chapter 3

CITRUS RETICULATA BLANCO

REVIEW OF LITERA TURE

CITRUS RETICULATA BLANCO (RUTACEAE)

Introduction

It is a small spiny tree with a dense top of slender branches, believed to have

been introduced sometime in the eighth century A.D. from Indo-China, widely

grown in India.

Syn - C. nobilis Lour.

Vernacular Names

Bengali

Gujarati and Hindi

Kannad

Marathi

Oriya

Tamil

Telungu

Assami

Khasi '

Punjabi

Distribution

Kamla lebu

Narangi, Santra

Kittle

Santra

Kamala, Santra

Kamala, Koorg kudagu orange

Kamalapandu

Kamala, Sumthira

Soh - niamtra

Santara

C. reticulata is a native of China and Cochin China. It is widely cultivated in all

subtropical regions. In India, the areas of concentrated cultivation lie in

Assam, Sikkim, Central India, Punjab and Coorg. The principal tracts of

cultivation in Assam are Khasi and Jaintia hills and the districts of Cachar and

Kamrup, Commercial production in central region is centred in Nagpur,

Bhandara, Wardha, Chindwara and Amraoti districts. In Punjab main areas

are Hoshlarpur and Gurdaspur,

46

■yj* . i

Plate 3.1 : Plants of C itru s reticulata Blanco

Plate 3.2 : Fruit peels of C itru s reticulata

47

Five indigenous cultivars are reported in Assam. These are Soh-niamtra, Soh

Umkait, Nagasantra, Soh-siem and Kapura tenga, extensively grown ail over

Assam, iVleghalaya and Pi/lizoram.

The important orange cultivars cultivated commercially in different parts of

India include 'Nagpur orange, Khasi orange', 'Coorg orange', 'Desi orange,’

'Sikkim orange', 'Butwal' and 'Emperor'. Coorg and Khasi seem to be

ecological forms of the 'Nagpur* (Wealth of India, 1992).

Morphology

It is a spiny, bushy, evergreen shrub or small tree, with a dense top of slender

branches; leaves lanceolate with prominent midrib, petioles narrowly winged

or slightly margined, articulated; flowers white; single or in unbranched

inflorescence, fruits medium to large, flattened or depressed globose, yellow

or reddish orange, core hollow, rind thin, rind and segments easily separable,

segments 10-14, pulp of exceptionally fine quality; seeds, small and beaked

(Kirtikar and Basu, 1991; Wealth of India, 1997).

The fruit peel consists of thin strips with little of the inner white portion of the

rind, 3-4 cm thick. The outer surface Is orange red in colour, glabrous, smooth

glossy, oily and slightly pitted. There are visible oil glands as small dots of dark orange colour.

Chemical Constituents

It is rich in vitamin C and mineral salts. The composition of the fruits is

affected by climate, growing conditions, various treatments and practices,

maturity, rootstock, and variety. The fruits contain citric acid and malic acid

and their salts, reducing sugars, fatty acids, essential oils, glycosides, pectins,

anthocyanins, p-carotene and vitamin C. The composition of C. reticulata fruit

juice is as total yield percentage 38.40-54.70, total solids percentage 7.35-

48

14.56, total acids (as citric acid) percentage 0.37-1.44, total sugars

percentage 6.14-11.65, reducing sugars percentage 2.12-5.33 and vitamin C

mg/100 g 19.71-52.89 (Siddappa et a/,,1954). Thirteen amino acids were

detected from its fmits (Fang et a/.,1985), p-sitosterol, p-amyline and

narlngenin were also isolated from its fruits (Saxena et a/,,1994). Sixteen

compounds were identified and tlie major components included Linallol

(29.68) and citronellal (26.57%) in fallen flower oil (Ding et a i, 1989).

