Production of Indole-3-Acetic Acid

Riboflavin-catalyzed photooxidation products of indole-3-acetic acid have an inhibitory effect on the growth of Schizosaccharomyces pombe. These products also affect E. coli and other bacteria, and inhibit the growth of tomato-root tips and the germination of pea seeds. Infrared spectroscopy has aided in the identification of these photooxidation products (Fukuyama and Moyed, 1964) as 3-hydroxymethyloxindole and 3-methyleneoxindole. Both are converted to 3-methyloxindole, which was also identified by infrared spectroscopy, and is a nontoxic substance. 

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