Nigrosphaerin A a new isochromene derivative from the endophytic fungus Nigrospora sphaerica

Antimicrobial metabolites produced by endophytic fungi associated with the leaves of Vochysia divergens

Investigation of the endophytic fungi Nigrospora sphaerica, Nigrospora oryzae, and Pseudofusicoccum stromaticum MeOH fractions isolated from the leaves of Vochysia divergens, a medicinal species from the Brazilian Pantanal, led to the identification of five compounds, namely a new compound (1E,8Z)-10,11-dihydroxy-5,5,8-trimethyl-4-oxocycloundeca-1,8-diene-1-carbaldehyde (1) and four known compounds: 5-methylmellein (2), sclerone (3), daldinone A (4), and lasiodiplodin (5). All compounds were identified using spectroscopic methods, and 1 was corroborated with mass spectrometry, while the known compounds were compared with data in the literature. The relative configuration of compound 1 was determined based on theoretical conformational studies as well as the J experimental values between the hydroxymethyne hydrogens. The antimicrobial activity of the compounds was evaluated. Promising results were obtained for compounds 2, 4, and 5 since they inhibited the bacterium Pseudomonas aeruginosa, an opportunistic pathogen, suggesting the potential of these microorganisms as a source of new antibacterial agents.

The chemical constituents of endophytic fungus Nigrospora chinensis of Gannan navel orange

A new drimane sesquiterpene 11-methoxyl-danilol (1) was obtained from endophytic fungus Nigrospora chinensis of Gannan navel orange pulp. Its structure was established to possess a natural rarely-occurring tricyclic acetal fused ring system by means of spectroscopic data analyses. Meanwhile, five known compounds danilol (2), redoxcitrinin (3), euphorbol (4), ergosta-7,24(24')-dien-3β-ol (5), and ergosta-4,6,8(14),22-tetraen-3-one (6) were also co-isolated in this fungus. The results of antibacterial and cytotoxic activity screenings showed that compound 5 displayed antibacterial activities against Staphylococcus aureus and MRSA (methicillin-resistant S. aureus) with MIC value of 50 μg/mL. [Figure: see text].

Cynanotophyllosides E-F, two minor pregnane glycosides from the roots of cultivated Cynanchum otophyllum

Cynanotophyllosides E-F, two new minor pregnane glycosides were isolated from the antidepressant active fraction of cultivated Cynanchum otophyllum, and their structures were determined as 12-O-vanilloyl-deacetylmetaplexigenin 3-O-β -D-glucopyranosyl-(1→4)-β -D-glucopyranosyl-(1→4)-β -D-cymaropyranosyl-(1→4)-β -D-oleandropyranosyl-(1→4)-β -D-digitoxopyranoside, and 12-O-nicotinoyl-deacetylmetaplexigenin 3-O-β -D-glucopyranosyl-(1→4)-β -D-glucopyranosyl-(1→4)-β -D-cymaropyranosyl-(1→4)-β -D-oleandropyranosyl-(1→4)-β -D-cymaropyranoside respectively, with the combination of spectroscopic and chemical analysis.

Endophytes and their potential in biotic stress management and crop production

Biotic stress is caused by harmful microbes that prevent plants from growing normally and also having numerous negative effects on agriculture crops globally. Many biotic factors such as bacteria, fungi, virus, weeds, insects, and nematodes are the major constrains of stress that tends to increase the reactive oxygen species that affect the physiological and molecular functioning of plants and also led to the decrease in crop productivity. Bacterial and fungal endophytes are the solution to overcome the tasks faced with conventional farming, and these are environment friendly microbial commodities that colonize in plant tissues without causing any damage. Endophytes play an important role in host fitness, uptake of nutrients, synthesis of phytohormone and diminish the injury triggered by pathogens via antibiosis, production of lytic enzymes, secondary metabolites, and hormone activation. They are also reported to help plants in coping with biotic stress, improving crops and soil health, respectively. Therefore, usage of endophytes as biofertilizers and biocontrol agent have developed an eco-friendly substitute to destructive chemicals for plant development and also in mitigation of biotic stress. Thus, this review highlighted the potential role of endophytes as biofertilizers, biocontrol agent, and in mitigation of biotic stress for maintenance of plant development and soil health for sustainable agriculture.

Structure-Based Virtual Screening, Docking, ADMET, Molecular Dynamics, and MM-PBSA Calculations for the Discovery of Potential Natural SARS-CoV-2 Helicase Inhibitors from the Traditional Chinese Medicine

Continuing our antecedent work against COVID-19, a set of 5956 compounds of traditional Chinese medicine have been virtually screened for their potential against SARS-CoV-2 helicase (PDB ID: 5RMM). Initially, a fingerprint study with VXG, the ligand of the target enzyme, disclosed the similarity of 187 compounds. Then, a molecular similarity study declared the most similar 40 compounds. Subsequently, molecular docking studies were carried out to examine the binding modes and energies. Then, the most appropriate 26 compounds were subjected to in silico ADMET and toxicity studies to select the most convenient inhibitors to be: (1R,2S)-ephedrine (57), (1R,2S)-norephedrine (59), 2-(4-(pyrrolidin-1-yl)phenyl)acetic acid (84), 1-phenylpropane-1,2-dione (195), 2-methoxycinnamic acid (246), 2-methoxybenzoic acid (364), (R)-2-((R)-5-oxopyrrolidin-3-yl)-2-phenylacetic acid (405), (Z)-6-(3-hydroxy-4-methoxystyryl)-4-methoxy-2H-pyran-2-one (533), 8-chloro-2-(2-phenylethyl)-5,6,7-trihydroxy-5,6,7,8-tetrahydrochromone (637), 3-((1R,2S)-2-(dimethylamino)-1-hydroxypropyl)phenol (818), (R)-2-ethyl-4-(1-hydroxy-2-(methylamino)ethyl)phenol (5159), and (R)-2-((1S,2S,5S)-2-benzyl-5-hydroxy-4-methylcyclohex-3-en-1-yl)propane-1,2-diol (5168). Among the selected 12 compounds, the metabolites, compound 533 showed the best docking scores. Interestingly, the MD simulation studies for compound 533, the one with the highest docking score, over 100 ns showed its correct binding to SARS-CoV-2 helicase with low energy and optimum dynamics. Finally, MM-PBSA studies showed that 533 bonded favorably to SARS-CoV-2 helicase with a free energy value of −83 kJ/mol. Further, the free energy decomposition study determined the essential amino acid residues that contributed favorably to the binding process. The obtained results give a huge hope to find a cure for COVID-19 through further in vitro and in vivo studies for the selected compounds.

