ARTICLE | doi:10.20944/preprints202009.0383.v1
Subject: Life Sciences, Molecular Biology Keywords: Methylglyoxal; Glyoxalase system; AGEs; glutathione; hyperglycemia
Online: 17 September 2020 (07:45:11 CEST)
Chronic high glucose (HG) exposure increases methylglyoxal (MG)-derived AGEs and is involved in the onset of pathological conditions, such as diabetes, atherosclerosis and chronic‐degenerative diseases. Under physiologic condition the harmful effects of MG are contrasted by glyoxalase system that is involved in the detoxification of Reactive Carbonyl Species (RCS) and maintain the homeostasis of the redox environment of the cell. Polyphenols are the most abundant antioxidants in the diet and present various health benefits. The study aimed at investigating the role of polyphenols extracted from an apple high in polyphenols (Calville White Winter), on glyco-oxidative stress induced by chronic HG-exposure. Intestinal Caco-2 cells were treated in physiological glucose condition (25mM) as a control and in HG condition (50mM) with or without apple extract for one week. Our data demonstrated that HG-treatment triggers glyco-oxidation stress with a significantly increase in ROS, lipid peroxidation, AGEs and Glyoxalase I (GlxI) activity with a significant decrease in total antioxidant intracellular defense. Treatment with polyphenols under HG condition restores to the control levels GlxI activity, decreases Glyoxalase II (GlxII) in relation to the control and induces a drop of glyco-oxidative damage. This paper seeks to highlight the roles of polyphenols in glyco-oxidative stress.
ARTICLE | doi:10.20944/preprints201911.0358.v1
Subject: Biology, Plant Sciences Keywords: abiotic stress; oxidative stress; salinity; nutrient deficiency; osmolytes; methylglyoxal
Online: 28 November 2019 (09:49:35 CET)
This study was undertaken to elucidate the role of trehalose (Tre) in mitigating oxidative stress under salinity and low P in maize. Eight-day-old maize seedlings of two maize varieties, BARI Hybrid Maize-7 and BARI Hybrid Maize-9 were subjected to salinity (150 mM NaCl), low P (5 µM KH2PO4) and their combined stress with or without 10 mM Tre for 15-d.Salinity and combined stress significantly inhibited the shoot length, root length, and root volume, whereas, low P increased the root length and volume in both genotypes. Exogenous Tre in the stress treatments increased all of the growth parameters as well as decreased the salinity, low P and combined stress-mediated Na+/K+, ROS, MDA, LOX activity and MG in both genotypes. Under salinity and low P stress, the SOD activity increased in both genotypes, but the activity decreased in combined stress. POD activity increased in all stress treatments. Interestingly, Tre application enhanced the SOD activity in all the stress treatments but inhibited the POD activity. Both CAT and GPX activity were increased by saline and low P stress while the activities inhibited in combined stress. Similar results were found for APX, GR, and DHAR activities in both genotypes. However, MDHAR activity was inhibited in all the stresses. Interestingly, Tre enhanced CAT APX, GPX, GR, MDHAR and DHAR activities suggesting the amelioration of ROS scavenging in maize under all the stresses. Increased GST activity in presence or absence of Tre might involve in detoxification of hydroperoxides as well as leaf senescence. On the other hand, increased glyoxalase activities in saline and low P stress in BHM-9 suggested better MG detoxification system because of down-regulation of Gly-I activity in BHM-7 in those stresses. Tre also increased the glyoxalase activities in both genotypes under all the stresses. Tre improved the growth in maize seedlings by decreasing Na+/K+, ROS, MDA, and MG through regulating antioxidant and glyoxalase systems.
