Action of surface-active substances on biological membranes. II. Hemolytic activity of nonionic surfactants.

The hemolytic action of commercially available nonionic surfactants and synthesized polyoxyethylene fatty acids and mercaptans on human erythrocytes was measured. It is shown that the hemolytic power of the detergents depends on the mutual effect of the hydrophobic and hydrophylic fragments of the agent molecule and does not depend on the hydrophile-lipophile balance of the compounds. A graphical image of the structure-activity relationship obtained in the study is similar to the one found in the literature when studying the analgesic effect of imidazoline derivatives on rats in vivo.

[Effects of non-ionogenic surface active compounds on yeast protoplasts].

The lytic effect of non-ionogenic surface active compounds (SAC), based on polyoxyethylated fatty acids and alkylphenols on the yeast protoplast cytoplasmic membranes and the extracting ability of the SAC with respect to intracellular proteins of intact yeast cells, were studied. It was shown that the lytic activity of the SAC under study depends on the overall effect of the size of their hydrophobic and hydrophylic fragments rather than on the level of the hydrophylic-lypolytic equilibrium of SAC. The absence of correlation between the lytic activity and the extracting ability of SAC is accounted for by the differences in the mechanisms of membrane degradation under the action of SAC on the protoplasts and intact cells.