Inhibition of protein glycation and advanced glycation end products by ascorbic acid

2012 ◽  
Vol 11 (51) ◽  
Author(s):  
Hira Zafar,
2021 ◽  
Author(s):  
Akio Nakamura ◽  
Ritsuko Kawahrada

Protein glycation is the random, nonenzymatic reaction of sugar and protein induced by diabetes and ageing; this process is quite different from glycosylation mediated by the enzymatic reactions catalysed by glycosyltransferases. Schiff bases form advanced glycation end products (AGEs) via intermediates, such as Amadori compounds. Although these AGEs form various molecular species, only a few of their structures have been determined. AGEs bind to different AGE receptors on the cell membrane and transmit signals to the cell. Signal transduction via the receptor of AGEs produces reactive oxygen species in cells, and oxidative stress is responsible for the onset of diabetic complications. This chapter introduces the molecular mechanisms of disease onset due to oxidative stress, including reactive oxygen species, caused by AGEs generated by protein glycation in a hyperglycaemic environment.


Antioxidants ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 344 ◽  
Author(s):  
Rafael Ramis ◽  
Joaquín Ortega-Castro ◽  
Carmen Caballero ◽  
Rodrigo Casasnovas ◽  
Antonia Cerrillo ◽  
...  

Pyridoxamine, one of the natural forms of vitamin B6, is known to be an effective inhibitor of the formation of advanced glycation end products (AGEs), which are closely related to various human diseases. Pyridoxamine forms stable complexes with metal ions that catalyze the oxidative reactions taking place in the advanced stages of the protein glycation cascade. It also reacts with reactive carbonyl compounds generated as byproducts of protein glycation, thereby preventing further protein damage. We applied Density Functional Theory to study the primary antioxidant activity of pyridoxamine towards three oxygen-centered radicals (•OOH, •OOCH3 and •OCH3) to find out whether this activity may also play a crucial role in the context of protein glycation inhibition. Our results show that, at physiological pH, pyridoxamine can trap the •OCH3 radical, in both aqueous and lipidic media, with rate constants in the diffusion limit (>1.0 × 108 M - 1 s - 1 ). The quickest pathways involve the transfer of the hydrogen atoms from the protonated pyridine nitrogen, the protonated amino group or the phenolic group. Its reactivity towards •OOH and •OOCH3 is smaller, but pyridoxamine can still scavenge them with moderate rate constants in aqueous media. Since reactive oxygen species are also involved in the formation of AGEs, these results highlight that the antioxidant capacity of pyridoxamine is also relevant to explain its inhibitory role on the glycation process.


Glycobiology ◽  
2019 ◽  
Vol 30 (1) ◽  
pp. 2-18
Author(s):  
Ejazul Haque ◽  
Mohd Kamil ◽  
Adria Hasan ◽  
Safia Irfan ◽  
Saba Sheikh ◽  
...  

Abstract Protein glycation and protein aggregation are two distinct phenomena being observed in cancer cells as factors promoting cancer cell viability. Protein aggregation is an abnormal interaction between proteins caused as a result of structural changes in them after any mutation or environmental assault. Protein aggregation is usually associated with neurodegenerative diseases like Alzheimer’s and Parkinson’s, but of late, research findings have shown its association with the development of different cancers like lung, breast and ovarian cancer. On the contrary, protein glycation is a cascade of irreversible nonenzymatic reaction of reducing sugar with the amino group of the protein resulting in the modification of protein structure and formation of advanced glycation end products (AGEs). These AGEs are reported to obstruct the normal function of proteins. Lately, it has been reported that protein aggregation occurs as a result of AGEs. This aggregation of protein promotes the transformation of healthy cells to neoplasia leading to tumorigenesis. In this review, we underline the current knowledge of protein aggregation and glycation along with the cross talk between the two, which may eventually lead to the development of cancer.


2018 ◽  
Vol 34 (16) ◽  
pp. 2389-2393
Author(s):  
Bruno Pereira Motta ◽  
Anderson Kiyoshi Kaga ◽  
Juliana Oriel Oliveira ◽  
Maiara Destro Inacio ◽  
Cledson Ferreira da Silva ◽  
...  

Biomedicines ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 88 ◽  
Author(s):  
Samuel Marques ◽  
Teresa Trevisan ◽  
Carlos Maia ◽  
Andrea Breuer ◽  
Robert Owen

Advanced glycation end products (AGEs) represent a set of molecules that contribute directly to the initiation and aggravation of diseases associated with ageing. AGEs are produced by the reaction between reducing sugars (or α-dicarbonyl compounds), proteins, and amino acid residues. Previous in vitro methods using non-enzymatic procedures described in the literature require an incubation period of 1–3 weeks to generate AGEs. In this study, the reaction time for the formation of AGEs (48 and 3 h) was significantly reduced by adaptation of methods previously described in the literature and coupling them to the free radical generation system termed hypoxanthine/xanthine oxidase assay. The incorporation of this assay into the experimental system accelerated the production of AGEs as a result of the formation of reactive oxygen species (ROS), as shown by increased fluorescence. The capacity of different classes of chemical compounds (aminoguanidine, chlorogenic acid, rutin, and methanol extracts of Hancornia speciosa Gomes) to inhibit protein glycation by acting as scavenging agents of α-dicarbonyl species was evaluated. Aminoguanidine and, especially, rutin identified in the leaf extracts of H. speciosa Gomes showed a high capacity to act as scavengers of reactive carbonyl species RCS-trapping, resulting in the inhibition of AGEs formation.


