Cardiovascular studies of white squill [urginea maritima] extract

ABSTRACT

The White Squill [Urginea maritime] has been used as a medicinal plant through centuries over the world, believed to have certain traditional actions. The Squill bulb was used by herbalists traditionally for the treatment of cardiac failure, chronic bronchitis, rodenticides and asthma. Novel cardiac glycosides recently have been isolated from squill known as bufodienolides. In this study in vivo and in vitro pharmacological properties of extract of white squill were evaluated. Eighteen local domestic rabbits [Oryctolagus cuniculus] were used for in vitro studies [effect of the plant extract on isolated pulmonary arteries and atrium] and in vivo studies [effect of the extract on renal function]. While six male albino rats were used for studying the effects of the plant extract on blood pressure and heart rate. White squill extract induced a quite clear positive inotropic effect. The extract also produced significant increases in urine flow, total solute excretion, urinary Na* excretion rate and significant reduction in urinary K excretion rate in rabbits. White squill extract produced a fall in blood pressure of the rat which was accompanied by a negative chronotropic effect. The positive inotropic effect results mostly likely from blocking Na/ K- ATPase by glycoside constituent of the extract. The diuretic and natriuretic effects of the plant extract look like effects of potassium sparing diuretics. The hypotensive effect could be attributed to its diuretic property. The mechanism of bradycardia might be due to increased vagal tone, a reflex mechanism through baroreceptors