| Backgrounds and Objectives:Marine sponges belong to Porifera. They are the most primitive multicellular animals. Generally, they are attached on the coral reefs in the crowded living space, using the old way of chemical type to transfer information. In long-term natural competition, many bioactive secondary metabolites were found in marine sponge. These bioactive secondary metabolites are important to marine drugs. Therefore, sponge become an international research hotspot. There are3drugs derived from marine sponge in7marine drugs are approved by FDA and EMA. As part of project "Searching for bioactive metabolites from the South China Sea marine organisms", in order to obtain lead with biological activity, researches have been carried on the sponge Leucandra sp. which was collected for the first time in China.Methods and results:39compounds (A1-A39) were isolated from the sponge Leucandra sp. by solvent extraction,1H NMR guide-isolation, and chromatography methods including VLC, MPLC, HPLC on silica gel, ODS C-18and Sephadex LH-20. These compounds were identified by1H NMR,13C NMR,1H-1H COSY, HSQC, HMBC, NOESY, MS and circular dichroism as:leucandraoid A (Al), leucandraoid B (A2),7-hydroxy-3,4-Dimethylenedioxy phenylacetic acid (A3),7-methy1-7-hydroxy-3,4-Dimethylenedioxy phenylacetic acid (A4),3,4-Methylene dioxyacetophenone (A5),3,4-Methylene-dioxy-benzophenone methyl formate (A6),3,4-Methylenedioxy-phenylacetamide (A7), Piperonyl alcohol (A8), cholestan-3β,5α,6β-triol (A9), ergosta-7,22-dien-3β,5α,3β-triol (A10), Cholesterol (All),3β-hydroxycholest-5,7,9(11),22-tetraene (A12), β-hydroxycholest-5,7,22-triene (A13), ergosterol (A14),3β-hydraoxyergosta-5,7,9(11),22-tetraene (A15),3β-hydroxysitost-5,7,22-triene (A16), n-hexadecoic acid (A17), Triple Pressed Stearic Acid (A18), Thymine (A19), Thymidine (A20), Uracil (A21), methyl (2Z,6R,8R,9E)-3,6-epoxy-4,6,8-triethyl2,4,9dodecatrienoate (A22),1-(2-deoxy-β-D-Ribofuranosyl) uracil (A23),1,3,7-Trimethyl-xanthine (A24), Ethyl4-hydroxybenzoate (A25), bis(2-ethylhexyl) phthalate (A26),3β-hydroxy-(22E,24R)-24-ethylcholesta-5,8,22-trien-7-one (A27), Cholesta-5-ene-3p,7a-diol (A28), Butylparaben (A29), Octylparaben (A30), Decyl hydroxybenzoate (A31), Methyldecylparaben (A32), Cholesta-5-ene-3β,7a-diol (A33),2-Methyl-13-icosenoic acid methyl ester (A34),2-methyl-13-icosenoic acid pyrrolidide (A35),2-methyl-13-icosenoic acid dimethyl disulfide (A36),5α(H)-cholestan-3-one (A37),(3β)-stigmast-7-en-3-ol (A38),(3β)-stigmast-5-en-3-ol (A39). Among them compounds A1and A2were new compounds, Compounds A1showed biological activity against MDA-MB-231in vitro.In this work, by using "multi-stage IR macroscopical fingerprint analysis method", the three-stage technology including infrared spectrum identification, the second derivative spectra, two-dimensional infrared correlation spectroscopy were used to describe the characterization of all the collected sponges. This method was also used to characterize the sponges which were collected at the different time but in the same area and at the same time in the same area but different parts of the same kind of sponge. This work is aimed to explore and construct a method to characterize the differences between the two similar sponges.Conclusion:This dissertation describes the details of isolation and structure elucidation of metabolites from the marine sponge Leucandra sp. and IR method is used to describe the characterization. By the study of Leucandra sp., vairous kinds of chemical structures were discovered except the sterol and fatty acids. This enriches our understanding of calcareous sponge. The method using IR to characterize the sponges which were collected at the different time but in the same area and at the same time in the same area but different parts of the same kind of sponge led us to explore and construct a a more simple and more objective method to characterize the differences between the two similar sponges. |
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