• Korean Journal of Pharmacognosy
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• v.43 no.4
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• pp.338-344
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• 2012

Advanced glycation end products (AGEs) have been postulated to play a central role in the development of diabetic complications. A variety of different agents that inhibit AGEs have been under investigation. In this study, 62 herbal medicines from China and Vietnam have been investigated with an in vitro evaluation system using AGEs formation inhibitory activity. Of these, 5 herbal medicines ($IC_{50}$ < $5{\mu}g/ml$) were found to have significant AGEs formation inhibitory activity. Particularly, herbal medicines Albizia odoratissima (twigs and leaves), Rhododendron spinuliferum (twigs and leaves), Dioscorea cirrhosa (stems and leaves), Illicium verum (stems and leaves) and Aglaia perviridis (stems and leaves), showed more potent inhibitory activity (approximately 16-26 fold) than the positive control aminoguanidine ($IC_{50}=76.47{\mu}g/ml$).

• Journal of Physiology & Pathology in Korean Medicine
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• v.26 no.2
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• pp.147-154
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• 2012

Hwanggeum-tang (HGT) was recorded in Dongeuibogam as being able to treat Sogal whose concept had been applied to Diabetes Mellitus (DM). Advanced glycation end products (AGEs) play important roles in the development of diabetic complications such as atherosclerosis by eliciting inflammatory responses. In this study, we examined the suppressive effects of HGT against inflammation elicited by AGEs. AGEs treatment increased the expression of pro-inflammatory cytokine gene TNF-${\alpha}$; chemokines MCP-1, IP-10; pro-inflammatory cyclooxygenase COX-2 on the THP-1 cells. HGT had suppressed the expression of pro-inflammatory genes and protein levels in AGE-treated THP-1 cells. HGT had also decreased intracellular ROS production stimulated by AGEs. These results suggest that HGT has beneficial effects for the improvement diabetic vascular complication through suppressing inflammatory responses elicited by AGEs.

• Korean Journal of Pharmacognosy
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• v.40 no.4
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• pp.382-387
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• 2009

Enhanced formation and accumulation of advanced glycation end products (AGEs) have been implicated as a major pathogenesis process leading to diabetic complications, normal aging, atherosclerosis and Alzheimer's disease. In our ongoing project to discover novel treatments for diabetic complications from natural sources, we have investigated on the inhibitory activity of 67 ethanol extracts from 57 Korean herbal medicines against the formation of AGEs in vitro. Of these, 22 extracts were found to have a significant AGEs inhibitory activity ($IC_{50}$<50 ${\mu}g$/ml) compared with aminoguanidine ($IC_{50}$=75.98 ${\mu}g$/ml). Particularly, 6 extracts from 3 herbal medicines, Castanea crenata (flower, leaf, bark-twig), Acer tatarium subsp. ginnala (fruit) and Sapium japonicum (leaf, twig) showed (approximately 8-17 fold) stronger inhibitory activity than that of aminoguanidine.

• Applied Biological Chemistry
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• v.51 no.4
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• pp.316-320
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• 2008

Ten compounds, (+)-pinoresinol (1), (-)-balanophonin (2), gallicin (3), vanillin (4), 4-hydroxybenzaldehyde (5), coniferaldehyde (6), betulinic acid (7), ursolic acid (8), 5-hydroxymethyl furfural (9), and malic acid (10), were isolated from a EtOAc-soluble fraction of the seeds of Cornus officinalis. The structures of these compounds were elucidated by spectroscopic methods as well as by comparison with reported values. Compounds 1, 2, and 4-7 were isolated from this species for the first time. All the isolates (1-10) were subjected to an in vitro bioassay to evaluate their inhibitory activity against advanced glycation end products (AGEs) formation. Among these, compounds 2 and 3 showed the significant inhibitory activity on AGEs formation with $IC_{50}$ values of 27.81 and 18.04${\mu}M$, respectively.

• Journal of Nutrition and Health
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• v.55 no.3
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• pp.348-358
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• 2022

Purpose: Hyperglycemia accelerates the formation of advanced glycation end products (AGEs), a group of compounds formed via non-enzymatic glycation/glycoxidation. Type 2 diabetes mellitus (T2DM) is related to oxidative stress, resulting in some overgeneration of AGEs. The accumulation of AGEs in T2DM patients leads to increased inflammation, DNA damage, tissue damage, progression of diabetic microvascular disease, and nephropathy. Heme oxygenase-1 (HO-1) is an intracellular enzyme that catalyzes the oxidation of heme. Expression of HO-1 in the endothelium and in muscle monocytes/macrophages was upregulated upon exposure to reactive oxygen species or oxidized low-density lipoprotein. Cells activated by oxidative stress are reported to release HO-1 in the serum. In the current study, we discuss the oxidative status according to the level of AGEs and the association of HO-1 with AGEs or urinary DNA damage marker in type 2 diabetic Korean patients. Methods: This study enrolled 36 diabetic patients. Subjects were classified into two groups by serum AGEs level (Low AGEs group: < 0.85 ng/mL serum AGEs; High AGEs group: ≥ 0.85 ng/mL serum AGEs). Body composition was measured using bioelectrical impedance analysis. Blood and urinary parameters were measured using commercial kits. Results: No significant differences were observed in the general characteristics and body composition between the two groups. Serum HO-1 concentration was significantly higher in the High AGEs group than in the Low AGEs group. After adjustment of age and gender, a correlation was performed to assess the association between serum HO-1 and serum AGEs or urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG). Our results indicate that serum HO-1 is positively correlated with serum AGEs and urinary 8-OHdG. Conclusion: Taken together, our results indicate that in diabetes patients, a high level of HO-1 is associated with a high concentration of AGEs and 8-OHdG, probably reflecting a protective response against oxidative stress.

