title: Xanthine oxidase inhibitors from the heartwood of Vietnamese Caesalpinia sappan.
abstract: From the MeOH extract of Vietnamese Caesalpinia sappan, a novel biogenetically exclusive benzindenopyran, with a new carbon framework, neoprotosappanin (1), and a new compound, protosappanin A dimethyl acetal (3), were isolated together with protosappanin E-2 (2), neosappanone A (4), and 13 previously reported phenolic compounds (5-17). Their structures were elucidated on the basis of spectroscopic data. Compounds 1-4, 7, 13, and 15-17 showed significant xanthine oxidase inhibitory activity in a concentration-dependent manner, and sappanchalcone (17) showed the most potent activity with an IC50 value of 3.9 microM, comparable to that of positive control allopurinol (IC50, 2.5 microM). The kinetic study of these inhibitors indicated that they are competitive inhibitors, the same as allopurinol, except for 1 and 16 which are noncompetitive inhibitors.
authors.affiliation: Institute of Natural Medicine, Toyama Medical and Pharmaceutical University, 2630 Sugitani, Toyama 930-0194, Japan.
authors.forename: Mai Thanh Thi
authors.initials: MT
authors.lastname: Nguyen
authors.forename: Suresh
authors.initials: S
authors.lastname: Awale
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Tezuka
authors.forename: Quan Le
authors.initials: QL
authors.lastname: Tran
authors.forename: Shigetoshi
authors.initials: S
authors.lastname: Kadota
mesh_terms: D001578:Benzopyrans / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D029911:Caesalpinia / Q000737:chemistry*; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D009682:Magnetic Resonance Spectroscopy; D010636:Phenols / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D016339:Spectrometry, Mass, Fast Atom Bombardment; D013055:Spectrophotometry, Infrared; D014969:Xanthine Oxidase / Q000037:antagonists & inhibitors*
chemical_list: D001578:Benzopyrans; D004791:Enzyme Inhibitors; D010636:Phenols; C504498:neoprotosappanin; C090723:protosappanin A; D014969:Xanthine Oxidase