Antibacterial properties of ion channel forming fatty acid oligo (ethylene glycol) esters

Fatty acid oligo (ethylene glycol) esters (1a–e) have been characterized as cation channel forming compounds. The largest ion channel forming efficiency of 1a–e was found in 1d. Thence, a comparison of 1d with the natural ion channel forming peptide gramicidin D by fluorescence emission measurements was aimed at. It was shown that ionic channels formed by 1d allow at higher concentrations more potassium ions per time unit to diffuse across the lipid membrane than channels formed by gramicidin D. 1a–e were also assumed to be able to insert into cytoplasmic membranes of bacterial cells. This incorporation would lead to the breakdown of the electrochemical potential across the membrane and consequently to cell death. Therefore, the possibility of an antibacterial activity of 1a–e was taken into consideration. Agar well diffusion tests confirmed this assumption by exhibiting growth inhibition with Gram-positive organisms.