Abstract: Bio-nano synthesis and its widespread applications have become essential for sustainable development and welfare of humanity. The present study reports a biosynthetic pathway to produce highly stable, bio-inspired silver Nanoparticles (AgNPs) using fresh Sterculia quadrifida leaves. Following the traditional approach, UV-visible spectroscopy confirmed the formation of AgNPs. AFM and TEM results revealed their size, morphology and crystalline nature. Moreover, FTIR analysis exposed the nature of biomolecules adhering to the surface of silver nanoparticles which increased their stability. Sterculia quadrifida extracts rendered excellent reducing capability. Consequently, this procedure proved to be simpler, eco-friendly, cost-effective, reproducible and compatible with medical and pharmaceutical applications as well as large-scale commercial production. The nanoparticles, thus, synthesized, exhibited effective antimicrobial activity and AgNPs together with phytochemicals resulted in a strong antiproliferative effect. As such MTT assay helped to determine the levels of cytotoxicity. Furthermore, the study of apoptosis elucidated the possibility of employing AgNPs for programmed cell death. Since, increased apoptosis is a characteristic feature of AIDS, Alzheimer’s and Parkinson’s disease and decreased apoptosis trigger lupus or cancer, AgNPs can induce apoptosis in such cancer or tumor cells.