Senna petersiana (Bolle) leaf alkaloid-rich extracts exert cytotoxic and photodynamic activities in MCF-7 breast cancer cells

• Senna petersiana leaves alkaloid extracts showed anticancer effect against MCF-7 cancer cells. • The plant extracts in the presence of 405 nm laser light significantly elevated reactive oxygen species concentration in the breast tumour cells. • Alkaloid derived constituents from the plant alkaloid extracts inhibits key biomarkers linked with breast caner pathophysiology. Several findings have demonstrated the anticancer efficacies of plant-derived alkaloids' in different cancer types. This investigation determined the antiproliferative effects of alkaloid-rich extract from Senna petersiana leaves alone and in combination with laser light on MCF-7 breast cancer cells. Ethyl acetate and chloroform alkaloid extracts were obtained from the plant leaves via established protocol. The UV–visible spectrum of the extracts was compared at a scan range of 200 – 800 nm in a spectrophotometer. After treating MCF-7 cells with 240 μg/mL of each extract for 6 h, they were exposed to laser light at 405 nm before the viability, lactate dehydrogenase (LDH) activity, adenosine triphosphate (ATP) and reactive oxygen species (ROS) concentrations in cells of the various experimental groups where evaluated. Moreover, alkaloid-derived compounds annotated from the extracts were subjected to molecular docking analysis with proteins linked with breast cancer pathophysiology. Two peaks for the separate extracts at around 300 nm and 400 nm were observed, though the alkaloid chloroform extract presented an additional peak at the 600 nm range. Treatment with laser light after 6 h exposure to the plant extracts significantly decreased cell viability and ATP concentration but increased ROS levels and LDH release in the extract-laser light combined treatment compared to the extract-only and control group. 1,3,6,8-tetratert‑butyl‑9H-carbazole, 3-ethyl-4-methyl-1H-pyrrole-2,5‑dione and 3-bis(1-methylallyl) pyrrolidine alkaloid derivatives annotated from the S. petersiana showed strong hydrophobic bonds' mediated inhibition of cancer biomarkers. Despite demonstrating the anticancer potential of this plant's alkaloid fractions, further research to determine its phytoconstituents responsible for these photodynamic activities is needed.