Beta-indoleethanol and beta-indolelactic acid production by Candida species: their antibacterial and autoantibiotic action.

Candida spp. grown in synthetic medium supplemented with l-tryptophan as sole nitrogen source produced beta-indoleethanol (beta-IEA) and beta-indolelactic acid (beta-ILA). These compounds isolated from the culture filtrates were characterized by ultraviolet, infrared, and nuclear magnetic resonance spectral studies. Using dl-[(3)H]trypotophan in the medium, labeled beta-IEA and beta-ILA were isolated. Further, beta-IEA was produced as a result incubating log-phase cells of C. albicans with beta-ILA. Both beta-IEA and beta-ILA inhibited the growth of gram-positive and -negative bacteria. Autoantibiotic action of these compounds on Candida spp. and the reversal of this inhibition were studied.