EGb 761 protects liver mitochondria against injury induced by in vitro anoxia/reoxygenation

The present study investigated the protective effects of Ginkgo biloba extr act (EGb 761) on rat liver mitochondrial damage induced by in vitro anoxia/ reoxygenation. Anoxia/reoxygenation was known to impair respiratory activit ies and mitochondrial oxidative phosphorylation efficiency. ADP/O (2.57 +/- 0.11) decreased after anoxia/reoxygenation (1.75 +/- 0.09, p < .01), as we ll as state 3 and uncoupled respiration (-20%, p < .01), but state 4 respir ation increased (p < .01). EGb 761 (50-200 mu g/ml) had no effect on mitoch ondrial functions before anoxia, but had a specific dose-dependent protecti ve effect after anoxia/reoxygenation. When mitochondria were incubated with 200 mu g/ml EGb 761, they showed an increase in ADP/O (2.09 +/- 0.14, p < .05) and a decrease in state 4 respiration (-22%) after anoxia/reoxygenatio n. In EPR spin-trapping measurement, EGb 761 decreased the EPR signal of su peroxide anion produced during reoxygenation. In conclusion, EGb 761 specia lly protects mitochondrial ATP synthesis against anoxia/reoxygenation injur y by scavenging the superoxide anion generated by mitochondria. (C) 1999 El sevier Science Inc.