Cyclodextrin derivatives that exhibit <i>Enterococcus</i> -specific antibacterial properties through the accumulation of guanidino and indole groups

In light of the growing challenge posed by drug resistance, the focus of our research has been on the development of novel antibacterial substances. The approach involves the attachment of antibacterial functional groups to oligosaccharide, known as cyclodextrin, utilising antimicrobial peptides possessing hydrophobic groups and cationic groups as a model system. The cyclodextrin derivative, which contains seven pairs of indole rings and guanidino groups, was synthesised and exhibited potent antibacterial properties that were selective for <i>Enterococcus faecalis</i>. Conversely, a compound comprising a single set of functional groups was selectively antibacterial against <i>Staphylococcus aureus</i>. These were unique phenomena in that they were completely different from the peptides containing indole and guanidino groups and the previously reported antibacterial cyclodextrins modified with alkylamino groups that showed a broad antibacterial spectrum. The results will lead to the discovery of new chemical compounds (or functional groups) those will demonstrate specific antibacterial properties for pathogens and may be useful in the fields of cyclodextrin chemistry and development of antibacterial drugs and materials, particularly in the fight against multidrug-resistant pathogens.