Two new biscembranes with unprecedented carbon skeleton and their probable biogenetic precursor from the Hainan soft coral Sarcophyton latum

A new cembranolide diterpene, isosarcophytonolide D (1), and two biscembranes with an unprecedented fused carbon skeleton, bislatumlides A (3) and B (4), were isolated from the Hainan soft coral Sarcophyton latum. Their structures and relative stereochemistry were established by 1D and 2D NMR spectroscopic techniques. Compounds 3 and 4 should be obtained by Diels-Alder addition of two cembranoid units. Compound 1 could be one of the biosynthetic precursors. Both 3 and 4 showed mild cytotoxicity toward A549, HT-29, and P388 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.     

A novel symmetric sulfur-containing biscembranoid from the Formosan soft coral Sinularia flexibilis

A structurally unique symmetric sulfur-containing biscembranoid, namely, thioflexibilolide A (1), was isolated from the soft coral Sinularia flexibilis. The structure was determined by extensive spectroscopic analyses. Compound 1 has been found to possess significant anti-inflammatory and neuroprotective activities.     

Novaxenicins A-D and xeniolides I-K, seven new diterpenes from the soft coral Xenia novaebrittanniae

Seven new diterpenes, novaxenicins A-D (1-4) and xeniolides I-K (5-7), have been isolated from the Kenyan soft coral Xenia novaebrittanniae. The structures and relative stereochemistry of the compounds were elucidated by interpretation of MS, COSY, HSQC, HMBC, and NOESY experiments. The structure of novaxenicin A (1) was secured by X-ray diffraction analysis. Compound 5 possesses anti-bacterial activity at a concentration of 1.25 μg/ml and compound 2 induces apoptosis in transformed mammalian cells at a concentration of 1.25 μg/ml.     

Antibacterial effect of the red sea soft coral Sarcophyton trocheliophorum

The marine soft corals Sarcophyton trocheliophorum crude extracts possessed antimicrobial activity towards pathogenic bacterial strains, i.e. Bacillus cereus, Salmonella typhi, Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. Bioassay-guided fractionation indicated that the antimicrobial effect was due to the presence of terpenoid bioactive derivatives. Further biological assays of the n-hexane fractions were carried out using turbidity assay, inhibition zone assay and minimum inhibitory concentration for investigating the growth-inhibition effect towards the Gram-positive and Gram-negative bacteria. The fractions were screened and the structure of the isolated compound was justified by interpretation of the spectroscopic data, mainly mass spectrometry (GC-MS). The structure was assigned as (5S)-3-[(3E,5S)-5-hydroxy-3-hepten-6-yn-1-yl]-5-methyl-2(5H)-furanone and was effective at concentrations as low as 0.20 mg/mL. The above findings, in the course of our ongoing research on marine products, may implicate that the profound anti-microbial activity of the S. trocheliophorum soft corals, inhabiting the red sea reefs, is attributed to the presence of growth-inhibiting secondary metabolites mainly terpenoids.     

Novel sesquiterpenoids from the Formosan soft coral Paralemnalia thyrsoides

Three sesquiterpenoids with unprecedented skeletons, paralemnanone (1), isoparalemnanone (2), and paralemnanol (3), were isolated from the Formosan soft coral Paralemnalia thyrsoides. Their structures were elucidated by extensive spectroscopic analysis, and the structure of 1 was further confirmed by X-ray crystallographic analysis. The absolute stereochemistries of 1-3 were established by application of the Mosher’s method on 2.     

软珊瑚Sarcophyton sp.中一个新的西松烷二萜内酯的分离及结构测定

肉芝软珊瑚 Sarcophyton富含二萜 ,从这类软珊瑚生物体中已经分离出许多含十四元环结构的西Scheme 1　 Sturcture of Sarcophydiol 1松烷二萜内酯 ,例如 Sarcophinone[1] ,iso-Sarcophinone[2 ] ,Sarcophine[3,4 ] ,Sartrochine[5] 和 iso-Sarcophine[6 ,7] .这些西松烷二萜内酯均有较强的细胞毒性 .在对采自南中国海的一种肉芝软珊瑚 Sar-cophyton sp.次生代谢产物的研究过程中 ,我们分离得到一个在生源上与 iso- Sarcophine有密切关系的新西松烷二萜内酯 Sarcophydiol 1 (结构见Scheme 1 ) .本文报道其分离方法及结构测定结果 .1　…     

Sardisterol,A New Polyhydroxylated Sterol from the Soft Coral Sarcophyton digitatum Moser

A new polyhydroxylated sterol, named sardisterol, was isolated from the soft coral Sarcophyton digitatum Moser. Its structure was determined as (22R, 24ξ)‐methylcholest‐5‐en‐3β, 22, 25, 28‐tetraol‐3‐acetate on the basis of spectroscopic methods.     

Novel Polyhydroxysteroids from the Formosan Soft Coral Sarcophyton Glaucum

Two novel polyhydroxysteroids, (24S)‐24‐methylcholestane‐3β,5α,6β,25ξ;,26‐pentol 26‐n‐decanoate ( 1 ), (24S)‐24‐methylcholestane‐3β,5α,6β,25ξ;,26‐pentol 25,26‐diacetate ( 2 ), and three known sterols ( 3‐5 ), have been isolated from a Formosan soft coral Sarcophyton glaucum. The molecular structures of these compounds were determined by spectral methods. The cytotoxicity of these compounds toward various cancer cell lines has also been determined.     

