[Study on myxomycetes as a new source of bioactive natural products].

The Myxomycetes (true slime molds) are an unusual group of primitive organisms that may be assigned to one of the lowest classes of eukaryotes. As their fruit bodies are very small and it is very difficult to collect much quantity, few studies have been made on the chemistry of myxomycetes. We studied spore germination experiments of hundreds of field-collected myxomycetes collected in Japan, and succeeded in laboratory culture of plasmodia of several myxomycetes in a practical scale for natural products chemistry studies. Pyrroloiminoquinones, polyene yellow pigments, and a peptide lactone were isolated from cultured plasmodia of myxomycetes, while new naphthoquinone pigments, cycloanthranilylprolines, tyrosine-kinase inhibitory bisindoles, a cytotoxic triterpenoid aldehyde lactone, a dibenzofuran glycoside, and sterols possessing an unprecedented 2,6-dioxabicyclo[2.2.2] octan-3-one ring system, were also isolated from field-collected fruit bodies of myxomycetes.