Identification of potential antiviral compounds from Egyptian sea stars against MERS-CoV with the in vitro and in silico experiments

Recently, the world faced many epidemics which were caused by viral respiratory pathogens. Marine creatures including Asteroidea class have been one of the recent research topics due to their diverse and complex secondary metabolites. Some of these constituents exhibit antiviral activities. The present study aimed to extract and identify the potential antiviral compounds from Pentaceraster cumingi, Astropecten polyacanthus and Pentaceraster mammillatus. The results showed that promising activity of the methanolic extract of P. cumingi with 50% inhibitory concentration (IC50) of 3.21 mg/ml against MERS-CoV with a selective index (SI) of 13.975. The biochemical components of the extracts were identified by GC/MS analysis. The Molecular docking study highlighted the virtual mechanism of binding the identified compounds towards three PDB codes of MERS-CoV non-structural protein 10/16. Interestingly, 2-mono Linolein showed promising binding energy of -14.75 Kcal/mol with the second PDB code (5YNI) and -15.22 Kcal/mol with the third PDB code (5YNQ).

Identification of potential antiviral compounds from Egyptian sea stars against seasonal influenza A/H1N1 virus

BACKGROUND

One of the most dangerous problems that the world faced recently is viral respiratory pathogens. Marine creatures, including Echinodermata, specially Asteroidea class (starfish) have been extensively studied due to their miscellaneous bioactivities, excellent pharmacological properties, and complex secondary metabolites, including steroids, steroidal glycosides, anthraquinones, alkaloids, phospholipids, peptides, and fatty acids. These chemical constituents show antiviral activities against a wide range of viruses, including respiratory viruses.

RESULTS

The present study aimed at the identification of potential antiviral compounds from some starfish species. The bioactive compounds from Pentaceraster cumingi, Astropecten polyacanthus, and Pentaceraster mammillatus were extracted using two different solvents (ethyl acetate and methanol). The antiviral activity against influenza A/H1N1 virus showed that ethyl acetate extract from Pentaceraster cumingi has the highest activity, where the selective index was 150.8. The bioactive compounds of this extract were identified by GC/MS analysis. The molecular docking study highlighted the virtual mechanism of binding of the identified compounds towards polymerase basic protein 2 and neuraminidase for H1N1 virus. Interestingly, linoleic acid showed promising binding energy of -10.12 Kcal/mol and -24.20 Kcal/mol for the selected two targets, respectively, and it formed good interactive modes with the key amino acids inside both proteins.

CONCLUSION

The molecular docking analysis showed that linoleic acid was the most active antiviral compound from P. cumingi. Further studies are recommended for in-vitro and in-vivo evaluation of this compound against influenza A/H1N1 virus.

Cytotoxicity and apoptosis induction of the marine Conus flavidus venom in HepG2 cancer cell line

Cancer is still an area of continuous research for finding more effective and selective agents, so our study aimed to explore new anticancer medicines from Cone snails' venoms as marine natural products with promising biological activities. Venoms from seven cone snails collected from two locations on the Red Sea coast (Marsa Alam (Ma) and Hurghada (Hu)) were extracted and subjected to SDS for protein concentrations. The venoms of C. vexillum (Ma), C. vexillum (Hu), and C. flavidus were found to have the highest protein concentrations (2.66, 2.618, and 2.611 mg/mL, respectively). The venom of C. vexillum (Ma) was found to be cytotoxic against the lung cancer cell line A549 (IC50 = 4.511 ± 0.03 µg/mL). On the other hand, the venom of C. flavidus showed a strong cytotoxic effect on both liver and lung cancer cell lines (IC50 = 1.593 ± 0.05 and 7.836 ± 0.4 µg/mL, respectively) when compared to their normal cell lines. Investigating the apoptotic cell death of C. flavidus venom on HepG2 cell lines, it showed total apoptotic cell death by 22.42-fold compared to untreated control and arresting the cell cycle at G2/M phase. Furthermore, its apoptotic cell death in HepG2 cells was confirmed through the upregulation of pro-apoptotic markers and down-regulation of Bcl-2 in both gene and protein expression levels. These findings confirmed the cytotoxic activity of C. flavidus venom through apoptotic cell death in HepG2 cells. So, a detailed study highlighting its structure and molecular target for developing new anticancer agents from natural sources is required.Communicated by Ramaswamy H. Sarma.

Identification of potential antiviral compounds from Egyptian Red Sea soft corals against Middle East respiratory syndrome coronavirus

The ongoing threat of Middle East respiratory syndrome coronavirus (MERS-CoV) underscores the importance of developing effective antiviral treatments. Current research was conducted to identify potential antiviral compounds from soft corals: Sinularia leptoclados, Sarcophyton ehrenbergi, Nephthea sp., Sarcophyton glaucum and Sarcophyton regulare. The antiviral activities of soft corals extracts were evaluated against MERS-CoV. Gas chromatography-mass spectrometry (GC-MS) was used to identify bioactive compounds. The molecular docking was performed to examine the identified compounds for their binding potentials towards three pathogenic factors of MERS-CoV: main protease, spike and non-structural protein 16/10 complex. The methanolic extract of soft coral Sarcophyton regulare exhibited the most promising activity with 50% inhibitory concentration (IC50) of 4.29 µg/ml and selective index (SI) of 112.2. Among the identified compounds in the active fraction, the molecular docking showed that two fatty acid esters: hexadecanoic acid, 2-hydroxy-1-(hydroxymethyl) ethyl ester and octadecanoic acid, 2-hydroxy-1 (hydroxymethyl) ethyl ester had promising docking scores.

