Three new highly-oxygenated metabolites from the endophytic fungus Cytospora rhizophorae A761

Abstract

Cytosporaphenones A-C, one new polyhydric benzophenone and two new naphtopyrone derivatives, along with eight known ones, were isolated from Cytospora rhizophorae, an endophytic fungus from Morinda officinalis. Their structures were fully characterized by means of detailed spectroscopic analysis and X-ray single crystal diffraction. To our knowledge, the three new compounds were the most highly oxygenated metabolites of their families discovered in nature. Moreover, all of the compounds were evaluated for in vitro cytotoxic activities against MCF-7, NCI-H460, HepG-2 and SF-268 tumor cell lines, and the new compound 1 exhibited weak growth inhibitory activity against the tumor cell lines MCF-7 and HepG-2 with IC₅₀ values of 70 and 60μM, respectively.

Keywords: Cytospora rhizophorae; Cytosporaphenones A-C; Cytotoxicity; Highly-oxygenated metabolites; Morinda officinalis.