New class azaphilone produced by a marine fish-derived Chaetomium globosum. The stereochemistry and biological activities

Four new metabolites, chaetomugilins P-R and 11-epi-chaetomugilin I, were isolated from a strain of Chaetomium globosum originally obtained from the marine fish Mugil cephalus, and their absolute stereostructures were elucidated on the basis of spectroscopic analyses, including 1D and 2D NMR techniques and various chemical transformations. Particularly, the skeleton of chaetomugilin P is different from that of other azaphilones isolated from this Fungal strain to date. In addition, these compounds significantly inhibited the growth of cultured P388, HL-60, L1210 and KB cell lines.