Different effects of the constituents of EGb761 on apoptosis in rat cerebellar granule cells induced by hydroxyl radicals

The present study was conducted to evaluate the different effects of the co nstituents of EGb761(Ginkgo biloba Extract) on apoptosis in cerebellar gran ule cells induced by hydroxyl radicals. The total flavonoid component of EG b761, two pure EGb761 components (rutin and quercetin), and a mixture of fl avonoids and terpenes protected cerebellar granule cells from oxidative dam age and apoptosis induced by hydroxyl radicals. ESR(electron spin resonance ) results showed that the IC,, of the flavonoids for scavenging hydroxyl ra dicals was almost the same as that of EGb761, even though flavonoids make u p only 24% of EGb761, implying that other constituents of EGb761 besides fl avonoids can scavenge hydroxyl radicals. Total terpenes of EGb761 did not p rotect against apoptosis. Flavonoids and terpenes did not show a synergisti c effect in this regard. Terpenes did not scavenge hydroxyl radicals direct ly, which might be related to their "cage-like" structures.