Nardosinane sesquiterpenoids from the formosan soft coral Nephthea elongata

Seven new nardosinane sesquiterpenoids, elongatols A-G (1-7) were isolated from the methylene chloride solubles of the Formosan soft coral Nephthea elongata. Their structures were elucidated by extensive spectroscopic analysis and their cytotoxicity against selected cancer cells was measured in vitro.     

Prenylbicyclogermacrane diterpenoids from the formosan soft coral Nephthea elongata

Seven new prenylbicyclogermacrane diterpenoids, pacificins K--Q (1--7), were isolated from the methylene chloride solubles of the Formosan soft coral Nephthea elongata. Their structures were elucidated by extensive spectroscopic analysis and their cytotoxicity against selected cancer cells was measured in vitro.     

软珊瑚Nephthea sp.次级代谢产物生物碱的研究

首次从白蕙软珊瑚Nephthea sp.中分离得到含硒元素的已知化合物二苯基硒醚(1),同时分离得到已知化合物生物碱(2-7)通过对其质谱、一维和二维核磁共振谱结构信息进行分析,确定其化学结构.     

Neolemnane-type sesquiterpenoids from a formosan soft coral Paralemnalia thyrsoides

Six new sesquiterpenoids, paralemnolins D-I (1-6), have been isolated from the EtOAc extract of the soft coral Paralemnalia thyrsoides. The structures of these metabolites were determined by extensive spectroscopic analysis and by comparison of their spectral data with those of related metabolites. The absolute stereochemistry of these metabolites was established by application of the Mosher's method on 1 and on the basis of the absolute structures of other related compounds previously isolated from the soft corals of the genera Paralemnalia and Lemnalia. Cytotoxicity of these metabolites toward a limited panel of cancer cell lines also is reported.     

Glycolipids from the formosan soft coral Lobophytum crassum

Three glycolipids (1--3), possessing a sugar moiety at C-2 of glycerol ether, have been isolated from the Formosan soft coral Lobophytum crassum. Their structures were elucidated by spectroscopic methods, particularly in 1D- and 2D-NMR experiments. The absolute configurations on the sugar portion and lipid aglycon of 1--3 were determined by methanolysis, chemical transformation and the application of Mosher's method on 1 and 3. Compounds 1--3 exhibited weak cytotoxic activities.     

Xeniaphyllane-derived terpenoids from the formosan soft coral Sinularia gibberosa

New xeniaphyllane-derived metabolites (1-7) were isolated from the EtOAc extract of the Formosan soft coral Sinularia gibberosa. The structures and relative configurations of these compounds were elucidated on the basis of extensive spectroscopic analysis (including 2D NMR) and by comparison of their spectral data with those of related compounds. In vitro cytotoxic evaluation of the above metabolites towards a limited panel of cancer cell lines is also described.     

New cytotoxic constituents from the Red Sea soft coral Nephthea sp.

Nephthea are soft coral species rich in sesquiterpenoids and steroids. An organic extract of Nephthea sp. resulted in the isolation of a new steroid (1), as well as several previously reported metabolites (2–9). Structures were elucidated by employing NMR and HR-EI-MS analyses. The total extract, fractions and purified compounds exhibited differential cytotoxicity against the breast cancer MCF-7 cell line.     

New cembranolide analogues from the formosan soft coral Sinularia flexibilis and their cytotoxicity

Using a bioactivity-guided fractionation procedure, five cembranolides, 11-epi-sinulariolide acetate (1), 11-dehydrosinulariolide (2), sinulariolide (3), dihydrosinularin (4), and 3,4:8,11-bisepoxy-7-acetoxycembra-15(17)-en-1,12-olide (5), along with two nucleosides, 2'-deoxyadenosine and thymidine, were isolated from the Formosan soft coral Sinularia flexibilis. Moreover, 7,8-epoxy-11-epi-sinulariolide acetate (1a), 11-sinulariolide acetate (3a), dihydrosinulariolide (3b), 3,4:8,11-bisepoxy-7-hydroxycembra-15(17)-en-1,12-olide (3c), 11-acetoxyl-15(17)-dihydrosinulariolide (3d), 7,8-epoxy-11-sinulariolide acetate (3e), and 3,4:8,11-bisepoxy-7-hydroxycembra-15(17)-dihydro-1,12-olide (3f) were derived from compounds 1 and 3, respectively. These structures were deduced on the basis of physical and chemical evidence. Among them, 1a, 3d, 3e, and 3f are new cembranolide analogues. The structure of compound 1 was further confirmed by X-ray analysis. In addition, the isolated cembranolides and the analogues under went a cytotoxicity assay, and the structure-activity relationship (SAR) of these compounds was studied.     

