Natural Bioactive Compounds as Emerging Therapeutic Molecules Against Breast Cancer: Emphasis on the Role of Phytoestrogens

Background: Breast cancer is the leading form of cancer in women, which is also hormone-dependent. Depending on the receptor expression, these cancers are subdivided into different forms, and among these receptors, estrogen, progesterone, and Her2 are the important ones. Targeting breast cancer (BC) has been difficult due to their varied nature; however, various phytocompounds, especially those having estrogen-like properties, have proven to be effective. Objective: The present review is aimed to provide a detailed description of various Phytocompounds inhibiting breast cancer proliferation and progression; emphasis has been given to the role of phytoestrogens with their molecular mechanism of action. Methods: The data were collected from reputed databases, such as PubMed/Medline, Web of Science, Science Direct, Eurekaselect, etc. Data on the phytoestrogens were collected using individual names and "phytoestrogens" as keywords. Articles published in journals, which are not indexed by Thomson Reuters (SCI/SCIE/ESCI), were omitted. Results: Natural products are important drug candidates against multiple forms of breast cancer. In addition to the initiation and proliferation events, these molecules inhibit epithelial to mesenchymal transition (EMT) and metastasis of BC. Phytoestrogens are an important class of compounds which have known estrogenic potential; studies have also indicated the anticancer potentials of these molecules in cell culture and animal models of BC. Conclusion: Natural plant compounds, especially phytoestrogens, are promising anti-breast cancer agents that induce cell cycle arrest, apoptosis, and autophagy-mediated cell death. However, more clinical studies are necessary so that these molecules can be used as commercial drug molecules.