All the parts of plant contains coumarins and psoralins. Crenulatin,

nordentatin, suberenot, suberosln, xanthoxyletin and xanthyletin, are the

reported coumarins and psoralenes (Gray and Watermann, 1978). The fruits

contain flavonoids. They comprise three main groups flavanones, flavones

and 3-hydroxyfiavylium (anthocyanlns); flavanones being predominent

followed by flavones and anthocyanlns. Hesperidine, neohesperidine,

isosakuranetin-7-p-rutinoside, xanthomicrol, noiletin, 5 -O - desmethyl

nobiletin, auranetin, 5-dyhydroxyauranetin, 5,4'-dehydroxy-6,7,8,3'~

tetramethoxy flavone, 3,5,6,7,8,3',4'-heptamethoxyflavone and ponkanetin are

reported (Ranganna et a/., 1983; Wollenweber and Dietz, 1981; Walther et

a/„1966; Chaliha et a/.,1967; Wu, 1987). The fruit peel oil fumishes a number

of constituents, hesperidin, neohesperidin, tangeritin, citromltin and 5-0-

desmethylcitromitin have been reported in Assam Citrus pee\s (Chaliha et

a/.,1965), 6,7-methoxy coumarin, ponkanetin, S-demethylnoblletin, 6,7 -

dimethylescutatin, 4,5,7,8 - tetra methoxyfiavone, limonine, cholesterol,

campesterol, stigmasterol, p- sitosterol from the peel (Lu et a/.,1977; Tatum

and Benry, 1977), limolene in Chenpi (C, reticulata) o\\ was detected by Gas

chromatography, the average recovery was 99.17 % and relative standard

deviation was 0.8% (Ye, 1989), 5- hydroxy -3, 7,8,3', 4*

pentamethoxyfalavone, 3,5,6,7,3',4' - hexamethoxyflavone and 5,7,8,

4'- tetramethoxyflavone were isolated from its peel (Chkhikvlshvili et a/.,1993).

The major constituent of the volatile oil reported is limonene (65-94%) and

other constituents are V’terpinene (2.1-17.3%); p-cymene (0-2-8.2%), a-

49

pinene (0.3-2.5%); p-pinene (0.9-2.1%); sabinene (0.4-2.1%); terpinolene

(0.2-1.1%); myrcene (1.2-7.6%); linalool (0.03-6.1%); a-terpineol (0.03-1.1%);

dimethyl anthram'late (0.9%) (Ranganna e/a/.,1983); citropten. camphene, 3-

carene, a-and p-phellandrene, a-terpene, D-limonene from the mandarin oil

(Ashoorf and Bernhard, 1967), citral and citronellal (Wl, 1992). Myrcene,

nonanal, decanal, carvone, geranial, p-copaene, sabinol, 4-methy.

acetophenone, hexylhexanonate, y -selinene and bisabolene. Citrantin,

isolated from the peel was found to prevent pregnency in rabbits (Macleod et

a/.. 1988),

The leaves and young shoots of C. reticulata on steam distillation, yield an

essential oil known commercially as petitgrain oil. The reported volatile

constituents in the petitgrain oil are dipentene, +a-pinene (38.91%); linalool, +

dl-a-terpineol (28.61%), citral (3.7%) and citropten (1.87%) (Zaidi & Gupta,

1961). Total 22 compounds were identified and major compounds were y-

terpinene (20.15), p-cymene (16.29) linalool (9.55) and terpene-4-ol (7.13) in

leaf oil of Nigerian C. reticulata (EI<undayo ef a/.,1990). Citrosamine isolated

from leaves (Steward and Wheaton. 1968), 7-hydroxy-5,6,3',4' -

tetramethoxyflavone and 3'-hydroxy-5,6,7.8,4'-pentamethoxyflavone were

also Isolated from Its leaves (Mizuno et a/., 1987). The seeds of C.reticulata

are reported to have linoleic acid, palmitic acid, oleic acid, linolenic acid and

stearic acid, where as linoleic acid is the major fatty acid present in seed oil

(Ranganna et a/., 1983; Chaliha a/., 1963). 17-p-D- glucosides of limonene,

nomilin, deacetylnomilin, obacunone, deacetylnomilinic acid and ichangin

were isolated from its seed (Ozalei et a/., 1991). Major fatty acids palmitic

(12.1 - 28%). oleic (26.1- 45.3%), linoleic (29-38%), and other fatty acids

included stearic and linolenic acid in seed oil of Nigerian plant (Azewole and

Adeyeye, 1993). sitosterol (34.4%), campesterol (24.2%), stigmasterol

(18.1%) and cholesterol (3,1%) determined by GC-MS in roots (Douglas and

lllman, 1985), 2,2 -dimethyl pyranoflavonol, citmsinol, elemol, suberosln.

