Inhibitory effect of fermentation byproducts on formation of advanced glycation end-products

Distilled residues (DR) of rice spirit and its derived vinegar produced a negligible inhibitory effect on advanced glycation end-products (AGE) formation. However, recycled DRs of rice spirit and barley spirit and their derived vinegars inhibited formation of N^ε(carboxymethyl)lysine (CML), a major AGE. Unlike the aforementioned DR and derived vinegars, the DR of sweet potato spirit and vinegar, contained very little protein, lysine and arginine, but they most potently inhibited CML formation. The DRs of various spirits and vinegars showed similar free radical-scavenging activities.     

Inhibitory effect of polysaccharides from pumpkin on advanced glycation end-products formation and aldose reductase activity

Inhibitors of advanced glycation end-products formation and aldose reductase have been considered to be potential treatment of diabetic complications. This study investigated the abilities of polysaccharides extracted from pumpkin (PPs) to inhibit the formation of advanced glycation end-products and aldose reductase. The results showed that the inhibitory effects of PPs on the formation of advanced glycation end-products were higher than 50%, at 200 μg/ml, stronger than the positive control aminoguanidine, and the inhibitory effects of PPs on aldose reductase were higher than 58%, at 500 μg/ml, but not as potent as the positive control epalrestat. The result of this work suggests that pumpkin polysaccharides displayed therapeutic potential in the prevention and treatment of diabetic complications.     

Investigation of pathways of advanced glycation end-products accumulation in macrophages

Advanced glycation end-products (AGE) play a role in the pathogenesis of several diseases, including diabetic complications and atherosclerosis. In atherosclerotic lesions of human aortas, AGE are localized in the extracellular matrix and intracellularly in foam cells. Two interpretations are possible for AGE accumulation inside macrophages, one is endocytic uptake of extracellular AGE-proteins by scavenger receptors; the other is intracellular AGE formation inside the macrophages. In the present study, we determined the pathways involved in AGE accumulation inside macrophages. RAW 264.7 cells, a murine macrophage cell line, incubated with BSA and 1600 mM glucose for 40 weeks, recognized heavily modified AGE- BSA. In contrast, the cells showed no ligand activity for mildly modified AGE-BSA, prepared by incubating BSA with 50 mM glucose for 24 weeks. Nepsilon-(carboxymethyl)lysine (CML)-modified proteins of about 65 kDa were detected in human monocyte-derived macrophages incubated for 7 days with 30 mM glucose and phorbol myristate acetate. Furthermore, CML was generated when glycated protein was incubated with hypochloric acid. Taken together, our results indicate that AGE detected inside foam cells in atherosclerotic lesions are generated intracellularly rather than representing endocytic uptake of extracellular AGE-proteins by scavenger receptors.     

山奈、白芷和香叶对猪肉加热过程中晚期糖化终末产物含量的影响

采用超高效液相色谱—串联质谱联用仪结合羧甲基赖氨酸(Nε-carboxymethyllysine,CML)和羧乙基赖氨酸(Nε-carboxyethyllysine,CEL)的同位素内标物作为AGEs的分析方法,研究了山奈、白芷和香叶3种食用香料的添加以及加热(100℃,5～120 min)对猪肉中结合态CML和CEL含量的影响。研究表明:加热对猪肉中AGEs的产生有促进作用,且AGEs的含量随着加热时间的延长而增加,经120min加热后的猪肉中CML和CEL的含量约为生肉的5～8倍,分别达到(35.60±2.20)～(40.68±5.66)mg/kg(CML)和(13.32±1.49)～(16.85±2.44)mg/kg(CEL)。在0～40min的加热时间过程中,加入或未加入香料的猪肉中CML[R~2=0.971～0.996;k=0.355～0.590mg/(kg·min)]和CEL[R~2=0.942～0.997;k=0.150～0.368mg/(kg·min)]的形成均符合零级反应动力学方程。香料的添加对于猪肉在加热过程中AGEs形成的影响因香料的种类、加热时间、肉的批次的不同而不同,总体来说,香料对猪肉加热过程中CML的形成影响较小,但是对CEL的形成有一定的促进作用,尤其是加热5 min处理的肉样,其CEL含量增加13%～61%。     

