Penicixanthene E, a new xanthene isolated from a mangrove-derived fungus Penicillium sp.

One new xanthene derivative, named penicixanthene E (1), together with one known compound 2, was isolated from the EtOAc extract of the endophytic fungus Penicillium sp. GXIMD 03101, which was identified from the mangrove Acanthus ilicifolius L. collected in the South China Sea. The structure of 1 was elucidated by 1D and 2D NMR spectral interpretation and HREISMS data. The absolute configurations of C-9 and C-11 in 1 were proposed based on electronic circular dichroism (ECD), but the configuration at C-3 in 1 was unassigned. Compound 1 represents a xanthene derivative that was first reported, in which carbon-carbon double bond has been reduced. The cytotoxic activities of all compounds were evaluated, the result showed that compound 1 has weak activity against pancreatic cancer SW1990.