This document discusses glycosides, which are organic compounds derived from the replacement of a hydrogen atom of a cyclic hemiacetal by an organic radical. Glycosides are obtained from plant or animal sources and contain a sugar moiety (glycone) and non-sugar moiety (aglycone or genin). Important examples discussed include digitoxin, a cardiac glycoside used to treat congestive heart failure, sennoside which is a laxative anthraquinone glycoside, and diosgenin which is a steroid sapogenin extracted from yams and used to synthesize progesterone and cortisone. The document also covers classification, structures, properties and tests for various types of glycosides

1. Glycosides
Dr.N.Gopinathan M.Pharm Ph.D
Assistant Professor
Faculty of Pharmacy
Sri Ramachandra
Medical college and Research institute ( Deemed University)
Chennai, Tamilnadu India.

2. • They obtained from plant or animal
sources.
• Upon acid or enzymatic hydrolysis
yield one or more sugar moieties
along with non sugar moiety.
• The sugar moiety is called glycone.
• The non sugar moiety is called
aglycone or genin

3. • Many plants store important chemicals in
the form of inactive glycosides.
• The most important clevage enzymes are
the glycosidic hydrolases and synthetic
enzyme is glycosyl transferases.
• If a glycone group is glucose, then the
molecule is glucoside
• Fructose – Fructoside
• Glucuronic acid - Glucuronide

4. Definition
• Organic compounds derived by the
replacement of the hydrogen atom of
the cyclic hemiacetal by an organic
radical.

5. • The hydroxyl group that is derived
from carbonyl group by ring
formation [C1 in aldoses and C2 in
ketoses] is involved in glycoside
formation this hydroxyl group is
known as Glycosidic hydroxyl group.
• The organic radical linked at
glycosidic hydroxyl group is acid
labile.

6. • A completley methylated glycoside is
hydrolysed by acid , only the glycosidic
methoxy group is hydrolysed, while
remaining methoxy group are not
affected

7. • The nature of the organic radical
attached at the glycosidic hydroxyl
group can be established by acidic
hydrolysis.
• The physiochemical and therapeutic
properties of glycosides depend on the
aglycone part.
• The sugar moiety helps for the
transportation of aglycone portion to
the site of action.

8. It exist in two anomeric forms called α and β

9. Glycoside , a sugar bonded through its
anomeric carbon to another group via
• Oxygen – O – glycosidic bond
• Carbon – C – glycosidic bond
• Sulphur – S- Glycosidic bond
• Thioglycoside
• Nitogen – N- glycosidic bond
• Glycoscylamine

10. Types of Glycosidic bond
• Depending on whether the glycosidic
bond lies above or below the plane of
the cyclic sugar molecule, the glycosides
are classified as α or β.
• Some enzyme α amylase can only
hydrolyse α linkages.
• Emulsin can only affect β linkages.

11. Classification
• 1. Alcoholic glycosides:
• Salicin is converted into salicylic acid in the
body.
• It is closely related to aspirin and as
analgesic, antipyretic and antiinflammatory
effect.

12. 2.Anthraquinone glycoside
• A glycoside present is a derivative of
anthraquinone.
• It is present in senna , rhubarb and
aloes.
• They have laxative effect.

13. 3.Coumarin Glycoside
• A glycone is coumarin Eg. Apterin –
dilate coronory arteries as well as block
calcium channels.

14. 4.Cyanogenic glycoside
• A glycone contain a cyanide group.
• The glycoside can release the poisonous
hydrogen cyanide. Eg. Amygdalin from
almond.
• Cyanogenic glycosides can be found in
fruits [ includes cherries, apples, plums ,
almonds , peaches , apricots and
raspberries ]

15. • Therefore it has to be washed and
ground under running water prior to
consumption.
• Sorghum expresses cyanogenic
glycosides in roots and thus it is
ressistant to pests such as root
worms.

16. 5. Flavonoid Glycoside
• A glycone is Flavonoid
• Eg. Hesperidin , Ruitin

17. 6.Phenolic glycoside
• Aglycone is simple phenolic structure
• Eg.Arbutin – urinary antiseptic

18. 7. Saponin Glycoside
• It gives permanent froth when shaken
with water.
• Haemolysis of RBC.
• Saponin found in liquorice –
expectorant effect

19. 8.Steroidal Glycoside
• Cardiac glycoside – Aglycone is steroidal
nucleus.
• Treatment of heart disease.

