Insights into the Structure-Capacity of Food Antioxidant Compounds Assessed Using Coulometry.

CDAC (coulometrically determined antioxidant capacity) involves the determination of the antioxidant capacity of individual compounds or their mixtures using constant-current coulometry, with electrogenerated Br as the titrant, and biamperometric detection of the endpoint via Br excess. CDAC is an accurate, sensitive, rapid, and cheap measurement of the mol electrons (mol e) transferred in a redox process. In this study, the CDAC of 48 individual antioxidants commonly found in foods has been determined.

Evaluation of Novel Rapid Analytical Methods to Categorize Extra Virgin Olive Oil Based on the Coulometrically Determined Antioxidant Capacity and on the Spectrophotometric Assessment of Phenolic Compounds.

The lack of a practical "fit for the purpose" analytical protocol is the main limitation that has hampered the exploitation of the EFSA analytical health claim on the extra virgin olive oil (EVOO) biophenols, more than ten years since its introduction. In this work, two analytical methods recently developed in our laboratories for categorizing EVOO have been evaluated on a set of 16 samples from Cilento (Campania Region, southern Italy) and compared to other commonly used quality indexes. The Coulometrically Determined Antioxidant Capacity (CDAC) is associated with the component responsible for the health-promoting properties and oxidative stability of EVOO.

Fluorescence Detecting of Paraquat and Diquat Using Host-Guest Chemistry with a Fluorophore-Pendant Calix[6]arene.

Paraquat (PQ) and diquat (DQ), some of the most widely used herbicides in the world, both present a high mortality index after intentional exposure. In this paper, a fluorescence sensing method for PQ and DQ, based on host-guest molecular recognition, is proposed. Calix[6]arene derivatives containing anthracene or naphthalene as pendant fluorophore at their lower rim recognize DQ and PQ in hydroalcoholic solution with a broad linear response range at the μg L level concentration.

Electrochemical-Induced Cascade Reaction of 2-Formyl Benzonitrile with Anilines: Synthesis of -Aryl Isoindolinones.

An electrochemical initiated tandem reaction of anilines with 2-formyl benzonitrile has been developed. Thus, unprecedented 3--aryl substituted isoindolinones have been conveniently achieved by constant current electrolysis in a divided cell using catalytic amount of electricity and supporting electrolyte and a Pt-cathode as working electrode. The origin of the electrochemical activation as well as the mechanism of the subsequent chemical cascade reactions have been investigated by DFT calculations.

Monitoring antioxidants by coulometry: Quantitative assessment of the strikingly high antioxidant capacity of bergamot (Citrus bergamia R.) by-products.

A recently optimized rapid, cheap, and accurate coulometric method has been exploited to determine the antioxidant capacity of bergamot (Citrus bergamia Risso) by-products, including first (FPJ) and second press juices (SPJ), in comparison to analogous products from several citrus species. Extracts from the entire edible part (i.e.

Proteomics and Integrated Techniques to Characterize Organic Residues in Funerary Findings from Italic Populations of the First Millennium BC.

Multiple analytical techniques were combined to achieve a detailed characterization of organic residues in different typologies of funerary pottery, which were found at two separate archeological sites in the Campania Region (Italy) and both dated back to the first millennium BC. Gas chromatography-mass spectrometry (GC-MS) analysis of lipids provided inconclusive results. The attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectra of encrustation on two glazed bowls of the 3rd to 4th century BC were comparable to those of fresh bone, revealing the presence of hydroxyapatite and proteins, which were identified as bovine collagen chains by liquid chromatography coupled to high-resolution tandem mass spectrometry (LC-MS/MS)-based proteomics.

The Dynamics of Hole Transfer in DNA.

High-energy radiation and oxidizing agents can ionize DNA. One electron oxidation gives rise to a radical cation whose charge (hole) can migrate through DNA covering several hundreds of Å, eventually leading to irreversible oxidative damage and consequent disease. Understanding the thermodynamic, kinetic and chemical aspects of the hole transport in DNA is important not only for its biological consequences, but also for assessing the properties of DNA in redox sensing or labeling.

