Bilobalide, a constituent of Ginkgo biloba L., potentiates drug-metabolizing enzyme activities in mice: possible mechanism for anticonvulsant activity against 4-O-methylpyridoxine-induced convulsions.

Anticonvulsant effects of bilobalide, one of the constituents of Ginkgo biloba L., on the convulsions induced by 4-O-methylpyridoxine (MPN) were investigated in mice. Bilobalide reduced the duration and incidence of MPN-induced convulsions depending on its dose and the period of treatment. In addition, the anticonvulsant effect was manifested more than 24 hours after treatment and the effect lasted for 7 days after its withdrawal. In mice treated with bilobalide (30 mg/kg, p.o., once a day for 4 days), hepatic 7-methoxycoumarin O-demethylase activity was potentiated, and the disappearance of MPN in blood after MPN injection was faster than in controls. From these results, it is assumed that the anticonvulsant effect of bilobalide against convulsions induced by MPN partly involves modulation of hepatic drug-metabolizing enzyme activity, which leads to accelerated elimination of MPN.