软珊瑚Sarcophyton crassocaule中Cembrane型二萜的分离与鉴定

从采自中国南海西沙群岛海域的软珊瑚Sarcophytoncrassocaule中分离得到一种结构新颖的Cembrane型二萜,经¹HNMR,¹³CNMR,HMQC,¹H-¹HCOSY,NOESY,FABMS和X射线晶体衍射确定其结构,命名为SarcocrassolideB它对P388的细胞毒性为1.5μg/mL.     

Novel cyclic sesquiterpene peroxides from the Formosan soft coral Sinularia sp.

Four novel cyclic peroxide-containing sesquiterpenes (1-4), with a γ-alkylidene-α-methyl-α,β-unsaturated γ-lactone moiety, have been isolated from a Formosan soft coral of the genus Sinularia. Their structures were elucidated mainly by extensive 1D and 2D NMR experiments.     

Isolation of a new cytotoxic polyhydroxysterol from the South China Sea soft coral Sinularia sp.

A new polyhydroxysterol, (22E)-24-methylenecholestane-22-ene-3β,5α,6β-triol (1), together with four known analogues (2–5) were isolated from the South China Sea soft coral Sinularia sp. Their structures were elucidated by spectroscopic analyses and comparison with previously reported data. All these compounds exhibited cytotoxic effect against both HepG2 and HeLa cell lines with IC₅₀ values ranging from 8.36 to 37.30 μM. Preliminary structure–activity relationship study identified that the presence of double bonds in the side chains of these polyhydroxysterols significantly reduced the biological effect obtained.     

Sarcoconvolutums F and G: Polyoxygenated Cembrane-Type Diterpenoids from Sarcophyton convolutum,a Red Sea Soft Coral

Natural products and chemical analogues are widely used in drug discovery, notably in cancer and infectious disease pharmacotherapy. Sarcophyton convolutum (Alcyoniidae) a Red Sea–derived soft coral has been shown to be a rich source of macrocyclic diterpenes and cyclized derivatives. Two previously undescribed polyoxygenated cembrane-type diterpenoids, sarcoconvolutums F (1) and G (2), as well as four identified analogues (3–6) together with a furan derivate (7) were isolated from a solvent extract. Compounds were identified by spectroscopic techniques, including NMR, HREIMS, and CD, together with close spectral comparisons of previously published data. Sarcoconvolutum F (1) contains a rare 1-peroxid-15-hydroxy-10-ene functionality. Isolated metabolites (1–7) were screened against lung adenocarcinoma (A549), cervical cancer (HeLa) and oral cavity carcinoma (HSC-2) lines. Compound 4 exhibited an IC₅₀ 56 µM and 55 µM against A549 and HSC-2 cells, respectively.     

Durumolides A-E, anti-inflammatory and antibacterial cembranolides from the soft coral Lobophytum durum

Chemical investigations on the acetone extract of the soft coral Lobophytum durum have afforded five new cembranoids with a trans-fused α-methylene-γ-lactone, durumolides A-E (1, 6, and 8-10), and five previously characterized cembrane-based diterpenoids (2-5 and 7). The structures of the isolated metabolites were elucidated through extensive spectroscopic analyses, while the relative stereochemistry of 4 was confirmed by X-ray diffraction analyses. Moreover, the absolute configurations of 3-5 and 8 were established by application of modified Mosher's method. The anti-inflammatory effects, antibacterial activities, and inhibition assay of HCMV (Human cytomegalovirus) endonuclease activity of these isolated metabolites 1-10 were evaluated in vitro.     

Studies on the Formosan Soft Corals I-Cytotoxic Cembrane Diterpenes from Sarcophyton Trocheliophorum

Two cytotoxic cembranoid diterpenes, (+)-isosarcophytoxide (1) and ( + )-isosarcophine (2), were isolated from the soft coral Sarcophyton trocheliophorum by cytotoxicity-guided fractionation. These two compounds demonstrated potent cytotoxicity against P-388 and HL-60 cells.     

Pavidolides A-E, new cembranoids from the soft coral Sinularia pavida

Five new cembrane-based diterpenoids, namely pavidolides A-E (1-5) were isolated from the marine soft coral Sinularia pavida, together with sarcophytin and chatancin. The structures of new compounds were determined on the basis of extensive spectroscopic data analysis. Pavidolide B (2) possesses an unprecedented 6,5,7-tricarbocyclic nucleus, whereas pavidolide C (3) is characteristic of an unusual C-5 and C-9 conjuncted cembranoid. Pavidolides C and D showed moderate antifouling activity against the larval settlement of barnacle Balanus amphitrite, while pavidolides B and C exhibited inhibitory activity against the human leukemia cell line HL-60.     

Sinuhirtins A and B,two uncommon norhumulene-type terpenoids from the South China Sea soft coral Sinularia hirta

Two new uncommon norhumulene-type norsesquiterpenoids, namely sinuhirtins A (1) and B (2), along with two known norcaryophyllene-type norsesquiterpenoids (3 and 4), were isolated from the South China Sea soft coral Sinularia hirta. The structures and absolute configurations of the new compounds were determined by extensive spectroscopic data analyses, and computer-assisted methods including GIAO ¹³C NMR and TDDFT-ECD calculations. A plausible biogenetic relationship of 1–4 was proposed.     

Clavirolide G,a new rare dolabellane-type diterpenoid from the Xisha soft coral Clavularia viridis

One new dolabellane-type diterpenoid,named clavirolide G(1),and one known related analogue(3), have been isolated from the soft coral Clavularia viridis collected off the Xisha Islands in the South China Sea.Its structure and absolute configuration were determined on the basis of spectroscopic analysis, electronic circular dichroism,and compared with literature model compounds.The cytotoxic activity of these two compounds was evaluated against a panel of human tumor cell lines.Compound 1 showed moderate cytotoxic activity against KB and HL-60 cells.     

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.     

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.