The tropical red mangrove Rhizophora mucronata (Lam.) has been widely used as an astringent, antiseptic, antibacterial, anti-ulcerogenic, and anti-inflammatory agent in traditional Oriental medicine. Cancer is a concept to be characterized by differentiating features, uncontrolled proliferation of cells, invasion of abnormal cells into healthy cells, and their spread through the bloodstream to vital organs. The key programmed cell death mechanism for silently killing unwanted and detrimental cells during embryonic development, tissue homeostasis, and immune regulation is apoptosis. Our research investigated the activation of apoptosis by the methanolic extract of R. mucronata and the expression of apoptotic and anti-apoptotic proteins. The cell cycle and apoptosis were observed by the Annexin V/PI-flow cytometry technique. The MTT test showed a strong cytotoxic effect on the cell lines of MCF-7. In MCF-7 cells, the sample demonstrated successful cell cycle arrest. More number of MCF7 cells get arrested in Sub G0/G1. In our study, FITC Rabbit Anti-Active Caspase 3 is used as a fluorochrome. It can be inferred from our study that good therapeutic potential against Human Breast derived diseases can be compared to the std control and the compound samples.