• Food Science and Biotechnology
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• 제15권4호
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• pp.603-605
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• 2006

Our previous study demonstrated that aqueous ethanolic extract of hardy rubber tree (HRT; Eucommia ulmoides Oliver) leaves potently inhibited glycation, and that two known flavonols and one new flavonol were the active compounds in protein glycation in vitro using the model system of bovine serum albumin and fructose. The aim of this study was to examine the effectiveness of HRT extract and its flavonols against the glycation of hemoglobin (Hb) in primary cultured rat erythrocytes. The extract at $40-400\;{\mu}g/mL$ and the flavonols at $0.2-20\;{\mu}g/mL$ significantly inhibited Hb glycation in a concentration-dependent manner. They were more effective than aminoguanidine, a well-known inhibitor of glycation. Three flavonols seemed to be responsible for the inhibitory activity of the extract, furthermore, the extract of HRT leaves showed advantages over single isolated flavonols in the inhibition of Hb glycation.

• 대한약리학회지
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• 제31권1호
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• pp.135-140
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• 1995

Glycation이란 단당류의 카보릴기와 아미노산의 입실론 아미노기가 공유결합에 의하여 형성되는 반응으로 이는 단백질의 생리적 기능을 변화시키며 아울러 당뇨합병증을 유발한다. 본 연구에서는 warfarin과 dansylsarcosine의 단백질결합에 미치는 glycation의 영향을 평형투석법을 이용하여 연구하였으며 평형투석은 섭씨 37도의 진탕수조에서 3시간 동안 실시하였다. 약물의 농도가 알부민의 농도보다 높을 경우, $50{\pm}16%$가 glycation된 알부민은 $8.5{\pm}5.28%$ glycation 알부민을 함유한 정상알부민에 비해 약물과의 결합도가 낮았으나 warfarin의 농도가 알부민의 3배가 될 경우에만 유의성이 인정되었고(P<0.05) 6%의 차이를 보였다. 본 실험에 나타난 glycation에 의한 유리약물의 미미한 상승효과는 glycated albumin 농도가 낮은 생체내의 여건과, 실제로 사용되는 약물의 적정 치료농도가 낮고 또한 과도한 유리약물은 신장을 통하여 신속히 배설되는 이유로 당뇨환자의 신기능 손상이 없는한 glycation에 의한 유리약물의 상승은 약물중독의 위험요소로 작용되지 않으리라 생각된다.

• Preventive Nutrition and Food Science
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• 제1권1호
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• pp.134-142
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• 1996

Diabetes carries an increased risk of atherosclerotic disease that is not fully explained by known car-diovascular risk factors. There is accumulating evidence that advanced glycation of structural proteins, and oxidation and glycation of circulating lipoproteins, are implicated in the pathogenesis of diabetic ather-osclerosis. Reactions involving glycation and oxidation of proteins and lipids are believed to contribute to atherogenesis. Glycation, the nonenzymatic binding of glucose to protein molecules, can increase the ather-ogenic potential of certain plasma constituents, including low density lipoptotein(LDL). Glycation of LDL is significant increased in diabetic patients compared with normal subjects, even in the presence of good glycemic control. Metabolic abnormalities associated with glycation of LDL include diminished recognition of LDL by the classic LDL receptor; increased covalent binding of LDL in vessel walls ; enhanced uptake of LDL by the macrophages, thus stimulating foam cell formation ; increased platelet aggregation; formation of LDL-immune complexes ; and generation of oxygen free radicals, resulting on oxidative damage to both the lipid and protein components of LDL and to any nearby macromolecules. Oxidized lipoproteins are characterzied by cytotoxicity, potent stimulation of foam cell formation by macrophages, and procoagulant effects. Combined glycation and oxidation, "glycoxidation" occurs when oxidative reactions affect the initial products of glycation, and results in irreversible structural alterations of proteins. Glycoxidation is of greatest significance in long lived proteins such as collagen. In these proteins, glycoxidation products, believed to be atherogenic, accumulate with advancing age : in diabetes, their rate of accumulate is accelerated. Inhibition of glycation, oxidation and glycoxidation may form the basis of future antiaterogenic strategies in both diabetic and nondiabetic individuals.dividuals.

