title: Saliva plays a dual role in oxidation process in stomach medium.
abstract: The aim of this study was to evaluate the role of saliva in the oxidation process under the acidic condition of the stomach. Saliva specimens played varied roles in the lipid peroxidation process of heated muscle tissue in simulated gastric fluid: pro-oxidant effects, no effects, and antioxidant effects. To elucidate these differences, selected saliva components were examined. The pseudoperoxidase activity of lactoperoxidase increased lipid peroxidation, while thiocyanate and nitrite-reduced lipid peroxidation. The effect of a saliva specimen on lipid peroxidation was correlated with the concentration of nitrite in the specimen, but not with that of other saliva components. The inhibitory effect of nitrite may be due to its conversion to NO. Elucidation of the antioxidant effect of saliva on co-oxidation of d-alpha-tocopherol in gastric fluid, demonstrated that saliva alone cannot protect d-alpha-tocopherol from co-oxidation, although it partially protected against lipid peroxidation. The presence of red wine polyphenols in stomach medium totally inhibits food lipid peroxidation and d-alpha-tocopherol co-oxidation.
authors.affiliation: Department of Pharmaceutics, School of Pharmacy, The Hebrew University of Jerusalem, POB 12065, Jerusalem 91120, Israel.
authors.forename: S
authors.initials: S
authors.lastname: Gorelik
authors.forename: R
authors.initials: R
authors.lastname: Kohen
authors.forename: M
authors.initials: M
authors.lastname: Ligumsky
authors.forename: J
authors.initials: J
authors.lastname: Kanner
mesh_terms: D000328:Adult; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D005419:Flavonoids / Q000378:metabolism; D005753:Gastric Mucosa / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D015227:Lipid Peroxidation; D008054:Lipid Peroxides / Q000378:metabolism; D008460:Meat / Q000032:analysis; D010084:Oxidation-Reduction; D010306:Parotid Gland / Q000378:metabolism; D010636:Phenols / Q000378:metabolism; D059808:Polyphenols; D011200:Poultry; D012463:Saliva / Q000737:chemistry / Q000378:metabolism*; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D014920:Wine / Q000032:analysis; D024502:alpha-Tocopherol / Q000378:metabolism
chemical_list: D000975:Antioxidants; D005419:Flavonoids; D008054:Lipid Peroxides; D010636:Phenols; D059808:Polyphenols; D017392:Thiobarbituric Acid Reactive Substances; D024502:alpha-Tocopherol