Preparative Isolation and Antitumor Activity of Six Ginkgol Monomersfrom Ginkgo biloba

Abstract

Ginkgols are bioactive compounds from Ginkgo biloba L., exhibiting excellent antitumor activity. For research on the structure-activity relationships, four ginkgol monomers (C13:0, C15:1-Δ8, C17:2-Δ9, 12, C15:0) and two ginkgol isomers (C17:1-Δ10, C17:1-Δ12) were isolated successively by preparative HPLC and identified. The results of MTT assay showed that all of the ginkgol monomers exhibited cytotoxicity against HepG2 and HGC cells. Ginkgol monomers with unsaturated side chains performed stronger inhibitory effects than which with saturated side chains. The IC50 values of ginkgol C15:1-Δ8, C17:2-Δ9, 12, C17:1-Δ10, C17:1-Δ12 on HepG2 and HGC cells were in sequence: 5.69 and 3.94, 19.95 and 11.09, 19.79 and 10.22, 22.76 and 11.4 μg/mL. Among which, ginkgol C15:1-Δ8 showed the strongest cytotoxicity with the lowest IC50 values. As for the two ginkgol C17:1 isomers, double bond at Δ10 performed higher antitumor activities than that at Δ12. The IC50 values of ginkgol C17:2 with two double bonds were close to that of ginkgol C17:1 with one double bond.