The catabolites were further investigated by classifying their relative intensity based on their AUC value over 24 h. To simplify this article, we have named the catabolites we found according to their m/z value and retention time, connected by '@'. The most abundant catabolite was a final catabolite with m/z 469.113 eluting at 11.5 min (469.113@11.5); this is likely to be a demethylation product of the most abundant silybin B, which is formed by the loss of 14.016 m/z. The other four metabolites with m/z 469.113 are likely to be demethylation products of less abundant silymarin flavonolignan isomers. In addition, the remaining final catabolites were likely formed by dihydroxylation, demethylation or hydrogenation. Demethylation in combination with other transformations is mainly associated with the early catabolites, whereas the late catabolites are mainly the result of dehydroxylation. A comprehensive list of catabolites and their predicted chemical changes can be found in Table .