Detection of DNA-bound advanced glycation end-products by immunoaffinity chromatography coupled to HPLC-diode array detection

Sugars and sugar degradation products are formed during food processing, but also endogenously in vivo. In vitro, nucleosides and DNA react readily with these carbonyl compounds during the formation of the two diastereomers of N(2)-carboxyethyl-2'-deoxyguanosine (CEdG(A,B)), leading to a loss of DNA integrity. Only little is known about DNA glycation in vivo and about the influence of nutrition on CEdG formation. In this study, we developed a sensitive method to analyze DNA glycation by HPLC. For this purpose, immunoaffinity chromatography (IAC) using a polyclonal antibody against N(2)-carboxyethylguanine (CEguanine) was coupled to HPLC-DAD. In some samples, peak identity was confirmed by LC-MS/MS. The recovery of CEguanine from the IAC columns was 52.5% +/- 3.6 (n = 4). Thus, it was possible for the first time to detect CEdG(A,B), N(2)-carboxyethylguanosine (CEG(A,B)), and CEguanine in 11 human urine samples. However, due to imprecision of IAC, valid quantification of the adducts could not be achieved. Furthermore, CEdG was also detected in the DNA of cultured human smooth muscle cells (SMCs) and bovine aorta endothelium cells (BAECs). In BAECs, CEdG(A,B) were found by HPLC-DAD and LC-MS/MS after immunoaffinity purification, whereas in SMCs DNA-advanced glycation end-products were only detected with the more sensitive LC-MS/MS method.     

Effect of combined UV-thermosonication and Ecklonia cava extract on advanced glycation end-products in soymilk

Thermal treatment is used to inactivate microbes in soymilk, but it increases the amount of advanced glycation end products (AGEs). Therefore, this study examined if ultraviolet light with thermo-sonication (UVTS) and Ecklonia cava extract (EX) could provide an alternative process to prevent AGEs formation in processed soymilk. A coiled tube UV reactor was used simultaneously with an ultrasonic generator for UVTS treatment, while an autoclave was employed for thermal treatment. UVTS treatment was examined at different temperatures and flow rates to achieve a 5-log reduction of pre-inoculated Escherichia coli and Salmonella typhimurium in soymilk. After confirming EX's anti-glycation effects against fructosamine, ɑ-dicarbonyl compounds, protein carbonyl content, and AGEs formation, it was added to soymilk before the UVTS. The ɑ-dicarbonyl compounds (glyoxal and methylglyoxal) and AGEs (N^ε-(1-carboxymethyl)-l -lysine [CML] and N^ε-(1-carboxyethyl)-l -lysine [CEL]) in soymilk increased after autoclaving (AC). Compared with AC, the UVTS with .05% EX decreased glyoxal, methylglyoxal, CML, and CEL by 78%, 82%, 32%, and 59%, respectively. These results indicated that UVTS with EX could be an alternative pasteurization process for soymilk that minimizes AGEs formation.     

大黄素对食品模型中晚期糖基化终产物的抑制作用

通过建立L-赖氨酸-葡萄糖(Lys-Glc)反应体系,以大黄素作为抑制剂,利用NBT还原法、紫外分光光度法、高效液相色谱法及荧光分光光度法分别研究大黄素对果糖胺、乙二醛(GO)、5-羟甲基糠醛(5-HMF)、类黑精、羧甲基赖氨酸(CML)及荧光性AGEs和戊糖素的抑制作用。结果表明:大黄素对氧化产物及由氧化产物进一步生成的中、末期产物GO、CML、类黑素有较好的抑制作用,对果糖胺、5-HMF有一定的抑制作用。大黄素对戊糖素、荧光性AGEs无明显抑制作用,延迟其产生。可见大黄素作为一种蒽醌类物质,对糖基化反应中氧化产物的抑制作用与其抗氧化性有关。     

Inhibitory efficacy of Ligularia fischeri against aldose reductase and advanced glycation end products formation