A Multistage In Silico Study of Natural Potential Inhibitors Targeting SARS-CoV-2 Main Protease

Among a group of 310 natural antiviral natural metabolites, our team identified three compounds as the most potent natural inhibitors against the SARS-CoV-2 main protease (PDB ID: 5R84), Mpro. The identified compounds are sattazolin and caprolactin A and B. A validated multistage in silico study was conducted using several techniques. First, the molecular structures of the selected metabolites were compared with that of GWS, the co-crystallized ligand of Mpro, in a structural similarity study. The aim of this study was to determine the thirty most similar metabolites (10%) that may bind to the Mpro similar to GWS. Then, molecular docking against Mpro and pharmacophore studies led to the choice of five metabolites that exhibited good binding modes against the Mpro and good fit values against the generated pharmacophore model. Among them, three metabolites were chosen according to ADMET studies. The most promising Mpro inhibitor was determined by toxicity and DFT studies to be caprolactin A (292). Finally, molecular dynamics (MD) simulation studies were performed for caprolactin A to confirm the obtained results and understand the thermodynamic characteristics of the binding. It is hoped that the accomplished results could represent a positive step in the battle against COVID-19 through further in vitro and in vivo studies on the selected compounds.

Secondary metabolites of the genus Nigrospora from terrestrial and marine habitats: Chemical diversity and biological activity

Secondary metabolites produced by the ascomycetes have attracted wide attention from researchers. Their diverse chemical structures and rich biological activities are essential in medicine, food, and agriculture. The monophyletic Nigrospora genus belongs to the Apiosporaceae family and is a rich source of novel and diverse bioactive metabolites. It occurs as a common plant pathogen, endophyte, and saprobe distributed in many ecosystems worldwide. Researchers have focused on discovering new species and secondary metabolites in the past ten years. The host diseases caused by Nigrospora species are also investigated. This review describes 50 references from Web of Science, CNKI, Google Scholar and PubMed related to the secondary metabolites from Nigrospora. Here, a total of 231 compounds isolated from five known species and 21 unidentified species of Nigrospora from January 1991 to June 2022 are summarized. Their structures are attributed to polyketides, terpenoids, steroids, N-containing compounds, and fatty acids. Meanwhile, 77 metabolites exhibited various biological activities like cytotoxic, antifungal, antibacterial, antiviral, antioxidant, anti-inflammatory, antileukemic, antimalarial, phytotoxic, enzyme inhibitory, etc. Notably, this review presents a comprehensive literature survey focusing on the chemistry and bioactivity of secondary metabolites from Nigrospora.

The Computational Preventive Potential of the Rare Flavonoid, Patuletin, Isolated from Tagetes patula, against SARS-CoV-2

The rare flavonoid, patuletin, was isolated from the flowers of Tagetes patula growing in Egypt. The rarity of the isolated compound inspired us to scrutinize its preventive effect against COVID-19 utilizing a multi-step computational approach. Firstly, a structural similarity study was carried out against nine ligands of nine SARS-CoV-2 proteins. The results showed a large structural similarity between patuletin and F86, the ligand of SARS-CoV-2 RNA-dependent RNA polymerase (RdRp). Then, a 3D-Flexible alignment study of patuletin and F86 verified the proposed similarity. To determine the binding opportunity, patuletin was docked against the RdRp showing a correct binding inside its active pocket with an energy of −20 kcal/mol that was comparable to that of F86 (−23 kcal/mol). Following, several MD simulations as well as MM-PBSA studies authenticated the accurate binding of patuletin in the RdRp via the correct dynamic and energetic behaviors over 100 ns. Additionally, in silico ADMET studies showed the general safety and drug-likeness of patuletin.

Hydroanthraquinones from Nigrospora sphaerica and Their Anti-inflammatory Activity Uncovered by Transcriptome Analysis

Transcriptome analysis is shown to be an effective strategy to understand the potential function of natural products. Here, it is reported that 11 previously undescribed hydroanthraquinones [nigroquinones A-K (1-11)], along with eight known congeners, were isolated from Nigrospora sphaerica. Their structures were elucidated by interpreting spectroscopic and spectrometric data including high-resolution mass spectra and nuclear magnetic resonance. The absolute configurations of 1-11 were confirmed by electronic circular dichroism calculations. Transcriptome analysis revealed that 3 (isolated in the largest amount) might be anti-inflammatory. Assays based on LPS-induced RAW264.7 macrophages and zebrafish embryos confirmed that some of the isolated hydroanthraquinones attenuated the secretion of pro-inflammatory mediators in vitro and in vivo. Further Western blotting and immunofluorescence experiments indicated that 4 (which showed the most obvious nitric oxide inhibition) could suppress the expression of nuclear factor-kappa-B (NF-κB), phosphorylation of the inhibitor of NF-κB kinase and inhibit the transportation of NF-κB to the nucleus. Hence, the suppression of the NF-κB signaling pathway may be responsible for the anti-inflammatory effect. These results show that bioactivity evaluation on the basis of transcriptome analysis may be effective in the functional exploration of natural products.