50

suberenol, crenulatin, xanthyletin. Xanthoxyletin, nordentatin. citropone A, 5-

hydroxy noracronycine, citrucinlne I, cilracridone I and p-hydroqulnone have

been reported in root bark (Wu, 1987).

p-Cymene^^Terpineol

CHO

Citronellal Myrcene

Camphene

51

HaH3CO

l-5Hydroxyauranetin I'Auranetin

R’H3C

CH, ;h3

R 0R 0I. Auranetin ,R = R' = HII. 5 - HydrojQ auranetin, R = OH; R'=H I- Citromitin, R = OCH3

III. 5 - 0 - Desmethyl nobiletin, R = OH; R' = OCH3 H- 5 - 0 - desmethyl citranfiitin. R =0HIV.Nobeletin,R = R' = OCH3

V.Tangeretin,R = 0 CH3:R' = H

HO-

Sabinene

-CH(0 H)CH2 NHMe* HOAc

ATerpinolene

Bisabolene

s

“ ■Pinene

Selinene

V

P“Pinene

52

0Citropten

Limonene

CHO

H3c / ^ C H 3Neral

H3C O

Scopoletin

OCH2CH = C(CH3)2

Imperatorin

Umbelliferone

Pmralenes

I.7- hydroxy - 3', 4', 5 , 6 - tetramethoxyflavone Ri = OH, R2 = OH. R3 = OCH3

II. 3' - hydroxy - 4', 5,6 ,7,8 - pentamethoxy flavone

Ri =R2 = OCH3. R3 = OH

53

OH OCitrusimol

HOOH

C -C H 2 - CH2 y -O C H a

OH o

NeohesperidinOH

OH

OCH

OH o

HesperetinOH O

Naringenin

Chemical constituents reported from Citrus reticulata

Rutinoside

54

Medicinal Uses

The fruit peel is used as stomachic, aromatic carminative and flavouring

agent. It is added in the preparation of orange tincture. Fresh rind Is rubbed

on the face as remedy for acne. Fruit peel oil is used in the manufacturing of

perfumes, soaps and flavouring extracts, and as a drug. As a flavouring

agent, it is generally recommended in non-alcoholic beverages, alcoholic

beverages, ice-creams, candy, backed goods, chewing gum, gelatins and

puddings, condiments, cereals, meats, syrups, etc. Orange squashes and

concentrates, (santra squash), which are prepared from juice extracted from

tight -skinned as well as from loose - skinned oranges, by use of automatic

juice extractors, are available in the market as soft drink preparations and are

widely used in summer season (Wealth of India, 1992).

Polysaccharides containing galacturonic acid showed anti-allergic activity

(Maeda et a/.,1991). Effects of quercetin, texifolin, nobiletin and tangeretin

were studied on in vitro growth of human squamous cell carcinoma H.T.B cell

culture were tested each flavonoid with different concentration (2 .0 to 8 .0

|ig/ml) for 3 to 7 days. Nobilitin and tangeretin markedly inhibited cell growth

at all concentration where as quercetin and taxifolin exhibited no inhibition in

any concentration (Kandaswami et a/.,1991), further study shows that

tangeretin and nobiletin markedly inhibited proliferation of squamous cell

carcinoma (HTB-43) and gliosarcoma (9L) cell line at different concentration

(2.0 to 4.0 M.g/ml), where as quercetin had no effect on 9L cell growth where

as at 8 ng/ml, it Inhibited HTB-43 cell growth. Taxifolin inhibited HTB-43 cell

growth at 8 .0 |ig/ml and moderately at 2.0 to 8 .0 ^g/ml.

The peel oil showed good anti-fungal activity against Aspergillus nidulans

(Eidam) Wingate, A. nigervan Tiegh, Cladosporium herbarum (Pers.) Link

ex. Fr. and Fusarium oxysporum Schlecht. ex. Fr. (Gupta and Singh, 1983).

55

Chapter 3

CITRUS RETICULATA BLANCO

EXPERIMENTAL & DISCUSSION

EXPERIMENTAL

Materials and Methods

Fresh plant material, fruits peel of C. reticulata was collected from the

cultivated species grown in the farmhouse located at Mahrauli, New Delhi.

