Marine Drugs

500 KiB

Open AccessArticle

Limited Impact of 2 g/day Omega-3 Fatty Acid Ethyl Esters (Omacor^®) on Plasma Lipids and Inflammatory Markers in Patients Awaiting Carotid Endarterectomy

by Hayati M. Yusof, Abbie L. Cawood, Ren Ding, Jennifer A. Williams, Frances L. Napper, Clifford P. Shearman, Robert F. Grimble, Simon P.K. Payne and Philip C. Calder

Mar. Drugs 2013, 11(9), 3569-3581; https://doi.org/10.3390/md11093569 - 20 Sep 2013

Cited by 22 | Viewed by 8250

Abstract

The objective of this study was to determine the effects of prescription omega-3 (n-3) fatty acid ethyl esters (Omacor^®) on blood pressure, plasma lipids, and inflammatory marker concentrations in patients awaiting carotid endarterectomy. Patients awaiting carotid endarterectomy (n [...] Read more.

The objective of this study was to determine the effects of prescription omega-3 (n-3) fatty acid ethyl esters (Omacor^®) on blood pressure, plasma lipids, and inflammatory marker concentrations in patients awaiting carotid endarterectomy. Patients awaiting carotid endarterectomy (n = 121) were randomised to Omacor^® or olive oil as placebo (2 g/day) until surgery (median 21 days). Blood pressure, plasma lipids, and plasma inflammatory markers were determined. There were significant decreases in systolic and diastolic blood pressure and in plasma triglyceride, total cholesterol, low density lipoprotein-cholesterol, soluble vascular cellular adhesion molecule 1, and matrix metalloproteinase 2 concentrations, in both groups. The extent of triglyceride lowering was greater with Omacor^® (25%) compared with placebo (9%). Soluble E-selectin concentration was significantly decreased in the Omacor^® group but increased in the placebo group. At the end of the supplementation period there were no differences in blood pressure or in plasma lipid and inflammatory marker concentrations between the two groups. It is concluded that Omacor^® given at 2 g/day for an average of 21 days to patients with advanced carotid atherosclerosis lowers triglycerides and soluble E-selectin concentrations, but has limited broad impact on the plasma lipid profile or on inflammatory markers. This may be because the duration of intervention was too short or the dose of n-3 fatty acids was too low. Full article

(This article belongs to the Special Issue Marine Fatty Acids-2013)

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463 KiB

Open AccessArticle

Adverse Effect of Antifouling Compounds on the Reproductive Mechanisms of the Ascidian Ciona intestinalis

by Alessandra Gallo and Elisabetta Tosti

Mar. Drugs 2013, 11(9), 3554-3568; https://doi.org/10.3390/md11093554 - 20 Sep 2013

Cited by 28 | Viewed by 6655

Abstract

Fertilization and embryo development that occur in sea water are sensitive to xenobiotics from anthropogenic sources. In this work, we evaluated the influence of two antifouling biocides, tributyltin (TBT) and diuron, on the reproductive mechanisms of the marine invertebrate Ciona intestinalis. By [...] Read more.

Fertilization and embryo development that occur in sea water are sensitive to xenobiotics from anthropogenic sources. In this work, we evaluated the influence of two antifouling biocides, tributyltin (TBT) and diuron, on the reproductive mechanisms of the marine invertebrate Ciona intestinalis. By using electrophysiological techniques, we examined the impact of these compounds on the electrical properties of the mature oocytes and of events occurring at fertilization. With different toxicity assays, we studied the effect of the two biocides on the gametes by evaluating fertilization rate and embryo development. Results show that sodium (Na⁺) currents were significantly reduced by either of the two biocides, whereas conductance was significantly increased. The fertilization current frequency and amplitude, fertilization rate and larval development were affected only by TBT. This study suggests that: (i) the two biocides affect either the electrical properties of the oocyte plasma membrane and the reproductive success representing a risk factor for the survival of the species exposed to environmental pollution; (ii) the ascidian Ciona intestinalis may represent a good model organism to test toxicity of marine pollutants. Possible mechanisms of action of the two biocides are discussed. Full article

