Cancer is one of the most dangerous threats to human health and possibly the utmost task for current medicine. Currently, bio-based synthesis of nanoparticles from plants has gained much interest due to its potential medicinal applications. In the present study, a biological approach was employed for biogenic (green) synthesis of silver nanoparticles (AgNPs) using dried leaf extract of Asian spider flower (Asf). The biogenic synthesis of Asf-AgNPs (Asian spider flower-Silver nanoparticles) was established using ultra violet-visible (UV-vis) spectra which exhibited a wide superficial plasmon resonance of AgNPs at 445 nm. These nanoparticles clearly showed the formation of poly-disperse crystalline solids (spherical shape) with particle size range of <50 nm based on observation under a transmission electron microscope (TEM). Infrared spectroscopy (FTIR) revealed carboxylic acids (C = O stretch) known to act as a capping agent and a reductant in plant extracts. Elemental silver signal peak was observed in the graph obtained from energy-dispersive X-ray (EDX) analysis. Biocompatibility tests for Asf-AgNPs at different doses were evaluated against human breast cancer cells (MCF7) for cell viability and apoptotic analysis. According to the evaluation, biosynthesized Asf-AgNPs could prevent the explosion of human breast tumor cells (MCF7) in IC50 at a dose of 40 μg/mL after 48 h of treatment. The results obtained in the IC50 dosage treatments were statistically significant (p < 0.05) when compared with control. Nuclear damage of cells was further investigated using annexin V-FITC/PI dual staining and DAPI (4′,6-diamidino-2-phenylindole) staining method. Bright blue fluorescence with condensed and fragmented chromatin was observed. Western blot analysis showed increased expression levels of caspases-3 and 9 (apoptotic proteins). These results indicate that bio-approached AgNPs synthesized through Asf plant extract could be used as potential therapeutic medications for human cancer cells.