Effects of Short-term Ginkgo Biloba Extract Feeding on Hypotensive Action of Nicardipine in Rats

摘要

The effects of a Ginkgo biloba extract (GBE)-containing diet for either1,3 or 5 days on the antihypertensive action by the oral treatment of nicardipine were examined in in vitro (cytochrome P450 (CYP) 3 A activities in liver microsome) and in vivo (blood pressure by the tail-cuff method) experiments using Wistar rats. In in vivo experiment, one-day treatment of 0.5% GBE diet significantly strengthened the hypotensive effect of nicardipine. However, both 3- and 5-day treatments of 0.5% GBE diet did not show any significant changes in the hypotensive effect of nicardipine. In in vitro experiment, the simultaneous addition of GBE to liver microsomes of non-treatment rat inhibited the metabolism of nicardipine, in a concentration-dependent manner. These results suggest that GBE strengthened the therapeutic potency of nicardipine, at least in a one-shot treatment, probably due to the acute decreased hepatic drug metabolism.