Characterization and evaluation of the antibacterial activities of silver nanoparticle synthesized with Plantago lanceolata seed extract

Abstract

Background and Aims: The increase in the incidence of antimicrobial resistance in pathogens has led researchers to identify new and effective antimicrobial agents. Green production of nanoparticles has received attention due to its compatibility with the environment and low cost. The present study sought to characterize and evaluate the antibacterial activities of silver nanoparticles synthesized with Plantago lanceolata seed extract. Materials and Methods: In this study, after the synthesis of silver nanoparticles by chemical and green methods, the characteristics of silver nanoparticles synthesized with the P. lanceolata seed extract were evaluated by UV-Vis, DLS, XRD, FT-IR, and TEM methods. Thereafter, the optimal conditions for the synthesis of nanoparticles and the antibacterial activity of the P. lanceolata extract, chemical silver nanoparticles, and green silver nanoparticles against standard bacterial strains were investigated by determining the minimum inhibitory concentration (MIC) using the broth microdilution method. Results: Based on the absorption spectrum of green silver nanoparticles with UV-Vis, the optimal concentration of silver nitrate was 20 mM, the suitable synthesis temperature was 57 °C, and the best reaction time was reported as 30 sec. The results of XRD, FT-IR, and TEM analyses confirmed the synthesis of green silver nanoparticles with oval and spherical morphology with a size of 20-40 nm. The P. lanceolata extract and chemical silver nanoparticles had no significant antibacterial effect. Nonetheless, green silver nanoparticles had significant antibacterial activity on the studied bacteria, with the highest antibacterial effect against Staphylococcus aureus and Enterococcus faecalis (MIC=125 μg/mL). Conclusion: As evidenced by the obtained results, P. lanceolata seed extract significantly increased the antibacterial activity of silver nanoparticles. This research demonstrated the potential of environmentally friendly silver nanoparticles synthesized in the presence of P. lanceolata extract with significant antibacterial effects for various biomedical applications.