Phytochemicals from berries and grapes inhibited the formation of advanced glycation end‐products by scavenging reactive carbonyls

Phenolic phytochemicals were extracted from blueberries, blackberries, strawberries, raspberries, cranberries, and Noble muscadine grapes. These extracts were purified to remove free sugars. Blueberry extract was separated into five fractions using a Sephadex LH‐20 column. Berry extracts and fractions significantly inhibited AGEs generation in (bovine serum albumin) BSA‐fructose, BSA‐methylglyoxal, and arginine‐methylglyoxal models, respectively. Their capacity to scavenge methylglyoxal suggested carbonyl scavenging as a major mechanism of protein glycation inhibition. Procyanidins were detected in all berry extracts and blueberry subfractions and were deduced to be one class of active compounds. (+)‐Catechin, constituent unit of procyanidins, was used as a model compound to react with glyoxal and methylglyoxal. Five catechin‐carbonyl adducts were detected and their structures were tentatively identified using HPLC‐ESI‐MSn. Results in this study suggested that sugar‐free phytochemicals extracted from berries were effective carbonyl scavengers and protein glycation inhibitors. These phytochemicals could be beneficial to prevent AGE‐related chronic diseases.

Research highlights
► Phenolic phytochemicals from berries and grapes inhibited protein glycation.
► Berry and grape phytochemicals scavenged reactive carbonyls.
► Catechin reacted with glycoxal and methylglyoxal and formed various adducts.