Antibacterial Biofilms of Chitosan Incorporated with the Ethanolic Extract of the Stem Bark of Libidibia ferrea and Its Fractions.

The high mortality rate from microbial infections underscores the need to discover new antimicrobials. This work produced antibacterial Chitosan biofilms with and without the incorporation of the ethanolic extract of Libidibia ferrea stem bark and its ethyl acetate and aqueous fractions. The extract and fractions were subjected to FTIR and 1H NMR analysis. The biofilms were characterized by FTIR, scanning electron microscopy, thermogravimetry, and differential scanning calorimetry analysis. The 1H NMR and FTIR data, as well as the colorimetric quantification of total phenolics, demonstrated the presence of phenolic compounds. Staphylococcus aureus and Bacillus cereus were the most susceptible bacteria for Chitosan/L. ferrea biofilms and fractions (growth inhibition zones values in the range of 10.8 ± 0.1 to 14.0 ± 0.1 mm, and minimum inhibitory or bactericidal concentration, MIC or MBC values of the fractions were in the range of 125 to 250 µg mL-1. Only the fractions inhibited Pseudomonas aeruginosa (MIC = 250 µg mL-1). Chitosan/L. ferrea biofilms exhibited efficient interactions between chitosan functional groups and secondary metabolites, good thermal stability, and increased rigidity in mechanical tests. This study reinforces the pharmacological potential of biodegradable Chitosan/L. ferrea biofilms as antibacterial agents biofilms.