Multi-Step In Silico Discovery of Natural Drugs against COVID-19 Targeting Main Protease

In continuation of our antecedent work against COVID-19, three natural compounds, namely, Luteoside C (130), Kahalalide E (184), and Streptovaricin B (278) were determined as the most promising SARS-CoV-2 main protease (Mpro) inhibitors among 310 naturally originated antiviral compounds. This was performed via a multi-step in silico method. At first, a molecular structure similarity study was done with PRD_002214, the co-crystallized ligand of Mpro (PDB ID: 6LU7), and favored thirty compounds. Subsequently, the fingerprint study performed with respect to PRD_002214 resulted in the election of sixteen compounds (7, 128, 130, 156, 157, 158, 180, 184, 203, 204, 210, 237, 264, 276, 277, and 278). Then, results of molecular docking versus Mpro PDB ID: 6LU7 favored eight compounds (128, 130, 156, 180, 184, 203, 204, and 278) based on their binding affinities. Then, in silico toxicity studies were performed for the promising compounds and revealed that all of them have good toxicity profiles. Finally, molecular dynamic (MD) simulation experiments were carried out for compounds 130, 184, and 278, which exhibited the best binding modes against Mpro. MD tests revealed that luteoside C (130) has the greatest potential to inhibit SARS-CoV-2 main protease.

Isolation and Characterization of Antibacterial Compounds from Aspergillus fumigatus: An Endophytic Fungus from a Mangrove Plant of the Sundarbans

The Sundarbans, a UNESCO world heritage site, is one of the largest mangrove forests in one stretch. Mangrove plants from this forest are little studied for their endophytic fungi. In this study, we isolated fourteen endophytic fungi from the plants Ceriops decandra and Avicennia officinalis collected from the Sundarbans. Five of them were identified as Aspergillus sp. and one as Penicillium sp. by macroscopic and microscopic observation. Antibacterial activity of the crude extracts obtained from these endophytes was determined against Staphylococcus aureus, Micrococcus luteus, Escherichia coli, and Pseudomonas aeruginosa using resazurin-based microtiter assay. The isolated endophytes showed varying degrees of antibacterial activity with MICs ranging between 5 and 0.078 mg/mL. Molecular identification of the most active endophyte revealed its identity as Aspergillus fumigatus obtained from the leaves of C. decandra. Acute toxicity study of the ethyl acetate extract of A. fumigatus in mice revealed no mortality even at the highest dose of 2000 mg/kg bodyweight, though some opposing results are found in the subacute toxicity study. The extract was subjected to silica gel and Sephadex column chromatography resulting in the isolation of three pure compounds. LC-MS analysis of these pure compounds revealed their identity as fumigaclavine C, azaspirofuran B, and fraxetin. This is the first report of fraxetin from A. fumigatus. All three identified compounds were previously reported for their antibacterial activity against different strains of both Gram-positive and Gram-negative bacteria. Therefore, the observed antibacterial activity of the ethyl acetate (EtOAc) extract of A. fumigatus could be due to the presence of these compounds. These results support the notion of investigating fungal endophytes from the Sundarbans for new antimicrobial compounds.

Isolation and In Silico SARS-CoV-2 Main Protease Inhibition Potential of Jusan Coumarin, a New Dicoumarin from Artemisia glauca

A new dicoumarin, jusan coumarin, (1), has been isolated from Artemisia glauca aerial parts. The chemical structure of jusan coumarin was estimated, by 1D, 2D NMR as well as HR-Ms spectroscopic methods, to be 7-hydroxy-6-methoxy-3-[(2-oxo-2H-chromen-6-yl)oxy]-2H-chromen-2-one. As the first time to be introduced in nature, its potential against SARS-CoV-2 has been estimated using various in silico methods. Molecular similarity and fingerprints experiments have been utilized for 1 against nine co-crystallized ligands of COVID-19 vital proteins. The results declared a great similarity between Jusan Coumarin and X77, the ligand of COVID-19 main protease (PDB ID: 6W63), Mpro. To authenticate the obtained outputs, a DFT experiment was achieved to confirm the similarity of X77 and 1. Consequently, 1 was docked against Mpro. The results clarified that 1 bonded in a correct way inside Mpro active site, with a binding energy of -18.45 kcal/mol. Furthermore, the ADMET and toxicity profiles of 1 were evaluated and showed the safety of 1 and its likeness to be a drug. Finally, to confirm the binding and understand the thermodynamic characters between 1 and Mpro, several molecular dynamics (MD) simulations studies have been administered. Additionally, the known coumarin derivative, 7-isopentenyloxycoumarin (2), has been isolated as well as β-sitosterol (3).

Structure and Biological Activity of Ergostane-Type Steroids from Fungi

Mushrooms are known not only for their taste but also for beneficial effects on health attributed to plethora of constituents. All mushrooms belong to the kingdom of fungi, which also includes yeasts and molds. Each year, hundreds of new metabolites of the main fungal sterol, ergosterol, are isolated from fungal sources. As a rule, further testing is carried out for their biological effects, and many of the isolated compounds exhibit one or another activity. This study aims to review recent literature (mainly over the past 10 years, selected older works are discussed for consistency purposes) on the structures and bioactivities of fungal metabolites of ergosterol. The review is not exhaustive in its coverage of structures found in fungi. Rather, it focuses solely on discussing compounds that have shown some biological activity with potential pharmacological utility.

