Novel 6/7/6 ring system diterpenoids and cytochalasins from the fungus Eutypella scoparia GZU-4-19Y and their anti-inflammatory activity

Two new compounds eutyditerpenoid A (1) and seco-phenochalasin B (5), together with seven known compounds diaporthein A (2), aspergillon A (3), phenochalasin B (4), cytochalasins Z24 and Z25 (6 and 7), scoparasins A and B (8 and 9) were isolated from marine-derived Eutypella scoparia GZU-4-19Y. Among them, eutyditerpenoid A (1) with a rare 6/7/6 ring system possesing an anhydride moiety was the first example in the pimarane-type diterpenoids. Their structures were determined based on spectroscopic methods and the electronic circular dichroism (ECD) calculations. In the bioassays, all of the isolates were evaluated for their inhibitory activity against NO production induced by lipopolysaccharide in RAW 264.7 cells. Compounds 3 and 7 showed potent NO inhibition activity with IC50 values of 2.1 and 17.1 μM respectively, and the former also significantly suppressed the protein expression of iNOS and COX-2 at the concentration of 2.5 μM.