Immunomodulatory constituents from an ascomycete, Chaetomium seminudum

A screening study focusing on immunomodulatory activity of the EtOAc extract of an Ascomycete, Chaetomium seminudum, has afforded a known epipolythiodioxopiperazine, chetomin (1), together with three new chetomin-related metabolites named chetoseminudins A (2), B (3), and C (4). Among these four metabolites, I and 2 have been deduced as the immunosuppressive features of this fungus.