New Naphthalene‐Chroman Coupling Products from the Endophytic Fungus, <i>Nodulisporium sp.</i> from <i>Erica arborea</i>

Dai, Jingqiu; Krohn, Karsten; Draeger, Siegfried; Schulz, Barbara

doi:10.1002/ejoc.200801106

Cited by 59 publications

(45 citation statements)

References 21 publications

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“…These data, and in particular the additional oxygen atom shown in the mass spectrum in comparison to normal xanthones, suggested a ring-enlarged xanthone, namely an oxepinoA C H T U N G T R E N N U N G [2, 3-b]chromen-6-one system, as present in fusidienol A (8 a). [40,41] The assignment was further confirmed by 1 H-1 H COSY, HMQC, and HMBC correlations ( Figure 1) and definitely established by X-ray crystallographic analysis of a single crystal of 1 (Figure 2). Enone 7 (Scheme 1) was prepared by oxidation of the allylic hydroxy group at C2 of microsphaeropsone A (1) with manganese dioxide; furthermore, single crystals suitable for X-ray crystallographic analysis could also be obtained (Figure 3).…”

Section: Resultsmentioning

confidence: 64%

Xanthones and Oxepino[2, 3‐b]chromones from Three Endophytic Fungi

Krohn

Kouam

Kuigoua

et al. 2009

Chemistry A European J

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Three new metabolites, microsphaeropsones A-C (1-3) with a unique oxepino[2,3-b]chromen-6-one (ring-enlarged xanthone) skeleton, were isolated from the endophytic fungus Microsphaeropsis species, co-occurring with their putative biogenetic anthraquinoide precursors citreorosein (4) and emodin (5). From another Microsphaeropsis species, large amounts of fusidienol A (8 a), smaller amounts of emodin (5), the known aromatic xanthones 9 a and 9 b, the new 3,4-dihydrofusidienol A (8 b), and the new aromatic xanthone 9 c were isolated. The endophyte Seimatosporium species produced a new aromatic xanthone, seimatoxanthone A (10), and 3,4-dihydroglobosuxanthone A (12), closely related to alpha-diversolonic ester (13) from Microdiplodia sp.. The structures were determined mainly by extensive 1D and 2D NMR experiments and supported by X-ray single-crystal analysis of 1 and the oxidation product 7. The absolute configurations of the microsphaeropsones A-C (1-3) were established by comparison of the electronic and vibrational circular dichroism (ECD and VCD) spectra of 1 with time-dependent DFT (TDDFT) and DFT calculations by using either the solid-state structures or DFT-optimized geometries as inputs. Preliminary studies indicated that 1, 2, and enone 7 showed antibacterial, fungicidal, and algicidal properties.

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Section: Resultsmentioning

confidence: 64%

Xanthones and Oxepino[2, 3‐b]chromones from Three Endophytic Fungi

Krohn

Kouam

Kuigoua

et al. 2009

Chemistry A European J

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“…C-2 carbon, according to heteronuclear correlations (HETCOR), is correlated with the H-2 (d 5.44, s) hydrogen. 13 C NMR spectrum also showed a signal at d 164.8 assigned to the lactone group carbonyl (C-1). The only olefinic proton H-2 (d 5.44) showed heteronuclear multiple bond correlations (HMBC) with C-1, C-3, and C-4.…”

Section: Resultsmentioning

confidence: 99%

“…Compound 1 was isolated from the apolar fractions of the ethyl acetate extract in amorphous white solid form, and its 1 H and 13 C NMR data showed the identity of the ergosterol peroxide steroid, 17 which is an steroid commonly isolated from fungi and reported to have anticancer activity. 19 Monocerin (2) 1 H NMR spectrum of 3 showed signals related hydrocarbon side chain, a methoxy group and olefinic methine unit presence.…”

