Green synthesis of gold and silver nanoparticles using crude extract of Aconitum violaceum and evaluation of their antibacterial, antioxidant and photocatalytic activities

Abstract

Green synthesis of metal nanoparticles (NPs) has received extensive attention over other conventional approaches due to their non-toxic nature and more biocompatibility. Herein we report gold and silver NPs (AuNPs@AV and AgNPs@AV) prepared by employing a green approach using crude extract of Aconitum violaceum Jacquem. ex Stapf. The synthesized NPs were characterized using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Energy Dispersive X-ray (EDX), X-ray Diffraction (XRD), UV/Visible spectroscopy, Fourier Transform Infrared (FTIR), X-ray Photoelectron Spectroscopy (XPS), and Zeta Potential. Morphological analysis showed spherical and triangular shapes of the NPs with average size of <100 nm. The AuNPs@AV and AgNPs@AV exhibited effective antibacterial activities, with minimum inhibitory concentrations (MICs) of 95 and 70 μg/mL against Lactobacillus acidophilus (L. acidophilus) and 90 and 65 μg/mL against Escherichia coli (E. coli), respectively. Strong antioxidant effect of AuNPs@AV and AgNPs@AV were reported against DPPH radical and PTIO within range of IC50 values; 161–80 μg/ml as compared to the standard (23–11 μg/mL) respectively. Moreover, the AuNPs@AV and AgNPs@AV showed efficient photocatalytic activity and degraded 89.88% and 93.7% methylene blue (MB) dye under UV light, respectively.

Assessing the Potential of Aconitum Laeve Extract for Biogenic Silver and Gold Nanoparticle Synthesis and Their Biological and Catalytic Applications

“…The process outlined in our previous study was followed in the green synthesis of AgNPs [ 88 , 89 ]. In a 100 mL beaker, 5 mL of AgNO 3 salt solution (0.002 M) in deionized water (DW) was introduced and stirred continuously for 5 min.…”

“…The green synthesis of AuNPs was carried out using a modified procedure from the literature [ 88 , 89 ]. In a standard experimental setup, 5 mL of the crude extract containing 20 mg/mL was added to a 2 mM HAuCl 4 – solution (5 mL) in a beaker, and the mixture was stirred for 40 min at room temperature.…”

“…The PTIO assay was carried out in accordance with the previously described method, with minor adjustments [ 88 , 91 ]. From each concentration (12.5, 25, 50, 100, and 200 µg/mL) of the NPs@AL and plant extract, aliquots of 200 µL were taken and combined with 800 µL of the PTIO solution (1 mM), followed by a thorough mixing.…”

“…The ABTS radical scavenging activity of the NPs@AL and the crude extract was evaluated in a dose-dependent manner using the previously described method with some changes [ 88 , 92 ]. Accordingly, ABTS (7 mM) and potassium persulfate (2.45 mM) were combined in ethanol in order to produce an ABTS stock solution.…”