Amounts Of Methylglyoxal Research Articles

Investigation of formation of AGEs precursors, hydroxymethylfurfural and malondialdehyde in oleogel added cakes using an in vitro simulated gastrointestinal digestive system

The baking process has the potential to generate health-risk compounds, including products from lipid oxidation and Maillard reaction. Pre- and post-digestion levels of hydroxymethylfurfural (HMF), malondialdehyde (MDA), glyoxal (GO), and methylglyoxal (MGO) were studied in cakes formulated with hazelnut and sunflower oil, along with their oleogels as margarine substitutes. The concentration of HMF in oil and oleogel-formulated cakes increased after digestion compared to cakes formulated with margarine. The MDA values were between 82 and 120 μg/100 g in oil and oleogel formulated cakes before digestion and a decrease was observed after digestion. The substitution of margarine with oil and oleogels resulted in the production of high amounts of GO and MGO in cakes. However, the highest bioaccessibility as 318.2% was found in cakes formulated by margarine for GO. Oleogels may not pose a potential health benefit compared to margarines due to the formation of HMF, MDA, GO, and MGO.

Butyrate increases methylglyoxal production through regulation of the JAK2/Stat3/Nrf2/Glo1 pathway in castration‑resistant prostate cancer cells.

Cancer cells are characterized by increased glycolysis, known as the Warburg effect, which leads to increased production of cytotoxic methylglyoxal (MGO) and apoptotic cell death. Cancer cells often activate the protective nuclear factor erythroid 2‑related factor2 (Nrf2)/glyoxalase1 (Glo1) system to detoxify MGO. The effects of sodium butyrate (NaB), a product of gut microbiota, on Nrf2/Glos/MGO pathway and the underlying mechanisms in prostate cancer (PCa) cells were investigated in the present study. Treatment with NaB induced the cell death and reduced the proliferation of PCa cells (DU145 and LNCap). Moreover, the protein kinase RNA-like endoplasmic reticulum kinase/Nrf2/Glo1 pathway was greatly inhibited by NaB, thereby accumulating MGO-derived adduct hydroimidazolone (MG-H1). In response to a high amount of MGO, the expression of Nrf2 and Glo1 was attenuated, coinciding with an increased cellular death. NaB also markedly inhibited the Janus kinase 2 (JAK2)/Signal transducer and activator of transcription 3 (Stat3) pathway. Conversely, co‑treatment with Colivelin, a Stat3 activator, significantly reversed the effects of NaB on Glo1 expression, MG-H1 production, and the cell migration and viability. As expected, overexpression of Stat3 or Glo1 reduced NaB‑induced cell death. The activation of calcium/calmodulin dependent protein kinase II gamma and reactive oxygen species production also contributed to the anticancer effect of NaB. The present study, for the first time, demonstrated that NaB greatly increases MGO production through suppression of the JAK2/Stat3/Nrf2/Glo1 pathway in DU145 cells, a cell line mimicking castration‑resistant PCa (CRPC), suggesting that NaB may be a potential agent for PCa therapy.

Assessment of formation of the Glyoxal and Methylglyoxal Levels in Various Sugar-Free or Sweetened Products under in Vitro Gastrointestinal Digestive System

This study aimed to determine the formation of glyoxal (GO) and methylglyoxal (MGO) in various sweetener-containing products under in vitro digestion. Products obtained from different markets in Istanbul, Turkey. The amount of GO and MGO was determined by High-Performance Liquid Chromatography using pre-column derivatization. Initial GO and MGO values were ranged between 21.1-234.4 µg/100 g and 109.7-3164.5 µg/100 g for GO and MGO respectively. After digestion formation of GO and MGO were increased up to 2546% and 607.9%, respectively. Biscuit sample had the highest GO and MGO values, whereas, after digestion, the wafer exhibited the highest formation rate; both result may be related to high fat content, low moisture and, high heat treatment. Our results revealed that sweetener-containing products such as diabetic jams, chocolate, candy, had high GO and MGO content and this content may increase with digestion. Further studies examining the effects of different sugar types on GO and MGO formation are needed.

Betaine postpones hyperglycemia-related senescence in ovarian and testicular cells: Involvement of RAGE and β-galactosidase.

