Bistachybotrysin K, one new phenylspirodrimane dimer from Stachybotrys chartarum with potent cytotoxic activity.

Bistachybotrysin K (1), one new phenylspirodrimane dimer with a central 6/7 oxygen heterocycle core, was isolated from the fungus Stachybotrys chartarum CGMCC 3.5365. Its structure was elucidated by extensive spectroscopic data and single-crystal X-ray diffraction. Compound 1 showed significant cytotoxicity against human tumor cell lines HCT116, NCI-H460, BGC823, Daoy, and HepG2 with IC₅₀ values in the range of 1.1–4.7 µM. [ABSTRACT FROM AUTHOR]