Glycosides are compounds that contain a sugar component (glycone) bonded to a non-sugar component (aglycone). Upon hydrolysis, glycosides break down into these components. Glycosides are widely found in plants and some are used medicinally as laxatives, cardiotonics, or expectorants. Examples discussed include senna, rhubarb, cascara sagrada, and aloe, which contain anthraquinone glycosides that act as stimulant laxatives. Glycyrrhiza (licorice) contains saponin glycosides and is used as a demulcent, expectorant, and tonic.

1. GLYCOSIDES & GLYCOSIDE-CONTAINING DRUGS
 Glycosides are group of chemical compounds which upon hydrolysis give rise to one or more
sugars and a compound which is not a sugar.
 The non-sugar component is known as the aglycone & the sugar component is called the glycone.
 The most frequently occurring sugar is -D-glucose, although rhamnose, digitoxose, cymarose,
and other sugars are components of glycosides.
 The non-sugar may be an alcohol, phenol, cyanohydrin or complex fused ring or heterocyclic
hydroxy compounds.
Example: Vanilla, Senna, Digitalis etc.
 Chemical constituent:
Chemically, the glycosides are acetals or sugar ethers in which the hydroxyl of the sugar is condensed
with a hydroxyl group of the non-sugar component, and the secondary hydroxyl is condensed within the
sugar molecule itself to form an oxide ring.
Sugar(glycone)+ non-sugar(aglycone) Glycoside
R-OH+H-O-X R-O-X+H2O
C6H11O5OH+HOC6H4CH2OH C6H11O5-O-C6H4CH2OH+H2O
 Properties:
1.Most of the glycosides are colourless, crystalline compounds
Exception: Anthracene glycosides are red or orange coloured compounds and flavone glycosides are
yellowish in colour.
2. They are soluble in water and alcohol, but insoluble in other organic solvents like petroleum ether,
solvent ether, chloroform etc.
3. Glycosides are optically laevorotatory.
 Classification:
1.On the basis of linkage of sugar molecule to aglycone, they are divided as follows:
(a) O-glycosides: In these glycosides the sugar is combined with alcoholic or phenolic hydroxyl function
of aglycone: e.g. digitoxin.
(b) N-glycosides: In these glycosides nitrogen of amino group (—NH2/—NH—) is condensed with a
sugar, e.g. nucleoside.
(c) S-glycoside: These glycosides contain a sugar moiety attached to a sulphur of the aglycone, e.g.
isothiocyanate glycosides.

2. (d) C-glycosides: Condensation of a sugar directly to a carbon atom gives rise to C-glycosides, e.g. aloin,
and cascaroside.
2.On the basis of nature of sugars:
Glycoside Sugar Example
a.glucosides glucose prunasin
b.fructoside fructose licoumarin
c.rhamnosides rhamnose scillaren
3. Pharmacological classification of glycosides:
a. laxative: senna, aloe, rhubarb, cascara sagrada
b. local irritant: Isothiocyanate
c. analgesic: methyl salicylate
d. cardio active: Digitalis & Strophanthus
4.Chemical nature of aglycone:
Glycoside Aglycone part Example
STEROIDAL STEROL
FLAVONOID FLAVINOID

3. ANTHRACENE ANTHRACENE
CYANOPHORIC CYANOGEN
TRITERPENIC TRITERPENE
Glycyrrhetinic acid
ALCOHOL ALCOHOL
Salicin
LACTONE LACTONE
ISOTHIOCYANATE ISOTHIOCYANATE
Sinigrin

