Chemical composition and antimicrobial activity of some oleogum resin essential oils from Boswellia spp. (Burseraceae)

The chemical composition of Boswellia carteri (Somalia), B. papyrifera (Ethiopia), B. serrata (India) and B. rivae (Ethiopia) oleogum resin essential oils was investigated using GC-MS to identify chemotaxonomy marker components. Total ion current peak areas gave good approximations to relative concentrations based on GC-MS peak areas. B. carteri and B. serrata oleogum resin oils showed similar chemical profiles, with isoincensole and isoincensole acetate as the main diterpenic components. Both n-octanol and n-octyl acetate, along with the diterpenic components incensole and incensole acetate, were the characteristic compounds of B. papyrifera oleogum resin oil. Hydrocarbon and oxygenated monoterpenes were the most abundant classes of compounds identified in the B. rivae oleogum resin oil. The antimicrobial activities of the essential oils were individually evaluated against different microorganisms including fungi, Gram-positive and Gram-negative bacteria strains. The essential oils with the best activity against fungal strains were those obtained from B. carteri and B. papyrifera with MIC values as low as 6.20 microg/ml. The essential oil of B. rivae resin showed the best activity against C. albicans with a MIC value of 2.65 microg/ml.