In this study, we report one-pot, single step synthesis of silver nanoparticles stabilized by using arbutin. The concentration of reducing agent (NaBH₄) used in the preparation was kept at double, and arbutin was used as a stabilizing agent. The confirmation of prepared silver nanoparticles was done by color change and UV-Vis surface plasmon resonance peak at 435 nm in UV-Vis spectrum. Size dispersion of nanoparticles was carried out by Dynamic Light Scattering (DLS) and surface charge on nanoparticles. Stability was analyzed by Zeta potential. A strong negative charge indicated that nanoparticles are well stabilized throughout the solution. Morphology and 3D topographic images were obtained by Atomic Force Microscopy (AFM). The crystalline nature of nanoparticles was elucidated by X-ray diffraction analysis. The size and morphology of solid, well-grinded nanoparticles was proceeded by Scanning Electron Microscopy (SEM). The catalytic activities of nanoparticles were carried out against methylene blue, methyl orange, safranin, and eosin. The results demonstrated that synthesized silver nanoparticles commenced the degradation reaction of dyes mentioned. Prepared silver nanoparticles are found to have adequate catalytic activity, as it can be comprehended in time-dependent UV-Vis spectrums of dyes after treating them with AgNPs.

The severe acute respiratory syndrome coronavirus 2, also known as SARS-CoV-2, is the causative agent of the COVID-19 global pandemic. SARS-CoV-2 has a highly conserved non-structural protein 12 (NSP-12) involved in RNA-dependent RNA polymerase (RdRp) activity. For the identification of potential inhibitors for NSP-12, computational approaches such as the identification of homologous proteins that have been previously targeted by FDA-approved antivirals can be employed. Herein, homologous proteins of NSP-12 were retrieved from Protein DataBank (PDB) and the evolutionary conserved sequence and structure similarity of the active site of the RdRp domain of NSP-12 was characterized. The identified homologous structures of NSP-12 belonged to four viral families: Coronaviridae, Flaviviridae, Picornaviridae, and Caliciviridae, and shared evolutionary conserved relationships. The multiple sequences and structural alignment of homologous structures showed highly conserved amino acid residues that were located at the active site of the RdRp domain of NSP-12. The conserved active site of the RdRp domain of NSP-12 was evaluated for binding affinity with the FDA-approved antivirals, i.e., Sofosbuvir and Dasabuvir in a molecular docking study. The molecular docking of Sofosbuvir and Dasabuvir with the active site that contains conserved motifs (motif A-G) of the RdRp domain of NSP-12 revealed significant binding affinity. Furthermore, MD simulation also inferred the potency of Sofosbuvir and Dasabuvir. In conclusion, targeting the active site of the RdRp domain of NSP-12 with Dasabuvir and Sofosbuvir might reduce viral replication and pathogenicity and could be further studied for the treatment of SARS-CoV-2.