Polyhydroxylated steroids and other constituents of the soft coral Nephthea chabroli

Polyhydroxylated steroids and other metabolites were isolated from the soft coral Nephthea chabroli collected in South China Sea. The structures of two new compounds were determined to be 24-methylcholesta-9(11), 24(28)-diene-3beta,12alpha,19-triol and 4alpha-methyl-3beta,14beta-dihydroxy-5alpha-ergost-24(28)-en-23-one on the basis of spectroscopic analysis. Cytotoxic activities of the polyhydroxylated sterols were evaluated on prostate carcinoma LNCaP cell line.     

Xenibellols A and B, new diterpenoids from the formosan soft coral Xenia umbellata

Xenibellols A (1) and B (2), possessing an unprecedented diterpenoid skeleton, were isolated from the soft coral Xenia umbellata. The structures of xenibellols A and B were established by extensive analysis of spectroscopic data.     

Synthesis of cytotoxic spermidine metabolites from the soft coral

Two unusual cytotoxic agents, the first spermidine derivatives from marine organisms, have been synthesized directly from the parent polyamine using new methodology.     

New prostanoids from soft coral

Four new anti-tumor active prostanoids, named claviridenone-a (3), claviridenone-b (4). claviridenone-c (5), and claviridenone-d (6), as well as 20-acetoxy-claviridenone-b (7) and 20-acetoxy-claviridenone-c (8), have been isolated from the Okinawan soft coral (stolonifer) Clavularia viridis Quoy and Gaimard (Stolonifera, Clavulariidae). The absolute stereostructures of these six prostanoids have been elucidated on the basis of chemical and physicochemical evidence which includes the application of the CD exciton chirality method to their various benzoyl derivatives having benzoate and conjugated diene chromophores. Claviridenones possess a characteristic cross-conjugated dienone-enone chromophore.     

Alcyonolide,a novel diterpenoid from a soft coral

A novel diterpenoid acetate named alcyonolide has been isolated from an Okinawan soft coral of the genus $\text{Alcyonium}$ and the absolute stereostructure $\text{1}$ has been assigned on the basis of chemical and physicochemical evidence.     

New 6-hydroxyeunicellins from a soft coral Cladiella sp

Two new 6-hydroxyeunicellin diterpenoids, cladieunicellin G (1) and 6-epi-cladieunicellin F (2), were isolated from an Indonesian octocoral Cladiella sp. The structures of eunicellins 1 and 2 were established by spectroscopic methods and 2 was found to be an epimer of the known eunicellin cladieunicellin F (3). Eunicellin 2 displayed inhibitory effects on the generation of superoxide anion and the release of elastase by human neutrophils.     

Two new xeniolides from a Taiwanese Xenia soft coral

Chromatographic investigation of an extract of the octocoral Xenia umbellata afforded two new diterpenes, xenibelatols A (1) and B (2), in addition to three known xenicane diterpenes, 7,8-oxidoisoxeniolide (3), 9-hydroxyxeniolide F (4), and florlide C, and a cadinene sesquiterpene, xenitorin A (5). The structures were elucidated through spectroscopic analysis, especially 2D NMR.     

A diterpene related to cladiellin from a pacific soft coral

A new diterpene $\text{2}$ from a soft coral collected at Majuro Atoll has been related to cladiellin ($\text{1}$.     

A novel chlorinated norsesquiterpenoid and two related new metabolites from the soft coral Paralemnalia thyrsoides

A structurally unique chlorinated norsesquiterpenoid, paralemnolin A (1), along with two new metabolites, paralemnolin B (2) and C (3), have been isolated from the soft coral Paralemnalia thyrsoides. Their structures were determined by extensive spectroscopic analyses. Single-crystal X-ray diffraction analysis of 1 further establish the absolute stereochemistry of 1.     

Briaviodiol A, a new Cembranoid from a soft coral Briareum violacea

A new cembrane diterpenoid, briaviodiol A (1), has been isolated from a soft coral Briareum violacea. The structure of 1 was determined by spectroscopic methods and further confirmed by a single-crystal X-ray diffraction analysis.