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INVESTIGATION OF THE ACTIVITY AND MECHANISM OF ACTION OF CARVACROL AGAINST RHODOTORULA RUBRA

Jefferson Nóbrega, Paula Sousa, Kelly Mota, Laísa Cordeiro*, Francisco Andrade Júnior, Wylly Oliveira

The genus Rhodotorula is considered saprophytes. However, in recent decades they have been emerging with the ability to colonize and infect susceptible patients. Most cases of Rhodotorula infections are fungemia associated to catheters, endocarditis, cancer, acquired immunodeficiency syndrome, meningitis, and pleural tuberculosis. With increasing fungal resistance and the reduced spectrum of antifungal drugs available for clinical use, it is important that new alternatives be sought. In the context of this search for new drugs, carvacrol emerges as an option of natural origin, which has a wide range of biological activities. Thus, this study aimed to evaluate the antifungal activity of carvacrol against Rhodotorula rubra and to investigate the mode of action of this phytoconstituent. The Minimum Inhibitory Concentration (MIC) was determined by the broth microdilution method and the mechanism of action on the membrane and on the cell wall of the microorganism was evaluated by the addition of ergosterol and sorbitol to the culture medium, respectively, with subsequent verification of carvacrol MIC in the presence of these two substances. Carvacrol showed significant antifungal activity, and the concentration of 128 μg/mL inhibited the growth of all strains, while 64 μg/mL inhibited half of them. The results suggest that the mechanism of action of carvacrol occurs through binding to ergosterol present in the cell membrane and not by modifying the cell wall of the microorganism. Further studies are needed for further clarification and, thus, allow possible use of carvacrol against R. rubra. Key-words: Rhodotorula rubra; carvacrol; ergosterol, sorbitol, monoterpene.

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