Metal nanoparticle (MNP)-catalyzed synthesis of nitrogen- and oxygen-containing heterocyclic scaffolds.

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Among the several heterocyclic compounds, nitrogen and oxygen are predominant heterocycles due to their abundant biological importance. The nanoparticles have demonstrated the excellent catalytic activity under optimum conditions with higher reusability or recyclability and higher yields of synthetic heterocyclic targets. Previously we reviewed the synthesis of aza- and oxa-heterocycles catalyzed by metal nanoparticles (MNPs) in 2009-2019 and published an update of such reports of 2020 on the same subject. With anticipations to the next, the present comprehensive work highlights the synthesis of aza- and oxa-heterocycles catalyzed by MNPs reported during the year, 2021 to update the reader of the present work with the most recent trends in selection of MNPs in the synthesis of desired heterocyclic scaffolds.

The immune system plays a significant role in the development, invasion, progression, and metastasis of head and neck cancer. Over the last decade, the emergence of immunotherapy has irreversibly altered the paradigm of cancer treatment. The current treatment modalities for head and neck squamous cell carcinoma (HNSCC) include surgery, radiotherapy, and adjuvant or neoadjuvant chemotherapy which has failed to provide satisfactory clinical outcomes. To encounter this, there is a need for a novel or targeted therapy such as immunological targets along with conventional treatment strategy for optimal therapeutic outcomes. The immune system can contribute to promoting metastasis, angiogenesis, and growth by exploiting the tumor's influence on the microenvironment. Immunological targets have been found effective in recent clinical studies and have shown promising results. This review outlines the important immunological targets and the medications acting on them that have already been explored, are currently under clinical trials and are further being targeted.

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Dabigatran etexilate mesylate is an anticoagulant drug. Dabigatran demonstrated its efficacy for prophylaxis and treatment of thromboembolic event during orthopaedic surgery and curative treatment of hypercoagulability in atrial fibrillation. The present study deals with the development and validation of a stability-indicating high performance thinlayer chromatography (HPTLC) method for the estimation of Dabigatran etexilate mesylate using TLC plates precoated with silica gel 60 F254 as stationary phase and toluene: ethyl acetate: methanol: formic acid (3:4:3:0.2, v/v/v/v) as the mobile phase. The drug was subjected to stress conditions such as hydrolysis, oxidation, photolysis, neutral and dry heat. Degradation products produced as a result of the stress conditions did not interfere with the detection of DEM, therefore the proposed method can be considered stabilityindicating. DEM showed degradation under hydrolytic, oxidative, photolytic and dry heat conditions. DEM (Rf 0.47 ± 0.02) and its degradation products were well resolved. The wavelength selected for quantitation was 314 nm. The method was linear in the concentration range 50-250 ng/spot with a correlation coefficient of 0.9955. The %RSD for repeatability of peak area measurement was found to be 0.62 and %RSD for repeatability of sample application was found to be 0.75. The % RSD of intraday and interday precisions were 0.91-1.5 and 1.21-1.7 respectively. The accuracy (recovery) was found to be in the range of 99.45-100.37 %. The developed method was applied for assay of marketed formulations and the results were found to be good agreement with labelled claim of formulations.

Due to alarming outbreak of pandemic COVID‐19 in recent times, there is a strong need to discover and identify new antiviral agents acting against SARS CoV‐2. Among natural products, lignan derivatives have been found effective against several viral strains including SARS CoV‐2. Total of twenty‐seven reported antiviral lignan derivatives of plant origin have been selected for computational studies to identify the potent inhibitors of SARS CoV‐2. Molecular docking study has been carried out in order to predict and describe molecular interaction between active site of enzyme and lignan derivatives. Out of identified hits, clemastatin B and erythro‐strebluslignanol G demonstrated stronger binding and high affinity with all selected proteins. Molecular dynamics simulation studies of clemastin B and savinin against promising targets of SARS CoV‐2 have revealed their inhibitory potential against SARS CoV‐2. In fine, in‐silico computational studies have provided initial breakthrough in design and discovery of potential SARS CoV‐2 inhibitors.