title: Antioxidant activity of phytoestrogenic isoflavones.
abstract: The aim of this work was to determine the antioxidant activities of a range of phytoestrogenic isoflavones. The antioxidant activity in the aqueous phase was determined by means of the ABTS.+ total antioxidant activity assay. The results show that the order of reactivity in scavenging the radical in the aqueous phase is genistein > daidzein = genistin approximately equal to biochanin A = daidzin > formononetin approximately equal to ononin, the latter displaying no antioxidant activity. The importance of the single 4'-hydroxyl group in the reactivity of the isoflavones, as scavengers of aqueous phase radicals, as well as the 5'7-dihydroxy structure is demonstrated. Examination of their abilities to enhance the resistance of low density lipoproteins to oxidation supports the observation that genistein is the most potent antioxidant among this family of compound studied, both in the aqueous and in the lipophilic phases.
authors.affiliation: International Antioxidant Research Centre UMDS-Guy's Hospital, London.
authors.forename: M B
authors.initials: MB
authors.lastname: Ruiz-Larrea
authors.forename: A R
authors.initials: AR
authors.lastname: Mohan
authors.forename: G
authors.initials: G
authors.lastname: Paganga
authors.forename: N J
authors.initials: NJ
authors.lastname: Miller
authors.forename: G P
authors.initials: GP
authors.lastname: Bolwell
authors.forename: C A
authors.initials: CA
authors.lastname: Rice-Evans
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D003300:Copper / Q000737:chemistry; D004968:Estrogens, Non-Steroidal / Q000737:chemistry*; D016166:Free Radical Scavengers / Q000737:chemistry; D019833:Genistein; D007529:Isoflavones / Q000737:chemistry*; D008077:Lipoproteins, LDL / Q000737:chemistry; D010084:Oxidation-Reduction; D048789:Phytoestrogens; D028321:Plant Preparations; D010944:Plants / Q000737:chemistry
chemical_list: D000975:Antioxidants; D004968:Estrogens, Non-Steroidal; D016166:Free Radical Scavengers; D007529:Isoflavones; D008077:Lipoproteins, LDL; D048789:Phytoestrogens; D028321:Plant Preparations; C040641:genistin; C004742:daidzein; D003300:Copper; D019833:Genistein; C004541:biochanin A