Flavonoids from Polyalthia longifolia prevents advanced glycation end products formation and protein oxidation aligned with fructose-induced protein glycation.

ABSTRACT

Advanced glycation end products (AGEs) are reactive chemical entities formed by non-enzymatic reaction between reducing sugars and amino group of proteins. Enhanced accumulation of AGEs and associated protein oxidation contribute to pathogenesis of diabetes-associated complications. Here, we evaluated the inhibitory activity of flavonoid compounds isolated from the leaves of Polyalthia longifolia on formation of AGEs and protein oxidation. Antiglycation activity was determined by measuring the formation of AGE fluorescence intensity, Nε-(carboxymethyl) lysine, and level of fructosamine. Protein oxidation was examined using levels of protein carbonyls and thiol group. Compounds significantly (p < 0.001) restricted the formation of fluorescent AGEs in fructose- BSA and methylglyoxal-BSA systems. Furthermore, there was a decrease in levels of fructosamine and protein carbonyls, and elevation in level of thiol group in fructose-BSA in presence of flavonoids. In summary, flavonoids from Polyalthia longifolia inhibit fructose-mediated protein glycation and oxidation, and can be potential agent for preventing AGE-mediated diabetic complications.