A simple and rapid HPLC-DAD method for simultaneously monitoring the accumulation of alkaloids and precursors in different parts and different developmental stages of Catharanthus roseus plants.

Abstract

A rapid and simple reversed phase liquid chromatographic system has been developed for simultaneous analysis of terpenoid indole alkaloids (TIAs) and their precursors. This method allowed separation of 11 compounds consisting of eight TIAs (ajmalicine, serpentine, catharanthine, vindoline, vindolinine, vincristine, vinblastine, and anhydrovinblastine) and three related precursors i.e., tryptophan, tryptamine and loganin. The system has been applied for screening the TIAs and precursors in Catharanthus roseus plant extracts. In this study, different organs i.e., flowers, leaves, stems, and roots of C. roseus were investigated. The results indicate that TIAs and precursor accumulation varies qualitatively and quantitatively in different organs of C. roseus. The precursors showed much lower levels than TIAs in all organs. Leaves and flowers accumulate higher level of vindoline, catharanthine and anhydrovinblastine while roots have higher level of ajmalicine, vindolinine and serpentine. Moreover, the alkaloid profiles of leaves harvested at different ages and different growth stages were studied. The results show that the levels of monoindole alkaloids decreased while bisindole alkaloids increased with leaf aging and upon plant growth. The HPLC method has been successfully applied to detect TIAs and precursors in different types of C. roseus samples to facilitate further study of the TIA pathway and its regulation in C. roseus plants.