Jusanin, a New Flavonoid from Artemisia commutata with an In Silico Inhibitory Potential against the SARS-CoV-2 Main Protease

A new flavonoid, Jusanin, (1) has been isolated from the aerial parts of Artemisia commutata. The chemical structure of Jusanin has been elucidated using 1D, 2D NMR, and HR-Ms spectroscopic methods to be 5,2',4'-trihydroxy-6,7,5'-trimethoxyflavone. Being new in nature, the inhibition potential of 1 has been estimated against SARS-CoV-2 using different in silico techniques. Firstly, molecular similarity and fingerprint studies have been conducted for Jusanin against co-crystallized ligands of eight different SARS-CoV-2 essential proteins. The studies indicated the similarity between 1 and X77, the co-crystallized ligand SARS-CoV-2 main protease (PDB ID: 6W63). To confirm the obtained results, a DFT study was carried out and indicated the similarity of (total energy, HOMO, LUMO, gap energy, and dipole moment) between 1 and X77. Accordingly, molecular docking studies of 1 against the target enzyme have been achieved and showed that 1 bonded correctly in the protein's active site with a binding energy of -19.54 Kcal/mol. Additionally, in silico ADMET in addition to the toxicity evaluation of Jusanin against seven models have been preceded and indicated the general safety and the likeness of Jusanin to be a drug. Finally, molecular dynamics simulation studies were applied to investigate the dynamic behavior of the Mpro-Jusanin complex and confirmed the correct binding at 100 ns. In addition to 1, three other metabolites have been isolated and identified to be сapillartemisin A (2), methyl-3-[S-hydroxyprenyl]-cumarate (3), and β-sitosterol (4).

Isolation and In Silico Anti-SARS-CoV-2 Papain-like Protease Potentialities of Two Rare 2-Phenoxychromone Derivatives from Artemisia spp

Two rare 2-phenoxychromone derivatives, 6-demethoxy-4`-O-capillarsine (1) and tenuflorin C (2), were isolated from the areal parts of Artemisia commutata and A. glauca, respectively, for the first time. Being rare in nature, the inhibition potentialities of 1 and 2 against SARS-CoV-2 was investigated using multistage in silico techniques. At first, molecular similarity and fingerprint studies were conducted for 1 and 2 against co-crystallized ligands of eight different COVID-19 enzymes. The carried-out studies indicated the similarity of 1 and 2 with TTT, the co-crystallized ligand of COVID-19 Papain-Like Protease (PLP), (PDB ID: 3E9S). Therefore, molecular docking studies of 1 and 2 against the PLP were carried out and revealed correct binding inside the active site exhibiting binding energies of −18.86 and −18.37 Kcal/mol, respectively. Further, in silico ADMET in addition to toxicity evaluation of 1 and 2 against seven models indicated the general safety and the likeness of 1 and 2 to be drugs. Lastly, to authenticate the binding and to investigate the thermodynamic characters, molecular dynamics (MD) simulation studies were conducted on 1 and PLP.

In Silico Screening of Semi-Synthesized Compounds as Potential Inhibitors for SARS-CoV-2 Papain-like Protease: Pharmacophoric Features, Molecular Docking, ADMET, Toxicity and DFT Studies

Papain-like protease is an essential enzyme in the proteolytic processing required for the replication of SARS-CoV-2. Accordingly, such an enzyme is an important target for the development of anti-SARS-CoV-2 agents which may reduce the mortality associated with outbreaks of SARS-CoV-2. A set of 69 semi-synthesized molecules that exhibited the structural features of SARS-CoV-2 papain-like protease inhibitors (PLPI) were docked against the coronavirus papain-like protease (PLpro) enzyme (PDB ID: (4OW0). Docking studies showed that derivatives 34 and 58 were better than the co-crystallized ligand while derivatives 17, 28, 31, 40, 41, 43, 47, 54, and 65 exhibited good binding modes and binding free energies. The pharmacokinetic profiling study was conducted according to the four principles of the Lipinski rules and excluded derivative 31. Furthermore, ADMET and toxicity studies showed that derivatives 28, 34, and 47 have the potential to be drugs and have been demonstrated as safe when assessed via seven toxicity models. Finally, comparing the molecular orbital energies and the molecular electrostatic potential maps of 28, 34, and 47 against the co-crystallized ligand in a DFT study indicated that 28 is the most promising candidate to interact with the target receptor (PLpro).

In Silico Exploration of Potential Natural Inhibitors against SARS-Cov-2 nsp10

In continuation of our previous effort, different in silico selection methods were applied to 310 naturally isolated metabolites that exhibited antiviral potentialities before. The applied selection methods aimed to pick the most relevant inhibitor of SARS-CoV-2 nsp10. At first, a structural similarity study against the co-crystallized ligand, S-Adenosyl Methionine (SAM), of SARS-CoV-2 nonstructural protein (nsp10) (PDB ID: 6W4H) was carried out. The similarity analysis culled 30 candidates. Secondly, a fingerprint study against SAM preferred compounds 44, 48, 85, 102, 105, 182, 220, 221, 282, 284, 285, 301, and 302. The docking studies picked 48, 182, 220, 221, and 284. While the ADMET analysis expected the likeness of the five candidates to be drugs, the toxicity study preferred compounds 48 and 182. Finally, a density-functional theory (DFT) study suggested vidarabine (182) to be the most relevant SARS-Cov-2 nsp10 inhibitor.

