The catabolites that we identified also include the above-mentioned molecular formulas. The most abundant catabolite (469.113@11.5) corresponds to demethylation. Given its abundance and comparing the peak order by retention time with this mass in the above study, we predict its formation from silybin B. We also observed other reactions, such as demethylation coupled with dihydrogenation and dihydrogenation alone, both previously mentioned in in vitro and in vivo studies. We also observed dehydroxylation alone, reported previously in the interventional study , but not in vitro . Dehydroxylation of flavonolignans may increase their hydrophobicity and improve passive diffusion across the epithelium. Even in this scenario, we anticipate that the dehydroxylated metabolites primarily originate from the most abundant constituents, silybin B and silybin A. Demethylation, dihydrogenation, dehydroxylations, and their combinations are common reactions occurring during the catabolism of dietary (poly)phenols such as ferulic acid, urolithins , anthocyanins, stilbenoids, or rutin . In the case of silymarin, we have not observed the collapse of the structure through reactions such as ring fission, as seen in the catabolism of quercetin, rutin, or flavan-3-ols as catechin. Instead, we observed the removal of peripheral substituents.