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 ascompared to the isolated camptothecin from O. decumbens (CPT-Od) and N. foetida (CPT-Nf). CPT isolatedfrom 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 IC₅₀of 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.