Traditional ancient Egyptian medicine: A review

The ancient Egyptians practiced medicine with highly professional methods. They had advanced knowledge of anatomy and surgery. Also, they treated a lot of diseases including dental, gynecological, gastrointestinal, and urinary disorders. They could diagnose diabetes and cancer. The used therapeutics extended from different plants to include several animal products and minerals. Some of these plants are still used in the present day. Fortunately, they documented their life details by carving on stone, clay, or papyri. Although a lot of these records have been lost or destroyed, the surviving documents represent a huge source of knowledge in different scientific aspects including medicine. This review article is an attempt to understand some information about traditional medicine in ancient Egypt, we will look closely at some basics, sources of information of Egyptian medicine in addition to common treated diseases and therapeutics in this great civilization.

Isolation, Crystal Structure, and In Silico Aromatase Inhibition Activity of Ergosta-5, 22-dien-3β-ol from the Fungus Gyromitra esculenta

Ergosterol derivatives exhibited copious promising biological activities. The fungus Gyromitra esculenta is widely distributed in Europe and North America. In order to examine the chemical properties of Gyromitra esculenta, a phytochemical study has been preceded and resulted in the isolation of the steroid, ergosta-5, 22-dien-3β-ol (brassicasterol), from its methanol extract. The complete identification and absolute configuration of the isolated compound have been established by X-ray structural analysis to be (22E, 24R)-24-methylcholesta-5, 22-dien-3beta-ol. The reported cytotoxicity and the great structural similarity of the isolated compound with the cocrystallized ligand of the aromatase enzyme inspired us to run molecular docking studies against that protein. Ergosta-5, 22-dien-3β-ol occupied the target protein with a binding mode almost the same as the cocrystallized ligand and a binding affinity of −33.55 kcal/mol, which was better than that of the cocrystallized ligand (−22.61 kcal/mol). This promising result encouraged us to conduct in silico ADMET and toxicity studies of ergosta-5, 22-dien-3β-ol against 6 models, and the results expected the likeness of the isolated compound to be a drug. In conclusion, ergosta-5, 22-dien-3β-ol has been isolated from Gyromitra esculenta, identified by X-ray structural analysis, and exhibited promising in silico activities against aromatase enzyme.

Comprehensive In Silico Screening of the Antiviral Potentialities of a New Humulene Glucoside from Asteriscus hierochunticus against SARS-CoV-2

Chromatographic fractionation of the methanolic extract of Asteriscus hierochunticus whole plant led to the identification of a new humulene glucoside (1). The chemical structure of the isolated compound was elucidated by IR, 1D, 2D NMR, and HRESIMS data analysis to be (-)-(2Z,6E,9E)8α-hydroxy-2,6,9-humulatrien-1(12)-olide. In this study, we report the in silico binding affinities of 1 against four different SARS-CoV-2 proteins (COVID-19 main protease (PDB ID: 6lu7), nonstructural protein (PDB ID: 6W4H), RNA-dependent RNA polymerase (PDB ID: 7BV2), and SARS-CoV-2 helicase (PDB ID: 5RMM)). The isolated compound showed excellent binding affinity values (ΔG) of −21.65, −20.05, −28.93, and −21.73 kcal/mol, respectively, against the target proteins compared to the cocrystallized ligands that exhibited ΔG values of −23.75, −17.65, −23.57, and −15.30 kcal/mol, respectively. Further in silico investigations of the isolated compound (1) for its ADMET and toxicity profiles revealed excellent drug likeliness. On the other hand, the results obtained from in vitro antitrypanosomal, antileishmanial, and antimalarial activities of (1) were not promising.

Molecular characterization of a novel partitivirus and a fusarivirus coinfecting the fungus Nigrospora sphaerica

In this report, we describe the molecular characterization of two novel mycoviruses coinfecting the plant pathogenic fungus Nigrospora sphaerica, which were designated "Nigrospora sphaerica fusarivirus 1" (NsFV1) and "Nigrospora sphaerica partitivirus 1" (NsPV1). NsFV1 has an undivided genome measuring 6,147 nt, excluding the polyA tail, and was predicted to contain two nonoverlapping open reading frames (ORF1 and 2). The larger ORF1 encodes a polyprotein containing a conserved RNA-dependent RNA polymerase (RdRp) and a helicase domain that has functions related to RNA replication, and the smaller ORF2 encodes a putative protein with an unknown function. NsPV1 consists of two genome segments, which measure 1,796 bp and 1,455 bp in length. Each of the two dsRNAs has a single ORF, and they are predicted to encode proteins with homology to viral RdRps and coat proteins of members of the family Partitiviridae. Phylogenetic analysis indicated that NsFV1 is a member of the recently proposed family "Fusariviridae", while NsPV1 was determined to belong to the genus Gammapartitivirus in the family Partitiviridae. To the best of our knowledge, this report is the first to describe mycoviruses infecting N. sphaerica.

Isolation and In Silico Anti-COVID-19 Main Protease (Mpro) Activities of Flavonoids and a Sesquiterpene Lactone from Artemisia sublessingiana

The emergence of the COVID-19 pandemic declared the huge need of humanity for new and effective antiviral drugs. The reported antimicrobial activities of Artemisia sublessingiana encouraged us to investigate the ethanol extract of its aerial parts which led to the isolation of six flavonoids and a sesquiterpenoid. The structures of the isolated compounds were elucidated by EI-MS, 1D, and 2D NMR spectroscopic methods to be (1) eupatilin, (2) 3′,4′-dimethoxyluteolin, (3) 5,7,3′-trihydroxy-6,4′,5′-trimethoxyflavone, (4) hispidulin, (5) apigenin, (6) velutin, and (7) sesquiterpene lactone 8α,14-dihydroxy-11,13-dihydromelampolide. The isolated compounds were in silico examined against the COVID-19 main protease (Mpro) enzyme. Compounds 1–6 exhibited promising binding modes showing free energies ranging from −6.39 to −6.81 (kcal/mol). The best binding energy was for compound 2. The obtained results give hope of finding a treatment for the COVID-19 pandemic.

