2,4-(hydroxyphenyl)-ethanol, an antioxidative agent produced by Candida spp., impairs neutrophilic yeast killing in vitro

Culture supernatants of Candida albicans were examined for factors with inh ibitory activity against the chemiluminescence of human neutrophils. By hig h resolution gel chromatography, a low-molecular-mass chemiluminescence inh ibitor was isolated. The compound was identified as 2,4-(hydroxyphenyl)-eth anol. Half-maximum inhibition (IC50) of the chemiluminescence response of n eutrophils phagocytizing opsonized zymosan or C. albicans occurred at 38.1 +/-2.3 mu M and 19.9 +/- 8.3 mu M: respectively. As shown by flow cytometry , the compound protected C. albicans against phagocytic killing (IC50 = 73. 8 +/- 16.9 mu M). Substantially higher concentrations of the inhibitor were produced by C, albicans and C. tropicalis than by C. parapsilosis and C. g labrata, suggesting a potential role in pathogenicity ranking. (C) 1999 Fed eration of European Microbiological Societies. Published by Elsevier Scienc e B.V. All rights reserved.