What are Glycosides?
• Organic molecules + sugar moiety (mostly monosacchrides)
• Definition: organic compounds, from plants & animal sources, which on
enzymatic or acid hydrolysis, give one or more sugar moieties (glycone)
with non-sugar moiety (aglycone-genin).
• Acetayls or sugar ethers
• Formed by –OH group of each of non-sugar and sugar moiety, with loss of
water, -OH group of aglycone maybe alcoholic or phenolic and in some cases
• Sugar involved in glycosides are of different types but mostly, beta-DGlucose.
• Classification of Glycosdies either of
o Chemical nature of aglycone part
o Therapeutic activity of aglycone part
o Linkage between glycone & aglycone
Classification of Glycosides
1. C-Glycoside: when sugar moiety is linked with Carbon atom
• E.g. Cascaroside of Cascara, Aloin of Aloe, Carminic acid of Cochineal
• Mainly present in Liliaceae family
• Not hydrolysed by heating with dilute acid/alkali, but by oxidative hydrolysis with
• Glycone – OH + H.C –aglycone Glycone –C-aglycone + H2O
2. O-Glycoside: when sugar moiety is linked with Oxygen atom
• hydrolysed by treatment of acid/alkali in to aglycone and sugar
• E.g glucoranillin
• Glycone –OH + HO -aglycone Glycone-O-aglycone + H2O
3. S-Glycoside: when sugar moiety is linked to sulphur atom
• Occurrence Iso-thiocyante glycoside (Sinigrin from Black mustard)
• Glycone –OH + HS-aglcyone Glycone-S-aglycone + H2O
4. N- Glycoside: when sugar moiety is linked to nitrogen atom
E.g. nucleoside, where amino group of base reacts with –OH group of
ribose/deoxyribose, ultimately gives N-glycosidic form
Glycone-OH + HN-aglycone Glycone-N-aglycone + H2O
Rhubarb, Aloe, Senna and Cascara- purgative-unknown chemistry before.
Vegetable & animal dyestuff –madder and cochineal
Similarity between: purgative drugs & dye stuff: apparent
Emodin-identified (aglycone-purgative drug-Rhamnus spp.)
Alizarine-identified (aglycone-dyestuff-madder plant)
Reduced anthraquinonesoxanthrone, anthrol , anthrone, union of two
Chrysophanol & chrysophanic acid: Rhubarb & Cascara
Aloe-emodin: Rhubarb & Senna
Rhein: Rhubarb & Senna
Emodin/Frangula emodin: Rhubard & Cascara
Synthesized either via acetate-malonate pathway or they are derived from
shikimate and mevalonate.
• Substitution at 1,8-dihydroxy.
• Derivative of anthraquinone Glycoside:
Dihydroxy phenol: Chrysophanol
Trihydroxy phenol: Emodin
Tetrahydroxy phenol: Carminic acid
Methyl group: chrysophanol
Hydroxymethyl group: Aloe-emodin
Carboxyl group: Rhein & Carminic acid
o Orange-red compounds (medullary rays of Rhubarb & Cascara)
o Usually soluble in hot water & dilute alcohol
o Detected by Borntrager’s Test
• Powder drug
• Macerate with immiscible organic solvent
(ether is recommended)
• To the Filtrate: aqueous ammonia or
• Pink/red/violet color
• Presence of anthraquinone derivative
• If only glycosides are present;
• First hydrolyzing with alcoholic
KOH or acid.
• When alkali is added to powdered
drug/section red color
produced served to locate
anthraquinone derivative in the
tissue (e.g. medullary rays of
cascara bark) .
• If drug contains either very stable
anthraquinone glycoside or
reduced derivative of anthranol
type , Borntrager’s test will be
Anthranols & Anthrones
Reduced anthraquinone derivative
Occur either free or combined as glycosides
Isomeric and one may be partially converted to the other in solution.
The parent substance, anthrone; pale yellow-non fluorescent substance and is insoluble in
Anthranol derivatives, brownish-yellow, forms a strongly fluorescent solution in alkali.
Anthranol derivative, found in aloe also have similar properties, strong green fluorescence
which aloe gives in borax or other alkaline solution has been used for identification test.
Anthranol & Anthrone, main constituents of chrysarobin, mixture of substance prepared by
benzene extraction from the material (araroba) found in the trunk cavities of the tree Andira
If a little chryasarobin is treated on a white tile with a drop of fuming nitric acid , anthranols
are getting converted into anthraquinone glycoside.