Extraction and Isolation of Volatile Oil

The fresh plant material, fruits, (2.0 kg) was taken and hydrodistilled in an all

glass apparatus according to the method recommended in the British

Pharmacopoeia, 1988. The colourless oil was dried over anhydrous sodium

sulfate and stored at 4'’C in the dark. The yield was 3.5 % based on the fresh

weight of the orange peel.

GC Analysis

Analytical GC was canied out on a Varian 3300 gas chromatograph fitted with

a silicone DB-1 capillary column (30 m x 0.25 mm), film thickness 0.25 (xm;

carrier gas Na, flow rate 1.5 ml/mln, split mode; temperature programmed 80-

250"C at 4®C/min. Injector temperature 250'’C, detector used FID, detector

temperature 300°C. Injection volume for all samples was 0.1 il,

GC-Mq Analysis

Analytical GC-MS was canied out on a Shimadzu QP-2000 Instalment at 70

eV and 250°C. GC column Ulbon HR-1 equivalent to OV-1, fused silica

capillary 0.25 mm x 50 m with film thickness 0.25 micron. The initial

temperature was 100®C for 6 minutes and then heated at the rate of 10®C per

minute to 250‘*C. Carrier gas was helium; flow rate 2 ml per minutes, detector

used was FID.

Identification of Components

The volatile components were identified by comparing their retention times of

GC and chromatograph with those of literature. Further identification was

achieved by GC-MS. The fragmentation patterns of mass spectra were

56

compared with those of in the spectometer data base using the NBS 54 AL

and Wiley L-build-in libraries and with those reported in the literature

(Jennings and Shibamato, 1980; Swigarand Silverstein, 1981; Adams, 1995,

Libey, 1991; Vermin and Petitjean, 1982; Andersen and Falcone, 1969).

Discussion

The components of the oil, the percentage of each constituent and the

retention time are summarised in Table 3.1, whereas the eight peak index of

the volatile constituents are tabulated in Table 3.2.

The components are arranged in order of GC elution on Ulbon HR-1

equivalent to OV-1 and DB-1. Approximately, 16 components detected in the

oil, out of which 12 constituents comprising 73,4% of oil, were completely

identified. The oil was characterised by large amount (72.9%) of

monoterpenes. Among 8 monoterpenes, five of them were hydrocarbons

(71.3%) and three were alcohols (1.6%). I-Limonene (59,6%) was the

predominent monoterpene followed by p-myrcene (4.1%), a-terpinolene

(3.5%) and p-pinene (3.2%). Only one sesquiterpene, germacren-4-ol,

occurred in trace amount in the sample. There were three non terpenic

constituents amounting 14.2%. The main non terpenic constituent was bis (2-

ethyl hexyl)-1,2-benzene dicarboxylic acid ester. About four components

(12.8%) remained unidentified in the sample. Earlier the amount of l-limonene

was reported in the range of 65-94% in orange fmit. However, l-limonene

occurred in 59.6% in our findings. 1,4-Terpineol, 2-nonyl-1-ol, cyclodecanoi

and germacren-4-ol are reported for the first time in orange peel. The earlier

reported components y -terpene, p-cymene, sabinene, linalool and dimethyl

anthranilate could not be detected in the Delhi sample. The monoterpenic

constituents, camphene, 3-carene, a- and p-phellandrenes, y-terpinene and

p-cymene were characterized in the C. reticulata of California and could not

be identified in the sample of Delhi region.

57

Table 3.1, Percentage composition of Volatile oil of C. reticulata fruit

peel.

S.No. Components GC-MSRT-1

GLCRT-2

% Area Method

1. a-Pinene 8.23 19.15 0.9 A,B

2 . p-Pinene 9.53 21.93 3.2 A.B

3. l-Llmonene 11,76 25.09 59.6 A,B

4. p-Myrcene 12.16 25.45 4.1 A.B

5. a-Terpinolene 13.16 27.74 3.5 A.B

6. f-Pinocarveol 14.60 29.85 0.5 A,B

7. 1,4-Terpineol 15.86 32.05 0.5 A,B

8 . a-Terpineol 16.26 32.62 0.6 A, B

9. n-Nonyl-1-ol 16.50 0.2 A

10. Cyclodecanol 17.53 36.40 0.2 A. B

11. Gemiacren-4-ol 18.83 0.1 A.B

12. Unknown 32.93 - 0.3 A

13. Bis (2-ethyl hexyl)-1.2 - benzenedicarboxylic acid ester *

37.43 * 13.8 A

14. Unknown 39.66 - 0.3 A

15. Unknown 43.06 - 8.0 A

16. Unknown 55.60 - 4.2 A i

RT -1 = Retention time on ULBON HR -1 column equivalent to OV -1.