The structural and functional disorders of the testis and ovary are one of the main complications of hyperglycemia. Betaine is a trimethyl glycine with antioxidant, antidiabetic, and anti-inflammatory potential. The aim of this study is to investigate the potential of betaine on the expression of aging and oxidative stress markers in ovarian and testicular cells under hyperglycemic conditions. Testicular and ovarian cells were subjected to four different conditions, including normal glucose and hyperglycemia, with or without betaine (5 mM). The cells with hyperglycemia saw an increase in malondialdehyde (MDA), methylglyoxal (MGO), expression of a receptor for AGE, and aging-related genes (β-GAL), and a decrease in the activity of antioxidant enzymes including catalase, glutathione peroxidase, and superoxide dismutase. The treatment with betaine, in contrast, decreased the amount of MGO and MDA, and also downregulated aging-related signaling. Although hyperglycemia induces senescence in testicular and ovarian cells, the use of betaine may have a protective effect against the cell senescence, which may be useful in the management of infertility.

Determination of α-oxo-aldehydes and furfurals using HPLC-PDA-ELSD method in sugar-containing food products

Four food toxins, α-oxo-aldehydes (glyoxal and Methylglyoxal) and furfurals (furfural and 5-hydroxymethlfurfural) were simultaneously retained on a Phenomenex Luna phenyl hexyl column (150×4.6mm×5 µm,100 Å) using ammonium acetate / acetonitrile (28:72, v/v) as mobile phase at 1 mL/min. The detector setting was tuned at 280 nm to quantify furfurals, whereas α-oxo-aldehydes were quantified using Evaporating light scattering detector (ELSD). The extraction of selected analytes from aqueous and lipid-based media was optimized using liquid-liquid extraction (LLE) method. A sum of 24 different brands (n = 20 in each group) of glucose containing preparations were collected, extracted, and screened for the presence of selected analytes. The observed level of selected analytes was divided into non-detectable, moderately high and above limit samples. The machine learning model viz. decision tree and multilayer perceptron models was optimized and validated for correlation of selected dependent variables with independent variables. The occurrence of 5-HMF depended on state and age of sample, whereas sugar concentration was responsible for furfural presence. The samples with higher 5-HMF levels were categorized as being viscous/semisolid and were preserved with potassium sorbate. About 77.3 % of the 480 samples studied indicated a considerable amount of methylglyoxal, and the food colors were classed as responsible for development of it followed by mixed fruit flavor and vanilla taste flavor as food additives.

Formation of Protein-Bound Maillard Reaction Products during the Storage of Manuka Honey.

Honey from the nectar of the Manuka tree (Leptospermum scoparium) grown in New Zealand contains high amounts of antibacterial methylglyoxal (MGO). MGO can react with proteins to form peptide-bound Maillard reaction products (MRPs) such as Nε-carboxyethyllysine (CEL) and "methylglyoxal-derived hydroimidazolone 1" (MG-H1). To study the reactions of MGO with honey proteins during storage, three manuka honeys with varying amounts of MGO and a kanuka honey (Kunzea ericoides) spiked with various MGO concentrations up to 700 mg/kg have been stored at 37 °C for 10 weeks, and the formation of protein-bound MRPs has been analyzed via high-performance liquid chromatography-mass spectrometry (HPLC-MS/MS) following isolation of the protein fraction and enzymatic hydrolysis. During storage, contents of protein-bound CEL and MG-H1 increased continuously, directly depending on the MGO content. For honeys with large amounts of MGO, a slower formation of Nε-fructosyllysine (FL) was observed, indicating competing reactions of glucose and MGO with lysine. Furthermore, the lysine modification increased with storage independently from the MGO concentration. Up to 58-61% of the observed lysine modification was explainable with the formation of CEL and FL, indicating that other reactions, most likely the formation of Heyns products from lysine and fructose, may play an important role. Our results can contribute to the authentication of manuka honey.

3-Phenyllactic Acid and Polyphenols Are Substances Enhancing the Antibacterial Effect of Methylglyoxal in Manuka Honey

Manuka honey is known for its unique antibacterial activity, which is due to methylglyoxal (MGO). After establishing a suitable assay for measuring the bacteriostatic effect in a liquid culture with a time dependent and continuous measurement of the optical density, we were able to show that honey differs in its growth retardingeffect on Bacillus subtilis despite the same content of MGO, indicating the presence of potentially synergistic compounds. In model studies using artificial honey with varying amounts of MGO and 3-phenyllactic acid (3-PLA), it was shown that 3-PLA in concentrations above 500 mg/kg enhances the bacteriostatic effect of the model honeys containing 250 mg/kg MGO or more. It has been shown that the effect correlates with the contents of 3-PLA and polyphenols in commercial manuka honey samples. Additionally, yet unknown substances further enhance the antibacterial effect of MGO in manuka honey. The results contribute to the understanding of the antibacterial effect of MGO in honey.

