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Gummy exudates of Boswellia carterri Birdw and Boswellia serrata have been traditionally used as anti-arthritic and anti-cancer mediations. Boswellic acid and its acetates isolated from these gummy exudates were found to be inhibitors of topoisomerases and to be non-redox, non-competitive specific inhibitors of 5-lipoxygenase (5-LOX). 5S-hydroxy-6,8,11,14-eicosatetraenoic acid, the product of 5-LOX activity, has been found to be both mitogenic and antiapoptotic in prostate cancer cells. The growth inhibitory effect of boswellic acid acetates (BAA), Boswellin (a crude methanol extract), and BEF (a chloroform extract) were used to test their ability to inhibit cell growth and to induce apoptosis in prostate cancer cells. The cell growth inhibitory effects were measured by an MTT assay and apoptosis was measured by a TUNEL assay in three prostate cancer cell lines, LNCaP, DU-145 and PC-3. BAA, Boswellin, and BEF had similar effects in the three prostate cancer cell lines tested. The IC50s of BAA, Boswellin, and BEF in LNCaP cells were 7.5, 8.0 and 12.5 ug/ml, respectively. To standardize the Boswellin and BEF based on BAA content using HPLC, only 3% and 64% of BAA was detected in Boswellin and BEF, respectively. These findings suggest that BAA was not the sole active component against prostate cancer growth in Boswellin and BEF. Using immunocytochemical and immunoblotting techniques, it was found that 5-LOX protein was highly expressed in all of the three prostate cancer cell lines. MK886, a 5-LOX inhibitor, enhanced BAA- and BEF-induced cell growth inhibition and apoptosis significantly. These data suggest that crude extracts Boswellia carterri Birdw and Boswellia serrata alone or in combination with a 5-LOX inhibitor may have therapeutic potential in the treatment of prostate cancer. (This work was supported by NIH R21AT001539).

[Proc Amer Assoc Cancer Res, Volume 46, 2005]

American Association for Cancer Research
2005