Molecules ◽  
2019 ◽  
Vol 24 (7) ◽  
pp. 1214 ◽  
Author(s):  
Rosa Pérez Gutierrez ◽  
Abraham García Campoy ◽  
Silvia Paredes Carrera ◽  
Alethia Muñiz Ramirez ◽  
José Mota Flores ◽  
...  

Previous studies have shown that accumulation of advanced glycation end products (AGEs) can be the cause of diabetic nephropathy (DN) in diabetic patients. Dihydrochalcone 3′-O-β-d-glucopyranosyl α,4,2′,4′,6′-pentahydroxy–dihydrochalcone (1) is a powerful antiglycation compound previously isolated from Eysenhardtia polystachya. The aim was to investigate whether (1) was able to protect against diabetic nephropathy in streptozotocin (STZ)-induced diabetic mice, which displayed renal dysfunction markers such as body weight, creatinine, uric acid, serum urea, total urinary protein, and urea nitrogen in the blood (BUN). In addition, pathological changes were evaluated including glycated hemoglobin (HbA1c), advanced glycation end products (AGEs) in the kidney, as well as in circulation level and pro-inflammatory markers ICAM-1 levels in diabetic mice. After 5 weeks, these elevated markers of dihydrochalcone treatment (25, 50 and 100 mg/kg) were significantly (p < 0.05) attenuated. In addition, they ameliorate the indices of renal inflammation as indicated by ICAM-1 markers. The kidney and circulatory AGEs levels in diabetic mice were significantly (p < 0.05) attenuated by (1) treatment. Histological analysis of kidney tissues showed an important recovery in its structure compared with the diabetic group. It was found that the compound (1) attenuated the renal damage in diabetic mice by inhibiting AGEs formation.


Author(s):  
Hemalatha S ◽  
Fazeela Mahaboob Begum

 Objective: The current study was intended to investigate and characterize the phytoconstituents of  Sargassum wightii ,evaluate its anti diabetic  and anti inflammatory potential under in silico and in vitro conditions.Methods: The marine algae S.wightii was extracted with ethanol. The ethanolic extract was screened for various phytoconstituents, quantified for total flavonoid and polyphenol content. FTIR and Mass spectrometry was used for characterizing the ethanolic extract. Antidiabetic potential of the phytoconstituents was analysed by molecular docking and enzyme inhibition assays. The anti inflammatory potential was evaluated by albumin denaturation assay.Results: The phytochemical screening revealed the presence of flavonoids, polyphenols, alkaloids, tannins, carbohydrates, proteins, oils and fat present in the ethanol extract. The FTIR analysis showed the presence of α,b unsaturated ketone, alcohol and ether groups in the extract.  MS analysis identified l - (+) - Ascorbic acid 2, 6 dihexadeconoate and Dotriacontyl isopropyl ether in the ethanolic extract. The molecular docking studies revealed that l - (+) - Ascorbic acid 2, 6 dihexadeconoate interacted with both α amylase and α glucosidase with a consensus score of 5.The results of  in vitro analysis showed that the ethanolic extract exhibited strong inhibitory activity on α amylase (IC 50 8mg/ml) and α glucosidase (IC 50 6mg/ml) respectively. The ethanolic extract also inhibited the formation of advanced glycation end products (IC 50 10mg/ml).Further the ethanolic extract inhibited the denaturation of albumin (IC 50 2.5 mg/ml) there by revealing the anti inflammatory potential of S.wightii.Conclusion: Hence it can be concluded that S.wightii possess anti diabetic and anti inflammatory potential which may be due to the presence of l - (+) - Ascorbic acid 2, 6 dihexadeconoate and flavonoids, polyphenols, alkaloids, tannins, carbohydrates, proteins, oils and fat present in the extract.Key words: Sargassum wightii, α amylase, α glucosidase, advanced glycation end products, molecular docking.


2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Nobuyasu Matsuura ◽  
Tadashi Aradate ◽  
Chihiro Kurosaka ◽  
Makoto Ubukata ◽  
Shiho Kittaka ◽  
...  

Plantagoside (5,7,4′,5′-tetrahydroxyflavanone-3′-O-glucoside) and its aglycone (5,7,3′,4′,5′-pentahydroxyflavanone), isolated from a 50% ethanol extract ofPlantago majorseeds (Plantaginaceae), were established to be potent inhibitors of the Maillard reaction. These compounds also inhibited the formation of advanced glycation end products in proteins in physiological conditions and inhibited protein cross-linking glycation. These results indicate thatP. majorseeds have potential therapeutic applications in the prevention of diabetic complications.


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