Cribrarione C, a Naphthoquinone Pigment from the Myxomycete Cribraria meylanii

Chemical investigation of field-collected fruit bodies of the myxomycete Cribraria meylanii resulted in the isolation of a naphthoquinone pigment, cribrarione C, and its structure was elucidated by spectral data as 2,5,6,7-tetrahydroxy-1,4-naphthoquinone (1). This compound (1) had been synthesized previously, while it was isolated here for the first time as a natural product, and its NMR and MS data are described in this study. During our search for bioactive natural products from myxomycetes, we have isolated a number of new bioactive secondary metabolites with unique bioactivities, such as a chlorinated polyene-pyrone, tyrosine-kinase inhibitory bisindole alkaloids, Wnt-signal inhibitory peptide, TNF-related apoptosis inducing ligand (TRAIL) resistance overcoming cycloanthranilylproline, and cytotoxic triterpenoid aldehyde lactone. 1) Myxomycetes (true slime molds) are an unusual group of primitive organisms that may be assigned to one of the lowest classes of eukaryotes, and chemical studies of the secondary metabolites of the myxomycetes had been limited before our studies. 2)