Short communicationStability of polyphenols epigallocatechin gallate and pentagalloyl glucose in a simulated digestive system

Polyphenols found in foods and beverages are under intense scrutiny for their potential beneficial effects on human health. We examined the stability of two bioactive polyphenols, epigallocatechin-O-gallate (EGCg) and 1,2,3,4,6-penta-O-galloyl-β-D-glucopyranose (PGG), in a model digestive system at low oxygen tension with and without added digestive components and foods. Both compounds were stable at pH values of 5-6 and below, indicating gastric stability. Both compounds decomposed at pH 7.0. PGG was stabilized in a model system containing pepsin, pancreatin, bile and lipase, and/or baby food, but was not stabilized by dry cereal. EGCg was not stabilized by the addition of any biomolecule. The effects of polyphenols on human health should be evaluated in the context of their stability in the digestive tract with and without added digestive components and/or food.

► Pentagalloyl glucose (PGG) & epigallocatechin gallate (EGCg) are food polyphenols. ► Polyphenols PGG & EGCg are stable to in vitro digestion at pH < 6 ► Polyphenols PGG & EGCg are destroyed during low oxygen, in vitro digestion at pH 7 ► Polyphenol PGG is protected from destruction during digestion by added biomolecules ► Polyphenol EGCg is not protected during digestion by added biomolecules.