Synthesis of anti-tumor dimeric indole alkaloids in catharanthus roseus was promoted by irradiation with near-ultraviolet light at low temperature

We have found that coupling between catharanthine and vindoline occurs non-enzymatically in the presence of flavin mononucleotide and manganese ions with near- ultraviolet light irradiation in vitro. The present study found that the concentrations of catharanthine and vindoline in Catharanthus roseus decreased and those of dimeric indole alkaloids increased under near- ultraviolet light at 4 °C. It indicates that this coupling reaction at 4 °C occurs non-enzymatically.