The Secondary Metabolites And Their Bioactivities Of Two Gorgonian- Derived Fungus

For nearly 30 years, gorgonian, soft corals have become a hot point in the research of Marine natural products chemistry resources, had found a large number of bioactive secondary metabolites and many drug lead compounds. There are a lot of microorganisms in the coral and their surface, more and more secondary metabolites with pharmacologically activities, such as anti-bacterial, anti-tumor, and anti-viral, have been found from corals derived microorganisms, great attention have been made to the secondary metabolites from corals derived microorganisms, have become a new hot area of marine natural chemistry. In this study we got antiviral activity, cell toxicity, compounds from the secondary metabolites of the Gorgonian-Derived Fungus Cladosporium sp.and Aspergillus niger from the south china sea.By applying the methods of activity and chemical screening, we got the active strains from the source of gorgonian derived fungi in our library, using the rice solid culture medium for cultivating the active strain of gorgonian derived fungus Cladosporium sp.and Aspergillus niger (TA01-24). Many kinds of chromatographic separation technology (HPLC Sephadex LH-20, Sigel, ODS) were used to isolate and purifiy the secondary metabolites. Modern spectroscopic analysis techniques (CD, MS, NMR, IR, UV) were used to identify the structure of these secondary metabolites. All of the compounds were evaluated by four bioactive models, including lethality to brine shrimp (Artimia salina), cytotoxic activity, antiviral activity, and antibacterial activity.Eight compounds (1-8) were isolated and identified from the gorgonian derived fungus Cladosporium sp (RA07-1), including one double ring lactam compound (1), six large ring lactone compounds (2-7) and one five-membered ring lactone compound (8). Compound 1 is a lactam compound have very special structure with two ring, NMR chemical quantitative calculation method is used to verified its planar structure, the measureed optical value and its calculation of optical compared to determined the absolute configuration of compound 1, C-8 is 85. The absolute configuration of compound 2 is determined by the Mosher method, get the absolute configuration of 4R,5R,11R.Fourteen (9-22) compounds were isolated and identified from the gorgonian derived fungus A. niger (TA01-24), including seven naphthopyranone compounds (9-15), three coumarin dimers compounds (16-18), and four other compounds (19-22). Compounds 9-15 are naphthopyranone compounds, which are the main secondary metabolites of the fungus Aspergillus niger. Compounds 5 and 6 are monomer of naphthopyranone compounds, and 11-15 are dimers of 9 and 10. Dimers 11-15 have no chiral carbon but a chiral axis in their structures, so every dimmer possesses two different absolute configurations (R and S). CD spectra are used to determined the absolute configurations of these dimmers. Compared their cotton effects in CD spectra with thosereported in literatures indicated that all dimers possess S configuration.The secondary metabolites (1-22) from Cladosporium sp (RA07-1) and Aspergillus niger (TA01-24) were evaluated lethal to brine shrimp (Artimia salina), cytotoxic, antiviral, and antibacterial activities. Compounds 9,10, and 12 showed potent antiviral activities against FMD viru (EV71) with the IC50 values of 43.9μM, 10.3 μ,54.7μM respectively, which stronger than the positive control ribavirin with the IC50 value of 256μ. Compounds 14 and 21 show antiviral activity against herpes simplex virus with the IC50 values of 42.3 μM and 117.5μM, respectively (ribavirin IC50=128/uM). Compound 1 showed cytotoxic toward HeLa, P388, HT-29, A549 with IC50 values of 0.76μM,1.35 μM,2.48 μM,3.11 μM respectively.Compound 19 showed potent cytotoxic toward HeLa, Hep-2, RD, A549, Vero with IC50 values of 2.30μ,0.88μM,0.034 μ,0.83 μ,3.08μM respectively, stronger than the positive control adriamycin (IC50 values 0.43 μM,0.36 μ,0.99 μM,14.29 μM,2.03 μM respectively).This study got double ring lactam, macrolide, naphthopyranone dimers compounds, coumarin dimers compounds from the gorgonian derived fungus Cladosporium sp and Aspergillus niger. Determined the antiviral and cytotoxic activity of these compounds. Provide the basis and the data for the development and application of the marine natural products.