Cardiovascular effects of a withanolide from Withania coagulans, dunal fruits

A new withanolide, with a unique chemical structure similar to the aglycones of the cardiac glycosides, with mol. wt. 488 6, m. p. 260-261 degrees, isolated from the fruits of Withania coagulans, was screened for cardiovascular effects. At doses of 5 mg/kg body weight, the withanolide produced a moderate fall of blood pressure in dogs (34 +/- 2.1, mm Hg) which was blocked by atropine and not by mepyramine or propranolol. In rabbit Langendorff preparation and ECG studies, it produced myocardial depressant effects but in perfused frog heart it produced mild positive inotropic and chronotropic effects.