Studies on the formation of carthamin in buffer solutions containing precarthamin and oxidizing agents

Abstract

Formation of carthamin was investigated in bufferized solution containing precarthamin and oxidizing agents. KMnO4, H2O2 and HIO4, were stimulators for carthamin formation. K2Cr2O7 Mn02, Ag2O, SeO2, and CrO3 on the other hand, showed little or no activity in the catalytic carthamin synthesis. KMnO4 was very sensitive to precarthamin, while both H2O2 and HIO4 were insensitive. The optimal pH value for carthamin formation by KMnO4, was 5.3 in 50.0 mM citrate buffer. Antioxidants such as hydroquinone, L-ascorbic acid and D-araboascorbic acid completely inhibited the oxidative conversion of precarthamin to carthamin at a low concentration.

Keywords

• carthamin
• carthamin formation
• oxidizing agents