INTERAKTÍVNA KONFERENCIA
MLADÝCH VEDCOV

Antioxidant, antibacterial and anti-biofilm activity of new unnatural gallotannins

Šárka Pospíšilová 1,2 Jana Hricovíniová 3 Alois Čížek 2 Josef Jampílek 1,4 Zuzana Hricovíniová 5

1Regional Centre of Advanced Technologies and Materials, Czech Advanced Technology and Research Institute, Palacky University, 783 71 Olomouc, Czech Republic
2Department of Infectious Diseases and Microbiology, Faculty of Veterinary Medicine, University of Veterinary and Pharmaceutical Sciences, 612 42 Brno, Czech Republic
3Cancer Research Institute, Biomedical Research Center, Slovak Academy of Sciences, 845 05 Bratislava, Slovak Republic
4Department of Analytical Chemistry, Faculty of Natural Sciences, Comenius University, 842 15 Bratislava, Slovak Republic
5Institute of Chemistry, Slovak Academy of Sciences, 845 38 Bratislava, Slovak Republic
sharka.pospisilova@gmail.com

Tannins represent a large sub-class of polyphenolic compounds ubiquitously present in plants. Naturally occurring gallotannins (GTs) are widely studied due to their multiple prophylactic and therapeutic effects [1]. GTs are basically composed of a central carbohydrate core that is esterified with gallic acid. The most common carbohydrate is d-glucose, although other monosaccharides are present as well. GTs are extensively studied as they exhibit diverse biological activities ranging from antioxidant, antimicrobial, antiviral, anti-inflammatory, immune-modulatory to anticancer effects [2‑4]. As a part of our ongoing studies on the synthesis of biologically important saccharides, as potential drug candidates we have synthesized a new series of GTs and evaluated their biological activities in various experimental systems. Antioxidant, antibacterial and anti-biofilm activities of structurally different GTs derived from branched-chain d-lyxose, d-ribose, l-rhamnose, d-mannose and d-fructose, together with three unnatural analogues [5] of 1,2,3,4,6-penta-O-galloyl-d-glucose (PGG) were examined and mutually compared.

Based on the experimental results obtained in this study it can be concluded that studied compounds are excellent antioxidants and radical-scavenging agents. They exhibited only moderate activity against gram-positive pathogens such as S. aureus and E. faecalis and low antimycobacterial activity. However, they were efficient inhibitors and disruptors of S. aureus biofilms in sub-MIC concentrations and interacted with quorum-sensing system in Chromobacterium violaceum. Moreover, they are non-toxic to eukaryotic cells, thus are promising candidates for further studies in developing new antimicrobial agents.

This work was financially supported by Slovak grant agency VEGA 2/0022/18 and by the Slovak Research and Development Agency APVV-17-0373.
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[3] Quideau, S., Deffieux, D., Douat-Casassus, C., Pouysegu, L. (2011). Angew. Chem. Int. Ed., 50, 586.
[4] Lin, M.-H., Chang, F.-R., Hua, M.-Y., et al. (2010). Antimicrobial Agents and Chemotherapy, 55, 1021.
[5] Hricovíniová, J., Ševčovičová, A., Hricovíniová, Z. (2020). Toxicol in Vitro 65, 104789.