The profiling and identification of the metabolites of (+)‐catechin and study on their distribution in rats by HPLC‐DAD‐ESI‐IT‐TOF‐MS ⁿ technique

(+)‐Catechin, a potential beneficial compound to human health, is widely distributed in plants and foods. A high‐performance liquid chromatography with diode array detector and combined with electrospray ionization ion trap time‐of‐flight multistage mass spectrometry method was applied to profile and identify the metabolites of (+)‐catechin in rats and to study the distribution of these metabolites in rat organs for the first time. In total, 51 phase II metabolites (44 new) and three phase I metabolites were tentatively identified, comprising 16 (+)‐catechin conjugates, 14 diarylpropan‐2‐ol metabolites, 6 phenyl valerolactone metabolites and 18 aromatic acid metabolites. Further, 19 phase II metabolites were new compounds. The in vivo metabolic reactions of (+)‐catechin in rats were found to be ring‐cleavage, sulfation, glucuronidation, methylation, dehydroxylation and dehydrogenation. The numbers of detected metabolites in urine, plasma, small intestine, kidney, liver, lung, heart, brain and spleen were 53, 23, 27, 9, 7, 5, 3, 2 and 1, respectively. This indicated that small intestine, kidney and liver were the major organs for the distribution of (+)‐catechin metabolites. In addition, eight metabolites were found to possess bioactivities according to literature. These results are very helpful for better comprehension of the in vivo metabolism of (+)‐catechin and its pharmacological actions, and also can give strong indications on the effective forms of (+)‐catechin in vivo. Copyright © 2013 John Wiley & Sons, Ltd.