A drop of ammonia allowed to mix gradually with the acid liquid produces violet color.
This modification of Borntrager’s Test had been used for identity before underlying
chemistry was known.
• Intermediate product between anthraquinone and anthranols.
• They give anthraquinones on oxidation and fairbairn’s modification of the
Borntrager’s test accomplishes this by means of hydrogen peroxide.
• An Oxanthrone has been reported as a constituent of cascara bark.
• Derived from 2 anthrone molecules, which maybe identical or different.
• They readily form a result of mild oxidation of the anthrone or mixed
anthrones. (e.g. a solution in acetone and presence of atmospheric oxygen.)
• They are important aglycones in species of Cassia, Rheum and Rhamnus.
• Two chiral centers at C-10 and C-10’ are present in the dianthrones, and for a
compound having two identical anthrone moieties e.g. sennidin A, two
forms (the 10S, 10S’ and 10R, 10R’) .
• Occur in plants as their 1,1’-diglucosides.
Action is restricted to large bowel.
Hence the effect is delayed up to 6 h or longer.
The nature of peristaltic initiation is not known.
But derivative influence the ion transport across colon cells by inhibition
Source: dried roots of Rubia tinctorum
GS: Asia, Europe
Specification: not harvested before a minimum of 18 months & maximum of
2 months in order to get greater yield of dye.
• Constituents: anthraquinone glycoside chiefly: ruberythric acid
hydrolysisalizarin and primeverose
• Use: dyeing cotton, wool, linen, silk.
• Note: dyeing of cottton with alizarn originatd in India and subsequently
reached other countries including Turkey. It was dyed from hard water bath
containing alum as a mordant. The red color produced is quiet fast and
useful for dyeing.
• Source: dried female insect
Dactylopius coccus containing eggs and larvae
• Family: Coccidae, Order: Hemiptera
• GS: America, Caribbean island
• US-FDA approved color for food and drugs
• Constituents: 10% Carminic acid (red coloring matter-glucosidal
anthraquinone), 10% fat, 2% wax, Coccerin
• CT: carminic acid + water deep red color
as do + acid yellow-violet color
• Use: coloring agent for foods, drugs, cosmetic products, preparation of
lakes,inks, acid-base indicator, microscopic stain and in photography
• Carmic acid is used to prepare carmine.
• Syn: Kumari, Musabbar
• Source: dried juice of the leaves of Curacao-(Aloe barbadensis), Socotrine-(Aloe perryi),
Zanzibar-(Aloe ferox), Cape aloe-(Aloe spicata)
• Family: Liliaceae
• GS: africa, carribean island
• Meaning: aloe from arabic word viz. alloch: a shining bitter substance; vera: true;
ferox: wild; spicata: flowers in spikes; barbadensis: habitat of plant.
• Description: Leaves: sessile; apex: strong spine; lower portion: rounder & upper
portion: slightly concave
• Cultivation: root sucker are used; grow well even in poor grades of soils and in dry
climatic condition ; water logging near plant must be prevented; manure: N+P+K is
used; leaves are cut in 2nd yr of cultivation.; drug is obtained from leaves of 12 years.
• During collection of leaves; cut is given to leaves near their bases
Curacao aloe- Preparation
Barbados (Curacao) Aloe
V-shaped transverse cut at the base of flesh leaf
Place cut leaves in wooden troughs
Immediately placing in kerosene; due to spines on the leaves.
Then place in wooden troughs & kept in titled position to drain out all
• Boil the juice collected this way in large copper pans.
• During boiling latex evaporates, juice is further thickened.
• Thick juice is then poured into gourds or metal container where it
Cape aloe- Preparation
• Barbados (Curacao) Aloe
• Transversely cut leaves are arranged in a circular manner in the basin
• Dug in the ground which is lined either with goat skin or canvas.
• Leaves are placed in a such way so as to overlap the cut ends.
• Kept in this position for 5-6 hours, till all the juice exudes out and
collected in goat skin
• Collected juice is transferred to large iron kettle where it boiled and
stirred continuously with the help of a wooden paddle type
• When boiling juice attains a desired concentration, it is poured into
Socotrine & Zanzibar aloePreparation
• Socotrine Aloe
o The juice of leaves is collected in goat skin and allowed to
become semisolid in nature.
