Development of an Artemisia absinthium Essential Oil Nanoemulsion and Evaluation of Its Safety, Stability, Antimicrobial and Antioxidant Properties

Antimicrobial resistance is driving the urgent need for novel antimicrobials. Nanoemulsions (NEs) offer alternatives to traditional antimicrobials by improving the physiochemical and biological properties of bioactive compounds. Artemisia absinthium essential oil (Art-EO) has antimicrobial and antioxidant properties, although its medical applications are limited by hydrophobicity and potential cytotoxicity. To improve these properties, this study investigated an NE loaded with Art-EO (Art-EO NE) extracted via hydrodistillation from A. absinthium grown in Saudi Arabia. Extracted with 0.92% (v/w) yield from the aerial parts of A. absinthium, Art-EO was analysed by gas chromatography–mass spectrometry, revealing 29 compounds. The Art-EO NE, prepared using ultrasonication, showed a droplet size of 116 ± 0.2 nm, polydispersity index of 0.14 ± 0.0, and zeta potential of −23.9 ± 1.0 mV determined by dynamic and electrophoretic light scattering. The NE remained physically stable for two months and exhibited antimicrobial activity for one week. Compared to the Art-EO aqueous extract (minimum inhibitory concentration (MIC): 20% v/v Art-EO), the Art-EO NE enhanced antibacterial activity against Staphylococcus aureus by 32-fold (MIC: 0.625% v/v Art-EO). The NE also exhibited potent antioxidant activity and produced an acceptable in vivo safety profile. These findings present Art-EO NEs as effective antimicrobial and antioxidant agents.