Mechanism of potent antiperoxidative effect of capsaicin.
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.
Kogure
Kentaro
K
Faculty of Pharmaceutical Sciences, The University of Tokushima, Shomachi-1, Japan. kogure@ph.tokushima-u.ac.jp
Goto
Satoru
S
Nishimura
Miki
M
Yasumoto
Mina
M
Abe
Kazutoyo
K
Ohiwa
Chie
C
Sassa
Hironori
H
Kusumi
Takenori
T
Terada
Hiroshi
H
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
D000975:Antioxidants; D016166:Free Radical Scavengers; D005609:Free Radicals; C029936:adenosine diphosphate-ferric chelate; D000244:Adenosine Diphosphate; D002211:Capsaicin