Novel geranylhydroquinone derived meroterpenoids from the fungus Clitocybe clavipes and their cytotoxic activity.

Three novel geranylhydroquinone derived meroterpenoids, named clavilactones J and K (1 – 2) and clavipol C (3), were isolated from the basidiomycete Clitocybe clavipes. Their structures were unambiguously identified by extensive spectroscopic data analysis, and the electronic circular dichroism (ECD) calculation, Gauge-Including Atomic Orbitals (GIAO) NMR calculations and Mo 2 (OAc) 4 -induced electronic circular dichroism experiments were used to establish their absolute configurations. Compound 1 , with two epoxy groups located at the 10-membered carbocycle, is uncommon in the reported meroterpenoids from C. clavipes. All the obtained compounds (1–3) were tested for their cytotoxic activity against human tumor cell line HGC-27 by using the MTT assay. All the compounds exhibited moderate cytotoxic activities against HGC-27 cell with IC 50 values ranging from 33.5 to 56.6 μM. [Display omitted] [ABSTRACT FROM AUTHOR]