Abstract
Biological research was made on peptimycin, a new antitumor antibiotic, which had been found by the author in a culture broth of a soil actinomyces. The peptimycin-producing strain was considered to be a new species. Peptimycin was found to be markedly inhibitory against Ehrlich carcinoma in both ascites and subcutaneous solid tumor type and also against sarcoma 180 in ascites type. It scarcely did morphological damage to the tumor cells both in vivo and in vitro. No transformation of peptimycin was recognized into such a substance as would give a morphological injury to the cells. It was concluded that peptimycin would presumably act on host body to vary the condition of the host and in consequence exhibit tumor-inhibitory effects in vivo. Peptimycin had no anti-microbial activity. The. LD50 in mice was 35.36mg/kg through intravenous route.
