Antioxidant and hepatoprotective effects of ginkgo biloba leave extracts

Abstract

The present study was undertaken to investigate the in vitro and the in vivo antioxidant and hepatoprotective effects of Ginkgo biloba leave extracts. Qualitative analysis of different leaves extracts [ethanol 70% (Et), ethyl acetate (EA), and water (W)] revealed the presence of flavonoids, phenolic compounds, saponins, tannins, terpenes, and carbohydrates. The quantitative analysis of the leaves extracts revealed that the Et extract contains the highest amounts of tannins, saponins, flavonoids and phenolic compounds. The EA extract contains higher amounts of flavonoids and phenolic compounds and lower amounts of tannins and saponins compared to the W extract. The in vitro studies revealed that all the Ginkgo biloba leave extracts have a high antioxidant activity. The Et extract showed the highest activity followed by the EA extract then the W extract. Moreover, the in vivo studies revealed that all the Ginkgo biloba leave extracts have hepatoprotective activity, which evidenced by the effect of these extracts on the antioxidant enzymes activities [superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), glutathione-S-transferase (GST)], the liver marker enzymes [alkaline phosphatase (ALP), aspartate transaminase (AST) and alanine transaminase (ALT)], the lipid peroxidation as well as inhibitory effects on nitric oxide (NO) release. The administration of these extracts significantly restored the elevated activities of the liver marker enzymes, and the antioxidant enzymes, which increase during hepatotoxicity. Also, they inhibit the release of NO. The treatment with the Et extract gave the best results for hepatoprotective effects. Moreover, the administration with this extract did not significantly affect the normal values of blood glucose (BG), total proteins (T.P), total lipids (T.L), total cholesterol (T.C), low and high density lipoprotein cholesterol (LDL-c and HDL-c). From this study it can conclude that the treatment with Ginkgo biloba leave extracts can inhibit the hepatotoxicity without toxic effect.