Browsing by Subject "Antioxidants"

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The antioxidant potential of various wheat crusts correlates with AGE content independently of acrylamide
(2023) Wächter, Kristin; Longin, Carl Friedrich H.; Winterhalter, Patrick R.; Bertsche, Ute; Szabó, Gábor; Simm, Andreas
Epidemiological studies have indicated that the consumption of whole-grain products is associated with a reduced risk of cardiovascular diseases, type II diabetes, and cancer. In the case of bread, high amounts of antioxidants and advanced glycation end products (AGEs) are formed during baking by the Maillard reaction in the bread crust; however, the formation of potentially harmful compounds such as acrylamide also occurs. This study investigated the antioxidant responses of different soluble extracts from whole-grain wheat bread crust extracts (WBCEs) in the context of the asparagine, AGE, and acrylamide content. For that, we analyzed nine bread wheat cultivars grown at three different locations in Germany (Hohenheim, Eckartsweier, and Oberer Lindenhof). We determined the asparagine content in the flour of the 27 wheat cultivars and the acrylamide content in the crust, and measured the antioxidant potential using the induced expression of the antioxidant genes GCLM and HMOX1 in HeLa cells. Our study uncovered, for the first time, that the wheat crust’s antioxidant potential correlates with the AGE content, but not with the acrylamide content. Mass spectrometric analyses of WBCEs for identifying AGE-modified proteins relevant to the antioxidant potential were unsuccessful. However, we did identify the wheat cultivars with a high antioxidant potential while forming less acrylamide, such as Glaucus and Lear. Our findings indicate that the security of BCEs with antioxidative and cardioprotective potential can be improved by choosing the right wheat variety.
Antioxidants Attenuate Heat Shock Induced Premature Senescence of Bovine Mesenchymal Stem Cells
(2022) Nir, Dana; Ribarski-Chorev, Ivana; Shimoni, Chen; Strauss, Carmit; Frank, Jan; Schlesinger, Sharon
Mesenchymal stem cells (MSC) have many roles that are important for the body’s proper functioning. When the MSC pool is damaged, it is often correlated with impaired development or health of the organism. MSC are known for their anti-inflammatory, immunomodulatory and trophic characteristics that play an important role in the physiological homeostasis of many tissues. Heat shock impairs MSC capacity by inducing the generation of reactive oxygen species and mitochondrial dysfunction, which, in turn, send the cells into a state of premature senescence. Here, we pre-exposed MSC to melatonin, resveratrol, or curcumin, which are natural antioxidative compounds, and tested the protective effects of these substances from oxidative stress and aging. Our data showed that pre-exposure of MSC to antioxidants decreased reactive oxygen species while mitochondrial damage remained high. Additionally, although the proliferation of the cells was slow, antioxidants protected the cells from premature senescence, and subsequent cytokine release was prevented. We conclude that while elevated temperatures directly cause mitochondrial damage, senescence is induced by elevated ROS levels. We suggest that heat shock alters cell and tissue homeostasis by several independent mechanisms; however, reducing tissue senescence will reduce damage and provide a pathway to overcome physiological challenges in animals.
Chemometric approach for profiling of metabolites of potential antioxidant activity in Apiaceae species based on LC-PDA-ESI-MS/MS and FT-NIR
(2023) Atta, Noha H.; Handoussa, Heba; Klaiber, Iris; Hitzmann, Bernd; Hanafi, Rasha S.
