Antibacterial and antioxidant activity of oil-in-water nanoemulsion of Mentha pulegium essential oil and extract

The medical application of oil-in-water nanoemulsion has been expanded due to its special properties. Nanoemulsions based on medicinal plants are important because of the simple and fast preparation method, high efficiency, and economic efficiency.

In this study, the oil-in-water nanoemulsion was prepared containing Mentha pulegium essential oil as the oil phase, Mentha pulegium extract as the aqueous phase, and span 80 surfactant for 30 minutes using homogenizer. The properties of samples were investigated. Chitosan was used as the natural biological material to modify the optimal nanoemulsion due to its biocompatibility, biodegradability, and antibacterial properties. The samples were evaluated by methods of dynamic light scattering (DLS) to investigate size and size distribution, transmission electron microscopy (TEM) to measure size and shape, and zeta potential to determine stability. Antibacterial activity, antioxidant activity, and cytotoxicity of the samples were investigated.

The results of the antibacterial activity of the essential oil, its extract, and nanoemulsions against gram-negative bacteria escherichia coli (E.Coli) and gram-positive bacteria staphylococcus aureus (S.Aureus) showed that these materials are suitable candidates instead of chemical drugs to deal with strains. The antioxidant activity of the samples was observed based on the measurement of total phenolic compounds and free radical inhibition. Also, the samples are not cytotoxic on healthy cells.

Based on the results, oil-in-water nanoemulsion containing essential oil as the oily phase and extract as the aqueous phase can be suitable candidates for pharmaceutical and medical applications.