Effects of Gingko Extract (EGb761) on oxidative damage under different conditions of serum supply

Standardized Ginkgo biloba extract EGb761 is known to have multivalent properties such as anti-oxidation and anti-apoptosis. In this study, we determined in rat pheochromocytoma (PC12) cells effects of EGb761 treatment on oxidative damage under three different conditions of serum supply: normal growth medium (NGM), serum deprivation (SE) and serum deprivation followed by re-supply (SERS). It was found that, under the condition of serum deprivation, oxidative damage induced less cell death than the condition of serum supply. This appears to be related to inhibition of mitochondrial metabolism. Moreover, after serum deprivation, serum re-supply exacerbated cell necrosis, possibly through enhancement of oxidative damage. EGb761 could attenuate oxidative damage under the condition of serum supply whereas no protective effect on serum-depleted cells was observed. These results suggest that, there is a synergistic effect between trophic factors and EGb761. EGb761 treatment may protect cells from possible oxidative damage induced by the trophic factors. On the other hand, trophic factors appear to strengthen the protective effect of EGb761. To fully understand the synergistic interaction between antioxidants and trophic factors will help to sort out rational use of drugs in clinic practice.