Bioavailability of cranberry bean hydroalcoholic extract and its inhibitory effect against starch hydrolysis following in vitro gastrointestinal digestion

Abstract This study used a simulated in vitro gastrointestinal digestion procedure to assess the bioavailability of a freeze-dried cranberry bean hydroalcoholic extract (polyphenol content of 28.73 mg g − 1 ). The amount of polyphenols in 200 mg of cranberry bean extract increased from 5.73 (non-digested original) to 11.39 mg following gastric digestion, but decreased to 6.05 mg during intestinal digestion. When cranberry bean extract was accompanied with starch for the digestion tests, the added cranberry bean extract exhibited a potent inhibitory effect against glucose release during simulated intestinal digestion, with IC 50 values of 472 mg cranberry bean extract or 13 mg polyphenols. A significant decrease in polyphenols was observed for the sample collected from dialysis phase, with only 11% of non-digested original polyphenols permeating through the dialysis membrane (0.63 mg) and preserving an inhibitory effect against α-glucosidase to some extent. Therefore, polyphenol-rich cranberry bean extract may be used to manage postprandial hyperglycemia.