Figure 2. Antiandrogenic Activity of Lavender and Tea Tree Oils in Breast-Cancer (MDA-kb2) Cells.
MDA-kb2 cells that were stably transfected with the MMTV-luciferase (firefly) plasmid were treated for 24 hours with increasing concentrations of lavender oil (Panel A) or tea tree oil (Panel B) in the presence or absence of DHT. The firefly luciferase activity was normalized to the total protein content for each sample. The data were averaged and plotted as the average (±SE) fold increase above vehicle control of three independent experiments performed in quadruplicate. The upper dashed lines in Panels A and B represent treatment of the cells with DHT alone, and the lower dashed lines represent treatment with DHT in the presence of flutamide. For the comparison between treatment with DHT and treatment with ethanol (the solvent control) alone, P<0.001. For the comparison between treatment with either DHT plus flutamide or DHT plus either lavender oil (at 0.001% and 0.005%) or tea tree oil (at 0.005%) and treatment with DHT alone, P<0.001. For the comparison between treatment with DHT plus tea tree oil at 0.0005% and treatment with DHT alone, P<0.05. For the comparison between treatment with tea tree oil at 0.001% and treatment with DHT alone, P<0.01. In Panel C, MDA-kb2 cells were treated with 0.1 nM DHT for 24 hours in the presence or absence of 0.005% (vol/vol) lavender oil, 0.005% (vol/vol) tea tree oil, or 1 µM of flutamide. Real-time PCR was performed to measure the steady-state mRNA concentrations of CYP4F8, C1orf116, UGT2B28, and SEC14L2. All values were normalized to β2-microglobulin, and each data point represents the average increase above vehicle control of the values obtained from three independent experiments performed in duplicate.