Increased expression of advanced glycation endproducts in the gingival crevicular fluid compromises periodontal status in cigarette-smokers and waterpipe users.

BACKGROUND: The aim was to assess the association between levels of advanced glycation endproducts (AGEs) in the gingival crevicular fluid (GCF) and periodontal parameters among cigarette-smokers and waterpipe-users. METHODS: Self-reported cigarette-smokers; waterpipe-users and never-smokers were included. Demographic data was recorded using a questionnaire. Periodontal parameters (plaque index [PI], gingival index [GI], clinical attachment loss [AL], probing depth [PD], and marginal bone loss [MBL]) were assessed in all groups. The GCF samples were collected using standard techniques and assessed for AGEs levels using enzyme-linked immunosorbent assay. Sample-size estimation was done and group-comparisons were done. Correlation between levels of GCF AGEs levels and periodontal parameters was assessed using a logistic regression model. Level of significance was set at P < 0.01. RESULTS: Eighty-two individuals (28 cigarette-smokers, 28 waterpipe-users and 26 never-smokers) were included. There was no difference in mean ages of all patients. Cigarette-smokers had a smoking history of 5.1 ± 0.2 pack years and waterpipe-users were using waterpipe for 4.4 ± 0.6 years. There was no statistically significant difference in PI, GI, clinical AL, PD and MBL in all groups. Levels of AGEs were significantly higher among cigarette-smokers (P < 0.001) and waterpipe-users (P < 0.001) than never-smokers. There was no significant correlation between levels of GCF AGEs levels and periodontal parameters in all groups. CONCLUSION: Clinical periodontal status of individuals with a short history of cigarette-smoking and waterpipe-usage may appear similar to never-smokers. On a molecular level, cigarette-smoking and waterpipe-users express raised levels of AGEs than never-smokers that sirens about the ongoing yet latent periodontal inflammatory process.

Matrine inhibits advanced glycation end products-induced macrophage M1 polarization by reducing DNMT3a/b-mediated DNA methylation of GPX1 promoter.

Advanced glycation end products (AGEs) are characterized diabetic metabolites inducing macrophage M1 polarization which is crucial in diabetes-exacerbated atherosclerosis. Matrine was proved anti-atherosclerotic. The current study was aimed to investigate the inhibitory effects of matrine on AGEs- induced macrophage M1 polarization and underlying molecular mechanisms. Primary mouse macrophages were exposed to AGEs. Receptor for AGEs (RAGE) and toll-like receptor 4 (TLR4) were over-expressed by vectors. Matrine was used to treat these cells. Inducible nitric oxide synthase (iNOS) expression and pro-inflammatory cytokine production were used to evaluate macrophage M1 polarization. Oxidative stress was assessed by intracellular reactive oxygen species (ROS) generation, total antioxidant capacity (TAC) and malondialdehyde (MDA) contents. Relative mRNA expression level was determined by real-time PCR. Western blotting was used to evaluate protein and protein phosphorylation levels. Bisulfite sequencing PCR (BSP) was used to evaluate DNA methylation. Matrine reduced AGEs exposure-elevated expressions of DNA methyltransferase (DNA MTase, DNMT)3a and DNMT3b in macrophages which were not affected by RAGE or TLR4 over expressions. DNA methylation rate of GPX1 promoter was reduced from 97.22% to 66.67% in AGEs- exposed macrophages treated by matrine. GPX1 expression was up-regulated by matrine, which further suppressed AGEs/RAGE-mediated oxidative stress. Thus, the activation of down-stream TLR4/STAT1 signaling pathway was inhibited by matrine treatment which eventually suppressed AGEs- induced macrophage M1 polarization. However, these effects of matrine were impaired by RAGE and TLR4 overexpression. Results from this study suggested that matrine inhibited AGEs- induced macrophage M1 polarization by suppressing RAGE-induced oxidative stress-mediated TLR4/STAT1 signaling pathway. Matrine exerted anti-oxidant effects via increasing GPX1 expression by inhibiting DNMT3a/b-induced GPX1 promoter DNA methylation.

Study on the Mechanism of Prunella Vulgaris L on Diabetes Mellitus Complicated with Hypertension Based on Network Pharmacology and Molecular Docking Analyses.

