New paper published in Molecular Nutrition and Food Research

Grape-seed phenolic compounds were recently shown as satiating agents when administered as a whole grape-seed phenolic extract (GSPE) in rats, despite its administration also produces a paradoxical short-term increase in the plasma levels of the orexigenic hormone ghrelin. The pure phenolic compounds of GSPE present different effects on ghrelin secretion when studied in ghrelin-producing cells. Monomeric flavanols stimulate ghrelin release via activation of bitter taste receptors, while oligomeric flavanols and gallic acid act conversely inhibiting ghrelin release. Gallic acid also reduce the ghrelin release of rat intestinal segments and produced a short-term decrease in plasma ghrelin in rats. When the effects of GSPE were further studied in rats, we observed that GSPE produces a long-term decrease in plasma ghrelin, ghrelin release from intestinal segments and ghrelin synthesis in stomach, which correlated with a diminished food intake and body weight gain. Thus, gallic acid and the oligomeric flavanols of GSPE play an important role in the satiating effects of GSPE due to its ghrelin-inhibiting properties.