Chemical interactions between thiamin and tannic acid. II. Separation of products.

Bio Rex 70 column chromatography and high voltage paper electrophoresis were used to fractionate and define the reaction products of thiamin-tannic acid and thiamin-tea mixtures. Fractions separated indicated the presence of (a) thiamin-tannic acid adduct(s) and several modified forms of thiamin among the products. Using radioactive thiamin and determining the intact form by scintillation counting, the extent of thiamin modification under various conditions was compared with previous results as determined by the thiochrome method. The elution profile of the thiamin-tea mixture and the electrophoretogram showed features similar to those of the thiamin-tannic acid mixture. The effectiveness of the tea extract and tannic acid in modifying thiamin was compared. Ascorbic acid was found to protect the modification of thiamin by tannic acid, not only at acidic pH as previously found, but also at neutral pH, thus making vitamin C a strong candidate for the protection of thiamin in the alimentary system.