title: Preparation and antioxidant activity of alpha-pyridoin and its derivatives.
abstract: Focusing on alpha-pyridoin (1, 1,2-di(2-pyridyl)-1,2-ethenediol) as the lead compound of the novel antioxidative enediol, we synthesized 5,5'- or 6,6'-bis-substituted derivatives of 1 from disubstituted pyridines. The antioxidant activity of 1 and its synthetic derivatives 2-7 was evaluated by DPPH (1,1-diphenyl-2-picrylhydrazyl radical) scavenging assay and inhibition of lipid peroxidation. In the DPPH assay, 1 exhibited an activity stronger than that of ascorbic acid, and 5,5'-dimethyl-(5) or 5,5'-dimethoxy-substituted derivatives (6) exhibited more potent activity than 1. The DPPH scavenging activities of alpha-pyridoins were correlated with their oxidation potential and thus the electron density of enediol. 5 and 6 effectively inhibited lipid peroxidation in the rat liver microsome/tert-butyl hydroperoxide system. Therefore, 5 and 6 serve as good candidates for a pharmacologically useful enediol antioxidant.
authors.affiliation: Kyoritsu University of Pharmacy, Shibakoen 1-5-30, Minato-ku, Tokyo 105-8512, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Hatanaka
authors.forename: Kyoko
authors.initials: K
authors.lastname: Takahashi
authors.forename: Shigeo
authors.initials: S
authors.lastname: Nakamura
authors.forename: Tadahiko
authors.initials: T
authors.lastname: Mashino
mesh_terms: D000447:Aldehydes / Q000737:chemistry; D000818:Animals; D000975:Antioxidants / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D001573:Benzoin / Q000737:chemistry; D001713:Biphenyl Compounds / Q000737:chemistry; D006834:Hydrazines / Q000737:chemistry; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010851:Picrates; D011728:Pyridones / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D051381:Rats
chemical_list: D000447:Aldehydes; D000975:Antioxidants; D001713:Biphenyl Compounds; D006834:Hydrazines; D010851:Picrates; D011728:Pyridones; C004931:1,1-diphenyl-2-picrylhydrazyl; D001573:Benzoin