The role of traditional Chinese medicine Prunella vulagaris L in the treatment of tumors and inflammation has been widely confirmed. We found that some signaling pathways of Prunella vulgaris L action can also regulate diabetes and hypertension, so we decided to study the active ingredients, potential targets and signaling pathway of Prunrlla vulgaris L, and explore the "multi-target, multi-pathway" molecular mechanism of Prunella vulgaris L on diabetes mellitus complicated with hypertension(DH). Methods. Based on TCMSP(Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform) and CNKI(China National Knowledge Infrastructure), the components and action targets related to Prunella vulgaris L were screened. The OMIM(Online Mendelian Inheritance in Man) and GeneCards (The human gene database) were used to search for targets related to DH. The "gene - drug - disease" relationship map was drawn by Cytoscape_v3.7.2 plug-in. The target was amplified by the STRING platform, and the "protein - protein" interaction relationship (PPI) network of the interacting target was obtained by the STRING online analysis platform and the Cytoscape_v3.7.2 plug-in. Finally, GO enrichment analysis and KEGG pathway enrichment analysis were conducted on David and Metascape platform to study the co-acting targets. Results. 11 active components, 41 key targets and 16 significant signaling pathways were identified from Prunella vulgaris L. The main active components of Prunella vulgaris L against DH were quercetin and kaumferol, etc, and potential action targets were IL-6 and INS, etc and signaling pathways were AGE-RAGE signaling pathway, TNF signaling pathway, MAPK signaling pathway, PI3K-AKT signaling pathway, etc. It involves in biological processes such as cell proliferation, apoptosis and inflammatory response. Conclusions. The main molecular mechanism of Prunella vulgaris L against DH is that sterols and flavonoids play an active role by affecting TNF signaling pathway, AGE-RAGE signaling pathway, MAPK pathway, PI3K-Akt pathway related targets such as IL-6 and INS.

Inhibition of advanced glycation endproducts formation by lotus seedpod oligomeric procyanidins through RAGE-MAPK signaling and NF-κB activation in high-AGEs-diet mice.

This study investigated the modulatory effects of lotus seedpod oligomeric procyanidins (LSOPC) on the advanced glycation endproducts (AGEs)-induced liver injury via advanced glycation end-product receptors (RAGE)-mitogen-activated protein kinases (MAPK)-nuclear factor-kappa B (NF-κB) signaling pathways in a mice model. To examine the antioxidation properties of LSOPC, a model of high-AGEs-diet were established using Sprague Dawley (SD) male mice fed with a normal AIN-93G diet, a high AGEs diet (H), or H plus 0.5 or 0.2% (w/w) LSOPC for 12 weeks. Our results showed that LSOPC inhibited the AGEs formation and alleviated AGEs-induced liver injury by suppressing the nuclear translocation of NF-κB and activation of the MAPK signaling pathway. Additionally, LSOPC inhibited the genes expression of tumor necrosis factor-α (TNF-α) and interleukin 6 (IL-6). Taken together, LSOPC treatment potentially inhibited the AGEs formation and modulated liver injury with long-term dietary AGEs by suppressing RAGE-MAPK-NF-κB pathways.

Comprehensive evaluation of two Astragalus species (A. campylosema and A. hirsutus) based on biological, toxicological properties and chemical profiling.

