Epicatechin in human plasma: In vivo determination and effect of chocolateconsumption on plasma oxidation status

Diets that are rich in plant foods have been associated with a decreased ri sk for specific disease processes and certain chronic diseases. In addition to essential macronutrients and micronutrients, the flavonoids in a variet y of plant foods may have health-enhancing properties. Chocolate is a food that is known to be rich in the flavan-3-ol epicatechin and procyanidin oli gomers. However, the bioavailability and the biological effects of the choc olate flavonoids are poorly understood. To begin to address these issues, w e developed a method based on HPLC coupled with electrochemical (coulometri c) detection to determine the physiological levels of epicatechin, catechin and epicatechin dimers. This method allows for the determination of 20 pg (69 fmol) of epicatechin, which translates to plasma concentrations as low as I nmol/L. We next evaluated the absorption of epicatechin, from an 80-g semisweet chocolate (procyanidin-rich chocolate) bolus. By 2 h after ingest ion, there was ale-fold increase in plasma epicatechin, from 22 to 257 nmol /L (P < 0.01). Consistent with the antioxidant properties of epicatechin, w ithin the same 2-h period, there was a significant increase of 31% in plasm a total antioxidant capacity (P < 0.04) and a decrease of 40% in plasma 2-t hiobarbituric acid reactive substances (P < 0.01). Plasma epicatechin and p lasma antioxidant capacity approached baseline values by 6 h after ingestio n. These results show that it is possible to determine basal levels of epic atechin in plasma. The data support the concept that the consumption of cho colate can result in significant increases in plasma epicatechin concentrat ions and decreases in plasma baseline oxidation products.