Very Informative

1. CARDIAC GLYCOSIDES
• The genins or aglycones of all cardiac
glycosides are steroidal in nature
• May be referred to as steroid glycosides
• They act as cardiotonic agents

2. • Enhance the tone of the heart
• Excitability
• Contractibility of the cardiac muscle
• Also the improved circulation tends to
improve renal secretion.This relieves
oedema often associated with heart failure

3. Structural Characteristics of
Cardiac Glycosides
• This is always involved in a glycosidic
linkage to a mono, di, tri, or tetra
saccharide

4. • Most sugars that are found in cardiac
glycosides are uncommon deoxy-sugars
• E.g Digitoxose, Cymarose, Thevetose

5. C
CHO
C
C
C
CH3
OH
OH
OH
H2 C
CHO
C
C
CH3
OH
OH
H2
CHO
C
C
CH OH
H
C OCH3
OH
HCH3O
C OHH
CH3
Digitoxose Cyamarose Thevetose

6. O
R
OH
CH3
Sugar
Lactone ring
1
2
3
4
5
10
6
7
8
9
11
12
13
14
15
16
17

7. Types of cardiac glycosides
• The steroid aglycones or genins are of 2
types
• Cardenolides
• Bufadienolides

8. THE CARDENOLIDES
• They are more prevalent in nature
• Cardenolides are C23 steroids
• These have α,β-unsaturated 5-membered
lactose ring in position C-17
2 main types:
• Digitalis glycosides
• Strophanthus glycosides

9. O
R
OH
CH3OH
Sugar
1
2
3
4
5
10
6
7
8
9
11
12
13
14
15
16
17
O O
Cardenolides
Digitalis glycosides R=CH3
Strophanthus glycosides R=CHO OR CH2OH

10. The Digitalis group
These include:
• D. purpurea, D. dubia, D. ferruginea
• D. lanata, D. grandiflora, D. nervosa
• D. lutea D. mertonensis, D. subalpina
• D. thapsi

11. Chemical constituents
• digitoxin
• gitoxin
• digoxin

12. Digoxin
• Digoxin is the most widely used of
cardiotonic glycosides
• Obtained from the leaves of D. lanata

13. THE BUFADIENOLIDES
• This group of cardioactive agents includes
the following:
• Squill glycosides (scillarins)
• Toad poison (Bufotoxin)

14. Botanical source
• Obtained from the bulbs of varieties of
squill
• Family = Liliaceae

15. • Derives name from the generic name for
the toad (Bufo)
• Possesses doubly unsaturated 6-
membered lactone ring in position C-17
• Bufadienolides are C24 steroid

16. O
OH
R1
R2
Sugar
1
2
3
4
5
10
6
7
8
9
11
12
13
14
15
16
17
O
O
Bufadienolides
Squill glycosides R1=OH, R2=H
Bufotoxin R1 & R2 = ester group

17. Bufadienolides from Squill
• These glycosides include the following:
• Scillarin A
• Scillarin B
Uses
• A potent cardiotonic
• As expectorant specially in chronic
bronchitis

18. • As stimulant
• It is used as a very effective expectotant
both in asthma and chronic bronchitis
• It may possess anticancer
• Produces diuresis
• It causes emesis in relatively higher doses

19. • Chemical colour reactions have been
evolved to be used as the qualitative tests
either for:
• the various glycosides
• or their corresponding aglycones
TEST FOR CARDIAC
GLYCOSIDES

20. 1 Kellar-Kiliani
Test
The glycoside is
dissolved in glacial acetic
acid containing a trace of
FeCl3, add conc. H2SO4
along the side of the test
tube to settle at the
bottom (for deoxy sugars
e.g. digitoxose)
A reddish
brown colour
changing to
bluish green
colour appears
at the junction
of two reagents
within 2-5
minutes
spreading
slowly into the
acetic acid layer

21. 2. Kedde’s Test A solution of
glycosides is treated
with a small amount
of Kedde’s reagent
(Cardenolides)
Development
of a blue or
violet colour
that fades out
in 1- 2 hours
shows its
presence

22. MEDICINAL IMPORTANCE OF
CARDIAC GLYCOSIDES
• Cardiotonics
• Congestive heart failure
• Rheumatic heart disease
• Atherosclerosis
• Diuretics

23. Official Cardiac Drugs
• Digitalis leaf (digitalis tablets)
• Digitoxin tablets
• Digoxin injection