4. SAPONIN SAPONIN
ALDEHYDE ALDEHYDE
 Functions of glycosides:
1. Digitalis and Strophanthus contain cardiac glycosides and are used as cardiac stimulant drugs.
2. Anthraquinone glycosides, present in Senna, Cascara, Rhubarb and Aloe, are used as laxative.
3. Picrorhiza roots and rhizomes possess picroside glycosides and are utilized as bitter tonic and to
protect damaged liver.
4. Wild Cherry bark and Scilla glycosides have expectorant properties.
5. Sinigrin, a glycoside of black mustard, is non-Irritating in It’s natural form, but on hydrolysis a
powerful irritating substance.
6. Act as a growth regulator of plant.
7. Protect plants from insects & other animal.
 Biosynthesis of glycosides:
 General process:
Consideration of glycoside biosynthesis necessarily consists of 2 parts. The general reactions couple a
sugar residue to an aglycone. Presumably this transfer reaction is similar in all biologic systems.
Available evidence indicates that the principal pathway of glycoside formation involves the transfer of a
uridylyl group from uridine triphosphate to a sugar 1-phosphate. Enzymes catalyzing this reaction are
referred to as uridylyl transferases. The subsequent reaction, mediated by glycosyl transferases involves
the transfer of the sugar from uridine diphosphate to a suitable acceptor (aglycone), thus forming the
glycoside.
Step-1: UTP+Sugar-1-P uridylyl transferases
UDP-Sugar+PPi
Step-2: UDP-Sugar+Acceptor glycosyl transferases
Acceptor-Sugar(Glycoside)+ UDP

5.  In case of Prunasin:
ANTHRAQUINONE GLYCOSIDE
 Anthraquinone glycosides possess anthracene or their derivatives as aglycone.
 The glycosides are found in the drugs like Senna, Aloe, Rhubarb, Cascara, Cochineal, etc.
 Properties:
 Anthraquinone derivatives are usually orange-red compound
 Soluble in water or dilute alcohol
 When the alcoholic or ethereal extract of powdered drug is treated with ammonia or caustic soda
solution, a pink, red or violet color is formed.
 Application:
 the anthrquinone aglycones in free state exhibit little therapeutic activity.
 act as stimulant cathartics
 increase the tone of the smooth muscle in the wall of large intestine.

6. SENNA
Source & naming :
 Senna or senna leaves consists of the dried leaflet of Cassia acutifolia known in commerce as
Alexandria senna, or of C. angustifolia known in commerce as Tirtnevelly senna .
 The name Senna is from the Arabic sena, the native name of the drug; Cassia is from the
Hebrew qetsiah, meaning to cut off, and refers to the fact that the bark of some of the species
was once peeled off and used & acutifolia is Latin and refers to the sharply pointed leaflets;
and angustifolia means narrow-leaved.
 Family: Leguminosae
Habitat : Egypt and neighbouring region for Alexandrian Senna; Tinnevelly Senna is cultivated in South
India in Tinnevelly, Madurai, Trichinopoly, Mysore; in N.W. Pakistan and Jammu.
 Collection: Alexandrian Senna
The plant is a small shrub bearing paripinnate compound leaves.
The plant grows well above 10°C
The plants require bright sunshine and occasional drizziling
When the leaves are fully grown and are thick and bluish in color, they are stripped off by hand before
flowering
The leaves are spread out on a hard floor to dry in shade.
The pods and large stalks are separated by means of sieves.
The color changes to yellow.
Leaves are graded
Packed under hydraulic compression into balls
Sent to the market.
Tinnevelly Senna
grown on dry or wet conditions
The leaves are gathered by hand

7. dried in the sun
Leaves are graded according to their size and colour of the leaflets,
compressed into bales
exported
 Chemical Constituents :
 Senna contains dianthrone glycosides: sennosides A, B, C and D.
 aloe-emodindianthrone-diglycoside,
 rhein-anthrone-8-glycoside,
 rhein-8-diglycoside
 aloe-emodin-8-glucoside and
 aloe-emodin-anthrone diglucoside
 In addition to these two naphthalene glycosides: 6-hydroxymusizin glycoside and tinnevellin
glycoside have been isolated
 Senna also contains flavonoids like kaernpferol, its glucosides (kaempferin), isorhamnetin: a
sterol and its glucoside, mucilage, calcium oxalate, resin and free anthraquinones.
 Uses:
 Senna is used as purgative and cathartic.
 It is stimulant laxative
 The drug is used in acute constipation and in all cases in which defaecation with a soft stool is
required:
 with haemorrhoids
 after anal-rectal operations
 before and after abdominal operations
 with anal fissures, for the evacuation of X-ray contrast media from intestines

