Natural Compounds as Inhibitors of Tyrosyl-tRNA Synthetase.

Tyrosyl-tRNA synthetases (TyrRSs) as essential enzymes for all living organisms are good candidates for therapeutic target in the prevention and therapy of microbial infection. We examined the effect of various polyphenols, alkaloids, and terpenes-secondary metabolites produced by higher plants showing many beneficial properties for the human organism, on bacterial aminoacylation reaction. The most potent inhibitors of Escherichia coli TyrRS are epigallocatechin gallate, acacetin, kaempferide, and chrysin, whereas the enzymes from Staphylococcus aureus and Pseudomonas aeruginosa are inhibited mainly by acacetin and chrysin. Most of them act as competitive inhibitors. Structure-activity relationship showed that the most potent flavonoid inhibitors contain hydroxyl group at position 5 and 7 of A ring and OCH3 group at position 4' of B ring.