NF-κB Inhibitory and Antibacterial Helvolic and Fumagillin Derivatives from Aspergillus terreus

Two new helvolic acid analogues ( 1 and 2 ) and one new fumagillin derivative containing an octahydroisobenzofuran moiety ( 3 ), together with four known compounds ( 4 – 7 ), were isolated from an Aspergillus terreus, isolated from soil collected from Mauna Kea, the highest mountain in Hawaii. Compound 4 was recorded in SciFinder with a CAS Registry Number of 1379525-35-5, but it was not documented in the cited reference ( ACS Chem. Biol . 2012, 7, 137). The structures of compounds 1 – 4 were elucidated by NMR spectroscopy and HRMS and ECD analysis. Compounds 5 and 6 showed significant inhibitory activity against NF-κB with IC 50 values of 2.7 ± 2.6 and 6.5 ± 0.8 μM, respectively. Compounds 1 and 2 were active against S. aureus with MICs of 6.25 and 6.25 μg/mL, respectively, while compound 5 inhibited E. coli with an MIC of 3.12 μg/mL.