Formation of an oxathiolone compound from rutin in acidic mixture of saliva and buckwheat dough: Possibility of its occurrence in the stomach

摘要

Buckwheat is used for various foods in the world. The objective of the present study is the determination of the chemical structure of a product formed in the acidic mixture of buckwheat dough and saliva that contains both nitrite and thiocyanate. In the mixture, an oxathiolone derivative of rutin, 5,7-dihydroxy-2-(7-hydroxy-2-oxobenzo[d][ 1,3]oxathioi-4-yl)-4H-chromen-4-one-3-O-β-rutinoside, was found. This compound seemed to be formed by the hydroiysis of a 2'-thiocyanate derivative of rutin, which was produced by the reaction of thiocyanate with the o-quinone generated by nitrous acid-dependent oxidation of rutin. Importance of the formation of the oxathiolone compound is discussed in relation to scavenging of the toxic quinone in the stomach.