Optimization of conditions for decolorization of azo-based textile dyes by multiple fungal species

Wastewater from textile industries contains azo dye residues that negatively affect most environmental systems. The biological treatment of these wastes is the best option due to safety and cost concerns. Here we isolated and identified 19 azo dye-degrading fungi and optimized conditions resulting in enhanced degradation. The fungi belonged to five species of Aspergillus and a single Lichtheimia sp. All fungi were evaluated for their ability to decolorize 20 azo dyes. While the most easily transformable azo dye was direct violet (decolorization ranged from 71.1 to 93.3%), the most resistant to decolorization was fast green azo dye. The greatest degradation potential of azo dyes (direct violet and methyl red) was optimized using the most promising four fungal strains and changing media glucose concentration, nitrogen source, and micronutrients. Biomass, lignin peroxidase, and laccases production were also determined in the optimization studies. The decolorization of both azo dyes by the four fungal strains was greatly enhanced by glucose supplementation. The fungal strains were not able to produce lignin peroxidases in the absence of organic nitrogen source. Both yeast extract and casamino acid supplementation enhanced decolorization of direct violet and methyl red dyes and production of lignin peroxidase by the fungal strains. In contrast, the laccases were absent in the similar medium enriched with the same organic nitrogen sources.

Silybin content and overexpression of chalcone synthase genes in Silybum marianum L. plants under abiotic elicitation

Silymarin, a Silybum marianum seed extract containing a mixture of flavonolignans including silybin, is being used as an antihepatotoxic therapy for liver diseases. In this study, the enhancing effect of gamma irradiation on plant growth parameters of S. marianum under salt stress was investigated. The effect of gamma irradiation, either as a single elicitor or coupled with salinity, on chalcone synthase (CHS) gene expression and silybin A + B yield was also evaluated. The silybin A + B content in S. marianum fruits was estimated by liquid chromatography-mass spectrometry (LC-MS/MS). An increase in silybin content was accompanied by up-regulation of the CHS1, CHS2 and CHS3 genes, which are involved in the silybin biosynthetic pathway. The highest silybin A + B production (0.77 g/100 g plant DW) and transcript levels of the three studied genes (100.2-, 91.9-, and 24.3-fold increase, respectively) were obtained with 100GY gamma irradiation and 4000 ppm salty water. The CHS2 and CHS3 genes were partially sequenced and submitted to the NCBI database under the accession numbers KT252908.1 and KT252909.1, respectively. Developing new approaches to stimulate silybin biosynthetic pathways could be a useful tool to potentiate the use of plants as renewable resources of medicinal compounds.

Identification of a new antifungal oligoacetal derivative produced by Streptomyces toxytricini against Candida albicans

Thirty actinomycete isolates were isolated from soil and tested against Candida albicans in vitro. The active isolate was identified by 16s-rRNA gene sequencing method as Streptomyces toxytricini. The antifungal compound was extracted with ethyl acetate followed by diethyl ether. Both HPLC and GC-MS analysis confirmed presence of one pure compound in the diethyl ether extract. The compound is a yellow liquid has a maximum absorbance at 240 nm in methanol. The chemical structure was elucidated by 1D and 2D-NMR and IR analyses. The elucidated molecular formula was C36H54O14. The compound is a polyacetal tricyclononane derivative, composed of a tricyclononane ring attached from the carbon atom number four with an oligo-acetal chain (six acetal groups in chain) and from the carbon atom number seven with a methoxy carbonyl benzene-1,3-dicarboxylic acid. The purposed name is: 4- {[tricycle(3.2.1.1(1,3))non-8-yl] methoxy carbonyl benzene-1,3-dicarboxylic acid} (2,4,5,6,7,8,9 heptaoxa, 3-ethoxy, 5,6,7,9-tetramethyl unidecane).

Thymoquinone causes multiple effects, including cell death, on dividing plant cells

Thymoquinone (TQ) is a major constituent of Nigella sativa oil with reported anti-oxidative activity and anti-inflammatory activity in animal cells. It also inhibits proliferation and induces programmed cell death (apoptosis) in human skin cancer cells. The present study sought to detect the influence of TQ on dividing cells of three plant systems and on expression of Bcl2-associated athanogene-like (BAG-like) genes that might be involved during the process of cell death. BAG genes are known for the regulation of diverse physiological processes in animals, including apoptosis, tumorigenesis, stress responses, and cell division. Synthetic TQ at 0.1mg/mL greatly reduced wheat seed germination rate, whereas 0.2mg/mL completely inhibited germination. An Evans blue assay revealed moderate cell death in the meristematic zone of Glycine max roots after 1h of TQ treatment (0.2mg/mL), with severe cell death occurring in this zone after 2h of treatment. Light microscopy of TQ-treated (0.2mg/mL) onion hairy root tips for 1h revealed anti-mitotic activity and also cell death-associated changes, including nuclear membrane disruption and nuclear fragmentation. Transmission electron microscopy of TQ-treated cells (0.2mg/mL) for 1h revealed shrinkage of the plasma membrane, leakage of cell lysate, degradation of cell walls, enlargement of vacuoles and condensation of nuclei. Expression of one BAG-like gene, previously associated with cell death, was induced 20 min after TQ treatment in Glycine max root tip cells. Thus, TQ has multiple effects, including cell death, on dividing plant cells and plants may serve as a useful system to further investigate the mechanisms underlying the response of eukaryotic cells to TQ.