Novel cytotoxic nine-membered macrocyclic polysulfur cembranoid lactones from the soft coral Sinularia sp.

One novel nine-membered macrocyclic polysulfur cembranoid lactone, sinulariaoid A (1); three new multioxygenated cembranoids, sinulariaoid B (2), sinulariaoid C (3), sinulariaoid D (4); and four known cembranoids, capilloloid (5), dihydrosinularin (6), sinularin (7), and dihydrosinuflexolide (8) were isolated from the soft coral Sinularia sp. collected off of Sanya Bay in the South China Sea. Their stereochemical structures were determined on the basis of extensive spectroscopic methods, including single crystal X-ray diffraction analysis. Sinulariaoid A (1) is the first reported nine-membered macrocyclic polysulfur cembranoid from soft coral. The cytotoxic activities of compounds 1–8 were determined in four human cancer cell lines (HepG2, HepG2/ADM, MCF-7, and MCF-7/ADM). Of these, sinulariaoid A (1) exhibited the most potent anticancer activity in vitro, and its cytotoxicity in HepG2/ADM was more potent than in the other three cell lines. Furthermore, it was found that sinulariaoid A (1) induced apoptosis, and its selective toxicity toward HepG2/ADM cells was not related to P-glycoproteins.     

Analysis of Cembranoids in Flue‐cured Tobacco by Accelerated Solvent Extraction and Gas Chromatography‐Mass Spectrometry‐Selected Ion Monitoring

An efficient and sensitive analytical method based on accelerated solvent extraction (ASE) and gas chromatography‐mass spectrometry‐selected ion monitoring (GC‐MS‐SIM) was developed and validated for analysis of cembranoids in flue‐cured tobacco leaves. Extraction efficiency of different pretreatment methods including liquid‐solid extraction (LSE), ultrasound‐assisted extraction (UAE), Soxlet extraction and accelerated solvent extraction (ASE) was compared and ASE was chosen as the optimal extraction method. During ASE procedure, effect of four parameters on extraction efficiency was considered and the experimental conditions were selected as follows: extraction solvent: dichloromethane; oven temperature: 50 °C; static time: 5 min and number of cycles: 2. Working standards of cembranoids were isolated by silica gel column chromatography and the identification was performed by mass spectrometry. Performance characteristics such as linearity, limit of detection (LOD), limit of quantitation (LOQ), precision and recovery were studied. The LOD and LOQ values were ranging from 5.0 × 10^?3 to 6.9 × 10^?3 μg/mL and 1.7 × 10^?2 to 2.3 × 10^?2 μg/mL for all analytes. At three different spiked levels, recoveries for CBT‐ol, α‐CBT‐diol and β‐CBT‐diol were 94.6%‐105.1%, 93.0%‐97.2% and 88.7%‐107.5% while the relative standard deviations (RSDs) were in the ranges of 3.9%‐6.2%, 1.8%‐8.7% and 1.7%‐6.0%, respectively. The proposed analytical methodology was successfully applied in the analysis of cembranoids in tobacco samples.     

Cembranoids from Eunicea sp. enhance insulin-producing cells proliferation

Nine new cembranoids 1–9 containing an α–methylene–γ–butyrolactone together with the known diterpenes 10–15 have been isolated from a crude extract of Eunicea sp. and their structures were established by spectroscopic methods. The proliferative effect of six of these compounds on insulin-producing cells (beta–cells) was evaluated.     

Xishaglaucumins A—J,New Cembranoids with Anti-Inflammatory Activities from the South China Sea Soft Coral Sarcophyton glaucum

Ten new cembrane-type diterpenoids,namely xishaglaucumins A—J(1—10),along with ten known related ones(11—20),have been isolated from the soft coral Sarcophyton glaucum collected off the Xisha Island in the South China Sea.Their structures were elucidated by extensive spectroscopic analysis,quantum mechanical nuclear magnetic resonance(QM-NMR)methods,X-ray diffraction analysis,chemical methods and comparison with the reported data in the literature.The absolute configuration of new compounds 1,5 and known compounds 11,12,16 and 20 were determined either by chemical methods or by X-ray diffraction analysis using Cu Kα(λ=1.5417A).In in vitro bioassay,compound 4 exhibited inhibitory effects on lipopolysaccharide(LPS)-induced inflammatory responses in BV-2 microglial cells.     

