Hypotensive effect in rats of hydrophilic extract fromTerminalia arjuna containing tannin-related compounds

Abstract

The effects of extracts containing tannin-related compounds from Terminalia arjuna, which has been used in the treatment of cardiovascular disorders by Ayurvedic physicians, on the blood pressure and heart rate of rats were examined. An aqueous extract of Terminalia arjuna produced a transient decrease in blood pressure accompanied by a slight decrease in heart rate. The hypotensive effect was observed with a fraction containing tannin-related compounds (F2) separated from the aqueous extract. The hypotensive effect of F2 was not affected by pretreatment of rats with propranolol, but was attenuated by pretreatment with atropine. The effects on blood pressure of acetylcholine, epinephrine, isoproterenol and bilateral carotid occlusion, were not affected by treatment with F2. These results suggest that an aqueous fraction of Terminalia arjuna containing tannin-related compounds has a hypotensive effect in the rat, which may be mediated by cholinergic mechanisms. © 1997 John Wiley & Sons, Ltd.