ARTICLE | doi:10.20944/preprints201901.0143.v1
Subject: Biology, Agricultural Sciences & Agronomy Keywords: acidity; alkalinity; antioxidant defense; methylglyoxal; phytotoxicity; reactive oxygen species
Online: 15 January 2019 (07:37:11 CET)
Soil pH, either low (acidity) or high (alkalinity) is one of the major constraints that affect many biochemical and biological processes within the cell. The present study was carried out to understand the oxidative damage and antioxidant defense in wheat (Triticum aestivum L. cv. BARI Gom-25) grown under different pH regimes. Eight-day-old seedlings were exposed to growing media with different pH levels (4.0, 5.5, 7.0 and 8.5). Seedlings grown in pH 4.0 and in pH 8.5 showed reductions in biomass, water, and chlorophyll contents; whereas plants grown at pH 7.0 (neutral) exhibited better performance. Extremely acidic (pH 4.0) and/or strongly alkaline (pH 8.5)-stress also increased oxidative damages in wheat by excess reactive oxygen species (ROS) generation and methylglyoxal (MG) production, which increased lipid peroxidation and disrupted the redox state. In contrary, the lowest oxidative damage was observed at neutral condition followed by strong acidic condition (pH 5.5), which was attributed mainly due to better performance of the antioxidant defense and glyoxalase systems. Interestingly, seedlings grown at pH 5.5 showed a significant increase in morphophysiological attributes compared with extreme acidic (pH 4.0)- and strong alkaline (pH 8.5)-stress treatments, which indicates the tolerance of wheat to the acidic condition.
Subject: Life Sciences, Microbiology Keywords: honey; antimicrobials; methylglyoxal; hydrogen peroxide; bee-defensin 1; wound treatment
Online: 29 October 2019 (10:45:51 CET)
Honey is a complex sweet food stuff with well-established antimicrobial and antioxidant properties. It has been used for millennia in a variety of applications, but those most noteworthy include treatment of surface wounds, burns and inflammation. A variety of substances in honey have been suggested as the key component to its antimicrobial potential; polyphenolic compounds, hydrogen peroxide, methylglyoxal and bee-defensin 1. These components vary greatly across honey samples due to botanical origin, geographical location and the individual bee. The use of medical grade honey, Medihoney and Revamil, in the treatment of surface wounds and burns has been seen to improve the healing process, reduce healing time, reduce scarring and prevent microbial contamination. Therefore, medical grade honeys should be used for these treatments and reduce the demand for antibiotic usage. In this review, we aim to outline the constituents of honey and how they affect the antibiotic potential of honeys in a clinical setting.
ARTICLE | doi:10.20944/preprints201812.0126.v1
Subject: Chemistry, Analytical Chemistry Keywords: advanced glycation end products (AGEs); enzymatic hydrolysis; glycation; methylglyoxal-derived hydroimidazolone 1 (MG-H1); seeds; seed ageing; seed quality; sodium dodecyl sulfate (SDS)
Online: 11 December 2018 (10:40:15 CET)
Seeds represent the major source of food protein, impacting on both human nutrition and animal feeding. Therefore, seed quality needs to be appropriately addressed in the context of viability and food safety. Indeed, long-term and inappropriate storage of seeds might result in enhancement of protein glycation, which might affect their quality and longevity. Glycation of seed proteins can be probed by exhaustive acid hydrolysis and quantification of the glycation adduct Nɛ-(carboxymethyl)lysine (CML) by liquid chromatography-mass spectrometry (LC-MS). This approach, however, does not allow analysis of thermally and chemically labile glycation adducts, like glyoxal-, methylglyoxal- and 3-deoxyglucosone-derived hydroimidazolones. Although enzymatic hydrolysis might be a good solution in this context, it requires aqueous conditions, which cannot ensure reconstitution of seed protein isolates. Because of this, the complete profiles of seed AGEs are not characterized so far. Therefore, here we propose the approach, giving access to quantitative solubilization of seed proteins in presence of sodium dodecyl sulfate (SDS) and their quantitative enzymatic hydrolysis prior to removal of SDS by reversed phase solid phase extraction (RP-SPE). Using MG-H1 as a case example, we demonstrate the applicability of this method for reliable and sensitive LC-MS-based quantification of chemically labile AGEs and its compatibility with bioassays.