Objective: To study the constituents in the chloroform extract of olibanum and their antitumor activities.
Method: The compounds were isolated by chromatographic methods and their structures were identified on the basis of spectroscopic methods and X-ray diffraction. The antiproliferative effect of the compounds in human leukemia HL-60 cells was tested by viable cell counting.
Result: Four cembrane diterpenes were isolated and identified as incensole-oxide (1), acetyl incensole-oxide (2), incensole (3), and acetyl incensole (4).
Conclusion: Compounds 2 and 4 were isolated from the genus Boswellia for the first time. Compound 4 showed growth inhibitory effect against human leukemia HL-60 cell lines with IG50 value of (16.3 +/- 3.4) micromol x L(-1).