The efficacy of Ligularia fischeri (LF) for managing diabetic complications was evaluated by assessing inhibitory effects against advanced glycation end product (AGE) formation, rat lens aldose reductase (RLAR), and 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging. The ethyl acetate fraction from 70% ethanol extracts of LF showed the highest DPPH radical scavenging activity of 53.90% at a concentration of 3.3 μg/mL. The ethyl acetate fraction exhibited the most potent AGE formation inhibition of 73.57% at a concentration of 55 μg/mL and showed the most potent RLAR inhibition of 88.97% at a concentration of 11.11 μg/mL. The ethyl acetate fraction exhibited the most potent antioxidant and anti-diabetic effects. Nuclear magnetic resonance via bioactivity-guided fractionation of the LF ethyl acetate fraction revealed that 3,4-dicaffeoylquinic acid was the bioactive compound. This compound from LF can be effective for prevention or treatment of diabetic complications.     

Inhibition of advanced glycation endproduct formation by foodstuffs

The Maillard reaction, which is generally termed nonenzymatic browning or glycation, has been implicated in accelerated aging and diabetic complications in vivo. Although the molecular basis of glycation-induced pathogenesis is not well understood, the following have been noted: (1) protein glycation leads to the formation and accumulation of toxic advanced glycation endproducts (AGEs); (2) AGEs can permanently alter the structure and function of body proteins; and (3) the interaction between AGE-modified proteins and AGE-specific receptors (RAGEs) on the cell surface induces the overproduction of reactive oxygen species (ROSs) and inflammatory mediators, which leads to cellular disorders in biological systems. To date, studies that have examined the contribution of protein glycation to disease-states have primarily focused on the deleterious effects and related mechanisms of these glycotoxins. However, it remains unknown whether phytochemicals exert protective effects against glycotoxin-induced damage. Thus, the development and investigation of AGE inhibitors, especially the natural anti-AGE agents without adverse effects, may provide a therapeutic approach for delaying and preventing premature aging and diabetic complications. In this review, we provide an outline of anti-glycation properties of foodstuffs and/or their active components, and discuss their mechanisms of action.     

Evaluation of the in vitro inhibitory effects of buckwheat enhanced wheat bread extracts on the formation of advanced glycation end-products (AGEs)

In this study, the inhibitory effects of extracts from buckwheat enhanced wheat breads, on the formation of fluorescent advanced glycation end-products (AGEs) were studied in bovine serum albumin (BSA)/glucose and BSA/methylglyoxal (MGO) systems. Correlations with total phenolic compounds (TPC), total flavonoids (TF) as well as rutin (Ru) and quercetin (Q) contents were also identified.     

Inhibition of the formation of advanced glycation end products by thymoquinone

The inhibitory activity of thymoquinone, a major quinone from black seeds (Nigella sativa) against the formation of advanced glycation end products was studied using the hemoglobin-δ-gluconolactone, human serum albumin–glucose, and the N-acetyl-glycyl-lysine methyl ester–ribose assays. A comparison was made with the inhibitory activity of aminoguanidine. The cytotoxicity of thymoquinone was studied by the release of lactate dehydrogenase from platelets and the levels of plasma thiols. At 20 μM, thymoquinone inhibited 39% of hemoglobin glycation, 82% of post-Amadori glycation products, reduced methyglyoxal-mediated human serum albumin glycation by 68%, inhibited 78% of late glycation end products. Aminoguanidine at 10 mM was less effective than thymoquinone. The IC₅₀ for thymoquinone and aminoguanidine were 7.2 μM and 1.25 mM, respectively. Thymoquinone at 20–50 μM was not toxic to platelet lactate dehydrogenase and plasma thiols. The potential of thymoquinone in food applications is discussed.     