20. 9. Steviol Glycoside
• Sweetness from 40-300 times sweeter
than sucrose.

21. 10.Thio Glycoside
• It contains sulphur
• Sinigrin found in black mustard.
• Sinalbin found in white mustard.

22. Keller-Kiliani test
• Specific for glycosides with 2 des
oxy sugars.
• Glycoside dissolved in glacial acetic
acid containing a trace of ferric
chloride and conc.H2SO4.
• The acetic acid layer turns blue.

23. Legal test
• A solution of silver diammine ion
indicates the presence of butenolide
ring.
Baljet reaction : Cardenolide with alkaline
picrate solution gives orange colour

24. Digitoxin

25. • It is cardiac glycoside.
• Congestive heart failure treatment
• C10H64O13
• 17 th position lactone ring
• Steroid nucleus.
• 14 beta hydroxy is belived to be
dispensible

26. • If A/B Cis is converted into A/B trans
Activity will be dropped.
• Steroid nucleus with a unique set of
fused rings, which makes these
agents easily distinguished from the
other steroids.
• Ring A/B and C/D are Cis fused
where B/C is trans.

27. • This type of ring fusion gives
aglycone nucleus of cardiac
glycoside the characteristic U
shape.
• It also carries the two angular
methyl group at C10 & C13.
• Hydroxyl group is located at C3,
the site of sugar attachment.

28. • Hydroxyl group is located at C14 is
normally unsubstituted.
• The additional OH group is found at
C12 and C16 eg Digitoxigenin,
digoxigenin and gitoxigenin.
• The additional OH group have
significant impart on the
partitioning and pharmacokinetics
for each glycoside.

29. • The lactone ring at C17 is another major
structural feature.
• The size and degree of unsaturation of
the lactone ring varies with source of
glycoside.
O
O

30. Plant origin have cardenolide, possess α,β
unsaturated lactone ring varies with
source of glycoside.
Animals origin have bufadienolide possess
six membered pyranone ring with two
conjugated double bonds [α pyranone ]
O
O
O
O

31. Sugars
• The hydroxyl group at C3 of the
aglycone is usually conjugated to a
monosaccharide or a poly
saccharide with β 1,4 glucoside
linkages.
• The most commonly found sugars
are D-glucose, D- digitoxose, L-
rhamnose and D- Cymarose

32. • The sugar predominately exist in the
cardiac glycoside in the β conformation.
• In some cases sugar existed in the
acetylated form.
• 17 Lactone plays an important role in
receptor binding.
• Unsaturation in the lactone ring is
important saturation cause diminishes
in the activity

33. Lactone was replaced with open chain
structures of varying electronic and
steric resemblance to the lactone ring
showed the fact that α,β unsaturated
lactone ring at C17 was not an
absolute requirement and that several
α,β unsaturated open chain groups
could be replaced with little or no loss
in activity.

34. • Analogs possessing an α,β
unsaturated nitrile at C17
had high activity.
• The glycoside linkage is
always β in the case of D-
sugars and α in the case of
L - sugar

35. Digitoxin
• It is derived from Digitalis
• Digitalis –latin word – digitus –
meaning relating to finger.
• A group of pharmacological active
compound are extracted mostly
from the leaves of the second years
growth.
• Brand name : Crystogin and lanoxin

36. • The two drugs differ in digoxin has an
additional hydroxyl group at C-3 position
on the B ring Both molecules include a
lactone ring and a triple repeating sugar
called a Glycoside.

37. Sennoside
O
COOH
O
HOOC
O
O
O
O
O
O
O
O
O
O

38. • It is an hydroxy anthracene
glycosides derived from senna
leaves.
• It first stimulates colon activity and
they speeds bowel movements.
• It increases the fluid secretion by
the colon

39. Sapogenin
O
O
O

40. Fusion of rings

41. Sapogenin
• The saponins [ latin sapo- Soap ] are
glycosides which lowers the surface
tension of water.
• The genin portion may be
pentacyclic triterpene C30
sapogenin or a c27 steroidal
sapogenin with a spiroketal side
chain [ spirostane ]

42. • Penta cyclic triterpene sapogenin with a
spiroketal side chain are distributed in
plant kingdom.
• It is used as fish poison owing to their
detergent properties.
• Fish killed by saponins are edible as
ingested saponins

43. Diosgenin
• It is steroid sapogenin .
• It is extracted from the tubers of
Dioscorea wild yam.
• Its aglycon is used in commercial
synthesis of progesterone, Cortisone
and steroidal product.