Green Synthesis, Characterization, and Antimicrobial Activity of Phyllanthus amarus Silver Nanoparticles

Abstract

Background: The emergence of antibiotic-resistant microorganisms poses serious concerns to global health, demanding the discovery of novel therapeutic remedies.

Objectives: To investigate the potential of green synthesised silver nanoparticles from      Phyllanthus amarus as a novel treatment for combating microbial infections.

Methods: Phyllanthus amarus contains phyto-bioactive compounds such as phenols, alkaloids, and flavonoids, which act as effective reducing and capping agents for the green synthesis of silver nanoparticles, referred to as PA-AgNPs. The biosynthesised nanoparticles were characterised using Ultraviolet-visible (UV-Vis) spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), and Energy-dispersive X-ray (EDX) analysis. The antimicrobial activity of the nanoparticles was tested against six clinical isolates using the disk diffusion method.

Results: The UV-Vis spectra confirmed the synthesis of PA-AgNPs, with a characteristic absorption peak between 300 - 450 nm. The FTIR spectra indicated a strong interaction between the PA-AgNPs and the plant extract, showing a shift in peak location, reduction of peak intensity, or the formation of new peaks. SEM images showed mostly irregularly shaped and clustered nanoparticles with noticeable porosity. EDX analysis confirmed the presence of silver and elements from the plant extract. The PA-AgNPs displayed significant antimicrobial activity with inhibitory zones against K. pneumoniae (20 mm), E. coli (16 mm), S. aureus (8 mm), S. pneumoniae (4 mm), A. fumigatus (10 mm), but not against C. albicans.

Conclusion: This study successfully demonstrated the green synthesis of silver nanoparticles with promising antimicrobial properties, highlighting their potential for applications in biomedical and pharmaceutical fields.