BIOACCESSIBILITY OF ?-DICARBONYL COMPOUNDS IN BREADS AND OTHER BAKERY PRODUCTS USING AN IN VITRO STIMULATED GASTROINTESTINAL DIGESTIVE SYSTEMS

Digestive system conditions may increase or decrease the formation ?-dicarbonyl compounds. This study aims to determine the bioaccessibility of glyoxal (GO) and methylglyoxal (MGO) in bakery products under in vitro gastrointestinal conditions. For this purpose breads and bakery products were obtained from bakehouse in Istanbul, Turkey. The amount of GO and MGO in samples ranged between 54.8 to 180.4 µg /100 g and 45.8 to 220.3 µg / 100g respectively. After in vitro digestion GO and MGO levels were increased to between 170.4 to 656.8 µg / 100g and 105.6 to 1220.9 µg/100 g, respectively. Bioaccessibility of GO and MGO increased up to 727% and 1351% respectively. High increase rates were observed in samples that contain high fat and low moisture contents. We demonstrated that formation of GO and MGO increase under in vitro digestive system conditions. Further studies are needed to extensively investigate the formation mechanism in such foods.

Investigation of in vitro formation of advanced lipoxidation end products and advanced glycation end products precursors in high-fat processed meat products

The precursors glyoxal (GO) and methylglyoxal (MGO) of advanced glycation end products (AGEs) or advanced lipoxidation end products (ALEs) occur exogenously and endogenously. These α-dicarbonyl compounds, GO and MGO, can be formed from Maillard reactions during food processing as well as protein and lipid peroxidation. The purpose of the present study was to determine and evaluate the in vitro formation of AGEs and ALEs precursors, GO and MGO, in high-fat processed meat products. Before digestion, GO and MGO amounts in the samples ranged between 59.0 and 81.0 µg/100 g and between 11.7 and 47.0 µg/100 g, respectively. After in vitro digestion, GO and MGO formation ranged between 147.0 and 514.1% and 156.0 and 6912.3%, respectively. It is believed that prooxidant components, such as oxygen, enzymes, or heme-proteins, in the gastrointestinal tract promote lipid oxidation; therefore, GO and MGO can be formed. A higher rate of MGO increase was observed in starch containing meatball (chicken) and nugget samples in the gastrointestinal tract. It is thought that the carbohydrates in the meat samples may have contributed to the amount of GO and MGO formed. Thus, reducing fat and starch may produce low levels of GO and MGO formation in the foods during processing or digestion.

Determination and assessment of the most potent precursors of advanced glycation end products in baklava and Turkish delight by HPLC

This study aims to investigate the glyoxal (GO), and methylglyoxal (MGO), and the effect of the types of sugar components on GO and MGO formation in Turkish delight and baklava. The values of GO and MGO ranged from 326 to 1842 µg/100 g, and from 31 to 517 µg/100 g in Turkish delight, respectively. The values of GO and MGO in baklava ranged from 344 to 815 µg/100 g, and between 19 and 358 µg/100 g, respectively. One of the baklava samples may contained high fructose corn syrup (HCFS) given the presence of significantly higher amount of MGO than that of other samples. Increased sugar concentration, processing time, storage, and HCFS in Turkish delight and baklava may affect the GO and MGO formations. Longer storage time may influence the increase of MGO formation in Turkish delight. Therefore, these products should be consumed less or formulated with agents that reduce AGEs.

Effects of Different Herbal Teas on Reducing the Bioaccessibility of Methylglyoxal in Crackers under Stimulated Gastrointestinal Digestive System

The present study aims to determine the bioaccessibility of methylglyoxal (MGO) in crackers and investigate the effects of herbal teas on reducing the formation of MGO under in vitro digestion system. Different herbal teas were added in crackers to reduce MGO formation under in vitro system. MGO levels were determined by High-Performance Liquid Chromatography. The amounts of MGO in crackers samples at initial and after in vitro digestion were ranged from 51 to 104 µg/100 g and 274 to 408 µg / 100 g, respectively. After in vitro digestion, the bioaccessibility of MGO values was increased up to 628%. Also, it was found that polyphenol-rich herbal teas such as black, green, turmeric, and rosehip significantly reduced MGO bioaccessibility in crackers. The addition of these herbal teas as antioxidants in cracker formulations or consumption of herbal teas along with snack foods may be recommended.

