Extracts of Ginkgo biloba and Panax ginseng protect brain proteins from free radical induced oxidative damage in vitro

Oxidative damage to normal human brain tissue was induced following exposure to hydroxyl (OH.) or superoxide (O-2(-.)) free radical species generated by CO60 irradiation in vitro. Both enzymic and cytoskeletal proteins showed substantial (dose dependent) oxidative damage following exposure to OH. or O-2(-.), as quantified by SDS-polyacrylamide gel electrophoretic analysis. Extracts of Ginkgo biloba or Panax ginseng showed a remarkable capacity to protect brain tissue proteins from oxidative damage in vitro, even at extreme (2000 kRads) dosage levels of OH. or O-2(-.). We suggest, therefore, that the beneficial effect of these plant extracts in preventing brain tissue damage in vivo (e.g. following ischemia-reperfusion) may result from their action in protecting brain proteins from oxidative damage, in addition to their previously reported capacity to reduce free radical induced lipid peroxidation.