Stereochemical Investigations of Isochromenones and Isobenzofuranones Isolated from <i>Leptosphaeria</i> sp. KTC 727

Tayone, Wilanfranco Caballero; Honma, Miho; Kanamaru, Saki; Noguchi, Shogo; Tanaka, Kazuaki; Nehira, Tatsuo; Hashimoto, Minoru

doi:10.1021/np100838j

Cited by 45 publications

(57 citation statements)

References 10 publications

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“…Although the calculated absorption wavelengths did not fit exactly with the experimental peak positions, the general features of the ECD spectrum calculated for the 6a R ,9 R ,9a R ,10 S isomer showed a much better match with the experimental data than did the inverted spectrum calculated for its enantiomer (Figure 3). Differences between the calculated and experimental spectra presumably resulted from an overestimation of the UV absorbance in the calculations, or may be due to minor differences between calculated and solution conformers 19,20. These observations allowed us to propose the 6a R ,9 R ,9a R ,10 S absolute configuration for compound 1 .…”

Section: Resultsmentioning

confidence: 86%

Conithiaquinones A and B, Tetracyclic Cytotoxic Meroterpenes from the Mediterranean Ascidian Aplidium conicum

Menna¹,

Aiello²,

D'Aniello³

et al. 2013

Eur J Org Chem

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Chemical investigation of the Mediterranean ascidian A. conicum resulted in the isolation of two new meroterpenes, the conithiaquinones A (1) and B (2), in addition to two previously reported chromenols (3 and 4) and conicaquinones (5 and 6). The structures of conithiaquinones A and B were determined by interpretation of spectroscopic data, and regiochemical and stereochemical assignments were achieved with the aid of computational methods, including the recently developed DP4 NMR spectral prediction method. Both conithiaquinones A and B showed significant effects on the growth and viability of cells, with 1 showing interesting cytotoxicity against human breast cancer cells.

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Section: Resultsmentioning

confidence: 86%

Conithiaquinones A and B, Tetracyclic Cytotoxic Meroterpenes from the Mediterranean Ascidian Aplidium conicum

Menna¹,

Aiello²,

D'Aniello³

et al. 2013

Eur J Org Chem

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“…However, naturally occurring isobenzofuranones are few and mainly found in plants and endophytic fungi [26,27,28,29,30]. Moreover, the absolute configurations at the C-3 position of many substituted isobenzofuranone still remain unknown.…”

Section: Discussionmentioning

confidence: 99%

Pseudaboydins A and B: Novel Isobenzofuranone Derivatives from Marine Fungus Pseudallescheria boydii Associated with Starfish Acanthaster planci

et al. 2014

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Two novel isobenzofuranone derivatives, pseudaboydins A (1) and B (2), along with five known compounds, including (R)-2-(2-hydroxypropan-2-yl)-2,3-dihydro-5-hydroxybenzofuran (3), (R)-2-(2-hydroxypropan-2-yl)-2,3-dihydro-5-methoxybenzofuran (4), 3,3′-dihydroxy-5,5′-dimethyldiphenyl ether (5), 3-(3-methoxy-5-methylphenoxy)-5-methylphenol (6) and (−)-regiolone (7), were isolated from the culture broth of the marine fungus, Pseudallescheria boydii, associated with the starfish, Acanthaster planci. Their structures were elucidated primarily based on NMR and MS data. The absolute configurations of 1–4 were determined by CD spectroscopy and single-crystal X-ray diffraction studies. The cytotoxic and antibacterial activities of 1–4 were evaluated. Pseudaboydin A (1) showed moderate cytotoxic activity against human nasopharyngeal carcinoma cell line HONE1, human nasopharyngeal carcinoma cell line SUNE1 and human glandular lung cancer cell line GLC82 with IC50 values of 37.1, 46.5 and 87.2 μM, respectively.

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“…This provided five metabolites, two of which were identified by dereplication. Compound 8 (5 mg) was determined to be ( R )-4,8-dihydroxy-6-methoxy-4,5-dimethyl-3-methyleneisochroman-1-one 13,14 and 9 (20 mg) was identified as ( R )-7-hydroxy-3-(( S )-1-hydroxyethyl)-5-methoxy-3,4-dimethylisobenzofuran-1(3 H )-one. 14 The absolute configurations of the metabolites were confirmed by comparisons of their circular dichroism data to those reported by Tayone et al 14 .…”

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confidence: 99%

Secondary metabolites produced by fungi derived from a microbial mat encountered in an iron-rich natural spring

Gerea

Branscum

King

et al. 2012

Tetrahedron Letters

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A collection of fungal isolates was obtained from a complex microbial mat, which occupied an iron-rich freshwater spring that feeds into Clear Creek, Golden, Colorado, USA. Two of the fungal isolates, a Glomeromycete (possible Entrophospora sp.) and a Dothideomycete (possible Phaeosphaeria sp.), were investigated for bioactive secondary metabolites. In total, six new compounds consisting of clearanols A–E (5, 6, 10–12) and disulochrin (7) were purified and their structures were determined. Disulochrin exhibited modest antibacterial activity against methicillin-resistant Staphylococcus aureus, whereas clearanol C showed weak inhibitory activity against Candida albicans biofilm formation.

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Stereochemical Investigations of Isochromenones and Isobenzofuranones Isolated from Leptosphaeria sp. KTC 727

Cited by 45 publications

References 10 publications

Conithiaquinones A and B, Tetracyclic Cytotoxic Meroterpenes from the Mediterranean Ascidian Aplidium conicum

Conithiaquinones A and B, Tetracyclic Cytotoxic Meroterpenes from the Mediterranean Ascidian Aplidium conicum

Pseudaboydins A and B: Novel Isobenzofuranone Derivatives from Marine Fungus Pseudallescheria boydii Associated with Starfish Acanthaster planci

Secondary metabolites produced by fungi derived from a microbial mat encountered in an iron-rich natural spring

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