Five new alkaloids from the endophytic fungus Penicillium sizovae in Ferula sinkiangensis

Five new alkaloids, ferupencines A-E, featuring a pyrrol-oxazine core with a C3- C4O2N framework, were isolated from the secondary metabolites of the endophytic fungus Penicillium sizovae residing in Ferula sinkiangensis. Their structures were elucidated through comprehensive 1D and 2D NMR spectroscopy, along with mass spectrometric analysis, experimental and calculated (ECD) spectra, and other complementary methods. The absolute configuration of compound 1 was determined via X-ray crystallography, supported by experimental and calculated electronic circular dichroism (ECD) data. Notably, this is the first report of these compounds being isolated from endophytic fungi. The cytotoxicity of ferupencines A-E (1-5) was evaluated against three human tumor cell lines: HeLa, SGC-7901, and SHG-44. Compound 2 exhibited moderate cytotoxic activity against HeLa and SGC7901 cells, with IC50 values of 18.6 mu M and 14.2 mu M, respectively. Additionally, compound 5 showed an IC50 value of 23.8 mu M against HeLa cells, indicating moderate cytotoxic potential.