Inhibition of protein glycoxidation and advanced glycation end-product formation by barnyard millet (Echinochloa frumentacea) phenolics

Abstract

Protein glycation plays a vital role in the progression of various diabetes complications. Therefore, inhibition of protein glycation could be a key strategy to prevent these diabetic abnormalities. Evaluation of phenolic compositions and their antiglycation activity revealed that p-coumaric and chlorogenic acids were major phenolic acids in barnyard millet. These phenolics exhibited multiple antioxidant activities in various mechanisms and protected the oxidative DNA damage and hydroxyl radical-induced protein fragmentation. Millet phenolics were very effective in scavenging >78% reactive carbonyl intermediates in the reaction and protected protein thiol group oxidation. Furthermore, 68.3% inhibition of protein glycation and reduced formation of protein aggregates were also observed with millet phenolics. Besides, fluorescence intensity measurements indicated a significant decrease in advance glycated end products and protection against glycoxidation-induced protein conformational changes at 100 µg/ml phenolics. These results suggest the potential utility of barnyard millet as an ingredient in functional foods for controlling protein glycation associated diabetic complications.

Keywords: AGE; Barnyard millet; Glycoxidation; Oxidative DNA damage; Phenolics; Protein fragmentation; Protein glycation.