Inhibitory effect of verbascoside on xanthine oxidase activity.

In this study, we analyzed the inhibitory effect of verbascoside against xanthine oxidase (XOD) in vitro by using animal model and in vivo by direct inhibition assay. Results showed that verbascoside could reduce uric acid in rat serum and inhibit XOD activity in rat liver. The IC50 value of restraining XOD activity was 81.11mgmL-1. Fluorescence chromatographic analysis and circular dichroism spectroscopy indicated that the secondary structures of XOD were changed after incubation with verbascoside. The docking simulation showed that verbascoside could enter into the active site of XOD and form hydrogen bonding with amino acid residues (such as Lys-1045, Arg-880, Arg-912, Glu-1261 and Gln-1194). The results suggested that verbascoside, which is a naturally occurring water-soluble antioxidant, could be a potential low-toxicity XOD inhibitor for hyperuricemia treatment.