Antimicrobial, Anticancer, and Antioxidant Activities of Zinc Oxide Nanoparticles Synthesized Using Ethyl Acetate Extract of <i>Ageratum houstonianum</i> Mill. Leaf

Abstract In the era of increasing antimicrobial resistance towards conventional antibiotics, antimicrobial nanoparticles appeared as one of the best alternatives. In the present study, zinc oxide nanoparticles (ZnO NPs) were prepared using ethyl acetate extract of Ageratum houstonianum Mill. leaf. The ZnO NPs were analyzed using different characterization techniques. A characteristic stretching frequency at 498 cm −1 in the FTIR spectrum and the XRD result indicated the formation of ZnO. FESEM and HRTEM images revealed that ZnO NPs were spherical‐shaped. The zeta potential data implied that the produced ZnO NPs were anionic (−15.5 mV). Furthermore, the antimicrobial activity of ZnO NPs was performed against Pseudomonas aeruginosa , Escherichia coli , Staphylococcus aureus , Streptococcus pyogenes , and Klebsiella pneumoniae and showed the highest efficiency toward S. aureus with a zone of inhibition of 14.3 ± 0.3 mm. Synthesized ZnO NPs exhibited antioxidant activity with an IC 50 of 110.59 µg/mL. The in vitro cell study with synthesized ZnO NPs ascertained that the NPs exhibited anticancer activity against breast cancer cell lines (MCF‐7) with the IC 50 value of around 65 µg/mL. Overall, these findings showed that ZnO NPs synthesized using A. houstonianum Mill. leaf extract have antibacterial, antioxidant, and anticancer activities and could be used for therapeutic applications.