Seasonal variation, chemical composition and biological activity of the essential oil of Cordia verbenacea DC (Boraginaceae) and the sabinene

• The main phytocompound identified in the EOCV was sabinene.
• Was verified the variation of the chemical composition of the essential oil during one year.
• Was demonstrated the antibacterial activity of the essential oil, sabinene and hydrate sabinene.
• Was demonstrated the modulatory activity of bacterial resistance to aminoglycosides.

Cordia verbenacea DC (Boraginaceae), popularly known as “Erva Baleeira,” has been widely studied with respect to its chemical and pharmacological properties, and its anti-inflammatory, analgesic and anti-ulcerogenic activities have been demonstrated. The objective of this study was to determine the essential oil content with regard to time of collection of leaves and to evaluate the antibacterial activity and antibiotic-modifying activity of the oil, sabinene and sabinene hydrate against multidrug-resistant strains. GC/MS analysis showed that in samples of the essential oil obtained at different times over one year, there was qualitative and quantitative variation in chemical composition, with statistical significance (p <0.001 and p <0.05). The MIC of essential oil, sabinene and sabinene hydrate was ≥1024 μg/mL, demonstrating no clinically relevant antibacterial activity. In tests for modulation of bacterial resistance to aminoglycosides, essential oil, sabinene and sabinene hydrate showed significant changes (p <0.001) in MIC values, enhancing the effect of the antibiotics tested, thereby demonstrating synergistic potential. These results serve as a reference for choosing the best time to obtain the oil according to the constituent of interest, as well as for using the oil and its constituents as modifying agents of bacterial resistance to aminoglycoside.