Osteoclastogenesis Regulation Metabolites from the Coral-Associated Fungus Pseudallescheria boydii TW-1024-3

Three new compounds (9–11) were isolated together with eight known analogues from the fungus Pseudallescheria boydii associated with the South China Sea soft coral Sinularia sandensis. The structures of the new compounds were elucidated on the basis of the spectroscopic analysis, and the absolute configurations including the sulfur stereogenic center of a sulfoxide moiety were determined by comparison of experimental ECD spectra to TDDFT/ECD calculations. Epimeric chiral sulfoxides differing in the absolute configuration of the sulfur chirality center could be efficiently distinguished and assigned by comparing the experimental ECD to those of calculations for the sulfur epimers. In the in vitro biotests for osteoclastogenesis effects, compounds 1, 5, 7, and 10 exhibited a stimulatory activity, while compound 3 displayed an inhibitory activity.