Cardiovascular pharmacology of Panax notoginseng (Burk) F.H. Chen and Salvia miltiorrhiza.

The cardiovascular pharmacology of two Chinese herbs, Salvia miltiorrhiza (SM) and Panax notoginseng (Burk) F. H. Chen (PNG) were studied both in vivo and in vitro. Extracts of both herbs suppressed systemic blood pressure in albino rats and rabbits, an effect which was blocked or reversed by atropine, propranolol, and chlorpheniramine plus cimetidine. This reversed hypertension was blocked by phenoxybenzamine. These results indicate that these herbs have multiple effector sites in the cardiovascular system. This could be due to an increased utilization of extracellular calcium ions since the activity of SM on isolated blood vessels of rabbits was enhanced by 2 mM Ca++. The effects of aqueous extract of SM and purified active principles of SM (tanshinones) on rat and rabbit blood vessels in vitro were very similar both qualitatively and quantitatively. Both caused vasodilation of coronary arteries at all concentrations tested but induced vasodilation of renal, mesenteric and femoral arteries only at low concentrations. At higher concentrations, vasoconstriction was induced in these vessels. These results indicate that an economical decoction of SM is as efficacious as the more expensive isolated tanshinones. Both SM and PNG would be useful as antianginal agents since they dilate coronary vessels. Their use in hypertension is questionable since they induce both vasodilation and vasoconstriction depending on dose and target vessel.