Profile of the main bioactive compounds and in vitro biological activity of different solvent extracts from Ginkgo biloba exocarp

In order to make good use of Ginkgo biloba exocarps as agricultural residues, the present work was conducted aiming to evaluate the main bioactive compounds and in vitro biological activities of different solvent (petroleum ether, ethyl acetate, n-hexane, acetone, ethanol, and methanol) Ginkgo biloba exocarp extracts. The methanol extracts with the highest content of total phenolics and total flavonoids showed the strongest antioxidant and antibacterial activities. n-Hexane extracts had the lowest total phenolics, flavonoids and antioxidant activities, however, it exhibited moderately high antibacterial activities compared to other extracts. More interestingly, the n-hexane extracts with the highest ginkgolic acid content had the strongest inhibitory ability on HepG2 cell viability, and then ethyl acetate, petroleum ether, acetone, ethanol, and methanol extracts. The results showed that bioactive compounds and biological activities of extracts from Ginkgo biloba exocarp were greatly affected by the extraction solvents. Therefore, the selective extraction from Ginkgo biloba exocarp is very important for processing and comprehensive utilization of Ginkgo biloba exocarp.