Eissa I, Metwaly AM. In Silico Studies of Some Isoflavonoids as Potential Candidates against COVID-19 Targeting Human ACE2 (hACE2) and Viral Main Protease (Mpro)

The Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused the "COVID-19" disease that has been declared by WHO as a global emergency. The pandemic, which emerged in China and widespread all over the world, has no specific treatment till now. The reported antiviral activities of isoflavonoids encouraged us to find out its in silico anti-SARS-CoV-2 activity. In this work, molecular docking studies were carried out to investigate the interaction of fifty-nine isoflavonoids against hACE2 and viral Mpro. Several other in silico studies including physicochemical properties, ADMET and toxicity have been preceded. The results revealed that the examined isoflavonoids bound perfectly the hACE-2 with free binding energies ranging from -24.02 to -39.33 kcal mol-1, compared to the co-crystallized ligand (-21.39 kcal mol-1). Furthermore, such compounds bound the Mpro with unique binding modes showing free binding energies ranging from -32.19 to -50.79 kcal mol-1, comparing to the co-crystallized ligand (binding energy = -62.84 kcal mol-1). Compounds 33 and 56 showed the most acceptable affinities against hACE2. Compounds 30 and 53 showed the best docking results against Mpro. In silico ADMET studies suggest that most compounds possess drug-likeness properties.

Synthesis and Molecular Docking of Some Grossgemin Amino Derivatives as Tubulin Inhibitors Targeting Colchicine Binding Site

Six amino derivatives of grossgemin (2–7) were synthesized according to the reported essential pharmacophoric features of colchicine binding site inhibitors (CBSIs). The derivatives 4–6 were obtained for the first time. The pharmacophoric features of 2–7 as CBSIs were studied to be almost identical. Furthermore, the 3D-flexible alignment of compound 5 as a representative example with colchicine showed a very good overlapping. In agreement, compounds 2–7 docked into CBS with binding modes very similar to that of colchicine and exhibited binding free energies of −24.57, −25.05, −32.16, −29.34, −26.38, and −26.86 (kcal/mol), respectively. The binding free energies of 4–7 were better than that of colchicine (−26.13 kcal/mol) with a noticeable superiority to compound 4.

In Vitro and In Silico Cytotoxic and Antibacterial Activities of a Diterpene from Cousinia alata Schrenk

A biologically guided isolation of secondary metabolites from Cousinia alata Schrenk wild plant growing in Akmola region, Kazakhstan, led to the isolation of the bioactive diterpene grindelic acid (1). Six flavonoids were also isolated and identified as retusine (2), pachipodol (3), jaranol (4), penduletin (5), casticin (6), and 5, 7, 3′-trihydroxy-3, 4′-dimethoxyflavone (7). Penduletin (5) showed moderate cytotoxic activity assay. Grindelic acid exhibited promising cytotoxic activity against the Artemia salina nauplii and antibacterial activity against Staphylococcus aureus, Bacillus cereus, and Salmonella enteritidis. The presence of the essential pharmacophoric features of histone deacetylase (HDAC) inhibitors in the structure of grindelic acid encouraged us to run a molecular docking study against the HDAC enzyme to understand its mechanism of action on a molecular level. Grindelic acid showed a binding mode of interaction similar to that of the cocrystallized ligand and exhibited good binding affinity against HDAC with the binding free energy of −18.70 kcal/mol. The structures of isolated compounds were determined by MS, 1D, and 2D NMR spectroscopy methods. Compounds (1–7) were isolated for the first time from Cousinia genus.

Nigrospora Species Associated with Various Hosts from Shandong Peninsula, China

Nigrospora is a monophyletic genus belonging to Apiosporaceae. Species in this genus are phytopathogenic, endophytic, and saprobic on different hosts. In this study, leaf specimens with disease symptoms were collected from host plants from the Shandong Peninsula, China. The fungal taxa associated with these leaf spots were studied using morphology and phylogeny based on ITS, TEF1, and TUB2 gene regions. In this article, we report on the genus Nigrospora with N. gorlenkoana, N. oryzae, N. osmanthi, N. rubi, and N. sphaerica identified with 13 novel host associations including crops with economic importance such as bamboo and Chinese rose.

Characterization and evaluation of mycosterol secreted from endophytic strain of Gymnema sylvestre for inhibition of α-glucosidase activity

Endophytic fungi produce various types of chemicals for establishment of niche within the host plant. Due to symbiotic association, they secrete pharmaceutically important bioactive compounds and enzyme inhibitors. In this research article, we have explored the potent α-glucosidse inhibitor (AGI) produced from Fusarium equiseti recovered from the leaf of Gymnema sylvestre through bioassay-guided fraction. This study investigated the biodiversity, phylogeny, antioxidant activity and α-glucosidse inhibition of endophytic fungi isolated from Gymnema sylvestre. A total of 32 isolates obtained were grouped into 16 genera, according to their morphology of colony and spores. A high biodiversity of endophytic fungi were observed in G. sylvestre with diversity indices. Endophytic fungal strain Fusarium equiseti was identified through DNA sequencing and the sequence was deposited in GenBank database (https://ncbi.nim.nih.gov) with acession number: MF403109. The characterization of potent compound was done by FTIR, LC-ESI-MS and NMR spectroscopic analysis with IUPAC name 17-(5-ethyl-6-methylheptan-2-yl)-10,13-dimethyl-2,3,4,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta[a] phenanthren-3-ol. The isolated bioactive compound showed significant α-amylase and α-glucosidase inhibition activity with IC50 values, 4.22 ± 0.0005 µg/mL and 69.72 ± 0.001 µg/mL while IC50 values of acarbose was 5.75 ± 0.007 and 55.29 ± 0.0005 µg/mL respectively. This result is higher in comparison to other previous study. The enzyme kinetics study revealed that bioactive compound was competitive inhibitor for α-amylase and α-glucosidase. In-silico study showed that bioactive compound binds to the binding site of α-amylase, similar to that of acarbose but with higher affinity. The study highlights the importance of endophytic fungi as an alternative source of AGI (α-glucosidase inhibition) to control the diabetic condition in vitro.

