The clecarmycins, new antitumor antibiotics produced by Streptomyces: fermentation, isolation and biological properties.

In the course of screening for microbial products with antitumor activity, new antitumor agents, clecarmycins, were isolated from culture broth of Streptomyces sp. DO-114. The antibiotics were produced in a fermentation medium supplemented with a highly porous polymer resin which adsorbs antibiotics and results in a increase of titer. Active materials were separated from the polymer resin by solvent extraction procedure and two components named clecarmycin A1 and C were isolated by silica gel column chromatography. These were active against bacteria, and showed antiproliferative activities against human HeLa S3 cells. Clecarmycins exhibited antitumor activity against leukemia P388 and sarcoma 180 in mice.