Cytotoxic activity of extracts and crude saponins from Zanthoxylum armatum DC. against human breast (MCF-7, MDA-MB-468) and colorectal (Caco-2) cancer cell lines

Background: Zanthoxylum armatum DC has been an important traditional plant known for its medicinal properties. It is well known for its antimicrobial, larvicidal and cytotoxic activities. Methods: The potential anticancer effects of the methanol extract and the crude saponins from fruit, bark and leaves of Z. armatum on breast (MDA-MB-468 and MCF-7) and colorectal (Caco-2) cancer cell lines using MTT, neutral red uptake(NRU) and DAPI stain assays were evaluated. Results: In MTT assay the methanol extract of fruit (Zf), bark (Zb) and leaves (Zl) of Zanthoxylum armatum, showed significant and dose dependent growth inhibition of MCF-7, MDA MB-468 and Caco-2 cancer cell lines in a dose of 200 ae g/ml and above. The saponins (Zf. Sa, Zb. Sa and Zl. Sa) showed significant activity against MDA MB-468 (95, 94.5 and 85.3%) as compared to MCF-7 (79.8, 9.43, 49.08%) and Caco-2 (75.8, 61.8, 68.62%) respectively. The extracts were further tested in more sensitive NRU assay and its was found that Zf extract showed higher cytotoxic activity as compared to Zb and Zl extracts with 100 ae g/ml concentration. The breast cancer cell lines showed more sensitivity toward the crude saponins from fruit and bark with maximum inhibition of up to 93.81(+/- 2.32) % with respect to 71.19(+/- 2.76) of Actinomycin-D. DAPI staining experiment showed that saponins from fruit induced apoptosis mode of cell death in all three types of cell lines while saponins form leaves and bark showed similar results against MDA MB-468 indicated by nuclear fragmentation and chromatin condensation. The effect of saponins from fruit, bark and leaves (Zf. Sa, Zb. Sa and Zl. Sa) against Caco-2 cell lines inhibited the growth of Caco-2 by 53.16 (+/- 3.31) %, 66.43 (+/- 3.24) and 45.96 (+/- 10.67) respectively with respect to Actinomycin-D (4 mu M) which showed the growth inhibition of 65.40(+/- 4.29) %. Conclusion: The current study clearly demonstrates that the extract and crude saponins from fruit, bark and leaves of traditional medicinal plant Zanthoxyllum armatum DC., has the potential to exert its cytotoxic effect on cancer cell lines isolated form human by a mechanism involving apoptosis. The overall finding demonstrate that this plant specially fruits, could be potential source of new anticancer compounds for possible drug development against cancer.