Protection by bilobalide of the ischaemia-induced alterations of the mitochondrial respiratory activity

Ischaemia is a common feature of most vascular diseases. There is evidence from experimental and clinical studies that Ginkgo biloba extract protects tissues from ischaemia/reperfusion damages. Bilobalide seems to be responsi ble, at least in part, for this activity. However, the mechanism of the pro tection afforded by bilobalide is not yet known. In this work, the effects of bilobalide on mitochondrial respiration were investigated during liver a nd brain ischaemia, since mitochondria alteration is an early event in isch aemia-induced damage. Bilobalide could prevent the decrease in respiratory activity induced by ischaemia in liver and in brain, both when glutamate/ma late or succinate was used as substrate. Ischaemia decreased state 3 respir ation rate and bilobalide prevented this decrease. While bilobalide was not able to prevent the decrease in adenine translocase activity, it protected complex I activity. Bilobalide allows mitochondria to maintain their respi ratory activity in ischaemic conditions by protecting complex I and probabl y complex III activities. Hence, the energetic pool of tissues is preserved during the ischaemic period as well as its viability. This mechanism provi des a possible explanation for the anti-ischaemic properties of bilobalide and of Ginkgo biloba extract in therapeutic interventions. (C) 2000 Edition s scientifiques et medicales Elsevier SAS.