Introduction to saponin glycosides, Saponin glycosides, Properties of saponin glycosides, Types of saponin glycosides, chemical tests of saponin glycosides

1. Saponin glycosides
Prepared by,
Ms. M.S. Divya Sree,
Assistant Professor,
Department of Pharmacognosy,
Sree Vidyanikethan College of Pharmacy, Tirupati,
Andhra Pradesh

2. A group of plant glycosides known as
saponins share in varying degrees, two common
characteristics:
(a) They foam in aqueous solution.
(b) They cause haemolysis of red blood cells.
The aglycones of the saponins are
collectively referred to as Sapogenins.
The more poisonous saponins are often
called Sapotoxins.

3. Properties
 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.
 Enhace the absorption of other drugs.

4.  Saponins form colloidal solution in water (hydrophilic
colloids) which froths upon shaking. These substances
modify and lower the surface tension and therefore form
foam when shaken. This has led to their use to increase
the foaming of beer.
 Practical industrial applications of saponins include their
use in cleaning industrial equipment and fine fabrics and
as powerful emulsifiers of certain resins, fats and fixed
oils.

5.  In general, they have a bitter, acrid taste.
 Characteristic for all saponins is their ability to cause
haemolysis of red blood corpuscles and to destroy them.
When injected into the blood stream, they are highly
toxic.
 When taken by mouth, Saponins are comparatively
harmless, being not absorbed from the intestinal tract.
 Saponins have a high molecular weight and their
isolation in a state of purity presents some difficulties.

6. Structure of saponins
According to the structure of the aglycone or sapogenin,
two kinds of saponin are recognized:
1. The steroidal type (commonly tetracyclic triterpenoids,
C-27).
2. The triterpenoid type (pentacyclic triterpenoids, C-30).
• Both of these have a glycosidal linkage at C-3 and have a
common biosynthetic origin via mevalonic acid and
isoprene units.

7. Steroid skeleton3
25
26
27
1
18
19
21
17
Pentacyclic triterpenoid skeleton
23 24
25 26
27
28
29 30
3
1

8. A. Steroidal saponins
 The steroidal saponins are less widely distributed in
nature than the pentacyclic triterpenoid type.
 Steroidal saponins are of great pharmaceutical
importance because of their relationship to compounds
such as the sex hormones, cortisone, diuretic steroids,
vitamin D and the cardiac glycosides.
Examples: Diosgenin (Dioscorea sylvatica), Sarsapogenin
(Smilax sp.).

9. B. Pentacyclic triterpenoid saponins
• Triterpenoid saponins my be classified into three
groups represented by -amyrin, -amyrin and
lupeol.
Examples: Glycyrrhetinic acid (Glycyrrhiza sp.)
Primulagenin (Primula sp.) and Quillaiac acid
(Quillaia saponaria).

10. E
D
Amyrin Amyrin Lupeol
20
19
1713
14

11. Chemical tests
• Haemolysis test - a drop of blood on slide is mixed
with few drops of aqueous Saponin solution, RBCs
becomes ruptured in presence of saponins.
• Foam test - to 1gm of drug add 10-20 ml of water,
shake for few min, formation of froth about 2 cm
high that persists for 10 minutes or longer.