Effect of chemical modifications of tannins on their antimicrobial and antibiofilm effect against Gram-negative and Gram-positive bacteria

• Published in: Frontiers in microbiology 2023-01, Vol.13, p.987164-987164
• Main Authors: Villanueva, Xabier, Zhen, Lili, Ares, José Nunez, Vackier, Thijs, Lange, Heiko, Crestini, Claudia, Steenackers, Hans P
• Format: Article
• Language: English
• Subjects: antibiofilm activity; Escherichia coli; Microbiology; Pseudomonas aeruginosa; Salmonella Typhimurium; structure–activity relationships; tannins
• ISSN: 1664-302X; 1664-302X
• DOI: 10.3389/fmicb.2022.987164

Tannins have demonstrated antibacterial and antibiofilm activity, but there are still unknown aspects on how the chemical properties of tannins affect their biological properties. We are interested in understanding how to modulate the antibiofilm activity of tannins and in delineating the relationship between chemical determinants and antibiofilm activity. The effect of five different naturally acquired tannins and their chemical derivatives on biofilm formation and planktonic growth of Typhimurium, , and was determined in the Calgary biofilm device. Most of the unmodified tannins exhibited specific antibiofilm activity against the assayed bacteria. The chemical modifications were found to alter the antibiofilm activity level and spectrum of the tannins. A positive charge introduced by derivatization with higher amounts of ammonium groups shifted the anti-biofilm spectrum toward Gram-negative bacteria, and derivatization with lower amounts of ammonium groups and acidifying derivatization shifted the spectrum toward Gram-positive bacteria. Furthermore, the quantity of phenolic OH-groups per molecule was found to have a weak impact on the anti-biofilm activity of the tannins. We were able to modulate the antibiofilm activity of several tannins by specific chemical modifications, providing a first approach for fine tuning of their activity and antibacterial spectrum.