Citrifuran E–I, Five Dimeric Polyketides With Potential Anti‐inflammatory Activity From <i>Aspergillus</i> sp. AWG 1–15

Five novel dimeric polyketides, citrifuran E-I (1-5), were isolated from the fungus Aspergillus sp. AWG 1-15. These polyketides were rare heterodimers of azaphilone and furanone derivatives. Their relative and absolute configurations were determined based on high-resolution electrospray ionization mass spectrometry and spectroscopic analyses (one- and two-dimensional nuclear magnetic resonance), electronic circular dichroism calculations, and chemical derivatization. All compounds were assessed for anti-inflammatory activity by measuring their effects on nitric oxide production induced by lipopolysaccharide in RAW 264.7 cells. Compounds 1-4 exhibited moderate inhibitory activity, with the minimum inhibitory concentration (IC₅₀) values ranging from 12.6 to 37.3 µM, compared to the positive control N^G-monomethyl-L-arginine (IC₅₀ = 40.6 µM).