南海小束格海绵中的天然含氮化合物

目的 研究我国南海小束格海绵Clathria fasciculate的有效化学成分。方法 有机溶剂浸提，柱层析分离纯化，利用UV，IR，MS，^1H-NMR，^13C-NMR和二维棱磁共振等实验确定纯物质的化学结构，并根据旋光值确定化合物的立体化学。结果与结论从该海绵正丁醇可溶部分获得6个含氮化合物：腺嘌呤棱糖棱苷（Ⅰ），尿嘧啶棱糖棱苷（Ⅱ），胸腺嘧啶脱氧棱苷（Ⅲ），次黄嘌呤（Ⅳ），胸腺嘧啶（Ⅴ）和尿嘧啶（Ⅵ）．     

南海海绵Clathria f asciculate化学成分的研究(Ⅰ)

从中国南海海绵Clathria fasciculate的乙酸乙酯可溶部分分离获得11个纯有机化合物，经Lieber-mann-Burchard试验和IR、^1H-NMR、`13C－NMR、DEPT、EIMS等波谱技术，确定其中的3个为甾醇类化合物，分别是：胆甾－6－烯－5α，8α－环二氧－3β－醇（Ⅰ）；（24s）－豆甾－5－烯－3β－醇（Ⅱ）和胆甾醇（Ⅲ）。其余几个化合物的结构仍在鉴定之中。     

Two new indole derivatives from a marine sponge Ircinia sp. collected at Iriomote Island

Journal of Natural Medicines - Two new indole derivatives, 5-hydroxy-1H-indole-3-carboxylic acid ethyl ester (1) and 5-hydroxy-1H-indole-3-glyoxylate ethyl ester (2), and seven known indole...     

南海海绵Clathria fasciculate化学成分的研究(Ⅱ)

从中国南海海绵Clathria fasciculate的乙酸乙酯相分离鉴定出4个有机化合物，经GC-MS，FAB，IR，^1HNMR,^13CNMR和COSY等波谱技术确定它们分别是：胆甾-4-烯-3-酮（Ⅰ）；豆甾-4-烯-3-酮（Ⅱ）；（Z）-17-二十四碳烯-1-醇（Ⅲ）和1-（17Z-二十四碳烯基）-甘油醚（Ⅳ），为首次有关该种属海绵化学成分研究系列的第二次报道。     

O-methyl nakafuran-8 lactone, a new sesquiterpenoid from a hainan marine sponge Dysidea sp

A new sesquiterpenoid, O-methyl nakafuran-8 lactone (1) has been isolated from a Hainan sponge Dysidea sp. and the structure of the new compound proposed by spectral data, was confirmed by X-ray diffraction analysis. The complete ¹H- and ¹³C-NMR assignments were made on the basis of detailed 2D NMR spectral analysis.

Compound 1 showed strong inhibitory bioactivity against PTP1B with IC₅₀ value of 1.58 μM.     

Three new polyunsaturated lipids from a Guangxi marine sponge Haliclona sp.

Three new polyunsaturated lipids, (6Z,9Z,12Z,15Z)-octadeca-6,9,12,15-tetraen-3-one (1), (6Z,9Z,12Z,15Z)-1-bromooctadeca-6,9,12,15-tetraen-3-one (2), and (Z)-ethyl docos-5-enoate (3), together with two known polyunsaturated lipids, 4(Z),7(Z),10(Z)-tridecatrienoic acid (4) and (6Z,9Z,12Z,15Z)-octadeca-1,6,9,12,15-pentaen-3-one (5), were isolated from the marine sponge Haliclona sp., which was collected from Guangxi, using HSCCC and HPLC methods. Chemical structures of the five compounds were elucidated by spectroscopic techniques.     

Two new imidazole alkaloids from Leucetta chagosensis sponge

Chemical investigation of the sponge Leucetta chagosensis, has led to the isolation of two new imidazole alkaloids, methyldorimidazole (1), preclathridine B (2) along with the known compounds naamine E (3) and leucettamine C (4). The structures of the newly compounds (1 and 2) were elucidated by employing spectroscopic techniques (¹H NMR, MS and UV). The structures of the known compounds 3 and 4 were determined by comparison of their ¹H NMR and Mass spectroscopic data with published values.     

