0)

BMI (kg/m2) 25.1 f 1.3 25.3 f 1.1 20.2 and 28.9

(20.2 to 28.9) (23.6 to 28.4)

FBG (mmoVL) 4.4 f 0.1 4.4 +_ 0.1 4.2 and 4.8

(4.4 to 4.9) (4.4 to 4.9)

Glucose alone

ml -40 minutes H -80 minutes

ab O -120 minutes b

b r a b b

T

Figure 4.1 Incremental area under glycemic response curve: 3 g, 6 g, 9 g of North American ginseng powder taken at -40, -80, -120 minutes before a glucose challenge (n=6). Values are means f SE. Means with different letters differ significantly (p < 0.05) by ANOVA.

American ginseng powder administration tirne, dose, and tirne-dose interaction.

Source p-value

Dose 1073.2 2 536.6 0.58 0.5613

Dose-Time Interaction 182.9 4 45.7 0.05 0.9952

Time of North American ginseng powder administration (minutes)

Figure 4.2 Percent reduction in AUC wi th different ti me and dose of North Arnerican ginseng powder administration (n=6). Values are means f SE.

+ Glucose alone + -40 minutes + -80 minutes + - 120 minutes

,O 4- rn

3 1 I 1 I 1 1 I 1 1 I

O 10 I

20 30 40 50 60 70 80 90 1 O0

Time (minutes)

Figure 4.3 Effects of 3 g North American ginseng on postprandial blood glucose when taken at 40,80,120 minutes prior to a glucose challenge (n = 6). Values are means SE. Means with different letters vertically differ significantly (p < 0.05).

+ Glucose donc + -40 minutes + -80 mi nutes -e -120 mi nutes

40 50 60

Ti me (mi nutes)

Figure 4.4 Effects of6 g North American ginseng on postprandial blood glucose when taken at 40,80,120 minutes prior to a glucose challenge (n = 6). Values are means * SE. Means with different letters vertically diffcr significantly (p < 0.05).

+ Glucose alone -t -40 mi nutes + -80 minutes + -120 minutes

Time (mi nutes)

Figure 4 5 Effects of 9 g North American ginseng on postprandial blood glucose when taken at 40,80,120 mi nutes prior to a glucose challenge (n = 6). Values are means i SE. Means w ith different letters vertical1 y differ significantl y (p < 0.05).

These results confirmed the previous finding (Chapter 3) that 9 g of North

American ginseng powder administered 80 minutes before a glucose challenge resulted in

a decreased postprandial blood glucose response (p < 0.01) as shown by a lower AUC

compared to glucose alone (Figure 4.1).

North American ginseng powder (3 g, 6 g, 9 g) taken either at 40 or 80 minutes

before glucose challenge lowered postprandial glycemic response by decreasing blood

glucose concentrations at 45 minutes after the glucose load (Figures 4.3; 4.4; 4.5).

Neither time nor the interaction between time and dose appeared to play a role in reducing

postprandial glycemic response (Table 4.2). However, a trend was be seen (Figure 4.1) in

that North Anerican ginseng powder (3 g, 6 g, 9 g) taken closer to the glucose challenge

time appeared to cause a greater decrease in AUC. This level of reduction seemed to

gradually diminish as ginseng was ingested further fiom glucose ingestion time. A greater

sample size would be necessary to confirm this trend.

Since there was no significant difference in percent reduction of AUC among the

three dosages taken at three difference times, an optimal time and dose of administering

North Amencan ginseng powder could not be determined. This might suggest that lower

doses of ginseng need to be further tested. However, it could be concluded that lower

doses of ginseng powder (3 g and 6 g) elicited postprandial hypoglycemic responses in

normal healthy humans when they were taken shortly before the glucose challenge (40 and

80 minutes). A high dose of North American ginseng powder (9 g) produced lower

" - - - - - - - - - - - - - - - - - - - -- .. -- '-'--" -- - Y"V" Y . .W.. a

period of tirne pior to the glucose challenge (40, 80, 120 minutes) (Figure 4.1).

