Comparative Evaluation of Anticancer Efficacy and Molecular Mechanism of Silver Nanoparticles Synthesized from Methanolic and Ethanolic Extracts of Citrus medica

The development of biosynthesized and cost-efficient nanomedicine is a promising strategy in cancer therapeutics. Herein, we have synthesized highly potent silver nanoparticles (AgNPs) using methanolic and ethanolic extracts of Citrus medica fruit, unraveling the significance of different solvents. Fourier transform Infrared spectroscopy confirmed the occurrence of secondary metabolites on the synthesized AgNPs’ surface. The Zetasizer analysis showed no significant particle-size differences between both solvents based-synthesized AgNPs; however, zeta potential showed significant differences in the particle surface charge. The high-resolution transmission electron microscopy confirmed a predominantly spherical morphology of AgNPs. Notably, AgNPs synthesized from ethanolic extracts exhibited smaller sizes (5-7 nm) and a more uniform distribution compared to their methanolic counterparts. The X-ray diffraction demonstrated a polycrystalline nature with a face-centered cubic structure. Functional assays showed a significant increase in the anticancer efficacy of ethanolic extract-derived AgNPs against the breast cancer cells (MCF-7 and MDA-MB-231), accompanied by extensive DNA fragmentation and enhanced induction of apoptosis. Mechanistically, both methanolic and ethanolic AgNPs induce upregulation of pro-apoptotic gene expression (e.g., TP53 , BAX , and CYCS ) and downregulation of anti-apoptotic gene (e.g., BCL2 ). The flow cytometry analysis showed a substantial increase of the ethanolic extract-based AgNPs in the late-stage apoptotic cells, which was further confirmed by morphological changes in treated MCF-7 cells. This study reveals the pivotal influence of the selection of solvent on the synthesis and anticancer potency of AgNPs, significantly impacting their ability to induce apoptosis in MCF-7 cells. Our findings introduce a novel strategy for optimizing green synthesized AgNPs-based therapies, offering promising avenues for advancing nanoparticle-driven cancer treatments and potentially transforming future therapeutic approaches in oncology.