Bioavailability of epicatechin after consumption of grape seed extract in humans

Abstract

Diets that are rich in plant foods have been associated with a decreased risk for specific disease processes and certain chronic diseases. In addition to essential macronutrients and micronutrients, the flavonoids in a variety of plant foods may have health-enhancing properties. Grape Seed Extract (GSE) is a common supplement that is known to be rich in the flavan-3-ol epicatechin and procyanidin oligomers. However, the bioavailability and the biological effects of the grape seed extract flavonoids are poorly understood. To begin to address these issues, we developed a method based on LC-MS detection to determine the physiological levels of epicatechin and catechin. This method allows for the determination of epicatechin in plasma at concentrations as low as 1 ng/mL. We next evaluated the absorption of epicatechin, from 1-g grape seed extract taken orally in capsule form. By 2 h after ingestion, plasma epicatechin increased from an undetectable amount to 172 ng/ml (P, 0.001). Consistent with the antioxidant properties of epicatechin, within three hours, there was a significant 25% increase in plasma antioxidant reserve (P, 0.05). The data support the concept that the consumption of grape seed extract can result in significant increases in plasma epicatechin concentrations as well as an increase in plasma antioxidant reserve.