title: Antioxidant activity of the new thiosulfinate derivative, S-benzyl phenylmethanethiosulfinate, from Petiveria alliacea L.
abstract: The antioxidant effects of the new thiosulfinate derivative, S-benzyl phenylmethanethiosulfinate (BPT), against the oxidation of cumene and methyl linoleate (ML) in chlorobenzene were studied in detail using HPLC. The results showed that BPT provided effective inhibition with a well-defined induction period under these oxidation conditions, and it was found that the stoichiometric factor (n), the number of peroxyl radicals trapped by one antioxidant molecule, of BPT is about 2. We then undertook a thorough investigation aimed at elucidating the active structural site of BPT. Various model compounds, such as diphenyl disulfide, dibenzyl disulfide, S-phenyl benzenethiosulfinate and S-ethyl phenylmethanethiosulfinate, were used which provided evidence that the benzylic hydrogen of BPT is mainly associated with the peroxyl radical scavenging. Moreover, we measured the rate constant for the reaction of BPT with peroxyl radicals derived from cumene and ML in chlorobenzene, and based on these measurements, BPT reacts with these peroxyl radicals with a rate constant of k(inh) = 8.6 x 10(3) and 6.2 x 10(4) M(-1) s(-1), respectively.
authors.affiliation: Department of Analytical Chemistry, Faculty of Health Sciences, Kyorin University, 476 Miyasita-cho, Hachioji, Tokyo 192-8508, Japan.
authors.forename: Youji
authors.initials: Y
authors.lastname: Okada
authors.forename: Kaoru
authors.initials: K
authors.lastname: Tanaka
authors.forename: Eisuke
authors.initials: E
authors.lastname: Sato
authors.forename: Haruo
authors.initials: H
authors.lastname: Okajima
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D001555:Benzene Derivatives / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D016166:Free Radical Scavengers / Q000737:chemistry; D007700:Kinetics; D008041:Linoleic Acids / Q000737:chemistry; D010084:Oxidation-Reduction; D029602:Phytolaccaceae / Q000737:chemistry*; D018517:Plant Roots / Q000737:chemistry; D013329:Structure-Activity Relationship; D013441:Sulfinic Acids / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D001555:Benzene Derivatives; D016166:Free Radical Scavengers; D008041:Linoleic Acids; C529747:S-benzyl phenylmethanethiosulfinate; D013441:Sulfinic Acids; C005575:methyl linoleate; C015763:cumene