Tissue culture of Ophiorrhiza mungos L., a prospective method for the production of an anticancer drug, camptothecin

Abstract

Camptothecin (CPT), a cytotoxic quinoline indole alkaloid, is an anticancer compound. Its two major semi synthetic derivatives, topotecan and irinotecan, are Food and Drug Administration (FDA) approved drugs effectively used for treating different cancer types and sold under the trade names Hycamtin and Camptosar. Among the Ophiorrhiza species, Ophiorrhiza mungos contains the highest CPT level (0.02 % g dw). CPT level was determined in plants before flowering (0.074 ± 0.003 % g dw) and at flowering (0.052 ± 0.002 % g dw). Multiple shoot cultures were induced on seedling-derived explants of O. mungos in half strength MS solid media supplemented with 1.0 mg/L BAP to obtain 12.00 ± 1.22 shoots in 20 days. Repeated subcultures at 20 days interval yielded 20.00 ± 3.71 shoots/subculture of shoot clusters. After elongation, rooting and transplanting, the growth of shoot clusters were studied in both in vitro and same aged naturally grown seedlings. Highest biomass (4.62 ± 0.158 g fw) was obtained in in vitro-derived shoot clusters. CPT increased according to biomass and the maximum CPT was recorded in in vitro rooted shoot clusters after 15 days (0.031 ± 0.001 % g dw). Hence, in vitro-derived rooted shoot clusters of O. mungos cultivated in net-pots for 60 days under shade net house conditions found to be a sustainable source for CPT.