In vitro Investigation of Antimicrobial and Antioxidant Properties of Green Silver Nanoparticles Synthesized Using Ephedra gerardiana Plant Extract.

Background: The increasing prevalence of antibiotic-resistant bacteria necessitates exploring nanotechnology as a potential solution for microbial elimination.

Objectives: This study aimed to investigate the antimicrobial and antioxidant effects of silver nanoparticles synthesized using aqueous extract from the Ephedra gerardiana (E. gerardiana) plant (EG@AgNPs).

Methods: Optimal synthesis conditions, including silver nitrate concentration, time, and temperature, were determined. Characterization of EG@AgNPs was conducted, which was followed by antimicrobial assessment against eight bacterial strains and one fungal strain. Additionally, the antioxidant properties of EG@AgNPs were evaluated using the DPPH method.

Results: XRD analysis confirmed EG@AgNPs synthesis. DLS analysis revealed a hydrodynamic diameter of 22 nm. FT-IR analysis confirmed the presence of functional groups from the E. gerardiana plant extract in EG@AgNPs. FESEM and TEM images depicted spherical nanoparticles ranging in size from 10 to 20 nm. Antimicrobial investigations using the broth microdilution method demonstrated that E. gerardiana plant extract at 7.5 mg/ml inhibited only Streptococcus mutans and Candida albicans growth, with no antimicrobial effects observed at lower concentrations. However, EG@AgNPs significantly enhanced the antimicrobial properties of the E. gerardiana plant extract. Notably, these nanoparticles exhibited the most significant effect on E. coli and the least on S. salivaris, with MIC value of 125 and 2000 μg/ml, respectively. Furthermore, they inhibited C. albicans growth at a concentration of 62.5 μg/ml. An assessment of the antioxidant properties of EG@AgNPs indicated a significant increase in antioxidant activity.

Conclusion: The E. gerardiana plant extract has emerged as a promising option for silver nanoparticle synthesis. These nanoparticles have been found to exhibit potent antimicrobial properties against Gram-positive and Gram-negative bacterial species, as well as C. albicans. Additionally, they have demonstrated antioxidant properties.