Green synthesis, characterization and antimicrobial evaluation of silver nanoparticle composites from Aloe barbadensis miller and Cymbopogon citratus

Abstract

The rising threat of antimicrobial resistance in animal health necessitates the development of effective and sustainable alternatives to conventional antibiotics. The present study was taken up to explore the synergistic antibacterial potential of composite silver nanoparticles synthesized using Aloe barbadensis miller and Cymbopogon citratus. Phytochemical analysis was performed using the aqueous extracts of the selected plants. Silver nanoparticles (AgNPs) were synthesized from the respective plant extracts and different composites ratios of synthesized nanoparticles were prepared and characterized by UV–Vis spectrophotometry, scanning electron microscopy (SEM), dynamic light scattering (DLS) and inverted microscopy. Minimum inhibitory concentration (MIC) and antimicrobial efficacy of the test compounds was evaluated against common field isolates of Staphylococcus aureus, Klebsiella pneumoniae and Escherichia coli. Phytochemical analysis revealed bioactive compounds saponins, tannins, phenols, flavonoids, proteins, glycosides and essential oils. Visible observation of color changes and UV–visible spectra exhibited plasmon peaks at 409 nm and 410 nm for individual plant AgNPs and composite at 418 nm. SEM showed spherical AgNPs with uniform distribution. DLS revealed average size of 50 nm. Inverted microscopy showed concentric ring structures. MIC showed appreciable inhibition and ABST using disk diffusion (Bauer-Kirby) revealed substantial zones of inhibition against above bacterial isolates. These findings suggest composite green nanoparticles could be a promising alternative for combating bacterial infections in animals upon confirming its efficacy on different clinical cases.