Correlation between VOC fingerprinting and antimicrobial activity of several essential oils extracted by plant resins against A. tumefaciens and P. savastanoi

The present work aimed to assess the antimicrobial activity of twelve essential oils extracted from plant resins of trees that grow in several tropical and subtropical regions of the world. Eleven essential oils were extracted from resins of plant belonging to the Burseraceae family (the genera Boswellia, Commiphora, Canarium and Bursera); the remaining oil was extracted from a resinous plant belonging to the Fabaceae family (genus Hymenea). The extraction was carried out using a conventional distillation method. The volatile organic compounds (VOCs) of each essential oil were analyzed with PTR‐ToF‐MS (proton transfer reaction time‐of‐flight mass spectrometry) and the antimicrobial activity was evaluated against the phytopathogens Agrobacterium tumefaciens and Pseudomonas savastanoi pv. savastanoi. The essential oils obtained from Boswellia papyrifera, B. dalzielii, B. frereana and B. rivae were the most abundant in terms of signal intensity and VOC number in comparison with the other analyzed essential oils. Furthermore, B. neglecta shared a common volatile profile with the Canarium species, as was demonstrated previously in the literature. Greater bacterial growth inhibition of A. tumefaciens was detected with the essential oils extracted from plants belonging to Boswellia species while less action was observed against P. savastanoi. Finally, a positive correlation was found between terpenes and terpenoid compounds and bacterial growth inhibition, suggesting these essential oils as a new source of bioactive compounds for the prevention, protection and treatment of plant diseases.