title: Antioxidant activity from the stem bark of Albizzia julibrissin.
abstract: The antioxidant activity of the stem bark from Albizzia julibrissin was evaluated for its potential to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, to inhibit the generation of the hydroxyl radical (*OH), total reactive oxygen species (ROS) and to scavenge authentic peroxynitrites (ONOO-). The methanol extract of A. julibrissin exhibited strong antioxidant activity in the tested model systems. Therefore, it was further fractionated using several solvents. The antioxidant activity of the individual fractions were in the order of ethyl acetate (EtOAc) > n-butanol (n-BuOH) > dichloromethane (CH2Cl2) > and water (H2O). The ethyl acetate soluble fraction, which exhibited strong antioxidant activity, was further purified by repeated silicagel, Sephadex LH-20 and RP-18 gel column chromatography. Sulfuretin (1) and 3',4',7-trihydroxyflavone (2) were isolated as the active principles. Compounds 1 and 2 exhibited good activity in all tested model systems. Compound 1 exhibited five times more inhibitory activity on the total ROS than Trolox. Compound 2 showed six times stronger DPPH radical scavenging activity than L-ascorbic acid. These results show the possible antioxidant activity of the A. julibrissin crude extract and its major constituents.
authors.affiliation: Faculty of Food Science and Biotechnology, Pukyong National University, Busan 608-737, Korea.
authors.forename: Mee Jung
authors.initials: MJ
authors.lastname: Jung
authors.forename: Hae Young
authors.initials: HY
authors.lastname: Chung
authors.forename: Sam Sik
authors.initials: SS
authors.lastname: Kang
authors.forename: Jin Ho
authors.initials: JH
authors.lastname: Choi
authors.forename: Kae Sun
authors.initials: KS
authors.lastname: Bae
authors.forename: Jae Sue
authors.initials: JS
authors.lastname: Choi
mesh_terms: D031289:Albizzia; D000818:Animals; D000975:Antioxidants / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D016166:Free Radical Scavengers / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D007668:Kidney / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D024301:Plant Bark; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D018547:Plant Stems; D051381:Rats; D017208:Rats, Wistar
chemical_list: D000975:Antioxidants; D016166:Free Radical Scavengers; D010936:Plant Extracts