Taichunins E-T, Isopimarane Diterpenes and a 20-nor-Isopimarane, from Aspergillus taichungensis (IBT 19404): Structures and Inhibitory Effects on RANKL-Induced Formation of Multinuclear Osteoclasts

Fifteen new isopimarane-type diterpenes, taichunins E-S (1-15), and a new 20-nor-isopimarane, taichunin T (16), together with four known compounds were isolated from Aspergillus taichungensis (IBT 19404). The structures of these new compounds were determined by NMR and mass spectroscopy, and their absolute configurations were analyzed by NOESY and TDDFT calculations of ECD spectra. Taichunins G, K, and N (3, 7, and 10) completely inhibited the receptor activator of nuclear factor-kappa B ligand (RANKL)-induced formation of multinuclear osteoclasts in RAW264 cells at 5 mu M, with 3 showing 92% inhibition at a concentration of 0.2 mu M.

Automated summary

Fifteen new isopimarane-type diterpenes and a new 20-nor-isopimarane, along with known compounds, were isolated from Aspergillus taichungensis. Some of the newly isolated compounds showed inhibitory effects on the formation of multinuclear osteoclasts, indicating potential biological activity.