Topic
Methylglyoxal
About: Methylglyoxal is a research topic. Over the lifetime, 2844 publications have been published within this topic receiving 102037 citations. The topic is also known as: acetylformaldehyde & pyruvaldehyde.
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TL;DR: In this paper, a reversed-phase high performance liquid chromatography with a diode array detector (RP-HPLC-DAD) method was devised that involved the elimination of interfering compounds, such as chlorogenic acids, by solid phase extraction (SPE) and their derivatization with 1,2-diaminobenzene to give quinoxaline derivatives.
Abstract: Glyoxal, methylglyoxal, and diacetyl formed as Maillard reaction products in heat-treated food were determined in coffee extracts (coffee brews) obtained from green beans and beans with different degrees of roast. The compounds have been reported to be mutagenic in vitro and genotoxic in experimental animals in a number of papers. More recently, alpha-dicarbonyl compounds have been implicated in the glycation process. Our data show that small amounts of glyoxal and methylglyoxal occur naturally in green coffee beans. Their concentrations increase in the early phases of the roasting process and then decline. Conversely, diacetyl is not found in green beans and forms later in the roasting process. Therefore, light and medium roasted coffees had the highest glyoxal and methylglyoxal content, whereas dark roasted coffee contained smaller amounts of glyoxal, methylglyoxal, and diacetyl. For the determination of coffee alpha-dicarbonyl compounds, a reversed-phase high performance liquid chromatography with a diode array detector (RP-HPLC-DAD) method was devised that involved the elimination of interfering compounds, such as chlorogenic acids, by solid phase extraction (SPE) and their derivatization with 1,2-diaminobenzene to give quinoxaline derivatives. Checks of SPE and derivatization conditions to verify recovery and yield, respectively, resulted in rates of 100%. The results of the validation procedure showed that the proposed method is selective, precise, accurate, and sensitive.
81 citations
TL;DR: Results show that hippocampal neurons are strongly susceptible to MG-mediated oxidative stress, and co-treatment with the antioxidant N-acetylcysteine (NAC) completely abrogates the observed effects.
81 citations
TL;DR: It is shown that modification of human serum albumin by methylglyoxal forms mainly hydroimidazolone MG‐H1 residues, which is a high frequency of occurrence in ligand and substrate recognition sites in receptor and enzyme active sites.
Abstract: Methylglyoxal is a potent glycating agent and important precursor of advanced glycation end products (AGEs) in physiological systems. Unlike glucose, methylglyoxal is predominantly an arginine-directed glycating agent. Methylglyoxal reacts with proteins to form mainly the arginine-derived hydroimidazolone AGE, Ndelta-(5-hydro-5-methyl-4-imidazolon-2-yl)-ornithine (MG-H1), argpyrimidine, the lysine-derived AGEs, N(epsilon)-(1-carboxyethyl)lysine (CEL), and methylglyoxal-derived lysine dimer (MOLD). Sites within proteins susceptible to modification by methylglyoxal have not been identified. Here we show that modification of human serum albumin by methylglyoxal forms mainly hydroimidazolone MG-H1 residues. The location of MG-H1 residues was identified by mass spectrometric peptide mapping. This method identified a hot spot of hydroimidazolone formation at Arg-410, with other minor MG-H1 modifications at Arg-114, Arg-186, Arg-218, and Arg-428. Other extracellular and intracellular proteins are modified by methylglyoxal in physiological systems. Modification of arginine residues by methylglyoxal may be particularly damaging because arginine residues have a high frequency of occurrence in ligand and substrate recognition sites in receptor and enzyme active sites.
80 citations
TL;DR: Evidence is provided to consider ageing as a process in which lipid-radical cycles gradually substitute for lipid peroxidation, and to consider endogenous aldehydes as the major initiators of the metabolic disorders.
80 citations
TL;DR: Exogenous Spd was potent to prevent breakdown of Al-induced photosynthetic pigment and to improve growth performances under Al stress and the mechanism by which Spd enhances antioxidant and glyoxalase components might be studied extensively.
Abstract: We investigated the roles of exogenously applied Spd (0.3 mM spermidine) in alleviating Al (AlCl3, 0.5 mM, 48 and 72 h)- induced injury in mung bean seedlings (Vigna radiata L. cv. BARI Mung-2). Aluminum toxicity induced oxidative damage overproducing reactive oxygen species (ROS; H2O2 and O2•-), increasing lipoxygenase activity and membrane lipid peroxidation. The toxic compound methylglyoxal (MG) also overproduced under Al stress. In order to circumvent Al-induced oxidative stress, enzymatic and non-enzymatic antioxidant defense were activated by the application of exogenous Spd. Exogenous Spd increased ascorbate (AsA) and glutathione (GSH) content, AsA/dehydroascorbate (DHA) ratio, GSH/ glutathione disulfide (GSSG) ratio, activity of ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), glutathione reductase (GR) and catalase (CAT) which reduced ROS production and oxidative stress under Al stress. Spd-induced improvement of GSH pool and Gly II activity alleviated injurious effects of MG. Exogenous Spd positively modulated the endogenous PAs level. Regulating the osmoprotectant molecule (proline), Spd improved plant water status under Al stress. Exogenous Spd was potent to prevent breakdown of Al-induced photosynthetic pigment and to improve growth performances under Al stress. The mechanism by which Spd enhances antioxidant and glyoxalase components might be studied extensively. Spermidine-induced protection of photosynthetic pigment from damages and growth enhancement were remarkable and recommended for further detailed study to understand the mechanism.
80 citations