Naturally occurring contamination in the Mancos Shale

Some uranium mill tailings disposal cells were constructed on dark-gray shale of the Upper Cretaceous Mancos Shale. Shale of this formation contains contaminants similar to those in mill tailings. To establish the contributions derived from the Mancos, we sampled 51 locations in Colorado, New Mexico, and Utah. Many of the groundwater samples were saline with nitrate, selenium, and uranium concentrations commonly exceeding 250,?000, 1000, and 200 μg/L, respectively. Higher concentrations were limited to groundwater associated with shale beds, but were not correlated with geographic area, stratigraphic position, or source of water. The elevated concentrations suggest that naturally occurring contamination should be considered when evaluating groundwater cleanup levels. At several locations, seep water was yellow or red, caused in part by dissolved organic carbon concentrations up to 280 mg/L. Most seeps had (234)U to (238)U activity ratios greater than 2, indicating preferential leaching of (234)U. Seeps were slightly enriched in (18)O relative to the meteoric water line, indicating limited evaporation. Conceptually, major ion chemical reactions are dominated by calcite dissolution following proton release from pyrite oxidation and subsequent exchange by calcium for sodium residing on clay mineral exchange sites. Contaminants are likely released from organic matter and mineral surfaces during weathering.     

基于蛋白沉淀法超高效液相色谱-串联质谱法检测面包中两种蛋白结合型晚期糖基化终末产物

目的 建立面包中两种典型晚期糖基化终末产物（AGEs）的超高效液相色谱-串联质谱检测方法。方法以结合型羧甲基赖氨酸（CML）和羧乙基赖氨酸（CEL）为检测对象,面包样品经还原孵育、蛋白沉淀、加同位素内标、酸水解、氮吹、九氟戊酸水溶液复溶后,多反应监测定性及定量分析。结果 方法的检出限CML为4.5 ng/g,CEL为0.5 ng/g;定量限CML为20 ng/g,CEL为2 ng/g;CML加标回收率为89.62%～95.65%,CEL的加标回收率为86.38%～97.17%;标准曲线线性范围为CML2.5～800 ng/mL和CEL0.25～80 ng/mL,决定系数均大于0.999。结论 该方法准确且灵敏,能够满足面包中AGEs的检测需求。     

Evidence against dietary advanced glycation endproducts being a risk to human health

In vivo, advanced glycation endproducts (AGEs) are linked to various diseases, particularly those associated with diabetes. AGEs are also formed when many foods are thermally processed. The extent to which dietary AGEs are absorbed by the gastrointestinal (GI) tract and their possible role in the onset and promotion of disease are currently of considerable interest. This paper reviews information that supports the argument that dietary AGEs are not a risk to human health.     

Inhibitory effects of microalgal extracts on the formation of advanced glycation endproducts (AGEs)

The antiglycative activities of 20 microalgae at different growth phases were evaluated for the first time. In a bovine serum albumin (BSA)-glucose system, ethyl acetate fractions of green microalgae Chlorella and diatom Nitzschia laevis exhibited the highest inhibitory effects against the formation of total advanced glycation endproducts (AGEs) (inhibition rates: 81.76–88.02% and 91.68%) at the concentration of 500 ppm. Such abilities were higher than the effect of 1 mM aminoguanidine (AG) solution (inhibition rate: 80.51%), a commonly used inhibitor of glycation process. In addition to total AGEs, these fractions were also found to be effective in the blockage of the formation of two specific AGEs, pentosidine and N^ε-Carboxymethyllysine (CML). Different from many other plant species, AGE inhibitory abilities of selected microalgae were not due to the presence of phenolic compounds. HPLC and gas chromatography (GC) analysis revealed that carotenoids in Chlorella and unsaturated fatty acids, mainly of linoleic acid, arachidonic acid and eicosapentaenoic acid in Nitzschia laevis contributed to their strong antiglycative capacities.     

Curcumin against advanced glycation end products (AGEs) and AGEs-induced detrimental agents

