Isolation and structures of two novel anti-mite substances, AB3217-B and C.

We previously reported1} the isolation and structure determination of a novel anti-mite substance, AB3217-A (1), one of the components of an anti-mite substance complex produced by Streptomycesplatensis AB321 7. Following improvements in the isolation method of AB3217-Afrom cultured broth, we found that the strain produced two new minor components, AB3217-B (2) and C (3), which were structurally related to AB3217-A. In this paper, we wish to report the isolation and structural studies of the two components. A slant culture of strain AB3217 was inoculated into a 500-ml Sakaguchi flask containing 125 ml of a medium consisting of dextrin 20 g, galactose 20 g, corn-steep liquor 5g, Bacto-soytone (Difco) lOg,