Biosynthesis of Silver Nanoparticles from Duchesnea indica Extracts Using Different Solvents and Their Antibacterial Activity

Silver nanoparticles (AgNPs) were synthesized using the whole plant of Duchesnea indica (DI) which was extracted in different solvents; the antimicrobial effects of the extract were investigated in this study. The extraction of DI was performed using three different solvents: water, pure ethanol (EtOH), and pure dimethyl sulfoxide (DMSO). AgNP formation was monitored by measuring the UV–Vis spectrum of each reaction solution. After synthesis for 48 h, the AgNPs were collected and the negative surface charge and size distribution of the synthesized AgNPs were measured using dynamic light scattering (DLS). The AgNP structure was determined by high-resolution powder X-ray diffraction (XRD) and the AgNP morphology was investigated using transmission electron microscopy (TEM). AgNP antibacterial activities were evaluated against Bacillus cereus, Staphylococcus aureus, Escherichia coli, Salmonella enteritidis, and Pseudomonas aeruginosa using the disc diffusion method. Additionally, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values were also determined. Biosynthesized AgNPs showed enhanced antibacterial activity against B. cereus, S. aureus, E. coli, S. enteritidis, and P. aeruginosa compared with that of pristine solvent extract. These results suggest that AgNPs synthesized from extracts of DI are promising antibacterial agents against pathogenic bacteria and can be further applied in the food industry.