3-Oxo-axisonitrile-3, a new sesquiterpene isocyanide from the Chinese marine sponge Acanthella sp

A new sesquiterpene isocyanide, 3-oxo-axisonitrile-3 (1), with a spiro [5,6] decane skeleton (spiroaxane) together with a known related sesquiterpene isonitrile (2), sesquiterpene isothiocyanates (3-8) and two diterpene isonitriles (9, 10) have been isolated from the Chinese marine sponge Acanthella sp. The structure of 1 has been determined on the basis of spectroscopic analysis.     

Calyculatine: a new dolabellane diterpenoid from the marine sponge Eunicea calyculata

A new dolabellane diterpenoid, 7(S)-hydroperoxy-13-keto-(1S,11R)-dolabella-3(E),8(17),12(18)-triene (1), and two known compounds, 7(S),8(S)epoxy-13-keto-1(S),11(R)-dolabella-3(E),12 (18)-diene (2) and 13-keto-1(S),11(R)-dolabella-3(E),7(E),12(18)-triene (3), were isolated from the marine sponge Eunicea calyculata. The structure of 1 was elucidated by 1D (1)H- and (13)C-NMR spectra and 2D HMQC, HMBC, and the relative stereochemistry was established by analysis of coupling constants and NOESY spectra. In addition, an X-ray crystallographic analysis on a single crystal of 2 was carried out. Compounds 1 and 2 were inactive in the hyphae formation inhibition assay (HFI) in Streptomyces 85E while compound 3 showed inhibitory activity at a concentration of 20 microg/20 microL in the HFI assay.     

A new brominated polyacetylene from Chinese marine sponge Xestospongia testudinaria

A new brominated polyacetylene xestonariene J (1), bearing a rare 2,4-dibromo-1-ene-3-yne terminal in the molecule, along with two known related analogues (2 and 3), was obtained from Chinese marine sponge Xestospongia testudinaria. Its structure was determined on the basis of detailed spectroscopic analysis and comparison with literature data.

     

3-Oxo-axisonitrile-3, a new sesquiterpene isocyanide from the Chinese marine sponge Acanthella sp.

A new sesquiterpene isocyanide, 3-oxo-axisonitrile-3 (1), with a spiro [5 Alvi, K.A., Tenenbaum, L. and Crews, P. 1991. J. Nat. Prod., 54: 71[Crossref], [PubMed], [Web of Science ®] , [Google Scholar],6 Burgoyne, D.L. and Dumdei, E.J. 1993. Tetrahedron, 49: 4503 [Google Scholar]] decane skeleton (spiroaxane) together with a known related sesquiterpene isonitrile (2), sesquiterpene isothiocyanates (3–8) and two diterpene isonitriles (9, 10) have been isolated from the Chinese marine sponge Acanthella sp. The structure of 1 has been determined on the basis of spectroscopic analysis.     

