Spergualin: a new antitumour antibiotic.

Spergualin was isolated from the culture filtrate of Bacillus laterosporus as an antitumour substance. It had a unique structure and was shown to have chemotherapeutic effects on mouse transplantable leukaemias such as L-1210, P-388, P-815, C-1489, EL-4 and RL male 1. It was especially effective to L-1210 leukaemia and the leukaemia-bearing mice were even curable by the optimal dose of this drug. When the spergualin-treated cured mice were inoculated again by L-1210 cells, those leukaemic cells did not grow in the animals suggesting that specific immunity to L-1210 had been induced. In this induction of immunity cytotoxic T lymphocytes were suggested to be involved. Cytostatic effect of spergualin in cell culture was dependent on the content of amine oxidase in serum. In the study of structure-activity relationship, the 15-hydroxy group was found to be not necessary, while the spermidine moiety was essential for antitumour activity. 15-Deoxy derivative of spergualin was found to be more potent in antitumour activity.