Investigation of the α-Dicarbonyl Compounds in Some Snack Foods by HPLC Using Precolumn Derivatization with 4-Nitro-1,2-Phenylenediamine

Snack foods are widely consumed in today's modern diet. Food processing techniques and food composition may increase advanced glycation products (AGEs) in snack foods. The present study aimed to determine the most potent precursors of AGEs in snack foods. For this purpose, commonly consumed some snacks foods were obtained from markets in Istanbul, Turkey. The amount of α dicarbonyl compounds (α-DCs,) glyoxal (GO), and methylglyoxal (MGO) were determined by high-performance liquid chromatography. The measured amount of GO and MGO ranged between 4-684 µg / 100 g and 28-1573 µg / 100 g in snack foods, respectively. In our study, high levels of MGO were detected in wafer hazelnut chips with cheese and peanuts. Due to their high-fat content, the formation of GO and MGO may occur through lipid peroxidation. In addition, the fragmented state of hazelnuts and peanuts in samples may increase lipid peroxidation. Free sugar content in Turkish delight and cake with fruit might contribute to the α-DCs formation by caramelization reaction due to high temperature. In conclusion, snack products that are frequently consumed have many unfavorable features for health. It is important to limit snack food consumption in terms of reducing AGEs exposure.

Inhibitory Activity on the Formation of Reactive Carbonyl Species in Edible Oil by Synthetic Polyphenol Antioxidants.

Food lipids play an important role in food quality, and their attributes contribute to texture, flavor, and nutrition. However, high-temperature processing leads to lipid peroxidation, degradation, and the formation of reactive carbonyl species (RCS), such as acrolein (ACR), glyoxal (GO), and methylglyoxal (MGO). We investigated the changes in the peroxidation value (POV), Rancimat induction time, formation and total amount of RCS, and inhibitory effects of synthetic polyphenol antioxidants on ACR/GO/MGO in plant oils during heating processing through an accelerated oxidation test using Rancimat. With increasing temperature and heating time, the amounts of ACR, GO, and MGO in oil increased and the level of ACR was about several times higher than that of GO and MGO. We also found that some amounts of ACR, GO, and MGO were produced at the initial stage before reaching the peak value of POV, even before oil oxidative rancidity, and the common antioxidant butyl hydroxyanisole (BHA)/butylated hydroxytoluene (BHT) could not remove them once they were generated. This is first time to purify PG-ACR-MGO and elucidate the structure based on analysis of their high resolution mass spectrometry and 1H, 13C, and two-dimensional nuclear magnetic resonance. We further found that PG rather than BHT and BHA efficiently trapped ACR, OG, and MGO to form adducts in oil and roasted beef burgers with corn oil. Additionally, after incubation at 80 °C, the trapping order of PG was as follows: ACR, MGO, and GO, and the adduct of PG-ACR was formed within 1 min; after 10 min, PG-MGO was generated; and three adducts formed at 15 min. However, PG could not trap ACR, GO, or MGO to form adducts at room temperature. This study provided novel knowledge to advance our understanding of the ability of synthetic polyphenol antioxidants to scavenge RCS simultaneously, such as ACR, MGO, and GO. Our findings demonstrated that PG, as an inhibitor of RCS, is suitable for medium- and high-temperature food processing but not for normal-temperature storage.

Methylglyoxal (MGO) in Italian Honey

Methylglyoxal (MGO) is recognized as being the bioactive component responsible for the antibacterial activity of mānuka honey. MGO content was investigated by high-performance liquid chromatography (HPLC-UV), in isocratic elution, to assess the occurrence of this compound in mono- and multi-floral honey samples representative of different botanical and geographic origins in Italy. Specifically, 110 honey samples from sweet cherry tree (Prunus avium L.), thyme (Thymus vulgaris L.), almond tree (Prunus amygdalus L.), eucalyptus (Eucalyptus camaldulensis L.), coriander (Coriandrum sativum L.), cornflower (Centaurea cyanus L.), thistle (Silybum marianum L.), acacia (Robinia pseudoacacia L.), citrus, honeydew and multifloral honey were considered. The amount of MGO found in different types of honey was ranging from 0.4 to 24.1 mg/kg. This study provides, for the first time, data on MGO levels in Italian cherry and almond honey, which showed higher concentrations of MGO compared to honeys from other botanical species.

