Daldinone derivatives from the mangrove-derived endophytic fungus Annulohypoxylon sp.

Endophytic fungi associated with Nigerian plants have recently generated significant interest in drug discovery programmes due to their immense potential to contribute to the discovery of new bioactive compounds. This study was carried out to investigate the secondary metabolites of endophytic fungi isolated from leaves of Newbouldia laevis, Ocimum gratissimum, and Carica papaya The plants were collected from Agulu, Anambra State, South-East Nigeria. Endophytic fungal isolation, fungal fermentation; and extraction of secondary metabolites were carried out using standard methods. The crude extracts were screened for antimicrobial activities using the agar well diffusion method, and were also subjected to high performance liquid chromatography (HPLC) analysis to identify their constituents. A total of five endophytic fungi was isolated, two from N. laevis (NL-L1 and NL-L2), one from O. gratissimum (SL-L1), and two from C. papaya (PPL-LAC and PPL-LE2). In the antimicrobial assay, the extracts of NL-L2, SL-L1, and PPL-LE2 displayed mild antibacterial activity against both Gram negative and Gram positive test bacteria. PPL-LAC extract showed mild activity only against S. aureus, while no antimicrobial activity was recorded for NL-L1 extract. All the endophytic fungal extracts showed no activity against the test fungi C. albicans and A. fumigatus HPLC analysis of the fungal extracts revealed the presence of ethyl 4-hydroxyphenyl acetate and ferulic acid in NL-L1; ruspolinone in NL-L2; protocatechuic acid, scytalone, and cladosporin in SL-L1; indole-3-acetic acid and indole-3-carbaldehyde in PPL-LE2; and indole-3-acetic acid in PPL-LAC. The findings of this study revealed the potentials possessed by these plants as source of endophytes that express biological active compounds. These endophytes hold key of possibilities to the discovery of novel molecules for pharmaceutical, agricultural and industrial applications.

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“…glaucoalbidum (107), Cladosporium tenuissimum (108), Annulohypoxylon sp. (109), Phomopsis sp. (78), and Scytalidium sp.…”

Section: Discussionmentioning

confidence: 99%

Screening of metabolites from endophytic fungi of some Nigerian medicinal plants for antimicrobial activities

Eze

Nnanna

Okezie

et al. 2019

The EuroBiotech Journal

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“…The previously proposed biosynthetic precursor to the daldinones, 1,8-dihydroxynaphthalene (DHN) was fed to the culture and resulted in accumulation of 738 and daldinone B, providing support for the hypothesis that the biosynthesis of these compounds begins with oxidative coupling of two DHN units. 286 An Ascomycota sp. yielded enantiomeric polyketide dimers 740 and 741, 287 whilst Aspergillus strains were the source of coumarin derivatives 742, 743, 288 chromone 744, 288 sterone 745, 288 anhydride derivative 746, 289 lipid amide 747, 289 xanthonoids 748-751 and derivative 752, 290 meroterpenoid 753 (ref.…”

Section: Fungi From Mangrovesmentioning

confidence: 99%

Marine natural products

et al. 2019

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“…In the apoptosis assays, the protein kinase inhibitor staurosporine (STS, 2.5 μM, #S5921, Sigma-Aldrich) was used as positive control, and standard growth medium supplemented with 0.1% DMSO was used as negative control. Determination of cell viability, western blot analysis and measurement of caspase-3 activity were performed as described previously ( Manns et al, 2011 ; Liu et al, 2017 ). All experiments were carried out in triplicate.…”

Section: Methodsmentioning

confidence: 99%

Induction of New Lactam Derivatives From the Endophytic Fungus Aplosporella javeedii Through an OSMAC Approach

et al. 2020

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Fermentation of the endophytic fungus Aplosporella javeedii on solid rice medium in presence of either 3.5% NaNO 3 or 3.5% monosodium glutamate caused a significant change of the fungal metabolite pattern compared to fungal controls grown only on rice. Chemical investigation of the former fungal extracts yielded 11 new lactam derivatives, aplosporellins A–K ( 2 – 12 ), in addition to the known compound, pramanicin A ( 1 ). All of these compounds were not detected when the fungus was grown on rice medium without these activators thereby indicating the power of this OSMAC approach. The structures of the new compounds were elucidated by one- and two- dimensional NMR spectroscopy, DFT-NMR calculations and by mass spectrometry as well as by comparison with the literature whereas the absolute configuration of the lactam core was determined by TDDFT-ECD and OR calculations. Pramanicin A ( 1 ) showed strong cytotoxicity against human lymphoma (Ramos) and leukemia (Jurkat J16) cells with IC 50 values of 4.7 and 4.4 μM, respectively. Mechanistic studies indicated that 1 activates caspase-3 and induces apoptotic cell death.

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Daldinone derivatives from the mangrove-derived endophytic fungus Annulohypoxylon sp.

Abstract: Three new benzo[j]fluoranthene metabolites, including an isolation artefact which induces intrinsic apoptosis and blocks autophagy, were isolated fromAnnulohypoxylonsp.

Cited by 33 publications

References 50 publications

Screening of metabolites from endophytic fungi of some Nigerian medicinal plants for antimicrobial activities

Screening of metabolites from endophytic fungi of some Nigerian medicinal plants for antimicrobial activities

Marine natural products

Induction of New Lactam Derivatives From the Endophytic Fungus Aplosporella javeedii Through an OSMAC Approach

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