Synthesis, spectral characterization, lethal dose (LD50) and acute toxicity studies of 1,4-Bis(imidazolylazo)benzene (BIAB)

Synthesis, characterization, molecular docking and pharmacological evaluation of isoxazole derivatives as potent anti-inflammatory agents

Background

The present study is aimed to investigate the anti-inflammatory activities of thirteen substituted-isoxazole derivatives (5a-5m). Isoxazole is a key pharmacophore in medicinal chemistry, known for its broad range of pharmacological activities.This study explores the synthesis and anti-inflammatory potential of thirteen substituted-isoxazole derivatives (5a-5m), with 5c, 5d, 5e, and 5g being novel compounds.

Objectives

The primary objectives were to synthesize some novel substituted isoxazole derivatives, evaluate their interaction with cyclooxygenase (COX-1/2) enzymes through computational methods, and assess their anti-inflammatory effectiveness in laboratory animals.

Methods

Substituted chalcones (0.01 mol) (2a-2m), sodium ethoxide (0.01 mol), and hydroxylamine hydrochloride (0.01 mol) were dissolved in absolute ethanol (15 ml), and then the mixture was refluxed for 6 h in an oil bath and monitored by TLC (ethyl acetate:hexane 7:3 v/v as eluent; a UV lamp was used to visualize the plates). After the completion of the reaction, as per TLC, the contents of the reaction mixture were poured into ice-cold water (50 ml). The obtained precipitates were filtered, washed two times, dried for 2 h at room temperature, and then recrystallized with ethenol. The structures of these compounds were confirmed via Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance (1H NMR) spectroscopy, carbon-13 nuclear magnetic resonance (13C NMR) spectroscopy, and mass spectrometry. Anti-inflammatory activity was evaluated using the carrageenan-induced rat paw edema method.

Results

The results indicated that three compounds (5b, 5c, and 5d) demonstrated significant in vivo anti-inflammatory potential (% edema inhibition 75.68, 74.48, & 71.86 in 2 h and 76.71, 75.56, & 72.32 in 3 h) with modest effectiveness (0.83, 0.81 & 0.71), low toxicity, and minimal adverse effects. The molecular docking analyses further elucidated the interaction with the active site COX-2 enzyme (PDB ID: 4COX) using Autodock Vina. The compounds 5b, 5c, and 5d -8.7, -8.5, and -8.4 indicate good binding affinity (kcal/mol) and H-bond interaction with residues such as Cys41, Ala151, and Arg120 for COX-2, which also carried out RMSD values of 2.174, 41.13, and 22.25, which are decisive for the reported anti-inflammatory activity of diverse compounds.

Conclusions

The findings indicate that isoxazole derivatives have modest antiinflammatory potential, with compounds (5b, 5c, and 5d) acting as lead molecules to be studied further for pain relief with fewer adverse effects.

Effects of prometryn on oxidative stress, immune response and apoptosis in the hepatopancreas of Eriocheir sinensis (Crustacea: Decapoda)

Prometryn, a triazine pesticide product used to control weed growth, poses a high risk to aquatic organisms in the environment. Several toxicological evaluations have been performed on bony fish and shrimp exposed to prometryn. However, there have been no reports conducted on the toxic mechanism of prometryn with regard to Eriocheir sinensis. In this study, our research evaluated the toxic effects of prometryn via in vitro and in vivo toxicity tests on E. sinensis. Firstly, we estimated the exposure toxicity of prometryn to E. sinensis, and then we constructed a 6 h transcriptional profile and conducted an enrichment analysis. To further reveal the toxicity of prometryn, the hepatopancreas (hepatopancreatic cells) was analyzed for antioxidant, immune and lipid-metabolism-related enzymes, antioxidant- and apoptosis-related gene expression, histopathology and TUNEL. From the results, we determined that the 96 h-LD50 was 70.059 mg/kg, and using RNA-seq, we identified 933 differentially expressed genes (DEGs), which were mainly enriched in the amino and fatty acid metabolism and the cell-fate-determination-related signaling pathway. The results of the biochemical assays showed that prometryn could significantly decrease the activities/levels of CAT, SOD, GSH, AKP and ACP, reduce the levels of T-AOC, TG, TCH, C3 and C4, and increase the MDA content. In addition, the expression levels of Nrf2, GSTs and HO-1 were first upregulated and then downregulated with increasing time. Histopathology showed that prometryn damaged the structure of the hepatopancreas cells and induced apoptosis, suggesting that the PI3K-Akt signaling pathway may be involved in the damage process of hepatopancreas cells (PI3K, PDK and Akt were downregulated whereas Bax was upregulated), leading to their apoptosis. The above results indicated that prometryn could cause injury of the hepatopancreas through oxidative stress, induce cell apoptosis, disrupt the lipid metabolism and cause immune damage. This study provided useful data for understanding and evaluating the toxicity of prometryn to aquatic crustacea.

Enhanced anti-biofilm activity of the minocycline-and-gallium-nitrate using niosome wrapping against Acinetobacter baumannii in C57/BL6 mouse pneumonia model

Acinetobacter baumannii is a worldwide health issue in terms of its high antibiotic resistance and ability to form biofilms. Nanoparticles (NPs) with high biocompatibility, high penetrating ability, and low medication dose can successfully treat the antibiotic-resistant infections. In this research, the anti-biofilm activity of niosomes containing minocycline and gallium nitrate (GaN) against A. baumannii biofilm was determined. In order to improve their anti-biofilm properties, minocycline and GaN were encapsulated in niosomes as biocompatible drug carriers. The niosomes' size, zeta potential, shape, stability, drug entrapment efficacy, drug release pattern and antibacterial activity were assessed. Several clinical samples were isolated from the lungs of patients hospitalized at Loghman hospital, Tehran, Iran. The biofilm formation of most lethal clinical isolates of A. baumannii was analyzed. The pneumonia model was generated by intranasally administering A. baumannii suspension to anesthetized mice whose immune systems was compromised twice by cyclophosphamide. Lung infection of the mouse with A. baumannii was confirmed using PCR. After treatment, the lungs were excised under sterile conditions and stained with hematoxylin and eosin (H&E) to determine histological symptoms, inflammation and intercellular secretions. The niosomes contained minocycline and GaN had an average size of 230 nm and a zeta potential of -40 mV, respectively. The percentage of drug entrapment and delayed drug release was both high in niosomal formulations. Niosomes containing minocycline and GaN dispersed 1, 3 and 5 day old biofilms. The mice given the combination of two compounds required less time to be treated than the animals given the single medication (minocycline). The minocycline& GaN-loaded niosomes could be considered as promising candidates to treat the infections caused by A. baumannii biofilm.