1. Glycosides are organic compounds found in plants and animals that contain a sugar (glycone) and non-sugar (aglycone or genin) portion. Upon hydrolysis, the sugar and non-sugar portions separate. 2. There are several types of glycosides based on the atom involved in the glycosidic linkage between the glycone and aglycone, including O-, C-, S-, and N-glycosides. 3. Two common cardiac glycoside drugs that contain glycosides are Digitalis and Aloe. Digitalis contains compounds like digitoxin and gitoxin that have cardiac effects. Aloe contains compounds like aloin that have laxative effects.

1. Introduction
• Naturally occurring organic compounds
• Found in both plants and animals
• On hydrolysis (by acids or enzymatic) gives one
or more sugar moiety (glycone) and non-sugar
moiety (aglycone).
• Non-sugar (aglycon) called genin.
• The pharmacological acivity is due to the
presence of genin part.
• Glycone part facilitates the transportation of
genin to the site of action.

2. Glycosides
Definition
These are the organic compounds obtained
from the plants or animals sources which on
enzymatic or acid hydrolysis gives one or
more sugar moieties along with non-sugar
moiety.

3. Glycosides
Enzymatic or acid hydrolysis
sugar moieties(glycone) non-sugar moiety
(aglycone or genin)

5. • The sugar involved in glycosides are of
different types, but most commonly, it is β-D
glucose. Other are galactose, mannose,
rhamnose, digitoxose, cymarose, etc.
• The linkage between alycone & aglycone is
called glycosidic linkage.

6. Types
1. Based on atoms involved in glycosidic linkage
• O- glycosides
• C- glycosides
• S- glycosides
• N- glycosides
2. According to chemical nature of aglycone part
• Cardiac/sterol glycosides-Digitalis, indian squill, strophanthus,
• Anthracene(Anthraqunone) glycosides-Senna, rhubarb,aloe,
cascara
• Cyanogenetic glycosides-Bitter almond, white cherry bark,
• Saponin glycosides-Dioscorea, liquorice, Ginseng,sersaparilla
• Isothiocynate glycosides-Black mustard

7. 1. According to linkage existing b/w
the glycone and aglycone
• All types of glycosidal linkages are occured by
interaction of –OH group of glycone and
hydrogen coming through any of the radicals
like –CH, -OH, -SH, and –NH present on
aglycone part. Hence, by elimination of one
water molecule, linkage or a bridge is formed
and the type of glycoside formed is named by
putting the element as prefix like-

8. 1. C-gylcosides
• Some of the anthraquinone glycosides such as
Cascarosides from Cascara and aloin from aloe,
as well as some member of flavone type of
glycosides show the presence of C-glycoside.
Glycone--OH+ HC--aglycone
Glycone--C--aglycone + H2O
• They are not hydrolysed by heating with dil.
Acid/alkalies but by oxidative hydrolysis with
ferric chloride.

9. 2. O-glycosides
• Common in higher plants.
• Examples-Senna, rhurbarb, etc
• They are hydrolysed by treatment of acid or alkali
into aglycone and sugar.
Glycone--OH+HO—aglycone
Glycone--O--aglycone
+
H2O

10. 3. S-glycosides
• Restricted to isothiocynate glycoside like-Sinigrin
from black mustard.
• They are formed by interaction of sulfahydryl
group of aglycone and hydroxide group of
glycone
Glycone--OH+HS—aglycone
Glycone--S--aglycone
+
H2O

11. 4. N-glycosides
• N-glycosides are nucleosides.
• The glycosides contain sugar but still the physical,
chemical and therapeutic properties are given by
aglycone part.
• Examples-Adenosine-antiarrythmic, yeast nucleic
acid- brewer's yeast(nutrient supplement)
Glycone--OH+HN--aglycone
Glycone--N--aglycone
+
H2O

12. Isolation Method
Stas-Otto Method
• The drug containing glycoside is finely powdered and the
powder is extracted by continuous hot percolation using
soxhlet apparatus with alcohol as solvent.
• Various enzymes-deactivate due to heating.
• The thermolabile glysosides, however, should be extracted at
temperature preferably below 45 degree centigrade
• The extract is treated with lead acetate to precipitate tannins
and thus eliminating non-glycosidal impurities.
• The excess of lead acetate is precipitate as lead sulphide by
passing hydrogen sulphide gas through solution
• The extract is filtered, concentrated to get crude glycosides.
• From crude extract , the glycosides are obtained in pure form
by making use of processes like fractional solubility, fractional
crystallization and chromatography techniques such as
preparative thin layer and column chromatography.

13. Anthracene Glycosides
• These constitute a major class of glycoside.
• They are mainly found in the dicot plant and
families like-Euphorbiaceae, Ericaceae,
Polygonaceae, Rhamnoceae, Rubiaceae,
leguminosae, Verbenaceae, etc.
• This group of glycosides comprises of different
aglycosides moieties like-anthraquione,
anthrone, anthranol, dianthranol and
dianthrone.

