Chemical composition and antibacterial properties of microemulsion and microemulgel formulations containing Lavandula angustifolia Mill. essential oils
Serpil Demirci Kayıran, Umay Merve Güven, Tilbe Çevikelli, Suna Kızılyıldırım, Bedirhan Yıldır, Elif Ferahoğlu, Saliha Kırıcı, Fatih Özoğul
Abstract
Lavandula L. species are highly regarded for their cosmetic, culinary, and medicinal uses. The essential oil of Lavandula angustifolia Mill. has been recognised worldwide for its sedative, antidepressant, antiseptic, antifungal, relaxing and antiemetic properties, as well as its low toxicity risk. The aim of this research was to investigate the chemical constituents and antibacterial efficacy of microemulsion and microemulgel forms of the flowers of L. angustifolia . Formulations of microemulsions and microemulgels were prepared using the essential oils of L. angustifolia performing the globule size, zeta potential, pH, viscosity, rheology, spreadability, and texture profile to evaluate the characteristics of the formulations. Pseudoternary phase diagrams were constructed for formulations comprising an oil, mixed surfactant, and water emulsion system along with an additional quaternary component. Microemulsions were transformed into microemulgels using Carbopol 940 polymer. The antibacterial properties of these essential oils and formulations were tested against Staphylococcus aureus, E. coli, Pseudomonas aeruginosa, Streptococcus agalactiae, and Enterococcus faecalis using the broth dilution method. Gas chromatography-mass spectrometry identified 27 primary components, which were linalool, linalyl acetate, trans-β-ocimene, terpinen-4-ol, and α-terpineol, as the major constituents of the essential oils. As a result, both the essential oils and their formulations showed antibacterial activity against all tested bacterial strains. These findings indicated that L. angustifolia essential oils and formulations could be used as natural resources to develop novel and effective antibacterial agents in the food, cosmetics and healthcare sectors. • Antibacterial activities of microemulgel formulations of L. angustifolia were investigated. • Globule size, zeta potential, viscosity, rheological properties, spreadability, and texture profile were analysed. • The broth dilution method was used for the antibacterial activity of L. angustifolia essential oils and formulations. • Linalool, linalyl acetate, trans-beta-ocimene, terpinen-4-ol and α-terpineol were main components. • The essential oils and formulations can be used as effective antibacterial products for food, cosmetics and healthcare.