The aqueous medium-dimethylsulfoxide conundrum in biological studies

A series of straight and branched chain pyrogallol[4]arenes was studied and found to be essentially nontoxic to two strains of E. coli. An apparent enhancement of potency observed for kanamycin against E. coli was found to be due to the presence of DMSO in the growth media. Quantitative studies are presented that assay the effect of DMSO concentration on the apparent potency of kanamycin against E. coli.