Absorption and urinary excretion of A-type procyanidin oligomers from Litchi chinensis pericarp in rats by selected ion monitoring liquid chromatography–mass spectrometry

Intervention studies with A-type oligomeric procyanidins from litchi (Litchi chinensis) pericarp (LPOPC) suggested its protective effect against cardiovascular diseases. However, there is no consensus on the absorption and metabolism of LPOPC. It was demonstrated that the main components in LPOPC were (−)-epicatechin, A-type procyanidin dimers, trimers and tetramers. Rats were orally administered different levels of LPOPC (150 and 300 mg/kg bw), the procyanidins and their microbial metabolites in urine were identified by HPLC–MS/MS analysis 18 h post-administration. Data indicated that seven aromatic acid metabolites excreted were significantly increased by 300 mg/kg bw of LPOPC (P < 0.01). However, only (−)-epicatechin and its methylated derivatives were detected in rat plasma 1 h after 300 mg/kg bw of LPOPC administration. The total EC content absorbed in plasma was only 2.54 ± 0.53 μmol/L, indicating that the biological properties of LPOPC should be probably explained by its microbial degraded phenolic acids.