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Open AccessArticle

Optimal Cleavage and Oxidative Folding of α-Conotoxin TxIB as a Therapeutic Candidate Peptide

by Xiaosa Wu, Yong Wu, Furong Zhu, Qiuyuan Yang, Qianqian Wu, Dongting Zhangsun and Sulan Luo

Mar. Drugs 2013, 11(9), 3537-3553; https://doi.org/10.3390/md11093537 - 17 Sep 2013

Cited by 17 | Viewed by 7533

Abstract

Alpha6beta2 nicotinic acetylcholine receptors (nAChRs) are potential therapeutic targets for the treatment of several neuropsychiatric diseases, including addiction and Parkinson’s disease. Alpha-conotoxin (α-CTx) TxIB is a uniquely selective ligand, which blocks α6/α3β2β3 nAChRs only, but does not block the other subtypes. Therefore, α-CTx [...] Read more.

Alpha6beta2 nicotinic acetylcholine receptors (nAChRs) are potential therapeutic targets for the treatment of several neuropsychiatric diseases, including addiction and Parkinson’s disease. Alpha-conotoxin (α-CTx) TxIB is a uniquely selective ligand, which blocks α6/α3β2β3 nAChRs only, but does not block the other subtypes. Therefore, α-CTx TxIB is a valuable therapeutic candidate peptide. Synthesizing enough α-CTx TxIB with high yield production is required for conducting wide-range testing of its potential medicinal applications. The current study optimized the cleavage of synthesized α-CTx TxIB resin-bounded peptide and folding of the cleaved linear peptide. Key parameters influencing cleavage and oxidative folding of α-CTx TxIB were examined, such as buffer, redox agents, pH, salt, co-solvent and temperature. Twelve conditions were used for cleavage optimization. Fifty-four kinds of one-step oxidative solution were used to assess their effects on each α-CTx TxIB isomers’ yield. The result indicated that co-solvent choices were particularly important. Completely oxidative folding of globular isomer was achieved when the NH₄HCO₃or Tris-HCl folding buffer at 4 °C contained 40% of co-solvent DMSO, and GSH:GSSG (2:1) or GSH only with pH 8~8.7. Full article

(This article belongs to the Special Issue Conotoxins)

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Open AccessArticle

Synthesis of Glycyrrhetinic Acid-Modified Chitosan 5-Fluorouracil Nanoparticles and Its Inhibition of Liver Cancer Characteristics in Vitro and in Vivo

by Mingrong Cheng, Xiaoyan Gao, Yong Wang, Houxiang Chen, Bing He, Hongzhi Xu, Yingchun Li, Jiang Han and Zhiping Zhang

Mar. Drugs 2013, 11(9), 3517-3536; https://doi.org/10.3390/md11093517 - 17 Sep 2013

Cited by 68 | Viewed by 10138

Abstract

Nanoparticle drug delivery (NDDS) is a novel system in which the drugs are delivered to the site of action by small particles in the nanometer range. Natural or synthetic polymers are used as vectors in NDDS, as they provide targeted, sustained release and [...] Read more.

Nanoparticle drug delivery (NDDS) is a novel system in which the drugs are delivered to the site of action by small particles in the nanometer range. Natural or synthetic polymers are used as vectors in NDDS, as they provide targeted, sustained release and biodegradability. Here, we used the chitosan and hepatoma cell-specific binding molecule, glycyrrhetinic acid (GA), to synthesize glycyrrhetinic acid-modified chitosan (GA-CTS). The synthetic product was confirmed by Fourier transformed infrared spectroscopy (FT-IR) and ¹H-nuclear magnetic resonance (¹H-NMR). By combining GA-CTS and 5-FU (5-fluorouracil), we obtained a GA-CTS/5-FU nanoparticle, with a particle size of 217.2 nm, a drug loading of 1.56% and a polydispersity index of 0.003. The GA-CTS/5-FU nanoparticle provided a sustained release system comprising three distinct phases of quick, steady and slow release. We demonstrated that the nanoparticle accumulated in the liver. In vitro data indicated that it had a dose- and time-dependent anti-cancer effect. The effective drug exposure time against hepatic cancer cells was increased in comparison with that observed with 5-FU. Additionally, GA-CTS/5-FU significantly inhibited the growth of drug-resistant hepatoma, which may compensate for the drug-resistance of 5-FU. In vivo studies on an orthotropic liver cancer mouse model demonstrated that GA-CTS/5-FU significantly inhibited tumor growth, resulting in increased survival time. Full article

