A simple method to detect plant based inhibitors of glycation induced protein cross-linking

Abstract

Background: Glycation induced cross-linking of proteins are associated with chronic diabetic complications. Inhibition of protein glycation is one of the therapeutic approaches to prevent the progression of diabetic complications. Objective: Objective of this study was to establish a simple method to identify medicinal plants which can inhibit glycation induced protein cross-linking. Methods: Lysozyme was incubated at 37°C up to 4 weeks with different concentrations of glucose, fructose and ribose in sodium phosphate buffer (pH 7.4). Appropriate controls and blanks were carried out. Aminoguanidine (AG) was used as the standard inhibitor. Water extracts of Bryophyllum pinnatum leaves, Coriandrum sativum seed and Murraya koenigi leaves were used as potential inhibitors. Aliquots were removed from the incubation mixtures at intervals and analyzed for the presence of AGE induced protein cross-links, using SDS-PAGE. Appearance and the intensity of high molecular weight products were compared. Results: Extent of cross-linking was dependent on the sugar concentration. Cross-linking was slowest in the presence of glucose and fastest in the presence of ribose. AG inhibited glycation induced protein cross-linking in the presence of all three sugars. B. pinnatum leaves, C. sativum seeds and M. koenigi leaves inhibited protein cross-linking in the presence of sugar. This inhibition was greater than that of AG. Conclusions: We have established a simple SDS-PAGE method to identify medicinal plants which inhibit glycation induced protein cross-linking. We also demonstrated the effectiveness of B. pinnatum leaves, C. sativum seed and M. koenigi leaves in inhibiting glycation induced protein cross-linking in vitro. DOI: http://dx.doi.org/10.3126/ajms.v6i1.10181 Asian Journal of Medical Sciences Vol.6(1) 2015 28-33

Inhibitory activities of kaempferol, galangin, carnosic acid and polydatin against glycation and α‐amylase and α‐glucosidase enzymes

“…It indicated that BSA proteins formed higher molecular weight new proteins. These protein products were cross‐linked protein induced by glycation under fructose (Perera & Ranasinghe, ). Figure a shows kaempferol had antiglycation activity, which was in a dose‐dependent manner.…”

Analysis of glycation induced protein cross-linking inhibitory effects of some antidiabetic plants and spices

“…Studies conducted to investigate protein glycation inhibitors have used expensive specialized equipments [ 9 ]. Previously we have optimized a simple SDS-PAGE method using lysozyme to detect the inhibitory effects of plant extracts on glycation induced lysozyme cross-linking [ 10 ]. Even though the glycation induced protein cross-linking inhibition by pure compounds has been studied using the SDS-PAGE method before [ 12 ], no reports were available for its application for crude plant extracts.…”

“…Being a protein with a pI of 11.35 and having 6 Lysine residues and 11 Arginine residues which are the targets of glycation, lysozyme serves as a good candidate for glycation induced protein modifications. Lysozyme showed extensive cross-linking under the conditions that increase the protein glycation such as increase in the sugar concentration, incubation period and the reactivity of the sugar [ 10 ]. With SDS-PAGE, products of glycation induced cross-linking appeared as high molecular weight bands [ 10 ].…”

“…A method developed to detect the inhibitory effects of plant extracts on protein cross-linking was used [ 10 ]. Briefly, working solutions of chicken egg lysozyme (Sigma), fructose and plant extracts were prepared using 200 mM phosphate buffer (pH 7.4) containing 0.02 % sodium azide.…”

“…In this study, the glycation induced protein cross-linking inhibitory effects of nine antidiabetic plants and three spices were evaluated, using a novel, simple, electrophoresis based method [ 10 ].…”