Kinetics of thiamine-polyphenol interactions and mechanism of thiamine disulphide formation.

Interactions between thiamine and antithiamine polyphenolic compounds exhibit similar pseudo-first order rate constants and Arrhenius activation energy. Probably, hydroxide ions open the thiazole moiety of thiamine to give a sulphydryl derivative existing in equilibrium with thiamine. Ionization and air oxidation of the polyphenols yield oxidized forms which may be quinones and others. Catalytic and rapid oxidation by the quinones lead to formation of thiamine disulphide from the sulphydryl derivative shifting the equilibrium away from thiamine.