8.  Disadvantages:
 There may be reddening of urine (harmless)
 passage of some of the anthracene derivatives into mother’s milk which may cause
diarrhoea in infants
 Overdose may lead to colicky abdominal pains and the formation of thin, water stools
RHUBARB
 Biological Source : Rhubarb is the dried rhizome and roots of Rheum officinale & R. palmatum.
 Rheum is from the Latin Rha, the name of the Volga River near which species of Rheum grow.
Palmatum refers to the large spreading leaves.
 Family : Polygonaceae.
 Habitat : China, Tibet, Nepal, Central Asia; cultivated in Europe, southern Siberia, and North
America.
 Chemical Constituents :
 Rhubarb contains free anthraquinones and their glycosides (3-12%) such as chrysophanol,
aloe-emodin, emodin, physcion and rhein.
 Anthrones or dianthrones
 The dianthrone glucosides of rhein (sennosides A and B) and the oxalates of these
(sennosides E and F)
 Besides these, Rhubarb contains glucogallin, free gallic acid, (-)-epicatechin gallate, catechin,
rheotannic acid, erythroretin, methylchrysophanic acid, rhubarberon, cinnamic acid and calcium
oxalate.
 Uses:
 Rhubarb is used as a stomachic,laxative; in larger doses as a purgative.
 Rhubarb has been used in cathartic preparations;
 used in treatment of diarrhoea.

9. Cascara Sagrada
 Synonyms: Purshiana bark, Bearberry bark.
 Biological Source : Cascara is the dried bark of Rhamnus purshiana
 Family : Rhamnaceae.
 Habitat : Cascara is grown on the Pacific coast of North America, British Columbia, Oregon,
Washington, California and Kenya.
 Collection :
The bark is collected during April-August from 6-12 meters high tree.
The bark Is removed from the tree by making longitudinal incisions.
The trees are often felled and the bark is separated from larger branches.
It is dried in the shade or in sun by keeping cork upper side.
The bark is stored by protecting from rain and damp.
The dried bark is cut into small pieces.
 Chemical Constituents:
 Cascara contains anthracene derivatives :O-glucosides (10-20%) and C-glucosides (80-90%)
 free anthraquinones.
 Cascarosides A, B, C and D
 Two aloins: barbaloin and chrysaloin
 A number of glycosides derived from emodin, emodin oxanthrone, aloe-emodin and
chrysophanol.
 Users:
 Cascara is purgative and generally used in the form of liquid extract, elixir or tablets prepared
from a dry extract.
 Cascara sagrada is a cathartic.
 Its principal use is in the correction of habitual constipation
 in veterinary purpose

10. ALOE
 Biological Source : Aloe is dried juice of the leaves of Aloe barbadensis
 Family : Liliaceae.
 Habitat : There are about 180 species of Aloe and most of them are found in South Africa and
West Indies. Native of Northern Africa but it is planted in Indian gardens and many other tropical
countries.
 Collection :
The Aloe leaves contain spines at the margins.
the leaves are cut in March-April In V-shaped
a vessel is kept under the Incision.
The juice is evaporated in copper vessel on open fire
poured into cans or tins
allowed to solidify
exported
 Chemical Constituents :
 Aloe contains a mixture of crystalline glycosides known as aloin. The principal constituents of
aloin are barbaloin, isobarbaloin, β-barbaloin, aloe-emodin and resins.
 In addition to these, flavonoids, oxanthraquinones, coumarins, amino acids, monosaccharides,
polysaccharides, oils, sterols, triterpenes, vitamin C and group B vitamins, citric, L-malic and
formic acids are present in aloes.
 Uses:
 Aloe is used as purgative
 given in constipation.
 It is one of the ingredient of Compound Benzoin Tincture,
 Ointment of aloe-gel is used to cure burns caused by heat, sun or radiation and skin irritations.
 to cure many skin diseases, ulcerative skin conditions, wounds, burns, snake bite,
 as hair tonic,
 to treat enlarged spleen
 tonic for stomach and brain
 as a febrifuge and emmenagogue to relieve buring sensation.

