Flavan-3-ols are claimed to be responsible for the cardioprotective effects of cocoa. Alkalized cocoa powder (ALC), commonly used for many non-confectionary products, including beverages, provides less (+)-catechin, (-)-epicatechin, and procyanidins and more (-)-catechin than nonalkalized cocoa powder (NALC). This may affect the plasma appearance of monomeric flavan-3-ol stereoisomers after consumption of NALC vs. ALC. Within a randomized, crossover trial, 12 healthy nonsmokers ingested a milk-based cocoa beverage providing either NALC or ALC. Blood was collected before and within 6 h postconsumption. (+)-Catechin, (-)-catechin, and epicatechin were analyzed in plasma by HPLC as sum of free and glucuronidated metabolites. Pharmacokinetic parameters were obtained by a one-compartment model with nonlinear regression methods. For epicatechin in plasma, total area under the curve within 6 h postconsumption (AUC0-6h) and incremental AUC0-6h were additionally calculated by using the linear trapezoidal method. After consumption of NALC and ALC, (+)-catechin and (-)-catechin were mostly not detectable in plasma, in contrast to epicatechin. For epicatechin, total AUC0-6h was different between both treatments, but not incremental AUC0-6h. Most kinetic parameters were similar for both treatments, but they varied strongly between individuals. Thus, epicatechin is the main monomeric flavan-3-ol in plasma after cocoa consumption. Whether NALC should be preferred against ALC due to its higher (-)-epicatechin content remains unclear with regard to the results on incremental AUC0-6h. Future studies should investigate epicatechin metabolites in plasma for a period up to 24 h in a larger sample size, taking into account genetic polymorphisms in epicatechin metabolism and should consider all metabolites to understand inter-individual differences after cocoa intake.
Keywords: (+)-catechin; (−)-catechin; (−)-epicatechin; chiral separation; cocoa; flavan-3-ol stereoisomers; one-compartment model; pharmacokinetics; plasma appearance.