Effects of pH, Metal Ions and Ascorbic Acid on the Formation of Yellow Pigments from Tetrahydro-β- Carboline Derivative

Abstract

The effects of pH metal ions and ascorbic acid on the formation of yellow pigments from 1-(2'-pyrrolidinethion-3'-y1)-1, 2, 3, 4tetrahydro- β-carboline-3-carboxylic acid (PTCC) were investigated by using UV spectrometry and HPLC analyses. The formation of yellow pigments was enhanced with increasing pH of the reaction mixture. The presence of Fe (II) and Cu (II) (50μM) increased the formation of yellow pigments a little, but the addition of ascorbic acid (5mM) decreased it. When a methanol solu- tion of the yellow pigments was subjected to Sephadex LH-20 column chromatography, their discolorlation was observed. As a result, a paper chromatography showed that the yellow pigments were consisted of three fluorescent components. From the UV spectral and the fluorescent characteristics, it was presumed that these compounds have β-carboline as a common structural moiety.