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Open AccessArticle

The Marine Natural Product Manzamine A Targets Vacuolar ATPases and Inhibits Autophagy in Pancreatic Cancer Cells

by Georgios Kallifatidis, Dominic Hoepfner, Tiphaine Jaeg, Esther A. Guzmán and Amy E. Wright

Mar. Drugs 2013, 11(9), 3500-3516; https://doi.org/10.3390/md11093500 - 17 Sep 2013

Cited by 56 | Viewed by 10287 | Correction

Abstract

Manzamine A, a member of the manzamine alkaloids, was originally isolated from marine sponges of the genus Haliclona. It was recently shown to have activity against pancreatic cancer cells, but the precise mechanism of action remained unclear. To further our understanding of the [...] Read more.

Manzamine A, a member of the manzamine alkaloids, was originally isolated from marine sponges of the genus Haliclona. It was recently shown to have activity against pancreatic cancer cells, but the precise mechanism of action remained unclear. To further our understanding of the mechanism of action of manzamine A, chemogenomic profiling in the yeast S. cerevisiae was performed, suggesting that manzamine A is an uncoupler of vacuolar ATPases. Fluorescence microscopy confirmed this effect on yeast vacuoles, where manzamine A produced a phenotype very similar to that of the established v-ATPase inhibitor bafilomycin A1. In pancreatic cancer cells, 10 µM manzamine A affected vacuolar ATPase activity and significantly increased the level of autophagosome marker LC3-II and p62/SQSTM1 as observed by western blot analysis. Treatment with manzamine A in combination with bafilomycin A1 (inhibitor of autophagosome-lysosome fusion) did not change the levels of LC3-II when compared to cells treated with bafilomycin A1 alone, suggesting that manzamine A is a potential inhibitor of autophagy by preventing autophagosome turnover. As autophagy is essential for pancreatic tumor growth, blocking this pathway with manzamine A suggests a promising strategy for the treatment of pancreatic cancer. Full article

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Open AccessArticle

Discovery and Evaluation of Thiazinoquinones as Anti-Protozoal Agents

by Cary F. C. Lam, A. Norrie Pearce, Shen H. Tan, Marcel Kaiser and Brent R. Copp

Mar. Drugs 2013, 11(9), 3472-3499; https://doi.org/10.3390/md11093472 - 9 Sep 2013

Cited by 22 | Viewed by 7400

Abstract

Pure compound screening has identified the dioxothiazino-quinoline-quinone ascidian metabolite ascidiathiazone A (2) to be a moderate growth inhibitor of Trypanosoma brucei rhodesiense (IC₅₀ 3.1 μM) and Plasmodium falciparum (K1 dual drug resistant strain) (IC₅₀ 3.3 μM) while exhibiting low [...] Read more.

