Modulating effect of (+) – α – pinene on the activity of antimicrobials that interfere on protein synthesis and bacterial genetic material

The discovery of new molecules with antimicrobial activity, and the understanding of the mechanisms of action, are important strategies against multiresistant pathogens. The positive enantiomer of α-pinene appears as an alternative to combat them, since it inhibits the growth of microorganisms, including strains of S. aureus, which gives the possibility of its use as an antimicrobial agent, isolated or in combination with other drugs. Therefore, the main goal of this study is to evaluate the modulating effect of (+)–α–pinene on the activity of synthetic antimicrobials that act on protein synthase and interfere with bacterial genetic material. The modulating effect of (+)–α–pinene on the activity of antibiotics for clinical use on some S. aureus strains was studied using the modified disc-diffusion method. The disks contain the following antimicrobials: Ciprofloxacin 5 μg, Tetracycline 30 μg, Nitrofurantoin 300 μg and Rifampicin 5 μg. 50 microliters of (+) - alpha-pinene (160 µL/mL) were added to the disks containing the antimicrobials to verify the modulating effect of monotrepene. Indifferent activity was observed in the association between the phytoconstituent and the four tested antimicrobials. Further studies using new methods in order to evaluate the antimicrobial activity of the association between the (+)–α–pinene and commercial antimicrobials are still needed.