Absolute Configuration and Biological Activities of Meroterpenoids from an Endophytic Fungus of Lycium barbarum

Eleven new meroterpenoids, bipolahydroquinones A-C (1-3), cochlioquinones I-N (4-8 and 11), and isocochlioquinones F and G (9 and 10), together with six known ones, were obtained from an endophytic fungus Bipolaris sp. L1-2 from Lycium barbarum. Compound 2 is the first example of cochlioquinone derivatives possessing a benzofuran moiety. The structures and absolute configurations of the new compounds were elucidated by spectroscopic data interpretation, single-crystal X-ray diffraction analysis, chemical transformations, and biosynthetic considerations. Compounds 3, 4, and 6-8 showed cytotoxicity against NCI-H226 and/or MDA-MB-231 with IC₅₀ values ranging from 5.5 to 9.5 μM.