Effect of light and methyl jasmonate on the accumulation of anticancer compounds in cell suspension cultures of Catharanthus roseus

Background and objectives Catharanthus roseus (Apocynaceae) is a medicinal plant that contains unique compounds used in cancer treatment. This investigation deals with enhancing the production of anticancer compounds (ajmalicine, vinblastine, and vincristine) in cell suspension cultures through elicitation by methyl jasmonate and light and dark treatments. Materials and methods For callus induction, leaf segments were cultured on solidified Murashige and Skoog (MS) medium with different 2,4-D and kin supplementations. Actively growing leaf was used for initiation of cell suspension culture by transferring 1 g of tissues in 100 ml Erlenmeyer flasks containing 20 ml liquid MS medium supplemented with 1.0 mg/l 2.4-D+1.0 mg/l kin. Different concentrations of MeJA (100, 200 and 300 μM) were added to cell suspension culture. Cell tissues were harvested at 2 and 4 days after elicitation. For light and dark elicitation, cell suspension culture was performed in 250 ml conical flasks containing 50 ml of liquid medium and inoculated with 1 g fresh calli, subjected to 16 h photoperiod and complete darkness; then callus tissues were collected at 2 and 4 days after elicitation. Estimation of ajmalicine, vinblastine, and vincristine was carried out using high-performance liquid chromatography in the elicited cultures compared with untreated calli. Results and conclusion Callus of C. roseus was produced from young leaves on MS medium with 1.0 mg/l of each 2,4-D and kin that recorded high callus initiation frequency (%). In cell suspension culture, viability of cells increased gradually with time until it reached their maximum at day 20 of culture, then declined until 30 day of culture. Adding methyl jasmonate (100 µM) showed higher level of ajmalicine after 2 days of culture and increased 19-fold than the control. The vinblastine content was decreased at 200 µM methyl jasmonate when cultures were treated for 2 days. With regard to vincristine accumulation in cell suspension, it was observed that there was no difference in the accumulation of vincristine. For light and dark exposure, it could be observed that cultures exposed to light condition gave the best results of ajmalicine and vincristine than cultures exposed to dark conditions, while the vinblastine content was better under dark at 2 or 4 days. In conclusion, the results suggest that methyl jasmonate efficiently enhances both of ajmalicine and vinblastine especially after 2 days, while for vincristine, there was n