In Vitro and In Vivo Evaluation of the Anticancer and Anti-inflammatory Activities of 2-Himachelen-7-ol isolated from Cedrus Libani.

Cedrus libani is a majestic evergreen tree native to the Mediterranean mountains of Lebanon, Syria and Turkey. In this study, the tree heart wood was extracted using hexane to produce C. libani oil extract (CLOE) as a dark oil. GCMS analysis of CLOE identified up to 30 compounds whereby 2-himachalen-7-ol (7-HC) was the most abundant (40%). 7-HC was isolated using column chromatography and the identity of the white crystalline solid was confirmed via NMR spectroscopy and X-Ray Crystallography. 7-HC demonstrated potent cytotoxic activity against several human cancer cell lines including brain (SF-268, IC50 8.1 μg/mL) and colon (HT-29, IC50 10.1 μg/mL; Caco-2, IC50 9.9 μg/mL) with ovarian (Sk-OV-3, IC50  > 50 μg/mL) cells being the most resistant. However, while HT-29 displayed resistance to Cisplatin, 7-HC was 8-10 folds more potent. Co-treatment with 7-HC and Cisplatin showed a significant synergistic anti-proliferative effect against SF-268, HT-29 and Caco-2 cells. 7-HC also exhibited significant anti-inflammatory effect in formalin-induced paw edema in rats. Western blot analysis revealed that 7-HC displayed dose dependent inhibition of LPS-induced COX-2 protein expression in isolated rat monocytes. The present study demonstrates that 7-HC possesses promising anticancer and anti-inflammatory activities, and may serve as a lead molecule in cancer therapy.