Two new N-acetyl-ᴅ-glucosamine derivatives, penichryfurans A (1) and B (2), were obtained from the fermentation of an endophytic fungus Penicillium chrysogenum which inhabited the marine medical red alga Grateloupia turuturu. Their structures were established by detailed spectroscopic analysis of 1D and 2D NMR in combination with HRESIMS data. The absolute configurations were determined by the (Mo2(OAc)4)-induced CD and comparison of the calculated and experimental electronic curcular dichroism (ECD) spectra. Both compounds were evaluated for their in vitro cytotoxic activities against A549, HeLa, and HepG2 cell lines, among which compound 1 exhibited strong cytotoxicity towards the HepG2 cell line with an IC50 value of 9.0 μM.
Keywords: Marine algae-derived fungus; Penicillium chrysogenum; cytotoxicity; penichryfuran; secondary metabolites.