Detailed compositional experiments of Boswellia carterii, sacra, papyrifera and occulta frankincense, including the first discussion of the contents of grades 1-4 of Boswellia papyrifera resin were carried out via hydrodistillation and maceration in common laboratory solvents. Hydrodistillation of these resins found the major compounds to be α-pinene for Boswellia carterii and Boswellia sacra (62-69% and 63-80% respectively), octyl acetate for Boswellia papyrifera (54-90%) and methoxydecane for Boswellia occulta (49-73%). Maceration experiments found high triterpene content in all the resins, made up mostly of boswellic acids, but high value compounds incensole and incensole acetate were found in large content in Boswellia papyrifera and Boswellia occulta extracts, with cumulatively between 9-15% of the resin mass made up of them after isolation via column chromatography.
Investigations into extractions using Supercritical CO2 were performed on Boswellia carterii and Boswellia occulta resins. Extracting with a flow rate of 10 g/min CO2 in a 100 mL extraction vessel at 40oC and 100 bar pressure afforded α-pinene rich (24-49%) essential oil fractions from Boswellia carterii resin (7.7-9.1% mass recovery based on the resin mass). Using the same flow rate and extraction vessel separately on successive Boswellia occulta resin at 40-50oC and 90-300 bar pressure resulted in the isolation of the high value compound incensole (18% mass recovery based on the resin mass, 80% purity determined by GC/MS)
Furthermore, following a series of simple, cost-effective steps such as maceration in petroleum (40-60), low quantity stationary phase column chromatography experiments and vacuum distillation using a Kugelrohr, high incensole acetate content fractions were isolated from extracts of Boswellia occulta and grades 1-4 of Boswellia papyrifera (up to 20% mass recovery based on the resin mass, 83% purity determined by HPLC)