Secondary Metabolites From A Sponge Plakortis Sp. XSA-02

Natural products are the basic units of survival and evolution of marine organisms,most of these secondary metabolites have chemical and ecological functions.Researchers use explore these natural products to explain the process of life and benefit mankind.Sponges are a class of benthic marine organisms.Special growth environments such as high pressure,low temperature,low light,high salt,and low oxygen have created unique enzyme reaction systems and biosynthetic pathways.Sponges produce an array of chemical defense molecules to protect themselves against predators,and some of them show a spectrum of pharmaceutical functions.The structural features derived from sponges may provide useful data for chemo-taxonomy.In this thesis,a sponge Plakortis sp.is selected for chemical examination.The sponges collected from the South China Sea which were immediately stored in ethanol.The ethyl acetate extract were isolated with silica gel,ODS column chromatograph,sephedex LH-20column chromatograph and HPLC,resulting in the isolation of 32 polyketides,including 20new compounds at the guidance of MS²-based molecular networking.The compounds were identified by spectroscopic methods（NMR,HRESIMS,NMR calculation）,CD analysis,ECD calculation,[Rh₂（OCOCF₃）₄]method,chemical degradation method.Some compounds were subjected to antibacterial,cytotoxic,anti-HBV and NF-κB inhibitory activities,and a preliminary structure-activity relationship was discussed.It was found that compound 16showed weak inhibitory effect on Staphylococcus aureus with MIC of 16μg/m L,compound 8（10μmol/L）inhibited HBV-DAD replication with an inhibition rate of 70%,and the C-6methyl group may be an anti-HBV pharmacophore.Compound 1 and Compound 2 have the best NF-κB inhibitory activity,which is equivalent to MG132.Furan compounds have the best NF-κB inhibitory activity,better than?-lactone and better than other cyclization.6,8-Diethyl substituted furan ring compounds may be a new pharmacophore for anti-inflammatory model.In addition,some of the new compounds obtained were deduced from the biogenic pathway.