A new isocoumarin from a starfish-associated fungus Aspergillus sp. WXF1904

A fungal strain WXF1904, was isolated from a starfish sample corrected in the South China Sea. According to its internal transcribed spacer (ITS) analysis, the strain was identified as a member of the genus Aspergillus and designated as Aspergillus sp. WXF1904. One new isocoumarin containing halogennamed 6-chloro-5, 7-dihydroxy-3, 8-dimethylisocoumarin (1), along with six known compounds pilobolusate (2), p-hydroxybenzaldehyde (3), methyl orsellinate (4), catechol (5), vanillic acid (6), and wasabidienone E (7), were isolated from the cultures of Aspergillus sp. WXF1904 by silica gel column chromatography, ODS gel column chromatography, and high performance liquid chromatography (HPLC). Their structures were elucidated by high resolution mass spectrometry (HR-MS), nuclear magnetic resonance (NMR) as well as literature comparison. The new compound 5-chloro-6, 7-dihydroxy-3, 8-dimethylisocoumarin and compound 2 showed weak acetylcholinesterase inhibitory activity.