Oxygenated terpenoids from a formosan soft coral Sinularia gibberosa

Three new oxygenated sesquiterpenoids, gibberodione (1), peroxygibberol (2), and sinugibberodiol (3), along with sarcophytol L (4) were isolated from a Formosan soft coral, Sinularia gibberosa. The structures of the new metabolites were determined on the basis of extensive spectroscopic analyses and by comparison of NMR data with those of related metabolites. Metabolites 2 and 4 were found to exhibit moderate cytotoxicity toward a human liver carcinoma cell line.     

Polyoxygenated sterols from the Formosan soft coral Sinularia gibberosa

Chemical investigation on the dichloromethane-soluble fraction from the EtOH extract of Sinularia gibberosa Tixier-Durivault has led to the isolation of three new polyoxygenated sterols, gibberoketosterols B (1) and C (2) and gibberoepoxysterol (3), along with two known steroids, gibberoketosterol (4) and 24-methylenecholest-5-en-3beta-ol (5). These cholestane-type sterols possessing a 22,24(28)-conjugated diene (1 and 2) in the side chain or a 5alpha,6alpha-epoxide in the B-ring (3) were isolated for the first time from marine sources. Compound 4 showed significant inhibition against the up-regulation of the pro-inflammatory iNOS and COX-2 proteins of LPS-stimulated RAW264.7 macrophage cells, while 1 was found to be inactive. The cytotoxicity of 1-4 toward a limited panel of cancer cell lines is also reported.     

Cytotoxic cembranoid diterpenes from a soft coral Sinularia gibberosa

Five new alpha-methylene-gamma-lactone-bearing cembranoid diterpenes, sinularolides A-E (1-5), along with 10 known cembranoids, were isolated from the soft coral Sinularia gibberosa. Their structures were determined by extensive spectroscopic (IR, MS, 2D NMR) data analysis. Compounds 2-5 showed moderate activity against selected tumor cell lines.     

Anti-inflammatory cembranoids from the soft corals Sinularia querciformis and Sinularia granosa

Four new cembranoids, querciformolides A-D (1-4), along with two known cembranoids, 7 and 8, have been isolated from the soft coral Sinularia querciformis. Furthermore, chemical investigation of Sinularia granosa has afforded three new cembranoids, querciformolide B (2) and granosolides A (5) and B (6). The structures of the new metabolites were elucidated on the basis of extensive spectroscopic methods, and that of 2 was further confirmed by X-ray diffraction analysis. The absolute configurations of 1 and 2 were determined by a modified Mosher's method. Among these metabolites, 2-6 are rarely found cembranoids possessing a tetrahydrofuran moiety with a 4,7-ether linkage; in addition, 1 is the first epsilon-lactone cembrane found that possesses a tetrahydropyran moiety with a 4,8-ether linkage. None of these compounds were found to be cytotoxic toward a limited panel of cancer cell lines. However, compounds 3, 7, and 8 significantly inhibited the accumulation of the pro-inflammatory iNOS and COX-2 proteins in LPS-stimulated RAW264.7 macrophage cells.     

Meroditerpenoids from a Formosan soft coral Nephthea chabrolii

Eight new meroditerpenoid-related metabolites, including one naphthoquinone derivative, chabrolonaphthoquinone B (1), four tetraprenyltoluquinone-related compounds, chabrolobenzoquinones E-H (2-5), and three tetraprenyltoluquinol-related metabolites, chabrolohydroxybenzoquinones E-G (6-8), were isolated from the organic extract of a Taiwanese soft coral Nephthea chabrolii. The structures of 1-8 were elucidated on the basis of extensive spectroscopic analysis and by comparison of the data with those of the related metabolites. Cytotoxic activity of metabolites 1-3 and 5-8 against a limited panel of cancer cell lines is also described.     

Cytotoxic diterpenoids from the soft coral Sinularia microclavata

The soft coral Sinularia microclavata collected from the bay of Sanya, Hainan Island, China, yielded a new diterpenoid, microclavatin (1), and a known cembranolide, capillolide (2). The structure of compound 1 was determined on the basis of spectroscopic methods and X-ray single-crystal diffraction analysis. Microclavatin (1) showed cytotoxic activities against tumor cell lines KB and MCF with IC50 values of 5.0 and 20.0 microg/mL, respectively, and capillolide (2) showed potent cytotoxic activity against tumor cell lines (A-549) with an IC50 value of 0.5 microg/mL.     

