Thymol Chemotype Thymus vulgaris L. Hydrolate: Volatile Chemical Fraction Composition and Antimicrobial Activity...

The increasing prevalence of antimicrobial resistance necessitates the development of alternative antimicrobial agents derived from natural sources. This study evaluated the volatile chemical profile and antimicrobial activity of a thymol-containing hydrolate obtained from Thymus vulgaris L. against a panel of 14 clinically and economically relevant microorganisms. Headspace-gas chromatography-mass spectrometry analysis revealed thymol (79.9%) and linalool (17.4%) as the predominant constituents of the hydrolate. Antimicrobial activity was assessed using disc diffusion and broth microdilution assays to determine inhibition zones and minimum inhibitory concentrations. The hydrolate exhibited pronounced activity against Gram-positive bacteria, with the largest inhibition zones observed for Staphylococcus aureus and the lowest MIC values for the same strain (MIC₅₀ = 5.765 mg/mL; MIC₉₀ = 6.341 mg/mL). Gram-negative bacteria displayed moderate susceptibility, with MIC₅₀ values ranging from 13.605 to 15.946 mg/mL. Yeasts showed lower susceptibility (Candida albicans MIC₅₀ = 25.450 mg/mL), while filamentous fungi exhibited the highest resistance (Botrytis cinerea MIC₅₀ = 46.013 mg/mL). Overall antimicrobial efficacy followed the pattern: Gram-positive bacteria > Gram-negative bacteria > yeasts > filamentous fungi. These findings demonstrate that thymol hydrolate possesses substantial antimicrobial potential, particularly against Gram-positive pathogens, and may represent a promising natural alternative to synthetic antimicrobial agents for applications in food preservation and cosmetic formulations.