11. SAPONIN GLYCOSIDES
 Upon hydrolysis they yield an aglycone known as a “sapogenin”
 Saponins are highly complex glycosides which are widely distributed in the higher plants like
Glycyrrhiza.
 properties:
 Saponins have a high molecular weight
 their isolation in a state of purity presents some difficulties
 Saponins form colloidal solutions in water that foam upon shaking
 they have a bitter, acrid taste
 They destroy red blood corpuscles by hemolysis and are toxic, especially to cold-blooded
animals.
 Many saponins are used as fish poisons
 Uses:
 possess demulcent and expectorant, tonic, laxative, emollient properties
 added to chewing gums, chocolate candy, cigarettes, smoking mixtures, chewing tobacco, and
snuff
 facilitate absorption of poorly absorbed drugs, such as the anthraquinone glycosides.
 used in genito-urinary diseases, coughs, sore throat
GLYCYRRHIZA
Synonyms : Liquorice; Licorice: Liquorice root; Sweetwood
Biological Source : Glycyrrhiza consists of the dried unpeeled roots and rhizome of Glycyrrhiza
glabra.
Family : Leguminosae.
Habitat : The drug is found from southern Europe to central Asia in Iran, Iraq, Russia, Arabia,
Afghanistan, Turkestan, Asia Miror, Greece and Siberia.
Cultivation:
The plant is a 1 m high perennial herb.
in well moist sandy soil in March
planting rhizome or stolon cuttings
grows better near the banks of river in sunny climate.
Manure is added for favourable growth

12. Collection:
Drug is collected from 3-4 years old plants during autumn.
Roots and rhizomes are dug out
rootlets and buds are removed
washed in water
cut into small pieces.
Chemical constituent:
 Glycyrrhiza contains 6-14% of glycyrrhizin (the glucoside of glycyrrhetic acid), sugars and resin.
 flavonoids like isoliquiritin ,liquiritin, liquiritigenin, isoliquiritigenin
 The other constituents are liqcoumarin (5-15)% of sugars (glucose,mannitol, sucrose), asparagine
β-sitosterol, starch , protein, bitter principles, umbelliferone (coumarin), malic acid and resin.
Uses:
 Glycyrrhiza possesses tonic, laxative, demulcent, diuretic, emmenagogue and emollient
properties
 used in genito-urinary diseases, coughs, sore throat
 as demulcent, in inflammatory affections or irritable conditions of the bronchial tubes
bowels and catarrh;
 to relieve peptic ulcer pain.
 Glycyrrhiza is added to chewing gums, chocolate candy, cigarettes, smoking mixtures,
snuff and chewing tobacco.
 Glycyrrhetinic acid is used to cure rheumatoid arthritis, Addison's disease and various
inflammatory conditons.
 It is used considerably as a flavoring agent and is frequently employed to mask the taste
of bitter drugs such as aloe, ammonium chloride, quinine.

13. CYANOGENETIC OR CYANOPHORE GLYCOSIDES
 Properties:
 on hydrolysis yield hydrocyanic acid
 they are derivatives of mandelonitrile
 most widely distributed of these is amygdalin & prunasin
 The sugar residue of the molecule may be a monosaccharide or a disaccharide which is
attached to oxygen atom of aglycone
 Found in apricots, cherries, peaches, plum.
 Uses:
 widely employed as flavoring agents.
 Anticancer claims have also been made for an amygdalin-containing preparation
 control of sickle cell anemia
 The hydrolysis of amygdalin & prunasin takes place in 3 steps, which briefly are as follows:
1. The molecule is hydrolyzed initially to liberate 1 molecule of glucose and 1 molecule of
mandelonitrile glucoside.
2. The second molecule of glucose is liberated with the formation of mandelonitrile.
3. The mandelonitrile then breaks down with the formation of benzaldehyde and hydrocyanic
acid.
H2O, Prunase

14. WILD CHERRY BARK
 Wild Cherry bark Is the dried stem bark of Prunus serotina
 Family : Rosaceae.
 The plant is a tree that grows in the eastern United States and Canada. The commercial supplies
of the drug come chiefly from Tennessee, Mississippi, Virginia, and North Carolina
 Chemical Constituents :
 Wild Cherry bark contains a cyanogenic glycoside
 prunasin
 enzyme prunase,
 benzoic acid,
 trimethylgallic acid,
 p-coumaric acid,
 starch, tannin and volatile oil.
 Uses:
 used in cough preparations as sedative & expectorant
 as flavouring agent.
ISOTHIOCYANATE GLYCOSIDES
 Isothiocyanate glycosides contain sulphur and present In many Cruciferous plant
 On hydrolysis they produce isothiocyanate aglycones which may be aliphatic or aromatic.
 Sinigrin from Black Mustard, sinalbin from White Mustard and gluconapin from Rapeseed
are isothiocyanate glycosides.
 Sinigrin on hydrolysis in the presence of the enzyme, myrosin, yields allyl isothiocyanate,
glucose and potassium acid sulphate.

