title: Inhibition of xanthine oxidase by some Chinese medicinal plants used to treat gout.
abstract: The enzyme xanthine oxidase catalyses the oxidation of hypoxanthine to xanthine and then to uric acid, which plays a crucial role in gout. A total of 122 traditional Chinese medicinal plants, selected according to the clinical efficacy and prescription frequency for the treatment of gout and other hyperuricemia-related disorders, have been evaluated for the enzyme inhibitory activity. Among the 122 methanol extracts derived from these species, 69 were shown to be inhibitory at 100 microg/ml, with 29 having greater than 50% inhibition. As to the equal amount of water extracts, 40 were disclosed to be active at 100 microg/ml, with 13 possessing more than 50% inhibition. At 50 microg/ml, 58 methanol and 24 water extracts exhibited inhibitory activity, with 15 of the former and two of the latter showing greater than 50% inhibition. The most active was the methanol extract of the twig of Cinnamomum cassia (Lauraceae) (IC(50), 18 microg/ml), which was followed immediately by those of the flower of Chrysanthemum indicum (Asteraceae) (IC(50), 22 microg/ml) and the leaves of Lycopus europaeus (Lamiatae) (IC(50), 26 microg/ml). Among the water extracts, the strongest inhibition of the enzyme was observed with that of the rhizome of Polygonum cuspidatum (Polygonaceae) (IC(50), 38 microg/ml). The IC(50) value of allopurinol used as a positive control was 1.06 microg/ml. The study demonstrated that the effects for these medicinal plants used for the gout treatment were based, at least in part, on the xanthine oxidase inhibitory action.
authors.affiliation: Institute of Functional Biomolecule, State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, 210093, Nanjing, People's Republic of China.
authors.forename: L D
authors.initials: LD
authors.lastname: Kong
authors.forename: Y
authors.initials: Y
authors.lastname: Cai
authors.forename: W W
authors.initials: WW
authors.lastname: Huang
authors.forename: C H
authors.initials: CH
authors.lastname: Cheng
authors.forename: R X
authors.initials: RX
authors.lastname: Tan
mesh_terms: D004791:Enzyme Inhibitors / Q000302:isolation & purification / Q000627:therapeutic use*; D019448:Ethnobotany; D006073:Gout / Q000188:drug therapy*; D006801:Humans; D008516:Medicine, Chinese Traditional; D010936:Plant Extracts / Q000302:isolation & purification / Q000627:therapeutic use*; D010946:Plants, Medicinal / Q000737:chemistry / Q000201:enzymology*; D014969:Xanthine Oxidase / Q000037:antagonists & inhibitors*
chemical_list: D004791:Enzyme Inhibitors; D010936:Plant Extracts; D014969:Xanthine Oxidase