New Thiophene Derivatives as Antimicrobial Agents

Phenacylbromide derivatives constitute a multilateral group of precursors for the synthesis of numerous heterocycles of organic compounds. Briefly, 5‐(2‐bromo‐acetyl)‐substituted‐thiophene derivative has been used as a synthon for synthesis of new thiophene‐containing compounds through the reaction with nucleophilic nitrogen compounds and thioamides. The suggested structures of the newly synthesized thiophene compounds were confirmed and assured with different spectroscopic tools and with CHN elemental analysis. Additionally, the antimicrobial activity of these thiophene compounds was recorded to investigate their potency against various types of bacteria and fungi. Results showed that these compounds exhibit significant inhibitory activity against the growth of tested bacterial and fungal strains and that some derivatives were more potent than the employed reference drugs.     

Determination of gasoline and diesel residues on wool,silk, polyester and cotton materials by SPME–GC–MS

The identification of ignitable liquids is very important and challenging aspect in arson crime investigations. The detection of gasoline and diesel fuel components using solid phase micro-extraction prior to gas chromatography–mass spectrometry for the forensic analysis of fire debris has been carried out. Previous works show that the absorption characteristics of the substrate are one of the most important factors in determining the evaporation rate of the accelerants. In order to determine the presence of the fuel residues, four of the most common substrate materials were tested in this work; wool, cotton, silk and polyester. The obtained results indicate that both gasoline and diesel fuel accelerants persisted longer on wool and silk than on the other selected substrates. Such information illustrates the influence of fuel persistence times after extinguishing and the best materials to be scanned for ignitable liquids at the fire scene.     

Development and Validation of a Chiral Liquid Chromatographic Assay for Enantiomeric Separation and Quantification of Verapamil in Rat Plasma: Stereoselective Pharmacokinetic Application

A novel, fast and sensitive enantioselective HPLC assay with a new core–shell isopropyl carbamate cyclofructan 6 (superficially porous particle, SPP) chiral column (LarihcShell-P, LSP) was developed and validated for the enantiomeric separation and quantification of verapamil (VER) in rat plasma. The polar organic mobile phase composed of acetonitrile/methanol/trifluoroacetic acid/triethylamine (98:2:0.05: 0.025, v/v/v/v) and a flow rate of 0.5 mL/min was applied. Fluorescence detection set at excitation/emission wavelengths 280/313 nm was used and the whole analysis process was within 3.5 min, which is 10-fold lower than the previous reported HPLC methods in the literature. Propranolol was selected as the internal standard. The S-(−)- and R-(+)-VER enantiomers with the IS were extracted from rat plasma by utilizing Waters Oasis HLB C18 solid phase extraction cartridges without interference from endogenous compounds. The developed assay was validated following the US-FDA guidelines over the concentration range of 1–450 ng/mL (r² ≥ 0.997) for each enantiomer (plasma) and the lower limit of quantification was 1 ng/mL for both isomers. The intra- and inter-day precisions were not more than 11.6% and the recoveries of S-(−)- and R-(+)-VER at all quality control levels ranged from 92.3% to 98.2%. The developed approach was successfully applied to the stereoselective pharmacokinetic study of VER enantiomers after oral administration of 10 mg/kg racemic VER to Wistar rats. It was found that S-(−)-VER established higher C_max and area under the concentration-time curve (AUC) values than the R-(+)-enantiomer. The newly developed approach is the first chiral HPLC for the enantiomeric separation and quantification of verapamil utilizing a core–shell isopropyl carbamate cyclofructan 6 chiral column in rat plasma within 3.5 min after solid phase extraction (SPE).     

Liquid chromatographic high-throughput analysis of the new ultra-short acting hypnotic 'HIE-124' and its metabolite in mice serum using a monolithic silica column

For the first time, a fast, high-performance liquid chromatography (HPLC) method was developed and validated for the simultaneous determination of the new ultra-short hypnotic HIE-124 and its metabolite in mice serum. Each compound, together with carbamazepine (internal standard) was extracted from the serum matrix using liquid-liquid extraction (LLE). Chromatographic resolution of the analytes was performed on a Chromolith Speed Rod monolithic silica column (100 mm × 4.6 mm i.d.) under isocratic conditions using a mobile phase of 65:35 (v/v), 20 mM phosphate buffer (pH 7.0 adjusted with phosphoric acid)-acetonitrile. The elution of the analytes were monitored at 240 nm and conducted at ambient temperature. Because of high column efficiency the mobile phase was pumped at a flow rate of 2.5 mL min(-1). The total run time of the assay was 2 min. The method was validated over the range of 60-2000 ng mL(-1) for HIE-124 and 200-1600 ng mL(-1) for the metabolite (r(2) = 0.99). The limit of detection (LOD) for HIE-124 and its metabolite were 20 ng mL(-1) and 65 ng mL(-1), respectively. The proposed method was validated in compliance with ICH guidelines, in terms of accuracy, precision, limits of detection and quantitation and other aspects of analytical validation. The developed method could be used for the trace analyses of HIE-124 and its metabolite in serum and was finally used for the pharmacokinetic study investigation of HIE-124 in mice serum.     