Astragalus L. (Fabaceae) is an important genus with numerous species having various traditional medicinal uses making them of interest for scientific investigations to ascertain their therapeutic benefits. In the present study, the quantitative polyphenolic profiles of methanolic extracts from different parts (leaves, flowers, and roots) of two endemic Astragalus species growing in Turkey, i.e. A. campylosema Boiss. and A. hirsutus Vahl were determined, along with their antioxidant and enzyme inhibitory properties. A. campylosema and A. hirsutus extracts showed varying total phenolic (25.80-40.60 and18.59-29.46 mg GAE/g, respectively) and total flavonoid (11.21-105.91 and 16.06-131.91 mg RE/g, respectively) contents. HPLC-MS/MS revealed rutin to be the predominant phenolic compound in all the extracts of A. campylosema and leaf extract of A. hirsutus (133.53-752.42 µg g-1), while hyperoside was the major one in the flower and root extracts of A. hirsutus (2014.07 and 123.13 µg g-1, respectively). In DPPH and ABTS assays, radical scavenging capacity was demonstrated by all extracts of A. campylosema (47.13-48.10 and 87.03-115.36 mg TE/g, respectively) and A. hirsutus (17.82-38.67 and 47.84-57.29 mg TE/g, respectively). Reducing activity was also displayed by the extracts in CUPRAC and FRAP assays (A. campylosema: 83.06-135.20 and 59.15-90.19 mg TE/g, respectively; A. hirsutus: 53.02-83.42 and 31.25-43.25 mg TE/g, respectively). All extracts were also found to act as metal chelators (12.32-21.45 mg EDTAE/g) and exhibited total antioxidant capacity ranging from 1.16 to 1.60 mmol TE/g, in phosphomolybdenum assay. Acetyl- and butyryl-cholinesterase inhibitory effects were observed by all the extracts of the two species (1.56-4.99 mg GALAE/g). Anti-hyperpigmentation potential by inhibiting tyrosinase (54.55-67.35 mg KAE/g) was reported as well. Carbohydrate hydrolyzing enzymes, amylase and glucosidase were also inhibited (0.22-1.03 mmol ACAE/g). Overall, A. campylosema extracts showed relatively better antioxidant and enzyme inhibitory potentials compared to A. hirsutus extracts. Strikingly, A. hirsutus extracts was found to have higher AGE inhibition activity than A. campylosema. Although the cytotoxic effect of three different organs obtained from A. campylosema and A. hirsutus increased depending on the dose (from 10 to 200 µg/mL), it was found that both plant extracts did not show a genotoxic effect at the highest concentration of 200 µg/mL. Indeed, data amassed from this current scientific work showed the two selected Astragalus species to be rich in bioactive polyphenols that could be responsible for the various pharmacological activities and hence demands to be further explored for their possible applications as natural health promoting agents.

Network Pharmacology and Molecular Docking Study on the Potential Mechanism of Yi-Qi-Huo-Xue-Tong-Luo Formula in Treating Diabetic Peripheral Neuropathy.

OBJECTIVE: To investigate the potential mechanism of action of Yi-Qi-Huo-Xue-Tong-Luo formula (YQHXTLF) in the treatment of diabetic peripheral neuropathy (DPN). METHODS: Network pharmacology and molecular docking techniques were used in this study. Firstly, the active ingredients and the corresponding targets of YQHXTLF were retrieved using the Traditional Chinese Medicine Systems Pharmacology (TCMSP) platform; subsequently, the targets related to DPN were retrieved using GeneCards, Online Mendelian Inheritance in Man (OMIM), Pharmgkb, Therapeutic Target Database (TTD) and Drugbank databases; the common targets of YQHXTLF and DPN were obtained by Venn diagram; afterwards, the "YQHXTLF Pharmacodynamic Component-DPN Target" regulatory network was visualized using Cytoscape 3.6.1 software, and Gene Ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were performed on the potential targets using R 3.6.3 software. Finally, molecular docking of the main chemical components in the PPI network with the core targets was verified by Autodock Vina software. RESULTS: A total of 86 active ingredients and 229 targets in YQHXTLF were screened, and 81 active ingredients and 110 targets were identified to be closely related to diabetic peripheral neuropathy disease. PPI network mapping identified TP53, MAPK1, JUN, and STAT3 as possible core targets. KEGG pathway analysis showed that these targets are mostly involved in AGE-RAGE signaling pathway in diabetic complications, TNF signaling pathway, and MAPK signaling pathway. The molecular docking results showed that the main chemical components of YQHXTLF have a stable binding activity to the core pivotal targets. CONCLUSION: YQHXTLF may act on TP53, MAPK1, JUN, and STAT3 to regulate inflammatory response, apoptosis, or proliferation as a molecular mechanism for the treatment of diabetic peripheral neuropathy, reflecting its multitarget and multipathway action, and providing new ideas to further uncover its pharmacological basis and mechanism of action.

Water Extract of Mungbean (Vigna radiata L.) Inhibits Protein Tyrosine Phosphatase-1B in Insulin-Resistant HepG2 Cells.