• Zanzibar Aloe
o The juice of this variety is poured into skins of some small
o Where it get solidifies and as such packed in wooden boxes
• Principal active constituent: aloin which is mixture of glucosides among
which barbaloin (aloe-emodin anthrone C-10 glucoside) is the chief
• Barbaloin is a C-glycoside and it is not hydrolysed by heating with dilute
acids or alkalis. Ferric chloride is decomposes barbaloin by oxidative
hydrolysis into aloe-emodin-anthrone, little aloe-emodin and glucose.
• Along with barbaloin, aloe also contains isobarbaloin, beta barbaloin, aloeemodin & resin.
• Aloeresin also responsible for purgative action of aloe.
1. Nitrous acid Test: crystals of sodium nitrite along with small quantity of
acetic acid are added to aqueous solution of aloe
Curacao aloe: sharp pink to carmine color
Cape aloe: faint pink color
Socotrine/Zanzibar aloe: very less change in color (due to isobarbaloin)
1. Nitric acid Test: either by directly applying nitric acid to drug or to its
Curacao aloe: deep brownish red color
Cape aloe: brownish color changing to green
Socotrine aloe: pale brownish-yellow color
Zanzibar aloe: Yellowish brown color
• Aloe is purgative; mainly on colon
• Ingredient of tincture of Benzoin (friar’s balsam)
• In cosmetics
Syn: St. John’s wort
Source: dried aerial parts of Hypericum perforatum
Family: Hypericaceae (Clusiaceae)
GS: Europe, Central Asia, Himalaya
History: flowering on June 24th –St. John’s day
o known in ancient Greece for anti inflammatory & healing property
o Meaning: hyper: above; icon (eikon)-picture: refers to practice of healing
• Anthraquinones: Hypericin ,Pseudohypericin, isohypericin &
• Use: used in treatment of anxiety & depression, used to lower
plasma concentration of the protease inhibitor
Syn: Sacred bark, Chittern bark
Source: dried bark of Rhamnus purshiana
GS: Pacific coast of North america
Bark stored for at least 1 year gave galenicals.
During storage its getting hydrolysed & change during storage.
Very bitter taste is reduced by treating it with alkali, alkali earth & magnesium oxide.
o 6-9% anthracene derivative (o-glycoside & c-glycoside)
o Cascaroside A, B, C, D
• Use: purgative, used in the form of liquid extract/tablet prepared from dry
extract, veterinary work
Syn: Goa Powder
Source: lysogenous cavity in the wood of Andira araroba
GS: Malabar coast
Form: Chrysarobin-a mixture of substance obtained by extraction with hot
• Constituents: Chrysaphanol anthranol (gives strong green fluorescence in
alkaline solution), emodin-anthrone-monomethyl ether
• Use: keratolytic agent, treatment of psoriasis, trichophytosis, chronic
eczema, skin disease
• Syn: Senna ki patti
• Source: dried leaflets of Cassia angustifolia (Indian-Tinnevelly),
Cassia acutifolia (Alexandrian )
• Family: Leguminosae
• Description: small shrub; 1 m high
• GS: TamilNadu, Africa
• Constituents: Sennoside A, BhydrolysisSennidin A,B
o Sennoside C,D
Color: Yellowish green
Odor : Slight
Taste: mucilaginous, bitter,
Indian senna leafs are bigger in
size compared to Alexandrian
epidermal cells have straight walls,
many contain mucilage
Both surface: scattered, unicellular,
Stomata: paracytic; spongy
• Soil: red loamy
• Sowing period: Feb-March & Oct-Nov
• Sowing method: broadcasting (by
• Earlier germination: seed surface is
abraded or triturated with sand.
• Avoided: High rain & water logging
• After 2-3 of sowing
• Harvesting: leaves in 3 steps
First Plucking: leaflet thick, green
Second: after 1 month
Third: after 4-6 weeks
• Sennoside content maximum at fully
grown, decreasing on maturation of
Collection & Preparation:
Sun Drying: branches bearing leaves
Separation by sieves of : pods & large
Tossed: shallow trays
Grading of leaves: sieve & hand
• Whole leaves
• whole leaves, whole leave-half
Packed somewhat loosely in bales
(cotton or paper)
• Chemical Test: Borntrager’s Test
1. Boil Drug + dilute H2SO4
3. Add to Filtrate: benzene (or ether or
4. Shake well
5. Separation : Organic layer
6. Add to Organic Layer: Ammonia
7. Color: pink-red color ( presence of
• Uses: purgative in perpetual constipation
• Allied Species:
1. Dog Senna: Cassia obovata
2. Palth Senna: Cassia auriculata
• Syn: Revandchini
• Source: dried rhizomes of Indian - Rheum emodi
Chinese - Rheum palmatum, Rhum webbianum
• Family: Polygonaceae
• GS: South east China, Tiber, Korea, India
• Collection & Preparation:
Wild plants, altitude more than 3000 meter, its must for growth.
