Analysis of distribution and pharmacokinetics of litchi pericarp procyanidins in rat plasma and organs by using liquid chromatography-tandem mass spectrometry

Litchi pericarp procyanidins (LPP), which were mainly A-types, inhibit cardiovascular disease in vivo significantly. In order to know the pharmacokinetics of LPP, procyanidin (PC) metabolites were examined in various organs of rats at different time points after LPP ingestion. Plasma, liver, kidneys, spleen, brain, together with gastrointestinal (GI) tract of rats were collected over a 24-h period. The PC metabolic product residuals were extracted and identified by HPLC-Trap-MS-MS and LC/Q-trap-MS analyses. According to the data, there were eight PC metabolites with glucuronide, sulfate, and methyl ethers detected, in which brain was the first target of (-)-epicatechin, A-type dimers, and trimer, reaching their maximum values at 0.5 h post-administration. Liver was the major organ for glucuronidated, sulfated, and methylated transform during PC metabolism. GI tract was the primary system to recover PCs. Furthermore, all the litchi pericarp flavan-3-ols and PCs were eliminated from the stomach and GI tract 24 h after administration. (-)-Epicatechin conjugates, which were detected in plasma and brain as the major PC metabolites, demonstrating that flavan-3-ols and their metabolic products can cross the blood-brain barrier. And the results were also considerably helpful for us to know that A-type PCs are bioavailable in body.