(P,C) Cyclometalated Gold(III) Complexes: Highly Active Catalysts for the Hydroarylation of Alkynes

The first catalytic application of well‐defined (P,C) cyclometalated gold(III) complexes is reported. The bench‐stable bis(trifluoroacetyl) complexes 2 a , b perform very well in the intermolecular hydroarylation of alkynes. The reaction is broad in scope, it proceeds within few hours at 25 °C at catalytic loadings of 0.1–5 mol %. The electron‐rich arene adds across the C≡C bond with complete regio‐ and stereo‐selectivity. The significance of well‐defined gold(III) complexes and ligand design are highlighted in a powerful but challenging catalytic transformation.     

Diversity of Neuropeptide Cell-Cell Signaling Molecules Generated by Proteolytic Processing Revealed by Neuropeptidomics Mass Spectrometry

Neuropeptides are short peptides in the range of 3–40 residues that are secreted for cell-cell communication in neuroendocrine systems. In the nervous system, neuropeptides comprise the largest group of neurotransmitters. In the endocrine system, neuropeptides function as peptide hormones to coordinate intercellular signaling among target physiological systems. The diversity of neuropeptide functions is defined by their distinct primary sequences, peptide lengths, proteolytic processing of pro-neuropeptide precursors, and covalent modifications. Global, untargeted neuropeptidomics mass spectrometry is advantageous for defining the structural features of the thousands to tens of thousands of neuropeptides present in biological systems. Defining neuropeptide structures is the basis for defining the proteolytic processing pathways that convert pro-neuropeptides into active peptides. Neuropeptidomics has revealed that processing of pro-neuropeptides occurs at paired basic residues sites, and at non-basic residue sites. Processing results in neuropeptides with known functions and generates novel peptides representing intervening peptide domains flanked by dibasic residue processing sites, identified by neuropeptidomics. While very short peptide products of 2–4 residues are predicted from pro-neuropeptide dibasic processing sites, such peptides have not been readily identified; therefore, it will be logical to utilize metabolomics to identify very short peptides with neuropeptidomics in future studies. Proteolytic processing is accompanied by covalent post-translational modifications (PTMs) of neuropeptides comprising C-terminal amidation, N-terminal pyroglutamate, disulfide bonds, phosphorylation, sulfation, acetylation, glycosylation, and others. Neuropeptidomics can define PTM features of neuropeptides. In summary, neuropeptidomics for untargeted, global analyses of neuropeptides is essential for elucidation of proteases that generate diverse neuropeptides for cell-cell signaling.

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Stability-Indicating Methods for the Determination of Cimetidine Using Derivative and Fourier-Transform Infrared Spectrophotometry

Abstract

Two different techniques, that is, second (D₂) and third (D₃) derivative spectrophotometry and fourier transform infrared (FTIR) Spectrophotometry, are investigated for the selective determination of the intact cimetidine in presence of up to 25% and 75% of its degradates, respectively. The procedures determine 2–10 jag ml^?1 at 224 nm and 217.5 nm by D₂ and D₃, respectively, and 1–6 mg per 250 mg in K Br by the FTIR with mean accuracies of 100.0 ± 1.07%, 100.5 ± 0.87% and 100.3 ± 1.16%, respectively. The drug is successfully analysed in its pharmaceutical formulations.

     

Two level hierarchical time minimizing transportation problem

A two level hierarchical balanced time minimizing transportation problem is considered in this paper. The whole set of source-destination links consists of two disjoint partitions namely Level-I links and Level-II links. Some quantity of a homogeneous product is first shipped from sources to destinations by Level-I decision maker using only Level-I links, and on its completion the Level-II decision maker transports the remaining quantity of the product in an optimal fashion using only Level-II links. Transportation is assumed to be done in parallel in both the levels. The aim is to find that feasible solution for Level-I decision maker corresponding to which the optimal feasible solution for Level-II decision maker is such that the sum of shipment times in Level-I and Level-II is the least. To obtain the global optimal feasible solution of this non-convex optimization problem, related balanced time minimizing transportation problems are defined. Based upon the optimal feasible solutions of these related problems, standard cost minimizing transportation problems are constructed whose optimal feasible solutions provide various pairs for shipment times for Level-I and Level-II decision makers. The best out of these pairs is finally selected. Being dependent upon solutions of a finite number of balanced time minimizing and cost minimizing transportation problems, the proposed algorithm is a polynomial bound algorithm. The developed algorithm has been implemented and tested on a variety of test problems and performance is found to be quite encouraging.     