Pure compound screening has identified the dioxothiazino-quinoline-quinone ascidian metabolite ascidiathiazone A (2) to be a moderate growth inhibitor of Trypanosoma brucei rhodesiense (IC₅₀ 3.1 μM) and Plasmodium falciparum (K1 dual drug resistant strain) (IC₅₀ 3.3 μM) while exhibiting low levels of cytotoxicity (L6, IC₅₀ 167 μM). A series of C-7 amide and Δ²⁽³⁾ analogues were prepared that explored the influence of lipophilicity and oxidation state on observed anti-protozoal activity and selectivity. Little variation in anti-malarial potency was observed (IC₅₀ 0.62–6.5 μM), and no correlation was apparent between anti-malarial and anti-T. brucei activity. Phenethylamide 7e and Δ²⁽³⁾-glycine analogue 8k exhibited similar anti-Pf activity to 2 but with slightly enhanced selectivity (SI 72 and 93, respectively), while Δ²⁽³⁾-phenethylamide 8e (IC₅₀ 0.67 μM, SI 78) exhibited improved potency and selectivity towards T. brucei rhodesiense compared to the natural product hit. A second series of analogues were prepared that replaced the quinoline ring of 2 with benzofuran or benzothiophene moieties. While esters 10a/10b and 15 were once again found to exhibit cytotoxicity, carboxylic acid analogues exhibited potent anti-Pf activity (IC₅₀ 0.34–0.035 μM) combined with excellent selectivity (SI 560–4000). In vivo evaluation of a furan carboxylic acid analogue against P. berghei was undertaken, demonstrating 85.7% and 47% reductions in parasitaemia with ip or oral dosing respectively. Full article

(This article belongs to the Special Issue Antiprotozoal Marine Natural Products)

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Open AccessReview

Plastids of Marine Phytoplankton Produce Bioactive Pigments and Lipids

by Parisa Heydarizadeh, Isabelle Poirier, Damien Loizeau, Lionel Ulmann, Virginie Mimouni, Benoît Schoefs and Martine Bertrand

Mar. Drugs 2013, 11(9), 3425-3471; https://doi.org/10.3390/md11093425 - 9 Sep 2013

Cited by 87 | Viewed by 13588

Abstract

Phytoplankton is acknowledged to be a very diverse source of bioactive molecules. These compounds play physiological roles that allow cells to deal with changes of the environmental constrains. For example, the diversity of light harvesting pigments allows efficient photosynthesis at different depths in [...] Read more.

Phytoplankton is acknowledged to be a very diverse source of bioactive molecules. These compounds play physiological roles that allow cells to deal with changes of the environmental constrains. For example, the diversity of light harvesting pigments allows efficient photosynthesis at different depths in the seawater column. Identically, lipid composition of cell membranes can vary according to environmental factors. This, together with the heterogenous evolutionary origin of taxa, makes the chemical diversity of phytoplankton compounds much larger than in terrestrial plants. This contribution is dedicated to pigments and lipids synthesized within or from plastids/photosynthetic membranes. It starts with a short review of cyanobacteria and microalgae phylogeny. Then the bioactivity of pigments and lipids (anti-oxidant, anti-inflammatory, anti-mutagenic, anti-cancer, anti-obesity, anti-allergic activities, and cardio- neuro-, hepato- and photoprotective effects), alone or in combination, is detailed. To increase the cellular production of bioactive compounds, specific culture conditions may be applied (e.g., high light intensity, nitrogen starvation). Regardless of the progress made in blue biotechnologies, the production of bioactive compounds is still limited. However, some examples of large scale production are given, and perspectives are suggested in the final section. Full article

(This article belongs to the Collection Bioactive Compounds from Marine Plankton)

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Open AccessArticle

Hippuristanol Reduces the Viability of Primary Effusion Lymphoma Cells both in Vitro and in Vivo

by Chie Ishikawa, Junichi Tanaka, Harutaka Katano, Masachika Senba and Naoki Mori

Mar. Drugs 2013, 11(9), 3410-3424; https://doi.org/10.3390/md11093410 - 6 Sep 2013

Cited by 22 | Viewed by 9042

Abstract

Primary effusion lymphoma (PEL) caused by Kaposi’s sarcoma-associated herpesvirus (also known as human herpesvirus-8) shows serious lymphomatous effusion in body cavities. PEL is difficult to treat and there is no standard treatment strategy. Hippuristanol is extracted from Okinawan coral Isis hippuris, and [...] Read more.