Effects of different cooking methods on methylglyoxal scavenging potential of meat under simulated gastrointestinal conditions

This study aimed at investigating the effects of different cooking methods on methylglyoxal scavenging potential of cooked meats under simulated gastrointestinal conditions. Grilling and sous vide cooking were chosen as representative cooking techniques for high temperature short time and low temperature long time heating, respectively. Beef and chicken meat were grilled and sous vide cooked at different degrees of doneness. The samples were subjected to simulated gastric and intestinal digestion with methylglyoxal. Significant reductions (p < 0.05) exceeding 50% in the amounts of methylglyoxal were determined in the presence of meat samples under intestinal conditions. Comparing to raw meat, grilling and mincing were found to decrease significantly (p < 0.05) methylglyoxal scavenging potential of beef samples. However, no difference (p > 0.05) was observed in methylglyoxal scavenging potential of beef and chicken meats after sous vide cooking. Among the compositional factors (thiol groups, free amino groups, creatine, arginine, and lysine), creatine was found as the most significant methylglyoxal scavenger in raw and grilled beef under intestinal conditions.

Determination of the most potent precursors of advanced glycation end products in some high‐sugar containing traditional foods using high‐performance liquid chromatography

The aim of this research was to investigate the levels of the most potent precursors of advanced glycation end products (AGEs) in some high-sugar containing Turkish traditional foods and investigated the effects of sugar content on the formation of AGE precursors. The amounts of glyoxal (GO) and methylglyoxal (MGO) were determined by HPLC using pre-column derivatization. When we evaluated GO and MGO results, GO and MGO values ranged from 99.8 to 223.3, and from 53.2 to 8,773.7 µg/100 g, respectively. GO and MGO may be formed by Maillard reactions as well as caramelization reactions. Products made with red fruits contained low MGO amounts. Thus, traditional foods containing red fruit may prevent the formation of GO and MGO. In general, we concluded that foods containing proanthocyanidins are more effective in reducing the MGO level than foods containing resveratrol. Further studies are needed to support these results. Practical applications Fruit-based and heat-treated traditional foods examined in this study contain high amounts of sugar. The precursors of advanced glycation end products, glyoxal (GO), and methylglyoxal (MGO) may be formed by the Maillard reactions as well as the caramelization reaction in the examined samples. Pestil, sausage, and molasses are products that can be stored for a long time. Therefore, longer storage may also contribute to the increasing amount of GO and MGO. Products made from red fruits contain high amounts of anthocyanins, whereas products made with grape contain high amounts of resveratrol. Products made with red fruits contain low amounts of MGO. In general, foods containing proanthocyanidins are more effective in reducing the MGO level than foods containing resveratrol.

Oxidative Formation of Methylglyoxal in Glycerol Preparations during Storage.

Methylglyoxal (MGO) is a reactive α-dicarbonyl compound that causes carbonylation of protein and DNA through the pathways of the Maillard reaction. It is known that MGO is physiologically involved in renal dysfunction, vascular disorders, and the acceleration of aging. In this study, we showed for the first time, that a trace amount of MGO was present as an impurity in glycerol preparations used as external medicines and intravenous infusions, when kept unused. The concentration of MGO in the glycerol solutions, diluted to a concentration of 20%, significantly increased after storage for one month when compared to the MGO concentration immediately after opening. Following storage for 6 months at 25°C, MGO concentration increased by about 300 times (approx. 170 µM), and at 40°C, it increased by about 600 times (approx. 350 µM). In the case of intravenous infusion preparations containing 10% glycerol, the MGO concentration increased by 4-15 times (approx. 70 µM) after 2 months of storage at 40°C, and reached over 200 µM after 6 months. Results from the present study showed that glycerol in pharmaceutical preparations is gradually oxidized to form MGO via autoxidation, depending on the temperature and dissolved oxygen content. Thus, we suggest that precautions should be taken when storing glycerol preparations in bottles or plastic containers, with respect to the storage temperature and sealability to prevent MGO formation due to oxidation of glycerol.

Studies on the Formation of 3-Deoxyglucosone- and Methylglyoxal-Derived Hydroimidazolones of Creatine during Heat Treatment of Meat.

