Guaraná (Paullinia cupana) catechins and procyanidins: Gastrointestinal/colonic bioaccessibility, Caco-2 cell permeability and the impact of macronutrients

Guaraná (Paullinia cupana) seeds are rich in flavan-3-ols (catechins) and reduce oxidative stress in humans. We determined the concentration and in vitro bioaccessibility of catechins in guaraná seeds from two geographical origins, and measured their Caco-2 permeability. The effect of macronutrients on catechins’ bioaccessibility and Caco-2 permeability was also evaluated. Guaraná seeds from southern Bahia and Maués contained, respectively, 30.0 and 26.8 mg catechin/g, 20.2 and 20.0 mg epicatechin/g, 3.7 and 3.8 mg procyanidin B1/g, and 3.3 and 4.9 mg procyanidin B2/g. Bioaccessibility ranged between 65 and 95% for catechin monomers and 50–140% for dimers. Casein inhibited bioaccessibility of catechin dimers, while vegetable oil improved bioaccessibility of total procyanidins. Guaraná catechin monomers and dimers were able to permeate through Caco-2 cell monolayers (Papp 0.31–0.35 × 10−6 cm/s) without effect from co-digested macronutrients. Guaraná seeds are a source of highly bioaccessible catechins, which can permeate the intestinal epithelium with negligible effect from macronutrients.