The present study aimed to investigate the effects of mungbean water extract (MWE) on insulin downstream signaling in insulin-resistant HepG2 cells. Whole seed mungbean was extracted using boiling water, mimicking a traditional cooking method. Vitexin and isovitexin were identified in MWE. The results showed that MWE inhibited protein tyrosine phosphatase (PTP)-1B (IC50 = 10 µg/mL), a negative regulator of insulin signaling. MWE enhanced cellular glucose uptake and altered expression of genes involved in glucose metabolism, including forkhead box O1 (FOXO1), phosphoenolpyruvate carboxykinase (PEPCK), and glycogen synthase kinase (GSK)-3ß in the insulin-resistant HepG2 cells. In addition, MWE inhibited both α-amylase (IC50 = 36.65 mg/mL) and α-glucosidase (IC50 = 3.07 mg/mL). MWE also inhibited the formation of advanced glycation end products (AGEs) (IC50 = 2.28 mg/mL). This is the first study to show that mungbean water extract increased cellular glucose uptake and improved insulin sensitivity of insulin-resistant HepG2 cells through PTP-1B inhibition and modulating the expression of genes related to glucose metabolism. This suggests that mungbean water extract has the potential to be a functional ingredient for diabetes.

The impact of high-pressure processing on the polyphenol profile and anti-glycaemic, anti-hypertensive and anti-cholinergic activities of extracts obtained from kiwiberry (Actinidia arguta) fruits.

This study analysed the impact of high pressure processing (HHP) on the inhibitory effects (IC50) of kiwiberries (cv. 'Weiki'), on the formation of advanced glycation end-products (AGEs) and the activity of angiotenisn-converting enzyme (ACE) and the enzyme acetylcholinesterase (AChE). The polyphenol profile (HPLC-MS/MS) and antioxidant capacity (PCLACW, ABTS, FRAP) were also studied. HHP-treated 'Weiki' (450 MPa/5 min and 650 MPa/5 min) was the most potent inhibitor of AGEs in the BSA-GLU model (6.52 mg/mL on average) relative to other materials (12.09-7.21 mg/mL). Among all samples assayed in the BSA-MGO model (61.97-14.48 mg/mL), HHP-treated 'Weiki' (450 MPa/5 min) showed the highest anti-AGE activity (12.37 mg/mL). Pressurization (450 MPa/5 min) significantly enhanced the anti-ACE (14.09 mg/mL) and anti-AChE (16.95 mg/mL) potentials of the tested extract relative to the other materials (23.75-14.50 mg/mL and 37.88-19.69 mg/mL, respectively). Pressurization increased polyphenol content and antioxidant capacity of the samples analysed.

Liraglutide improved the cognitive function of diabetic mice via the receptor of advanced glycation end products down-regulation.

Background and aims Advanced glycation end products (AGEs) and receptor of advanced glycation end products (RAGE), are associated with cognition decline. We aim to investigate the effect of liraglutide on cognitive function in diabetic mice. Results Diabetic mice showed decreased cognitive function. Moreover, lower glucagon like peptide-1 (GLP-1) levels in plasma were detected in db/db mice. Additionally, up-regulated RAGE and down-regulated glucagon like peptide-1 (GLP-1R) levels were observed in db/db mice. However, decreased GLP-1R and increased RAGE were reversed by liraglutide. We also found decreased cellular activity in cells with AGEs. Moreover, AGEs up-regulated RAGE in PC12 and HT22 cells. However, liraglutide improved the cell activity damaged by AGEs. Although we did not discover the direct-interaction between RAGE and GLP-1R, elevated RAGE levels induced by AGEs were restored by liraglutide. Conclusion We demonstrated that the cognitive function of diabetic mice was improved by liraglutide via the down-regulation of RAGE. Methods db/db mice and db/m mice were used in this study. Liraglutide was used to remedy diabetic mice. Neurons and RAGE in hippocampus were shown by immunofluorescence. And then, PC12 cells or HT22 cells with AGEs were treated with liraglutide. GLP-1R and RAGE were measured by western blotting.

Morroniside attenuates high glucose-induced BMSC dysfunction by regulating the Glo1/AGE/RAGE axis.

