AIM To rapidly screen xanthine oxidase(XOD)inhibitors from Smilax glabra Roxb.by enzyme-immobilized magnetic microspheres and LC-MS/MS,and to confirm the anti-uric acid constituents from S.glabra Roxb.METHODS The immobilized xanthine oxidase was prepared by covalent coupling with carboxyl magnetic beads as a carrier.The xanthine oxidase inhibitors in S.glabra were screened by the specific adsorption of immobilized enzyme.LC-MS/MS and standard substances were used for analysis and comparison,and the inhibitory activity and inhibition type of the screened and identified components were investigated.RESULTS The successful synthesis of immobilized xanthine oxidase was characterized by scanning electron microscopy and infrared spectroscopy.The enzyme loading was 70.50 μg/mg and the relative activity was 79.44%.Thirteen active compounds were screened from the extract of S.glabra,and eleven compounds were identified.The enzyme activity test showed that the inhibitory activites of engeletin and isoengeletin were the strongest,which was close to the positive control allopurinol.The IC50 value and inhibition type were 32.25 μg/mL,mixed inhibition,35.12 μg/mL,competitive inhibition.CONCLUSION The method is simple,rapid,accurate and suitable for directly screened active ingredients which can inhibit XOD from complex extract of traditional Chinese medicines.
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