Horiolide,a novel norditerpenoid from Indian ocean soft coral of the genus Sinularia

A novel norditerpenoid, horiolide (1), has been isolated from an Indian Ocean soft coral of the genus Sinularia. The structural elucidation was achieved by a study of its spectral characteristics. This compound is structurally characterized by a new carbon skeleton having one six-membered cyclohexane ring bearing an isopropylene moiety, a carbonyl group, and one seven-membered ring attached to a five-membered lactone moiety.     

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.     

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.     

Oxygenated cembranoids from a Formosan soft coral Sinularia gibberosa

Chemical investigation of a Formosan soft coral, Sinularia gibberosa, has led to the isolation of eight oxygenated cembranoids, 1- 8, including seven new compounds, gibberosenes A-G ( 2- 8). None of these compounds were found to be cytotoxic toward a limited panel of cancer cell lines. Compound 1 significantly inhibited the accumulation of the pro-inflammatory COX-2 protein of the LPS-stimulated RAW264.7 macrophage cells.     

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.     

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.     

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.     

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.     

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.     

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.     

Scabrolides E-G, three new norditerpenoids from the soft coral Sinularia scabra

Three new norditerpenoids, scabrolides E-G (1-3), and dissectolide A (4) have been isolated from the organic extract of a Taiwanese soft coral Sinularia scabra. The structures of 1-3 were determined on the basis of extensive spectroscopic analyses and by comparison of their spectral data with those of the known related metabolites. Metabolite 1 was found to exhibit significant cytotoxicity against the growth of Hepa59T/VGH and KB cell lines.     

A cytotoxic 5alpha,8alpha-epidioxysterol from a soft coral Sinularia species

A new sterol, (22R,23R,24R)-5alpha,8alpha-epidioxy-22, 23-methylene-24-methylcholest-6-en-3beta-ol (1), as well as two known sterols, numersterol A (2) and pregnenolone (3), have been isolated from a soft coral Sinularia sp. The structure of metabolite 1 was determined by spectral analysis. Cytotoxicity of sterols 1-3 toward various cancer cell lines is also reported.     

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.     

Sinulaflexiolides A-K, cembrane-type diterpenoids from the chinese soft coral Sinularia flexibilis

A bioassay-guided fractionation and chemical examination of the soft coral Sinularia flexibilis resulted in the isolation and characterization of sinulaflexiolides A-K (1-11), along with sinulariolone (12), 5-dehydrosinularolide (13), capillolide (14), sinulariolide (15), 5,8-epoxy-9-acetoxysinulariolide (16), flexibilide (17), dihydroflexibilide (18), and the enantiomer of 14-deoxycrassin (19). Their structures were determined on the basis of extensive spectroscopic (IR, MS, 2D NMR) data analysis and by comparison with spectroscopic data reported in the literature. Sinulaflexiolides D and E showed selective inhibitory activity against the gastric gland carcinoma cell line BGC-823 at 8.5 and 0.12 microM, respectively.     

Scabrolides A-D,four new norditerpenoids isolated from the soft coral Sinularia scabra

Four new norditerpenoids, scabrolides A-D (1-4), along with four known ones, 5-8, have been isolated from the dichloromethane extract of the Taiwanese soft coral Sinularia scabra. The structures of 1-4 were elucidated on the basis of extensive spectroscopic analyses, while the relative configurations were determined by the NOESY experiments. The epimeric metabolites 6 and 7 have been shown to exhibit strong cytotoxic activity against KB and Hepa59T/VGH cancer cell lines.     

A cytotoxic lobane diterpene from the formosan soft coral Sinularia inelegans

A new cytotoxic lobane diterpene, ineleganene (1), was isolated from the Formosan soft coral Sinularia inelegans. The structure of compound 1 was determined by 1D and 2D spectral analysis.     

A C-3 methylated isocembranoid and 10-oxocembranoids from a formosan soft coral, Sinularia grandilobata

Five new cembranoids, designated grandilobatins A-E (1- 5), were isolated from the soft coral Sinularia grandilobata. Grandilobatin C (3) was found to have a novel skeleton with the C-4 methyl group of the normal cembranoid rearranged to C-3, while the other metabolites were identified as new 10-oxocembranoids. Metabolite 4 has weak cytotoxicity toward MDA-MB-23 human breast tumor cells. Also, 4 significantly inhibited the accumulation of the pro-inflammatory iNOS protein of LPS-stimulated RAW264.7 macrophage cells at 50 microM.     

Sinulodurins A and B, antiproliferative and anti-invasive diterpenes from the soft coral Sinularia dura

Two new diterpenes, sinulodurin A (1) and sinulodurin B (2), along with two known sterols, 24 S-methyl cholesterol and 24-methylene cholesterol, were isolated from the Palau soft coral Sinularia dura. The structures of the new metabolites were determined on the basis of spectroscopic methods and by comparison of NMR data with those of related metabolites. Sinulodurin A (1) and sinulodurin B (2) showed antiproliferative activity against highly malignant +SA mammary epithelial cells with an IC 50 range of 20-30 microM. They also displayed anti-invasive activity against human highly metastatic prostate cancer PC-3M-CT+ cells in the spheroid disaggregation assay. Furthermore, the antimicrobial activities of the isolates were tested.     

(Z)-sarcodictyin A,a new highly cytotoxic diterpenoid from the soft coral Bellonella albiflora

A new cytotoxic diterpene, (Z)-sarcodictyin A, was isolated from the Japanese soft coral Bellonella albiflora.(1) Its structure was elucidated on the basis of 1D and 2D NMR analysis and chemical degradation. (Z)-Sarcodictyin A showed strong cytotoxicity against HeLa human cervix cells.