title: Antioxidant mechanism of Mn(II) in phospholipid peroxidation.
abstract: Antioxidant action of Mn2+ on radical-mediated lipid peroxidation without added iron in microsomal lipid liposomes and on iron-supported lipid peroxidation in phospholipid liposomes or in microsomes was investigated. High concentrations of Mn2+ above 50 microM inhibited 2,2'-azobis (2-amidinopropane) (ABAP)-supported lipid peroxidation without added iron at the early stage, while upon prolonged incubation, malondialdehyde production was rather enhanced as compared with the control in the absence of Mn2+. However, in a lipid-soluble radical initiator, 2,2'-azobis (2,4-dimethyl-valeronitrile) (AMVN)-supported lipid peroxidation of methyl linoleate in methanol Mn2+ apparently did not scavenge lipid radicals and lipid peroxyl radicals, contrary to a previous report. At concentrations lower than 5 microM, Mn2+ competitively inhibited Fe(2+)-pyrophosphate-supported lipid peroxidation in liposomes consisting of phosphatidylcholine with arachidonic acid at the beta-position and phosphatidylserine dipalmitoyl, and reduced nicotinamide adenine dinucleotide phosphate (NADPH)-supported lipid peroxidation in the presence of iron complex in microsomes. Iron reduction responsible for lipid peroxidation in microsomes was not influenced by Mn2+.
authors.affiliation: Division of Environmental Hygiene, Hokkaido Institute of Pharmaceutical Sciences, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Tampo
authors.forename: M
authors.initials: M
authors.lastname: Yonaha
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D005609:Free Radicals / Q000378:metabolism; D066298:In Vitro Techniques; D007501:Iron / Q000494:pharmacology; D015227:Lipid Peroxidation / Q000187:drug effects*; D008081:Liposomes; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D008345:Manganese / Q000494:pharmacology*; D008862:Microsomes, Liver / Q000187:drug effects / Q000378:metabolism; D009249:NADP / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects; D010743:Phospholipids / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D000975:Antioxidants; D005609:Free Radicals; D008081:Liposomes; D010743:Phospholipids; D008345:Manganese; D008315:Malondialdehyde; D009249:NADP; D007501:Iron