Screening of Anti-breast Cancer and Anti-oxidant Potentials of Selected Medicinal Plants from Sri Lanka

Aim: To identify anti- breast cancer potential of medicinal plants used in Sri Lanka. Study Design: The anti-proliferative and cytotoxic potentials of solvent extracts from leaves and bark of seven medicinal plants from Sri Lanka were investigated against estrogen receptor (ER) positive (MCF-7 cell line), triple negative (MDA-MB-231 cell line) breast cancer subtypes and normal mammary epithelial cells (MCF-10A cell line) in-vitro. Additionally, the anti-oxidant activity, phenolic, and flavonoid contents of the extracts were determined. Methodology: The anti-proliferative activity of the extracts was determined using Sulforhodamine B assay. The anti-oxidant activity was measured using 2, 2-di (4-tert-octylphenyl)-1-picrylhydrazyl (DPPH) radical scavenging assay and Ferric ion reducing antioxidant power (FRAP) assay. The Flavonoid and polyphenol contents were assessed using AlCl3 and Folin-Ciocalteu reagents, respectively. Results: Extracts of Erigeron sp, Gardenia crameri, Canarium zeylanicum, Elaeocarpus subvillosus and Angiopteris evecta exerted high anti-proliferative potentials (half maximal inhibition concentration IC50 <100 µg/ mL) with less cytotoxicity to normal mammary epithelial cells. Most selective, potent extracts against MCF-7 and MDA-MB-231 cancer cell lines, were dichloromethane extracts of A. evecta leaves (IC50 = 43.74 µg/ mL) and C. zeylanicum bark (IC50 = 44.75 µg/ mL) respectively. All methanol extracts, except those from A. evecta and A. variabilis exhibited potent anti-oxidant activity and high poly-phenolic content in Galic acid equivalents (>50 mg/g). Comparatively high flavonoid quercetin equivalents (> 100 mg/ g) content was observed in dichloromethane extracts of Erigeron sp. leaves and bark. Conclusion: Five of the seven studied plants demonstrate potential for use in cancer treatment. The phytochemicals responsible for the anti-cancer activity of these plants may not include polyphenols and flavonoids. However, the extracts with high anti-oxidant potentials, primarily attributed to the polyphenolic compounds present. In the future, these extracts could be used to isolate potential anti-breast cancer and anti-oxidant compounds for drug development. Furthermore, the study adds scientific value for traditional remedies and decoctions.