OBJECTIVES: High glucose (HG)-mediated bone marrow mesenchymal stem cell (BMSC) dysfunction plays a key role in impaired bone formation induced by type 1 diabetes mellitus (T1DM). Morroniside is an iridoid glycoside derived from the Chinese herb Cornus officinalis, and it has abundant biological activities associated with cell metabolism and tissue regeneration. However, the effects and underlying mechanisms of morroniside on HG-induced BMSC dysfunction remain poorly understood. MATERIALS AND METHODS: Alkaline phosphatase (ALP) staining, ALP activity and Alizarin Red staining were performed to assess the osteogenesis of BMSCs. Quantitative real-time PCR and Western blot (WB) were used to investigate the osteo-specific markers, receptor for advanced glycation end product (RAGE) signalling and glyoxalase-1 (Glo1). Additionally, a T1DM rat model was used to assess the protective effect of morroniside in vivo. RESULTS: Morroniside treatment reverses the HG-impaired osteogenic differentiation of BMSCs in vitro. Morroniside suppressed advanced glycation end product (AGEs) formation and RAGE expression by triggering Glo1. Moreover, the enhanced osteogenesis due to morroniside treatment was partially blocked by the Glo1 inhibitor, BBGCP2. Furthermore, in vivo, morroniside attenuated bone loss and improved bone microarchitecture accompanied by Glo1 upregulation and RAGE downregulation. CONCLUSIONS: These findings suggest that morroniside attenuates HG-mediated BMSC dysfunction partly through the inhibition of AGE-RAGE signalling and activation of Glo1 and may be a potential treatment for diabetic osteoporosis.

Study on Effects and Mechanism of Lead and High-Fat Diet on Cognitive Function and Central Nervous System in Mice.

OBJECTIVE: We sought to investigate the effects and mechanism of lead and a high-fat diet on cognitive function and the central nervous system in mice. METHODS: Eighty-four healthy male mice were randomly divided into a control group (n = 21) (fed with common diet and free drinking), a lead exposure group (n = 21) (fed with common diet and 300 mg/L lead acetate solution), a high-fat group (n = 21) (fed with high-fat diet and free drinking), and a lead + high-fat group (n = 21) (fed with high-fat diet and 300 mg/L lead acetate solution). In 10 weeks after lead exposure, the mice of all groups were tested for the cognition, learning and memory abilities, body weight, serum triglyceride (TG), low-density lipoprotein, and high-density lipoprotein, as well as for the contents of lead, interleukin 6 (IL-6), interleukin 17 (IL-17), interferon γ, advanced glycation end products (AGEs), glutathione S-transferase (GSH-ST), and hydrogen peroxide in the brain tissues. RESULTS: Compared with the control group and the lead-exposed group, the body weights of mice in the high-fat group and the lead + high-fat group increased significantly from the sixth week of the experiment, of which the difference was statistically significant (P < 0.05). Compared with the control group and the high-fat group, the lead content in brain tissue of the lead exposure group and the lead + high-fat group increased significantly, of which the difference was statistically significant (P < 0.05). Compared with the control group, the escape latent period, triglyceride, low-density lipoprotein, IL-6, IL-17, interferon γ, and AGEs of the remaining 3 groups increased significantly, but the recognition index, passing platform times, high-density lipoprotein, and GSH-ST significantly decreased (P < 0.05); the second and third escape latent periods, IL-6, IL-17, and AGEs of lead + high-fat group, were obviously higher than the remaining 3 groups, but the passing platform times were obviously lower than the remaining 3 groups, of which the difference was statistically significant. The content of hydrogen peroxide in brain tissues had no difference among groups (P > 0.05). CONCLUSIONS: The lead and high-fat diet resulted in lipid metabolism disorders and impaired the cognitive function and central nervous system by promoting the secretion of inflammatory factors in glial cells, inducing the inflammatory reaction of brain tissue, inhibiting GSH-ST expression, and increasing AGEs content.

l-Theanine attenuates liver aging by inhibiting advanced glycation end products in d-galactose-induced rats and reversing an imbalance of oxidative stress and inflammation.