Evaluation of in vitro alpha-glucosidase inhibitory, antimicrobial, and cytotoxic activities of secondary metabolites from the endophytic fungus, Nigrospora sphaerica, isolated from Helianthus annuus

Purpose

This study aimed to evaluate alpha-glucosidase inhibition and antimicrobial activity as well as cytotoxic activity of extracts from the endophytic fungus, Nigrospora sp., isolated from leaves of Helianthus annuus, which is widely cultivated for food and used as a medicinal plant.

Methods

The fungus (TSU-CS003) was identified based on internal transcribed spacer ribosomal DNA sequences and fungal biomass, and fermentation broth was subjected to extraction by solvents (hexane and ethyl acetate). All extracts were tested for their antimicrobial activity, alpha-glucosidase inhibition, and cytotoxicity activity. In addition, the active extract was analyzed by using gas chromatography mass spectrometry (GC-MS)

Results

TSU-CS003 was identified as Nigrospora sphaerica. The fermentation broth extract (BE) showed strong antimicrobial activity against Staphylococcus aureus and methicillin-resistant S. aureus (Gram-positive bacteria) with minimum inhibitory concentration (MIC) values in the range of 16–32 μg/mL and a few yeasts with MIC values ranging from 64 to 128 μg/mL, especially Talaromyces marneffei with an MIC value of 4 μg/mL. The effects of BE were observed by SEM. The results showed that this extract affected the cell morphology of T. marneffei. The half-maximal inhibitory concentration (IC50) of BE from alpha-glucosidase inhibition was recorded as 17.25 μg/mL and also showed significant cytotoxicity against A549 human cancer cell lines with an IC50 value of 22.41 μg/mL. Furthermore, BE was analyzed by using GC-MS and divided into three main compounds, including 5-pentyldihydrofuran-2(3H)-one, (Z)-methyl 4-(isobutyryloxy)but-3-enoate, and 2-phenylacetic acid.

Conclusion

This was the first report of the endophytic fungus N. sphaerica from H. annuus. It is a potential source of active metabolites, which gave the strong antifungal activity, antioxidant activity, and cytotoxicity to A549 cancer cell lines.

Anti-leishmanial and Anti-inflammatory Agents from Endophytes: A Review

Leishmaniases and chronic inflammatory diseases are the cause of millions of deaths in the world each year. The treatment of leishmaniasis is facing serious drawbacks particularly due to the limited number of effective medicines, the resistance, and the toxicity of available drugs. On the other hand, many drugs are used for the management of inflammatory disorders. However, the most commonly prescribed although efficient is highly toxic with multiples side effects. New leads compounds for the development of new anti-leishmanial and anti-inflammatory drugs are needed. Over the past decade, several studies on the potential of endophytes to produce bioactive metabolites have been reported. We are presenting in the present review the status of research from 2000 to 2019 on the anti-leishmanial and anti-inflammatory metabolites isolated from endophytes from diverse habitats. An emphasis was put on existing gaps in the literature to inspire and guide future investigations. We hope that this review will help accelerate the drug discovery against leishmaniases and inflammation-associated disorders.

Isolation and structure determination of a new indene derivative from endophytic fungus Aspergillus flavipes Y-62

As part of the search for naturally derived secondary metabolites, a novel indene derivative, compound 1, together with nine known metabolites (2-10) have been purified from an ethyl acetate extract of the plant-associated fungus Aspergillus flavipes Y-62, isolated from Suaeda glauca (Bunge) Bunge which was collected along Zhoushan coast, Zhejiang province, East China. The structure of the new compound 1 was elucidated by extensive use of spectroscopic techniques like 1D, 2D NMR, and HR-TOF-MS, while the known metabolites were established based on both spectral methods as well as by comparison with the previous literature. Compound 1 exhibited antimicrobial activities against the gram-negative pathogen Pseudomonas aeruginosa and Klebsiella pneumoniae with equal MIC values of 32 µg/ml.

Secrets of plants: Endophytes

Endophytic fungi are an important component that colonizes in healthy tissues of living plants and can be readily isolated from any microbial or plant growth medium. They act as reservoirs of novel bioactive secondary metabolites, such as alkaloids, phenolic acids, quinones, steroids, saponins, tannins, and terpenoids that serve as a potential candidate for antimicrobial, anti-insect, anticancer and many more properties. Their huge diversity and particular habituation, they can provide a good area for research in the field of making new medicines and novel drug-like molecules. Because of the impact of endophytes on host plant by enhancing their growth or increasing their fitness, also making them tolerant to abiotic and biotic stresses and holding the secondary metabolites, endophytes are gaining attention as a subject for research. This review aims to comprehend the contribution and uses of endophytes and relationships between endophytic fungi and their host medicinal plants.

Microbial Sterolomics as a Chemical Biology Tool

Metabolomics has become a powerful tool in chemical biology. Profiling the human sterolome has resulted in the discovery of noncanonical sterols, including oxysterols and meiosis-activating sterols. They are important to immune responses and development, and have been reviewed extensively. The triterpenoid metabolite fusidic acid has developed clinical relevance, and many steroidal metabolites from microbial sources possess varying bioactivities. Beyond the prospect of pharmacognostical agents, the profiling of minor metabolites can provide insight into an organism's biosynthesis and phylogeny, as well as inform drug discovery about infectious diseases. This review aims to highlight recent discoveries from detailed sterolomic profiling in microorganisms and their phylogenic and pharmacological implications.