• Asian-Australasian Journal of Animal Sciences
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• 제22권4호
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• pp.591-597
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• 2009

Egg white protein (EWP) was glycated with maltopentaose (MP) through the Maillard reaction and subsequently phosphorylated by $85^{\circ}C$ dry-heating at pH 4.0 for 1 d in the presence of pyrophosphate. The functional properties of glycated, phosphorylated EWP were compared with those of native EWP and with EWP which was phosphorylated by dry-heating in the presence of pyrophosphate under the same conditions. The phosphorus content of EWP was increased to ~0.60% by phosphorylation, and to ~0.74% by glycation with MP and subsequent phosphorylation. The electrophoretic mobility of EWP increased through phosphorylation. The stability of EWP against heat-induced insolubility at pH 7.0 was considerably improved by phosphorylation alone and further by phosphorylation after glycation. The anti-ovalbumin antibody response was reduced significantly by glycation and phosphorylation, and further reduced by phosphorylation after glycation. The anti-ovomucoid antibody response was reduced significantly by glycation, phosphorylation and phosphorylation after glycation. The calcium phosphate-solubilizing ability of EWP was enhanced by both phosphorylation methods.

• 한국식품과학회지
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• 제39권4호
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• pp.458-463
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• 2007

식품소재의 단백질 glycation 저해효과를 조사하기 위하여 곡류, 채소류 및 생약재 등 83종 에탄올 추출물에 대한 단백질 가교결합 저해효과를 $[^{14}C]$-N-formyl-lysine incorporation method를 이용하여 측정하였다. 대부분의 추출물에서 저해효과가 나타났으나 일부 추출물은 단백질의 가교를 촉진하는 것으로 나타났다. 상대적으로 높은 활성을 나타낸 시료 중 20개를 선별하여 형광광도법을 이용한 AGE형성 억제능을 조사한 결과, 1일 발아한 메밀의 추출물 (GB-l)이 가장 높은 저해활성을 가지는 것으로 나타났다. 차후 GB-0l은 콜로로포름, 에틸아세테이트, 부탄올 및 물로 분획되었으며 그 중 에틸아세테이트 분획이 가장 높은 단백질 glycation 저해활성(95.2% inhibitory activity at 100 ug/mL addi- tion level)을 보였다. HPLC를 이용한 폴리페놀 분석결과 발아 및 추출, 분획과정을 거친 메밀의 아세테이트 분획은 rutin 및 quercetin 함량이 상당히 증가한 것으로 나타나서 부분정제물의 rutin 및 quercetin 함량과 저해활성사이에 높은 상관성을 나타내었다.

• Genomics & Informatics
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• 제11권4호
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• pp.224-229
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• 2013

Receptor for advanced glycation endproducts (RAGE) is a multi-ligand receptor that is able to bind several different ligands, including advanced glycation endproducts, high-mobility group protein (B)1 (HMGB1), S-100 calcium-binding protein, amyloid-${\beta}$-protein, Mac-1, and phosphatidylserine. Its interaction is engaged in critical cellular processes, such as inflammation, proliferation, apoptosis, autophagy, and migration, and dysregulation of RAGE and its ligands leads to the development of numerous human diseases. In this review, we summarize the signaling pathways regulated by RAGE and its ligands identified up to date and demonstrate the effects of hyper-activation of RAGE signals on human diseases, focused mainly on renal disorders. Finally, we propose that RAGE and its ligands are the potential targets for the diagnosis, monitoring, and treatment of numerous renal diseases.

