Cardiac Glycoside 

DEF- Cardiac glycosides are a class of organic compounds that increase the output force of the heart and decrease its rate of contractions by inhibiting the cellular sodium-potassium ATPase pump.

General structure-

The general structure of a cardiac glycoside consists of a steroid molecule attached to a sugar (glycoside) and an R group.[4] The steroid nucleus consists of four fused rings to which other functional groups such as methyl, hydroxyl, and aldehyde groups can be attached to influence the overall molecule's biological activity.[4] Cardiac glycosides also vary in the groups attached at either end of the steroid.

ð  All glycosides consists of an aglycone which is attached to one or more sugar (glycone) moieties.

ð  The Aglycone part have the pharmacological activity → Attached sugar moiety modify the solubility and Permeability.

ð  The Aglycone part consist of Cyclopentanoperhydrophenanthrene (Steroid) ring to which a 5 (Cardenolide) or 6 (Bufadienolide) membered unsaturated lactone ring is attached.

ð  One or more -OH or other substituents are present to the aglycone to determine its Polarity.


Example - Digitalis 


DIGITALIS

Biological Source

Plant Part – Dried leaves

Scientific Name – Digitalis pupurea

Family – Scrophulariaceae

 

Morphology

Colour: Dark greyish

Odour: odourless

Taste: Distinctly bitter

Length: 10 – 30 cm, Width: 4 – 10 cm

Shape: Ovate, Lanceolate, petiolate

 

Chemical Constituents

Primary glycoside:

-        Purpurea glycoside A and B



Secondary Glycoside:

-        Digitoxin, Digoxin



 

Primary glycosides are less significant than Secondary glycosides

Uses

1.     Used in treatment of Congestive Heart failure

2.     Preparation of Digoxin

3.     Treatment of articular fibrillation

 

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