Cytotoxic diterpenoids from the hybrid soft coral Sinularia maxima x Sinularia polydactyla

Chemical investigation of the hybrid soft coral Sinularia maxima x Sinularia polydactyla yielded four new cembranolide diterpenes (1-4), the norcembranoid 5-episinuleptolide (5), and two known sesquiterpenes. The structures and configurations of the new compounds were determined by spectroscopic techniques and comparison of NMR data with those of related metabolites. Compound 3 shows strong cytotoxicity on the breast cancer SK-BR3 cell line and cervix cancer HeLa and HeLa-Apl cell lines with GI(50) values of 0.039, 0.48, and 0.56 microM, respectively.     

Capnellenes from the Formosan soft coral Capnella imbricata

Three anti-inflammatory sesquiterpenes, Delta (9(12))-capnellene-8beta,10alpha-diol ( 1), 8alpha-acetoxy-Delta (9(12))-capnellene-10alpha-ol ( 2), and Delta (9(12))-capnellene-10alpha-ol-8-one ( 3), five new sesquiterpenes, Delta (9(12))-capnellene-8beta,15-diol ( 4), Delta (9(12))-capnellene-8beta,10alpha,13-triol ( 5), Delta (9(10))-capnellene-12-ol-8-one ( 6), 8beta,10alpha-diacetoxy-Delta (9(12))-capnellene ( 7), and 8beta-acetoxy-Delta (9(12))-capnellene ( 8), and a known sesquiterpene, Delta (9(12))-capnellene-8beta-ol ( 9), were isolated from the acetone/methylene chloride extracts of the Formosan soft coral Capnella imbricata. The structures of these compounds were elucidated by extensive spectroscopic analysis.     

Cytotoxic and anti-inflammatory cembranoids from the soft coral Lobophytum crassum

Five new cembranoids, namely, crassumolides A and B and D-F (1 and 2 and 4-6), along with four known metabolites, 7-10, were isolated from the soft coral Lobophytum crassum. Crassumolide C (3) was isolated for the first time from a natural source. The structures of these compounds were elucidated by extensive spectroscopic analysis and comparison of the NMR data with those of known analogues. The absolute stereochemistry of 1 was determined using the modified Mosher's method. Chemical transformation of 7 into the corresponding methyl ester 3 revealed the absolute stereochemistry of 3. Compounds 1, 3, and 7 were cytotoxic toward Ca9-22 cancer cells, and 10 was broadly cytotoxic toward all six test cancer cell lines used. Compounds 1, 3, 7, and 10 were found to inhibit the accumulation of the pro-inflammatory proteins iNOS and COX-2 at 10 μM.     

Seco-sethukarailin,a novel diterpenoid from the soft coral Sinularia dissecta

Seco-sethukarailin (1), a novel diterpenoid, has been isolated along with known sesquiterpenes Delta(9(15))africanene, beta-elemene, african-1-ene, 6R,7R-6,7-epoxycaryophyll-3(15)-ene, and known diterpenoids sethukarailin and isomandapamate, from the soft coral Sinularia dissecta collected from Mandapam Coast, South India. The structure of the novel diterpenoid seco-sethukarailin (1) was characterized by interpretation of spectral data.     

New beta-caryophyllene-derived terpenoids from the soft coral Sinularia nanolobata

Two new norsesquiterpenoids, nanonorcaryophyllenes A (1) and B (2), two new diterpenoids, nanolobatins A (3) and B (4), and a novel norditerpenoid, nanolobatin C (5), were isolated from the n-hexane extract of the Taiwanese soft coral Sinularia nanolobata. Also, two new furanone derivatives, 6 and 7, were isolated for the first time from natural sources. The structures of 1-5 were elucidated on the basis of extensive spectroscopic analyses and by comparison of the spectral data with those of the related metabolites. Nanonorcaryophyllenes A (1) and B (2) were characterized as 13-norcaryophyllenes that lack a methyl group at C-11, while nanolobatin C (5) represents the first example of a xeniaphyllane-based 17-norditerpenoid. The cytotoxicity of 1-6 against the growth of a limited panel of cancer cell lines is also described.     

A new cembranolide from the soft coral Sinularia capillosa

A new cembranolide, capillolide (1), and three known cembranolides were isolated from the soft coral Sinularia capillosa collected from the South China Sea. Their structures and the relative stereochemistry of 1 were deduced on the basis of spectroscopic methods.     

