Cytotoxic effects of plants used in the treatment of breast cancer: A systematic review

Breast cancer is a multifactorial disorder with a major impact on populations worldwide. Because approved medicines such as tamoxifen, fulvestrant, and doxorubicin can produce adverse effects, medicinal plants continue to be investigated as alternative sources of breast-cancer treatments. This systematic review examined articles published from 2015 to 2021 and retrieved through PubMed, ScienceDirect, and Google Scholar. The review identified and reorganized evidence on the cytotoxic potency of plant extracts and compounds tested against MCF-7 and T47D breast-cancer cell lines. Extracts were classified as having high, moderate, or low activity according to their half-maximal inhibitory concentration (IC₅₀), with tamoxifen used as a reference treatment. The highest activity against MCF-7 cells was reported for the methanolic leaf extract of Sideroxylon oxyacanthum (Sapotaceae; IC₅₀ = 0.09±0.02 μg/mL). Asteraceae was the most frequently represented plant family. For T47D cells, the highest activity was reported for Fraction A of the ethyl-acetate leaf fraction of Ficus septica Burm. (Moraceae; IC₅₀ = 2.57 μg/mL). The evidence most frequently concerned Sapotaceae, Flacourtiaceae, Ranunculaceae, Verbenaceae, Lamiaceae, Asteraceae, and Moraceae, whereas fewer data were available for Convolvulaceae, Thymelaeaceae, and Orchidaceae. Further controlled studies are required to validate promising plant-derived cytotoxic candidates and determine their selectivity and mechanisms of action.