Two New 4-Hydroxy-2-pyridone Alkaloids with Antimicrobial and Cytotoxic Activities from sp. GZWMJZ-606 Endophytic with Thunb.

Two new 4-hydroxy-2-pyridone alkaloids furanpydone A and B ( and ), along with two known compounds N-hydroxyapiosporamide () and apiosporamide () were isolated from the endophytic fungus sp. GZWMJZ-606 in Thunb. Furanpydone A and B had unusual 5-(7-oxabicyclo[2.2.1]heptane)-4-hydroxy-2-pyridone skeleton. Their structures including absolute configurations were determined on the basis of spectroscopic analysis, as well as the -ray diffraction experiment. Compound showed inhibitory activity against ten cancer cell lines (MKN-45, HCT116, K562, A549, DU145, SF126, A-375, 786O, 5637, and PATU8988T) with IC values from 4.35 to 9.72 µM. Compounds , and showed moderate inhibitory effects against four Gram-positive strains (, methicillin-resistant , , ) and one Gram-negative strain () with MIC values from 1.56 to 25 µM. However, compounds - showed no obvious inhibitory activity against two Gram-negative bacteria ( and ) and two pathogenic fungi ( and ) at 50 µM. These results show that compounds - are expected to be developed as lead compounds for antibacterial or anti-tumor drugs.