Section: Resultsmentioning

confidence: 99%

“…(Xylariaceae) fungus extract, which was isolated from the woody plant species Erica arborea (Ericaceae), nodulisporina D, E and F compounds were obtained, having antifungal, antibacterial and algaecide activity. 13 From the endophytic fungus Ampelomyces sp., isolated from the medicinal plant Urospermum picroides (Asteraceae), 6-O-methylalaternina and altersolanol A compounds were isolated, which showed antimicrobial activity against Gram-positive pathogens Staphylococcus aureus, S. epidermidis and Enteorococcus faecalis. 14 Brazil is estimated to be home of about 20% of the world's biodiversity and is considered the country in the world with the largest number of endemic species.…”

Section: Introductionmentioning

confidence: 99%

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Annularins I and J: New Metabolites Isolated from Endophytic FungusExserohilum rostratum

Pinheiro¹,

Borges²,

Pina³

et al. 2016

Journal of the Brazilian Chemical Society

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The paper describes the isolation of ergosterol peroxide, monocerin, annularin I and annularin J compounds of Exserohilum rostratum biomass extracts. Compounds were isolated by silica gel column chromatography in polarity gradient and the structures were determined by nuclear magnetic resonance (NMR) and mass spectrometry (MS) methods. Monocerin, annularin I and annularin J compounds were tested against Escherichia coli, Pseudomonas aeruginosa and Bacillus subtilis bacteria and showed moderate activity. Annularin I and annularin J compounds are new natural products. Keywords: annularins, polyketides, E. rostratum, endophytic fungi IntroductionEndophytic microorganisms live in plants internal tissues without causing apparent disease to their hosts. 1 Endophyte microbial colonization can be demonstrated by isolating plant tissues disinfected through histological cut and by DNA amplification technique. 2 In tropical and temperate forests (which cover only 1.5% of the terrestrial surface), there are approximately 300,000 (three hundred thousand) plant species analyzed so far, homing more than 60% of the world's biodiversity. 3 Extreme diversity allows for the opportunity to discover new microorganisms that may be potential bioactive compounds producers for agriculture, industry and medicine. 4 There is a great interest in the study of endophytic microorganisms, including their application in pest biocontrol. Fungi are good secondary metabolite producers, and many have the same biological activity, 5-8 especially polyketides. For example, the polyketide citrinin isolated from Penicillium janthinellum completely inhibited the growth of Leishmania braziliensis.9 Some fungi species of Penicillium and Pestalotiopsis genera produce high diversity of polyketides with antimicrobial activity. 10,11In another study with a variety of endophytes isolated from Vigueira arenaria and Tithonia diversifolia fungal extracts, important antiparasitic and antimicrobial activities were observed in fungal extracts. 12 In the Nodulisporium sp. (Xylariaceae) fungus extract, which was isolated from the woody plant species Erica arborea (Ericaceae), nodulisporina D, E and F compounds were obtained, having antifungal, antibacterial and algaecide activity.13 From the endophytic fungus Ampelomyces sp., isolated from the medicinal plant Urospermum picroides (Asteraceae), 6-O-methylalaternina and altersolanol A compounds were isolated, which showed antimicrobial activity against Gram-positive pathogens Staphylococcus aureus, S. epidermidis and Enteorococcus faecalis.14 Brazil is estimated to be home of about 20% of the world's biodiversity and is considered the country in the world with the largest number of endemic species.15 About 270,000 plant species on this planet are estimated to harbor about 13.6 million unique endophytic fungal species, in addition to approximately 100,000 fungi species already known to date. Therefore, there are great chances of finding Pinheiro et al. 1433 Vol. 27, No. 8, 2016 new substances produced by endophytic fun...

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“…[2][3][4][5][6][7] This is probably due to their metabolic interactions with their environments. [5,8] As part of our ongoing screening for biologically active secondary metabolites from fungi, [1] we have reinvestigated the metabolites produced by the endophytic Fusidium sp., isolated from the leaves of Mentha arvensis growing in a meadow near Hahausen, Lower Saxony, Germany. Our previous chemical research on the extracts of this fungus resulted in the isolation of a new group of polycyclic lactones, [9] the fusidilactones B (3), A (4), and C (5) (Figure 1), the last possessing an unusual oxoadamantane skeleton.…”

Section: Introductionmentioning

confidence: 99%