Redox and inflammation imbalances are associated with increased levels of advanced glycation end products (AGEs), leading to the degeneration of body function. l-Theanine, derived from tea, reportedly inhibits AGE formation in vitro. We investigated the effects on AGE content, oxidative stress, and inflammatory factors in d-galactose-induced aging rats for prevention and treatment of age-related liver dysfunction. l-Theanine increased activities of antioxidant enzymes such as superoxide dismutase, catalase, and glutathione peroxidase, thus enhancing total antioxidant capacity, and decreasing malondialdehyde and nitric oxide synthase levels in serum and liver. Levels of the pro-inflammatory factors, interleukin (IL)-1ß, tumour necrosis factor-alpha, and IL-6 were decreased in serum and liver, whereas those of anti-inflammatory factors, IL-4 and IL-10, were increased in the serum. Further, l-theanine inhibited AGE production and decreased the levels of the liver function markers, alanine aminotransaminase and aspartate aminotransferase. It also significantly increased the mRNA expression levels of FoxO1 and downregulated NF-κB(p65) but suppressed the phosphorylation of both FOXO1 and NF-κB (p65). Moreover, l-theanine effectively attenuated d-galactose-induced oedema and vacuole formation, thus protecting the liver. Overall, l-theanine reversed the d-galactose-induced imbalance in oxidative stress and inflammatory responses, reduced AGEs content in aging rats, maintained homeostasis in the body, and ameliorated liver aging.

Zafirlukast, a Cysteinyl Leukotriene Receptor 1 Antagonist, Reduces the Effect of Advanced Glycation End-Products in Rat Renal Mesangial Cells In Vitro.

BACKGROUND Zafirlukast is an antagonist of cysteinyl leukotriene receptor 1 (CysLTR1). Advanced glycation end-products (AGEs) are formed by the glycation of lipids and proteins in hyperglycemia, including diabetes mellitus. Zafirlukast has not previously been studied in diabetic nephropathy. This study aimed to investigate the effects of zafirlukast on rat renal mesangial cells cultured with AGEs in vitro. MATERIAL AND METHODS Mesangial cells were cultured in AGEs (0, 20, 50, 100 µg/ml), and with AGEs (100 µg/ml) and zafirlukast (2.5 µm, 5 µm, and 100 µm). An enzyme-linked immunoassay (ELISA) was used to measure the levels of tumor necrosis factor-alpha (TNF-alpha), interleukin-1ß (IL-1ß), IL-6, and monocyte chemoattractant protein-1 (MCP-1). Reactive oxygen species (ROS) were assessed by intracellular fluorescence measurement of 2'-7'-dichlorodihydrofluorescein diacetate (DCFH-DA), and detection kits were used to measure malondialdehyde (MDA), lactate dehydrogenase (LDH), glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD). Cell apoptosis was assessed by flow cytometry, and Western blot was used to measure protein levels. RESULTS In mesangial cells cultured with AGEs, markers of inflammation, oxidative stress, and apoptosis and levels of CysLTR1 increased, and these effects were reduced by zafirlukast in a dose-dependent manner. The effects of zafirlukast as a CysLTR1 antagonist protected mesangial cells from the effects of AGE in vitro. CONCLUSIONS Zafirlukast, a CysLTR1 antagonist, reduced the levels of inflammatory cytokines, markers of oxidative stress, and cell apoptosis induced by AGE in mesangial cells in a dose-dependent way. Future in vivo studies are needed to investigate the potential role for zafirlukast in models of diabetic nephropathy.

Protective effect of vanillin on diabetic nephropathy by decreasing advanced glycation end products in rats.

AIMS: Diabetic nephropathy (DN) is a common chronic microvascular complication of both types of diabetes mellitus, which leads to renal dysfunction and subsequent need of dialysis and organ transplantation. Advanced glycation end products (AGEs) are metabolic consequence of hyperglycemia and are main contributory factor in the DN pathogenesis through mediating establishment of oxidative status and chronic inflammatory milieu. This study aimed to explore the impact of vanillin on preventing the progression of DN. MAIN METHODS: Experimental DN model was established in rats utilizing streptozotocin. Serum concentration of AGEs and Interleukin-6 (IL-6) and transforming growth factor ß1 (TGFß1) levels in kidney homogenate were assessed using ELISA technique. Also, we evaluated the expression of nuclear factor kappa B (NF-κB) using immunohistochemistry. KEY FINDINGS: Treatment with vanillin for 8 weeks significantly ameliorated DN. Vanillin significantly decreased hyperglycemia and improved kidney function reflected by decreased serum levels of blood urea nitrogen, creatinine, and decreased proteinuria. Also, vanillin significantly decreased malondialdehyde content and elevated superoxide dismutase activity in renal tissues. Moreover, vanillin decreased renal expression of NF-κB and renal concentrations of IL-6, TGFß1 and collagen. In addition, vanillin significantly decreased serum AGEs concentration. Also, vanillin attenuated histological abnormalities in kidney architecture. SIGNIFICANCE: Vanillin, which is a cheap and abundant natural product, exhibited anti-AGEs, antioxidant, anti-inflammatory and anti-fibrotic activities. These activities might be helpful and potent mechanisms in preventing the progression of DN.

