A novel tricyclic diterpenoid antibiotic, brasilicardin A, was isolated from the culture broth of Nocardia brasiliensis IFM0406. The antibiotic exhibited immunosuppressive activity in a mouse mixed lymphocyte reaction (MLR)assay system and its IC50 value was 0.057jug/ml. Although the inhibitory activity of cyclosporin A (CyA) against IL-2 production was confirmed in the MLRassay system, brasilicardin A did not have the activity. The results of in vitro toxicity testing of brasilicardin A against various human cell lines were comparedwith those of CyA.During our continuing search for bioactive metabolites from pathogenic Nocardia, we isolated and reported new antibiotics, brasiliquinones A~C1>2), brasilidine A3) and nocardicyclins A, B4). Recently we also reported a new 32-membered macrolide antibiotic, brasilinolide A, with immunosuppressive activity from N. brasiliensis IFM 04065>6). Further studies on the active metabolites from the culture broth of strain IFM 0406 led to the isolation of a new terpenoid antibiotic, brasilicardin A.In this paper we report on the fermentation, isolation and biological activity of brasilicardin A. FermentationThe seed culture was prepared by inoculating mycelial fragments of strain IFM 0406 into a 500 ml-Erlenmeyer flask containing 150ml of brain heart infusion medium (BHI, Difco) supplemented with 1% glucose and 1% glycerol. The culture was performed at 32°C for 96 hours on a rotary shaker at 300rpm. The seed culture (150ml) was then inoculated into a 20 liter jar fermenter containing the production medium (15 liters) consisting of2% glycerol, 1%polypeptone and 0.5% meat extract in distilled water. The pH was adjusted to 7.0 with 1 m NaOHbefore sterilization.Adekanol (Asahi Denka Co., Ltd.) was added as the antifoam. Fermentation was carried out at 32°C for 3 days under aeration of 15 liters/minute and agitation at 200 rpm. HPLCAnalysis of Brasilicardin AThe amount of brasilicardin A in the culture broth was estimated by HPLCanalysis using a reverse phase column (LiChrospher 100 RP-18 endcapped, 4mmx125 mm,Merck). The analysis was carried out as follows:

A new 32-membered macrolide antibiotic, brasilinolide A was isolated from the fermentation broth of Nocardia sp. IFM0406. The producer was identified as Nocardia brasiliensis. The antibiotic was only active against Aspergillus niger, but not active against other fungi including yeasts as well as other filamentous like fungi and bacteria. Brasilinolide A exerted an immunosuppressive activity in the assay system of a mixed lymphocyte reaction (MLR). Immunosuppressive agents which attack specific target sites of immunocompetentcells are good candidate for immunotherapy. The examples of useful drugs of this type are cyclosporin A1} and FK-5062). We had reported that some opportunistic pathogenic Nocardia, such as Nocardia otitidiscaviarum and Nocardia brasiliensis, produce novel bioactive substances3~5). In the course of continuing search for bioactive substances including immunosuppressive agents from Nocardia, we found

A novel tricyclic metabolite, brasilicardin A (1), with potent immunosuppressive activity has been isolated from the cultured broth of the actinomycete Nocardia brasiliensis IFM 0406, and the structure including absolute stereochemistry was established on the basis of spectroscopic data, chemical means, and X-ray analysis. Brasilicardin A (1) is the first tricyclic compound consisting of an anti/syn/anti-perhydrophenanthrene skeleton with a rhamnose, an N-acetylglucosamine, and an amino acid moiety.