• Journal of the Korean Society of Food Culture
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• v.37 no.6
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• pp.503-509
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• 2022

Methylglyoxal is a highly reactive precursor which forms advanced glycation end products (AGEs). AGEs and methylglyoxal are known to induce various diseases such as diabetes, vascular disorders, Diabetes Mellitus (DM), and neuronal disorders. Juglans regia L is an important food commonly used worldwide, having nutritious components, including phenolic compounds. Since ancient times, Juglans regia L have been differently applied by various countries for health and in diverse diseases, including arthritis, asthma, skin disorders, cancer, and diabetes mellitus. However, the effect of diabetes-induced renal damage against AGEs remains unclear. This study evaluates the anti-glycation and renal protective effects of ethanol extract of Juglans regia L against methylglyoxal-induced renal tubular epithelial cell death. Exposure to methylglyoxal resulted in reduced cell viability in NRK-52E cells, but co-treatment with Juglans regia L extracts significantly increased the cell viability. In addition, we examined the anti-glycation effect of Juglans regia L extracts. Compared to the positive control aminoguanidine and Alagebrium, treatment with Juglans regia L extracts significantly inhibited the formation of AGEs, collagen cross-linking, and breaking collagen cross-linking. Taken together, our results indicate that Juglans regia L is a potential therapeutic agent for regulating diabetic complications by exerting anti-glycation and renal protective activities.

• Journal of Marine Bioscience and Biotechnology
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• v.13 no.2
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• pp.94-103
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• 2021

Here, we evaluated the anti-glycation effects and renal protective properties of 70% (v/v) ethanolic extract of Colpomenia sinuosa (CSE) against AGEs -induced oxidative stress and apoptosis at different concentrations (1, 5, and 20 ㎍/mL). At 20 ㎍/mL, CSE showed that anti-glycation activities via the inhibition of AGE formation (51.1%), inhibition of AGEs-protein cross-linking (61.7%), and breaking of AGEs-protein cross-links (33.3%), were significantly (###p < 0.001 vs. non-treated group) lower than the nontreated group. Methylglyoxal (MGO) significantly (***p < 0.001) reduced cell viability (24.4%) and increased reactive oxygen species (ROS) level (642.3%), MGO accumulation (119.4 ㎍/mL), and apoptosis (55.0%) in mesangial cells compared to the nontreated group. Pretreatment with CSE significantly (###p < 0.001) increased cell viability (57.8%) and decreased intracellular ROS (96.5%), MGO accumulation (80.0 ㎍/mL), and apoptosis (22.6%) at 20 ㎍/mL. Additionally, we confirmed intracellular AGEs reduction by CSE pretreatment. Consequently, our results suggest that CSE is a good source of natural therapeutics for managing diabetic complications by the antiglycation effect and renal protective activity against MGO-induced oxidative stress.

• Analytical Science and Technology
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• v.35 no.1
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• pp.8-14
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• 2022

Many studies have shown that advanced glycation end-products (AGEs) and glycation adducts are significantly linked to aging and disease. Particularly, the level of glycation in human milk is important because the AGE intake is closely related to AGE levels in infants. In this study, we used human milk samples obtained from four primiparae and four multiparae. We isolated proteins using acetone and trichloroacetic acid (TCA) precipitation. A total of 67 glycated proteins and 122 glycated peptides was quantified; among them, 19 glycated peptides were differentially expressed. We confirmed that the degree of glycation differed according to fertility. The study provides a foundation for using proteomics to evaluate the mother's milk quality and link between maternal health and human milk quality.

• Fisheries and Aquatic Sciences
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• v.25 no.10
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• pp.517-524
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• 2022

Over production of methylglyoxal (MGO) a highly reactive dicarbonyl compound, has been associated in progressive diabetes with vascular complication. Therefore, we investigated whether hot water extract of Loliolus beka meat (LBM-HWE) presents a preserve effect against MGO-induced cellular damage in human umbilical vein endothelial cells (HUVECs). The LBM-HWE extract showed to inhibit MGO-induced cytotoxicity. Additionally, the LBM-HWE reduced mRNA expression of pro-inflammatory cytokines, and reduced MGO-induced advanced glycation end product (AGEs) formation. Furthermore, LBM-HWE induced glyoxalase-1 mRNA expression and reduced MGO-induced carbonyl protein formation in HUVECs. The results implicate that LBM-HWE has protective ability against MGO-induced HUVECs toxicity by preventing AGEs formation. In conclusion, LBM-HWE could be used as a potential treatment material for the prevention of vascular complications of diabetes.

• International Journal of Oral Biology
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• v.49 no.2
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• pp.27-33
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• 2024

Diabetes, a chronic hyperglycemic condition, is caused by insufficient insulin secretion or functional impairment. Long-term inadequate regulation of blood glucose levels or hyperglycemia can lead to various complications, such as retinopathy, nephropathy, and cardiovascular disease. Recent studies have explored the molecular mechanisms linking diabetes to bone loss and an increased susceptibility to fractures. This study reviews the characteristics and molecular mechanisms of diabetes-induced bone disease. Depending on the type of diabetes, changes in bone tissue vary. The molecular mechanisms responsible for bone loss in diabetes include the accumulation of advanced glycation end products (AGEs), upregulation of inflammatory cytokines, induction of oxidative stress, and deficiencies in insulin/IGF-1. In diabetes, alveolar bone loss results from complex interactions involving oral bacterial infections, host responses, and hyperglycemic stress in periodontal tissues. Therapeutic strategies for diabetes-induced bone loss may include blocking the AGEs signaling pathway, decreasing inflammatory cytokine activity, inhibiting reactive oxygen species generation and activity, and controlling glucose levels; however, further research is warranted.