Synthesis, Characterization, and in Vitro Antifungal Activity of Solid Lipid Nanoparticles Containing Mentha×piperita L. Essential Oil

The use of essential oils and new drug delivery systems have been considered two approaches for controlling plant pathogenic fungi. This study aimed to synthesize, characterize, and evaluate the antifungal activity of Solid Lipid Nanoparticles (SLNs) incorporating Mentha×Piperita L. Essential oil (MPE) compared to the free MPE. In the present study, the formulations of SLNs incorporating MPE (MPE-SLNs) were synthesized by high-shear homogenization and ultrasound method, and they were assessed by Z-average diameter, particle size distribution, Zeta potential, leakage stability during 6 months of storage, encapsulation efficacy, and morphological properties of the SLN formulations. The results indicated that the particle size of MPE-SLN formulations was 155.5±4.7 nm with a PDI of 0.156±0.012, a Zeta potential of -15.93±0.87 mV, and encapsulation efficacy of about 88±0.88%. They were physically stable for 6 months of storage. The results also showed that the in vitro minimum inhibition concentration for MPE on the fungal microorganisms, Rhizoctonia solani and Rhizopus stolonifer, were 2,000 and 1,000 ppm, respectively, and for MPE-SLNs it was 1,000 and 750 ppm, respectively. Therefore, the antifungal activity of MPE-SLNs was more significant than MPE, and none of the fungi were susceptible to essential oil-free SLNs. Based on the results, MPE-SLNs can be used for the safe preservation of a wide array of foods and agricultural products.