Spirostanol saponin permeabilization of Candida albicans cells resulte
d in phosphate (Pi) leakage from these cells. Pre-incubation of C. alb
icans suspension cultures with ergosterol or cycloiridals inhibited Pi
leakage when cells were subjected to saponins. Saponins were shown to
precipitate ergosterol but not cycloiridals. Inhibition of Pi leakage
in the presence of cycloiridals could thus be due to their incorporat
ion into cell membranes. Cycloiridals, which were previously shown to
modify fluidity parameters in artificial phospholipid bilayers, seem i
n vivo to have a protective effect on membranes against surfactant (sa
ponin) injury. Copyright (C) 1997 Elsevier Science Ltd.