SAPONINS

Definition of saponins Classification of saponins Distribution, localization and function Uses Physical characters Methods of preparation Quality control Storage Chemistry Saponins containing drugs from medicinal plants and

their medical uses

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Learning Objectives

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The student should be able to cover

Definition and structure of saponins and glycosides drugs.

Extraction, characterization and quantification of saponins

drugs.

Structural and biological properties of saponins drugs.

Official names, synonyms, biological sources,

identification, chemical constituents, uses, precautions,

adverse reactions, contraindications and toxicity of some

selected drug containing saponins.

Learning Outcomes

4

Pharmacognosy by W.C. Evans. Trease and Evan’s, 12th edition.

London. Page Number 23-153; 170-205; 250-289.

Pharmacognosy Phytochemistry by Jean Bruneton, Medicinal Plants

(1999) Page Number 5-73; 91-256; 312-345

Pharmacognosy and Pharmacobiotechnology (1996) by Page

Number 1-40; 59-121.

Phytochemical Methods, J. Harborne PDR for Herbal Medicines

2nd edition 30-75; 77-156.

Organic Chemistry by IL Finar Page Number 368-473; 170-205;

250-289

References

Saponins are a class of chemical compounds, one of many

secondary metabolites found in natural sources

Saponins found in particular abundance in various plant species.

They are amphipathic glycosides grouped, in terms of

phenomenology, by the soap-like foaming they produce when

shaken in aqueous solutions

In terms of structure, by their composition of one or more

hydrophilic glycoside moieties combined with a lipophilic

triterpene derivative.

Saponins

Saponins

Plant constituent which bring about frothing in an aqueous

solution. Historically it is used for their detergent

properties.

Saponins is one type of glycosides

Saponins have haemolytic properties when injected into

the blood stream are highly toxic (used as an arrow

poisons).

When taken orally, saponins are harmless.

Two types of saponins are recognized

Pentacyclic triterpenoid Steroidal types.

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Saponins

Group of organic compounds that form persistent froth when shaken with water.

Saponins cause haemolysis of red blood cells.

The word Soap means Soap like.

Saponin Glycosides

Soluble in water, alcohol and mixture of

them.

Form persistent froth with water.

Used as detergent and emulsifying agents.

Aglycones are called Sapogenin.

Cause haemolysis of RBC’s if reach the

blood.

Form complex with cholesterol.

Only small part absorbed when taken orally.

Enhance the absorption of other drugs. 21-Jan-

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Properties

Saponins are hydrolyzed (by acids) to give an aglycone and

different sugars related to uronic acids.

Saponin Aglycone + Sugar

Aglycone called sapogenin (insoluble in water).

Structure of the sapogenin (aglycone) determines the type of

saponin (steroidal or tetracyclic triterpenoid and pentacyclic

types).

Both types of glycosides have a glycosidal linkage at C-3.

Both types of saponins have a common biogenic origin

(mevalonic acid and isoprenoid units)

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Saponins = Glycosides

Rare in monocotyledons

But abundant in dicotyledons.

Sapogenin is attached to a chain of sugar or uronic acid

units (or both) often in the C-3 position.

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Pentacyclic Triterpenoid Saponins

It is also called tetracyclic

triterpenoids

Found in many monocotyledons such as

Wild yam (Dioscorea vilosa).

Also found in dicotyledons fenugreek.

Strophanthus and Digitalis contain both

steroidal saponins (glycosides) and

cardiac glycosides.

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Steroidal Saponins

Generate much interest due to their

relationship with compounds such as

sex hormones, cortisone, diuretic

steroids, vitamin D and the cardiac

glycosides.

Some are used as starting materials

for the synthesis of these

compounds.

Diosgenin is the main sapogenin used

by industry . 21-Jan-

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Significance of Saponins

Test for Saponin Glycosides

Froth Test -Place 1ml solution of drug in water in a semi-micro tube and shaken well and noted for a stable froth.

Hemolysis test -Add 0.2ml solution of saponin (prepared in 1% normal saline) to 0.2ml of v/v blood in normal saline and mix well, centrifuge and note the red supernatant compare with control tube containing 0.2ml of 10% blood in normal saline diluted with 0.2ml of normal saline.

Normally maceration method is use for the extraction of saponins.

