Endometriosis lesion growth inhibition and immune modulation function of thymol in vitro and in vivo

Thymol, a phenolic monoterpene derivative found in the essential oil of Thymus vulgaris L., Lamiaceae, is currently under investigation for potential applications in pharmaceuticals, functional foods, and cosmetics. Despite ongoing research in these areas, the potential therapeutic effects of thymol on endometriosis remain unconfirmed. Endometriosis, characterized by the growth of endometrial tissue outside the uterus. Available treatment options, including medications and surgery, have limitations and are no curative. To address these limitations, our study aimed to explore the therapeutic potential of thymol in endometriosis, through simultaneous in vitro and in vivo investigations. Our results indicate that thymol induces antioxidant activity and regulate intracellular calcium ions. Further thymol administration reduced the size of endometriosis lesions in animal models and modulated immune responses, resulting in alterations in spleen populations of CD4⁺ T and CD8⁺ T cells and macrophages, as well as changes in the expression of cytokine-related genes. Overall, our findings suggest that thymol holds promise as a therapeutic agent for endometriosis.