Effect of dyes on the photodecomposition of pyridoxine and pyridoxamine

Abstract

Abstract Erythrosine, eosine Y, rose bengal, mercurochrome, methylene blue, azure A and azure B accelerated the photodecomposition of pyridoxine and pyridoxamine at pH 5–9, but fluorescein and acid red did not. The photodecomposition of pyridoxine in the presence of erythrosine was greatest at pH 9·0, The singlet oxygen generated by light-excited dyes played a role as a mediator in the decomposition of pyridoxine but the degradation products of erythrosine had no effect. The photodecomposition of pyridoxine and pyridoxamine in the presence of dyes was depressed by aminopyrine, sulpyrine and tryptophan. Pyridoxine 3, 4′-dioctanoate was stable in the presence of erythrosine.