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At least 1,747 records · Page 97Linked to original sources
PubMed1993

A new procedure for the isolation of anti-HIV compounds (polysaccharides and polyphenols) from the marine alga Fucus vesiculosus.

Anti-HIV-active polysaccharides and polyphenols were isolated from the brown seaweed Fucus vesiculosus by hot H2O extraction of both the intact and the homogenized algae. This was followed by XAD2 chromatography and by sequential precipitation of the non-adsorbed compounds with glacial HOAc and thereafter with EtOH. The precipitate was solubilized, dialyzed against distilled H2O, and chromatographed on SP-Sephadex C25 and on QAE-Sephadex A25. This was followed by gel filtration on Sephadex G50 and Sephadex G100 and finally by hplc on a Shodex Ionpak S-804 column. For comparison, the commercial product fucoidan, a sulfated algal polysaccharide, was also further purified by the chromatographic techniques mentioned above. The isolated freeze-dried fractions obtained by these procedures were tested for inhibition of both HIV-induced syncytium formation and HIV reverse transcriptase enzyme activity. Some of these fractions inhibited both of these activities at concentrations that were not cytotoxic.

Antiviral Agents↗
PubMed1993

Cytotoxic diterpenoids from the brown alga Dilophus ligulatus.

A new xenicane-type diterpene, dilopholide [5], and four known diterpenoids, acetoxycrenulide [1], acetylcoriacenone [2], and its epimer isoacetylcoriacenone [3], and hydroxyacetyldictyolal [4], have been isolated from the brown alga Dilophus ligulatus [syn. spiralis (Montagne) Hamel]. The structure of dilopholide [5] was elucidated by spectroscopic methods, including the concerted application of a number of 2D nmr techniques, including 1H-1H COSY, heteronuclear proton-carbon chemical shift correlation (HETCOSY), and long-range HETCOSY. The cytotoxic activity of compounds 1-5 has been examined against several types of mammalian cells: human nasopharynx carcinoma cells (KB), human lung carcinoma cells (NSCLC-N6), murine leukemia cells (P-388), and murine leukemia cells expressing the multi-drug-resistance gene, mdr (P-388/DOX).

Antineoplastic Agents↗
PubMed1994

The absolute configuration of ecklonialactones A, B, and E, novel oxylipins from brown algae of the genera Ecklonia and Egregia.

Ecklonialactones A, B, and E, previously isolated from the brown alga Ecklonia stolonifera, have been isolated from the Oregon phaeophyte Egregia menziesii. The structure and relative stereochemistry of ecklonialactone E were independently determined by various nmr techniques. The absolute stereochemistry of ecklonialactone A was deduced by cd analysis of a dibenzoate derivative, which indicated it possessed a 11S, 12R, 13S, 15R, 16S stereochemistry. Similar 1H- and 13C-nmr data and optical rotations for all of the ecklonialactones indicate that B and E have the same stereochemistry as A at comparable stereocenters.

Bridged Bicyclo Compounds↗
PubMed1994

beta-Carbolines from the blue-green alga Dichothrix baueriana.

Three new chlorine-containing beta-carbolines, bauerines A-C (1-3), have been isolted from the terrestrial blue-green alga Dichothrix baueriana GO-25-2, and identifying mass and nmr spectral analysis. The alkaloids show activity against herpes simplex virus type 2.

Animals↗
PubMed1994

Absolute stereochemistry of neohalicholactone from the brown alga Laminaria sinclairii.

Phytochemical analysis of an extract from the brown alga Laminaria sinclairii led to the isolation of neohalicholactone, a cyclopropyl-containing oxylipin previously isolated from a marine sponge, Halichondria okadai. Unequivocal stereochemical analysis of the C-15 hydroxyl group showed this isolate to be of opposite overall absolute stereochemistry compared to that proposed for halicholactone, a related compound from the sponge, and by our inference, sponge-derived neohalicholactone. Comparison of chiroptical data for all three compounds indicates the absolute stereochemistry of the sponge compounds is most probably opposite to that previously proposed.

Cyclopropanes↗
PubMed1996

Cytotoxic oxygenated desmosterols of the red alga Galaxaura marginata.

Desmosterol (1), 24,25-epoxycholesterol (2), 24-hydroperoxycholesta-5,25-dien-3 beta-ol (3), 25-hydroperoxycholesta-5,23(E)-dien-3 beta-ol (4), cholesta-5,25-diene-3 beta,24-diol (5), and 24,25-epoxy-6 beta-hydroxycholest-4-en-3-one (7) were isolated from the marine red alga Galaxaura marginata; sterols 3, 4, and 7 were isolated for the first time from a natural source. Sterols 3-7 exhibited significant cytotoxicity toward several cancer cell lines.

Animals↗
PubMed1996

Calcium spirulan, an inhibitor of enveloped virus replication, from a blue-green alga Spirulina platensis.