Pharmacological Efficacy of Ginseng against Respiratory Tract Infections

Respiratory tract infections are underestimated, as they are mild and generally not incapacitating. In clinical medicine, however, these infections are considered a prevalent problem. By 2030, the third most comprehensive reason for death worldwide will be chronic obstructive pulmonary disease (COPD), according to the World Health Organization. The current arsenal of anti-inflammatory drugs shows little or no benefits against COPD. For thousands of years, herbal drugs have been used to cure numerous illnesses; they exhibit promising results and enhance physical performance. Ginseng is one such herbal medicine, known to alleviate pro-inflammatory chemokines and cytokines (IL-2, IL-4, IFN-γ, TNF-α, IL-5, IL-6, IL-8) formed by macrophages and epithelial cells. Furthermore, the mechanisms of action of ginsenoside are still not fully understood. Various clinical trials of ginseng have exhibited a reduction of repeated colds and the flu. In this review, ginseng’s structural features, the pathogenicity of microbial infections, and the immunomodulatory, antiviral, and anti-bacterial effects of ginseng were discussed. The focus was on the latest animal studies and human clinical trials that corroborate ginseng’s role as a therapy for treating respiratory tract infections. The article concluded with future directions and significant challenges. This review would be a valuable addition to the knowledge base for researchers in understanding the promising role of ginseng in treating respiratory tract infections. Further analysis needs to be re-focused on clinical trials to study ginseng’s efficacy and safety in treating pathogenic infections and in determining ginseng-drug interactions.     

Synthesis,Characterization, and Biological Evaluation of Some Novel Pyrazolo[5,1-b]thiazole Derivatives as Potential Antimicrobial and Anticancer Agents

The pharmacological activities of thiazole and pyrazole moieties as antimicrobial and anticancer agents have been thoroughly described in many literature reviews. In this study, a convenient synthesis of novel pyrazolo[5,1-b]thiazole-based heterocycles was carried out. The synthesized compounds were characterized by IR, ¹H and ¹³C NMR spectroscopy and mass spectrometry. Some selected examples were screened and evaluated for their antimicrobial and anticancer activities and showed promising results. These products could serve as leading compounds in the future design of new drug molecules.     

Synthesis and applications of silver nanoparticles

Over the past few decades, nanoparticles of noble metals such as silver exhibited significantly distinct physical, chemical and biological properties from their bulk counterparts. Nano-size particles of less than 100 nm in diameter are currently attracting increasing attention for the wide range of new applications in various fields of industry. Such powders can exhibit properties that differ substantially from those of bulk materials, as a result of small particle dimension, high surface area, quantum confinement and other effects. Most of the unique properties of nanoparticles require not only the particles to be of nano-sized, but also the particles be dispersed without agglomeration. Discoveries in the past decade have clearly demonstrated that the electromagnetic, optical and catalytic properties of silver nanoparticles are strongly influenced by shape, size and size distribution, which are often varied by varying the synthetic methods, reducing agents and stabilizers. Accordingly, this review presents different methods of preparation silver nanoparticles and application of these nanoparticles in different fields.     

A profound density functional theory study to unravel the spectroscopic and molecular properties of two Flavanols differing in α-pyrone ring position

A comprehensive theoretical model was designed for two new flavanols that have been reported from Glycosmis pentaphylla, differing in the placement of α-pyrone ring. The density functional theory (DFT) approach was utilized for computing different properties of these compounds to validate the experimental findings and stereochemical assignments. Electronic properties, geometric parameters, frontier molecular orbitals (FMOs), molecular electrostatic potential (MESP), and natural bond orbital analysis were performed for the first time at the PBE0-D3BJ/def2-TZVP level of theory for the compounds under study. The simulated vibrational frequencies for compounds 1 and 2 were computed and compared with the experimental results. nuclear magnetic resonance (NMR) (¹H and ¹³C) chemical shift values were computed at the PBE0-D3BJ/def2-TZVP/SMD_DMSO level of theory and showed a very good agreement with the experimental results for both the compounds. The electronic circular dichroism (ECD) and ultraviolet–visible (UV) spectra for both the compounds were obtained using time-dependent DFT in methanol, whose results exhibited excellent correlation with experimental data. The intermolecular interaction effect on geometric parameters, vibrational frequencies, and electronic properties were studied for the first time.     

Synthesis of antimicrobial agents of tetra-substituted thiophenes from ethyl 5-(2-bromoacetyl)-4-phenyl-2-(phenylamino)thiophene-3-carboxylate

5-(2-Bromoacetyl)-2,3,4-trisubstituted-thiophene was used as a synthetic intermediate to prepare a series of thiophene derivatives and thiophene incorporating oxazole, imidazole, thiazole, pyrrole, and pyridine rings via substitution and cyclo-condensation reactions. The data were extracted from the spectra of the resulting products confirmed their suggested structures. The newly synthesized compounds were screened to evaluate their in vitro antimicrobial activity vs several positive and negative gram bacteria and fungi. The screening data revealed that the thiophene derivative 7a , incorporating a thiazole ring, displayed strong activity against all tested microorganisms when compared with the antibiotics used.