Primary effusion lymphoma (PEL) caused by Kaposi’s sarcoma-associated herpesvirus (also known as human herpesvirus-8) shows serious lymphomatous effusion in body cavities. PEL is difficult to treat and there is no standard treatment strategy. Hippuristanol is extracted from Okinawan coral Isis hippuris, and inhibits translational initiation by blocking eukaryotic initiation factor 4A, an ATP-dependent RNA helicase, binding to mRNA. Recently, there has been much interest in targeting translation initiation as an anticancer therapy. Here, we show that treatment of PEL cell lines with hippuristanol resulted in cell cycle arrest at G₁ phase, and induced caspases activation and apoptosis. Hippuristanol also reduced the expression of cyclin D2, CDK2, CDK4, CDK6 and prosurvival XIAP and Mcl-1 proteins. Activation of activator protein-1, signal transducers and activators of transcription protein 3 and Akt pathways plays a critical role in the survival and growth of PEL cells. Hippuristanol suppressed the activities of these three pathways by inhibiting the expression of JunB, JunD, c-Fos, signal transducers and activators of transcription protein 3 and Akt proteins. In a xenograft mouse model that showed ascites and diffused organ invasion of PEL cells, treatment with hippuristanol significantly inhibited the growth and invasion of PEL cells compared with untreated mice. The results of the in vitro and in vivo experiments underline the potential usefulness of hippuristanol in the treatment of PEL. Full article

(This article belongs to the Collection Marine Compounds and Cancer)

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Open AccessReview

Cephalopods as Vectors of Harmful Algal Bloom Toxins in Marine Food Webs

by Vanessa M. Lopes, Ana Rita Lopes, Pedro Costa and Rui Rosa

Mar. Drugs 2013, 11(9), 3381-3409; https://doi.org/10.3390/md11093381 - 6 Sep 2013

Cited by 47 | Viewed by 13935

Abstract

Here we summarize the current knowledge on the transfer and accumulation of harmful algal bloom (HAB)-related toxins in cephalopods (octopods, cuttlefishes and squids). These mollusks have been reported to accumulate several HAB-toxins, namely domoic acid (DA, and its isomers), saxitoxin (and [...] Read more.

Here we summarize the current knowledge on the transfer and accumulation of harmful algal bloom (HAB)-related toxins in cephalopods (octopods, cuttlefishes and squids). These mollusks have been reported to accumulate several HAB-toxins, namely domoic acid (DA, and its isomers), saxitoxin (and its derivatives) and palytoxin (and palytoxin-like compounds) and, therefore, act as HAB-toxin vectors in marine food webs. Coastal octopods and cuttlefishes store considerably high levels of DA (amnesic shellfish toxin) in several tissues, but mainly in the digestive gland (DG)—the primary site of digestive absorption and intracellular digestion. Studies on the sub-cellular partitioning of DA in the soluble and insoluble fractions showed that nearly all DA (92.6%) is found in the cytosol. This favors the trophic transfer of the toxins since cytosolic substances can be absorbed by predators with greater efficiency. The available information on the accumulation and tissue distribution of DA in squids (e.g., in stranded Humboldt squids, Dosidicus gigas) is scarcer than in other cephalopod groups. Regarding paralytic shellfish toxins (PSTs), these organisms accumulate them at the greatest extent in DG >> kidneys > stomach > branchial hearts > posterior salivary glands > gills. Palytoxins are among the most toxic molecules identified and stranded octopods revealed high contamination levels, with ovatoxin (a palytoxin analogue) reaching 971 μg kg⁻¹ and palytoxin reaching 115 μg kg⁻¹ (the regulatory limit for PlTXs is 30 μg kg⁻¹ in shellfish). Although the impacts of HAB-toxins in cephalopod physiology are not as well understood as in fish species, similar effects are expected since they possess a complex nervous system and highly developed brain comparable to that of the vertebrates. Compared to bivalves, cephalopods represent a lower risk of shellfish poisoning in humans, since they are usually consumed eviscerated, with exception of traditional dishes from the Mediterranean area. Full article

