DFT Protocol for EPR prediction of paramagnetic Cu(II) complexes and application to protein binding sites

With the aim to provide a general protocol to interpret electron paramagnetic resonance (EPR) spectra of paramagnetic copper(II) coordination compounds, density functional theory (DFT) calculations of spin Hamiltonian parameters g and A for fourteen Cu(II) complexes with different charges, donor sets, and geometry were carried out using ORCA software. The performance of eleven functionals was tested, and on the basis of the mean absolute percent deviation (MAPD) and standard deviation (SD), the ranking of the functionals for Az is: B3LYP > B3PW91 ~ B3P86 > PBE0 > CAM-B3LYP > TPSSh > BH and HLYP > B2PLYP > MPW1PW91 > ω-B97x-D » M06; and for gz is: PBE0 > BH and HLYP > B2PLYP > ω-B97x-D > B3PW91~B3LYP~B3P86 > CAM-B3LYP > TPSSh~MPW1PW91 » M06. With B3LYP the MAPD with respect to A exp tl z is 8.6% with a SD of 4.2%, while with PBE0 the MAPD with respect to g exp tl z is 2.9% with a SD of 1.1%. The results of the validation confirm the fundamental role of the second order spin-orbit contribution to Az. The computational procedure was applied to predict the values of gz and Az of the adducts formed by Cu(II) with albumin and two fragments of prion protein, 106-126 and 180-193

Influence of temperature on the equilibria of oxidovanadium(IV) complexes in solution.

The equilibria at different temperatures of VIVOL2complexes were investigated in order to elucidate their interaction with proteins

Biospeciation of Potential Vanadium Drugs of Acetylacetonate in the Presence of Proteins

Among vanadium compounds with potential medicinal applications, [V IV O(acac)] is one of the most promising for its antidiabetic and anticancer activity. In the organism, however, interconversion of the oxidation state to +III and +V and binding to proteins are possible. In this report, the transformation of V III (acac), V IV O(acac), and V V O(acac) after the interaction with two model proteins, lysozyme (Lyz) and ubiquitin (Ub), was studied with ESI-MS (ElectroSpray Ionization-Mass Spectroscopy), EPR (Electron Paramagnetic Resonance), and computational (docking) techniques. It was shown that, in the metal concentration range close to that found in the organism (15-250 μM), V III (acac) is oxidized to V IV O(acac) + and V IV O(acac), which-in their turn-interact with proteins to give n [V IV O(acac)]-Protein and n [V IV O(acac)]-Protein adducts. Similarly, the complex in the +IV oxidation state, V IV O(acac), dissociates to the mono-chelated species V IV O(acac) + which binds to Lyz and Ub. Finally, V V O(acac) undergoes complete dissociation to give the 'bare' V V O ion that forms adducts n [V V O]-Protein with n = 1-3. Docking calculations allowed the prediction of the residues involved in the metal binding. The results suggest that only the V IV O complex of acetylacetonate survives in the presence of proteins and that its adducts could be the species responsible of the observed pharmacological activity, suggesting that in these systems V IV O 2+ ion should be used in the design of potential vanadium drugs. If V III or V V O potential active complexes had to be designed, the features of the organic ligand must be adequately modulated to obtain species with high redox and thermodynamic stability to prevent oxidation and dissociation

DFT Protocol for EPR prediction of paramagnetic Cu(II) complexes and application to protein binding sites

With the aim to provide a general protocol to interpret electron paramagnetic resonance (EPR) spectra of paramagnetic copper(II) coordination compounds, density functional theory (DFT) calculations of spin Hamiltonian parameters g and A for fourteen Cu(II) complexes with different charges, donor sets, and geometry were carried out using ORCA software. The performance of eleven functionals was tested, and on the basis of the mean absolute percent deviation (MAPD) and standard deviation (SD), the ranking of the functionals for Az is: B3LYP > B3PW91 ~ B3P86 > PBE0 > CAM-B3LYP > TPSSh > BH and HLYP > B2PLYP > MPW1PW91 > ω-B97x-D » M06; and for gz is: PBE0 > BH and HLYP > B2PLYP > ω-B97x-D > B3PW91~B3LYP~B3P86 > CAM-B3LYP > TPSSh~MPW1PW91 » M06. With B3LYP the MAPD with respect to A exp tl z is 8.6% with a SD of 4.2%, while with PBE0 the MAPD with respect to g exp tl z is 2.9% with a SD of 1.1%. The results of the validation confirm the fundamental role of the second order spin-orbit contribution to Az. The computational procedure was applied to predict the values of gz and Az of the adducts formed by Cu(II) with albumin and two fragments of prion protein, 106-126 and 180-193

Immunofluorescence of the tubulin system in human skin fibroblasts in Werner's syndrome, Kaposi sarcoma, and psoriasis

Reduced survival of skin fibroblasts in cell cultures and laterations of fibroblast gene products, such as surface antigens HLA2 and HLA9 and a cytoplasmic enzyme, glucose-6-phosphate dehydrogenase, have been recently demonstrated in a patient affected by Werner's syndrome. In order to investigate the morphology of the fibroblasts from patients affected by Werner's syndrome it was decided to study the tubulin system in primary cell cultures. Microtubules are tubular structures, 20-25 nm wide, and are thought to play a significant role in cell morphology and in the regulation of intracellular movements. Fibroblast cultures from normal subjects and from patients affected by Kaposi's sarcoma and by psoriasis were studied as controls

