As fases fenológicas de Commiphora leptophloeos influenciam no seu potencial contra biofilme de Candida spp.?

Abstract

The increase in yeasts resistant to existing antifungal drugs has raised interest in research for bioactive natural products. However, environmental factors influence the production of secondary metabolites by plants, which may interfere with the viability of production. Thus, we investigated whether the phenological phases of Commiphora leptophloeos (Mart.) J. B. Gillett (Burseraceae), a plant species from the semiarid region of Brazil, influence the antibiofilm activity of Candida spp. alone and in the presence of fluconazole. Leaves and bark of the plant were harvested in two phenological phases, i.e. with leaves/flowers (harvest 1) and with fruits (harvest 2) and ethanolic and hexanic extracts were prepared from this material. The MIC and MFC of the extracts were determined, and the tests were performed against biofilms in formation and in preformed biofilms of Candida albicans (URM 4387), C. krusei (URM 6352) and C. tropicalis (URM 4262), using two methodologies: 1) microdilution and colorimetric quantification with crystal violet and 2) cell viability with methylene blue. In both methodologies it was observed that the extracts presented effect against the yeasts with a MIC between 1mg/ml and 2mg/ml, and CFM equal or higher than 2mg/ml. It was noted that the extracts reduced the viable cells of the biofilms by more than 50%. It was no synergistic effect with fluconazole. Furthermore, High Performance Liquid Chromatography analysis showed higher amounts of gallic acid in the bark than in the leaves of C. leptophloeos with no difference between the harvests for this part of the plant. In the leaves, the extract from the second harvest showed a higher amount of gallic acid than the first one. It was noticed that the extracts of the second harvest presented better effects on the formation of biofilms of Candida spp. while the extracts of the first harvest from the leaves presented better results on the pre-formed biofilms, and among the bark extracts, the one from the second harvest stood out. These results suggest that the phenological phases of C. leptophloeos exert little effect on the antibiofilm activity, however, the promising effect of its metabolites on pre-formed biofilms of Candida spp. was highlighted.