Anticancer compounds production in Catharanthus roseus by methyl jasmonate and UV-B elicitation

Catharanthus roseus is a very rich source of medically important alkaloids. However, since their concentrations are extremely low in plant tissues, many efforts have been made to increase the alkaloids level - among them are the application of various elicitors. Since the alkaloids are synthetized by a complex pathway, the detailed knowledge of the molecular background of the system is essential. The current job aimed to study the effect of two elicitor, methyl jasmonate (MeJa) and UV-B irradiation, and also their simultaneous effect, on the expression patterns of two key synthesis-involved genes, namely tryptophan decarboxylase and strictosidine synthase through quantitative RT-PCR. Estimation of vinblastine, vincristine and ajmalicine, was carried out using high performance liquid chromatography (HPLC) in the elicited plant leaves. From the obtained results, it was concluded, that these two elicitors act on different way, and also their combined application induces the tryptophan decarboxylase but in less for the strictosidine synthase gene expression in the treated Catharanthus roseus leaves. The results showed that the combination of MeJa and UV-B light (MU) induces higher accumulation of vinblastine,vincristine and ajmalicine than other treatments. Vinblastine content with MU60 treatment showed higher level during the third day of exposure to the combined elicitors (methyl jasmonate and UV-B). Vincristine accumulation was the highest after one day of exposure to MU60 treatment. Its content was increased 6-fold than control after one day exposure to the combined elicitors. Additionally, it could be observed that MU60 treatment, was the best for ajmalicine accumulation. Ajmalicine content was increased 8-fold than control at 60 min exposure to the combined elicitors. As a final outcome, we also conclude that the effect of the different elicitations is highly dependent on the experimental parameters.