Ethanol extract of Sophora japonica flower bud, an effective potential dietary supplement for the treatment of hyperuricemia

Hyperuricemia (HUA) is a common metabolic condition associated with a variety of diseases, mainly manifested by the increase in uric acid (UA) levels. As xanthine oxidase (XOD) is the key enzyme in UA production, it has become a target for treating HUA. In this study, an extract named EESJ was extracted from Sophora japonica using 80% ethanol solution and administered to HUA mice to verify its UA-lowering effect. The results confirmed that administering EESJ could reduce the UA levels in vivo by inhibiting XOD activity, and ameliorating renal injury in a dose-dependent manner. To further study the active components in EESJ, 243 chemical components and 32 blood components were identified by the UHPLC-Q-TOF-MS/MS technology, of which flavonoids were the main constituents. The molecular docking results showed that the following six compounds, namely hydroxygenkwanin, genistein, tectorigenin, kaempferol, sophoricoside, and quercetin, had strong binding properties with XOD; among which hydroxygenkwanin had the best binding capacity. In conclusion, this study confirmed that EESJ could effectively reduce UA levels, and speculated the active compounds playing a role in lowering UA levels, which has certain guiding significance for Sophora japonica and natural compounds as potentially effective treatment options for HUA.