Green synthesis of silver nanoparticles using Sonchus asper flower extract with enhanced in vitro/in vivo biomedical and photocatalytic activities

Green nanotechnology offers an eco-friendly and cost-effective strategy for synthesizing multifunctional nanomaterials with diverse biomedical and environmental applications. In this study, silver nanoparticles (SA-AgNPs) were biosynthesized using S. asper flower extract and comprehensively characterized by UV-Vis spectroscopy, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX) analyses. UV-Vis spectroscopy confirmed SA-AgNPs formation with a characteristic surface plasmon resonance peak at 418 nm. FT-IR analysis identified phytochemical functional groups responsible for the reduction and stabilization of the nanoparticles; XRD confirmed their crystalline nature, and SEM revealed uniformly distributed, nearly spherical particles; the particle size ranged from 10 to 180 nm, with a mean particle size of 19.7 nm. The synthesized SA-AgNPs exhibited strong antioxidant activity, achieving 77.88 ± 2.1% DPPH radical scavenging at 100 µg/mL. They also demonstrated broad-spectrum antibacterial activity against Gram-positive and Gram-negative bacteria. In vitro anti-inflammatory activity showed 66.73 ± 2.5% inhibition of protein denaturation at 100 µg/mL, while in vivo studies using a xylene-induced ear edema model showed inhibition of 55.04%, 68.52%, and 85.10% at 4, 12, and 24 h, respectively, following treatment with 90 mg/kg of SA-AgNPs. In vitro antidiabetic assays revealed concentration-dependent inhibition of α-amylase and α-glucosidase, with maximum inhibition values of 74.94 ± 1.5% and 80.14 ± 0.65%, respectively, at 100 µg/mL. In alloxan-induced diabetic mice, 30 days of SA-AgNPs treatment significantly reduced blood glucose levels and improved pancreatic and liver function, as confirmed by biochemical and histopathological analyses. In addition, SA-AgNPs exhibited excellent photocatalytic activity, achieving 84.76% degradation of MB under UV irradiation after 90 min and following pseudo-first-order kinetics. Overall, the biosynthesized SA-AgNPs possess significant antioxidant, antibacterial, anti-inflammatory, antidiabetic, and photocatalytic properties, highlighting their potential for biomedical and environmental applications.