Comprehensive Review on Targeting Breast Cancer through Medicinal Plants

Breast cancer is a disease characterized by biological heterogeneity, recurrence, metastasis, resistance to treatment, and therapy-associated toxicity. Plants used in medicine contain compounds with different chemical properties that have been studied for their impact on proliferation, apoptosis, cell cycle progression, migration, invasion, angiogenesis, and oncogenic signaling. The purpose of this review is to critically analyze five medicinal plants (Curcuma longa, Withania somnifera, Camellia sinensis, Azadirachta indica, and Catharanthus roseus) with special focus on major constituents, breast cancer models, mechanisms of action, translational data, and limitations. Curcuminoids, withaferin A, epigallocatechin-3-gallate (EGCG), nimbolide, and vinca alkaloids are distinct classes of compounds with considerable amount of experimental data. Nevertheless, the level of evidence varies greatly, as a large number of studies involve pure compounds at concentrations which cannot be easily achieved in humans, and also due to differences in composition, plant part, extraction procedure, and standardization of plant extracts. Clinical evidence is much less extensive than cell line and animal evidence for most of the candidates. Vinca alkaloids represent a unique case as these compounds obtained from the plants are already established anticancer agents, but this does not imply that crude C.roseus preparations can be used in breast cancer. [1–3, 7, 11, 17, 19, 26–29]