RT - 2 = Retention time on SILICON DB-1 on capillary column

A = GC - MS Analysis

B = GC Analysis

58

Table 3.2. Eight Peak Index of Volatile Constituents of C. reticulata

fruit peel

S.N

Name,

MolecularFormula,

Molecularweight.

Chemical Structure Mass fragmentation Index

01a-PineneCioHieMW=136 y

93 (100), 91 (45.6)41 (40.2). 77 (38.0), 92 (38.0), 79 (29.3), 43 (15.2), 53(15.2).

02p-PineneCioHi6MW=136

KI y

41 (100), 69 (41.3),93 (39.1), 43 (16.3), 91 (9.8), 44 (9.8), 53 (9.5), 67 (9.2).

03l-LimoneneCioHieMW=136

c>r68 (100), 66 (77.1), 93 (52.1), 41 (40.2), 53 (33.7), 79 (32.6), 94 (20.6), 77 (19.5).

04P-MyrceneCioHieMW=136

93 (100), 91 (51.0), 77 (42.4), 43 (36.4), 41 (29.3), 79(26.1), 92(23.9), 136 (23.3).

05 a-Terpinol-eneCioHi6IVIW=136

41 (100), 43 (98.6), 71(98.6), 55 (70.6), 93 (52.1), 69 (42.4), 80 (26.1), 67(21.7).

59

06f-PinocarveolCioHieOM W =152

U O H41 (100), 69 (46.7). 55 (33.7), 43 (26.6). 67(20.1), 95 (19.0), 56 (17.4), 68(11.9).

071,4-Terpineol Cio Hi8 O MW = 154

71 (100), 43 (87.4), 41 (47.8), 93 (35.8), 55 (32.6), 111 (28.2), 69 (21.7), 67 (20 .6).

08a-Terpineol CioHieO MW =154

59 (100), 43 (55.9), 93 (35.8), 41 (27.2), 81 (26.1), 121 (21.7), 67 (17.9), 136 (14.1).

09n-Nonyl-1-ol

CgHieO

MW = 142

CHa (CH2)7CH20H41 (100), 43 (77.6), 84 (47.8), 55 (39.1), 67 (34.8), 83 (34.2), 57 (33.7), 68 (29.3).

10CyclodecanoIC10H20O MW = 156

^ (C H 2 )3 " \ OH 41 (100), 69 (50.0), 55 (26.6), 67 (34.8), 83 (34.2), 57 (33.7), 6 8 (29.3).

11Gemnacren-4-0IC15H24O MW =220

82 (100), 41 (87.4), 67 (34.8), 68 (34.2), 69 (34.2), 54 (27.7), 53 (22.6). 83 (21.2).

60

12Unknown 149(100), 57(92.9), 43(56.5),

71(44.0), 41(43.2),167(35.6), 55(25.0),70(25.0).

13Bis (2-ethyl hexyl) -1 .2 . benzene discarboxylic acid ester C26H38O4 MW = 390

C y-COOCHj-CH-C^Hg

COOCHj-CpH-C Hg C2H5

149(100), 57(47.8), 43(37.5), 167(32.6), 41(30.4),71(29.9), 70(25.0), 55(23.9).

14Unknown 149 (100), 57 (77.1), 43

(62.4), 41 (45.6), 71 (42.1), 167(38.0), 55(25.5), 70 (26.1).

15Unknown 149 (100), 67 (51.0), 43

(38.6), 71 (31.5). 167 (33.1), 70(26.1)41 (31.0), 55 (18.5).

16Unknown 149 (100), 57 (64.6), 43

(53.2), 41 (43.4), 71 (37.5), 70 (31.0), 167 (30.4), 55 (24.4).

61

chapter 3

CITRUS RETICULATA BLANCO

SPECTRA & REFERENCES

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63

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