Bioactivity-directed fractionation of a hot H2O extract from a blue-green alga Spirulina platensis led to the isolation of a novel sulfated polysaccharide named calcium spirulan (Ca-SP) as an antiviral principle. This polysaccharide was composed of rhamnose, ribose, mannose, fructose, galactose, xylose, glucose, glucuronic acid, galacturonic acid, sulfate, and calcium. Ca-SP was found to inhibit the replication of several enveloped viruses, including Herpes simplex virus type 1, human cytomegalovirus, measles virus, mumps virus, influenza A virus, and HIV-1. It was revealed that Ca-SP selectively inhibited the penetration of virus into host cells. Retention of molecular conformation by chelation of calcium ion with sulfate groups was suggested to be indispensable to its antiviral effect.

Antiviral Agents↗
PubMed1996

Dendroamides, new cyclic hexapeptides from a blue-green alga. Multidrug-resistance reversing activity of dendroamide A.

Dendroamide A (1), one of three new bistratamide-type cyclic hexapeptides from the terrestrial blue-green alga (cyanobacterium) Stigonema dendroideum Fremy, exhibits multidrug-resistance reversing activity. The gross structures of the three compounds, dendroamides A-C, were determined by NMR and mass spectral analyses. Their absolute stereochemistries were determined by Marfey and chiral GC/MS analyses of derivatives formed from acid hydrolysis of the intact and ozonized peptides.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1997

Isolation and structure determination of sulfonoquinovosyl dipalmitoyl glyceride, a P-selectin receptor inhibitor from the alga Dictyochloris fragrans.

Bioassay-guided fractionation of the marine alga Dictyochloris fragrans led to the isolation and identification of sulfonoquinovosyl dipalmitoyl glyceride (1). The structure of 1 was determined by a combination of spectroscopic methods. On the basis of P-selectin inhibition assays (i.e., P-selectin-IgG ELISA, cell binding assay of receptor globulin, and platelet:HL60 adhesion, it was demonstrated that 1 selectively blocks the P-selectin-ligand interaction in vitro and could be considered a lead compound for synthetic modification in order to design more potent inhibitors of cell adhesion processes that play important roles in development of inflammatory-mediated disease states.

Cell Adhesion↗
PubMed1997

Study on cytotoxic oxygenated desmosterols isolated from the red alga Galaxaura marginata.

Four novel oxygenated desmosterols, 24 zeta-hydroperoxy-6 beta-hydroxycholesta-4,25-dien-3-one (1), 25-hydroperoxy-6 beta-hydroxycholesta-4,23(E)-dien-3-one (2), 24 zeta-hydroperoxycholesta-4,25-diene-3,6-dione (3), and 25-hydroperoxycholesta-4,23(E)-diene-3,6-dione (4) were isolated from the marine red alga Galaxaura marginata. Steroids 1-4 and three synthetic oxygenated desmosterols 5-7 were shown to exhibit significant cytotoxicity against several cancer cell lines.

Animals↗
PubMed1998

Gloeolactone, a New Epoxy Lactone from a Blue-Green Alga

A novel lactone, gloeolactone (1), has been isolated from the blue-green alga, Gloeotrichia sp. The structure of this compound has been elucidated from a detailed analysis of the NMR spectra. This compound was shown to be toxic to brine shrimp.

Journal Article↗
PubMed1998

Malyngamides M and N from the Hawaiian Red Alga Gracilaria coronopifolia

Two new malyngamides, M and N (1, 2), were isolated along with malyngamide I acetate (3) from the Hawaiian red alga Gracilaria coronopifolia. Our results suggest that malyngamide N (2) is a revised structure of deacetoxystylocheilamide (5). The absolute configuration of malyngamide I acetate was deduced to be 3 using the reversed octant rule.

Journal Article↗
PubMed1998

A new indole derivative from the red alga Chondria atropurpurea. Isolation, structure determination, and anthelmintic activity.

Chondriamide C (3), a new bis(indole) amide, was isolated from the red alga Chondria atropurpurea, and its structure was established from spectroscopic data and chemical transformations. A new natural product, 3-indoleacrylamide (4), and the previously described chondriamides A and B (1, 2) and 3-indoleacrylic acid (5) were also isolated. The anthelmintic activities of compounds 1, 3, 4, and 6 (the O,N1,N1'-trimethyl derivative of compound 2) against Nippostrongylus brasiliensis in vitro were evaluated.

Albendazole↗
PubMed1999

New cytotoxic oxygenated fucosterols from the brown alga Turbinaria conoides.

Fucosterol (1), 24xi-hydroperoxy-24-vinylcholesterol (2), 29-hydroperoxystigmasta-5,24(28)-dien-3beta-ol (3), 24-ethylcholesta-4,24(28)-dien-3-one (4), 24xi-hydroperoxy-24-ethylcholesta-4,28(29)-dien-3-one (5), 24-ethylcholesta-4,24(28)-dien-3,6-dione (6), 24xi-hydroperoxy-24-ethylcholesta-4,28(29)-dien-3,6-di one (7), 6beta-hydroxy-24-ethylcholesta-4,24(28)-dien-3-one (8), and 24xi-hydroperoxy-6beta-hydroxy-24-ethylcholesta-4,28(2 9)-dien-3-one (9) were isolated from the marine brown alga Turbinaria conoides. The structures of these compounds were established by spectral analysis. Isolated for the first time from a natural source, the oxygenated fucosterols 4-9 exhibit cytotoxicity against various cancer cell lines.

Antineoplastic Agents, Phytogenic↗