14. Anthracence derivatives

15. Borntrager’s Test

16. Glycosides containing crude drugs
• Cardiac glycoside-Digitalis,
• Saponins glycoside-Liquorice, Brahmi, Senega,
Ginseng
• Anthracene(Anthraqunone) glycosides-Aloe,
Rhubarb, Senna,
• Cascara
• Indian squill
• Strophanthus
• Dioscorea
• Gymnema

17. Digitalis
• Synonym-Digitalis leaves, foxglove leaves.
• Biological source- It consists of dried leaves of
Digitalis purpurea belonging to the family
Scrophulariaceae. The leaves should contain
not more than 5% of moisture.
• Geographical source- England, Europe, United
states & India.

20. Cultivation & collection
• It is biennial or perennial herb of about 1-2
meters in height
• It is propagated by seeds of selected strain,
containing high glycosidal content
• It needs calcarious, sandy, light soil with traces
of manganese
• The soil is sterilised by steam before sowing
• They grow in an altitude of 1600-3000m
• The seeds are mixed with fine sand and sown
in the nursery beds in March/April

21. • The young seedlings are transplanted in the
Sept. and Nov
• The crop is manured properly and kept free of
weed
• The plantation is done twice a year. In first
year, the plant bears rosette leaves and in the
second year sessile leaves
• The leaves are picked up in the afternoon
during Aug and Sept.
• The discoloured leaves are rejected

22. Preparation for market
• After the plucking the leaves are immediately
brought to drying centre and are dried in
vacuum driers at 60°C.
• The dried leaves(containing not more than 5%
of moisture) are packed into air tight
containers containing suitable dehydrating
agents.

23. Organoleptic characters
• Colour- dark greyish-green
• Odour-slight
• Taste-bitter
• Size-10-40cm long, 4-20cm width
• Shape-ovate-lanceolate to broadly ovate,
irregular margin.

24. Leaf morphology

25. Microscopic characters

26. Chemical constituents
• Digitalis contains 0.2 to 0.45% mixture of
cardiac glycosides(cardenolides)
• Purpurea glycosides-A and B which are primary
glycosides.
• Digitalis also contains other glycosides such as-
Odoroside-H, Glucogitaloxin, Gitaloxin,
Verodoxin and Glucoverodoxin.

27. Purpurea-A
Enzymatic hydrolysis
Digitoxin+ glucose
Hydrolysis
Digitoxigenin + digitoxin
Purpurea-B
Enzymatic hydrolysis
Gitoxin + glucose
Hydrolysis
Gitoxingenin + digitoxose

28. Chemical test

29. Uses
• Treatment of congestive cardiac failure
• It has a diuretic action
• Substitutes/adulterants:
-Leaves of Verbascum thapsus
-the primrose leaves
-comfrey leaves

30. Aloe
• Synonym-Aloe, kumari, musabbar, barbedense
• Biological source-Aloe is the dried latex of leaves
of various species of Aloes, Viz-
Aloe barbadensis, Aloe ferox, Aloe perryi, Aloe
africana belonging to the family Liliaceae
• Geographical source-West Indian island, cape
town, Europe, North-east Himalayan region in
India

33. Preparation
• The juice which exudes on cutting the leaves is
collected in goat or sheep skin. It is allowed to
evaporate spontaneously for a month. It
becomes a pasty mass.

34. MORPHOLOGY

35. Microscopic characters
Transverse section near the margin of an Aloe leaf, ep,-epidermis; gfb-vascular bundle, the
pericyclic cells, a-of which are much enlarged and contain a yellow secretion (aloes); p-
palisade; g-parenchyma; sp-stoma; cr-calcium oxalate crystals; m-mucilaginous parenchyma.

37. Chemical constituents
• Aloin A & B, D-glucoside, Aloe resin is a
mixture of three isomers- Barbaloin, β-
barbaloin & iso-barbaloin.

38. Identification test
• Preparation of test solution-
1g of aloe is boiled with 100ml of water and
cooled. Then 1g of Kieselghur is added, stirred
and filtered. This filtrate is used for the
following tests-
i) Schonteten’s test (borex test)- 0.5g of borex is
added to test solution and heated. This
solution when diluted produces a green
fluorescence.

39. ii) Bromine test- an equal volumn of test
solution and bromine solution are heated. A
pale yellow precipitate of tetrabromaloin is
produced.
iii) Nitro acid test- To 5ml of test aloe, add
crystals of sodium nitrate and acetic acid, it
gives pink colour

40. Uses
• Used as purgatives/laxatives
• Ointment of aloe gel for burns and skin
irritation
• Used as an ingredient of cosmetics
• Used as an ingredient of compound benzoin
tincture

41. • Substitutes/adulterants-
-Native aloes obtained from Aloe
candelabrum, mocha aloes, Jafferabed aloes.