Breast cell viability in response to Boswellia sacra essential oil exposure. Human breast cells (5x103) were seeded in each well of 96-well tissue culture plates in triplicate. Following adherence, cells were treated with Boswellia sacra essential oil hydrodistilled at (A) 78 oC or (B) 100 oC for 12 hours. Cell viability was determined using the colometric XTT assay at 24 hours after essential oil treatment. Data are presented as mean ± SEM from at least 4 independent experiments. * indicates statistical differences between essential oil-treated breast cancer cells and immortalized breast cells (P < 0.05).