Cell line selection combined with jasmonic acid elicitation enhance camptothecin production in cell suspension cultures of Ophiorrhiza mungos L.

Abstract

Ophiorrhiza mungos is a herbaceous medicinal plant which contains a quinoline alkaloid, camptothecin (CPT), an anticancer compound. A high-yielding cell line, O. mungos cell line-3 (OMC3) was selected from cell suspension cultures of O. mungos using cell aggregate cloning method and established cell suspension culture. OMC3 cell suspension produced significantly high biomass (9.25±1.3g/flask fresh weight (FW)) and CPT yield (0.095±0.002mgg-1 dry weight (DW)) compared with the original cell suspension. Inoculum size of OMC3 cell suspension culture was optimised as 14gL-1. Media optimisation has shown that 5% (w/v) sucrose and an increased ammonium/nitrate concentration of 40/20mM favoured CPT production, whereas 3% (w/v) sucrose, an ammonium/nitrate concentration of 20/40mM and 1.25mM of phosphate favoured biomass accumulation. Jasmonic acid, chitin and salicylic acid was used to elicit CPT production in the original cell suspension culture and achieved significantly high CPT production with jasmonic acid (JA) elicitation. Further, OMC3 cell suspension culture was elicited with JA (50μM) and obtained 1.12±0.08mgg-1 DW CPT and 9.52±1.4g/flask FW (190.4gL-1 FW). The combination of cell line selection and elicitation has produced 18.66-fold increases in CPT production together with significantly high biomass yield. The study is helpful in the scale-up studies of O. mungos cell suspension culture in suitable bioreactor systems for the production of CPT.