1,721,001 research outputs found
Chain-breaking antioxidant activity of hydroxylated and methoxylated magnolol derivatives: The role of H-bonds
No full textChemical modification of magnolol, an uncommon dimeric neolignan contained in Magnolia genus trees, provides a unique array of polyphenols having interesting biological activity potentially related to radical scavenging. The chain-breaking antioxidant activity of four new hydroxylated and methoxylated magnolol derivatives was explored by experimental and computational methods. The measurement of the rate constant of the reaction with ROO center dot radicals (k(inh)) in an apolar solvent showed that the introduction of hydroxyl groups ortho to the phenolic OH in magnolol increased the k(inh) value, being 2.4 x 10(5) M-1 s(-1) and 3.3 x 10(5) M-1 s(-1) for the mono and the dihydroxy derivatives respectively (k(inh) of magnolol is 6.1 x 10(4) M-1 s(-1)). The di-methoxylated derivative is less reactive than magnolol (k(inh) = 1.1 x 10(4) M-1 s(-1)), while the insertion of both hydroxyl and methoxyl groups showed no effect (6.0 x 10(4) M-1 s(-1)). Infrared spectroscopy and theoretical calculations allowed a rationalization of these results and pointed out the crucial role of intramolecular H-bonds. We also show that a correct estimation of the rate constant of the reaction with ROO center dot radicals, by using BDE(OH) calculations, requires that the geometry of the radical is as close as possible to that of the parent phenol
A heterotetrameric alpha-amylase inhibitor from emmer (Triticum dicoccon Schrank) seeds
No full textPlants have developed a constitutive defence system against pest attacks, which involves the
expression of a set of inhibitors acting on heterologous amylases of different origins.
Investigating the soluble protein complement of the hulled wheat emmer we have isolated and
characterized a heterotetrameric α-amylase inhibitor (ETI). Based on mass spectroscopy data, it is
an assembly of proteins highly similar to the CM2/CM3/CM16 found in durum wheat. Our data
indicate that these proteins can also inhibit exogenous α-amylases in binary assemblies. The
calculated dissociation constants (Ki) for the pancreatic porcine amylase- and human salivary
amylase-ETI complexes are similar to those found in durum and soft wheat. Homology modeling of
the CM subunits indicate structural similarities with other proteins belonging to the cereal family of
trypsin/α-amylase inhibitors; a possible homology modeled structure for a tetrameric assembly of
the subunits is proposed
Dimeric inhibitors of human salivary alpha-amylase from emmer (Triticum dicoccon Schrank) seeds
No full textSynthesis of Rosmarinic Acid Amides as Antioxidative and Hypoglycemic Agents
No full textType 2 diabetes mellitus (T2DM) is an important metabolic disorder for which there is an urgent need for new antidiabetic drugs. α-Glucosidase inhibition is an established protocol for T2DM therapy. Because hyperglycemia causes oxidative tissue damage, the development of agents with both α-glucosidase inhibition and antioxidant activity from natural or natural-derived polyphenols such derivatives of rosmarinic acid (RA) represents an attractive therapeutic option. We report a study on amides 1-10 derived from RA and their evaluation for yeast α-glucosidase inhibition and antioxidant activity (DPPH and ORAC tests). All amides showed higher inhibitory activity than that of RA, were by far more potent than the antidiabetic drug acarbose, and proved to be effective antioxidants. A molecular docking study displayed significant binding interactions of RA amides with the active site of α-glucosidase. This in silico optimization study led to the design and synthesis of amides 9 (IC 50 = 42.3 μM) and 10 (IC 50 = 35.2 μM), showing the most potent α-glucosidase inhibition and good antioxidative properties. A kinetic study showed that 10 acts as a mixed type inhibitor
Nanosponges based on self-assembled starfish-shaped cucurbit[6]urils functionalized with imidazolium arms
No full textA new porous material based on the first supramolecular cucurbituril-based nanosponge was synthesized by the functionalization of cucurbit[6]uril with twelve 1-(2-bromoethyl)-3-methyl-1H-imidazol-3-ium arms. The porous structure and the high adsorption capacity were demonstrated through surface area measurements and carbon dioxide adsorption. The new supramolecular sponge showed attractive properties such as (i) a highly porous structure that allowed CO2capture, (ii) the possibility to reuse the adsorbed CO2for organic synthesis, and (iii) an exciting thermal stability up to around 800 °C, with the potential use of this material in high temperature reactions. Finally, the reuse of CO2was successfully investigated in the carboxylation reaction of phenylacetylene
