Page 88 - Pharmd general phytochemistry I-Final2024_LEUCTERS

Quantitative determination
• Colorimetric methods based on color tests e.g. using Baljet's or

Kedde's reagents

Structure-Activity Relationship (S.A.R)

I- Sugar moiety
• The sugar moieties have no cardiac activities, but when attached

to the 3-OH group of the steroid, they are of great influence on
the solubility, absorption and the pharmacokinetic behavior.
• The free aglycones are less potent than any of their
glycosides.
II- Aglycone moiety
• Opening of the lactone ring by alkali, results in loss of the
activity.
• Saturation of the lactone ring reduces the potency 10 folds or
even destroy the cardiac activity.
• The cis junction of the ring A/B and C/D is required for the
cardiac activity

Indications and uses
Cardiac glycosides are of great therapeutic value In the treatment of
• Congestive heart failure (elderly people).

- They improve myocardial contractility,
- Increase cardiac output,
- promote diuresis,
- Reduce edema,
- Reduce pulmonary vascular congestion

• Used for treatment of atrial tachyarrhythmia (atrial
fibrillation).

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