CHAPTER FIVE

GENERAL DISCUSSION

AND

CONCLUSION

5. GENERGL DISCUSSION AND CONCLUSION

5.1 General discussion and future research

Previous studies with animals and humans have suggested that Oriental ginseng

may be useful in treating diabetes [Kimura et al., 1981a; 1981b; Kimura and Suimki,

1982; Waki et al., 1982; Konno et al., 1984; Yokozawa et al., 1984; Konno et al., 1985;

Oshima et al., 1985; Wang et al., 1985; Yokozawa et al., 1985; Sotaniemi et al., 19951.

These findings seem to support the traditional claim that Oriental ginseng is an effective

treatment for diabetes (Section 1.2.1 S). Chemical analyses of Oriental and North

American ginseng have shown that they both contain many reputedly active components

and have very sirnilar nutrient profiles (Tables 1 . l ; 1.2). Consequently, it was

hypothesized in this study that North American ginseng also possesses similar

hypoglycemic effects as its Asian cousin.

Recent findings by Cui et al. [1996] and Hasegawa et al. [1996] demonstrated that

ginseng components could be absorbed. This group was able to detect GS fiagments in

blood, urine, and feces in human athletes who consumed ginseng preparation orally,

suggesting that ginseng saponin fragments were absorbed afier oraI ingestion. In addition,

animal studies in which ginseng components and fractions extracted fiom Oriental ginseng

root were injected i.p. into both chemically-induced and genetic diabetic rats, as well as

normal rats had shown to have hypoglycemic properties [Konno et al., 1984; Konno et al.,

1985; Oshima et al., 19851. Since i.p. injection in animals can be extrapolated to oral

that oral administration of ginseng may have blood glucose lowering effects in humans.

The present study demonstrated that oral ingestion of North American ginseng

with a glucose challenge does not cause any reduction in postprandial blood glucose

response (Chapter Z), while consumption of P. quinquefolius p io r to the glucose

challenge has considerable postprandial hypoglycernic response (Chapters 3; 4). It

appears that since ginseng does not alter the physical nature of food, for example the

viscosity of certain soluble fibres, no change in postprandial blood glucose results when

ginseng is taken together with the glucose load. This suggests that the reduction in blood

glucose response after the glucose dnnk may due to a pharmacological efEect rather than

a physical modification of food causing a decrease in absorption rate in the small intestine.

However, there remain uncertainties about the optimal dose, and whether the time of

ingestion prior to the glucose challenge is a contributing factor to reducing postprandial

glycemia. Nevertheless, this study is the first to demonstrate that North American ginseng

powder when taken orally produces a lower postprandial glycemic response in healthy

individuals. In addition, it also seems to suggest that the eRective dose of North American

ginseng powder rnay be lower than 3 g.

Although decreases in blood glucose and insulin rise after ingestion of

carbohydrate-rich meals sometimes indicate delay of absorption rate [Jenkins et al., 19951,

it remains unclear whether such absorption delay is the result of reduced gastric emptying

or hormonal changes. In addition, plasma insulin which is helpfùl in fiirther understanding

the mechanism by which North American ginseng causes postprandial hypoglycemia was

a , > . . - . - - - ----, -'- - '- "' " " a l ....a au.

human trial for fbture studies on the application of P. qt~inquefoliz~s in the management of

NIDDM, future clinical trials should aim at elucidating the mechanism of ginseng's action

by first determining whether ginseng reduces glucose absorption by slowing ga~tric

emptying or by acting on the endocrine system.

Several factors need to be considered when accounting for a delay in gastric

emptying. Each gelatin capsule in this study contained either 490 mg or 500 mg ginseng

powder. Therefore, the doses of 3 g, 6 g, and 9 g of ginseng used in this study (Section

