Antimicrobial Activity of Essential Oil of Boswellia carterii Birdw. Oleo Gum Resin and Its Chemical Composition

Boswellia carterii oleo gum resin (Frankincense) is a part of the traditional medicine of the Arab region that is used in folk medicine for the treatment of various diseases. The chemical composition of the B. carterii oleo gum resin essential oil was determined using gas chromatography-mass spectrometry (GC/MS) analysis, and the antimicrobial activity of the essential oil was evaluated using disc-diffusion assay, minimum inhibitory concentration (MIC) of the essential oil was determined, and cell morphology was evaluated by scanning electron microscopy (SEM). The GC/MS analysis of the essential oil revealed the presence of 22 compounds that represented 98.33% of the total constituents of the essential oil, out of which the majority of the components were monoterpenes (91.194%) and 7.139% were sesquiterpenes. The essential oil was recorded to have antibacterial properties against a variety of bacterial and fungal pathogens. However, the antimicrobial activity of the essential oil was prominent against Escherichia coli and Fusarium solani. The MIC of the essential oil against the tested bacterial and fungal pathogens ranged between 1.25 to 2.5 mu L/mL and 0.625 to 1.25 mu L/mL, correspondingly. In addition, B. carterii oleo gum resin essential oil also altered the morphology of E. coli and F. solani, as confirmed by the SEM analysis. These findings reinforce the suggestion that B. carterii oleo gum resin essential oil has the potential to be used as a natural antimicrobial agent against bacterial pathogens that cause food-borne diseases and plant pathogenic fungi.