Demethoxycurcumin: A naturally occurring curcumin analogue for treating non-cancerous diseases.

Turmeric extracts contain three primary compounds, which are commonly referred to as curcuminoids. They are curcumin, demethoxycurcumin (DMC), and bisdemethoxycurcumin. While curcumin has been the most extensively studied of the curcuminoids, it suffers from low overall oral bioavailability due to extremely low absorption as a result of low water solubility and instability at acidic pH, as well as rapid metabolism and clearance from the body. However, DMC, which lacks the methoxy group on the benzene ring of the parent structure, has much greater chemical stability at physiological pH and has been recently reported to exhibit antitumor properties. However, the treatment of noncancerous diseases with DMC has not been comprehensively reviewed. Therefore, here we evaluate published scientific literature on the therapeutic properties of DMC. The beneficial pharmacological actions of DMC include anti-inflammatory, neuroprotective, antihypertensive, antimalarial, antimicrobial, antifungal, and vasodilatory properties. In addition, DMC's ability to ameliorate the effects of free radicals and an environment characterized by oxidative stress caused by the accumulation of advanced glycation end-products associated with diabetic nephropathy, as well as DMC's capacity to inhibit the migration and proliferation of vascular smooth muscle cells following balloon angioplasty are also addressed. This review collates the available literature regarding the therapeutic possibilities of DMC in noncancerous conditions.

Icariin Inhibits AGE-Induced Injury in PC12 Cells by Directly Targeting Apoptosis Regulator Bax.

Diabetic encephalopathy (DE) is a serious complication caused by long-term cognitive impairment in diabetic patients. At present, there is no effective treatment for DE. Icariin (ICA) is a bioactive ingredient isolated from Epimedium. Previous research indicated that ICA was neuroprotective against Aß-induced PC12 cell insult; however, the effect of ICA on an advanced glycosylation end product- (AGE-) induced neural injury model has not been studied. In this study, we investigated the neuroprotective effects of ICA on AGE-induced injury in PC12 cells. Our findings revealed that ICA could effectively protect PC12 cells from AGE-induced cell apoptosis by suppressing oxidative stress. Moreover, we observed that ICA could significantly protect against mitochondrial depolarization following AGE stimulation and inactivate the mitochondria-dependent caspase-9/3 apoptosis pathway. Most notably, we identified the direct target protein of ICA as apoptosis regulator Bax by a pulldown assay. We found that ICA could specifically target Bax protein and inhibit Bax dimer formation and migration to mitochondria. Furthermore, a siRNA knockdown experiment revealed that ICA could inhibit PC12 cell apoptosis and oxidative stress through targeting Bax. Taken together, our findings demonstrated that ICA could attenuate AGE-induced oxidative stress and mitochondrial apoptosis by specifically targeting Bax and further regulating the biological function of Bax on mitochondria.

Ascorbic acid leads to glycation and interferes with neurite outgrowth.

Ascorbic acid better known as vitamin C, is a reducing carbohydrate needed for a variety of functions in the human body. The most important characteristic of ascorbic acid is the ability to donate two electrons, predestining it as a major player in balancing the physiological redox state and as a necessary cofactor in multiple enzymatic hydroxylation processes. Ascorbic acid can be reversibly oxidized in two steps, leading to semidehydroascorbic acid and dehydroascorbic acid, respectively. Further degradation is irreversible and generates highly reactive carbonyl-intermediates. These intermediates are able to induce glycation of proteins, a non-enzymatic and unspecific reaction of carbonyls with amino groups involved to several age-related diseases. In this study, we investigated the effect of ascorbic acid- and dehydroascorbic acid-induced glycation on PC12 cells, which represent a model for neuronal plasticity. We found that both applications of ascorbic acid or dehydroascorbic acid leads to glycation of cellular proteins, but that ascorbic acid interferes more with viability and neurite outgrowth compared with dehydroascorbic acid.

