Anti-cancer activity of 2-himachalen-7-ol isolated from Cedrus libani

Cedrus libani is among the oldest Cedrus species in the Mediterranean region. Its essential oil has been utilized in folk medicine in Lebanon and was recently shown to possess antileukemic activity [1]. The current study aims to isolate and characterize the major compound responsible for anticancer activity. Cedrus wood (100 g) was extracted with hexane using a soxhlet apparatus to obtain 2.4 g of crude oil. The oil (1 g) was then eluted with 9:1 hexane:ethyl acetate using a silica gel-based column to yield 2-himchalene-7-ol as a white crystalline solid (125 mg, 0.3%). The identity of the sesquiterpene was determined by GC-MS, 13C NMR and X-ray Crystallography. To the best of our knowledge, this is the first time that 2-himachalene-7ol has been isolated from the wood of Cedrus libani. 2-Himachalene-7-ol was then tested against brain cancer cells (SF) and colon cancer cells (Caco-2) at doses ranging between 1 and 25 ug/mL using a WST kit. Results showed a remarkable anti-proliferative effect with IC50 values ranging between 5 – 7 ug/mL and IC99 values ranging between 11 – 13 ug/mL. In conclusion, the anticancer effect of the Cedrus Libani essential oil could be attributed to its major constituent, 2-himachalene-7-ol.