Isolation of bioactive natural products from myxomycetes.

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 of slime molds, few studies have been made on the chemistry of myxomycetes. Cultivation of the plasmodium of myxomycetes in a practical scale for natural products chemistry studies is known only for very limited species. Here is described a review on the recent results on isolation of bioactive natural products from myxomycetes obtained in these two years in the laboratories. Spore germination experiments were studied 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. As a result, pyrroloiminoquinones, polyene yellow pigments, and a peptide lactone from cultured plasmodia of Didymium iridis, Physarum rigidum and P. melleum, respectively were isolated. New naphthoquinone pigments, cycloanthranilylprolines, tyrosine-kinase inhibitory bisindoles, and a cytotoxic triterpenoid aldehyde lactone were also isolated from field-collected fruit bodies of Cribraria purpurea, Fuligo candida, Tubifera casparyi, and Tubifera dimorphotheca, respectively.