TY - JOUR
T1 - Mode of Action of the Antimycotic Agent G2 Isolated from Alfalfa Roots
AU - Polacheck, Itzhack
AU - Levy, Mordekhai
AU - Guizie, Miriam
AU - Zehavi, Uri
AU - Naim, Michael
AU - Evron, Ruth
PY - 1991
Y1 - 1991
N2 - The mode of action of the antimycotic alfalfa root saponin, medicagenic acid 3-0-β-Dglucopyranoside (compound G2), which possesses a pronounced antifungal activity against medically important yeasts and dermatophytes, was studied in Saccharomyces cerevisiae. Compound G2 caused lethal leakage of ions out of the yeast cells. Exposure of S. cerevisiae to compound G2 resulted in a disappearance of the main sterol, ergosterol, from the cell membranes, suggesting that compound G2 was highly specific for ergosterol. Independently, chemical data indicated that compound G2 forms stable complexes with both ergosterol and cholesterol. Addition of cholesterol or ergosterol protected the cells of S. cerevisiae and several pathogenic yeasts from the inhibitory activity of compound G2 by producing a higher ratio of sterols (mainly ergosterol) to phospholipids in the membranes. The fact that an amphotericin B-resistant Candida tropicalis was susceptible to G2 suggested that its mode of action was different from that described for polyene antibiotics. This was also confirmed by the finding that 0.2 M KCl did not protect S. cerevisiae cells against ion leakage with G2, but did so with amphotericin B.
AB - The mode of action of the antimycotic alfalfa root saponin, medicagenic acid 3-0-β-Dglucopyranoside (compound G2), which possesses a pronounced antifungal activity against medically important yeasts and dermatophytes, was studied in Saccharomyces cerevisiae. Compound G2 caused lethal leakage of ions out of the yeast cells. Exposure of S. cerevisiae to compound G2 resulted in a disappearance of the main sterol, ergosterol, from the cell membranes, suggesting that compound G2 was highly specific for ergosterol. Independently, chemical data indicated that compound G2 forms stable complexes with both ergosterol and cholesterol. Addition of cholesterol or ergosterol protected the cells of S. cerevisiae and several pathogenic yeasts from the inhibitory activity of compound G2 by producing a higher ratio of sterols (mainly ergosterol) to phospholipids in the membranes. The fact that an amphotericin B-resistant Candida tropicalis was susceptible to G2 suggested that its mode of action was different from that described for polyene antibiotics. This was also confirmed by the finding that 0.2 M KCl did not protect S. cerevisiae cells against ion leakage with G2, but did so with amphotericin B.
UR - http://www.scopus.com/inward/record.url?scp=0026232661&partnerID=8YFLogxK
U2 - 10.1016/S0934-8840(11)80172-6
DO - 10.1016/S0934-8840(11)80172-6
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C2 - 1755923
AN - SCOPUS:0026232661
SN - 0934-8840
VL - 275
SP - 504
EP - 512
JO - Zentralblatt fur Bakteriologie
JF - Zentralblatt fur Bakteriologie
IS - 4
ER -