Xanthones and oxepino[2, 3-b]chromones from three endophytic fungi.
Chemistry
; 15(44): 12121-32, 2009 Nov 09.
Article
en En
| MEDLINE
| ID: mdl-19777508
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.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Oxepinas
/
Cromonas
/
Xantonas
/
Hongos
Idioma:
En
Revista:
Chemistry
Asunto de la revista:
QUIMICA
Año:
2009
Tipo del documento:
Article
País de afiliación:
Alemania
Pais de publicación:
Alemania