Stachybocins, novel endothelin receptor antagonists, produced by Stachybotrys sp. M6222. I. Taxonomy, fermentation, isolation and characterization.

Stachybocins A, B and C, novel endothelin (ET) receptor antagonists, were isolated from the culture filtrate of Stachybotrys sp. M6222. They were extracted with ethyl acetate and then purified by alumina and silica gel column chromatographies. The molecular formulae of stachybocins were determined to be C52H70N2O10 (stachybocin A) and C52H70N2O11 (stachybocins B and C). It was supposed that they consisted of spirobenzofuran and terpene units from NMR spectra. They showed the inhibitory activity of 125I-ET-1 binding to rate ETA, human ETA and human ETB receptors.