Assessment of anti-invasive activity of Boswellia sacra essential oil. Matrigel basement membrane matrix (100 μl) was transferred to each well of 96-well culture plates and allowed to polymerize at 37 oC. MDA-MB-231 cells (4 × 104) were resuspended in 100 µl growth media and added on the top of the polymerized Matrigel (A and B). In separate wells, cells were either mixed with 100 µl of 78 oC essential oil at (C) 1:800 or (D) 1:600 dilution, or 100 oC essential oil at (E) 1:1,500 or (F) 1:1,200 dilution and layered on the top of Matrigel. Formation of vascular-like networks was assessed at 24 hours following oil treatment. The capabilities of MDA-MB-231 cells in forming networks of tubes and Boswellia sacra essential oil in suppressing the cellular network formation on Matrigel are observed at 100× magnification. Experiments were repeated at least 3 times and representative images are presented.