Acriflavine is an
antiseptic, fungicide, and effective agent against
parasitic infections, inducing petite mutation in the yeast Saccharomyces cerevisiae and kinetoplast loss in Trypanosomidae. Here we showed that
acriflavine caused both apoptosis and
necrosis in the yeast Candida utilis. Cells were cultured in minimal medium, with 1.5%
ethanol as substrate, in the presence of 30-180 micromol/L
acriflavine. Fluorescence measurements showed a linear concentration-dependence flux of the
drug into the cells.
Acriflavine induced a decrease in cell number, an increase in
trypan blue-positive cells, and a decrease in cell viability. Cells cultured in the presence of
acriflavine showed an alteration in their respiratory control ratio and a decrease in their
cytochrome content. Fluorescence microscopy, after
acridine orange staining, revealed the presence of apoptotic cells in cultures conducted in the presence of
acriflavine. Electron microscopy of cells grown in the presence of
acriflavine showed apoptotic cells exhibiting
chromatin condensation, cytoplasmic lysis, but reasonably well-preserved mitochondria, whereas necrotic cells showed no distinctive intracellular organelles. Data showed that
acriflavine caused both apoptosis and
necrosis. Moreover,
acriflavine induced oxidative phosphorylation uncoupling. Generally, apoptosis is considered to be mediated either by a change in mitochondrial permeability and
cytochrome c release or by plasma membrane
death receptor activation. The outer mitochondrial membrane permeability to
cytochrome c, with efflux of
protons to the cytosol and cytoplasmic acidification, produced a collapse in the electrochemical
proton gradient, a decrease in
ATP synthesis, and subsequent cytolysis leading to apoptosis and
necrosis.