Atividade antifúngica e antibiofilme do oléa essencial de patchouli (Pogostemon cablin) frente a isolados de Candida albicans

Abstract

The Candida albicans species is part of the human microbiota and is associated with different types of infections. It is the most commonly isolated yeast in samples of oral cavity infections. The number of infections attributed to the Candida genus has grown significantly on a global scale and due to the rigorous and improper use of current antimicrobials, antimicrobial resistance has also increased. Pogostemon cablin Benth., popularly known as patchouli, is a medicinal herb of great relevance, with several pharmacological properties reported in the literature. The aim of this study was to evaluate the antifungal potential of P. cablin essential oil against 11 oral isolates of Candida albicans and a standard strain (ATCC90028). The chemical characterization of P.cablin was carried out using Gas Chromatography coupled with Mass Spectrophotometry (GC-MS). The antifungal activity was analyzed using the microdilution technique to determine the minimum inhibitory concentration (MIC) and the minimum fungicidal concentration (MFC). The mechanism of action of the possible antifungal activity of the phytocomplex in question was analyzed using the sorbitol and ergosterol assays. In addition, virulence factors were also investigated, such as biofilm formation capacity and morphogenesis. Nineteen molecules were identified,

including patchouli alcohol (15.11%), Δ-Guaiene (9.85%), α-Guaiene (8.06%) and α- Patchoulene (5.03%). P. cablin showed MIC and MFC values between 2 and 128 μg/mL for

the strains tested. The results suggest that this activity occurs through the complexation of the oil's constituents with the ergosterol of the fungal membrane. The essential oil slightly reduced the Morphology Index (MI) of the strains tested. For the most filamentous strain, there was a significant decrease in filament length, from 285.0 μm to 220.5 μm. In the formation of biofilms, the essential oil showed a reduction of 26% to 59% at concentrations of 4 to 40 μg/mL and in the reduction of biofilms formed, the values ranged from 49% to 68%. The essential oil of P. cablin showed a complex chemical composition and significant activity on C. albicans, which was considered fungicidal for most of the strains tested. It is suggested that this antifungal action is due to the complexation of the essential oil with the ergosterol of the fungal plasma membrane. In addition, P. cablin acted on the formation and reduction of biofilm and also exerted an influence on the morphogenesis of Candida albicans.