Eco-friendly synthesis of silver nanoparticles: multifaceted antioxidant, antidiabetic, anticancer, and antimicrobial activities

Diabetes, cancer, and multidrug-resistant bacteria are major global health threats, driving the search for novel, safe, and affordable therapeutics. Here, silver nanoparticles (Ag-NPs) were biosynthesized using the aqueous extract of Rosmarinus officinalis L. via a sustainable, eco-friendly, and cost-effective green approach. Characterization by UV–Vis, FT-IR, EDX, XRD, TEM, SEM, TGA, DLS, and zeta potential confirmed the formation of well-dispersed, spherical, crystalline nanoparticles with an average size of 60.5 nm, uniform morphology, and high thermal stability. The Ag-NPs displayed concentration-dependent multifunctional activities. Antibacterial assays revealed strong effects against both standard and MDR strains, including Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumoniae (inhibition zones: 11.7–29.7 mm). Potent antioxidant activity was observed with an EC₅₀ of 7.81 µg mL⁻1, close to ascorbic acid (3.27 µg mL⁻1). Antidiabetic activity reached 85.5% (α-amylase) and 82.6% (α-glucosidase) inhibition at 1000 µg mL⁻1, comparable to acarbose (97.5% and 96.3%). Moreover, Ag-NPs showed selective cytotoxicity against MDA and PANC-1 cells (IC₅₀: 177.2 and 115.3 µg mL⁻1), with lower toxicity toward Vero and Wi38 normal cells (IC₅₀: 233 and 207 µg mL⁻1). These findings highlight the promise of R. officinalis–mediated Ag-NPs as multifunctional nanomaterials for biomedical applications.