Cytotoxic, Antioxidant and Apoptotic Effects of Twenty Sri Lankan Endemic Plants in Breast Cancer Cells

Aims: Main aim of this study was to evaluate cytotoxic, antioxidant and apoptotic properties of Sri Lankan endemic plants in estrogen receptor positive (MCF-7) breast cancer and triple negative breast cancer (MDA-MB-231) cells.

Place and Duration of Study: At the Institute of Biochemistry, Molecular Biology and Biotechnology, between June 2013 and May 2015.

Methodology: We investigated leaf and bark extracts (hexane, chloroform, ethyl acetate, methanol) of twenty endemic plants for possible cytotoxicity against breast cancer (on estrogen receptor positive MCF-7 and triple negative MDA-MB-231 breast cancer) cell lines and normal mammary epithelial cells (MCF-10A). Cytotoxic extracts were also investigated for possible apoptotic effects on MDA-MB-231 cells by caspase 3/7 estimation. Total polyphenols, flavonoids and the free radical scavenging activity of the extracts were also measured.

Results: Of the 156 solvent extracts from 20 plants studied only 35 extracts from 14 plants were significantly cytotoxic [18 extracts to MCF-7 cells (IC50 31.43 to 97.50 µg/mL), 7 extracts to MDA-MB-231 cells (IC50 16.11 to 95.83 µg/mL) and 10 extracts (IC50 0.51 to 99.35 µg/mL) to both cell lines] with only some of these being less cytotoxic to normal breast epithelial cells. Caspase 3/7 was activated by some of the cytotoxic extracts. Polyphenol and free radical scavenging activity were high in most of the methanol and ethyl acetate extracts. Flavonoids were present in all the extracts in varying quantities.

Conclusion: The cytotoxic and apoptotic potential demonstrated by some plants endemic to Sri Lanka, indicates strong leads for future drug discovery for combating breast cancer.