Nanoemulsion of Thymus capitatus and Origanum vulgare essential oil: stability, antimicrobial and cytotoxic properties

This research focuses on the assessment of cytotoxic and antimicrobial properties of Thymus capitatus essential oil (TEO) and Origanum vulgare essential oil (OEO), before and after encapsulation in nanoemulsions, prepared utilizing high-pressure homogenization. These plants, indigenous to northern Albania and Mediterranean regions, produce EO with notable biological and cytotoxic activities. However, volatility, poor solubility, and chemical instability limit their practical application. Incorporating these oils into NE aims to enhance their stability and biological activity. The antimicrobial efficacy of the EO exhibited variability against different strains, showing particular effectiveness against E. coli ATCC 25922, S. aureus ATCC 29213, and C. albicans ATCC 10231, with no effect was observed against P. aeruginosa ATCC 27853. The EO-loaded NE exhibited enhanced cytotoxicity against MCF7, DU 145, and HT-29 cancer cell lines compared to the free oil. Encapsulation was found to augment the bioactivity of these volatile oils, with TEO-NE demonstrating superior cytotoxic effects than OEO-NE. Following encapsulation, OEO exhibited superior antimicrobial efficacy relative to TEO against S. aureus, E. coli, and C. albicans. Our results suggest that NE may enhance the cytotoxic and antimicrobial potential of the EOs, in different manner among EO used. The encapsulation of TEO and OEO in NE shows promising therapeutic potential, although further studies are required. However, these conclusions are drawn from in vitro analyses, underscoring the need for subsequent in vivo studies to ascertain this innovative clinical safety and efficacy.