Isolation of One Sesquiterpenoid from the Endophytic Fungus Curvularia intermedia

Chemistry of Natural Compounds - One new natural product, cadinane-type sesquiterpenoid, (±)-(2S*,3S*)-dihydroxy-α-corocalene (1), has been isolated from the endophytic fungus Curvularia...     

Six new metabolites produced by Colletotrichum aotearoa 09F0161, an endophytic fungus isolated from Bredia oldhamii

Six new compounds, colletobredins A–D (1–4) and colletomelleins A and B (5 and 6), along with 12 previously identified compounds, were isolated from the culture broth of Colletotrichum aotearoa BCRC 09F0161, a fungal endophyte residing in the leaves of an endemic Formosan plant Bredia oldhamii Hook. f. (Melastomataceae). The structures of the new compounds were established by spectroscopic methods, including UV, IR, HR-ESIMS and extensive 1D and 2D NMR techniques. The effects of some isolates on the inhibition of nitric oxide (NO) production in lipopolysaccharide-activated murine macrophage RAW264.7 cells were evaluated. All these compounds inhibited NO production in activated macrophages without any cytotoxicity at a concentration of 100 μM. Of these isolates, 1 showed weak NO inhibitory activity with IC₅₀ value of 182.2 μM. To the best of our knowledge, this is the first report on isochroman glycoside metabolites (1–4) from the genus Colletotrichum.     

Secondary metabolites from the endophytic fungus <Emphasis Type="Italic">Annulohypoxylon boveri</Emphasis> var. <Emphasis Type="Italic">microspora</Emphasis> BCRC 34012

A chemical study on the n-BuOH-soluble fraction of the 95% EtOH extract of long-grain rice (Oryza sativa) fermented with the endophytic fungus Annulohypoxylon boveri var. microspora (BCRC 34012) has resulted in the isolation of one new natural azaphilone derivative, designated as annulohypoxyboverin (1) together with 12 known compounds, (3R,6R,7E)-3-hydroxy-4,7-megstigma-dien-9-one (2), α-tocopheryl quinone (3), isofraxidin (4), coumarin (5), cinnamic acid (6), a mixture of palmitic acid (7) and stearic acid (8), N-cis-feruloyltyramine (9), luteolin (10), kaempferol (11), kaempferitrin (12), and 4,5,4′,5′-tetrahydroxy-1,1′-binaphthyl (13). Annulohypoxyboverin (1) contains a dihydrobenzofuran-2,4-dione backbone, 1-hydroxyhexyl side chain, and one γ-lactone ring. Their structures were elucidated by spectroscopic analyses including 1D and 2D NMR experiments, and by HR-ESI-MS. The relative configuration of 1 was confirmed by NOESY experiment. Other known compounds were identified by comparing their spectral data with those of literature data.     

Secondary metabolites isolated from the fungus <Emphasis Type="Italic">Biscogniauxia cylindrospora</Emphasis> BCRC 33717

One new dihydroisocoumarin, (3S)-5-hydroxy-8-O-methylmellein (1), as well as nine known compounds, 5-formylmellein (2), mellein-5-carboxylic acid (3), 5-hydroxymethylmellein (4), 3β-hydroxystigmast-5- en-7-one (5), N-trans-feruloyltyramine (6), N-cis-feruloyltyramine (7), vanillic acid (8), methyl paraben (9), and syringaldehyde (10), were isolated from the n-BuOH-soluble fraction of the 70% EtOH extract of rice fermented with the endophytic fungus Biscogniauxia cylindrospora (BCRC 33717). Their structures were elucidated by 1D and 2D NMR spectroscopy together with HR-ESI-MS analysis and comparison of the spectroscopic data with those reported for structurally related compounds.