Bioavailability of anthocyanidin-3-glucosides following consumption of red wine and red grape juice

Pharmacokinetic parameters and the bioavailability of several dietary anthocyanins following consumption of red wine and red grape juice were compared in nine healthy volunteers. They were given a single oral dose of either 400 mL of red wine (279.6 mg total anthocyanins) or 400 mL of red grape juice (283.5 mg total anthocyanins). Within 7 h, the urinary excretion of total anthocyanins was 0.23 and 0.18% of the administered dose following red grape juice and red wine ingestion, respectively. Pharmacokinetic parameters derived from plasma and urine concentrations exhibited higher variability after ingestion of red grape juice. Compared to red grape juice anthocyanins, the relative bioavailability of red wine anthocyanins was calculated to be 65.7, 61.3, 61.9, 291.5, 57.1, and 76.3% for the glucosides of cyanidin, delphinidin, malvidin, peonidin, petunidin, and its sum (referred to as total anthocyanins), respectively. Bioequivalence was established for none of the anthocyanins. On a low level, urinary excretion of anthocyanins was fast, and the excretion rates seem to exhibit monoexponential characteristics over time after ingestion of both red grape juice and red wine. Due to low bioavailability, any significant contribution of anthocyanins to health protecting properties of red wine or red grape juice seems questionable, but the clinical relevance of these findings awaits further investigation.Key words: pharmacokinetics, anthocyanins, glycosides, bioavailability, humans.