Membranolytic activity of detergents as studied with cell viability tests

The membranolytic activity of 12 chosen detergents upon Ehrlich ascites tumour and Chinese hamster lung cells were studied with the fluorescein diacetate and the dye exclusion tests of cell viability. It was found that all these tests give reproducible and concordant results when non-ionic detergents are used but for ionic detergents only the fluorescein diacetate test can be applied. Membranolytic activity of the detergents appeared to be uncorrelated with their capacity of membrane solubilization. Digitonin and aescin, the horse-chestnut saponin, were found to be much more toxic than sodium dodecylsulphate or Triton X-100. When the detergents with aliphatic hydrophobic residues were compared, a cationic detergent cethylmethylammonium bromide (CTAB) was more toxic than non-ionic or anionic detergents. A hydrophobic part of the aescin molecule, that is its aglycone appeared responsible for the membranolytic activity of this saponin. When the lytic activity of the tested detergents for the two tested types of cells was compared it was found that the horse-chestnut saponin substances show different toxicity for various cells. It is suggested that in the future some of the detergents can be applied for detection and quantitative monitoring of species and tissue specific differences in plasma membrane properties of animal cells.