Publications by authors named "Weaam Ebrahim"

Dysregulation of the Wnt signaling pathway contributes to the development of many cancer types. Natural compounds produced with biotechnological systems have been the focus of research for being a new drug candidate both with unlimited resources and cost-effective production. In this study, it was aimed to reveal the effects of isopropylchaetominine on cytotoxic, cytostatic, apoptotic and Wnt signaling pathways in brain, pancreatic and prostate cancer.

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Cancer is one of the leading causes of death worldwide, accounting for nearly 10 million deaths in 2020. Current treatment methods include hormone therapy, γ-radiation, immunotherapy, and chemotherapy. Although chemotherapy is the most effective treatment, there are major obstacles posed by resistance mechanisms of cancer cells and side-effects of the drugs, thus the search for novel anti-cancer compounds, especially from natural sources, is crucial for cancer pharmaceutics research.

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The species are considered to produce a plethora of several mycotoxins constituting a risk factor for both human and animal health. This work aimed mainly to explore the cytotoxicity of a combined mixture of altenuene (ALT), alternariol (AOH), tenuazonic acid (TeA), and altenuisol (AS) toxins produced by pathogenic toward human oral epithelial cells (PCS-200-014), lung fibroblast cells (WI-38), and male albino rats. The sequencing of the multi-locus, RNA polymerase second largest subunit (), glyceraldehyde-3-phosphate dehydrogenase (), and major allergen gene () was performed to infer relationships among isolated species.

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Endophytic fungi including black aspergilli have the potential to synthesize multiple bioactive secondary metabolites. Therefore, the search for active metabolites from endophytic fungi against pathogenic microbes has become a necessity for alternative and promising strategies. In this study, 25 endophytic fungal isolates associated with Malus domestica were isolated, grown, and fermented on a solid rice medium.

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Two new eremophilane-type sesquiterpenes, carperemophilanes A and B (1-2), three new maleimide-bearing compounds, carpesiumaleimides A-C (3-5), along with a known sesquiterpene, carabrol (6), were isolated from the ethanol extract of Carpesium abrotanoides L. Their structures were elucidated by analysis of their NMR and MS data as well as by comparison with the literature. The absolute configuration of carperemophilane A (1) was determined by single-crystal X-ray diffraction analysis.

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Three new cyclic heptapeptides (1-3) together with three known compounds (4-6) were isolated from a solid rice culture of the soil-derived fungus Clonostachys rosea. Fermentation of the fungus on white beans instead of rice afforded a new γ-lactam (7) and a known γ-lactone (8) that were not detected in the former extracts. The structures of the new compounds were elucidated on the basis of 1D and 2D NMR spectra as well as by HRESIMS data.

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A new cyclic pentapeptide, cotteslosin C (1: ), a new aflaquinolone, 22-epi-aflaquinolone B (3: ), and two new anthraquinones (9: and 10: ), along with thirty known compounds (2, 4:  - 8, 11:  - 34: ) were isolated from a co-culture of the sponge-associated fungus with . The new metabolites were only detected in the co-culture extract, but not when the fungus was grown under axenic conditions. Furthermore, the co-culture extract exhibited an enhanced accumulation of the known constituents versicolorin B (14: ), averufin (16: ), and sterigmatocyctin (19: ) by factors of 1.

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Co-cultivation of the endophytic fungus with on solid rice medium led to the production of four new naphthoquinone dimers, fusatricinones A-D (1-4), and a new lateropyrone derivative, dihydrolateropyrone (5), that were not detected in axenic fungal controls. In addition, four known cryptic compounds, zearalenone (7), (-)-citreoisocoumarin (8), macrocarpon C (9) and 7-hydroxy-2-(2-hydroxypropyl)-5-methylchromone (10), that were likewise undetectable in extracts from fungal controls, were obtained from the co-culture extracts. The known antibiotically active compound lateropyrone (6), the depsipeptides enniatins B (11), B1 (12) and A1 (13), and the lipopeptide fusaristatin A (14), that were present in axenic fungal controls and in co-culture extracts, were upregulated in the latter.