Terezine E, bioactive prenylated tryptophan analogue from an endophyte of Centaurea stoebe

Fungal endophytes are considered promising sources of new bioactive natural products. In this study, a Mucor sp. has been isolated as an endophyte from the medicinal plant Centaurea stoebe. Through bioactivity-guided fractionation, the isolation of the new bioactive terezine E in addition to the previously reported 14-hydroxyterezine D was carried out. The isolated compounds were fully characterised by HRESIMS and 1D and 2D NMR analyses. Both compounds exhibited potent antiproliferative activity against K-562 and HUVEC cell lines and antifungal efficacy against the tested fungal strains.

New Antimicrobial Cyclopentenones from Nigrospora sphaerica ZMT05, a Fungus Derived from Oxya chinensis Thunber

Six new cyclopentenone derivatives (+)-nigrosporione A (+)-1, (-)-nigrosporione A (-)-1, nigrosporione B (2), nigrosporione C (3), (+)-nigrosporione D (+)-4, and (-)-nigrosporione D (-)-4 were isolated from an endophytic fungus Nigrospora sphaerica ZMT05, collected from the rice grasshopper ( Oxya chinensis Thunberg), which is an insect pest in rice and which is also used as a food for people in some countries. Their planar and spatial structures were determined by spectroscopic analyses and eletronic circular dichroism (ECD) calculations. Compounds (+)-1, (-)-1, and 2 inhibited the plant pathogens Fusarium oxysporum, Colletotrichum musae, Penicillium italicum, and Fusarium graminearum, compounds 3 and (-)-4 inhibited F. oxysporum, C. musae, and P. italicum, and compound (+)-4 inhibited F. oxysporum, C. musae, and F. graminearum, showing antifungal activities stronger than triadimefon. Additionally, compounds (+)-1, (-)-1, 2, and 3 displayed moderate antibacterial activities against Staphyloccocus aureus and Escherichia coli.

Two new compounds from Nigrospora sphaerica ZMT05, a fungus derivated from Oxya chinensis Thunber

A new pyrrolidinone derivative named nigrosporamide A (1), and a new acetophenone derivative, 4-prenyloxyclavatol (2), were isolated from an endophytic fungus Nigrospora sphaerica (collection No. ZMT05) isolated from Oxya chinensis Thunberg. Their chemical structures were established on the basis of the interpretation of spectroscopic data. In primary in vitro bioassay, nigrosporamide A (1) exhibited strong antifungal activity against Colletotrichum gloeosporioides and high inhibitory activity towards α-glucosidase.

Evaluation of bioactive secondary metabolites from endophytic fungus Pestalotiopsis neglecta BAB-5510 isolated from leaves of Cupressus torulosa D.Don

Six endophytic fungi were isolated from Cupressus torulosa D.Don and identified phenotypically and genotypically. The fungal cultures were further grown and the culture was extracted by two organic solvents methanol and ethyl acetate. The screening was carried out using the agar well diffusion method against human pathogen such as Escherichia coli, Salmonella typhimurium, Bacillus subtilis and Staphylococcus aureus. Isolated strain of Pestalotiopsis sp. was showing prominent antibacterial activity. The crude methanol and ethyl acetate extract of Pestalotiopsis sp. showed MIC of 6.25 mg/mL for S. typhimurium and S. aureus which showed its efficacy as a potent antimicrobial. The phytochemical screening revealed the existence of a diverse group of secondary metabolites in the crude extracts of the endophytic fungi that resembled those in the host plant extracts. On the basis of phenotypic characteristics and rDNA sequencing of the ITS region of the endophyte was identified as P. neglecta which turned out to be a promising source of bioactive compounds. There is little known about endophytes from C. torulosa D.Don. In this paper we studied in detail the identification of isolated endophytic fungi P. neglecta from C. torulosa D.Don and characterization of its active metabolite compounds. The partially purified second fraction (PPF) extracted from the fungal culture supernatant was subjected to gas chromatography followed by mass spectrometry which revealed the presence of many phytochemicals. These results indicate that endophytic fungi P. neglecta isolated from medicinal plants could be a potential source for bioactive compounds and may find potential use in pharmaceutical industry.

Antibacterial activity of endophytic fungi from leaves of Indigofera suffruticosa Miller (Fabaceae)

Endophytic fungi were isolated from healthy leaves of Indigofera suffruticosa Miller, a medicinal plant found in Brazil which is used in folk medicine to treat various diseases. Among 65 endophytic fungi isolated, 18 fungi showed activity against at least one tested microorganism in preliminary screening, and the best results were obtained with Nigrospora sphaerica (URM-6060) and Pestalotiopsis maculans (URM-6061). After fermentation in liquid media and in semisolid media, only N. sphaerica demonstrated antibacterial activity (in Potato Dextrose Broth-PDB and in semisolid rice culture medium). In the next step, a methanolic extract from rice culture medium (NsME) and an ethyl acetate extract (NsEAE) from the supernatant of PDB were prepared and both exhibited antimicrobial activity against Gram-negative and Gram-positive bacteria. The best result was observed against Staphylococcus aureus, with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 1.56 mg/mL and 6.25 mg/mL, respectively, for NsME and MIC and MBC values of 0.39 mg/mL and 3.12 mg/mL, respectively, for NsEAE. This study is the first report about the antimicrobial activity of endophytic fungi residing in I. suffruticosa leaves, in which the fungus N. sphaerica demonstrated the ability to produce bioactive agents with pharmaceutical potential, and may provide a new lead in the pursuit of new biological sources of drug candidates.