15.  Uses:
 These glycosides are irritant and employed as counter-irritant externally in neuralgia and
rheumatism.
MUSTARD
Mustard is the dried ripe seed of Brassica nigra or of B. juncea
Family: Cruciferae.
Habitat : Europe, U.S.A., southwestern Asia, India & abundantly cultivated in upper Indian
region.
Chemical Constituents :
 Mustard contains fixed oil (30-35%),
 proteins (20%),
 sinigrin (0.7-1.3)%
 myrosin,
 sinapine & sinapine sulphocyanate,
 erucic acid, behenic acid and sinapolic acid
Uses:
 Black mustard is a local irritant
 Commercially, it is used as a condiment
 It acts as emetic in large doses.
 used in the form of plasters, as rubefacient, vesicant.
Cardiac Glycoside
o These are steroidal glycosides
o show highly specific and powerful action upon the cardiac muscles.
o Cardenolides the aglycone part
o glucose, rhamnose, digitoxose and cymarose are the sugars usually attached to the aglycone.
o The sugar part is attached at C-3 position of the steroidal nucleus
o These compounds are present in Digitalis, Strophanthus, Oleander, Calotropis and Convallaria.

16.  Uses:
 The use of the cardiac glycosides in therapeutics stems from the ability of these
compounds to increase the force of systolic contraction & decrease the heart rate
 to treat congestive heart failure, atrial fibrillation, atrial flutter.
DIGITALIS
 Synonyms :Foxglove; Purple foxglove; Fairy gloves: Digifortis; Digitora.
 Biological Source :Digitalis consists of dried leaves of Digitalis purpurea
 Habitat : Southern and Central European countries, England, Germany, Holland, France,
Northern U.S.A. and in Kashmir
 Cultivation:
soil consisting of equal parts of clean sand, garden soil, manure and leaf mould
stained seeds are sown in a soilin March
after about two months the seedlings are transferred in fields.
 Collection:
Leaves of the first year crop contain maximum amount of active constituents.
The leaves are collected in the early afternoon from September to November by hand.
The leaves are dried immediately after collection below 60°C.
Dried leaves are packed in air-tight containers.
Silica gel or calcium oxide is placed in the container to absorb moisture.
 Chemical Constituents :
 additional compounds: tannins, inositol, luteolin, acids, fatty matters, antirhinic acid,
digitalosmin, digitoflavone and pectin

17.  Digitalis contains about 35 glycosides and some of these glycosides are given below
 Uses:
 Digitalis is used as a cardiac stimulant and tonic.
 The drug stimulates cardiac muscles, increases the systole of heart ventricle and
normalizes the heart frequency.
 the drug is useful in congestive heart failure, atrial flutter and atrial fibrillation.
STROPHANTHUS
 Biological Source : Strophanthus is the ripe seeds of Strophanthus kombe or S. hispidus.
 Family: Apocynaceae.
 Habitat: East and central Africa.
 Chemical Constituents :
 Strophanthus contains a cardiac glycoside strophanthin-K (2-5%),
 glycoside: ouabagenin
 kombic acid,
 choline,
 trigonelline,
 fixed oil (30%),
 resin and
 mucilage.

18.  Uses:
 Strophanthus is used as cardiac tonic,
 diuretic and arrow poison.
SQUILL
 Synonyms : Sea onion; Bulbus Scillae: Meerzwiebel, Scilla bulb
 Biological Source: Squill consists of the dried sliced scales of the fleshy inner bulb of the white
variety of Urginea maritima & Scilla maritima
 Family : Liliaceae.
 Habitat: Mediterranean seacoasts of Spain, France, Italy, Greece, Algeria, Morocco; Algiers and
Cyprus.
 Chemical Constituents :
 The drug contains:
 scillaren A,
 scillaren B.
 glucoscillaren A,
 proscillaridin A,
 scillaridin A.
 scilliglucoside
 scil1ipheoside,
 glucoscillipheoside.
 scillicyanoside,
 scillicoeloside,
 scilliazuroside and
 scillicryptoside.
 also contains:
 flavonoids like quercetin derivatives
 kaempferol polyglycosides;

