Studies On The Bioactive Constituents Of Acanthella Cavernosa And Sinularia Sp.

Marine invertebrates are assumed to have unique chemical defense mechanisms,and a lot of significant anti-fouling secondary metabolites have been isolated.Marine nature products become an important source of antifoulant.In this paper,a sponge and a soft coral are investgated,led to the isolation and determination of 53 metabolites.Among these compounds,21 of them were new compounds.Their antifouling,cytotoxic and antifungal activities have been evaluated.The marine sponge Acanthella cavernosa belonged to order Halichondrida and family Axinellidae.The fresh sponge of A.cavernosa was exhaustively extracted with acetone at room temperature,followed by sequential solvent partitioning between organic and aqueous phases to obtain petroleum ether,CH2Cl2 and n-butyl alcohol layers.Petroleum ether and CH2Cl2 layers displayed significant antifouling activity against Balanus amphitrite larvae with EC50 value of 15.84 and 10.76 μm.42 compounds were obtained by chromatographic methods including VLC,LPLC,MPLC,HPLC on silica gel,ODS C-18 and Sephadex LH-20,they were identified by 1H-NMR,13C-NMR,HSQC,HMBC,1H-1H COSY,NOESY(ROESY)and MS spectrums as:kalihinol M(A1),kalihinol N(A2),kalihinol O(A3),kalihinol P(A4),kalihinol Q(A5),kalihinol R(A6),kalihinol S(A7),kalihinol T(A8),cavernene A(A9),cavernene B(A10),cavernene C(A11),cavernene D(A12),kalihinene E(A13),kalihinene F(A14),kalihinene G(A15),kalihinene H(A16),kalihipyran C(A17),kalihihepene A(A18),kalihihepene B(A19),kalihinol E(A20),kalihinol A(A21),10-epi-kalihinol X(A22),10-epi-kalihinol I(A23),10β-formamidokalihinol-A(A24),10β-formamido-5β-isothiocyanatokalihinol-A(A25),10-isothiocyanatokalihinol-G(A26),15-formamido-kalihinene(A27),10-formamido-kalihinene(A28),kalihinene X(A29),kalihinene Y(A30),kalihinene Z(A31),kalihipyran A(A32),2(5H)-furanone-3,5-diethyl-5-(2-ethyl-3-hexen-1-yl)(A33),methyl(2Z,6R,8S)-4,6-diethyl-3,6-epoxy-8-methyldodeca-2,4-dienoate(A34),methyl(2Z,6R,8R,9E)-3,6-epoxy-4,6,8-triethyl-2,4,9-dodecatrienoate(A35),methyl(2Z,6R,8S)-3,6-epoxy-4,6,8-triethyldodeca-2,4-dienoate(A36),1H-indole-3-carboxylic acid methyl ester(A37),1H-indole-3-carboxylic acid(A38),3-buten-2-one,4-(2,3,6-trimethylphenyl)-(3E)(A39),aristolone(A40),5α,8α-epidioxy-(22E,24R)-erost-6,22-dien-3β-ol(A41),ergosterol(A42).Among these compounds,A1～A19 were new.The absolute structures of A1-A8,A13 and A20-A25 were determined by single crystal X-ray diffraction and CD spectrum.The antifouling,cytotoxic and antifungal activities were evaluated,compounds A3-A8 and A20-A25 showed significant antifouling activity.The plausible biogenetic pathways of the kalihinenes have been postulated.Kalihinenes displayed moderate cytotoxic activities against HCT-116,CT26,A549,H1299,PC3,HeLa,QGY-7701 and MDA-MB-231,and showed weak and none antifungal activities against Candida albicans,Candida parapsilosis,Candida glabrata,Cryptococcus neoformans,Microsporum gypseum,Trichophyton rubrum,and Aspergillus fumigates.The soft coral of genus Sinularia SP.belonged to order Alcyonacea and family Alcyoniidae.The fresh soft coral of genus Sinularia SP.was exhaustively extracted with CH2C12/MeOH(1:1)at room temperature,followed by sequential solvent partitioning between organic and aqueous phases to obtain petroleum ether,CH2Cl2 and n-butyl alcohol layers.11 compounds were obtained by chromatographic methods including VLC,LPLC,MPLC,HPLC on silica gel,ODS C-18 and Sephadex LH-20 from CH2Cl2 layers,they were identified by ’H-NMR,13C-NMR,HSQC,HMBC,1H-1H COSY,NOESY(ROESY)and MS spectrums as:5-episinuleptolide(B1),sinuleptolide(B2),scabrolide D(B3),norcembrenolide 2(B4),5-epinorcembene(B5),sinulochmidin D(B6),norcembrenolide 6(B7),norcembrenolide 7(B8),yonarolide(B9),horiolide(B10),a-cadinol(B11),B7 and B8 were new compounds.The absolute structure of B1 was determined by single crystal X-ray diffraction.The cytotoxic activity of the diterpenes was evaluated.This dissertation describes the details of isolation and structure elucidation of new and bioactive compounds from marine sponge and soft coral collected from Paracel Islands of South China Sea by bioassay,UV and NMR-guided separation.The results reveal the biodiversity and chemistry diversity of marine organism of Paracel Islands of the South China Sea,which is proved to be a potential resource of antifouling agents.