Nanocomposite of gold nanoparticles@nickel disulfide-plant derived carbon for molecularly imprinted electrochemical determination of favipiravir

A molecularly imprinted electrochemical sensor was fabricated for sensitive and selective detection of anti-COVID 19 drug favipiravir (FAV). The sensor is based on the synthesis of biomass-derived carbon (BC) and nickel disulfide nanospheres (NiS2 NS), which were used to decorate glassy carbon electrode (GCE). Then, the gold nanoparticles (AuNPs) were electro- deposited on the surface of NiS2 NS/BC/GCE to enhance conductivity, increase electron transfer, and aid polymerization of p-aminothiophenol (p-ATP) functional monomer. The fabrication steps were characterized using different morphological and electrochemical techniques. Variables affecting the formation of molecularly imprinted layers and the determination of FAV were optimized. Under optimum conditions, the oxidation current (Ipa) was increased upon addition of FAV in the range of 0.42-1100 nM with a limit of detection (LOD, S/N) of 0.13 nM. The as-fabricated sensor possesses several advantages such as high sensitivity and selectivity, good reproducibility, and acceptable stability. Furthermore, the proposed molecularly imprinted –based electrochemical sensor was efficiently applied for the determination of FAV in tablets and human serum samples with recoveries % of 99.2 to 102.1 % and RSDs % in the range of 2.4-3.2 %, which confirms the reliability of the sensor to detect FAV in different matrices.

Targeting 3CLpro and SARS-CoV-2 RdRp by Amphimedon sp. Metabolites: A Computational Study.

Since December 2019, novel coronavirus disease 2019 (COVID-19) pandemic has caused tremendous economic loss and serious health problems worldwide. In this study, we investigated 14 natural compounds isolated from Amphimedon sp. via a molecular docking study, to examine their ability to act as anti-COVID-19 agents. Moreover, the pharmacokinetic properties of the most promising compounds were studied. The docking study showed that virtually screened compounds were effective against the new coronavirus via dual inhibition of SARS-CoV-2 RdRp and the 3CL main protease. In particular, nakinadine B (1), 20-hepacosenoic acid (11) and amphimedoside C (12) were the most promising compounds, as they demonstrated good interactions with the pockets of both enzymes. Based on the analysis of the molecular docking results, compounds 1 and 12 were selected for molecular dynamics simulation studies. Our results showed Amphimedon sp. to be a rich source for anti-COVID-19 metabolites.

Natural metabolites from the soft coral Nephthea sp. as potential SARS-CoV-2 main protease inhibitors.

The ongoing spread of SARS-CoV-2 has created a growing need to develop effective antiviral treatments; therefore, this work was undertaken to delve into the natural metabolites of the Red Sea soft coral Nephthea sp. (family Nephtheidae) as a source of potential anti-COVID-19 agents. Overall, a total of 14 structurally diverse minor constituents were isolated and identified from the petroleum ether fraction of Nephthea sp. The characterised compounds were screened and compared for their inhibitory potential against SARS-CoV-2 main protease (Mpro) using Autodock Vina and MOE software. Interestingly, most compounds were able to bind effectively to the active site of Mpro, of which nephthoside monoacetate (1); an acylated tetraprenyltoluquinol glycoside, exhibited the highest binding capacity in both software with comparable interaction energies to the ligand N3 and moderately acceptable drug-likeness properties, which drew attention to the relevance of marine-derived metabolites from Nephthea sp., particularly compound (1), to develop potential SARS-CoV-2 protease inhibitors.

Potential of (Citrus nobilis Lour × Citrus deliciosa Tenora) metabolites on COVID-19 virus main protease supported by in silico analysis.

One of the promising therapeutic strategies for corona virus 2019 (COVID-19) is tolook for enzyme inhibitors. COVID-19 virus main protease (Mpro) plays a vital role in mediating viral transcription and replication, introducing it as an attractive antiviral agent target. LC-ESI-HDMS based metabolic profiling of Citrus nobilis Lour. × Citrus deliciosa Ten. (Rutaceae) annotated 21 compounds belonging to diverse classes. Molecular docking studies were carried out to ascertain the inhibitory action of studied dereplicated compounds through the interactions within the active site of SARS-CoV-2 (Mpro). Among which, quercetin-7-O-glucoside-3-O-rutinoside (21) possessed the best binding affinity (-9.47 kcal/mol), followed by luteoline-7-rutinoside (18), quercetin-3-O-rutinoside (19) and apigenin-8-C-glucoside (15) showed less binding affinities ranging at -8.27, -7.97 and -6.94 kcal/mol respectively.