Antimicrobial activity of new coumarin derivatives.

A preliminary exploration of coumarin analogs as novel antimicrobial agents was carried out to determine the basic features of the structure responsible for the observed biological activity. The substituents ester or carboxylic acid on the coumarin ring were needed to have potent inhibitory activity against both Gram-positive and Gram-negative bacteria. The presence of phenolic hydroxyl group and/or carboxylic acid was necessary to possess higher activity against Helicobacter pylori.