Further casbane-type diterpenes from the soft coral Sinularia depressa

AIM： To study the minor diterpenes from the soft coral Sinularia depressa. METHOD： The chemical constituents were isolated and purified by various chromatographic techniques, and the chemical structures, including absolute configuration, were established on the basis of detailed analysis of spectroscopic data and by literature comparison with the data of related known compounds. RESULTS： A new casbane-type diterpene, 2-epi-10-hydroxydepressin（1）, was isolated and identified. CONCLUSION： Compound 1 is a new casbane-type diterpene.     

Cytotoxic terpenoids from the Formosan soft coral Nephthea brassica

Two new cytotoxic cembranoid diterpenes, brassicolide (1) and brassicolide acetate (2); a new cytotoxic sesquiterpene, (-)-4alpha-O-acetyl-selin-11-en (3); and six cytotoxic terpenoids, (-)-selin-11-en-4alpha-ol (4), 2-hydroxynephthenol (5), nephthenol (6), cembrene A (7), epoxycembrene A (8), and (-)-beta-elemene (9), have been isolated from the Formosan soft coral Nephthea brassica. The structures of compounds 1-9 were determined by spectral, chemical, and X-ray crystallographic analysis.     

Nardosinane sesquiterpenoids from the Formosan soft coral Lemnalia flava

Four new nardosinane-type sesquiterpenoids, flavalins A-D (1-4), have been isolated from the Formosan soft coral Lemnalia flava. The structures of the new metabolites were determined by extensive spectroscopic analysis, and the structure of 2 was confirmed by X-ray diffraction analysis. A plausible biosynthetic pathway to 1 and 2 is proposed. Compound 1 was found to display dose-dependent inhibition of iNOS protein expression, and 1 and 2 were shown to possess significant neuroprotective activity.     

A new spermatostatic glycoside from the soft coral Sinularia crispa

The steroid glycoside 1 has been isolated from the Sri Lankan soft coral Sinularia crispa. The structure has been determined by spectroscopic (1H and 13C nmr) techniques. Glycoside 1 showed spermatostatic activity on rat cauda epididymal spermatozoa.     

Manaarenolides A-I, diterpenoids from the soft coral Sinularia manaarensis

Nine cembrane-type diterpenoids, manaarenolides A-I (1-9), along with two known cembranolides, 10 and 11, have been isolated from the ethyl acetate extract of the Taiwanese soft coral Sinularia manaarensis. Among these metabolites, diterpenes (1, 2, 5, and 6) were discovered for the first time as the hydroperoxycembranolides possessing a delta-lactone ring. The 13-epimeric metabolites 7 and 8 have been shown to exhibit moderate cytotoxic activity against Hepa59T/VGH, KB, Hela, and Med cancer cell lines. The biosynthetic relationship between these new metabolites and 10 and 11 is also discussed.     

New cadinene sesquiterpenoids from the Formosan soft coral Xenia puerto-galerae

Six new cadinene sesquiterpenoids, xenitorins A-F (1-6), were isolated from the methylene chloride solubles of the Formosan soft coral Xenia puerto-galerae. The structures were elucidated by 1D and 2D NMR spectral analysis, and their cytotoxicity against selected cancer cells was measured in vitro.     

Sesquiterpenoids and norsesquiterpenoids from the Formosan soft coral Lemnalia laevis

Eight new nornardosinane sequiterpenoids, laevinols A-H (1-8), a new neolemnane sesquiterpenoid, laevinone A (9), and the previously known 6beta-acetyl-4beta,5beta-dimethyl-1(10)alpha-epoxy-2beta-hydroxy-7-oxodecalin (10) and 11,12-dihydroxy-6,10-eremophiladiene (11) were isolated from the methylene chloride solubles of the Formosan soft coral Lemnalia laevis. Their structures were elucidated by extensive spectroscopic analysis, and their cytotoxicity against selected cancer cells was measured in vitro.     

Crassolides A-F, cembranoids with a trans-fused lactone from the soft coral Sarcophyton crassocaule

Six new polyoxygenated cembrane-based diterpenoids possessing a trans-fused alpha-methylene-gamma-lactone, crassocolides A-F (1-6), have been isolated along with the known compound 7 from the ethyl acetate extract of a Taiwanese soft coral, Sarcophyton crassocaule. The structures of 1-6 have been established by detailed spectroscopic analysis, including 2D NMR (1H-1H COSY, HMQC, HMBC, and NOESY) spectroscopy, while their absolute configurations were determined using a modified Mosher's method for 1. The structure of 5 was further proven by X-ray diffraction analysis. The full assignment of NMR data of 7 is reported herein for the first time. The cytotoxicity of crassocolides 1-4, 6, and 7 against a limited panel of cancer cells was also determined.