Biosynthesis, Characterization, and Antimicrobial Assessment of Metal Nanoparticles from Dryopteris manniana (HOOK.) C. Chr Leaf Extract

Abstract

Background: An integral part of nature is medicinal plants containing natural constituents which are vital to health. Dryopteris manniana (Hook.) C. Chr. leaves contain phytochemicals such as polyphenols and flavonoids which serve as an effective reducing agent. Methods: Metallic nanoparticles were synthesized by reducing salts of silver, nickel, manganese, and copper using Dryopteris manniana leaf extracts to form metal nanoparticles represented as AgNPs, NiNPs, MnNPs, and CuNPs respectively. The obtained nanoparticles were then characterized using UV-Visible Spectroscopy, Fourier-transform infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Energy-dispersive X-ray spectroscopy (EDX). The antimicrobial activities of the nanoparticles were investigated against six microbial strains using the disk diffusion method. Results: The EDX result identified the metal atoms present in the metal nanoparticles formed. The SEM revealed that AgNPs have a diamond-like crystalline, CuNPs have a triangular-like structure, NiNPs have a teardrop-like structure, and MnNPs have a spherical crystalline structure. The results of the antimicrobial experiments showed that the nanoparticles have activity against all the tested bacteria but are less active against some isolated fungi. AgNPs showed zone of inhibitions: S. aureus (10 mm), α-H. streptococcus (8 mm), and E. coli (12 mm), while CuNPs exhibited 9 mm, 11 mm, and 11 mm against S. aureus, E. coli, and α-H. streptococcus respectively. Conclusion: This method for green metal nanoparticle synthesis may useful in nanomedicine, environmental, and industrial applications as they possess greater effectiveness and reduced toxicity, however, further investigation will be implemented.