Effect of Quercetin on Paraoxonase 2 Levels in RAW264.7 Macrophages and in Human Monocytes––Role of Quercetin Metabolism

There is increasing evidence that the intracellular antioxidant enzyme paraoxonase 2 (PON2) may have a protective function in the prevention of atherogenesis. An enhancement of PON2 activity by dietary factors including flavonoids is therefore of interest. In the present study we determined the effect of quercetin on paraoxonase 2 levels in cultured murine macrophages in vitro and in overweight subjects with a high cardiovascular risk phenotype supplemented with 150 mg quercetin/day for 42 days in vivo. Supplementation of murine RAW264.7 macrophages in culture with increasing concentrations of quercetin (1, 10, 20 μmol/L) resulted in a significant increase in PON2 mRNA and protein levels, as compared to untreated controls. Unlike quercetin, its glucuronidated metabolite quercetin-3-glucuronide did not affect PON2 gene expression in cultured macrophages. However the methylated quercetin derivative isorhamnetin enhanced PON2 gene expression in RAW264.7 cells to similar extent like quercetin. Although supplementing human volunteers with quercetin was accompanied by a significant increase in plasma quercetin concentration, dietary quercetin supplementation did not change PON2 mRNA levels in human monocytes in vivo. Current data indicate that quercetin supplementation increases PON2 levels in cultured monocytes in vitro but not in human volunteers in vivo

Psychosocial Stress Increases Salivary Alpha-Amylase Activity Independently from Plasma Noradrenaline Levels.

Salivary alpha-amylase activity (sAA) and plasma noradrenaline (NA) concentrations are often considered to be surrogate markers of sympathetic activation in response to stress. However, despite accumulating evidence for a close association between sAA and noradrenaline and other indicators of sympathetic activity, reliability and generality of this relation remains unclear. We employed the Trier Social Stress Test (TSST) in order to directly compare the responses in sAA and NA to psychological stress in healthy volunteers (n = 23). The TSST significantly increased sAA and NA plasma levels with no significant differences in females and males. However, when subjects were divided according to their NA responses into low versus high responders, both groups did not significantly differ in their sAA before, during or after stress exposure. These data suggest that in response to acute psychological stress both plasma NA levels and sAA reflect sympathetic activity, however seemed to increase independently from each other

Ruthenium(II) and osmium(II) polypyridyl complexes of an asymmetric pyrazinyl- and pyridinyl-containing 1,2,4-triazole based ligand. Connectivity and physical properties of mononuclear complexes

The synthesis, purification and characterisation of two coordination isomers of ruthenium(II) and osmium (II) complexes containing the ligand 3-(pyrazin-2'-yl)-5-(pyridin-2"-yl)-1,2,4-triazole (Hppt) are described. The X-ray and molecular structure of the complex [Ru(bipy)2(ppt)]PF6·CH3OH is reported, where the Ru(bipy)2-centre is bound to the ppt- ligand via the pyridine nitrogen and the N1 atom of the triazole ring. 1H NMR spectroscopic measurements confirm that in the second isomer the Ru(bipy)2-moiety is bound via the N2 atom of the triazole ring and the pyrazine ring. Partially deuteriated metal complexes are utilised to facilitate interpretation of 1H NMR spectra. The redox and electronic properties indicate that there are significant differences in the electronic properties of the two coordination isomers obtained. The acid–base properties of the compounds are also reported and show that the pKa of the 1,2,4-triazole ring varies systematically depending on the nature of the non-coordinating substituent. Analysis of these data indicates a significant electronic interaction between the pyridyl/pyrazyl rings and the 1,2,4-triazole ring in the coordinated ppt- ligand.

Assessment of intercomponent interaction in phenylene bridged dinuclear ruthenium(II) and osmium(II) polypyridyl complexes

The synthesis and characterisation of [Ru(bipy)2(L1)]2+ and the homodinuclear complexes [M(bipy)2(L1)M(bipy)2]4+ (where M = Ru or Os), employing the ditopic ligand, 1,4-phenylene-bis(1-pyridin-2-ylimidazo[1,5-a]pyridine) (L1), are reported. The complexes are identified by elemental analysis, UV/Vis, emission, resonance Raman, transient resonance Raman and 1H NMR spectroscopy, mass spectrometry and electrochemistry. The X-ray structure of the complex [Ru(bipy)2(L1)(bipy)2Ru](PF6)4 is also reported. DFT calculations, carried out to model the electronic properties of the compounds, are in good agreement with experiment. Minimal communication between the metal centres is observed. The low level of ground state electronic interaction is rationalized in terms of the poor ability of the phenyl spacer in facilitating superexchange interactions. Using the electronic and electrochemical data a detailed picture of the electronic properties of the RuRu compound is presented.

Benign and High-Yielding, Large-Scale Synthesis of Diphenylphosphinodithioic Acid and Related Compounds

Diphenylphosphinodithioic acid (<b>6b</b>) and its triethyl ammonium salt (<b>6a</b>) were prepared by two new synthetic pathways, each employing cheap and readily available starting materials. These facile one-pot reactions were conducted on a kilogram scale and produced the desired products in high yield and quality, thereby surpassing all previously known routes. The synthesis of triethyl ammonium salts of 6<i>H</i>-dibenzo­[<i>c</i>,<i>e</i>]­[1,2]­oxaphosphinine-6-thiolate 6-sulfide (<b>3a</b>) was also further improved

The distribution of Noradrenaline response to the Trier Social Stress Test among individuals.

<p>The distribution of Noradrenaline response to the Trier Social Stress Test among individuals.</p

Noradrenaline (A), Salivary alpha-amylase (B), Plasma cortisol (C), Salivary cortisol (D), Nervousness (E), State anxiety (F) and Heart rate (G) in response to the Trier Social Stress Test for 2 groups with high-NA and low-NA response.

<p>Results are presented as mean ± SEM.</p

(A) Experimental design. (B) Noradrenaline and (C) salivary alpha-amylase response to the Trier Social Stress Test.

<p>Results are presented as mean ± SEM.</p