Synthesis and Characterization of Gold Nanoparticles (AuNPs) from Chrozophora rottleri (Geiseler) Spreng. An Evaluation of Antioxidant and Antimicrobial Activities
Authors:   Department of Botany, University College of Science, Osmania University, Hyderabad, Telangana, -500 007 India, Hymavathi K. , Sabitha Rani A. ,   Department of Botany, University College of Science, Osmania University, Hyderabad, Telangana, -500 007 India
Published: November 2024

This is the first report of its kind on the study. Applications for nanobiotechnology include coatings, cosmetics, packaging, biomedicine, and boosting biological activity. Given the importance of Chrozophora rottleri (Euphorbiaceae) we developed gold nanoparticles (AuNPs) economically and ecologically responsibly. In less than a minute, the color of the gold nanoparticles (AuNPs) synthesized in this work changed from yellow to wine red. Advanced methods such as UV-visible spectroscopy, Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and zeta potential (ZP) were used to study these nanoparticles. The synthesized gold nanoparticles’ anti-microbial (bacterial and fungal) and in vitro antioxidant (DPPH and H2O2) characteristics were evaluated. Standard ascorbic acid concentrations of 10, 25, 50, 75, and 100 µg/ml were used to investigate the DPPH free radical scavenging activity. The findings showed that 18.53±0.162 was the lowest percentage of inhibition and 83.62±0.785 was the greatest. Analogously, the ascorbic acid hydrogen peroxide radical scavenging (H2O2) assay revealed that the maximum % inhibition was 87.27±0.467 and the lowest was 19.52±0.225. The Agar well-diffusion method was used to examine the antibacterial effectiveness of ampicillin and synthesized gold nanoparticles (AuNPs). Four distinct concentrations (25, 50, 75, and 100 µl) were assessed in relation to several bacterial pathogens, such as Escherichia coli, Streptococcus pneumoniae, Pseudomonas aeruginosa, and Staphylococcus aureus. Elevated doses of traditional Ampicillin demonstrated a progressive degree of inhibitory impact on E. coli and S. aureus, signifying heightened antimicrobial efficacy. Zones measuring 16 mm, 20 mm, 22 mm, and 25 mm were seen in ampicillin, while zones measuring 11 mm, 13 mm, 14 mm, and 16 mm were seen in E. coli The synthesized gold nanoparticles (CR-AuNPs) demonstrated increased zones of inhibition measuring 1.2 mm, 12 mm, 14 mm, and 17 mm, indicating greater antibacterial activity against S. pneumoniae. Similar to this, P. aeruginosa was inhibited by AuNPs, and the zones of inhibition measured 0.6 mm, 12 mm, 16 mm, and 18 mm. The CR-AuNPs show activity against S. aureus, E. coli, S. pneumoniae, and P. aeruginosa at a concentration of 200 µg/ml, which is the minimum inhibitory concentration (5, 10, 25, 50, 100, and 200 µg/ml). The well diffusion method was utilized to evaluate the antifungal efficacy of AuNPs and Fluconazole against Aspergillus niger. The findings showed that the zones of inhibition, which measured 12 mm, 16 mm, 21 mm, and 25 mm, gradually increased. Moreover, the zones of inhibition against Candida albicans were observed to be 13 mm, 16 mm, 18 mm, and 22 mm. At 12 mm, 15 mm, 19 mm, and 23 mm, the CR-AuNPs showed increasingly wider zones of inhibition against Aspergillus niger. Furthermore, 11 mm, 14 mm, 17 mm, and 19 mm zones of inhibition were seen in Candida albicans. The findings point to the potential for producing gold nanoparticles (AuNPs) using green synthesis methods that are both economical and ecologically benign. Moreover, this work is the first to suggest that C. rottleri may have antioxidant and antibacterial properties. As a result, this creates new chances in various fields in addition to medicines