title: Lonicera hypoglauca inhibits xanthine oxidase and reduces serum uric acid in mice.
abstract: Xanthine oxidase (XOD) catalyzes the oxidation of hypoxanthine to xanthine and then to uric acid, and is a key enzyme in the pathogenesis of hyperuricemia. The ability of extracts of Lonicera hypoglauca (Caprifoliaceae) to inhibit XOD was investigated in this study. An ethanol extract (LH-crude) of the leaves of L. hypoglauca and its derived EtOAc soluble sub-fractions (LH-EA) significantly inhibited XOD activity, with IC50 values for LH-crude and LH-EA of 48.8 and 35.2 microg/mL. Moreover, LH-EA reduced serum urate levels IN VIVO in a potassium oxonate-induced hyperuricemic mouse model, by 70.1% and 93.7% of the hyperuricemic untreated group at doses of 300 and 500 mg/kg of LH-EA, respectively. Finally, we used bioactivity-guided fractionation to isolate a new bisflavonoid, loniceraflavone, which showed significant inhibition of XOD (IC50=0.85 microg/mL). These results suggest that L. hypoglauca and its extracts may have a considerable potential for development as an anti-hyperuricemia agent for clinical application.
authors.affiliation: School of Chinese Medicine Resources, China Medical University, Taichung, Taiwan.
authors.forename: Shih-Chang
authors.initials: SC
authors.lastname: Chien
authors.forename: Chen-Wei
authors.initials: CW
authors.lastname: Yang
authors.forename: Yen-Hsueh
authors.initials: YH
authors.lastname: Tseng
authors.forename: Hsin-Sheng
authors.initials: HS
authors.lastname: Tsay
authors.forename: Yueh-Hsiung
authors.initials: YH
authors.lastname: Kuo
authors.forename: Sheng-Yang
authors.initials: SY
authors.lastname: Wang
mesh_terms: D000818:Animals; D005419:Flavonoids / Q000737:chemistry / Q000494:pharmacology; D033461:Hyperuricemia / Q000097:blood / Q000139:chemically induced* / Q000188:drug therapy; D031239:Lonicera / Q000737:chemistry*; D008297:Male; D008516:Medicine, Chinese Traditional; D051379:Mice; D008813:Mice, Inbred ICR; D015394:Molecular Structure; D010936:Plant Extracts / Q000737:chemistry* / Q000494:pharmacology*; D014527:Uric Acid / Q000097:blood*; D014969:Xanthine Oxidase / Q000037:antagonists & inhibitors*
chemical_list: D005419:Flavonoids; D010936:Plant Extracts; C540621:loniceraflavone; D014527:Uric Acid; D014969:Xanthine Oxidase