High Biodiversity Arises from the Analyses of Morphometric, Biochemical and Genetic Data in Ancient Olive Trees of South of Italy.

Morphometric, biochemical and genetic analyses were conducted on L. of Campania, an area of Southern Italy highly suited to the cultivation of olive trees and the production of extra virgin olive oil (EVOO). We aimed to characterize the distribution of morphological, biochemical and genetic diversity in this area and to develop a practical tool to aid traceability of oils.

The Effect of Bulky Substituents on Two π-Conjugated Mesogenic Fluorophores. Their Organic Polymers and Zinc-Bridged Luminescent Networks.

From a dicyano-phenylenevinylene (PV) and an azobenzene (AB) skeleton, two new symmetrical salen dyes were obtained. Terminal bulky substituents able to reduce intermolecular interactions and flexible tails to guarantee solubility were added to the fluorogenic cores. Photochemical performances were investigated on the small molecules in solution, as neat crystals and as dopants in polymeric matrixes.

Stable ruthenium olefin metathesis catalysts bearing symmetrical NHC ligands with primary and secondary N-alkyl groups.

Four novel stable Hoveyda-Grubbs-type catalysts containing N,N'-dineopentyl- and N,N'-dicyclohexyl-substituted N-heterocyclic carbene (NHC) ligands with syn and anti phenyl groups on the ring backbone were synthesized and fully characterized. The catalytic potential of these complexes was investigated in metathesis reactions of both standard and renewable substrates. Compared to the Hoveyda-Grubbs second generation catalyst (HGII), all of the new catalysts showed high performances in most of the examined metathesis transformations.

Silibinin phosphodiester glyco-conjugates: Synthesis, redox behaviour and biological investigations.

New silibinin phosphodiester glyco-conjugates were synthesized by efficient phosphoramidite chemistry and were fully characterized by 2D-NMR. A wide-ranging study focused on the determination of their pKa and E° values as well as on their radical scavenging activities by different assays (DPPH, ABTS and HRSA) was conducted. The new glyco-conjugates are more water-soluble than silibinin, and their radical scavenging activities are higher than those of silibinin.

An Anthracene-Incorporated [8]Cycloparaphenylene Derivative as an Emitter in Photon Upconversion.

The anthracene-incorporated [8]cycloparaphenylene 2 has been synthesized and its optoelectronic properties studied by UV-vis spectroscopy, cyclic voltammetry, and DFT calculations. NMR and computational studies indicate that the new cycloparaphenylene derivative possesses a C point group symmetry. The new CPP 2 exhibits peculiar optoelectronic properties: (i) fluorescence emission is blue-shifted with respect to [8]cycloparaphenylene 1, and its quantum yield is higher; (ii) in the presence of an octaethylporphyrin Pd complex, as sensitizer, it undergoes a visible light upconversion.

Tuning Cycloparaphenylene Host Properties by Chemical Modification.

[8]Cycloparaphenylene derivative 1 has been synthesized and its recognition abilities toward pyridinium guests have been investigated and compared with the [8]CPP macrocycle. The results showed a fine-tuning of the binding properties of [8]CPP 1 toward pyridinium cations due to the presence of the 1,4-DMB ring. DFT calculations indicate that the close steric fitting between the rigid cavity of 1 and the pyridinium guest is the crucial factor for the stabilization of their supramolecular complex through C-H···π and N···π interactions.

The association constant of 5',8-cyclo-2'-deoxyguanosine with cytidine.

The association of 5',8-cyclo-2'-deoxyguanosine (cdG), a DNA tandem lesion, with its complementary base cytosine has been studied by voltammetry and NMR in chloroform, using properly silylated derivatives of the two nucleobases for increasing their solubilities. Both voltammetric data and NMR titrations indicated that the Watson-Crick complex of cytidine with cdG is weaker than that with guanosine, the difference being approximately of one order of magnitude between the two association constants.

Delocalized hole domains in Guanine-rich DNA oligonucleotides.

