Protective Effects of Thymoquinone,an Active Compound of Nigella sativa,on Rats with Benzo(a)pyrene-Induced Lung Injury through Regulation of Oxidative Stress and Inflammation

Benzopyrene [B(a)P] is a well-recognized environmental carcinogen, which promotes oxidative stress, inflammation, and other metabolic complications. In the current study, the therapeutic effects of thymoquinone (TQ) against B(a)P-induced lung injury in experimental rats were examined. B(a)P used at 50 mg/kg b.w. induced lung injury that was investigated via the evaluation of lipid profile, inflammatory markers, nitric oxide (NO), and malondialdehyde (MDA) levels. B(a)P also led to a decrease in superoxide dismutase (SOD) (34.3 vs. 58.5 U/mg protein), glutathione peroxidase (GPx) (42.4 vs. 72.8 U/mg protein), catalase (CAT) (21.2 vs. 30.5 U/mg protein), and total antioxidant capacity compared to normal animals. Treatment with TQ, used at 50 mg/kg b.w., led to a significant reduction in triglycerides (TG) (196.2 vs. 233.7 mg/dL), total cholesterol (TC) (107.2 vs. 129.3 mg/dL), and inflammatory markers and increased the antioxidant enzyme level in comparison with the group that was administered B(a)P only (p < 0.05). B(a)P administration led to the thickening of lung epithelium, increased inflammatory cell infiltration, damaged lung tissue architecture, and led to accumulation of collagen fibres as studied through haematoxylin and eosin (H&E), Sirius red, and Masson’s trichrome staining. Moreover, the recognition of apoptotic nuclei and expression pattern of NF-κB were evaluated through the TUNEL assay and immunohistochemistry, respectively. The histopathological changes were found to be considerably low in the TQ-treated animal group. The TUNEL-positive cells increased significantly in the B(a)P-induced group, whereas the TQ-treated group showed a decreased apoptosis rate. Significantly high cytoplasmic expression of NF-κB in the B(a)P-induced group was seen, and this expression was prominently reduced in the TQ-treated group. Our results suggest that TQ can be used in the protection against benzopyrene-caused lung injury.     

Sol–gel synthesis and characterization of conducting polythiophene/tin phosphate nano tetrapod composite cation-exchanger and its application as Hg(II) selective membrane electrode

Nano tetrapod based on conducting polythiophene (PTh) and tin-phosphate (SnP) were synthesized by in situ chemical oxidative polymerization. The morphology of the resulting polythiophene tinphosphate composite was characterized by elemental analysis, fourier transform infrared spectroscopy, thermogravimetric analysis, powder X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The physico-chemical characterization carried out on the composite showed that SnP was modified by conducting PTh with an enhancement of various properties. On the basis of highest distribution coefficient values for Hg(II), the composite was also used for the preparation of Hg(II) selective membrane electrode. The electrode showed working concentration range of 1 × 10^?1 to 1 × 10^?7 with Nernstian slope of 29.29 mV per decade change in concentration and the electrode may be used for wide working pH range of 4–8 having quick response time about 23 s. The life of electrode is 4 months without any notable drift in potential.     

Voltammetry coupled to mass spectrometry in the presence of isotope O labeled water for the prediction of oxidative transformation pathways of activated aromatic ethers: Acebutolol

The coupling between an electrochemical cell (EC) and a mass spectrometer (MS) is a useful screening tool (EC-MS) to study the oxidative transformation pathways of various electroactive species. For that purpose, we showed that the EC-MS method, carried out in the presence and absence of isotope ¹⁸O labeled water leads not only to a fast identification of oxidation products but also leads to a fast elucidation of the mechanism pathway reaction. We examined herein the case of the electrochemical hydrolysis of activated aromatic ether. Acebutolol (β-blockers) was selected herein as model of activated aromatic ether, and its electrochemical oxidation was examined in both the presence and absence of isotope ¹⁸O labeled water. To elucidate electrochemical hydrolysis pathway reaction: O-dealkylation or O-dealkoxylation, our approach was used to prove its applicability. The electrochemical oxidation mechanism was then elucidated showing an O-dealkoxylation reaction. In addition, density functional theory (DFT) calculations fully support the experimental conclusions.     

Oxidation of Aromatic Amines to Quinones by Iodic Acid under Microwave Irradiation in the Presence of Montmorillonite K10 and Silica Gel

Summary. A variety of aromatic amines are oxidized to their corresponding quinones in excellent yields by supported iodic acid under microwave irradiation and solvent free conditions.     

An expedient esterification of aromatic carboxylic acids using sodium bromate and sodium hydrogen sulfite

Treatment of aromatic carboxylic acids and substituted toluenes with a mixture of sodium bromate and sodium hydrogen sulfite in a two-phase system gave the corresponding esters in good yield. The intermediate α-brominated toluene was formed by the in situ generated hypobromous acid. The α-bromotoluene underwent an intermolecular nucleophilic substitution reaction with aromatic carboxylic acids present in the reaction mixture to afford the corresponding esters.     

