Antimicrobial activity of Xylosma prockia (Turcz.) Turcz. leaves against Candida parapsilosis in vitro.

Resumo

Candida parapsilosis is a prevalent pathogen that contributes to candidemia in Brazil. The therapeutic options available for treating candidiasis are limited due to the high toxicity and high fungal resistance to clinically available drugs. In light of these challenges, there is a growing interest in exploring natural products as a potential source for discovering and developing novel antimicrobial agents. In this study, we aimed to investigate the antifungal activity of the leaves of Xylosma prockia (Turcz.) Turcz. against C. parapsilosis ATCC 22019 in vitro. The minimum inhibitory concentration (MIC) of the ethanolic extract and its fractions was determined using the broth microdilution method. The fraction with the lowest MIC was selected for subsequent experiments, which included a time-kill curve assay, quantification of ergosterol content by spectrophotometry, analysis of lipid peroxidation using the reactive thiobarbituric acid method and the use of fluorescent probes to determine oxidative and nitrosative species. The ethanolic extract, butanol, dichloromethane, and ethyl acetate fractions inhibited fungal growth at concentrations below 100 mg/L. The ethyl acetate fraction inhibited the growth cell at the lowest concentration (16 mg/L). The time-kill curve test showed that this fraction has a fungicidal effect. The mechanism of action does not appear to be related to ergosterol synthesis, as the fraction did not affect this sterol content. Interestingly, the fraction induced an oxidative and nitrosative burst, leading to lipid peroxidation. The results of this study indicate that the ethyl acetate fraction of X. prockia leaves has antifungal potential due to oxidative damage.