Structure and absolute configuration assignments of ochracines F-L, chamigrane and cadinane sesquiterpenes from the basidiomycete Steccherinum ochraceum HFG119

Abstract

Ochracines F-L (1-7), seven previously undescribed chamigrane and cadinane sesquiterpenoids, together with four known chamigranes were isolated from cultures of the wood-decaying fungus Steccherinum ochraceum HFG119. Ochracines F-L were structurally characterized by extensive analysis of HRMS and NMR spectroscopic data. The relative configurations were assigned through a combination of NOE correlations and J-based configuration analysis (JBCA), while the absolute configurations were determined by X-ray single-crystal diffraction, and calculated methods (ECD, [α], ¹³C NMR). All the new isolates were evaluated for their cytotoxicity against five human cancer cell lines HL-60, SMMC-7721, A549, MCF-7, and SW-480, and inhibitory activity on NO production in RAW 264.7 macrophages.