New secondary metabolites from the endophytic fungus Aspergillus sp. from Tripterygium wilfordii

Abstract

One new 3,5-dimethylorsellinic acid (DMOA)-based meroterpenoid (1), one prenylated tryptophan derivative (2), together with ten known compounds (3−12) were isolated from the endophytic fungus Aspergillus sp. from Tripterygium wilfordii. Their structures and absolute configurations were determined by NMR spectroscopic data, HRESIMS data, UV and IR data as well as electronic circular dichroism (ECD) calculation. In structure, compound 1 was a rare example of DMOA-based meroterpenoid with a cis-fused C/D ring system, and compound 2 possessed an unusual (E)-oxime group. In bioactivity, the lovastatin analogues 5, 6, 9 and 10 showed potential immunosuppressive activity against anti-CD3/anti-CD28 monoclonal antibodies (mAbs)-irritated murine splenocytes proliferation, with IC50 values ranging from (5.30 ± 0.51) μM to (16.51 ± 1.62) μM.