Synergetic Comparative Study: Synthesis, Characterization, and Biological Investigations of Biosynthesized Zinc Oxide Nanoparticles of Aloe Barbadensis Miller, Citrus Lemon, and Ficus Carica Leaf Extracts

Microbial resistance is an emerging issue and nano-sized materials have been introduced as a promising solution for this type of resistance. Zinc oxide nano-scale particles (ZnONPs) are good agents for antimicrobial and antioxidant activity. Among all types of synthetic methods, plant-based ZnO nanoparticles have been reported as low cost, safe to perform, and environment friendly. In this research work, extracts of different plants are used to synthesize ZnO nanoparticles from zinc sulfate heptahydrate solution. In the study, extracts of plants including aloe vera, lemon, and fig were auspiciously used to synthesize ZnO nanoparticles. Different techniques were used for the analysis of the synthesized ZnO nanoparticles. ZnO nanoparticles produced by using Aloe barbadensis Miller, Citrus lemon, and Ficus carica leaf extract were investigated through ultraviolet-visible (UV/Vis), Fourier-transform infrared (FT-IR) spectroscopy and fluorescence spectrophotometry. Similarly, for antimicrobial activity disc diffusion method was adopted. The presence of the phytochemicals that behave as capping agents surrounding ZnO nanoparticles was proven by Fourier-transform infrared spectroscopy. The ZnO nanoparticles, at a concentration of 50 μg/mL, showed potent antimicrobial activity against Micrococcus luteus and Bacillus halodurans, and ZnO nanoparticle's antifungal activity was determined against two fungal strains Aspergillus niger and Aspergillus flavus. The results revealed that the antimicrobial agent, ZnO nanoparticles, can be synthesized using different plant extracts.