Dicarbonyl compounds such as methylglyoxal (MGO) and 3-deoxyglucosone (3-DG) are formed via caramelization and the Maillard reaction in food during heating or in vivo as byproducts of glycolysis. Recently, it was shown that creatine, an amino compound linked to the energy metabolism in vertebrate muscle, reacts rapidly with methylglyoxal under physiological conditions to form N-(4-methyl-5-oxo-1-imidazolin-2-yl)sarcosine (MG-HCr), a methylglyoxal-derived hydroimidazolone of creatine. Based on the observation that heated meat contains only small amounts of MGO and 3-DG when compared to many other foodstuffs, the aim of this study was to investigate a possible reaction of creatine with 3-DG and MGO in meat. From incubation mixtures consisting of 3-DG and creatine, a new hydroimidazolone of creatine, namely N-(4-butyl-1,2,3-triol-5-oxo-1-imidazolin-2-yl)sarcosine (3-DG-HCr), was isolated and characterized via spectroscopic means. To quantitate 3-DG-HCr and MG-HCr, meat and fish products were analyzed via HPLC-MS/MS using isotopically labeled standard material. Whereas samples of raw fish and meat contained only trace amounts of the hydroimidazolones (below 5 μg/kg), up to 28.3 mg/kg MG-HCr and up to 15.3 mg/kg 3-DG-HCr were found in meat and fish products. The concentrations were dependent on the heat treatment and presumably on the smoking process. In comparison to the lysine and arginine derivatives CEL, pyrraline, and MG-H1, the derivatization rate of creatine as MG-HCr and 3-DG-HCr was higher than of lysine and arginine, which clearly demonstrates the 1,2-dicarbonyl scavenging properties of creatine in meat.

Adducts formed during protein digestion decreased the toxicity of five carbonyl compounds against Caco-2 cells.

Acrolein (ACR), glyoxal (GO), methylglyoxal (MGO), hydroxymethylfurfural (HMF), and malondialdehyde (MDA) are toxic contaminants for humans. This work aimed to investigate whether intake of proteins can mitigate their toxicity. Simulated gastrointestinal digestion of proteins from pork, chicken, milk powder and soy protein isolate eliminated amount of ACR, GO, MGO, HMF, and MDA. Among six amino acids, cysteine showed highest capacity for elimination of these toxic compounds through the formation of adducts; it reached the highest elimination capacity for GO, MGO, ACR, MDA, and HMF in 40 min at pH 2.0, and 20 min at pH 7.0. The formed adducts between cysteine and GO, MGO, or ACR showed much lower toxicity against Caco-2 cells. Incubation of the cells with 8 mM GO and MGO for 48 h decreased the cell viability to 16.1%, 16.9% respectively; while incubation of the same concentration of their adducts still kept the cell viability at 82.2% and 81.6% respectively. Cysteine showed much higher detoxifying capacity for ACR than GO and MGO, which can lower the toxicity of ACR toward Caco-2 cells by 80 times.

Tannerella forsythia‐produced methylglyoxal causes accumulation of advanced glycation endproducts to trigger cytokine secretion in human monocytes

The periodontal pathogen Tannerella forsythia has the unique ability to produce methylglyoxal (MGO), an electrophilic compound which can covalently modify amino acid side chains and generate inflammatory adducts known as advanced glycation endproducts (AGEs). In periodontitis, concentrations of MGO in gingival-crevicular fluid are increased and are correlated with the T. forsythia load. However, the source of MGO and the extent to which MGO may contribute to periodontal inflammation has not been fully explored. In this study we identified a functional homolog of the enzyme methylglyoxal synthase (MgsA) involved in the production of MGO in T. forsythia. While wild-type T.forsythia produced a significant amount of MGO in the medium, a mutant lacking this homolog produced little to no MGO. Furthermore, compared with the spent medium of the T. forsythia parental strain, the spent medium of the T. forsythia mgsA-deletion strain induced significantly lower nuclear factor-kappa B activity as well as proinflammogenic and pro-osteoclastogenic cytokines from THP-1 monocytes. The ability of T. forsythia to induce protein glycation endproducts via MGO was confirmed by an electrophoresis-based collagen chain mobility shift assay. Together these data demonstrated that T. forsythia produces MGO, which may contribute to inflammation via the generation of AGEs and thus act as a potential virulence factor of the bacterium.