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Extraction of saponins

Water +Methanol

Plant materials

48 hours

Filter

Saponins

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Acetyl Co-Acetate (Acctyl-coA)

Hydromethylglycol-Co-acetate (HMG-CoA)

Mevalonic acid

Isopentenyl pyrophosphate (IPP)

Dimethylallyl pyrophophate (DMAPP)

Meva

lonic acid

path

way

. Gernyl pyrophosphate (GPP) Squalene

Steroidal Saponins

Biogenesis of Steroidal Saponins

OPPOPP

OPP

Mevalonic acid

Hemiterpenes (C5) DMAPP (C5) IPP (C5)

GPP (C10) Monoterpens & Iridoids (C10)

IPP

OPPFPP (C15) Sesquiterpenes (C15)

IPP

OPPGGPP (C20)

Diterpenes (C20)

2 x FPP Triterpenes (C30) 2 x GGPP Tetraterpens (C40)

Steroids (C18-C30)

squalene

Natural products serve as starting points for the partial

synthesis of commercial products.

Cortisone is synthesized from Hecogenin.

Sex horomones (oral contraceptives)–synthesized from

diosgenin.

Diosgenin can also be used to make corticosteriods.

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Natural Steroids for the Production of Pharmaceuticals

Corticosteriods

◊ Definition: Wild yam is

the underground roots and

tubers of Dioscorea

villosa.

◊ There is no suggestion

that the plant was used as

a contraceptive in the

past. Traditionally been

used to treat menstrual,

ovarian & labour pains. 21-Jan-

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Dioscorea villosa-Dioscoreaceae

Dioscorea villosa – Wild Yam

Steroidal saponins (mainly

dioscin)

Phytosterol,alkaloids,tannin

s, starch.

Actions

Anti-spasmodic anti-inflammatory anti-rheumatic Diaphoretic diuretic, qi tonic expectorant

In Zulu traditions, wild yam is

used to treat convulsions, epilepsy

and hysteria.

Also used for colic, dry cough,

depression, diarrhoea, diabetes,

emotional weakness, immune

weakness, IBS, leg pain, low

sperm count, lung weakness,

morning sickness, neuralgia, night

sweats, RA, senility,

spermatorrhoea, threatened

miscarriage.

Topically: salve for eczema,

poultice for bruises and scabies.

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Dioscorea villosa-Dioscoreaceae Constituents Other uses

Definition: Siberian ginseng

consists of the dried roots

and rhizomes of

Eleutherococcus senticosus.

This herb is better at

maintaining good health

rather than treating illness.

Traditionally been used to

treat Insomnia

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Eleutherococcus senticosus-Aralaiceae

Constituents

Triterpenoid saponins

Glycans

Polysaccharides

Coumarins

Lignins

Actions

Adaptogen

Tonic

Immune-modulator

Uses

Insomnia

Stress

Surgery Recovery

Chemotherapy patients

Cardiovascular disease

CONTRA-INDICATIONS

Continuous use

Hypertensive patients

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Siberian Ginseng –Eleuthrococcus

Definition: Ginseng consists

of the dried or fresh roots

of Panax ginseng. Also

called Korean or Asian

ginseng.

Traditionally it is used for

the treatment of appetite

loss

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Ginseng–Panax ginseng

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Medicinal Uses To Improve stamina, reaction

time, decrease high cholesterol.

Speeds up recovery time after

illness, childbirth and surgery.

Aids, Alzheimer’s, anaemia,

appetite loss, chronic fatigue,

depression, infertility, memory

loss, tacchycardia, PTSS.

Helps soften skin–anti-wrinkle

products.

Active Constituents:

Triterpenoid saponins

(ginsenosides), B vitamins,

selenium, phytosterols,

volatile oils.

Medicinal Actions:

Adaptogenic tonic, anti-

inflammatory, anti-oxidant,

anti-spasmodic, cardiotonic,

hepatoprotective, immune-

stimulant, nervine

Panax ginseng – Korean Ginseng

Leaves can be used for fever.

Effects – cumulative – work best

after a period of use, but should

not for excessive/continuous use.

Contraindications Should not be used if pregnant or

lactating.

Not to be used in cases of heat or

inflammation.

Should not be taken if suffering

from flu, fever, pneumonia,

constipation or hypertension. 21-Jan-

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Panax ginseng –Contraindications

Definition: Fenugreek consists of

the dried seeds of Trigonella

foenum-graecum.

Traditionally it is used for the

treatment of diabetes

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Trigonella foenum graecum– Fabaceae (Legume Family)

Active Constituents Steroidal saponins

(diosgenin, yamogenin), B

vitamins, alkaloids,

glycosides, flavonoids,

courmarin, mucilage.

NOTE: Should not be

used to treat diabetes

without professional

supervision.