2.3.2) was consistent of 7, 13, and 19 capsules respectively. As a result, the bulk of the

material may have caused the delay in postprandial glucose absorption by slowing gastric

emptying. However, there was no significant difference between 3 g, 6 g, and 9 g ginseng

powder in lowering postprandial blood glucose despite their differences in material

bulkiness. (Figure 4.1). As a consequence, the material bulkiness of the capsules is

unlikely to be an important factor. In order to firther illustrate this in fbture experiments,

xylose can be given together with ginseng to compare its urinary levels before and after

each test to that of controls with no ginseng. A reduced urinary xylose output tends to

correspond with a dower mouth-to-cecum transit time [knkins et al., 19781, and thereby

indicates delayed gastric emptying. Thus, if there is no change in unnary xylose levels

between ginseng-treated and untreated meals, there is no slowing of gastric emptying

associated with North Arnerican ginseng. Lactulose can also be used to determine

whether gastric transit time is delayed [Jenkins et al., 19781 by comparing breath gases

from lactulose control, glucose alone with lactulose and ginseng treatment with lactulose.

of North American ginseng. Although the exact mechanism is not understood, it is

postulated that it is related to its effects on the hypothalamus during stresshl situations

(Section 1.2.6). As a consequence, it remains unclear how ginseng elicits its

pharrnacological effects. The use of radio-labeled glucose may be usefùl in understanding

the mechanism by which North American ginseng improves overall glucose both normal

and NIDDM individuals. In additiion, fùture studies may also need to measure other

blood parameters in addition to glucose. For example, insulin, free fatty acids, IHDL,

LDL, triglycerides, cortisol, glucagon, and catecholamines measurements can al1 shed light

in understanding the mechanism.

There are many different species of Panmc known to exkt (Table 1.5). Besides,

there are other plants which have sirnilar appearance as Panmc species but are botanically

different. Furthemore, some of the ginseng components Vary in quantities depending on

the year of growth (Table 1.7) which may affect potency of the ginseng. It has been

illustrated that certain GS are of highest quantity at four or five year of growth [Zhang et

al., 19801. As a consequence, it is important for future that the particular variety of

ginseng chosen is, in fact, P. quinquefolius and that they are selected from the same

manufacturer batch of four to five year-old roots. It may also be necessary to assay

certain ginseng components and determine the nutrient profile of any new supplies of

ginseng so that ginseng material can be better standardized. For more consistent ginseng

materials, standardized ginseng extracts rnay also be useful in ensuring potency.

and diabetic humans, a similar protocol can be used to test the effectiveness of other

Panax species with similar year of growth in the lowering of postprandial glycemia. In

addition, the optimal time and dose of administration of each species and their possible

mechanism of action can also be determined. As a result, in the fùture it may be possible

to rank different Panax species of ginseng in order of effectiveness. Long-term human

trials with NIDDM patients can also give light to the possibility of including North

Arnerican ginseng powder in overall NIDDM management.

5.2 General conclusion

The overall objective was to determine if North American ginseng powder could

lower postprandial blood glucose response. North American ginseng taken together with

a glucose challenge did not lower postprandial glycemic response, while ginseng taken at

any given dose with given time prior to the glucose load greatly reduced postprandial

blood glucose response. This indicated that ginseng might elicit its postprandial blood

glucose lowering effect by certain pharmacological pathways, instead of altenng the

physical nature of food substances to entrap nutrients.

The results of this study also suggested that P. quinquefolius (3 g, 6 g, 9 g)

lowered postprandial glycemia when it was taken either at 40 or 80 minutes prior to the

glucose challenge. In addition, at a high dose of 9 g ginseng taken at 120 minutes pior to

the glucose load also produced a similar reduction in postprandial blood glucose. This

suggests that the dose levels selected in this study may be too high to detect the

ginseng administration by developing dose curves fiom O to 3 g and at deterimining the

optimal time of ginseng administration.

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APPENDIX

CONSENT FORM

INTRODUCTION

Ginseng is a man-shaped root indigenous to Asia, North America and Russia. Its value in promoting overall body health has long been recognized by the Chinese as precious and renowned. In fact, they have been using ginseng for more than 5,000 years. Ginseng has traditionafly been thought to prolong fife, boost energy, elevate sex drive and soothe base emotions. Over the years, many other conditions, including diabetes, have been reported to be alleviated by the constant consumption of ginseng. However, these claims are generally based upon anecdotal evidence. Therefore, the purpose of this study is to investigate the efficacy of North American ginseng in normal humans and to determine the time and dose of administration.

