Atheroprotective potentials of curcuminoids against ginger extract in hypercholesterolaemic rabbits

The anti-atherogenic potentials of total ginger (Zingiber officinale) extract (TGE) or curcuminoids extracted from turmeric (Curcuma longa), members of family Zingiberaceae, were compared in hypercholesterolaemia. Rabbits were fed either normal or atherogenic diet. The rabbits on atherogenic diet received treatments with TGE or curcumenoids and placebo concurrently for 6 weeks (n = 6). The anti-atherogenic effects of curcuminoids and ginger are mediated via multiple mechanisms. This effect was correlated with their ability to lower cholesteryl ester transfer protein activity. Ginger extract exerted preferential effects on plasma lipids, reverse cholesterol transport, cholesterol synthesis and inflammatory status. Curcuminoids, however, showed superior antioxidant activity.     

Multistep energy and electron transfer processes in novel rotaxane donor–acceptor hybrids generating microsecond-lived charge separated states

A new set of [Cu(phen)₂]⁺ based rotaxanes, featuring [60]-fullerene as an electron acceptor and a variety of electron donating moieties, namely zinc porphyrin (ZnP), zinc phthalocyanine (ZnPc) and ferrocene (Fc), has been synthesized and fully characterized with respect to electrochemical and photophysical properties. The assembly of the rotaxanes has been achieved using a slight variation of our previously reported synthetic strategy that combines the Cu(i)-catalyzed azide–alkyne cycloaddition reaction (the “click” or CuAAC reaction) with Sauvage''s metal-template protocol. To underline our results, complementary model rotaxanes and catenanes have been prepared using the same strategy and their electrochemistry and photo-induced processes have been investigated. Insights into excited state interactions have been afforded from steady state and time resolved emission spectroscopy as well as transient absorption spectroscopy. It has been found that photo-excitation of the present rotaxanes triggers a cascade of multi-step energy and electron transfer events that ultimately leads to remarkably long-lived charge separated states featuring one-electron reduced C₆₀ radical anion (C₆₀˙^–) and either one-electron oxidized porphyrin (ZnP˙⁺) or one-electron oxidized ferrocene (Fc˙⁺) with lifetimes up to 61 microseconds. In addition, shorter-lived charge separated states involving one-electron oxidized copper complexes ([Cu(phen)₂]²⁺ (τ < 100 ns)), one-electron oxidized zinc phthalocyanine (ZnPc˙⁺; τ = 380–560 ns), or ZnP˙⁺ (τ = 2.3–8.4 μs), and C₆₀˙^– have been identified as intermediates during the sequence. Detailed energy diagrams illustrate the sequence and rate constants of the photophysical events occurring with the mechanically-linked chromophores. This work pioneers the exploration of mechanically-linked systems as platforms to position three distinct chromophores, which are able to absorb light over a very wide range of the visible region, triggering a cascade of short-range energy and electron transfer processes to afford long-lived charge separated states.     

Vibration Spectroscopy Stability Investigation of 12-Tungstosilicic Acid Solution

Heteropoly acids (HPA) attract the attention of large variety of scientists, due to HPA’s extraordinary interesting properties and possible application fields. 12-tungstosilicic acid (WSiA), the Keggin type HPA, has some promising characteristic to be used in catalytic processes, but with not well-defined stability. Raman spectroscopy was used for in situ analysis of WSiA hydrolysis in detail in a wide pH range of 1–12. Raman spectroscopy is able to give an almost immediate response/spectrum as a representation of the exact profile/composition of the solution. This method and FTIR spectroscopy, as a complementary technique, enabled recording of the solid and liquid phases of the same sample under different conditions. Our results confirm that the decomposition pathways of WSiA in solution proceed via the formation of the lacunary monovacant anion at pH > 6.4. This anion is a major constituent in pH range up to 9.5. With further increases in pH this species convert to the trivacant lacunary anion. The total decomposition of the Keggin anion to silicate and tungstate occurs at pH > 11.0. The results of the performed study contribute to understand the behavior of WSiA in the water–methanol solution, as the model system of aqueous-organic system. It is concluded that addition of methanol in aqueous solution of WSiA leads to expansion of the pH region where Keggin anion is stable up to 8.1 and above this pH value, precipitation occurs. The obtained data clarify the stability range of WSiA in both water and water–methanol solutions, as well.     

Selective adsorption of metronidazole on conjugated microporous polymers

Conjugated microporous polymers (CMPs) have recently received extensive attention in oil/organic solvent-water separation field as a kind of ideal porous absorbents with tunable porosity, large surface areas, and super-hydrophobicity. However, reports on the application of CMPs in adsorption of hydrophilic contaminants from water are very few. In this work, we studied the adsorption of metronidazole (MNZ), a polar antibiotic, by two kinds of CMPs. The adsorption characteristics of MNZ by the CMPs, including adsorption kinetics, mechanism, and isotherm parameters were calculated. The adsorption kinetics of MNZ was well expressed by the pseudo-second-order model, and the adsorption process was found to be mainly controlled by film diffusion. The adsorption isotherm data agreed well with the Langmuir isotherm model, and the values of free energy E indicated that the adsorption nature of MNZ on the CMPs was physisorption. Increasing dispersion degree of the CMPs in MNZ solution resulted in greater adsorption. This work may provide fundamental guidance for the removal of antibiotics by CMPs.