Drought resistant plant; seed propagation by rhizome
Obtained from 6-10 year old plant; rhizome portion is dug up in spring or autumn
Aerial portion , dies in winter; rhizome remaining in ground regenerate in next spring.
Collected rhizomes, cleaned, decorticated and dried.
Larger rhizomes are cut Transversely or longitudinally.
Pieces are threaded by piercing a hole in them and such threaded pieces are dried under
shade.; some of the pieces are artificially dried.
• Drug is packed in wooden cases.
o Round pieces are prepared from small rhizomes which are cut only transversely and
hence they are barrel shaped.
o Shape: cylindrical or Conical; dimension: 8-10 cm length & 4 cm thickness
o Odor : Sharp; Taste: astringent; color: yellow surface and pale brown to red in color.
o Drug with pink fracture is regarded as high quality drug.
o Presence of start spots which indicates abnormal vascular bundle; appears as reddish
Anthraquinone with carboxyl group: Rhein & Glucorhein
Anthraquione without carboxyl group: aloe-emdin, emodin, chryasophanol, physcion
Anthrones & Dianthrones of alo-emodin, emodin, chryasaphanol and physcion
Heterodianthrone: Palmidin A, Palmidin B, Palmidin C
Astringent part mainly consists of Gallic acid as glucogallin, tannin, catechin &
o Rheinolic acid, pectin, starch, fast & Calcium oxalate
• Chemical Test:
o Rhubarb gives modified Borntrager’s test positive
o Rhubarb + alkali red color (due to anthraquinone glycoside)
Bitter stomachic, treatment of diarrhoea, purgative
Source: rhizomes of Rheum rhapontic
GS: Southern siberia and surrounding region of Volga river
Description: pinkish in color and shrunken in nature
Constituents: Rhaponticin-crystalline glycoside, derivative of stilbenediphenyl-ethylene
1. 0.5 g powder + 10 ml 45% alcohol for 20 minute shaking occasionally;
2. filter & press 1 drop of filtrate on filter paper
3. Examine under UV light
4. blue fluorescence in UV light
• Use: estrogenic activity
Iso thiocyanate Glycoside
• They are called as Glucosinates.
• Aglycone part of such glycoside contains isothiocyanate, as it contains
sulphur along with nitrogen.
• Widely scattered in family Cruciferae, Resedaceae, Capparidaceae.
• Contain enzyme Myrosinase
Syn: black or brown mustard, sinapsis
Source: dried ripe seeds of brown or black Brassica nigra or Brassica juncea
GS: Europe, US, India, USSR
Constituents: sinigrin (potassium myronate), myrosin enzyme,
o volatile oil, 90% allylisothiocyantae
o Seed: 27% fixed oil, 30% protein,
o mucilage, sinapine hydrogen sulphate
• Use: in the form of plasters, rubefacients
counter irritant, in large doses emetic, as an
• Source: dried seeds of Sinapsis alba
• Family: Cruciferae
• Constituents: glucoside sinalbin & myrosin.
o In presence of moisture decomposition takes place with formation of
isothiocyanate, sinapine hydrogen sulphate, glucose
o Isothiocyanate: pungent taste, rubefacient property
o Fixed oil, protein, mucilage
• Use: same as previous 1
Also termed as Cyanophore Glycoside
Derivatives of mandelonitrile
On hydrolysis yields Benzaldehyde & HCN, this changes Sodium picrate into Sodium
purpurate, color changes from yellow to brick-red.
Amygdalin bitter almond
Prunasin wild cherry bark
Phaseolunatin bean, Phaseolus lunatus hydrolysis prussic acid
First to discover cyanogenetic glycoside
Presence or absence of HCN was taxonomic importance and used it as a character for
separating the subfamilies of Rosaceae
1. Powder + water allow to moist
• Impregnate strip of filter paper neck of flask
• Treatment of filter paper with
o Sodium picrate: yellow gets converted to sodium isopurpurate (brick-red)
2. Freshly prepared Guaicum resin in absolute alcohol allowed to dry on filter paper
1. Wild cherry bark
Syn: wild black cherry, Virginian prune bark
Source: dried bark of Prunus serotina
GS: Canada, US
Maximum Pharmacological action during Autumn season.