A Cadmium Coordination Polymer Based on Phosphate Clusters: Synthesis,Crystal Structure,Electrochemical Investigation and Antibacterial Activity

A new d¹⁰ coordination polymer, \(\left\{ {\left( {{\text{C}}_{5} {\text{H}}_{14} {\text{N}}_{2} } \right)_{2} \left[ {{\text{Cd}}\left( {\left( {{\text{P}}_{6} {\text{O}}_{18} } \right)\left( {{\text{H}}_{2} {\text{O}}} \right)_{2} } \right)} \right] \cdot 6{\text{H}}_{2} {\text{O}}} \right\}_{n}\), was prepared and characterized by X-ray diffraction, IR-Raman spectroscopy, thermal analysis and cyclic voltammetry. The crystal structure determination reveals that the phosphate anions alternate with the cadmium octahedral to form an anionic coordination polymer extending along [001] direction. The double protonated homopiperazine cations and the water molecules ensure the interconnection between polymers and thus giving rise to three dimensional supramolecular networks. By means of cyclic voltammetry, it is shown that whilst the reduction of the complexed Cd²⁺ occurs with a biggest difficulty than this of its free form, the anodic oxidation of the heterocyclic N donor piperazine became quite easy, when it is displayed as a counterpart diprotonated cation, between the anionic layers of \(\left[ {{\text{Cd}}({\text{P}}_{6} {\text{O}}_{18} )({\text{H}}_{2} {\text{O}})_{2} )} \right]_{\text{n}}^{{4{\text{n}} - }}\). The antibacterial activity of the coordination polymer is also discussed.     

Modulation of antioxidant systems by subchronic exposure to the aqueous extract of leaves from Achillea millefolium L. in rats

We determined the effects of subchronic exposure to aqueous extract of leaves from Achillea millefolium (AE) on enzyme- and non-enzyme-dependent antioxidant systems in rats. Seven days treatment with AE (1 g/kg/twice a day, p.o.) altered the reduced glutathione (GSH) levels and antioxidant enzyme activities in several organs of the animals. Amount of GSH in uterus was increased (73%) while in kidneys it was decreased (23%). Besides, NAD(P)H quinone oxidoreductase 1 (NQO1) activity was increased in forestomach (26%) and in liver (64%), while glutathione S-transferase activity was decreased in the forestomach (32%) and increased in the liver (41%), kidney (35%) and uterus (37%). In preliminary experiments targeting the interaction of AE with acetaminophen (600 mg/kg, p.o.), we observed augmentation of acetaminophen-induced increase of the plasmatic alanine aminotransaminase, aspartate aminotransaminase and lactate dehydrogenase. Overall, the results indicate a potential toxic interaction of AE compounds with xenobiotics that use the glutathione pathway.     

Determination of volatile organic compounds in the dried leaves of Salvia species by solid-phase microextraction coupled to gas chromatography mass spectrometry

Salvia spp. are used throughout the world both for food and pharmaceutical purposes. In this study, a method involving headspace solid-phase microextraction combined with gas chromatography–mass spectrometry was developed, to establish the volatiles profile of dried leaves of four Iranian Salvia spp.: Salvia officinalis L., Salvia leriifolia Benth, Salvia macrosiphon Boiss. and two ecotypes of Salvia reuterana Boiss. A total of 95 volatiles were identified from the dried leaves of the five selected samples. Specifically, α-thujone was the main component of S. officinalis L. and S. macrosiphon Boiss. (34.40 and 17.84%, respectively) dried leaves, S. leriifolia Benth was dominated by β-pinene (27.03%), whereas α-terpinene was the major constituent of the two ecotypes of S. reuterana Boiss. (21.67 and 13.84%, respectively). These results suggested that the proposed method can be considered as a reliable technique for isolating volatiles from aromatic plants, and for plant differentiation based on the volatile metabolomic profile.