Unlocking the bioactive potential of Lawsonia inermis: Eco-friendly silver nanoparticles with dual antimicrobial and anticancer efficacy

Silver nanoparticles synthesized through plant-mediated routes offer a promising interface between green chemistry and biomedical nanotechnology. In the present study, Lawsonia inermis aqueous leaf extract (LIALE) was used to fabricate silver nanoparticles (L-AgNPs) under mild processing conditions intended to minimize degradation of bioactive phytoconstituents. Successful nanoparticle formation was confirmed by a characteristic UV-Vis surface plasmon resonance peak at 418 nm and transmission electron microscopy showing an average metallic core diameter of ~17 nm. Dynamic light scattering revealed a hydrodynamic size of ~63 nm, consistent with a hydrated organic corona, while the zeta potential was −12 mV. Biologically, L-AgNPs displayed marked antibacterial activity against Escherichia coli , Staphylococcus aureus , Bacillus subtilis , and Streptococcus pyogenes , with MIC50 values of 4.9, 7.28, 5.9, and 8.35 μg/mL, respectively. The nanoparticles also showed improved antioxidant performance compared with crude extract in both DPPH and FRAP assays. In A549 lung adenocarcinoma cells, L-AgNPs exhibited potent antiproliferative activity (IC50 = 9.2 ± 0.45 μg/mL; 95% CI, 8.3–10.1 μg/mL), while no significant cytotoxicity was observed in HaCaT cells within the tested range (IC50 > 100 μg/mL), indicating a selectivity index of >10.87. Elevated intracellular ROS and apoptotic nuclear morphology further supported ROS-associated apoptotic injury in A549 cells. Together, these findings identify L-AgNPs as promising candidates for further investigation as multifunctional in vitro antibacterial and anticancer nanomaterials.