Cytotoxic and Apoptotic properties of the Flavonoid-rich Ethyl Acetate fraction of the Crude Methanol Leaf Extract of Syzygium samarangense (Blume) Merr. (Myrtaceae) against MCF-7 Breast Cancer Cells

ABSTRACT

Introduction@#Breast cancer is the most common cancer among women in the Philippines and about 3 in every 100 Filipina will be diagnosed with breast cancer in their lifetime. There is a need to discover safe, yet inexpensive herbal extracts with potential cytotoxic properties as potential treatment modalities to treat breast cancer. @*Objectives@#This study seeks to explore the cytotoxic and apoptotic properties of the ethyl acetate fraction of the defatted crude methanol leaf extract of Syzygium samarangense in MCF-7 breast cancer cell lines. @*Methods@#Screening for flavonoids of the extracts was performed using TLC, total flavonoids, total phenols, FTIR and LC-MS spectroscopy. The hydrogen peroxide and ferric reducing anti-oxidant power were used as substrates to assess in vitro anti-oxidative properties of the extracts. The MTT dye viability assay was used to assess the cytotoxic properties of the extracts against MCF-7 cells. Apoptotic properties of the extracts in MCF-7 cells were determined by caspase-3 activation assay, DNA fragmentation patterns and fluorescence microscopy after annexin-V and propidium iodide staining. @*Results@#The abundance of flavonoids in the ethyl acetate fraction of the crude methanol leaf extract was established by TLC, FTIR, LC-MS/MS, total flavonoid and total phenol analyses. The in vitro anti-oxidative properties of this extract was comparable to ascorbic acid. The median inhibitory concentration (IC50) of this extract in MCF-7 breast cancer cell lines was 7.2 mcg/mL while doxorubicin registered an IC50 of 1.2 mcg/mL. At this concentration, the extract was not cytotoxic to normally-dividing breast epithelial cells. Cytotoxicity of the extract was mediated via apoptosis as demonstrated by DNA fragmentation, caspase-3 activation and fluorescence microscopic analyses. @*Conclusion@#The study shows that the flavonoid-rich ethyl acetate fraction of the crude methanol leaf extract of S. samarangense possesses potent apoptotic and cytotoxic properties against MCF-7 breast cancer cell lines at low concentrations.