In vitro anti-biofilm activity of Boswellia spp. oleogum resin essential oils

To evaluate the anti-biofilm activity of the commercially available essential oils from two Boswellia species. The susceptibility of staphylococcal and Candida albicans biofilms was determined by methyltiazotetrazolium (MTT) staining. At concentrations ranging from 217·3 μg ml⁻¹ (25% v/v) to 6·8 μg ml⁻¹ (0·75% v/v), the essential oil of Boswellia papyrifera showed considerable activity against both Staphylococcus epidermidis DSM 3269 and Staphylococcus aureus ATCC 29213 biofilms. The anti-microbial efficacy of this oil against S. epidermidis RP62A biofilms was also tested using live/dead staining in combination with fluorescence microscopy, and we observed that the essential oil of B. papyrifera showed an evident anti-biofilm effect and a prevention of adhesion at sub-MIC concentrations. Boswellia rivae essential oil was very active against preformed C. albicans ATCC 10231 biofilms and inhibited the formation of C. albicans biofilms at a sub-MIC concentration. Essential oils of Boswellia spp. could effectively inhibit the growth of biofilms of medical relevance. Boswellia spp. essential oils represent an interesting source of anti-microbial agents in the development of new strategies to prevent and treat biofilms.