ENDO: Essential Oils May Cause Prepubertal Gynecomastia
Researchers find that lavender oil and tea tree oil have estrogenic and anti-androgenic activities
TUESDAY, June 27 (HealthDay News) -- Over-the-counter shampoos, lotions and soaps containing essential oils may disrupt the endocrine system and cause gynecomastia in boys aged 5 to 10, according to research presented this week at ENDO 2006, the Endocrine Society's annual meeting, in Boston.
Derek V. Henley, M.D., of the University of Colorado School of Medicine in Denver, and colleagues observed several boys who presented with idiopathic prepubertal gynecomastia. They found that all but one of the boys had been using over-the-counter health care products containing lavender and/or tea tree oil.
The researchers used a human breast cancer cell line, MCF-7, that had been transfected with an estrogen-responsive plasmid to study the oils' estrogenic activity. Treatment with lavender and tea tree oil boosted luciferase activity in a dose-dependent manner, which could be attenuated by an estrogen receptor antagonist. The researchers also used MDA-kb2 cells stably transfected with the androgen-responsive MMTV-luc reporter plasmid to study the oils' anti-androgenic activity. Treatment of the cells with an androgen receptor agonist, dihydrotestosterone, caused a fourfold increase in luciferase activity, which was reduced by 50 percent by both oils.
"Taken together, these data provide evidence that lavender oil and tea tree oil exhibit estrogenic and anti-androgenic activities in vitro," the authors conclude.