New polyketides and diterpenoid derivatives from the fungus Penicillium sclerotiorum GZU-XW03-2 and their anti-inflammatory activity.

Abstract Two new compounds, named penisclerotiorin A (1) and diaporthein C (8), and a new natural product, penidepsidone A (4), together with five known compounds (2, 3, 5–7) were isolated from the fungus Penicillium sclerotiorum GZU-XW03–2. Their structures were assigned using spectroscopic methods, quantum chemical calculations, and single-crystal X-ray diffraction analysis. Penisclerotiorin A (1) that belongs to the highly oxidized diphenyl ether is rare found in natural sources, and it was the sixth example of highly oxidized diphenyl ether analogues in natural sources. Penidepsidone A (4) is a new natural product and no any NMR spectral data were reported to date, in this paper, we firstly used the NMR calculations to confirm the intact structure by comparison of the experimental NMR data. Diaporthein C (8) represents the third example of pimarane diterpenes bearing a double bond at C-8 and C-9. In the bioassays, all of the isolates (1–8) were tested for their anti-inflammatory effects on the production of nitric oxide in lipopolysaccharide-induced microglial cells (RAW 264.7 cells). Compounds 2, 3 and 6 showed potent anti-inflammatory effects than the positive control (indomethacin, IC50, 24.0 μM) with IC50 values of 11.52, 8.13 and 21.27 μM, respectively.