The Antioxidant Effects of Hydroxytyrosol and Vitamin E on Pediatric Nonalcoholic Fatty Liver Disease, in a Clinical Trial: A New Treatment?

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in children. Several studies suggest that the improvement of oxidative stress is suggested as a possible therapeutic strategy for pediatric nonalcoholic steatohepatitis. We performed a randomized, double-blind placebo-controlled trial to test the potential efficacy, assessed by improvement of oxidative stress parameters and liver ultrasound, and tolerability of a mixture of vitamin E and hydroxytyrosol (HXT) in adolescents with biopsy-proven NAFLD. Four hundred forty consecutive patients were screened, 80 of these with biopsy-proven NAFLD were enrolled. Forty patients received an oral dose of HXT and vitamin E and 40 children received the capsules of placebo for 4 months. Seventy patients completed the study. Patients in the treatment arm showed a decrease of insulin resistance (IR), triglyceride levels, oxidative stress parameters, and steatosis grade. Noteworthy, the steatosis improvement correlates with the levels of advanced glycation end products and carbonylated proteins. The HXT and vitamin E treatment improved the main oxidative stress parameters, IR, and steatosis in children with NAFLD. The use of two natural molecules that may have antioxidant effects seems a promising strategy that could be easily diet integrated to improve NAFLD-related liver damage in children.

Diphlorethohydroxycarmalol Attenuates Methylglyoxal-Induced Oxidative Stress and Advanced Glycation End Product Formation in Human Kidney Cells.

Diabetic nephropathy is the leading cause of end-stage renal disease in patients with diabetes mellitus. Oxidative stress has been shown to play an important role in pathogeneses of renal damage in diabetic patients. Here, we investigated the protective effect of diphlorethohydroxycarmalol (DPHC), which is a polyphenol isolated from an edible seaweed, Ishige okamurae, on methylglyoxal-induced oxidative stress in HEK cells, a human embryonic kidney cell line. DPHC treatment inhibited methylglyoxal- (MGO-) induced cytotoxicity and ROS production. DPHC activated the Nrf2 transcription factor and increased the mRNA expression of antioxidant and detoxification enzymes, consequently reducing MGO-induced advanced glycation end product formation. In addition, DPHC increased glyoxalase-1 mRNA expression and attenuated MGO-induced advanced glycation end product formation in HEK cells. These results suggest that DPHC possesses a protective activity against MGO-induced cytotoxicity in human kidney cells by preventing oxidative stress and advanced glycation end product formation. Therefore, it could be used as a potential therapeutic agent for the prevention of diabetic nephropathy.

Polyphenols from Euphorbia pekinensis Inhibit AGEs Formation In Vitro and Vessel Dilation in Larval Zebrafish In Vivo.

To identify active compounds in the roots of Euphorbia pekinensis for treatment of diabetic complications, an active column fraction from a 70% EtOH extract of E. pekinensis root was purified by preparative reversed-phase high-performance liquid chromatography, leading to the isolation of a new ellagic acid derivative, 3,3'-di-O-methylellagic acid 4-O-(6"-O-galloyl)-ß-D-galactopyranoside (1: ), along with three known compounds, geraniin (2: ), 3,3'-di-O-methylellagic acid 4-O-ß-D-xylopyranoside (3: ), and ellagic acid 3,3'-dimethyl ether (4: ). The structure of the new compound was established by extensive spectroscopic studies and chemical evidence. The inhibitory effects of isolated compounds 1: -4: on advanced glycation end-products (AGEs) formation were examined. All compounds exhibited considerable inhibition of AGEs formation and IC50 values of 0.41 - 12.33 µM, compared with those of the positive controls aminoguanidine (IC50 = 1122.34 µM) and quercetin (IC50 = 27.80 µM). In addition, the effects of 2: and 4: on the dilation of hyaloid-retinal vessels induced by high glucose (HG) in larval zebrafish were investigated; both compounds significantly reduced the HG-induced dilation of hyaloid-retinal vessels relative to the HG-treated control group.