Antitumor and immunosuppressive activities of lankacidin-group antibiotics: structure-activity relationships.

The antitumor and immunosuppressive activities of the lankacidin-group antibiotics were studied in mice. Seventeen of 29 newly prepared lankacidin-group antibiotics, including 14-derivatives of lankacidin C, lankacidinol, isolankacidinol, and lankacidinol 14-acetate, possessed considerable antitumor activity against ascites 6C3HED/OG lymphosarcoma. Comparative studies on the antitumor activity of lankacidin C and eight of its derivatives against L1210 leukemia and solid 6C3HED/OG lymphosarcoma demonstrated that replacement of the hydroxyl group at position 8 or 14 of lankacidin C by an acyloxy group potentiated antitumor activity. However, these modifications of lankacidin C resulted in reduction of the immunosuppressive activity.