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 inhibitory activity against the chemiluminescence of human neutrophils. By high resolution gel chromatography, a low-molecular-mass chemiluminescence inhibitor was isolated. The compound was identified as 2,4-(hydroxyphenyl)-ethanol. Half-maximum inhibition (IC50) of the chemiluminescence response of neutrophils phagocytizing opsonized zymosan or C. albicans occurred at 38.1 +/- 2.3 microM and 19.9 +/- 8.3 microM, respectively. As shown by flow cytometry, the compound protected C. albicans against phagocytic killing (IC50 = 73.8 +/- 16.9 microM). Substantially higher concentrations of the inhibitor were produced by C. albicans and C. tropicalis than by C. parapsilosis and C. glabrata, suggesting a potential role in pathogenicity ranking.