Proversilins A–E, Drimane-Type Sesquiterpenoids from the Endophytic Aspergillus versicolor

Five new drimane-type sesquiterpenoids, named proversilins A–E (1–5), were isolated from the endophytic fungus Aspergillus versicolor F210 isolated from the bulbs of Lycoris radiata. Their structures and absolute configurations were characterized by extensive spectroscopic analysis, including 1D and 2D NMR and HRESIMS data, comparison of experimental and calculated electronic circular dichroism data, and X-ray crystallography. Proversilins B–E (2–5) represent the first examples of natural products featuring an N-acetyl-β-phenylalanine moiety. Compounds 3 and 5 inhibited the growth of HL-60 cells with IC50 values of 7.3 and 9.9 μM, respectively.