3a-Hydroxysteroid dehydrogenase is one of the key enzymes involved in inflammatory processes. Hence, inhibitors of this enzyme are interesting as lead structures for the development of anti-inflammatory agents. In a screening for new microbial metabolites inhibiting 3ahydroxysteroid dehydrogenase we disclosed Streptomyces sp. HKI 0231 as the producer of new inhibitors, 0231A (1)and 023IB (2). Both compounds were formed as minor components in addition to angucyclin-type metabolites such as tetrangulol methylether. Here we report isolation and structure of these unusual polycyclic metabolites.