| The marine sponges are considered to be primitive organisms, with relative simple internal organization. The constituent cells of marine sponges form neither tissue layer nor organs, however, it dose perform specialized functions depending on the location within the sponge. Marine sponges have a very strong pumping capability of filtering a large volume of water through its tissues for food and oxygen, it is thus not surprising that marine sponges can live in a poor nutrient environment and many marine sponges contain symbiotic micro-organisms. Marine sponges occur in all oceans and have a wide distribution from tropical to temperate to arctic regions. They frequently produce large quantities of secondary metabolites to deter potential predators and to inhibit the growth of fouling organisms, and thus become one of important sources of bioactive marine natural products.In the process of searching for bioactive compounds, we have successively investigated three species of marine sponges collected off the Lingshui Bay, Hainan Province, China. By repeatedly chromatography on gel Sephadex LH-20 and silica gel columns, as well as purification by RP-HPLC, 51 compounds were obtained from the acetone extracts of the three species, including 24 sesquiterpens, 22 sesterterpenes, 1 triterpene, 3 indole compounds and 1 sterol. The structures of the compounds were elucidated on the basis of extensive spectroscopic analysis and comparison with reported data, one of which was secured by X-ray diffraction analysis experiment. Ten of the metabolites were identified as new compounds, and three were isolated from the natural source for the first time. The interesting fact is that the new spiro-sesquiterpene could convert to its dimer in dauterated chloroform solution under room temperature, which was further confirmed by X-ray diffraction analysis.All the compounds were subjected to a series of bio-screening experiments. Heteronemin was found to be cytotoxic against A-549, HL-60, HELA and BEL-7402 with IC50 of 2.31×10-10M, 1.92×10-7M, 2.42×10-6M and 1.72×10-8M, respectively. Hyrtiosal, 12, 18-diepiscalaradial, and scalarafuran were found to show inhibitory activity against PTP1B with IC50 of 6.04×10-5M, 3.16×10-5M, and 5.42×10-5M, respectively.
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