Prunes could exert cardiovascular protective effects. Trials have demonstrated antihypertensive
effects of Prunus domestica. The aim of this study was to find out if prunes could
alter cardiac functions that may help understanding the mode of control of hypertension.
Changes in rate and contractile force of frogs' heart were recorded using Power Lab.
Effects of prunes' extracts: aqueous (10, 20, 40%); methanolic, acetonic, ethanolic
and chloformic (10%); were evaluated and compared with other drugs. We tested effects
of acetylcholine and atropine (10(-5)), adrenaline, propranolol, verapamil and diltiazem
(10); NaCl, KCl, CaCl2, MgCl2 (10% w/v) on frog's heart alone and with prunes/drugs.
All extracts of prunes significantly reduced HR and contractile force. Prunes combined
with acetylcholine, propranolol or verapamil significantly enhanced bradycardia; whereas
it blocked tachycardia produced by epinephrine, atropine or calcium; moreover prunes
blocked the significant increase in HR and cardiac contractility produced by CaCl2;
and reduced HR along with MgCl2. NaCl and KCl alone or with prunes had non-significant
effects on frog's heart. In conclusion, Prunus domestica plays a key role in modification
of intracellular Ca+2 concentration resulting in negative ionotropic and chronotropic
effects (similar to cholinergic stimulation and adrenergic or calcium channel blockade)
that could lead to hypotensive effects.