Isolation of Two Streptothricin-like Antibiotics, Nos. 6241-A and B, as Inhibitors of de novo Starch Synthesis and Their Herbicidal Activity

Abstract

Two streptothricin-like antibiotics, Nos. 6241-A and B, were obtained as inhibitors of de novo starch synthesis in excised leaf segments of barnyard millet (Panicum crus-galli). No. 6241-B was identified as SF-701, and No. 6241-A was a new antibiotic, in which N, N-dimethylglycine was substituted for the N-methylglycine of No. 6241-B (SF-701). Both antibiotics also inhibited plant growth. The inhibitory activity of No. 6241-B (SF-701) was approximately ten times that of No. 6241-A. By foliar treatment, No. 6241-B (SF-701) showed remarkable herbicidal activity against barnyard millet at a concentration of more than 500 ppm with little phytotoxicity for the rice plant (Oryza saliva L. cv. Nihonbare).