19.  sinistrin,
 mucilage and
 calcium oxalate.
 Uses:
 used as expectorant,
 diuretic, and cardiotonic,
 tshows emetic action.
ALDEHYDE / PHENOLIC GLYCOSIDES
Vanilla
 Source: full-grown, unripe fruit of Vanilla planifolia
 Vanilla is from the Spanish vania, a sheathlike pod, and illa, meaning small; planifolia is from
the Latin planus, meaning flat, and folium, meaning leaf;
 Family: Orchidaceae
 The plant is native to the woods of eastern Mexico but is cultivated in tropical countries, Java,
Indonesia, Madagascar.
 Chemical constituent:
 two glycosides: glucovanillin and glucovanillic alcohol,
 Vanillin is the principal flavoring constituent.
 also contains about 10% of sugar, 10% of fixed oil, and calcium oxalate.
 Uses:
 Vanilla, in the form of vanilla tincture, is used as a flavoring agent and
 as a pharmaceutical aid.
 It is a source of vanillin.

20. TANNINS
Hamamelis Leaf
 Hamamelis leaf or witch hazel leaves is the dried leaf of Hamamelis virginiana
 Hamamelis is from the Greek hama, meaning same time, and melis meaning a fruit;
virginiana indicates that the plant is found in Virginia
 Family: Hamamelidaceac
 The plant is found in Virginia, although the actual habitat ranges from New Brunswick to
Minnesota and extends southward to Florida and Texas.
 Chemical constituent:
 hamamehtannin
 hexose sugar
 volatile oil
 bitter principle,
 gallic acid and
 calcium oxalate.
 Uses:
 hamamelis water is nevertheless widely utilized for its so-called astringent properties
 It is incorporated in hemorrhoidal products, preparations for treating insect bites and
stings,
 in teething preparations.
Mixed Glycosides
SAFFRON
 Saffron is the dried stigma and style-tops of Crocus sativus
 Family: Iridaceae.
 Geographical Source: The drug is native of south Europe and is found in Spain. France,
Macedonia, Italy, Persia. Austria, China, Germany, Switzerland and Iran. In India the plant Is
cultivated In Kashmir.
 Chemical Constituent:
 carotenoid coloured compounds crocin & picrocrocin
 crocetin
 geritlobiose
 α-and β-carotene
 volatile oil & fixed oil
 Uses:
 as coloring and flavouring agent.
 used in fevers, cold, and enlargement of the liver
 in snake bite, cosmetics and pharmaceutical preparation

21.  as spice.
 Saffron has stimulant, stomachic, tonic, aphrodisiac, sedative properties
 also used for preparing saffron cake
SANTONICA
 Also called Santonica flower
 Santonica consists of the dried unexpanded flower heads of Artemisia maritima
 Family: Compositae.
 Santonica is found in Turkestan, Pakistan, Iran, Tibet, Nepal and India.
 Chemical Constituents:
 α-santonin (24%),
 volatile oil (2-3%),
 artemisin & resin.
 Uses:
 Santonica is anthelmintic
 santonin is more effective on roundworms than threadworms.
 It is used as deobstruent, stomachic, laxative and tonic
 used to treat intermittent and remittent fevers.
GENTIAN
 Gentian is the dried rhizome and roots of Gentiana lutea
 Family: Gentianaceae.
 Habitat: Central and Southern Europe, Asia Minor, Pyrenees.
 Chemical Constituents :
 Gentian contains the bitter glycoside gentiopicrin (~2%) as a principal active Constituent.
 gentisin,
 gentiopicroside,
 amaropanin,
 amarogentin,

22.  amarosweri
 also contain:
 starch,
 trisaccharide ,
 gentianose,
 disaccharide gentiobiose,
 sucrose,
 alkaloid gentianine,
 yellow pigment gentisin,
 gentiamarin,
 gentisic acid,
 tannins,
 pectin and
 calcium oxalate.
 Uses:
 Gentian is used as a bitter tonic and stomachic for increasing appetite and
 to cure debility.