saponins - جامعة نزوى · saponins are hydrolyzed (by acids) to give an aglycone and...
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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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