Lavender essential oil is widely used ingredient in cosmetic products, known for its pleasant smell and its calming effect. Beside its therapeutic effects and the uses of lavender essential oil in aromatherapy, increasing number of papers report on the association of lavender essential oil and endocrine system. A few clinical cases have described an unusual occurrence of gynecomastia in young healthy children, especially in boys. All patients were using care products which contained lavender essential oil at the time, and following the termination thereof, the gynecomastia disappeared. Gynecomastia is a state associated with steroid hormones signal disorder, which manifests with higher secretion of estrogen hormones and, consequently, in breast growth. In the scope of this Bachelor’s thesis, we have evaluated the endocrine and reproductive toxicity of lavender essential oil components using in silico methods. The selection of the examined compounds was based on the essential oil components reported in the literature. Using Endocrine Disruptome and VegaNIC, we predicted the binding of lavender essential oil components on nuclear hormone receptors, while T.E.S.T, Derex Nexus and VegaNIC were used to predict their reproductive toxicity. The generated results of hormone receptor binding probability indicated a high possibility for lavender essential oil components to bind antagonistic conformation of the androgen receptor and the agonistic conformation of the estrogen receptor. The in vitro study reported in the literature revealed weak antiandrogen and estrogen effects of lavender essential oil, thus corroborating our prediction. On the other hand, the positive results of reproductive toxicity predictions are not in agreement with the literature, namely no results linking lavender essential oil to reproductive toxicity have been published to date to support our predictions. This shows us that in silico methods are for now still not efficient and accurate enough for predicting something as complex as reproductive toxicity.
According to our endocrine effect predictions, there is a real possibility of developing gynecomastia in children using cosmetic products with lavender essential oil. The lipophilicity of essential oil and thinner child skin facilitate the penetration of lavender essential oil into the skin. Therefore, further in vitro as well as in vivo investigations are needed to determine the effects of lavender essential oil on the endocrine system. Nevertheless, the in silico predictions can serve as a good starting point for further research, if interpreted by a professional.