The grass root endophytic fungus Flavomyces fulophazii: An abundant source of tetramic acid and chlorinated azaphilone derivatives

Fungal endophytes are remarkable sources of biologically active metabolites ecological and pharmacological significance. In this study, fungal isolates producing yellow pigments originating from grass roots, were identified as the recently described root colonizing dark septate endophyte (DSE), Flavomyces fulophazii (Periconiaceae, Pleosporales). While analyzing metabolite composition 17 fungus, 11 previously undescribed compounds, including four tetramic acids (dihydroxyvermelhotin, hydroxyvermelhotin, methoxyvermelhotin, oxovermelhotin), seven chlorinated azaphilones (flavochlorines A–G), together with known acid vermelhotin, tentatively by high performance liquid chromatography (HPLC)-tandem mass spectrometry (MS/MS). Among them, flavochlorine A, G, hydroxyvermelhotin vermelhotin could be isolated preparative HPLC, thus their structures also confirmed nuclear magnetic resonance (NMR) spectroscopy. Vermelhotin was found to main compound, reaching its maximum level 5.5 mg/g in vitro cultures a selected F. isolate. A significant amount HPLC these (4.8 mg 1.0 g lyophilized culture), confirming practical utility high-yield production. The compounds expressed no activity standardized plant bioassays (i.e., Lactuca sativa seed germination Lemna minor growth tests). An antiproliferative study moderate against panel twelve cancer cell lines, IC50 ranges 10.1–37.0 ?M, without inhibiting non-cancer Vero cells, suggesting selectivity towards cancers.