Page 161 - phytochemistry I - PharmD Clinical

• Cardiac glycosides also exerts a diuretic activity. Since, the
improved circulation tends to improve renal secretion, which
relieves the edema often associated with heart failure.

Side effects and toxicity:

• From ancient times, humans have used cardiac-glycoside-
containing plants and their crude extracts as arrow coatings,
homicidal or suicidal aids, rat poisons, heart tonics, diuretics and
emetics, primarily due to the toxic nature of these compounds.

• Excessive cardiac glycoside dosage results in cardiac contractions
with greater force, as further calcium is released from cardiac
muscle cells. Toxicity also results in multiple kinds of dysrhythmia
and potentially fatal ventricular tachycardia.

3. Squill

Cardiac glycoside scillarin A is obtained from the fleshy scales of the
bulb, family Liliaceae.

The genin of the squill glycosides is a bufadienolide, which is
characterized by:
• They have a 6-membered doubly unsaturated lactone ring at C-17.
• They have at least one double bond in the steroid nucleus.

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