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Chemical investigation of aerial parts of Helichrysum italicum yielded two new pyrone derivatives (1 and 2) along with ten known compounds. The structures of the new compounds were established by 1D and 2D NMR spectra as well as by HRESIMS data. Compound 1 represented a rare dimer of substituted α- and γ-pyrone units.

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A comparative study on the metabolic profile of the sponge-associated fungus Aspergillus carneus using the OSMAC approach was conducted. The fungal strain was fermented on three different media including solid rice medium with or without sea salt and modified Czapek medium. Three new natural products, isopropylchaetominine (1), isoterrelumamide A (2) and 5'-epi-averufanin (3), together with fourteen known compounds (4-17) were isolated.

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A new depsidone derivative botryorhodine I (), along with eight known compounds () were obtained from solid rice cultures of the fungal strain, M4.2-2 isolated from a mangrove sediment sample. The structures of the isolated compounds were elucidated on the basis of 1 D and 2 D NMR analysis as well as by HRESIMS.

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Chemical investigation of a freshwater sediment-derived fungus, Penicillium sp. (S1a1), led to the isolation of three new tanzawaic acid derivatives, including penitanzchroman (1), tanzawaic acids Y (2) and Z (3), along with six known tanzawaic acid analogues (4-9), three known isochromans (10-12) and two known benzoquinones (13 and 14). The structures of the new compounds were established based on high-resolution mass spectrometry, and detailed analysis of one- and two-dimensional NMR spectroscopy.

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Article Synopsis
  • Researchers isolated ten new germacrane-type sesquiterpenoids from the plant Eupatorium chinense and determined their structures using NMR and MS data, along with literature comparisons.
  • * The absolute configuration of one compound, eupachinsin A, was identified through single-crystal X-ray diffraction analysis.
  • * Compounds 3 and 4 were found to be cytotoxic to a human breast cancer cell line (MDA-MB-231), with IC values of 0.8 and 3.4 μM, and compounds 3-5 also showed activity against human hepatocellular carcinoma cells (HepG) with IC values from 3.6 to 7.6 μM.
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The marine-derived fungus isolated from the Mediterranean sponge and cultured on solid rice medium yielded seventeen lactone derivatives including five butenolides (-), seven (3)-resorcylide derivatives (-), two butenolide-resorcylide dimers ( and ), and three dihydroisocoumarins (-). Among them, fourteen compounds (-, -) are new natural products. The structures of the isolated compounds were elucidated by 1D and 2D NMR (Nuclear Magnetic Resonance) spectroscopy as well as by ESI-HRMS (ElectroSpray Ionization-High Resolution Mass Spectrometry).

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A new alkaloid, 1,2-dihydrophenopyrrozin (1), along with five known compounds (2-6) was isolated from an axenic culture of the endophytic fungus, Bionectria sp., obtained from seeds of the tropical plant Raphia taedigera. Co-cultivation of this fungus either with Bacillus subtilis or with Streptomyces lividans resulted in the production of two new o-aminobenzoic acid derivatives, bionectriamines A and B (7 and 8) as well as of two additional known compounds (9 and 10).

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The anti-neuroinflammatory meroterpenoid citreohybridonol was isolated for the first time from a sponge-derived fungus Penicillium atrovenetum. In this study, in addition to isolation and structure featuring, its unambiguous absolute configuration was determined exclusively by single crystal X-ray diffraction. The C-17-keto tautomer was clearly observed in X-ray analysis.

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Background: Over the last two decades, deep-sea-derived fungi are considered to be a new source of pharmacologically active secondary metabolites for drug discovery mainly based on the underlying assumption that the uniqueness of the deep sea will give rise to equally unprecedented natural products. Indeed, up to now over 200 new metabolites have been identified from deep-sea fungi, which is in support of the statement made above.

Results: This review summarizes the new and/or bioactive compounds reported from deepsea- derived fungi in the last six years (2010 - October 2016) and critically evaluates whether the data published so far really support the notion that these fungi are a promising source of new bioactive chemical entities.

