Abstract: To study the inhibitory activities of ginkgolic acid monomers from Ginkgo biloba sarcotesta on xanthine oxidase (XOD) in vitro for the first time,the absolute ethanol extract of Ginkgo biloba sarcotesta was separated by open silica gel column chromatography and purified by semi-preparative reversed phase HPLC subsequently,and five ginkgolic acid monomers were obtained.Their inhibitory activities on XOD in vitro were evaluated by microplate-based method,and allopurinol was used as a positive drug.Each concentration had four replicates,and mean inhibition ratios were calculated according to absorbance measured on a microplate reader at 295 nm.The experiments were repeated for three times,and the half inhibitory concentration (IC₅₀) was calculated by using Graphpad prism 5.0 software.Conclusion was made that ginkgolic acid (13∶0) and ginkgolic acid (15∶1) have shown certain inhibitory activities on XOD in vitro,and their IC₅₀ values were 31.81±1.87 μmol/L and 25.48±0.66 μmol/L (n=3),respectively.

Key words: Ginkgo biloba sarcotesta, ginkgolic acid monomers, xanthine oxidase, inhibitory activity