title: Comparison of antioxidant abilities of magnolol and honokiol to scavenge radicals and to protect DNA.
abstract: The antioxidant properties of magnolol and honokiol were evaluated in the experimental systems of reducing ONOO(-) and (1)O(2), bleaching β-carotene in linoleic acid (LH) emulsion, and trapping 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) cationic radical (ABTS(+)*) and 2,2'-diphenyl-1-picrylhydrazyl radical (DPPH), and then were applied to inhibit the oxidation of DNA induced by Cu(2+)/glutathione (GSH) and 2,2'-azobis(2-amidinopropane hydrochloride) (AAPH). Magnolol and honokiol were active to reduce ONOO(-) and (1)O(2). Honokiol showed a little higher activity to protect LH and to inhibit Cu(2+)/GSH-induced oxidation of DNA than magnolol. In addition, honokiol exhibited higher activities to trap ABTS(+)* and DPPH than magnolol. In particular, honokiol trapped 2.5 radicals while magnolol only trapped 1.8 radicals in protecting DNA against AAPH-induced oxidation. The obtained results suggested that low antioxidant ability of magnolol may be related to the intramolecular hydrogen bond formed between di-ortho-hydroxyl groups, which hindered the hydrogen atom in hydroxyl group to be abstracted by radicals. Therefore, the antioxidant capacity of magnolol was lower than that of honokiol.
authors.affiliation: Department of Organic Chemistry, College of Chemistry, Jilin University, Changchun 130021, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Zhao
authors.forename: Zai-Qun
authors.initials: ZQ
authors.lastname: Liu
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D001713:Biphenyl Compounds / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D016166:Free Radical Scavengers / Q000737:chemistry*; D017705:Lignans / Q000737:chemistry*; D000498:Allyl Compounds; D010636:Phenols
chemical_list: D000975:Antioxidants; D001713:Biphenyl Compounds; D004247:DNA; D016166:Free Radical Scavengers; D017705:Lignans; C005498:magnolol; C005499:honokiol; D000498:Allyl Compounds; D010636:Phenols