Studies On Chemical Constituents And Bioactivities Of The Marine Sponge Theonella Swinhoei From The Xisha Islands

Marine invertebrates possessing massive structurally unique secondary metabolites with various bioactivities for its diversity of species,specificity of metabolic pathways,complexity of environment,and multiplicity of the symbiosis,have already been a rich resource of marine bioactive compounds with high efficiency and low toxicity.Sponge provided 25%of bioactive marine natural products,among which several compounds with the prospect of clinical applications.The development of marine natural products therefore to be hot research area of discovery of drugs for years.In this study,systematic investigation of compounds isolation,structural elucidation and bioassay of focused on chemical diversity and bioactivity of marine sponge Theonella swinhoei collected from Woody Island of the South China Sea was conducted.Twenty compounds?1-21?were isolated and purified from the petroleum ether fraction by using solvent extraction and current chromatographic methods including VLC,MPLC,HPLC,TLC on silica gel,ODS and Sephadex LH-20.The structure of these compunds,including 15 steroids,2 diterpenoids,1 sesquiterpene,2amides and 1 alkaloid,were elucidated by ¹H-NMR?¹³C-NMR?¹H-¹HCOSY?HSQC?HMBC?NOESY and HRESIMS as:conicasterol L?1?,dehydroswinhosterol B?2?,conicasterol M?3?,conicasterol N?4?,5-?2-hydroxy-4-?2,6,6-trimethyl-3-oxocyclohex-1-en-1-yl?butan-2-yl?dihydrofuran-2?3H?-one?5?,conicasterol?6?,conicasterol G?7?,swinhosterol B?8?,swinhoeisterol A?9?,15-oxoconicasterol?10?,9?-15-oxoconicasterol?11?,conicasterol E?12?,conicasterol F?13?,cholest-7-ene-3?,5?,6?-triol?14?,ergosta-7,22-diene-3?,5?,6?-triol?15?,25-norcycloartane-3?,6?,16?,24-tetraol?16?,sinuflexibilin D?17?,14-deoxycrassin?18?,N-?2-phenylethyl?-?9Z?-tetradecanamide?19?,N-?2-phenylethyl?-tetradecanamide?20?,7,8-dimethyl-isoalloxazine?21?.Compounds 1⁵ are new compounds and Compounds 14²0 are reported for the first time in the genus Theonella.The cytotoxicity of all these compounds have been evaluated with the CCK-8method.Compounds 3,10,and 11 showed moderate cytotoxicity to U937 cell with IC₅₀ value of 8.8,2.0,3.2?M,and PC9 cell with IC₅₀ value of 6.9,9.7,1.6?M.Compounds 3 and 11 also showed moderate cytotoxicity to MCF-7 cell with IC₅₀value of 5.4,5.2?MOur study focused on the secondary metabolites of marine sponge Theonella swinhoei and their bioactivities.The discovery of new 4-methylene steroids,which share both species characteristics and individual specificity of sponge from the South China Sea,definitely enriched the library of natural products from sponge Theonella swinhoei.The results revealed the biodiversity and chemistry diversity of marine organism of Xisha Islands of the South China Sea,which is considered to be a potential resource of pharmaceutical agents.