title: Mechanism of potent antiperoxidative effect of capsaicin.
abstract: The effect of a pungent ingredient of red pepper, capsaicin, on lipid peroxidation of rat liver mitochondria (RLM) induced by ADP/Fe(2+) was studied. Capsaicin inhibited the lipid peroxidation significantly, being more effective than the well-known antioxidant alpha-tocopherol. Capsaicin was also found to scavenge 1,1'-diphenyl-2-picrylhydrazyl (DPPH) radicals both in solution and in membranes, especially the latter. Capsaicin was found to scavenge radicals both at/near the membrane surface and in the interior of the membrane. The phenolic OH-group of capsaicin remained intact after reaction with DPPH radicals, indicating that the hydroxyl group is not associated with the radical scavenging reaction. From the results of quantum chemical calculations of various radical intermediates derived from the model compound N-vanillylacetamide, and the findings that vanillin and 8-methyl-6-noneamide were major reaction products of capsaicin with DPPH radicals, it was concluded that the radical scavenging site of capsaicin is the C7-benzyl carbon.
authors.affiliation: Faculty of Pharmaceutical Sciences, The University of Tokushima, Shomachi-1, Japan. kogure@ph.tokushima-u.ac.jp
authors.forename: Kentaro
authors.initials: K
authors.lastname: Kogure
authors.forename: Satoru
authors.initials: S
authors.lastname: Goto
authors.forename: Miki
authors.initials: M
authors.lastname: Nishimura
authors.forename: Mina
authors.initials: M
authors.lastname: Yasumoto
authors.forename: Kazutoyo
authors.initials: K
authors.lastname: Abe
authors.forename: Chie
authors.initials: C
authors.lastname: Ohiwa
authors.forename: Hironori
authors.initials: H
authors.lastname: Sassa
authors.forename: Takenori
authors.initials: T
authors.lastname: Kusumi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Terada
mesh_terms: D000244:Adenosine Diphosphate / Q000031:analogs & derivatives*; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D001665:Binding Sites; D002211:Capsaicin / Q000737:chemistry / Q000494:pharmacology*; D004578:Electron Spin Resonance Spectroscopy; D016166:Free Radical Scavengers / Q000494:pharmacology*; D005609:Free Radicals / Q000737:chemistry; D015227:Lipid Peroxidation / Q000187:drug effects; D008297:Male; D008930:Mitochondria, Liver / Q000187:drug effects* / Q000378:metabolism; D015394:Molecular Structure; D010101:Oxygen Consumption; D051381:Rats; D017208:Rats, Wistar; D013053:Spectrophotometry
chemical_list: D000975:Antioxidants; D016166:Free Radical Scavengers; D005609:Free Radicals; C029936:adenosine diphosphate-ferric chelate; D000244:Adenosine Diphosphate; D002211:Capsaicin