title: An apigenin-derived xanthine oxidase inhibitor from Palhinhaea cernua.
abstract: Fractionation of the ethanol extract of Palhinhaea cernua afforded a new (1) and two known p-coumaroylated apigenin glycosides (2, 3) in addition to dillenetin, rhamnazin, alpha-onocerin, beta-sitosterol, and (E)-2-hydroxy-5-methoxycinnamic acid. The structure of compound 1 was elucidated as apigenin-4'-O-(2' '-O-p-coumaroyl)-beta-D-glucopyranoside by a combination of its spectroscopic data. The new glycoside 1 inhibits xanthine oxidase (IC(50): 23.95 +/- 0.43 microM) in a competitive-noncompetitive manner with K(i) and K(I) values of 14.35 and 93.68 microM, whereas compounds 2 and 3 were inactive. The distribution and significance of acylated flavonoid glycosides are discussed.
authors.affiliation: Institute of Functional Biomolecules, State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, People's Republic of China.
authors.forename: Rui H
authors.initials: RH
authors.lastname: Jiao
authors.forename: Hui M
authors.initials: HM
authors.lastname: Ge
authors.forename: Da H
authors.initials: da H
authors.lastname: Shi
authors.forename: Ren X
authors.initials: RX
authors.lastname: Tan
mesh_terms: D047310:Apigenin / Q000737:chemistry / Q000302:isolation & purification / Q000493:pharmacokinetics; D002681:China; D005960:Glucosides / Q000737:chemistry / Q000302:isolation & purification / Q000493:pharmacokinetics; D029542:Lycopodiaceae / Q000737:chemistry*; D015394:Molecular Structure; D010946:Plants, Medicinal / Q000737:chemistry*; D014969:Xanthine Oxidase / Q000037:antagonists & inhibitors*
chemical_list: D005960:Glucosides; C513466:apigenin-4'-O-(2' '-O-p-coumaroyl)-beta-D-glucopyranoside; D047310:Apigenin; D014969:Xanthine Oxidase