Screening For Immunosuppressants From Marine Micromonospora

742 strains of marine Micromonopsora were isolated from 157 samples including marine soils, sediments and marine organisms using four media and selective isolation techniques. They produced different bioactive secondary metabolites with immunosuppressive activities (7%) and antimicrobial activities against Gram positive bacteria (30%), Gram negetive bacteria (1%), Mycobacterium tuberculosis (2%) and fungi (3%).In the course of screening for novel immunosuppressants, two compounds FW635I1 and FW635I2 with immunosuppressive activities were extracted from the culture broth of a marine Micromonospora. The structures of FW635I1 and FW635I2 were determined by physico-chemical properties , ¹HNMR, ¹³CNMR and ¹³C DEPT analyses. Compound FW635I1 has a structure that resembles Daidzein, compound FW635I2 resembles Genistein. These two important isoflavones originally produced by soy plants. FW635I1 (Daidzein) and FW635I2 (Genistein) were found to possess immunosuppressive and antitumor activities and no antimicrobial activities. The producing strain was identified with Micromonospora carbonacea FIM 02-635 (16S rDNA GenBank Accession No. AY697299). The above findings have never been reported as we know.A lipopeptide compound FW523 with immunosuppressive activities was isolated from the culture broth of a marine Micromonospora, Micromonospora chalcea FIM 02-523(16S rDNA GenBank Accession No. DQ126264). The compound FW523 was purified and showed to have 5 components. A component FW523-3 was identified with a known lipopeptide antitumor antibiotic, Rakicidin B. Interestingly, we first found it of disrupting tumor cell F-actin synthesis , reducing mitochondrial membrane potential and having immunosuppressive activity being similar to Cyclosporin A, a powerful immunosuppressant in clinic. Compounds FW523-4 and FW523-5 are new analogue of Rakicidins.