Cytotoxic and apoptotic potential of potato glycoalkaloids in a number of cancer cell lines

There is conflicting evidence that potato glycoalkaloids may have potential anticancer activity. The aim of this study was to screen potato glycoalkaloids for cytotoxicity in a range of cancerous cell lines. IC50 values (µg/ml) for each glycoalkaloid were calculated in six human cancerous cell lines including Jurkat T lymphocytes, U937 leukemic monocyte lymphoma cells, Caco-2 epithelial colorectal cells, HepG2 liver cells, HFFF2 foetal foreskin fibroblasts and MCF-7 breast cells. Cytotoxicity in a non-cancerous human colon cell line was also investigated. As expected, α-chaconine was the most cytotoxic glycoalkaloid across all cell lines. When compared to therapeutic drugs, α-chaconine has similar inhibitory effects to tamoxifen on cell viability. However, Hoechst staining and caspase analysis indicate that α-chaconine does not appear to inducing apoptotic cell death. Additionally, α-solanine and solanidine did not appear to possess strong apoptotic potential. In contrast, the therapeutic drugs, doxorubicin and tamoxifen did result in apoptotic morphological changes in U937 cells with an increase in caspase activity. Flow cytometry and DNA fragmentation assays confirmed the poor apoptotic potential of glycoalkaloids compared to the therapeutic drug tamoxifen. The cytotoxic profile of glycoalkaloids is apparent; however the mode of action underlying cell death for glycoalkaloids does not appear to be via an apoptotic pathway.