(This article belongs to the Special Issue Marine Shellfish Toxins)

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Open AccessCommunication

Secondary Metabolites from the Soft Coral Sinularia arborea

by Kuan-Hua Chen, Chang-Feng Dai, Mei-Chin Lu, Jan-Jung Li, Jih-Jung Chen, Yu-Chia Chang, Yin-Di Su, Wei-Hsien Wang and Ping-Jyun Sung

Mar. Drugs 2013, 11(9), 3372-3380; https://doi.org/10.3390/md11093372 - 3 Sep 2013

Cited by 19 | Viewed by 6377

Abstract

Previous studies on the chemical constituents of soft corals belonging to the genus Sinularia have led to the isolation of a number of interesting secondary metabolites and some of these were found to possess extensive bioactivities [1–3]. Continuation investigation on the chemical constituents [...] Read more.

Previous studies on the chemical constituents of soft corals belonging to the genus Sinularia have led to the isolation of a number of interesting secondary metabolites and some of these were found to possess extensive bioactivities [1–3]. Continuation investigation on the chemical constituents of the marine invertebrates collected off the waters of Taiwan, two new cembrane-type diterpenoids, arbolides A (1) and B (2), and a known steroid, crassarosterol A (3) [4], were isolated from the soft coral Sinularia arborea (family Alcyonacea) (Figure 1). In this paper, we describe the isolation, structure determination and cytotoxicity of compounds 1–3. Full article

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Open AccessArticle

Cytotoxicity, Fractionation and Dereplication of Extracts of the Dinoflagellate Vulcanodinium rugosum, a Producer of Pinnatoxin G

by Marie Geiger, Gwenaëlle Desanglois, Kevin Hogeveen, Valérie Fessard, Thomas Leprêtre, Florence Mondeguer, Yann Guitton, Fabienne Hervé, Véronique Séchet, Olivier Grovel, Yves-François Pouchus and Philipp Hess

Mar. Drugs 2013, 11(9), 3350-3371; https://doi.org/10.3390/md11093350 - 2 Sep 2013

Cited by 12 | Viewed by 7990

Abstract

Pinnatoxin G (PnTX-G) is a marine toxin belonging to the class of cyclic imines and produced by the dinoflagellate Vulcanodinium rugosum. In spite of its strong toxicity to mice, leading to the classification of pinnatoxins into the class of “fast-acting toxins”, its [...] Read more.

Pinnatoxin G (PnTX-G) is a marine toxin belonging to the class of cyclic imines and produced by the dinoflagellate Vulcanodinium rugosum. In spite of its strong toxicity to mice, leading to the classification of pinnatoxins into the class of “fast-acting toxins”, its hazard for human health has never been demonstrated. In this study, crude extracts of V. rugosum exhibited significant cytotoxicity against Neuro2A and KB cells. IC₅₀ values of 0.38 µg mL⁻¹ and 0.19 µg mL⁻¹ were estimated on Neuro2A cells after only 24 h of incubation and on KB cells after 72 h of incubation, respectively. In the case of Caco-2 cells 48 h after exposure, the crude extract of V. rugosum induced cell cycle arrest accompanied by a dramatic increase in double strand DNA breaks, although only 40% cytotoxicity was observed at the highest concentration tested (5 µg mL⁻¹). However, PnTX-G was not a potent cytotoxic compound as no reduction of the cell viability was observed on the different cell lines. Moreover, no effects on the cell cycle or DNA damage were observed following treatment of undifferentiated Caco-2 cells with PnTX-G. The crude extract of V. rugosum was thus partially purified using liquid-liquid partitioning and SPE clean-up. In vitro assays revealed strong activity of some fractions containing no PnTX-G. The crude extract and the most potent fraction were evaluated using full scan and tandem high resolution mass spectrometry. The dereplication revealed the presence of a major compound that could be putatively annotated as nakijiquinone A, N-carboxy-methyl-smenospongine or stachybotrin A, using the MarinLit™ database. Further investigations will be necessary to confirm the identity of the compounds responsible for the cytotoxicity and genotoxicity of the extracts of V. rugosum. Full article

