title: Reactions of thiocyanate in the mixture of nitrite and hydrogen peroxide under acidic conditions: investigation of the reactions simulating the mixture of saliva and gastric juice.
abstract: Nitrite and SCN(-) in saliva can mixes with H(2)O(2) in the stomach. The mixing can result in the formation of ONOOH. It is not yet known how salivary SCN(-) reacts with ONOOH. An objective of the present study was to elucidate the reaction between ONOOH and SCN(-). In nitrite/H(2)O(2) systems at pH 2, SCN(-) inhibited the consumption of nitrite and the formation of O(3)(-). SCN(-) enhanced the decomposition of ONOOH and H(2)O(2) in HNO(2)/H(2)O(2) systems. Accompanying the reactions, sulfate was formed, suggesting that ONOOH oxidized SCN(-). SCN(-) inhibited the nitration of phenolics induced by HNO(2)/H(2)O(2). The inhibition is discussed taking SCN(-)-dependent reduction of ONOOH to HNO(2) into consideration. SCN(-) also inhibited H(2)O(2)-induced consumption of nitrite and nitration of phenolics in acidified saliva. The result obtained in this study suggests that salivary SCN(-) can reduce ONOOH to O(2)(-)/HNO(2) inhibiting nitrating reactions in the stomach.
authors.affiliation: Department of Bioscience, Kyushu Dental College, Kitakyushu, Japan. takahama@kyu-dent.ac.jp
authors.forename: Umeo
authors.initials: U
authors.lastname: Takahama
authors.forename: Mariko
authors.initials: M
authors.lastname: Tanaka
authors.forename: Takayuki
authors.initials: T
authors.lastname: Oniki
authors.forename: Sachiko
authors.initials: S
authors.lastname: Hirota
mesh_terms: D000143:Acids / Q000378:metabolism*; D005750:Gastric Juice / Q000737:chemistry*; D005753:Gastric Mucosa / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D018716:Molecular Mimicry; D009573:Nitrites / Q000494:pharmacology*; D016877:Oxidants / Q000494:pharmacology*; D010084:Oxidation-Reduction; D012463:Saliva / Q000737:chemistry*; D013861:Thiocyanates / Q000494:pharmacology*
chemical_list: D000143:Acids; D009573:Nitrites; D016877:Oxidants; D013861:Thiocyanates; D006861:Hydrogen Peroxide