A polyphenol-rich extract from an oenological oak-derived tannin influences in vitro maturation of porcine oocytes
Full text linkTannins have been demonstrated to have antioxidant and various health benefit properties. The aim of this study was to determine the effect of an ethanol extract (TRE) of a commercial oenological tannin (Quercus robur toasted oak wood, Tan'Activ R ® ) on female gamete using an in vitro model of pig oocyte maturation (IVM) and examining nuclear maturation, cytoplasmic maturation, intracellular GSH and ROS levels and cumulus cell steroidogenesis. To this aim, during IVM performed in medium either supplemented (IVM A) or not supplemented (IVM B) with cysteine and β-mercaptoethanol, TRE was added at different concentrations (0, 1, 5, 10, 20 μg/ml). The addition of TRE at all the concentration tested to either IVM A or IVM B, did not influence oocyte nuclear maturation. When IVM was performed in IVM A, no effect was induced on cytoplasmic maturation by TRE at the concentration of 1, 5 and 10 μg/ml, while TRE 20 μg/ml significantly reduced the penetration rate after IVF (p < 0.05) and the blastocyst rate after parthenogenetic activation (p < 0.01). Oocyte maturation in IVM B, compared to IVM A group, decreased GSH (p < 0.001) and increased ROS (p < 0.01) intracellular levels and in turn impaired oocyte cytoplasmic maturation reducing the ability to sustain male pronuclear formation after IVM (p < 0.001) and the developmental competence after parthenogenetic activation (p < 0.001). TRE supplementation to IVM B significantly reduced ROS production (5, 10, 20 μg/ml TRE) to levels similar to IVM A group, and increased GSH levels (10, 20 μg/ml TRE) compared to IVM B (p < 0.05) without reaching those of IVM A group. TRE supplementation to IVM B at the concentrations of 1, 5 and 10 μg/ml significantly improved (p < 0.001) oocyte cytoplasmic maturation enhancing the ability to sustain male pronuclear formation without reaching, however, IVM A group levels. TRE addition at all the concentration tested to both IVM A and IVM B, did not induce any effect on E2 and P4 secretion by cumulus cells suggesting that the biological effect of the ethanol extract is not exerted thought a modulation of cumulus cell steroidogenesis. In conclusion, TRE, thanks to its antioxidant activity, was partially able to reduce the negative effect of the absence of cysteine and β-mercaptoethanol in IVM B, while TRE at high concentration in IVM A was detrimental for oocyte cytoplasmic maturation underlying the importance of maintaining a balanced redox environment during oocyte maturation
Proteomic analysis of proteins responsive to drought and low temperature stress in a hard red spring wheat cultivar
Full text linkDrought stress is becoming more prevalent with global warming, and has been shown to have large effects on gluten proteins linked to wheat bread making quality. Likewise, low temperature stress can detrimentally affect proteins in wheat. This study was done to determine the differential abundance of high molecular weight (HMW) glutenin proteins in a drought and low temperature stressed high quality hard red spring wheat cultivar (PAN3478), against a control. The treatments were applied in the greenhouse at the soft dough stage. HMW glutenin proteins were extracted from the flour, and were separated by using two-dimensional gel electrophoresis. Protein spots that had p values lower than 0.05 and fold values equal to or greater than 1.2 were considered to be significantly differentially abundant. These proteins were further analyzed by using tandem mass spectrometry. There was a 1.3 to 1.8 fold change in 17 protein spots due to the cold treatment. The drought treatment caused a 1.3 to 3.8 fold change in 19 protein spots. These spots matched either HMW or low molecular weight (LMW) glutenin subunits. In the latter case, the C subunits of LMW glutenins were notably found to be up-regulated under both stress conditions. All the proteins that have been identified can directly influence dough characteristics. Data are available via ProteomeXchange with the identifier PXD017578
A preliminary investigation of the emmer (Triticum dicoccon Schrank) seed soluble proteome
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