The Cytoskeleton of hydatid cyst cultured cells and its sensitivity to inhibitors

Cell cultures obtained from the germinal layer of hydatid cysts of the parasitic tapeworm Echinococcus granulosus were characterized with respect to their microtubule and microfilament systems. These were stained using monospecific antibodies against tubulin from sea urchin spermatozoa or sheep brain and against Dictyostelium discoideum actin as well as rhodamine conjugated phalloidin. The results show that the distribution of microtubules nad actin containing fibres of these cells is remarkably similar to that of mammalian cells both during interphase and mitosis. Hydatid cells, however, could not be stained with a specific antivimentin antibody. Indirect immunofluorescence with antitubulin antibodies of inhibitor treated cells shows that hydatid cell microtubules are sensitive to several antimicrotubular drugs including benzimidazole derivatives, colchicine, vinblastine, and griseofulvin

Polymeric nanoparticles encapsulating white tea extract for nutraceutical application

With the aim to obtain controlled release and to preserve the antioxidant activity of the polyphenols, nanoencapsulation of white tea extract into polymeric nanoparticles (NPs) based on poly(ε-caprolactone) (PCL) and alginate was successfully performed. NPs were prepared by nanoprecipitation method and were characterized in terms of morphology and chemical properties. Total polyphenols and catechins contents before and after encapsulation were determined. Moreover, in vitro release profiles of encapsulated polyphenols from NPs were investigated in simulated gastrointestinal fluids. The antioxidant activity and stability of encapsulated extract were further evaluated. Interestingly, NPs released 20% of the polyphenols in simulated gastric medium, and 80% after 5 h at pH 7.4, showing a good capacity to control the polyphenols delivery. Furthermore, DPPH• assay confirmed that white tea extract retained its antioxidant activity and NPs protected tea polyphenols from degradation, thus opening new perspectives for the exploitation of white tea extract-loaded NPs for nutraceutical applications

Effect of chitosan concentration on PLGA microcapsules for controlled release and stability of resveratrol

The polyphenols as nutraceutical and therapeutic agents are gaining growing interest for their beneficial effects and potential in human health. In order to protect their scaffolds and functionality, and to improve the bioavailability, the microencapsulation can represent a promising strategy. This study reports on the formulation of the natural resveratrol (RSV) into microcapsules (MCs) prepared by using different concentrations of chitosan (CS) and poly(D,L-lactic-co-glycolic acid) (PLGA) as polymeric matrix. MCs were prepared by W/O/W double emulsion method and characterized in terms of morphology, size, encapsulation efficiency, physicochemical and thermal properties. RSV release behavior from MCs was evaluated under simulated gastrointestinal fluids, and the long term stability was monitored at different storage conditions. MCs resulted to have spherical shape and different morphology, with size ranging from 11 to 20 μm, and encapsulation efficiencies of 40–52%, depending on the CS concentration. Moreover, MCs containing CS exhibited a significant lower release of RSV than those containing only PLGA. Furthermore, all tested formulations were able to ensure a good retention and stability of encapsulated RSV until 6 months. In summary, CS/PLGA MCs can be proposed as an attractive delivery system to control the release and long term protection of RSV

Data mining as a predictive model for <i>Chelidonium majus</i> extracts production

Chelidonium majus L. (C. majus) is a herbaceous perennial plant of the Papaveraceae family. C. majus is rich of benzylisoquinoline alkaloids: protopine, chelidonine, stylopine, coptisine, berberine, sanguinarine and chelerythrine. Each one of them is endowed with a peculiar pharmacological/toxicological profile. Different C. majus extracts, obtained from different plant parts and under different extraction conditions, contain the above-mentioned alkaloids in different amounts with regard to each other. Consequently they are expected to exert an extremely wide range of therapeutic and/or toxic effects. In this paper, data mining techniques, such as multi-linear regressions and Gaussian processes, were efficiently used to develop a fast and easy approach by which it is possible to predict how different parts of the plant and different extraction conditions lead to C. majus extracts characterized by different chemical composition, in terms of alkaloid contents. In particular, for each alkaloid a model was developed which correlates specific parts of the plant and extraction conditions with the quantity of the desired alkaloid. All models were statistically validated for their goodness of fit and robustness and are characterized by correlation coefficient values (R2) up to 0.9618 and cross-validated correlation coefficient values (LOO-CV R2) up to 0.8343. Thus, each model can help in the selection of the proper parts of the plant and extraction conditions to be exploited in order to obtain a particular extract enriched of a particular alkaloid and endowed with desired properties. Another advantage is that the data mining approach presented here could even be applied to other plants, and for other chemical entities

Combination anticancer endowed with antitumor activity, comprising alkaloids of chelidonium majus

The invention relates to a combination having antitumor activity, wherein an agent having antineoplastic activity, such as gemcitabine or temozolomide, is associated with an alkaloid of Chelidonium majus (C. majus), such as berbenne, chelidonine or protopine