Differential pulse voltammetries of guanine-rich single- and double-stranded oligonucleotides containing up to six consecutive guanines are reported. The observed progressive lowering of the first voltammetric peak potential as the number of adjacent guanines increases unambiguously points toward the establishment of delocalized hole domains; the hole stabilization energy is ca. 0.

Hole delocalization over adenine tracts in single stranded DNA oligonucleotides.

Adiabatic ionization energies of single stranded DNA oligonucleotides containing adenine tracts of different sizes have been computed at the DFT level and compared with the oxidation potentials determined by differential pulse voltammetry. Geometry optimizations have been performed at the full quantum mechanical level, including the sugar phosphate backbone and solvent effects. The observed progressive lowering of the ionization energy upon increasing the number of consecutive adenines is well predicted, the computed ionization potential shifts being in very good agreement with the experimental outcomes, both by using pure and hybrid functionals.

Light modulation of biomass and macromolecular composition of the diatom Skeletonema marinoi.

The biochemical profile and growth of the coastal diatom Skeletonema marinoi was investigated under four different daily blue light doses (sinusoidal light peaking at 88, 130, 250 and 450 μmol photons m(−2) s(−1), respectively). Ability of cells to regulate the light energy input caused alterations in growth and different biosynthetic pathways. The light saturation index for photosynthesis (E(k)), which governs the photoacclimative processes, ranged between 250 and 300 μmol photons m(−2) s(−1).

Proton transfer in oxidized adenosine self-aggregates.

The UV-vis and the IR spectra of derivativized adenosine in dichloromethane have been recorded during potentiostatic oxidation at an optically transparent thin layer electrode. Oxidized adenosine shows a broad Zundel like absorption extending from 2800 up to 3600 cm(-1), indicating that a proton transfer process is occurring. Theoretical computations predict that proton transfer is indeed favored in oxidized 1:1 self-association complexes and allow to assign all the observed transient spectroscopic signals.

Stacking interactions between adenines in oxidized oligonucleotides.

The effects of stacking interactions on the oxidation potentials of single strand oligonucleotides containing up to four consecutive adenines, alternated with thymines and cytosines in different sequences and ratios, have been determined by means of differential pulse voltammetry. Voltammetric measurements point toward the establishment in solution of structured oligonucleotide conformations, in which the nucleobases are well stacked altogether. Molecular dynamics simulations confirm that finding, indicating that single strands assume geometrical parameters characteristic of the B-DNA form.

Characterization of high purity lycopene from tomato wastes using a new pressurized extraction approach.

In this paper, a method for the extraction of high purity lycopene from tomato wastes is presented. The method is based on a pressurized extraction that uses the Extractor Naviglio, and it is performed in the 0.7-0.

The oxidation potential of adenosine and adenosine-thymidine base pair in chloroform solution.

The oxidation potential of 2',3'-O-isopropylidene-5'-O-(tert-butyldimethylsilyl)adenosine and its change upon pairing with the complementary base thymidine have been studied in chloroform solution by voltammetric methods. Differential pulse and cyclic voltammetry of an equimolar solution of the two nucleosides show two well-resolved peaks, which have been assigned to the formation of a H-bonded complex between the two nucleosides and to the fraction of unassociated adenosine in solution. No signal for thymidine oxidation has been detected.

On the hydrolysis of the dioxouranium(VI) ion in oxalate solutions.

The complex formation between the dioxouranium (VI) and the oxalate ions has been investigated by measuring the potential of a glass electrode, at 25.00 degrees C, in 1 and 3 M NaClO4, at lower acidities than 10(-4.5) M, in order to favour the formation of (mixed) ternary species.

Direct experimental observation of the effect of the base pairing on the oxidation potential of Guanine.

The effect of complementary base pairing on the oxidation potential of a guanosine derivative has been determined by cyclic and differential pulse voltammetry in CHCl3. The formation of the Watson-Crick H-bonded complex lowers the oxidation potential of the free molecule by 0.34 V, which compares well with the value obtained by DFT/B3LYP/6-311++g** computations.