Chemical composition, antibacterial and antifungal activities of essential oil from Cordia verbenacea DC leaves

Background: Cordia verbenacea is a Brazilian coastal shrub popularly known as erva baleeira. The essential oil from fresh leaves was obtained by hydrodistillation and analyzed by CG/MS. The main components were identified as -caryophyllene (25.4%), bicyclogermacrene (11.3%), -cadinene (9.%) and a-pinene (9.5%). In this study, the antimicrobial activity of Cordia verbenacea was evaluated. Materials and Methods: The minimal inhibitory concentration (MIC) of the essential oil was obtained using the broth microdilution assay (from 512 to 8 mg/ml). Results: The results showed that the essential oil presented fungistatic activity against Candida albicans and Candida krusei and antibacterial activity against Gram-positive strains (Staphylococcus aureus and Bacillus cereus) and against multiresistant Gram-negative (Escherichia coli 27), in all tests the MIC was 64 mg/ml. When the essential oil was associated to aminoglycosides (subinhibitory concentrations, MIC/8), a synergic and antagonic activity was verified. The synergic effect was observed to the amikacin association (MIC reduction from 256 mlto 64 mg/ml) in all strains tested. Conclusion: The essential oil of Cordia verbenacea influences the activity of antibiotics and may be used as an adjuvant in antibiotic therapy against respiratory tract bacterial pathogens.