Acetylcholinesterase Inhibitory Activities of Flavonoids from the Leaves of Ginkgo biloba against Brown Planthopper

Ginkgo biloba is a traditional Chinese medicinal plant which has potent insecticidal activity against brown planthopper. The MeOH extract was tested in the acetylcholinesterase (AChE) inhibitory assay with IC 50 values of 252.1 μ g/mL. Two ginkgolides and thirteen flavonoids were isolated from the leaves of Ginkgo biloba . Their structures were established on the basis of spectroscopic data interpretation. It revealed that the 13 isolated flavonoids were found to inhibit AChE with IC 50 values ranging from 57.8 to 133.1 μ g/mL in the inhibitory assay. AChE was inhibited dose dependently by all tested flavonoids, and compound 6 displayed the highest inhibitory effect against AChE with IC 50 values of 57.8 μ g/mL.