Degradation of DOPA by Intestinal Microorganisms in Vitro

The degradation of L‐DOPA, 14C‐DL‐DOPA and possible phenolic metabolites in anaerobic incubates of rat caecal contents was studied by gas chromatography, thin‐layer chromatography and radiochromatogram scanning. The main pathway of DOPA metabolism involved degradation to 3,4‐dihydroxyphenylacetic acid which underwent decarboxylation or dehydroxylation to yield 4‐methylcatechol or 3‐hydroxyphenylacetic acid, respectively. The latter compound was decarboxylated to meta‐cresol in a few of the incubates. 3‐Hydroxy‐phenylpropionic acid was an additional metabolite which was apparently further metabolized afterprolonged incubation. The relevance of these findings to DOPA metabolism in the intestinal lumen in vivo is briefly discussed.