BIOACTIVE PROCYANIDINS FROM AÇAÍ SEED: EVALUATION OF THE ANTIMICROBIAL AND ANTIBIOFILM ACTIVITY OF THE EXTRACT AND ITS FRACTIONS WITH DIFFERENT DEGREES OF POLYMERIZATION

The açaí palm (Euterpe oleracea) is a plant native to the Brazilian Amazon and valued for the nutritional and economic importance of its fruit: the açai berry. The sharp rise in açaí consumption has resulted in significant seed waste, motivating research into alternative applications due to their economic and environmental relevance. Açaí seed extract (ASE) contains high levels of catechin and epicatechin, procyanidin-type phenolic compounds with documented antimicrobial properties. Biofilms are structured microbial communities encased in a extracellular matrix, resistant to the action of antimicrobials and the immune system. Functional amyloid proteins, such as Curli in Escherichia coli, contribute to biofilm adhesion and structural stability. Given the importance of curli in biofilm architecture, this study aims to evaluate the impact of ASE procyanidins on curli-associated biofilm formation. Curli-positive and curli-negative E. coli strains were induced to form biofilms over 48 and 72 hours. ASE was tested at different concentrations, and its effects on biofilm and bacterial growth were assessed through growth kinetics, crystal violet staining, and transmission electron microscopy (TEM). ASE did not impair bacterial growth in LB medium at 37 °C. However, a notable reduction in biofilm formation was observed, especially in curli-positive strains, suggesting that ASE may targets biofilm-associated structures rather than bacterial viability. Our findings suggest a possible anti-biofilm activity of this extract, but we now seek to elucidate the relationship between ASE and the curli protein, which is important for biofilm formation. Understanding this process may represent a therapeutic alternative to bacterial biofilms.