Inhibition studies of bacterial α-carbonic anhydrases with phenols

The alpha-class carbonic anhydrases (CAs, EC 4.2.1.1) from the bacterial pathogens Neisseria gonorrhoeae (NgCA alpha) and Vibrio cholerae (VchCA alpha) were investigated for their inhibition by a panel of phenols and phenolic acids. Mono-, di- and tri-substituted phenols incorporating additional hydroxyl/hydroxymethyl, amino, acetamido, carboxyl, halogeno and carboxyethenyl moieties were included in the study. The best NgCA alpha inhibitrs were phenol, 3-aminophenol, 4-hydroxy-benzylalcohol, 3-amino-4-chlorophenol and paracetamol, with K-I values of 0.6-1.7 mu M. The most effective VchCA alpha inhibitrs were phenol, 3-amino-4-chlorophenol and 4-hydroxy-benzyl-alcohol, with K-I values of 0.7-1.2 mu M. Small changes in the phenol scaffold led to drastic effects on the bacterial CA inhibitory activity. This class of underinvestigated bacterial CA inhibitors may thus lead to effective compounds for fighting drug resistant bacteria.