New Cembrane-Type Diterpenoids from the South China Sea Soft Coral Sinularia nanolobata

In the present study,nine new cembrane-type diterpenoids,namely ximaonanolobatins A—I(1—9),together with six related known analogs(10—15)and four known tetraprenylated alkaloids malonganenones D,E,H,and K(16—19)were isolated from the soft coral Sinularia nanolobata collected off the Ximao Island in the South China Sea.The structures of 1—9 were robustly established by a combination of detailed spectroscopic analyses,chemical reactions,quantum mechanical(QM)-NMR methods,biogenetic consideration,and the comparison with those literature data.The absolute configuration of 1 was confirmed by X-ray diffraction analysis,and the absolute configuration of 2 was determined by QM-NMR calculations and chemical transformation.In addition,the absolute configuration of 3 was determined using the modified Mosher's method.All these isolates were evaluated for their anti-inflammatory and anti-tumor activities.The results showed that only compound 15 exhibited potential anti-inflammatory effect against LPS-induced TNF-αrelease in RAW264.7 macrophages with an IC50 value of 12.6μmol/L.     

Yalongenes A and B,Two New Cembranoids with Cytoprotective Effects from the Hainan Soft Coral Sarcophyton trocheliophorum Marenzeller

Two new cembranoids, yalongenes A ( 1 ) and B ( 2 ), were isolated from the South China Sea soft coral Sarcophyton trocheliophorum Marenzeller . Their structures were elucidated by detailed spectroscopic analysis (IR, MS, and NMR) and by comparison with a related model compound. Yalongenes 1 and 2 were evaluated for their cytoprotective effects on SH‐SY5Y cell injury induced by H₂O₂ in vitro, and the result showed that only compound 1 had a significant cytoprotective activity at the concentration of 1 μM .     

Oxygenated cembranoids of the decaryiol type from the Indonesian soft coral Lobophytum sp.

Three novel cembrane diterpenoids, decaryiols B-D (5-7), characterized by a bicyclic skeleton of the decaryiol-type, have been isolated from the Indonesian soft coral Lobophytum sp., along with three known cembranoids. The stereostructures of these metabolites have been established through extensive NMR spectroscopic analysis, application of the modified Mosher method, and chemical conversion. Cembranoids obtained from Lobophytum sp. (2-7) and six semisynthetic derivatives (9-14) prepared from decaryiol were tested for cell growth inhibitory activity against three different cell lines. O-Methyl decaryiol (10) exhibited a significant and selective activity against glioma cell lines.     

Further New Bis‐cembranoids from the Hainan Soft Coral Sarcophyton tortuosum

Two new bis‐cembranoids, ximaolides F ( 1 ) and G ( 2 ), were isolated from the Hainan soft coral Sarcophyton tortuosum. The structures and relative configurations of the two new compounds were elucidated by the combination of spectroscopic methods, chemical conversion of ximaolide F ( 1 ) into ximaolide G ( 2 ), and comparison with related model compounds.     

Diterpenoids from the Hainan Soft Coral Sinularia parva

Two new cembrane diterpenes, sinulaparvalides A and B ( 1 and 2 , resp.), which contain an intriguing seven‐membered lactone moiety, along with the four known related cembranoids 3 – 6 , were isolated from the Hainan soft coral Sinularia parva. The structures of compounds 1 and 2 were established by spectroscopic methods, mainly on the basis of 2D‐NMR techniques, and were confirmed by single‐crystal X‐ray diffraction analysis. The in vitro cytotoxic activities of these compounds were tested on human colon carcinoma (HCT‐116), human promyelocytic leukemia (HL‐60), and human lung carcinoma (A‐549) tumor cell lines.