EFFECTS OF SAPONINS AND GLYCOALKALOIDS ON THE PERMEABILITY AND VIABILITY OF MAMMALIAN INTESTINAL-CELLS AND ON THE INTEGRITY OF TISSUE PREPARATIONS IN-VITRO

The effects of potato and tomato glycoalkaloids and a saponin mixture from Gypsophila were investigated in cytotoxicity studies (neutral red uptake, mitochondrial MTT reduction and release of lactate dehydrogen ase), using cultured cell lines of rat and human intestinal mucosal ep ithelium. Experiments to assess the effects of these compounds on the integrity of the intestinal epithelium were also carried out using pre parations of isolated rat jejunum in vitro. By investigating the effec t of these compounds on cultured cells and on intestinal tissue prepar ations, changes in membrane integrity, as evidenced by lactate dehydro genase leakage in cell culture, could be confirmed in a system more re levant to the whole gut. Of the compounds tested, alpha-tomatine was c onsistently the most potent in all tests, and indications of a synergi stic effect on membrane depolarization were observed between alpha-cha conine and alpha-solanine at total glycoalkaloid concentrations of les s than 1 mM (< 0.86 mg/ml), with an optimum when the former comprised 25% of the mixture. An increase in the apparent permeability of the br ush border was observed at sublethal concentrations of the compounds, and this may have important implications with respect to enhanced upta ke of macromolecules, such as allergens, whose passage through the epi thelium is normally somewhat restricted. Copyright (C) 1996 Elsevier S cience Ltd.