The antimicrobial potential of essential oils and their nanoparticulate formulations as effective antifungals

Abstract

Fungal infections present a challenge when it comes to topical treatment failure thereby necessitating the need for more effective topical delivery systems. Essential oils have demonstrated noteworthy antifungal activity; however, their volatility limits therapeutic use for skin conditions. This study aimed to investigate the antifungal activity of essential oils alone and in combination. Thereafter, antifungal nanoparticulate formulations were designed using three essential oil combinations against <i>Microsporum canis</i>, <i>Trichophyton mentagrophytes</i> and <i>Candida albicans</i>. The antifungal activity was investigated using the broth microdilution assay to determine the minimum inhibitory concentration (MIC). The formulations were prepared by forming nanoparticles (polymer-based and composite lipid-polymer-based systems), with the preferred formulation encapsulating the essential oil combinations. Characterisation of the formulations was performed with a Zeta-sizer and using attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR). The <i>in vitro</i> antifungal activity of the three nanoparticulate formulations was then determined, where a significant (p = 0.002) increase in the average antidermatophyte activity could be observed for all three formulations. The combination of <i>A. sativum</i> and <i>C. martinii</i> displayed the lowest MIC value across all three reference strains (MIC values 0.06-0.38 mg mL^-1) and the formulation maintained the antifungal activity with MIC values ranging 0.08-0.36 mg mL^-1. A successful combination of essential oils with antifungal activity was achieved thereby emphasising an effective nanoparticulate formulation.