Prevention of non-enzymic glycation of proteins by dietary agents: prospects for alleviating diabetic complications

Abstract

The accumulation of advanced glycation endproducts (AGE) due to non-enzymic glycation of proteins has been implicated in several pathophysiologies associated with ageing and diabetes. The formation of AGE is accelerated in hyperglycaemic conditions, which alter the structure and function of long-lived proteins. Thus inhibition of the formation of AGE is believed to play a role in the prevention of diabetic complications. In the present study we evaluated the antiglycating effect of aqueous extracts of various plant-based foods. The effect of aqueous extracts of these agents in terms of their ability to prevent the accumulation of AGE due to fructose-mediated in vitro glycation of eye lens soluble proteins was investigated. The degree of protein glycation in the absence and presence of dietary extracts was assessed by different complementary methods, i.e. non-tryptophan AGE fluorescence, AGE-induced cross-linking by SDS-PAGE and glyco-oxidative damage by carbonyl assay. Five out of the seventeen agents tested showed significant inhibitory potential against in vitro protein glycation in a dose-dependent manner. Prominent among them were ginger, cumin, cinnamon, black pepper and green tea, which inhibited in vitro AGE formation to lens proteins 40-90 % at 1·0 mg/ml concentration. Assessing their potential to reduce the amount of glycated protein using boronate affinity chromatography and also their ability to prevent the formation of specific antigenic-AGE structures by immunodetection further substantiated the importance of ginger, cumin and cinnamon in reducing AGE burden. These findings indicate the potential of some dietary components to prevent and/or inhibit protein glycation. Thus these dietary agents may be able to be exploited for controlling AGE-mediated diabetic pathological conditions in vivo.

Determination of in vitro antidiabetic effects of Zingiber officinale Roscoe

“…Hence the extracts showed a dose-dependent inhibition of protein glycation. Previously, 63% glycation inhibition by ginger at the concentration of 1.0 mg/mL was reported (Saraswat et al, 2009).…”

“…The NEG inhibitory activity of ginger depends, at least in part, on its ability to trap reactive carbonyl intermediates in NEG/AGE formation, thereby inhibiting the chemical modification of proteins. In terms of preventing protein and sugar cross-links, the aqueous extracts of ginger showed 30-80% reductions (Saraswat et al, 2009).…”

“…Although several studies have mentioned antidiabetic activity of Zingiber officinale (Grover et al, 2002;Akhani et al, 2005;Kelble, 2005;Al-Amin et al, 2006;Büyükbalci, Sedef, 2008;Islam, Choi, 2008;Abd-Elraheem et al, 2009;Saraswat et al, 2009;Ogbera et al, 2010;Saraswat et al, 2010;Madkor et al, 2011;Ramudu et al, 2011;Rani et al, 2011), no data is available on protein glycation and glucose absorption inhibitory potential of native Zingiber officinale rhizomes at national level. The present study was undertaken to investigate the antidiabetic effects of Zingiber officinale in terms of glucose diffusion and glycation inhibition.…”

Aqueous extract of some indigenous medicinal plants inhibits glycation at multiple stages and protects erythrocytes from oxidative damage–an in vitro study

“…indica (leaf), E. officinalis (fruit) and S. cumini (seed) and T. bellirica (fruit) were procured from an herbal store (Ambadas Vanaushadhalaya, Pune) in the powder form. Aqueous plant extracts (1 mg/ml) were prepared in double distilled water as per method of Saraswat et al (2009) with some modification. Extracts were then kept on shaker (150 rpm) for 3 h, followed by centrifugation (3,000 rpm, 10 min) (SuperspinR-V/FM, Plasto craft, India).…”

Pharmacognostical and Phytochemical Analysis of Triphaladi Ghana-Vati - An Ayurvedic Polyherbal Formulation for Senile Immature Cataract

“…[10] ,Anti-AGE properties (AntiAdvanced glycation end products) of Shunthi and Tulasi. [11] , Hypoglycaemic, immunomodulatory, anti-oxidant effect of Triphala, Immunomodulatory and Rejuvenating aspects of Gudoochi, Gokshura and Amalaki. [12] free radicals scavenging action of …”