title: Glutathione peroxidase mimics as novel antioxidants from vegetables.
abstract: Vegetables are generally recognized as rich sources of dietary antioxidants for inhibiting lipid peroxidation. Here we investigated lipid hydroperoxide (LOOH)-reducing activity of several vegetables to estimate their role on the prevention of lipid peroxidation in food and the digestive tract. By using HPLC analysis, we screened vegetables possessing the ability to convert 13-hydroperoxyoctadecadienoic acid (13-HPODE) to its reduced derivative, 13-hydroxyoctadecadienoic acid (13-HODE). Welsh onion (Allium fistulosum L.) was found to be highly active in the reduction of 13-HPODE among tested vegetables. There was no relationship between 13-HPODE reducing activity and GSH peroxidase (GPX) activity in the tested vegetables. 13-HPODE-reducing activity of welsh onion was enhanced by the addition of sulfhydryl compounds including glutathione (GSH). Neither GPX inhibitor nor heat treatment suppressed 13-HPODE-reducing activity effectively. These results suggest that welsh onion and other vegetables contain GPX mimics responsible for the reduction of LOOH. GPX mimics may be helpful in the attenuation of harmful effect of LOOH from food.
authors.affiliation: Department of Food Science, Graduate School of Nutrition and Biosciences, The University of Tokushima, Kuramoto-cho 3, Tokushima 770-8503, Japan. terao@nutr.med.tokushima-u.ac.jp
authors.forename: Junji
authors.initials: J
authors.lastname: Terao
authors.forename: Mio
authors.initials: M
authors.lastname: Hiwada
authors.forename: Keiko
authors.initials: K
authors.lastname: Taguchi
authors.forename: Keigo
authors.initials: K
authors.lastname: Takahara
authors.forename: Satoshi
authors.initials: S
authors.lastname: Mohri
mesh_terms: D000975:Antioxidants / Q000378:metabolism* / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005502:Food; D005979:Glutathione Peroxidase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006358:Hot Temperature; D008041:Linoleic Acids / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D008054:Lipid Peroxides / Q000378:metabolism; D019697:Onions / Q000737:chemistry / Q000201:enzymology; D010084:Oxidation-Reduction; D013438:Sulfhydryl Compounds / Q000494:pharmacology; D014675:Vegetables / Q000201:enzymology*
chemical_list: D000975:Antioxidants; D004791:Enzyme Inhibitors; D008041:Linoleic Acids; D008054:Lipid Peroxides; D013438:Sulfhydryl Compounds; C038649:13-hydroperoxy-9,11-octadecadienoic acid; C024348:13-hydroxy-9,11-octadecadienoic acid; D005979:Glutathione Peroxidase