Constituents: prunasin hydrolysis glucose + benzaldehyde, enzyme
prunase, hydrocyanic acid, benzoic acid, trimethylgallic acid, coumaric acid
o Tannin, resin hydrolysis scopoletin
• CT: 1) HCN liberated on hydrolysis reduces mercurous nitrate to metallic
• Use: syrup-tincture in cough preparation, mild sedative, irritable & persistent
2. Bitter almond
Syn: Amygdala amara
Source: dried ripe seeds of Prunus amygdalus
Constituent: chief-Amygdalin, 40-50% fixed oil, 20% protein, enzyme:
Amygdalin hydrolysis Benzaldehyde + HCN
HCN very toxic & makes the drug unsuitable for internal
Sweet almond do not contain amygdalin
Uses: Demulcent, Sedative due to HCN, perfumery industry & flavoring of
They are produced by higher plants, fungi & actinomycetes and exhibit broad range of
biological activities like fungicidal, antibacterial, insecticidal, phytotoxic and
In plants, they commonly occur in reduced & glycosidic form of 4-beta-D-glucoside of
On extraction & work-up or in the soil, compounds oxidatively converted to color
compounds like napthoquinone.
Biosynthesized by variety of pathway
Lawsone by shikimic-succinyl coA combined pathway.
Plumbagin by acetate-mevalonate pathway
Alkannin by shikimate-mevalonate pathway
Syn: Alkanet, Anchusae radix
Source: dried root of Alkanna tinctoria
GS: Hungary, South europe, Turkey
Constituents: alkannin, alkali sensitive ester of angelic acid, alkannan &
• CT: treatment of this extract with hydroxide gives a blue solution from which
a dye is precipitated by treatment with acid.
• Uses: coloring oils-tars, in tincture for the microscopical detection of oils-tars
Source: dried leaves of Lawsonia inermis
GS: North Africa,Egypt, India, Ceylon
Constituents: lawsone (coloring matter:hydroxynapthaquinone),
phenolic glycoside, coumarins, xanthones, quinoids, beta sitosterol
glucoside, flavonoids: luteoline
o Fats, resin, tannin
• Use: dye for hair, wool washed in dilute solution of ammonia and boiled in a
decoction of drug, treatment of jaundice, enlargement of the liver and spleen,
• Syn: apricot
• Source: dried fruits of Juglans regia,-Persian J.cinerea-Butter nuts, J.nigra-black
• Family: Juglandaceae
• GS: Asia, America
• Constituents: Juglone (5-hydroxy, 1,4 napthaquinone), glycosides of alphahydrojuglone in its reduced form brown dye juglone on extraction and
• Use: dyeing wool and cotton to yellowish brown color, although it no longer
has any commercial value as a dye. It is fungicide and also finds its use in the
treatment of skin disease, sunburn, scalp itching, peeling & dandruff.
• Note: used to detect the trace amounts of nickel salts since it gives a deep
violet color with such salts.
• Transfer of a uridylyl group from uridine triphosphate to a sugar 1-phosphate.
• Enzymes catalysing reactions are called as referred to a uridylyl transferase and
have been isolated from animal, plant and microbial sources.
• Glycosyl transferases involves the transfer of the sugar from uridine diphosphate
to a suitable acceptor aglycone, thus forming glycoside.
• UTP + sugar-1-P ---1--- UDP-sugar + Ppi
• UDP-sugar + acceptor ---2--- acceptor-sugar + UDP
Biosynthesis of anthraquinone
• By acetate mevalonate pathway or isochorismate alpha ketoglutaric acid
• Followed by polyketide
Biosynthesis of Aloe-emodin
Biosynthesis of Amygdalin
• Defense mechanism: ability to produce toxic amounts of HCN, which is
extremely toxic to most of the organism as it inhibits cytochrome oxidase and
other respiratory enzymes.
• Shikimic acid pathway.. Amino acid phenyl alanine.
• Amygdalin serves as a phagostimulant for malacosoma americana.
• (A natural plant substance that induces feeding by an insect.)
• Young fruits only contain prunasin, but after development, the cotyledons