HYPOTENSIVE EFFECT IN RATS OF HYDROPHILIC EXTRACT FROM TERMINALIA-ARJUNA CONTAINING TANNIN-RELATED COMPOUNDS

The effects of extracts containing tannin-related compounds from Termi nalia arjuna, which has been used in the treatment of cardiovascular d isorders by Ayurvedic physicians, on the blood pressure and heart rate of rats were examined, An aqueous extract of Terminalia arjuna produc ed a transient decrease in blood pressure accompanied by a slight decr ease in heart rate, The hypotensive effect was observed with a fractio n 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 atr opine. The effects on blood pressure of acetylcholine, epinephrine, is oproterenol and bilateral carotid occlusion, were not affected by trea tment with F2, These results suggest that an aqueous fraction of Termi nalia arjuna containing tannin-related compounds has a hypotensive eff ect in the rat, which may be mediated by cholinergic mechanisms. (C) 1 997 by John Wiley & Sons, Ltd.