Bioactive Secondary Metabolites From Two Strains Of Marine Fungi In Ligia Exctica

Symbiotic fungi, a major group of special microorganisms, can produce novel bioactive compounds and is an important source of new bioactive natural products. In order to get new lead compounds with novel structures and potent bioactivities, two strains of symbiotic fungi PO4 and MO4, isolated from marine isopod Ligia exctica, were chosen to investigate the secondary metabolites of them by using OSMAC method.31 compounds were seperated and purified by making full use of silica gel thin layer chromatography, silica gel column chromatography, Sephadex LH-20 column chromatography, ODS column chromatography, HPLC and so on.24 compounds (1-24) and 7 compounds (25-31) were isolated from the cultrue broth of fungi Pleospora sp. PO4 and Cephalosporium sp. MO4. The structures of all the 31 pure compounds were determined by spectral analysis of NMR, MS, UV, IR, CD.Among them there are 8 hydroanthraquinone derivatives (4-9,21-22),8 anthraquinone dimers (1,10-16),4 leptosphaerone derivatives (17-20), a phthalic acid (2), a 2,5-alkylresorcinol (3), a sesterterpene (23), an adenosine derivatives (24),5 diketopiperazines (25-28,30),2 resorcinol derivatives (29,31), and compounds 17-20 contained novel structures, compound 25 was isolated as natural products for the first time, and compound 1 was isolated as pure compound for the first time.The MIC value of some compounds were tested by micro broth dilution method. The results indicated that compounds 1 and 17-20 showed good antibacterial activity against S. epidermidis CMCC26069.