Chemometrics is a tool for data mining and unlocking the door for solving big data queries. Apiaceae is a family species which is commonly cultivated worldwide. Although members of this species are widely used as antioxidant, antibacterial, antifungal, and anti-inflammatory agents, their metabolites profiling remains ambiguous. Based on WHO support, chemometrics has been used in evaluating the quality and authenticity of the herbal products. The objective of this study is to profile and characterize phenolic metabolites in nine species from Egyptian cultivars and three different species of German cultivars from the Apiaceae family using multivariate analysis after LC-PDA-ESI-MS/MS and near infrared spectroscopy data are generated. Principal component analysis was successfully applied to distinguish between the nine Egyptian cultivars and the three German cultivars, and hierarchical cluster analysis also confirmed this distinctive clustering. Partial least square regression (PLS-R) models showed a relationship between phytochemicals and antioxidant activities. The metabolites responsible for the clustering pattern and variables important for projection (VIP) were identified, being twelve amongst nine Egyptian cultivar samples and thirteen amongst the Egyptian cultivar and the German cultivar comparison. The identified VIPs were also correlated with the antioxidant activity using PLS-R. In conclusion, the study showed novelty in the application of hyphenated analytical techniques and chemometrics that assist in quality control of herbal medicine.
Einfluss der Ernährung und von Genussmitteln auf Risikofaktoren für das Auftreten von ischämischem Herzinfarkt und Schlaganfall
(2005) Eckoldt, Joachim; Bode, Christiane
Background and aims of the study: Arteriosclerotic changes of blood vessels which contribute to coronary heart disease (CHD) and ischemic stroke are influenced by risk factors like cigarette smoking, overweight, hypertension, diabetes mellitus, missing physical exercise and nutritional factors, such as alcohol consumption. Beyond this, the concentrations of serum lipids, antioxidants, coagulation factors or other risk factors, such as C-reactive protein, and homocysteine are considered to be additional factors that indicate an enhanced or lowered risk of atherosclerosis. In this study we examined the effect of nutritional factors, in particular alcohol consumption, on various plasma components that are believed to play a role in the pathogenesis of atherosclerosis. Multiple epidemiologic studies suggest that moderate alcohol consumption reduces the mortality from cardiovascular diseases and that this effect is chiefly mediated by elevation of high-density lipoprotein (HDL). This cross-sectional study assessed the effect of moderate alcohol consumption and other life-style factors on the composition of HDL in healthy working males. An additional goal of the present study was to find out whether there is an association between alcohol consumption and the concentration of vitamins and cardio-protective substances. Methods: We included a collective of healthy men (n = 284, age 23-66 years), investigated with respect to cardiovascular risk factors. The average daily alcohol consumption, nutrient intake, smoking and other life-style factors was assessed by a computer based questionnaire. Group 1 (n = 62) comprised subjects with an average daily alcohol consumption of 0-5g, group 2 (n = 175): 5-30g, and group 3 (n = 47): 30-70g. In addition, the study design made it possible to subdivide groups 2 and 3 in a so called ?beer drinker group 2+3? (> 80 % beer), a ?wine drinker group 2+3? (> 80 % wine) and persons without preference of a certain alcoholic beverage. Results: The alcohol groups showed no significant differences in the nutritional profile (nutrients, energy intake, and metabolic rate). The markers for regular, higher alcohol consumption (g-GT and MCV) were positive correlated to the amount of alcohol consumption. There was no correlation between the great number of clinical laboratory parameters and the amount or kind of alcohol consumption. Thereby the groups are comparable in view of these laboratory parameters. Besides, there were no indications for the existence of diseases, which might influence blood lipid and vitamin concentrations. Antioxidative substances in the blood: Dietary assessment: The intake of vitamin B2, B6, B12, folic acid, retinol, ß-carotene and other carotenoids, as assessed by the computer interview was comparable in groups 1-3. The subjects in group 1 had a higher supply of the vitamins C, B1 and a-tocopherol, ?beer drinker Gr. 2+3? had a higher intake of vitamin B2, B6 and folic acid. Blood