Atividade antifúngica dos óleos essenciais de Baccharis trimera Less (D.C.) e de Origanum vulgare Linnaeus frente às linhagens causadoras de esporotricose

Abstract

Sporotrichosis is an important subcutaneous mycosis, that can affect humans and animals, which is the main etiological agent Sporothrix schenkii. The treatment of fungal infections has been of concern due to the occurrence of relapses and the emergence of strains resistant to conventional antifungal drugs (synthetic). Thus, there is a growing search for new and effective natural products with novel mechanisms of action. The objective was to identify the components of the essential oils of Origanum vulgare and Baccharis trimera and investigate their potential antifungal in vitro against four strains of S. schenckii and two of S. brasiliensis. Amphotericin B and ketoconazole were used as reference drugs. Antifungal assays were performed by means of microbiological screening and established the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) for the substances of interest. The chromatographic analysis of the essential oil of B. trimera demonstrated that β - pinene (23.4%) was the major component and in O. vulgare oil was the γ - terpinene (30.5%) . The MIC and MFC values for oil B. trimera and O. vulgare were, respectively, 125 μg/mL and 62.5 μg/mL for strain A; 500 μg/mL and 62.5 μg/mL for strain B; 125 μg/mL e 125 μg/mL for S. schenckii ATCC 1099-18; 32.25 μg/mL and 125 μg/mL for strain S. brasiliensis ATCC 5110; 62.5 μg/mL and 250 μg/mL for S. brasiliensis IPEC 17943; 125 μg/mL and 500 μg/mL for S. schenckii IPEC 15383. The action of the essential oil was characterized as a fungicide. Through the images of scanning electron microscopy may be noted that the essential oils cause the same kinds of changes that reference drugs, and in some cases greater intensity. The results obtained so far have shown promise and stimulate continuing research.