Antimicrobial Properties of Zinc Oxide Nanoparticles Synthesized from Lavandula pubescens Shoot Methanol Extract

Abstract

We report on employing in vitro biosynthesized ZnO nanoparticles using L. pubescens shoot methanol extract (50 and 100 mg LP–ZnO NPs) to examine their antimicrobial efficacy against Pseudomonas aeruginosa (ATCC27853), Staphylococcus aureus (ATCC 29213), Aspergillus niger (ATCC 16404 NA), and Aspergillus terreus (TCC 10029). The formation and stability of the investigated ZnO nanoparticles were proven by transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FT-IR), UV–vis spectroscopy, X-ray diffraction (XRD), and thermal gravimetric analysis (TGA). The ZnO nanoparticles were rod-shaped (width: 10.76–30.93 nm). The nanoparticles in dimethyl sulfoxide (DMSO) outperformed their water counterparts in terms of their zones of inhibition (ZIs) (marginal means of 12.5 and 8.19 mm, respectively) and minimum inhibition concentrations (MICs) (means of 4.40 and 8.54 mg/mL, respectively). The ZI means for S. aureus, P. aeruginosa, A. terreus, and A. niger were 10.50, 6.13, 12.5, and 11.5 mm, respectively. When treating S. aureus and P. aeruginosa, the ZI of the 50 mg LP–ZnO NPs in water was better (14 mm), with a lower MIC and lower minimum bactericidal/fungicide concentrations (MBC/MFC) (7.22 and 4.88 mg/mL, respectively) than the ZnO and control drugs. The SEM images showed cellular alterations in the surface shapes after the LP–ZnO-NP treatments. Biosynthesized LP–ZnO NPs could have beneficial antibacterial properties, which could allow for future contributions to the development of new antimicrobial drugs.