THERMODYNAMICS OF QUERCETIN SOLVATION IN WATER-DIMETHYLSULFOXIDE SOLVENT

The distribution coefficients of quercetin (QCT) in water-dimethylsulfoxide solvents with a content of dimethylsulfoxide from 0.0 to 0.5 mol. fr. were determined by the method of interfacial distribution of the substance between two immiscible phases: aqueous or water-dimethylsulfoxide solution and n-hexane at 298.2 K. The distribution coefficients are less than one, which indicates a better solvation of quercetin in water and a water-dimethylsulfoxide solvent than in hexane. Changes in the distribution coefficients of quercetin are not correlated with a gradual increase in the content of dimethylsulfoxide (DMSO) in the solvent. Using the obtained values of the distribution coefficients, we calculated the changes in the Gibbs energy of re-solvation of quercetin in water-dimethylsulfoxide solvents. The dependence of the Gibbs energy of QCT re-solvation on the solvent composition has an extreme form with a minimum in the range of DMSO concentrations corresponding to 0.3 mol. fr. A comparative analysis of the effect of a water-dimethylsulfoxide solvent on the change in Gibbs energy of re-solvation of quercetin, nicotinamide and nicotinic acid was carried out. In the case of both nicotinamide and nicotinic acid, an extreme change is observed in the Gibbs energy of re-solvation of particles with a maximum in the region with a low content of non-aqueous component XDMSO ≈ 0.1 mol. fr. The main contribution to the weakening of the solvation of nicotinamide and nicotinic acid is due to the enthalpy component, and with increasing concentration of dimethylsulfoxide there is an increase in the contribution of entropy to the change in the Gibbs energy transfer. An extreme change in the Gibbs energy transfer of quercetin suggests that the minimum on the dependence ∆trGº(QCT) = F(χDMSO) is also a consequence of a change in the prevailing thermodynamic factor in the solvate state of quercetin.

Extraction of Lipids from Liquid Biological Samples for High-Throughput Lipidomics

Extraction of the lipid fraction is a key part of acquiring lipidomics data. High-throughput lipidomics, the extraction of samples in 96w plates that are then run on 96 or 384w plates, has particular requirements that mean special development work is needed to fully optimise an extraction method. Several methods have been published as suitable for it. Here, we test those methods using four liquid matrices: milk, human serum, homogenised mouse liver and homogenised mouse heart. In order to determine the difference in performance of the methods as objectively as possible, we used the number of lipid variables identified, the total signal strength and the coefficient of variance to quantify the performance of the methods. This showed that extraction methods with an aqueous component were generally better than those without for these matrices. However, methods without an aqueous fraction in the extraction were efficient for milk samples. Furthermore, a mixture containing a chlorinated solvent (dichloromethane) appears to be better than an ethereal solvent (tert-butyl methyl ether) for extracting lipids. This study suggests that a 3:1:0.005 mixture of dichloromethane, methanol and triethylammonium chloride, with an aqueous wash, is the most efficient of the currently reported methods for high-throughput lipid extraction and analysis. Further work is required to develop non-aqueous extraction methods that are both convenient and applicable to a broad range of sample types.

Detection of Synthetic Drugs as Adulterants in Natural and Herbal Slimming Products by LC-ESI-MS/MS with Polarity Switching