measurements: Antioxidative vitamins: The vitamin B2 status in erythrocytes (EGRAC) was lower in group 3 (vs. group 1 and 2). The plasma level of ß-carotene and ß-cryptoxanthin was lower in group 3 than in group 1. Vitamins that influence homocysteine metabolism (including homocysteine): Influence of beer and wine: The status of vitamin B6 and the concentration of free plasma pydridoxal phosphate in group 3 was significantly higher than in group 1. These results cannot explain the postulated positive influence of moderate or higher alcohol consumption through improvements of the vitamin status and the concentration of vitamins in the blood. The vitamins in beer improved the vitamin status only in case of vitamin B6, no effect was calculated in case of vitamin B2 and folic acid. Higher alcohol consumption (group 3) made the vitamin status respectively the plasma concentration of vitamin B2, ß-carotene and ß-cryptoxanthin lower compared with group 1 ? in spite of comparable supply. Coagulation factors, markers of inflammation: The coagulation factors prothrombin time and fibrinogen as well as the ?newer? risk factors C-reactive protein and homocysteine were not correlated to the amount or the kind of alcohol. Lipoproteins: The serum concentration of total cholesterol, cholesterol ester, phospholipids, apolipoprotein A-1 and A-2 was higher in group 3. Moderate and higher alcohol consumption raises the concentration of cholesterol in the high-density lipoproteins (HDL) (including subfractions) ? independent of the sort of alcoholic beverage. The concentration of cholesterol in the low- (LDL) (including subfractions), very-low (VLDL) and intermediate-density lipoproteins (IDL) in the blood was not influenced by alcohol consumption. Composition of HDL: The induced increase of HDL cholesterol was lower in the subfraction HDL3 as in the subfractions HDL2b und HDL2a. Besides we found qualitative changes of the HDL-components: the phospholipid component increased more than the other HDL-components. This phenomenon might play a beneficial role in the mechanism of atherosclerosis. Conclusions: Vitamins: The changes of antioxidative vitamins and vitamins influencing homocysteine metabolism observed in persons with moderate and increased alcohol consumption do not explain the antiatherogenic effect of alcohol. On the other hand, our study confirmed a positive association of moderate alcohol consumption with HDL plasma levels ? independent of other nutritional factors. In addition, alcohol might induce qualitative alterations of HDL composition (more pronounced increased of HDL2 relative increase of the phospholipid component). The pathophysiological significance of this phenomenon remains unclear.
An in vitro and in silico study of antioxidant properties of curcuminoid N-alkylpyridinium salts: Initial assessment of their antitumoral properties
(2022) Forero-Doria, Oscar; Guzmán, Luis; Jiménez-Aspee, Felipe; Echeverría, Javier; Wehinger, Sergio; Valenzuela, Claudio; Araya-Maturana, Ramiro; Martínez-Cifuentes, Maximiliano
In this work, we report the synthesis of curcuminoids with ionic liquid characteristics, obtained by incorporating alkyl-substituted pyridinium moiety rather than one phenyl group through a two-step process. The antioxidant capacity of the obtained compounds was evaluated in vitro by 1,1-diphenyl-picrylhydrazyl (DPPH) free radical scavenging and ferric reducing antioxidant power (FRAP) assays, showing that some derivatives are more potent than curcumin. Pyridine curcuminoids (group 4) and curcuminoid N-alkylpyridinium salts with two methoxyl groups in the phenyl ring (group 7), presented the best antioxidant capacity. The experimental results were rationalized by density functional theory (DFT) calculations of the bond dissociation enthalpy (BDE) for O–H in each compound. The computational calculations allowed for insight into the structural–antioxidant properties relationship in these series of compounds. BDEs, obtained in the gas phase and water, showed a notable impact of water solvation on the stabilization of some radicals. The lower values of BDEs in the water solution correspond to the structurally related compounds curcuminoid-pyridine 4c and curcuminoid pyridinium salt 7a, which is consistent with the experimental results. Additionally, an assessment of cell viability and cell migration assays was performed for human colon cancer (HT29), human breast cancer (MCF7) cells, in addition to NIH3T3 murine fibroblast, as a model of non-cancer cell type. These compounds mainly cause inhibition of the cell migration observed in MCF7 cancer cells without affecting the non-tumoral NIH3T3 cell line: Neither in viability nor in migration.
