Myricetin induces apoptosis mediated by oxidative stress in 4T1 and E0771 mammary cancer cells

Background: Myricetin is a polyphenolic compound that is cytostatic and/or cytotoxic for several cancer cell types; however, little is known about its effect on mammary carcinoma cells. Objective: The objective of this study is to determine whether myricetin affects the growth of mammarycarcinoma cells. Results: Myricetin inhibited the growth of 4T1 and E0771 mouse mammary carcinoma cells to a greater extent than either resveratrol or epigallocatechin-3-gallate, which are also present in red wine and green tea, respectively, and also have anti-cancer activities. Reduced growth of myricetin-treated 4T1 and E0771 cells was the result of apoptosis that was associated with disruption of the outer membrane of mitochondria. Myricetin-induced apoptosis of 4T1 and E0771 cells was prevented by the antioxidant N-acetyl cysteine, indicating that cytotoxicity was the result of oxidative stress caused by the accumulation of reactive oxygen species. Conclusion: We conclude that the pro-oxidant action of myricetin and ensuing apoptosis of mammary carcinoma cells indicate that myricetin may be useful in breast cancer treatment.