The purpose of this study was to develop an LC-tandem MS method for the simultaneous detection of common synthetic drugs as adulterants in natural and herbal slimming products. Sixteen drugs belonging to a wide range of pharmaceutical classes were studied. Included in the list of drugs were anorexics, anxiolytics, antidepressants, diuretics, laxatives, and stimulants. The method used a C18 column (4.6 × 50 mm and 1.8 μm particle size). Separation of the drugs was achieved by gradient elution using 4 mM ammonium formate in water + 0.1% formic acid as the aqueous component and 4 mM ammonium formate in methanol + 0.1% formic as the organic component of the mobile phase. As not all of the analytes ionized in the positive mode, the mass spectrometer was operated in the electrospray ionization mode with polarity switching. The samples were extracted with methanol and the use of 50% acetonitrile in water and 50% methanol in water were investigated as diluents for injection into the LC-MS system. Utilizing both diluents, the validation parameters including accuracy, precision, LOD, and LOQ were assessed. The validation results and utilization of the method to analyze a variety of weight-loss supplements indicate that the two diluents give similar results and can be used interchangeably. This knowledge provides the user with the option of selecting either diluent for sample preparation depending on the sample matrix without having to revalidate the method. The method was applied to the analysis of weight-loss supplements available in local pharmacies, herbal pharmacies, and over the Internet.

GREEN SYNTHESIS OF SILVER NANO PARTICLES

The research was carried out to investigate the synthesis of silver nano particles. The silver nano particles have wide tremendous application in the therapeutics, antimicrobials, diagnostics, catalysis, micro-electronics and high sensitivity biomolecular detection. Silver nano particles grow in a single-step method, at room temperature, and with no addition of external energy. The silver nanoparticles were synthesized from silver nitrate aqueous solution through a simple, eco-friendly and cost effective course using the leaf broth of the Oscimum sanctum, Azadirachtaindica and LawsoniaInermis (kadvi mehndi), therefore calling it green synthesis. The Synthesized AgNP was confirmed by sampling the aqueous component at different time intervals and the absorption maxima was scanned by UV-Vis spectrometry and Particle Size Distribution (PSD). Based on PSD, the particles were further characterized by Scanning Electron Microscope. Synthesized AgNP was confirmed at 531,540and 543 nm. Among the total percentage of size distribution, D-50 value, which is 50% size distribution, was taken into consideration, where the size of the nanoparticle was established to 0.135µm. Further research is going on with reference to the synthesized nanoparticles.

Microalterations in the third eyelid gland of dogs with keratoconjunctivits sicca secondary to distemper

Keratoconjunctivitis sicca is characterized by qualitative or quantitative abnormalities in the aqueous component of the tear film and is frequent in dogs with distemper. Twenty-eight third eyelid glands of end-stage dogs that died from distemper were analyzed by light microscopy. Keratoconjunctivitis sicca was diagnosed based on ophthalmic findings regarding alterations in the ocular surface and by the Schirmer tear test. The excised glands were fixed in 10% buffered formalin and processed for embedding in paraffin. The blocks were cut into 4µm sections and the sections were stained with hematoxylin-eosin and Masson's trichrome. Analysis revealed tubuloacinar gland atrophy, thickening of connective tissue, and mild to intense inflammatory exudation mainly characterized by the presence of plasma cells and histiocytes and by compensatory hypertrophy of some glands. The glandular lumen was hypertrophied and contained shedded epithelial cells, polymorphonuclear cells and red blood cells, in addition to mucus.

Canine lacrimal and third eyelid superficial glands’ macroscopic and morphometric characteristics

The lacrimal and third eyelid superficial glands produce the aqueous component of the preocular tear film. In this research, morphologic and morphometric assessments of the parenchyma and stroma of both lacrimal glands of healthy adult mongrel dogs were performed. Both lacrimal and third eyelid glands of fourteen dogs were collected, summing fifty-six samples. The macroscopic and morphometric data were statistically analyzed, according to the glandular type (lacrimal and third eyelid superficial glands) and sexual dimorphism (male or female). The lacrimal glands were significantly larger and longer than the superficial glands of the third eyelid. Expressive morphometric differences of interlobular duct, lymphocytic infiltration, interlobular vessels and secretory parenchyma between the two glandular types were encountered. The lacrimal glands from the male subjects were significantly larger than those from female ones, as well as the superficial glands of the third eyelid were thicker. The higher lymphocyte infiltration and poorer secretor parenchyma in female dogs may be one of the reasons for the higher incidence of keratoconjunctiviti sicca (KCS) in such canine population.