In Silico Mining of Terpenes from Red-Sea Invertebrates for SARS-CoV-2 Main Protease (Mpro) Inhibitors.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent for the COVID-19 pandemic, which generated more than 1.82 million deaths in 2020 alone, in addition to 83.8 million infections. Currently, there is no antiviral medication to treat COVID-19. In the search for drug leads, marine-derived metabolites are reported here as prospective SARS-CoV-2 inhibitors. Two hundred and twenty-seven terpene natural products isolated from the biodiverse Red-Sea ecosystem were screened for inhibitor activity against the SARS-CoV-2 main protease (Mpro) using molecular docking and molecular dynamics (MD) simulations combined with molecular mechanics/generalized Born surface area binding energy calculations. On the basis of in silico analyses, six terpenes demonstrated high potency as Mpro inhibitors with ΔGbinding ≤ -40.0 kcal/mol. The stability and binding affinity of the most potent metabolite, erylosides B, were compared to the human immunodeficiency virus protease inhibitor, lopinavir. Erylosides B showed greater binding affinity towards SARS-CoV-2 Mpro than lopinavir over 100 ns with ΔGbinding values of -51.9 vs. -33.6 kcal/mol, respectively. Protein-protein interactions indicate that erylosides B biochemical signaling shares gene components that mediate severe acute respiratory syndrome diseases, including the cytokine- and immune-signaling components BCL2L1, IL2, and PRKC. Pathway enrichment analysis and Boolean network modeling were performed towards a deep dissection and mining of the erylosides B target-function interactions. The current study identifies erylosides B as a promising anti-COVID-19 drug lead that warrants further in vitro and in vivo testing.

Paralemnolins X and Y, New Antimicrobial Sesquiterpenoids from the Soft Coral Paralemnalia thyrsoide.

The organic extracts of the Red Sea soft coral Paralemnalia thyrsoides has led to the identification of two neolemnane-type sesquiterpenoids: paralemnolins X and Y (1, 2). In addition to these newly characterized compounds, ten known metabolites (3-12) were isolated. Previously reported compounds were elucidated by literature comparison of spectroscopic data (1D and 2D NMR as well as MS data). In vitro antimicrobial activity was investigated for compounds (1-12) against Staphylococcus aureus, Escherichia coli, Candida albicans and Aspergillus niger. Compound 5 showed antimicrobial activity against all assayed microorganisms.

Novel eco-friendly amino-modified nanoparticles for phenol removal from aqueous solution.

Herein, the impact of using dried Caulerpa prolifera nanoparticles and silica-coated Caulerpa prolifera nanoparticles for the removal of phenol from aqueous solution has been investigated. The chemical structure and morphology of both dried Caulerpa prolifera nanoparticles and silica-coated Caulerpa prolifera nanoparticles were characterized by using Fourier-transform infrared spectroscopy (FTIR), Brunauer Emmett Teller (BET), scanning electron microscopy (SEM), and transmission electron microscope (TEM). Batch mode experiments were conducted depending on adsorbent dosage, pH, contact time, and initial phenol concentration. In order to investigate the adsorption mechanism of the phenol molecules to the surface of the nanoparticles, kinetic models including pseudo-first-order, pseudo-second-order, and intra-particle diffusion models were executed. To describe the equilibrium isotherms, Langmuir and Freundlich isotherms were analyzed. However, the Langmuir isotherm model was agreed to be more significant with the obtained experimental data.

An insight into fractionation, toxicity, mobility and source apportionment of metals in sediments from El Temsah Lake, Suez Canal.

El Temsah Lake is one of the most important wetlands in the Suez Canal area and the major source of fish for the area. In this study, the relative role of sediments' geochemical properties and metals geochemical fractionation in determining Cd, Cr, Fe, Mn, Ni, and Pb mobility and toxicity was especially concerned. The results reflected that the increasing order of contamination for the investigated metals according to individual contamination factor (ICF) was: Cr > Mn > Ni > Pb > Cd > Fe. Risk assessment code (RAC) classification showed that the relative amounts of easily dissolved phases of metals in the sediments followed the order of Ni > Cr > Cd > Pb > Fe > Mn. The toxicity as indicated by toxic unit (TU) due to an individual metal followed a descending order of Ni > Cr > Pb > Cd, indicating that Ni and Cr accounted for the majority of the overall sediment toxicity while, Cd contributed the least to the ΣTU. This work constitutes a good basis for further studies about metal fractionation in El Temsah Lake which might help policy makers to take effective decisions for proper management of the lake.

Novel chemical sensor for detection Ca(II) ions based on ferutinin.

A new optical chemical sensor based on medicinal compound, jaeschkeanadiol p-hydroxyben-zoate (Ferutinin), has been designed and utilized for Ca(II) ions detections. This natural optical sensor exhibits immense selectivity including fluorescence and absorption ratiometric for Ca(II) ions within precious physiological pH range. Further, the chelation process of the Ca(II) ions with the medicinal optical sensor ferutinin yields a 1:1 (metal: ligand) complex which is accompanied by fluorescence enhancement of the main emission band centered at 355 nm of the medicinal probe. The fluorescence "turn-on" effect is a clear evidence for the chelation process between ferutinin medicinal probe and Ca(II) ions and this could be simply detected. The new sensor was proposed depending on significant fluorescence mechanism, (MLCT, metal-ligand charge transfer). However, the interaction of the medicinal optical sensor with Ca(II) in presence of other cations was examined without any significant interference. Also, the new developed optical sensor consecutively exhibits low limit of detection (LOD) 1.5 nM for Ca(II) which is detected in very significant physiological pH range (pH = 7.4). Also, the probe provides high binding affinity towards Ca(II) with large binding constant Kb 5.97 × 104 M-1. As a result, this optical sensor may apply for detection Ca(II) in cell or biological samples.

New cytotoxic constituents from the Red Sea soft coral Nephthea sp.

Nephthea are soft coral species rich in sesquiterpenoids and steroids. An organic extract of Nephthea sp. resulted in the isolation of a new steroid (1), as well as several previously reported metabolites (2-9). Structures were elucidated by employing NMR and HR-EI-MS analyses. The total extract, fractions and purified compounds exhibited differential cytotoxicity against the breast cancer MCF-7 cell line.

A new steroid from the Red Sea soft coral Lobophytum lobophytum.

Chemical investigation of the soft coral Lobophytum lobophytum collected from the Red Sea led to the isolation of a new compound gorgostan-5,25-dien-3ß-ol (1), and two known compounds gorgosterol (2), and alismol (3). Structures were elucidated by employing extensive NMR and HR-ESI-MS experiments.