Medicinal Actions

Anti-inflammatory, carminative,

antiseptic, emollient, expectorant,

hypoglycaemic, phytoeostrogenic.

Medicinal Uses

Stabilize blood glucose levels,

anorexia, catarrh, cough, sore

throat. Topically for boils, burns,

cellulitis, gargle for sore throats,

eyewash for inflammed eyes and a

facial wash.

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Fenugreek-Trigonella

Definition: Quillaja bark

consists of the dried inner

bark of Quillaja saponaria.

It is also called soup bark,

Quillaja or Panama wood.

Traditionally it is used for

emulsifying agent

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Quillaja saponaria –Rosaceae

Mixture of saponins (10%)

On hydrolysis: main

sapogenin Quillaic acid

and Gypsogenin.

Sapogenin Quillaic acid +

Gypsogenin

Also consists of sugars,

starch and calcium

oxalates.

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Quillaja Bark - Constituents

Used as an emulsifying agent.

It is used for the treatment

for various chest pain

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Quillaja Bark - Uses

Definition: Liquorice consists

of the dried unpeeled roots

and stems of Glycyrrhiza

glabra.

Traditionally it is used for

the treatment of ulcers

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Glycyrrhiza glabra - Leguminosae

Plants grow well in deep sandy, fertile soil.

The underground parts are collected in their 3rd-4th year.

Dug up & washed.

Some are peeled and cut shorter before drying; others are left unpeeled.

Imported in bales, or made into stick or block liquorice.

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Glycyrrhiza–Cultivation & Collection

Glycrrhizin – Responsible for the sweet taste.

Glycerrhizic acid – Triterpenoid saponin.

Flavonoids – Responsible for yellow colour.

Liquiritin – Chalcone responsible for yellow colour

Sugars (glucose and sucrose), protein & starch.

Glycyramarin – Bitter principles (mostly in outer tissue –removed in peeled varieties)

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Glycyrrhiza glabra -Constituents

Glycyrrhiza uralensis

Glycyrrhiza hirsutu

Glycyrrhiza echinata

Glycyrrhiza macedonia

Glycyrrhiza pallidiflora

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Glycyrrhiza glabra - Adulterants

Actions

Anti-microbial/anti-viral Anti-spasmodic Anti-Ulcerogenic Demulcent Expectorant

Uses

Flavouring agent RA Addison’s disease Inflammatory conditions Peptic ulcers

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Glycyrrhiza glabra Actions & Uses

Definition: Senega consists

of the dried rootstock and

root of Polygala senega.

Traditionally it is used for

the treatment of snake-

bite

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Polygala senega -Polygalaceae

Triterpenoid Saponins:

Main saponin – Senegin

Other saponins

Senegenin

Senegenic acid

Polygalic acid

Also contains

Sorbitol (sweet taste),

Sucrose,

Fat and

Sterols.

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Polygala senega – Constituents

White senega – Polygala alba

Southern senega –Polygala boykini

Pakistan senega –Glinus oppositifolius

Turkey senega – Polygala pruinosa

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Polygala senega - Adulterants

Actions

Stimulant expectorant

Uses

Chronic bronchitis

TRADITIONAL USES

First used by the Native American

Indians as a remedy for snake-bite.

It was later used by the English as

cure for pleurisy and pneumonia.

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Polygala senega - Uses

Definition: Gentian consists of

the dried, fermented roots and

rhizomes of the yellow gentian,

Gentiana lutea.

Traditionally it is used for

the treatment of Liver

disorders

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Genitana lutea - Gentianaceae

There is no demand for the unfermented ‘white’ gentian, all

commercial drugs consist of the fermented ‘red’ variety.

Herb is made into heaps, packed on a hillside and occasionally

covered with earth and left there for some time.

Washed and cut into slices.

Dried: Open air or oven.

When prepared this way, the herb becomes much darker in

colour (fermented), loses some of its bitterness and acquires a

distinctive odour. 40

Gentiana – Collection & Preparation

Main Chemical Constituents

Gentiopicroside

Gentiogenin

Other constituents

Glycosides

Alkaloids

Flavonoids

Sugars

Pectin and essential oil.

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Gentiana lutea - Constituents

Allied Drugs

Gentiana purpurea

Gentiana pannonica

Gentiana punctata

Gentiana kurroo

Picrohiza kurroo

Adulterants

Rumex alpinus

Veratrum album

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Gentiana lutea

Actions

Anti-microbial/anti-viral

Uses

Herbal tonic

Liver disorders

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Gentiana lutea - Uses

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