Evaluation of the susceptibility of planktonic cells and bacterial biofilms to Sarcomphalus joazeiro extracts

Bacterial biofilms are structured communities of microorganisms embedded in an extracellular matrix, which confer high resistance to antibiotics and complicate the treatment of infections. In this context, the search for new strategies to control bacterial resistance becomes urgent. This study aimed to evaluate the susceptibility of planktonic cells and bacterial biofilms to the hydroethanolic extracts of the bark (HEBSJ) and leaves (HELSJ) of Sarcomphalus joazeiro , as well as to perform their chemical characterization. The extracts were obtained by cold maceration and analyzed using UPLC-ESI-QToF-MS E . Antibacterial activity and biofilm formation/inhibition assays were conducted in 96-well microdilution plates, with quantification performed using the crystal violet method and absorbance readings taken at 570 nm. All tests were performed in triplicate. Chemical analysis revealed the presence of flavonoids, organic acids, and saponins. Regarding biofilm-forming capacity, Staphylococcus aureus and Staphylococcus epidermidis were classified as strong biofilm producers; Enterococcus faecalis , Streptococcus mutans , and Pseudomonas aeruginosa showed moderate biofilm formation, while Escherichia coli was classified as a non-biofilm-producing strain. HELSJ exhibited inhibitory activity only against P. aeruginosa , while it appeared to promote biofilm formation in the remaining strains. In contrast, HEBSJ demonstrated inhibitory activity in all analyzed strains at least at one tested concentration, including complete inhibition of E. faecalis biofilm, outperforming chlorhexidine. In conclusion, the bark extract (HEBSJ) showed superior and consistent antibiofilm activity across all tested strains, with significant results compared to the leaf extract (HELSJ), which exhibited limited efficacy. These findings reinforce the need for further studies to elucidate the mechanisms of action involved and support the development of novel phytotherapeutic agents for the treatment of biofilm-associated infections. • The chemical characterization UPLC-ESI-QToF-MSE revealed the presence of flavonoids, saponins, and organic acids. • HEBSJ showed better biofilm inhibition results than HELSJ • HEBSJ showed complete inhibition of Enterococcus faecalis biofilm.