Multiple shoot cultures of Ophiorrhiza rugosa var. decumbens Deb and Mondal--a viable renewable source for the continuous production of bioactive Camptotheca alkaloids apart from stems of the parent plant of Nothapodytes foetida (Wight) Sleumer.
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Abstract
Camptotheca alkaloids were isolated from multiple shoot cultures of O. decumbens (0.056% dry weight) and stems of N. foetida. The cytotoxicity of the extracts and products were tested in a panel of five cell lines. Crude extract from O. decumbens (Cr-Od) and N. foetida (Cr-Nf) showed more potent cytotoxic activity as compared to the isolated camptothecin from O. decumbens (CPT-Od) and N. foetida (CPT-Nf). CPT isolated from shoot cultures contained biological activity suggesting the possibility of using this system of O. decumbens as a renewable source for the production of camptotheca alkaloids. 9-Methoxy camptothecin (9-mCPT), isolated from N. foetida, was a very effective cytotoxic agent as compared to Cr-Nf or CPT-Nf. The IC50 of 9-mCPT was 0.84, 0.32, and 0.35 μg/ml for A549, MCF7 and Jurkat cell lines and >3 μg/ml for U937. Viability assays using MTT dye were further confirmed by assessing extent of apoptosis in these cells. These findings suggest that shoot cultures of O. decumbens offer a rich alternative plant source for the anticancer compound, CPT and 9-mCPT is a more potent compound in N. foetida as compared to CPT.