Stellettamide-A,a novel inhibitor of calmodulin,isolated from a marine sponge

1. Stellettamide A (ST-A), a novel marine toxin isolated from a marine sponge, inhibited high K⁺(72.7 mM)-induced contraction in the smooth muscle of guinea-pig taenia coli with an IC₅₀ of 88 μM.
2. In the taenia permeabilized with Triton X-100, ST-A inhibited Ca²⁺ (3 and 10 μM)-induced contractions with an IC₅₀ of 46 μM for 3 μM Ca²⁺ and 105 μM for 10 μM Ca²⁺. In the permeabilized taenia, calyculin-A (300 nM), a potent inhibitor of type-1 and type-2A phosphatases, induced sustained contraction in the absence of Ca²⁺. ST-A had no effect on this contraction.
3. ST-A inhibited Mg²⁺-ATPase activity in native actomyosin prepared from chicken gizzard with an IC₅₀ of 25 μM.
4. In a reconstituted smooth muscle contractile system containing calmodulin, myosin light chain (MLC) and MLC kinase, ST-A inhibited MLC phosphorylation with an IC₅₀ of 152 μM. The inhibitory effect of ST-A was antagonized by increasing the concentration of calmodulin.
5. ST-A inhibited calmodulin activity, assessed by Ca²⁺/calmodulin-dependent enzymes, (Ca²⁺-Mg²⁺)-ATPase of erythrocyte membrane, with an IC₅₀ of 100 μM and phosphodiesterase prepared from bovine cardiac muscle with an IC₅₀ of 52 μM. The inhibitory effect on phosphodiesterase activity was antagonized by increasing the calmodulin concentration.
6. Interaction between ST-A and calmodulin was demonstrated by instantaneous quenching of the intrinsic tyrosine fluorescence of calmodulin by ST-A (3–300 μM). Similar results were obtained in the presence or absence of Ca²⁺ suggesting that ST-A binds to calmodulin and that Ca²⁺ is not essential for the binding of ST-A to calmodulin.
7. These results suggest that ST-A, isolated from marine metabolites, is a novel inhibitor of calmodulin.

     

Two novel alkaloids from the South China Sea marine sponge Dysidea sp

Two new alkaloids, dysideanins A (1) and B (2), along with two known diketopiperazines, cyclo-(Pro-Leu) (3) and cyclo-(Pro-Ile) (4), were isolated from the marine sponge Dysidea sp. The structures were established from NMR and MS analysis. Dysideanin B (2) exhibited antibacterial activity. The thiomethylated imidazolinium unit as found in dysideanin A is very rarely encountered in nature.     

Cytotoxic effects of three new metabolites from Red Sea marine sponge,Petrosia sp.

Marine sponges represent an affluent source of biogenetically unprecedented array of biologically active compounds. This study revealed the isolation of ten compounds from marine sponge of Petrosia sp. Their chemical structures were determined by using 1D and 2D NMR, UV, IR and MS measurements. A polyoxygenated steroid (3β,7β,9α-trihydroxycholest-5-en (1), a purine-derivative (3,7-dimethyl-2-(methylamino)-3H-purin-6(7H)-one (2) and a sphingolipid (N-((3S,E)-1,3-dihydroxytetracos-4-en-2-yl)stearamide (3) proved to be new compounds. Meanwhile, seven known compounds; (4–10) were also identified. The cytotoxicity of the total extract and the isolated compounds were subjected to cytotoxicity evaluation employing two cancer cell lines; HepG2 and MCF-7. All tested compounds exhibited cytotoxic effect on both cancer cell lines with IC₅₀ in range of 20-500 μM. The proposed mechanism of cytotoxic activities was examined through its molecular affinity to the DNA. Compound 5 showed the highest affinity to the DNA with IC₅₀ 30 μg/mL.     

Two new 18-en-oleane derivatives from marine mangrove plant, Barringtonia racemosa

Two new triterpenoids, olean-18-en-3beta-O-E-coumaroyl ester (1) and olean-18-en-3beta-O-Z-coumaroyl ester (2), were isolated from the stem bark of marine mangrove plant Barringtonia racemosa, along with five known compounds, germanicol, germanicone, betulinic acid, lupeol, and taraxerol. Their structures were determined mainly by spectroscopic methods.     

New bioactive bromotyrosine-derived alkaloid from a marine sponge Aplysinella sp

A new bromotyrosine-derived alkaloid, (+)-aplysinillin (1), together with seven known compounds, was isolated from the crude organic extract of the marine sponge Aplysinella sp. collected from the Federated States of Micronesia. The structure of 1 was deduced by NMR and mass spectral techniques. Compounds 1-8 were evaluated for their inhibitory activity with the hyphae formation inhibition assay in Streptomyces 85E. Compounds 1 and 8 exhibited antiproliferative activities against the human breast adenocarcinoma cancer cell line MCF-7.