FIG 1.

Proposed bacterial degradation pathway of natural estrogens. *, the deconjugated (non-CoA) metabolites were identified using UPLC-HRMS. The chemical structure of 4-norestrogenic acid, the deconjugated non-CoA structure of metabolite 5, was elucidated using NMR spectroscopy. Abbreviations: ACAD, acyl-CoA dehydrogenase; ALD, aldolase; BadH, 2-hydroxycyclohexanecarboxyl-CoA dehydrogenase; BadI, 2-ketocyclohexanecarboxyl-CoA hydrolase; ECH, enoyl-CoA hydratase; HACD, β-hydroxyacyl-CoA dehydrogenase; OAOR, 2-oxoacid oxidoreductase; THIO, thiolase.