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

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.

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.

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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 common biogenetic pathway ie.

mevalonic acid pathway.

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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

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 . 17-Jul-17 11

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 -

Biogenesis of Steroidal Saponins

Formed via the mevalonic acid pathway.

During this pathway, cholesterol forms part of numerous sapogenins (not all).

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Natural Steroids for the Production of Pharmaceuticals

Natural products serve as starting points for the partial synthesis of commercial products.

E.g. Cortisone – synthesized from Hecogenin.

Oral contraceptives –synthesized from diosgenin.

Diosgenin can also be used to make corticosteriods.

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Dioscorea villosa - Dioscoreaceae

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. It has, however traditionally been used to treat menstrual, ovarian & labour pains.

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Constituents Steroidal saponins

(mainly dioscin)

Phytosterols, alkaloids, tannins, starch.

Actions: Anti-spasmodic, anti-

inflammatory, anti-rheumatic, diaphoretic, diuretic, tonic, expectorant

OTHER USES

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,

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Eleutherococcus senticosus – Fam: Aralaiceae

Definition: Siberian ginseng consists of the dried roots and rhizomes of Eleutherococcus senticosus.

Unlike other medicinal herbs, this one is better at maintaining good health rather than treating illness.

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Constituents Triterpenoid saponins

Glycans

Polysaccharides

Coumarins

Lignins

Medicinal uses

Adaptogenic

Tonic

Immune-modulator

CONTRA-INDICATIONS

Continuous use

Hypertensive patients

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Ginseng – Panax ginseng

Definition: Ginseng consists of the dried or fresh roots of Panax ginseng. Also called Korean or Asian ginseng.

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Panax ginseng – Korean Ginseng 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, tachycardia,

Helps soften skin – anti-wrinkle

products. Leaves can be used for fever.

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

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Panax ginseng – Contra-indications

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.

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Trigonella foenum-graecum – Fabaceae (Legume Family)

Definition: Fenugreek consists of the dried seeds of Trigonella foenum-graecum.

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Fenugreek - Trigonella 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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Quillaja saponaria – Rosaceae

Definition: Quillaia bark consits of the dried inner bark of Quillaja saponaria.

It is also called Soap bark, Quillaia or Panama wood.

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Quillaia Bark - Constituents

Mixture of saponins (10%)

On hydrolysis: main sapogenin quillaic acid & gypsogenin.

Also consists of sugars, starch and calcium oxalates.

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Quillaia Bark - Uses Used as an emulsifying agent.

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Glycyrrhiza glabra - Leguminosae

Definition: Liquorice consists of the dried unpeeled roots and stolons of Glycyrrhiza glabra.

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Glycyrrhiza – Cultivation & Collection

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 (decoction).

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Glycyrrhiza glabra - Constituents

Glycrrhizin – Saponin responsible for the sweet taste.

Glycerrhizic acid – triterpenoid saponin.

Flavonoids – responsible for yellow colour.

Liquiritin – a chalcone

Sugars (glucose and sucrose), protein & starch.

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

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Glycyrrhiza glabra - Adulterants

Glycyrrhiza uralensis

Glycyrrhiza hirsutu

Glycyrrhiza echinata

Glycyrrhiza macedonia

Glycyrrhiza pallidiflora

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Glycyrrhiza glabra Actions & Uses Actions

Demulcent

Expectorant

Anti-microbial/anti-viral

Anti-spasmodic

Anti-ulcerogenic

Uses Respiratory Benefits

RA

Addison’s disease

Inflammatory conditions

Peptic ulcers

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Polygala senega - Polygalaceae

Definition: Senega consists of the dried rootstock and root of Polygala senega.

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Polygala senega – Constituents Triterpenoid Saponins

Main saponin – senegin

senegenin

senegenic acid

polygalic acid

Also contains sorbitol (sweet taste), sucrose, fat and sterols.

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White senega – Polygala alba

Southern senega – Polygala boykini

Pakistan senega – Glinus oppositifolius

Turkey senega – Polygala pruinosa

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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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Genitana lutea - Gentianaceae

Definition: Gentian consists

of the dried, fermented roots

and rhizomes of the yellow

gentian, Gentiana lutea.

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Gentiana – Collection & Preparation In Autumn the Roots are dug up in plants 2-5 years old.

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 and then in sheds.

When prepared this way, the herb becomes much darker in colour (fermented), loses some of its bitterness and acquires a distinctive odour.

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Gentiana lutea

Allied Drugs Gentiana purpurea

Gentiana pannonica

Gentiana punctata

Gentiana kurroo

Picrohiza kurroo

Adulterants Rumex alpinus rhizomes

(give a positive test for anthraquinones).

Veratrum album

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Constituents

Gentiopicroside and gentiogenin

Also bitter glycosides,

alkaloids, yellow colouring

matter, sugars, pectin and

fixed oil.

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Uses

Actions

Bitter

Uses

Bitter tonic

Liver disorders

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