Natural Products as Promising Antitumoral Agents in Breast Cancer: Mechanisms of Action and Molecular Targets.

Extensive research over the past several decades has identified numerous dietary and phytochemical compounds that have chemopreventive potential and could represent an important source of anti-cancer lead molecules. In this scenario several nutritional factors have attracted considerable attention as modifiable risk factor in the prevention of breast cancer, the most frequently diagnosed cancer and a major cause of death among women worldwide. There is an immediate need for more effective and less toxic therapeutic and preventive strategies for breast cancers able also to counteract the recurrent phenomenon of resistance to hormonal and targeted therapy that represent the first-line treatment in the management of breast cancer patients. The present review focuses on chemopreventive and anti-cancer activities of different bioactive compounds obtained from dietary sources such as Omega-3 fatty acids, naturally present in fish, Resveratrol (3,5,40-trihydroxy-transstilbene), a phytoalexin found in grapes and Epigallocatechin Gallate, a polyphenolic compound found in green tea, or purified from medicinal plant (Oldenlandia Diffusa) and fruits (Ziziphus Jujube) highlighting their potential use in breast cancer treatment. Herein, we discuss the molecular mechanisms by which the bioactive compounds can inhibit carcinogenesis by regulating antioxidant enzyme activities, and inducing antiproliferative and apoptotic effects in different breast cancer cell lines. Understanding the mechanism of action of dietary compounds or traditionally used herbs having potential preventive and therapeutic effects on cancer may provide a rationale for further translational studies. This review emphasizes the importance, in the next future, of a proper scientific validation of these natural bioactive compounds for clinical use in the therapeutic portfolio for breast cancer.