Rapid one-step synthesis, characterization and functionalization of silica coated gold nanoparticles

This paper describes a rapid, simple and one-step method for preparing silica coated gold (Au@SiO₂) nanoparticles with fine tunable silica shell thickness and surface functionalization of the prepared particles with different groups. Monodispersed Au nanoparticles with a mean particle size of 16 nm were prepared by citrate reduction method. Silica coating was carried out by mixing the as prepared Au solution, tetraethoxysilane (TEOS) and ammonia followed by microwave (MW) irradiation. Although there are several ways of coating Au nanoparticles with silica in the literature, each of these needs pre-coating step as well as long reaction duration. The present method is especially useful for giving the opportunity to cover the colloidal Au particles with uniform silica shell within very short time and forgoes the use of a silane coupling agent or pre-coating step before silica coating. Au@SiO₂ nanoparticles with wide range of silica shell thickness (5-105 nm) were prepared within 5 min of MW irradiation by changing the concentration of TEOS only. The size uniformity and monodispersity were found to be better compared to the particles prepared by conventional methods, which were confirmed by dynamic light scattering and transmission electron microscopic techniques. The prepared Au@SiO₂ nanoparticles were further functionalized with amino, carboxylate, alkyl groups to facilitate the rapid translation of the nanoparticles to a wide range of end applications. The functional groups were identified by XPS, and zeta potential measurements.     

New sterically unhindered benzoquinonemonoimines

We accidentally found that the F→OH conversion by direct hydroxylation of electron deficient aryls above 150 °C allows the isolation of the precursors of novel quinonemonoimines 9, previously unknown.     

Synthesis of the southern furan segment of furanocembranoids

Abstract

A convergent synthesis of the southern furan segment of novel furanocembranoids from Croton oblongifolius has been accomplished involving silver-catalyzed cyclization of alkynyl diol as the key step towards 2, 5-disubstituted furan ring formation.     

Synthesis and Biological Evaluation of Glycosides and Acyclic Nucleosides Derived 2‐Oxonicotinonitriles

Synthesis and biological evaluations of a series of 2‐oxonicotinonitriles (2‐ONNs) derivatives are described. Incorporation of branching and solubilizing groups to the 2‐ONN derivative 7 was attained by coupling with several organo‐halides/alkylating agents including three glycosyl bromides under basic conditions. Coupling of 2‐ONNs occurred mainly at the ring nitrogen position and to a lesser extent at the 2‐oxo position giving the O‐alkylated products. Alkylated ONNs and free nucleosides/glycosides derived from the 2‐ONN derivative 7 were tested for their antibacterial, antifungal, and antiviral activities. N‐propargyl and N‐allyl derivatives 23 and 25 showed significant anti‐SARS‐CoV. The N‐butylacetate and O‐allyl derivatives 18 and 26 showed potent antibacterial activities against both Gram‐positive (Staphylococcus aureus, Micrococci luteus) and Gram‐negative (Pseudomonas aeruginosa, Escherichia coli) bacterial strains. The N‐glucoside derivative 8 showed significant antifungal activity.     

Method for Visible Light‐Induced Photocatalytic Degradation of Methylparaben in Water Using Nanostructured Ag/AgBr@m‐WO3

An efficient method of photocatalytic degradation of methylparaben in water using Ag nanoparticles (NPs) loaded AgBr‐mesoporous‐WO₃ composite photocatalyst (Ag/AgBr@m‐WO₃), under visible light is presented. In this process, quantification of methylparaben in water was carried out by high‐performance liquid chromatography (HPLC) and the HPLC results showed a significant reduction of methylparaben in water due to the enhanced of photocatalytic degradation efficiency of Ag/AgBr@m‐WO₃. For the material synthesis, highly ordered mesoporous‐WO₃ (m‐WO₃) was initially synthesized by sol–gel method and AgBr nanoparticles (NPs) were subsequently introduced in the pores of m‐WO₃, and finally, the Ag nanoparticles were introduced by light irradiation. The enhanced photocatalytic degradation of methylparaben in water is attributed to the formation of surface plasmonic resonance (SPR) due to the introduction of Ag NPs on the surface of the catalyst. Also, the formation of heterojunction between AgBr and mesoporous‐WO₃ in Ag/AgBr@m‐WO₃ significantly inhibited the recombination of light‐induced electron‐hole pairs in the semiconductor composite. The morphological and optical characterizations of the synthesized photocatalysts (Ag/AgBr@m‐WO₃) were carried out using SEM, TEM, XDR, N₂ adsorption–desorption, UV‐VIS diffuse reflectance spectroscopy (DRS). Also, the photocatalytic studies using radical scavengers were carried out and the results indicated that ${\text{O}}_2^{·-}$ is the main reactive species.