Própolis verde brasileira da caatinga: alternativa antimicrobiana inovadora frente a patógenos críticos

Abstract

Despite the severe statistics associated with infections caused by Cryptococcus spp., and multidrug-resistant bacteria, the therapeutic options remain limited. In this context, brazilian propolis is a promising antimicrobial source. This study evaluated the in vitro antifungal, antibacterial, and antibiofilm activities of ethanolic extract of BGPc and its in vivo toxicity. Antimicrobial activity was assessed by determining minimum inhibitory concentration (MIC) and minimum fungicidal and bactericidal concentrations (MFC and MBC) and the antibiofilm activity through determination of MICB50 and IC50. In addition, the living and dead cells of the biofilm was assessed by fluorescence microscopy, while biofilm morphology was evaluated by Scanning Electron Microscopy (SEM). Furthermore, the toxicity of BGPc was evaluated in Caenorhabditis elegans larvae. BGPc showed MIC values ranging from 23.4 to 46.9 µg/mL against Cryptococcus spp. and 25 to 400 µg/mL against bacteria. Antibiofilm assays revealed significant reductions in biofilm biomass and cell viability, with MICB₅₀ values for yeast of 11.7–3000 µg/mL and IC₅₀ values of 2.63–686.7 µg/mL, while bacterial MICB₅₀ ranged from 25 to 200 µg/mL and IC₅₀ from 0.47 to 11.44 µg/mL. Microscopic analyses demonstrated a large quantity of dead cells and marked disruption of the biofilm after treatment. In vivo assays using Caenorhabditis elegans revealed no significant toxicity at concentrations up to 6.000 µg/mL. Therefore, BGPc demonstrates significant potential as an antimicrobial and antibiofilm agent.