The Ginkgo biloba extract EGb761 reduces stress sensitivity, ROS accumulation and expression of catalase and glutathione S-transferase 4 in Caenorhabditis elegans.

The standardised extract EGb761 from the leaves of Ginkgo biloba is a popular herbal dietary supplement and it is used as a phytopharmacon for the therapy of diverse cerebral insufficiencies. The beneficial impact of EGb761 is believed to be conferred by diverse biological actions under physiological conditions as well as in response to stress. In this study we examined effects of EGb761 in the model organism Caenorhabditis elegans. EGb761 reduced the body size but did not affect the reproduction of C. elegans. In fluorescence-based assays performed in microtiter plates we demonstrated the protective action of EGb761 by the increase of resistance to thermal stress and the attenuation of ROS accumulation under conditions of thermal stress in single living worms. Under normal conditions the lifespan of the worms was extended by the EGb761 supporting the beneficial effects found under stress conditions. In a reporter gene approach using individual living worms the expression of the stress-inducible glutathione S-transferase 4 was shown to be reduced by EGb761 under physiological conditions as well as under oxidative stress. EGb761 also led to a decrease in transcription of the stress-inducible catalase genes. These results suggest that the beneficial impact of EGb791 on resistance to thermal stress and lifespan in C. elegans is at least partially due to its ability to relieve oxidative stress.