Multifunctional silver nanoparticles synthesized by Streptomyces rochei CS-1: postharvest efficacy and biomedical activities

Silver nanoparticles (AgNPs) synthesized through biological routes are increasingly explored for sustainable agricultural and biomedical applications. In the present study, Streptomyces rochei CS-1, isolated from the rhizosphere of Gymnema sylvestre R. Br., was employed for the green synthesis of silver nanoparticles (CS-1-AgNPs). The formation of CS-1-AgNPs was confirmed by UV-Vis spectroscopy, FTIR, TEM, EDX, XRD, TGA, DLS and zeta potential analyses, revealing stable, polydisperse nanoparticles with sizes ranging from 14 to 72 nm and a negative surface charge (-40.0 mV). CS-1-AgNPs exhibited significant antifungal activity against Alternaria solani and Fusarium oxysporum, achieving up to 69.11 ± 1.21% and 78.22 ± 1.43% mycelial inhibition, respectively, at 100 μg/mL. Broad-spectrum antibacterial activity was observed against both Gram-positive and Gram-negative pathogens. In vitro biomedical evaluation demonstrated dose-dependent inhibition of α-amylase and α-glucosidase, enhanced glucose uptake, moderate anti-inflammatory activity in HRBC membrane stabilization and protein denaturation assays, and antiproliferative activity against human glioblastoma (U-87MG) cells with an IC50 value of 160.17 μg/mL, accompanied by apoptosis induction. Collectively, these findings highlight the multifunctional in vitro bioactivity of CS-1-AgNPs, suggesting their potential relevance in postharvest disease management and biomedical research. Further in vivo validation, biosafety assessment, and formulation studies are required prior to translational or agricultural application.