Deodorizing Mechanism of (-)-Epigallocatechin Gallate against Methyl Mercaptan

Abstract

The deodorizing mechanism of (-)-epigallocatechin gallate (EGCg), the main constituent of a green tea extract, against methyl mercaptan (CH₃SH) was investigated. EGCg showed deodorizing activity against CH₃SH by a chemical reaction between EGCg and CH₃SH. The non-volatile reaction products were identified to be compounds introducing a methylthio and/or a methylsulfinyl group into the B ring of EGCg, and gaseous oxygen was necessary for deodorizing activity. From these results, it was assumed that the deodorizing mechanism of EGCg was due to the addition of a methylthio group to the ortho-quinone generated by atmospheric oxygen. It was also found that secondary compounds produced by the reaction between EGCg and CH₃SH had a stronger deodorizing activity than that of EGCg itself.