Abstract:
Chronic hyperglycemia causes non-enzymatic glycation between reducing sugars and amino groups of proteins, resulting in production of advanced glycation end products (AGEs). Strong evidences reveal that AGEs are important factors responsible for both microvascular and macrovascular diabetic complications. Moringa oleifera, one of the most medicinal plants that are commonly used in Thailand, has been shown to have the favorable effects in the prevention or treatment of diabetes through various mechanisms of action. However, anti-glycation property of Moringa oleifera leaf extract in vitro has not been investigated. Therefore, the aim of this study was to examine the ability of Moringa oleifera aqueous leaf extract (MOE) on protein glycation by incubated bovine serum albumin (BSA) in 0.1 M phosphate buffer saline (pH 7.4) with 0.5 M glucose, 0.5 M fructose or 1 mM methylglyoxal with or without MOE (0.5-2.0 mg/mL) at 37ºC. It was found that MOE contained polyphenol and flavonoids including ferulic acid (225.54 ɥg), rutin (0.09 ɥg), quercetin (0.41 ɥg), and keamferol (0.15 ɥg). Inhibitory effects of MOE on protein glycation was demonstrated by a significant dose-dependent reduction in the formation of fluorescence and non-fluorescence AGEs (Ne-(carboxymethyl) lysine (CML)), with concomitant a marked decrease in fructosamine level. In addition, MOE also inhibited the cross-linking of protein by reducing β-amyloid structure formation (P<0.05). Moreover, MOE prevented the oxidation of protein manifested by reducing protein carbonyl and increasing protein thiol in a dose-dependent manner (P<0.05). In conclusion, our findings indicate the possibility of using MOE as the therapeutic agent for preventing glycation-related diabetic complications