Micronutrients, silicon and biostimulants as cold stress protectants in maize
(2020) Moradtalab, Narges; Streck, Thilo
Mitigation of abiotic stress in crops is a feature attributed to various so-called biostimulants based on plant growth-promoting microorganisms (PGPMs) plant-, compost- and seaweed extracts, protein hydrolylates, chitosan derivatives etc. but also to mineral nutrients with protective functions, such as zinc (Zn), manganese (Mn), boron (B), calcium (Ca) and silicon (Si), recommended as stress protectants in commercial formulations. This study focussed on the effects of selected biostimulants on cold stress mitigation during early growth in maize, as a major stress factor for cultivation of tropical and subtropical crops in temperate climates. Chilling stress and micronutrient supplementation Chilling stress, induced by moderately low soil temperatures (8-14°C) in a controlled root cooling system, was associated with inhibition of shoot growth, oxidative leaf damage (chlorosis, necrosis accumulation of stress anthocyanins) and a massive decline in root length (Chapter 4 and 5). Due to inhibition of root growth, nutrient acquisition in general was impaired. However, nutrient deficiencies were recorded particularly for the micronutrients zinc (Zn) and manganese (Mn). The impaired Zn and Mn status was obviously related with the observed limitations in plant performance, which were reverted by exogenous Zn and Mn supplementation (0.5 mg plant-1), finally leading to restored nutrient acquisition and improved plant recovery after termination of the cold stress period. Zinc and manganese deficiency was mainly related with impaired uptake of the micronutrients, since the cold stress-induced deficiency symptoms persisted even in hydroponic culture when all nutrients were freely available. Beneficial effects of Zn/Mn supplementation were only detectable when the micronutrients were supplied prior to the onset of the stress period via seed soaking, seed dressing or fertigation, when uptake and internal translocation was still possible. A transcriptome analysis of the shoot tissue (Chapter 5) revealed 1400 differentially expressed transcripts (DETs) after 7-days exposure of maize seedlings to chilling stress of 12°C, mostly associated with down-regulation of selected functional categories (BINs), related with photosynthesis, synthesis of amino acids, lipids and cell wall precursors, transport of mineral nutrients (N, P, K,), metal handling and synthesis of growth hormones (auxins, gibberellic acid) but also of jasmonic (JA) and salicylic acids (SA) involved in stress adaptations. In accordance with the impaired micronutrient status and oxidative leaf damage in response to the cold stress treatments, downregulation was also recorded for transcripts related with oxidative stress defence (superoxide dismutases SOD, catalase, peroxidases POD, synthesis of phenylpropanoids and lignification), particularly dependent on the supply of micronutrients as co-factors. Upregulation was recorded for BINs related with degradation of lipids, of cell wall precursors, synthesis of waxes and certain flavonoids and of stress hormones, such as abscisic acid (ABA) and ethylene but degradation of growth-promoting cytokinins (CK). Accordingly, supplementation of Zn and Mn increased the accumulation of anthocyanins and antioxidants, the activities of superoxide dismutase and peroxidases, associated with reduced ROS accumulation (H2O2), mitigation of oxidative leaf damage and improved plant recovery at the end of the cold stress period (Chapter 5 and 6). Effects of seaweed extracts Cold-protective properties similar to Zn/Mn supplementation, associated with an improved Zn/Mn-nutritional status and reduced oxidative damage, were recorded also after fertigation with seaweed extracts prior to the onset of the stress treatments (Chapter 4). However, this effect was detectable only with seaweed extract formulations rich in Zn/Mn (Algavyt+Zn/Mn; Algafect; 6-70 mg kg DM-1) but not with a more highly purified formulation (Superfifty) without detectable micronutrient contents. This finding suggests that the cold-protective effect by soil application of seaweed extracts is based on an improved micronutrient supply and not to an elicitor effect, frequently reported in the literature for stress-protective functions after foliar application of seaweed extracts. Silicon fertilization Similar to seaweed extracts, also silicon (Si), applied by seed soaking or fertigation with silicic acid, mimicked the cold-protective effects