BE-14348 SUBSTANCES, NEW SPECIFIC ESTROGEN-RECEPTOR BINDING INHIBITORS - PRODUCTION, ISOLATION, STRUCTURE DETERMINATION AND BIOLOGICAL PROPERTIES

Streptomyces graminofaciens BA14348, isolated from a soil sample, was found to produce new specific inhibitors of estrogen binding to its receptor. Five related substances, BE-14348A approximately E, were isolated, and their structures were determined by analyses of spectral properties. Of these substances, A was identical with the known flavanone, naringenin. On the other hand, B, C, D and E were all new compounds; the structure of B was determined to be 2(S):3(S)-3-methyl-4',5,7-trihydroxyflavanone, C was a racemic mixture of 2(S):3 (R) and 2(R):3(S)-3-methyl-4',5,7-trihydroxyflavanone; D and E were 8-chloro derivatives of B and C, respectively.