Iranian Journal of Chemical Engineering (IJChE)

Abstract In this research, gold nanoparticles (AuNPs) were synthesized for the first time utilizing the extract of Teucrium polium. The study evaluated the antimicrobial potential of both methanolic and aqueous extracts of T. polium, alongside the synthesized AuNPs. Furthermore, the impact of varying AuNP concentrations on the phytochemical characteristics of the plant extract was analyzed. The successful fabrication of AuNPs was verified through a comprehensive suite of characterization techniques, including UV-Vis spectroscopy, XRD, TEM, SEM, and FTIR. Morphological analysis via SEM and TEM revealed spherical nanoparticles with a mean diameter of 22.89 nm, while the UV-Vis spectrum exhibited a characteristic surface plasmon resonance (SPR) peak at 420 nm. The reaction reached its optimum efficiency at pH 5. Antimicrobial assays indicated that the methanolic extract possessed superior antibacterial and antifungal properties compared to the aqueous version, yielding maximum inhibition zones for Escherichia coli (14±1.4 mm) and Aspergillus niger (15±0.7 mm). Additionally, the AuNPs demonstrated notable efficacy against gram-negative bacteria, with the highest inhibition observed for E. coli (18±0.7 mm) and A. niger (20±0.9 mm). Regarding the antioxidant capacity and reducing power (phenolic flavonoid content), a concentration-dependent increase was observed up to 60 ppm (IC50=9.94 µg/mL; reducing power= 16.85 mMFe2+/mg sample), followed by a decline at concentrations exceeding this threshold.

Abstract In contemporary society, a plethora of human industries are fundamentally dependent on the antibacterial capabilities of various nanoparticles, rendering their absence in contemporary applications nearly unimaginable. Silver nanoparticles (AgNPs) are widely used for their potent antibacterial properties in various applications, including medical and industrial settings. Controlling microbial growth is critical to prevent health and environmental issues. In this study, AgNPs is biosynthesized using the Celtis caucasica leaf extract, optimizing synthesis parameters to achieve high purity and uniform particle size. The ideal synthesis parameters involved combining 1.5 mL of plant leaf extract with 10 mL of a 3 mM AgNO3 solution, maintaining a pH of 7, and heating the mixture at 70 °C for 45 minutes.UV-Vis, FTIR, and TEM analyses verified the synthesis of nearly spherical AgNPs with a mean size of approximately 20 nm, displaying a typical SPR absorption peak at 425 nm. FTIR data revealed key bioactive groups in the extract that enabled Ag⁺ ion reduction. The AgNPs showed robust antibacterial effects against Staphylococcus aureus (MIC 12.5 µg/mL) and Escherichia coli (MIC 25 µg/mL).