[Advances of the novel immunosuppressant brasilicardin A]

Brasilicardin A (BraA) is a natural diterpene glycoside isolated from the pathogenic actinomycete Nocardia brasiliensis IFM 0406 with highly potent immunosuppressive activity (IC₅₀=0.057 μg/mL). BraA potently inhibits the uptake of amino acids that are substrates for amino acid transport system L of T cells, which is different from the existing clinical immunosuppressants. BraA is more potent in a mouse mixed lymphocyte reaction and less toxic against various human cell lines compared with the known clinical immunosuppressants, such as cyclosporin A, ascomycin and tacrolimus. Therefore, BraA attracted more attention as a new promising immunosuppressant. However, the development of this promising immunosuppressant as drug for medical use is so far hindered because BraA has the unusual and synthetically challenging skeleton and shows the low-yield production in the natural pathogenic producer. This review introduces the molecular structure of BraA, its activity, mechanism of action, chemical synthesis of BraA analogs, heterologous expression of gene cluster, and an application of combining microbial and chemical synthesis for production of BraA, with the aim to facilitate the efficient production of BraA and its analogs.