The Hypouricemic Effect ofBalanophora laxifloraExtracts and Derived Phytochemicals in Hyperuricemic Mice

Abstract

The objective of this study is to evaluate the lowering of uric acid usingBalanophora laxifloraextracts and derived phytochemicals on potassium-oxonate-(PO-) induced hyperuricemia in mice. The results revealed that ethyl acetate (EtOAc) fraction ofB. laxifloraextracts exhibited strong xanthine-oxidase-(XOD-) inhibitory activity. In addition, among the 10 subfractions (EA1–10) derived from EtOAc fraction, subfraction 8 (EA8) exhibited the best XOD-inhibitory activity. Four specific phytochemicals, 1-O-(E)-caffeoyl-β-D-glucopyranose (1), 1-O-(E)-p-coumaroyl-β-D-glucopyranose (2), 1,3-di-O-galloyl-4,6-(S)-hexahydroxydiphenoyl-β-D-glucopyranose (3), and 1-O-(E)-caffeoyl-4,6-(S)-hexahydroxydiphenoyl-β-D-glucopyranose (4), were further isolated and identified from this subfraction. Compounds3and4exhibited the strongest XOD-inhibitory activity compared with other compounds, and both hydrolyzable tannins were determined to be noncompetitive inhibitors according to the Lineweaver-Burk plot. On the other hand, thein vivohypouricemic effect in hyperuricemic mice was consistent with XOD-inhibitory activity, indicating thatB. laxifloraextracts and derived phytochemicals could be potential candidates as new hypouricemic agents.