A. Hassanvand - Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Islamic Republic of Iran.
S. Saadatmand - Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Islamic Republic of Iran.
H. Lari Yazdi - Department of Biology, Borujerd Branch, Islamic Azad University, Borujerd, Islamic Republic of Iran
A. R. Iranbakhsh - Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Islamic Republic of Iran.

Silver Nanoparticles (AgNPs) are widely used in medical and pharmaceutical applications due to their antimicrobial properties. In this study, Ag-NPs were synthesized using Viola tricolor aqueous extract as a reducing and capping agent. The presence of synthesized Ag-NPs was first confirmed with UV-Visible, SEM, TEM, XRD, and FTIR analyses, and then their antimicrobial characteristics were studied based on the Minimum Inhibitory Concentration (MIC). The SEM analysis showed that the synthesized AgNPs were spherical in shape. The particle size histogram revealed that the average particle size of the AgNPs was ۴۹.۴۵ nm. Findings from the FTIR and UV-Vis spectra showed the successful formation of Ag-NPs because the functional groups involved in the synthesis process and adsorption peaks were well developed. Furthermore, the Ag-NPs had a peak absorption at ۴۲۰ nm in the spectrometry. MIC results showed the strong antimicrobial effects of the synthesized Ag-NPs. Results of the Minimum Bactericidal Concentration (MBC) revealed the dose-dependent cytotoxicity of the Ag-NPs. Nanoparticles could exert the inhibitory effect of DDPH free radicals in a dose-dependent manner. Methyl tetrazolium (MTT) results showed that silver nanoparticles had a dose-dependent cytotoxic effect and significantly reduced cell survival. The IC۵۰ values for Ag-NPs and the extract were ۱۱.۸۳ and ۲۰۴.۴ μg mL-۱, respectively. This study showed a higher cytotoxic effect of the green synthesized nanoparticles on hepatocellular carcinoma cells than the extract. Consequently, the biosynthesis of Ag-NPs using aqueous extract of V. tricolor is clean, inexpensive, and has antibacterial, anticancer and antioxidant activities. Hence, it can be used as a drug candidate.

Antimicrobial characteristics, Cytotoxicity, Minimum bactericidal concentration Minimum inhibitory concentration.