of Zn/Mn supplementation in maize seedlings (Chapter 5). The Zn/Mn status of the Si-treated plants was improved although, in this case no additional micronutrient supply was involved. However, Si application significantly reduced leaching losses of Zn/and Mn by 50-70%, as a consequence of cold stress-induced membrane damage in germinating maize seeds and favoured the root to shoot translocation of Zn. This was associated with a restoration of gene expression, similar to the profiles recorded for unstressed control plants. However, the expression of genes related with synthesis and signal transduction of ABA, as central regulator of adaptive cold stress responses in plants, was even more strongly upregulated than in the cold-stressed controls. Accordingly, expression of cold stress adaptations involved in oxidative stress defence (SOD, peroxidases, phenolics, antioxidants) and the reduction of oxidative leaf damage and improved plant recovery were similar to the plants with Zn/Mn supplementation. Plant growth promoting microorganisms Cold-protective functions were recorded also for selected microbial inoculants (Chapter 6). However, out of five tested inoculant formulations, based on strains of Pseudomonas sp., DSMZ13134, Bacillus amyloliquefaciens FZB42, Bacillus atrophaeus ABI05, Penicillium sp. PK112 (BFOD) and a consortium of Trichoderma harzianum OMG16 and five Bacillus strains (Combi-A), a significant protective effect was detectable only for Penicillium sp. and particularly for CombiA. The CombiA consortium significantly increased root length and reduced oxidative leaf damage of cold-stressed plants, associated with increased SOD and POD activities and accumulation of phenolics and antioxidants. Root growth stimulation was related with increased IAA (indole acetic acid) tissue contents and increased expression of genes involved in IAA biosynthesis (ZmTSA) transport (ZmPIN1A) and perception (ZmAFR12). The tissue concentrations of ABA were not affected by the microbial inoculants, but the shoot concentrations of JA and SA increased, suggesting an effect by induced systemic resistance (ISR). Moreover, root concentrations of cytokinins (CKs) as ABA antagonists and expression of IPT genes involved in CK biosynthesis declined, leading to an increased ABA/cytokinin ratio and accordingly to increased expression of ABA responsive genes (ZmABF2). These findings suggest that CombiA mainly acted via improvement of root growth and nutrient acquisition by activation of the plant auxin metabolism and activation of cold protective metabolic responses by induction of ISR via JA/SA signalling and ABA-mediated responses, due to inhibition of CK biosynthesis. Synergistic interactions While the different cold-stress protectants investigated in this study induced similar protective plant responses, synergistic effects were obtained by combined applications (Chapter 6). The combination of CombiA inoculation with Zn/Mn supplementation further increased the plant micronutrient status and the cold-protective effects of CombiA. For all treatments, generally the expression of cold-protective effects was further improved by use of DMPP-stabilized ammonium fertilizers instead of nitrate fertilization. Ammonium fertilization promoted micronutrient acquisition via root-induced rhizosphere acidification, increased the ABA shoot concentrations with a moderate activation of metabolic cold stress responses and stimulated root colonization of Trichoderma harzianum OMG16 (CombiA). Field performance A comparative evaluation of the various cold protectants under field conditions with stabilized ammonium starter fertilization, revealed a severely reduced seedling emergence at six weeks after sowing (44%) due to extremely cold and wet soil conditions by the end of April in 2016, associated with a low Zn-nutritional status (32 mg kg-1 shoot DM). Significant improvements were recorded particularly for starter treatments including Zn/Mn seed dressing (emergence 56%) or seed priming with K2SiO4 (emergence 72%) and also by inoculation with the fungal PGPM strain Penicillium sp. BFOD (emergence 49%) associated with a doubling of the Zn tissue concentrations. Even after re-sowing, a significant yield increase for silo maize was recorded exclusively for the K2SiO4 treatment (Chapter 5). Taken together, the findings suggest that exploitation of synergistic interactions by combined starter applications of protective nutrients with selected biostimulants, could offer a cost-effective option for cold-stress prophylaxis in sensitive crops.