(+)-Catechin is more bioavailable than (−)-catechin: Relevance to the bioavailability of catechin from cocoa

Catechin is a flavonoid present in fruits, wine and cocoa products. Most foods contain the (+)-enantiomer of catechin but chocolate mainly contains ( − )-catechin, in addition to its major flavanol, ( − )-epicatechin. Previous studies have shown poor bioavailability of catechin when consumed in chocolate. We compared the absorption of ( − ) and (+)-catechin after in situ perfusion of 10, 30 or 50 μmol/l of each catechin enantiomer in the jejunum and ileum in the rat. We also assayed 23 samples of chocolate for (+) and ( − )-catechin. Samples were analyzed using HPLC with a Cyclobond I-2000 RSP chiral column. At all concentrations studied, the intestinal absorption of ( − )-catechin was lower than the intestinal absorption of (+)-catechin (p < 0.01). Plasma concentrations of ( − )-catechin were significantly reduced compared to (+)-catechin (p < 0.05). The mean concentration of ( − )-catechin in chocolate was 218 ± 126 mg/kg compared to 25 ± 15 mg/kg (+)-catechin. Our findings provide an explanation for the poor bioavailability of catechin when consumed in chocolate or other cocoa containing products.