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Fourteen new natural products, namely, 2-[(Z)-styryl]-5-geranylresorcin-1-carboxylic acid (1), amorfrutin D (2), 4-O-demethylamorfrutin D (3), 8-geranyl-3,5,7-trihydroxyflavanone (4), 8-geranyl-5,7,3'-trihydroxy-4'-methoxyisoflavone (5), 6-geranyl-5,7,3'-trihydroxy-4'-methoxyisoflavone (6), 8-geranyl-7,3'-dihydroxy-4'-methoxyisoflavone (7), 3-O-demethyldalbinol (8), 6a,12a-dehydro-3-O-demethylamorphigenin (9), (6aR,12aR,5'R)-amorphigenin (10), amorphispironones B and C (11 and 12), resokaempferol 3-O-β-d-glucopyranosyl-(1→2)-β-d-glucopyranoside-7-O-α-l-rhamnopyranoside (13), and daidzein 7-O-β-d-glucopyranosyl-(1→2)-β-d-glucopyranoside (14), together with 40 known compounds, were isolated from the fruits of Amorpha fruticosa. The structures of the new compounds were elucidated by 1D and 2D NMR spectroscopic analysis as well as from the mass spectrometry data. ECD calculations were performed to determine the absolute configurations of 11 and 15.

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Scopulariopsis sp. isolated from the Red Sea hard coral Stylophora sp. yielded two new triterpenoids (1-2) and a new naphthoquinone derivative (8) when cultured on white beans.

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The endophytic fungus Aspergillus austroafricanus isolated from leaves of the aquatic plant Eichhornia crassipes was fermented axenically on solid rice medium as well as in mixed cultures with Bacillus subtilis or with Streptomyces lividans. Chromatographic analysis of EtOAc extract of axenic cultures afforded two new metabolites, namely, the xanthone dimer austradixanthone (1) and the sesquiterpene (+)-austrosene (2), along with five known compounds (3-7). Austradixanthone (1) represents the first highly oxygenated heterodimeric xanthone derivative.

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Chemical investigation of the MeOH extract of the sponge Acanthostrongylophora ingens afforded the new manzamine derivative ircinal E (1), in addition to six known metabolites (2-7). The structure of the new compound was unequivocally elucidated using one- and two-dimensional NMR spectroscopy, as well as high-resolution mass spectrometry. Compounds 1-6 exhibited strong to moderate cytotoxicity against the murine lymphoma L5178Y cell line with IC50 values ranging from 2.

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A new altersolanol derivative, 4-dehydroxyaltersolanol A (9), along with two known sesquiterpenoids, (S)-7'-hydroxyabscisic acid (7) and (S)-abscisic acid (8) were obtained from the endophytic fungus, Nigrospora oryzae, isolated from leaves of Combretum dolichopetalum. The host plant yielded six known compounds including ellagic acid (1), 3, 3', 4-tri-O-methylellagic acid (2), arjunolic acid (3), 4'-dihydrophaseic acid (4), echinulin (5) and arestrictin B (6). Close structural similarities with regard to compounds 4, 7 and 8 were observed between the metabolites from the host plant and those of the endophytic fungus.

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Phytochemical investigation of Aglaia duppereana flowers led to the isolation of a new rocaglamide derivative and twelve known congeners. The structure of the new compound was unambiguously elucidated by spectroscopic techniques (1D- and 2D-NMR, HRESIMS). The isolated compounds exhibited a potent cytotoxic activity against mouse lymphoma (L5178Y) cells with EC50 values ranging from 5.

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The endophytic fungus Penicillium citrinum was isolated from a fresh stem of the Moroccan plant Ceratonia siliqua. Extracts of P. citrinum grown on rice and white bean media yielded five new compounds, namely, citriquinochroman (1), tanzawaic acids G and H (2 and 3), 6-methylcurvulinic acid (4), 8-methoxy-3,5-dimethylisoquinolin-6-ol (5), and one new natural product, 1,2,3,11b-tetrahydroquinolactacide (6), which had previously been described as a synthetic compound.

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Three new polyketides ((-)-1, (+)-1, and 2) were isolated from the EtOAc extract of the fungus Embellisia eureka, an endophyte of the Moroccan plant Cladanthus arabicus (Asteraceae). The structures of these new compounds were determined on the basis of one- and two-dimensional NMR spectroscopy as well as by high-resolution mass spectrometry. The absolute configurations of (-)-1, (+)-1, and 2 were determined by TDDFT ECD calculations of solution conformers, online HPLC-ECD analysis, and the modified Mosher method.

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