Objectives: This study was aimed to review and collate effects of curcumin on generation of advanced glycation end products (AGEs) and AGEs induced detrimental agents.Methods: Pubmed, Googlescholar, ScienceDirect, and Scopus databases were searched. Searching was not limited to specific publication period. Only English language original articles (in vitro, experimental and human) which had examined the effect of curcumin on AGEs formation and AGEs induced apoptosis, oxidative stress or inflammatory responses were included. To review effect of curcumin on AGEs formation, search terms were as following: ‘‘curcumin” (title) and AGEs or pentosidine or methylglyoxal or carboxymethyllysine or glucosylation (title/abstract). Totally 104 articles were searched which 19 were selected for review. To review effect of curcumin on AGEs induced harmful agents, key words were as following: “curcumin” (title) and AGEs (title/abstract) and apoptosis or oxidative stress or DNA damage or cell injury or inflammatory or cell death or cell proliferation (title/abstract). Totally 126 articles were searched which 18 were found appropriate for review.Results: Regarding curcumin and AGEs formation, ten eligible articles (1 human trial, 5 animal models and 4 in vitro) and with regarding curcumin and AGEs-induced complications, 17 articles (5 on apoptosis, 9 on oxidative stress, and 3 on inflammatory responses) were selected. Except one, all studies indicated that curcumin is able to prevent AGEs formation and AGEs-induced disturbances with different potential mechanisms.Conclusion: Curcumin can inhibit AGEs formation and AGEs-induced disturbances. More RCT researches are suggested to evaluate beneficial effect of curcumin regarding AGEs in different age-related chronic diseases, with specific attention to AGEs memberships.     

Inhibitory effects of Chrysanthemum species extracts on formation of advanced glycation end products

The corolla of Chrysanthemum species (C.morifolium R. and C.indicum L.) has long been used to treat eye and inflammatory disease. However, little is known about the antiglycation properties of Chrysanthemum species. Our study sought to characterise their activity against the formation of advanced glycation end products (AGEs) in glycation model reactions. In BSA/glucose (fructose) systems, both Chrysanthemum species strongly inhibited the formation of AGEs and N^ε-(carboxymethyl)lysine (CML). C.morifolium R., not C.indicum L., also acted to inhibit the formation of fluorescent AGEs, including pentosidine. This difference correlated with the values of polyphenol and flavonoid components. We characterised the active components in these plants by liquid chromatography-diode array detector-atmospheric pressure chemical ionisation/mass spectrometry, which showed that C. morifolium R. contains large amounts of chlorogenic acid, flavonoid glucoside varieties, and apigenin, while C.indicum L. contains large amounts of caffeic acid, luteolin, and kaempferol. Our findings raise hopes for the successful treatment of pathogenesis in conditions associated with diabetic complications and aging.     

Naturally occurring mastitis disrupts developmental competence of bovine oocytes

We examined the effects of naturally occurring mastitis on bovine oocyte developmental competence in vitro. Specifically, we investigated the effects of intramammary infection on the ovarian pool of oocytes (i.e., follicle-enclosed oocytes) and their ability to undergo in vitro maturation, fertilization, and further development to the blastocyst stage. Culled Holstein cows (n = 50) from 9 commercial dairy farms in Israel were allotted to 3 groups according to somatic cell count (SCC) records of the last 3 monthly milk tests as well as of quarter samples collected before slaughter: (1) low SCC (n = 7), (2) medium SCC (n = 16), or (3) high SCC (n = 27). Means of SCC values differed among low-, medium-, and high-SCC groups: 148,000, 311,000 and 1,813,000 cell/mL milk, respectively. Milk yield and days in milk did not differ among the 3 groups. Bacterial isolates included coagulase-negative staphylococci, Escherichia coli, Streptococcus dysgalactiae, or no bacteria found. Ovaries were collected at the abattoir and brought to the laboratory. Cumulus oocyte complexes were recovered separately from each cow and subjected individually to in vitro maturation and fertilization, followed by 8 d in culture. The number of aspirated oocytes did not differ among groups, with a range of 17 to 21 oocytes per cow. The proportion of oocytes that cleaved into 2- to 4-cell-stage embryos (86.1 ± 3.4%) did not differ among groups. In contrast, mean percentages of embryos developed to the blastocyst stage on d 7 and 8 after fertilization were less in both medium- and-high SCC groups than in the low-SCC group (5.6 ± 2.3 and 4.1 ± 1.8 vs. 18.1 ± 4.6%, respectively). Additional analysis indicated that cleavage and blastocyst-formation rates did not differ among the bacterial types in the low-, medium-, and high-SCC groups. These are the first results to demonstrate that naturally occurring mastitis disrupts the developmental competence of the ovarian pool of oocytes, (i.e., oocytes at the germinal vesicle stage). The disruption was associated with elevation of SCC rather than bacterial type. The results may provide a partial explanation for the low fertility of cows that have contracted mastitic pathogens before insemination.