• 한국수산과학회지
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• 제42권2호
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• pp.104-108
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• 2009

Glycation and oxidation induce formation of carbonyl (CO) groups in proteins, which can be used to develop an index of cellular aging. Methyl glyoxal (MG) and hypochlorite anions are deleterious products of oxygen free-radical reaction. The effects of eel carnosine on protein modification mediated by MG and hypochlorite were studied. MG and hypochlorite induced formation of carbonyl groups with high molecular weight and cross-linked forms of ovalbumin. The presence of eel carnosine effectively inhibited these modifications in a concentration-dependent manner. Imidazole ring in eel carnosine might have a primary role in inhibition of protein glycation. Our data suggests that the eel carnosine may be useful as a "natural" anti-glycating agents.

• 대한약침학회지
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• 제21권2호
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• pp.82-89
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• 2018

Objective: Diabetes mellitus (DM) is the most common metabolic disorder that defined by chronic hyperglycemia for the deficiency in insulin secretion or resistance. Hyperglycemia could induce non-enzymatic glycation of proteins. It has been suggested that some traditional plants can improve blood glucose and inhibit glycation process. This work evaluates and compares the anti-glycation activities of four Iranian plant extracts in vitro. Methods: The methanolic extract of "Fumaria officinalis, Stachys lavandulifolia, Salvia hydrangea and Rosa Damascene" was prepared in three different concentrations. Phenolic, flavonoids content and antioxidant activity were evaluated. The multistage glycation markers- fructosamines (early stage), protein carbonyls (intermediate stage) and ${\beta}$ aggregation of albumin were investigated in the bovine serum albumin (BSA)/ glucose systemt. Results: All plants showed the high potency of scavenging free radicals and glycation inhibition in the following order: Fumaria officinalis> Rosa Damascene> Stachys lavandulifolia > Salvia hydrangea. There was a significant correlation between antioxidant and anti-glycation activity. Also, the antioxidant and anti-glycation capacity of extracts correlated with total phenolic and flavonoids content. Conclusion: Our findings demonstrated that the studied plants are good sources of anti-glycation and antioxidant compounds and, these properties can primarily attributable to phenolics, particularly flavonoids.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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• pp.197.2-197.2
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• 2003

One of the consequences of hyperglycemia is the excessive nonenzymatic glycation of proteins known as Millard reaction. Under hyperglycemia the irreversibly formed advanced glycation endproducts(AGEs) do not return to normal when hyperglycemia is corrected and continue to accumulate over the lifetime of protein. AGEs are largely involved in the pathogenesis of diabetic complications. To find possible AGEs inhibitor, BSA was added to a mixture of sugars and unprocessed-, processed Coptidis Rhizoma, Berberine, its standard compound or AG(Aminoguanidine HCl: positive control). (omitted)

• The Korean Journal of Physiology and Pharmacology
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• 제18권1호
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• pp.1-14
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• 2014

During long standing hyperglycaemic state in diabetes mellitus, glucose forms covalent adducts with the plasma proteins through a non-enzymatic process known as glycation. Protein glycation and formation of advanced glycation end products (AGEs) play an important role in the pathogenesis of diabetic complications like retinopathy, nephropathy, neuropathy, cardiomyopathy along with some other diseases such as rheumatoid arthritis, osteoporosis and aging. Glycation of proteins interferes with their normal functions by disrupting molecular conformation, altering enzymatic activity, and interfering with receptor functioning. AGEs form intra- and extracellular cross linking not only with proteins, but with some other endogenous key molecules including lipids and nucleic acids to contribute in the development of diabetic complications. Recent studies suggest that AGEs interact with plasma membrane localized receptors for AGEs (RAGE) to alter intracellular signaling, gene expression, release of pro-inflammatory molecules and free radicals. The present review discusses the glycation of plasma proteins such as albumin, fibrinogen, globulins and collagen to form different types of AGEs. Furthermore, the role of AGEs in the pathogenesis of diabetic complications including retinopathy, cataract, neuropathy, nephropathy and cardiomyopathy is also discussed.