PROCEDURES

Phase 1:

This phase consists of 12 individual tests in which each test lasts for a maximum of 3.5 hours. In each test, I will be asked to come to the Clinical Nutrition and Risk Factor Modification Centre, 61 Queen Street East after a 10-12 hour-ovemight fast. 1 will give seven capillary blood samples in each test. Each sample requires 3-5 drops (1/4 tablespoon) of blood.

When 1 reach the Clinic, 1 will give a fasting finger prick capillary blood sample. Then, 1 will ingest either 3, 6, or 9 g (7, 13, 18 capsules) of North American ginseng powder contained in gelatin capsules 1 120, 240, or 360 mg (4, 8, or 12 capsules) of North American ginseng extract contained in soR gel capsules with 250-400 mL water in 10 minutes. After either 40, 80, or 120 minutes, 1 will give yet another finger prick capillary blood sample.

1 will then take an oral orange glucose drink consisting of 100 mL Glucodex@ @M 00509965) and 150 mL water. This drink contains 25 g glucose. Once again, 1 will collect finger prick capillary blood at 15, 30, 45, 60 and 90 minutes afier consuming the glucose drink. The blood samples will be analyzed for glucose levels,

This phase consists of 2 individual tests in which each test lasts for a maximum of 2.5 hours. In each test, 1 will be asked to corne to the Clinical Nutrition and Risk Factor Modification Centre, 61 Queen Street East after a 10-12 hour-overnight fast. 1 will give 8 venous blood samples in each test. Each sample requires 30 mL (2 tablespoons) of blood.

When 1 reach the Clinic, 1 will give a fasting venous blood sample. I will consume either 3, 6, or 9 g (7, 2 3, or 18 capsules) of North American ginseng powder contained in gelatin capsules / 120, 240, or 360 mg (4, 8, or 12 capsules) of North h e r i c a n ginseng extract contained in soft gel capsules with 250-400 mL water in 10 minutes with 250 - 400 mL water.

M e r either 40, 80, or 120 minutes, 1 will give another venous blood sample. 1 will then drink an oral orange glucose drink contain 100 mL GlucodexB @IN 00509965) and 150 mL water. This dnnk has 25 g glucose.

Venous blood sample will be taken at 15, 30, 45, 60, 90, and 120 minutes afier the ingestion of the orange drink. The venous blood samples will be analyzed for hormones and lipids.

RISKS

There are no known risks from ginseng powder and extract. However, minor discornfort is expected when the needle is inserted into my vein. Bniising may occur when the needle is removed but this can be prevent by keeping pressure on the site for 3-5 minutes after the removal of the needle. If bruising occurs, it will go away in 2-3 days.

BENEFITS

1 may expect to benefit from this study in the following ways: my blood sugar, blood lipids, blood hormones may improve. 1 will receive the benefits of evaluation of symptoms and general health discussions with the doctor and help in finding additional treatment if needed. 1 wiI1 have a chance to contribute to a study which may be of benefit to people in the fùture.

CONFIDENTIALITY

The results from the study will be confidential. My results will not be shown to anyone, unless required by law, with my written permission. My results will be sent to my physician if 1 wish.

1 understand that the study investigator may stop my being in the study at any time without my consent. My participation may be discontinued if the study investigator judges that this is in my best interest or if 1 fail to comply to study procedures.

QUALIFICATIONS

1 understand 1 cannot be in this study if 1 abuse alcohol or drugs, of if 1 have a senous illness which is not under control. 1 am above the age of 18 years.

CONSENT

1 have read this consent form, have had al1 my questions about the study answered, and believe 1 know what will happen to me if 1 agree to be a part of the study. 1 understand that 1 may reach Dr. Vladimir Vuksan at (416) 867-7450 if 1 have further questions pertaining to the study.

1 may quit at any tirne. If 1 decide not to participate or quit, 1 will not be penalized and wiI1 not give up any benefits of which 1 had before entering the study. If 1 decide not to participate or quit, 1 will notiQ the study investigator. 1 have received a copy of this consent form.

Volunteer's ................ .................................................. Signature: ........... ................ Date:

Investigator's .................................................. ..................................................... Name: Date:

Investigator's . . . .................................................. Signature : .................................... .. Date:

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