Anti-proliferative and photodynamic activities of Senna didymobotrya (Fresen.) leaf alkaloid-rich extracts against breast cancer cells

Background: Amongst all neoplastic diseases, breast cancer represents a major cause of death among the female population in developed and developing countries. Since alkaloid drugs are commonly used in chemotherapy to manage this disease, this study investigated the anti-proliferative effectiveness of alkaloid-rich fractions of Senna didymobotrya leaves only and with laser irradiation against MCF-7 breast cancer cells. Method and materials: A powdered sample of the plant leaves was extracted with 50% ethanol, filtered and their pH was adjusted with acid and base solution followed by partitioning with chloroform and ethyl acetate solvents. Cells were treated with 240 μg/mL of the respective extracts, while those in the photodynamic therapy groups, cells were exposed to laser (405 nm wavelength and 10 Jcm⁻²) irradiation 6 h post extracts' administration. Results: Treatment with the S. didymobotrya leaves alkaloid extracts significantly decreased the ATP concentration and overall viability of the MCF-7 cells. Reactive oxygen species (ROS) levels in cell groups treated with the extracts and laser light were considerably higher than in experimental groups treated with only the extracts. Moreover, the molecular docking analysis revealed the involvement of only hydrophobic bonds in the interactions of the plant’s alkaloid-derived phytoconstituents’ with selected cancer protein biomarkers. Conclusion: Although the in silico analysis suggests that the plant-identified alkaloid phytoconstituents inhibition of estrogen receptor-alpha, human epidermal growth factor receptor-2 and progesterone receptor proteins involved in breast cancer pathogenesis could explain a possible mechanism for the observed anticancer effect, more detailed in vitro molecular experiments are necessary to confirm these findings.