A new antitumor substance, BE-18591, produced by a streptomycete. I. Fermentation, isolation, physico-chemical and biological properties.

New antitumor substance, designated BE-18591, was isolated from the culture broth of a streptomycete, strain BA18591. The active principle was extracted from mycelium by methanol and purified by silica gel chromatography. BE-18591 inhibited the growth of MKN-45 human stomach cancer cell line as well as P388 cell line. In in vivo experiments, BE-18591 inhibited the growth of Ehrlich ascites tumor.BE-18591 showed antimicrobial activity against Gram-positive and some Gram-negative bacteria.