Antimicrobial synergy of<i> Lavandula</i><i> angustifolia</i> L. and<i> Rosa</i><i> damascene</i> L. essential oils: Preparation of herbal lip formulations

Increasing concerns about the potential toxicity of heavy metals such as lead and various chemical compounds commonly found in synthetic lip care products have increased the demand for herbal alternatives. This study aimed to formulate a low-toxicity, natural, antimicrobial lip product using Isparta-grown Lavandula angustifolia L. (lavender) and Rosa damascena L. (rose) essential oils. Cosmetic grade oils, chitosan, lanolin, and ethylhexylglycerin were included. Gas chromatography determined essential oil components, while standard methods assessed the formulations' physicochemical properties (pH, viscosity, melting point, weight deviation). Furthermore, microbiological tests, safety limit analyses, and in vitro antimicrobial activity examinations were conducted for a comprehensive evaluation of the formulations. GC analyses revealed distinct component profiles, with rose oil mainly composed of beta-citronellol, geraniol, and nonadecane, while lavender oil featured linalool, linalyl acetate, and terpinen-4-ol. The developed LF-9 formulation successfully met the basic requirements by exhibiting homogeneity, an acceptable pH level, resistance to microbial contamination and stability maintained for six months. The strong antimicrobial activity of the formulation against E. coli, B. cereus, and C. albicans, especially due to the effect of lavender oil, was also confirmed by the relevant Minimum Inhibitory Concentration (MIC) values. These results demonstrate the potential of developing natural and safe lip care products by utilizing the antimicrobial properties of lavender and rose essential oils and position the LF-9 formulation as an effective natural alternative to synthetics due to its superior qualities.