1998 年 12 巻 2 号 p. 92-96
Our recent search for bioactive compounds from pathogenic Nocardia resulted in the isolation of a new antibiotic, brasilicardin A, from Nocardia brasiliensis IFM 0406, a clinical isolate from a lung nocardiosis patient. Brasilicardin A is a novel tricyclic diterpenoid containing an amino acid moiety, 3-hydroxybenzoate, a rhamnose and an N-acetylglucosamine unit. The antibiotic exhibited immunosuppressive activity in a mouse mixed lymphocyte reaction (MLR) assay system and its IC50 value was 0.057 μg/ml. Its immunosuppressive mechanism was considered to be different from that of the reference drug, cyclosporin A (CyA), because brasilicardin A has no inhibitory activity against IL-2 production in mouse MLR assay. Also new bioactive substances which were recently isolated by our research groups from pathogenic Nocardia are reviewed.