Green Synthesis of Silver Nanoparticles Using Astragalus tribuloides Delile. Root Extract: Characterization, Antioxidant, Antibacterial, and Anti-Inflammatory Activities

Abstract

Today, the green synthesis of metal nanoparticles is a promising strategy in material science and nanotechnology. In this research, silver nanoparticles (AgNPs) were synthesized through the high-efficient, cost-effective green and facile process, using the <i>Astragalus tribuloides</i> Delile. root extract as a bioreduction and capping agent at room temperature. UV-Vis spectroscopy was applied for the investigation of the reaction proceedings. To characterize the greenly synthesized AgNPs, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction spectroscopy (XRD), and transmission electron microscopy (TEM) analyses were utilized. In addition, the total phenolics and flavonoids contents, antioxidant, antibacterial, and anti-inflammatory activities of the greenly synthesized AgNPs and the <i>A. tribuloides</i> root extract were evaluated. The results indicated that the AgNPs had spherical morphology and crystalline structure with the average size of 34.2 ± 8.0 nm. The total phenolics and flavonoids contents of the greenly synthesized AgNPs were lower than those for the <i>A. tribuloides</i> root extract. The resultant AgNPs exhibited the appropriate antioxidant activity (64%) as compared to that for the <i>A. tribuloides</i> root extract (47%). The antibacterial test approved the higher bactericidal activity of the resulting AgNPs on the Gram-positive and Gram-negative bacteria in comparison to the <i>A. tribuloides</i> root extract. Considering the anti-inflammatory activity, the greenly synthesized AgNPs showed a stranger effect than the <i>A. tribuloides</i> root extract (82% versus 69% at 500 μg/mL). Generally, the AgNPs that were fabricated by using the <i>A. tribuloides</i> root extract had appropriate antioxidant, antibacterial, and anti-inflammatory activities and, therefore, can be considered as a promising candidate for various biomedical applications.