Thymol: properties, synthesis, mechanism of action, and applications

Thyme (Thymus vulgaris) has long been valued as both a culinary herb and a medicinal plant. Among its constituents, thymol-a key monoterpenic phenolic compound-exhibits a wide range of biological activities, including antimicrobial, antioxidant, anti-inflammatory, and insecticidal properties, which endow it with significant application potential in food-related fields. This review systematically examines the physicochemical properties, biosynthetic pathways, extraction methods, and mechanisms of action of thymol, with a particular emphasis on its prospective applications within the food sector. Traditional extraction techniques such as steam distillation remain in use, whereas emerging methods-including ultrasound-assisted extraction and supercritical fluid extraction-have markedly improved the efficiency, yield, and purity of thymol extraction. From the perspective of synthesis, thymol can be produced chemically via alkylation of m-cresol, or it can be generated biologically through the methylerythritol phosphate (MEP) pathway. Thymol exerts its antimicrobial and preservative effects primarily by disrupting microbial cell membranes and inducing oxidative stress, thereby providing the theoretical foundation for its use as a natural food preservative, packaging additive, and functional ingredient. This article further explores the value of thymol in ensuring food quality, enhancing safety control, and extending shelf life. Finally, future research directions are proposed, including optimization of biosynthetic pathways, development of formulations to enhance stability, and exploration of new potential applications at the intersection of antiviral activity, immune modulation, and food-related health.