(This article belongs to the Special Issue Marine Shellfish Toxins)

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Open AccessArticle

Pharmacological Studies of Tentacle Extract from the Jellyfish Cyanea capillata in Isolated Rat Aorta

by Beilei Wang, Bo Zhang, Qianqian Wang, Zhi Zhang, Fei Nie, Guoyan Liu, Jiemin Zheng, Liang Xiao and Liming Zhang

Mar. Drugs 2013, 11(9), 3335-3349; https://doi.org/10.3390/md11093335 - 30 Aug 2013

Cited by 8 | Viewed by 6956

Abstract

Our previous studies demonstrated that tentacle extract (TE) from the jellyfish, Cyanea capillata, could cause a dose-dependent increase of systolic blood pressure, which seemed to be the result of direct constriction of vascular smooth muscle (VSM). The aim of this study is [...] Read more.

Our previous studies demonstrated that tentacle extract (TE) from the jellyfish, Cyanea capillata, could cause a dose-dependent increase of systolic blood pressure, which seemed to be the result of direct constriction of vascular smooth muscle (VSM). The aim of this study is to investigate whether TE could induce vasoconstriction in vitro and to explore its potential mechanism. Using isolated aorta rings, a direct contractile response of TE was verified, which showed that TE could induce concentration-dependent contractile responses in both endothelium-intact and -denuded aortas. Interestingly, the amplitude of contraction in the endothelium-denuded aorta was much stronger than that in the endothelium-intact one, implying that TE might also bring a weak functional relaxation in addition to vasoconstriction. Further drug intervention experiments indicated that the functional vasodilation might be mediated by nitric oxide, and that TE-induced vasoconstriction could be attributed to calcium influx via voltage-operated calcium channels (VOCCs) from the extracellular space, as well as sarcoplasmic reticulum (SR) Ca²⁺ release via the inositol 1,4,5-trisphosphate receptor (IP₃R), leading to an increase in [Ca²⁺]_c, instead of activation of the PLC/DAG/PKC pathway or the sympathetic nerve system. Full article

(This article belongs to the Special Issue Cytogenetic and Molecular Effects of Marine Compounds)

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Open AccessArticle

The Effect of Low-Dose Marine n-3 Fatty Acids on Plasma Levels of sCD36 in Overweight Subjects: A Randomized, Double-Blind, Placebo-Controlled Trial

by Stine Krogh Venø, Michael René Skjelbo Nielsen, Søren Lundbye-Christensen, Erik Berg Schmidt and Aase Handberg

Mar. Drugs 2013, 11(9), 3324-3334; https://doi.org/10.3390/md11093324 - 30 Aug 2013

Cited by 8 | Viewed by 6237

Abstract

CD36 is a scavenger receptor involved in lipid uptake and inflammation. Recently, non-cell-bound CD36 (sCD36) was identified in plasma and suggested to be a marker of lipid accumulation in the vessel wall. Marine n-3 polyunsaturated fatty acids (PUFA) may have cardioprotective effects. [...] Read more.

CD36 is a scavenger receptor involved in lipid uptake and inflammation. Recently, non-cell-bound CD36 (sCD36) was identified in plasma and suggested to be a marker of lipid accumulation in the vessel wall. Marine n-3 polyunsaturated fatty acids (PUFA) may have cardioprotective effects. This study evaluated the effect of marine n-3 PUFA on sCD36 levels in overweight subjects. Fifty overweight subjects were randomized to 1.1 g of n-3 PUFA or 2 g of olive oil daily for six weeks. Neutrophils were isolated at baseline and after six weeks of treatment while an adipose tissue biopsy was obtained at baseline. The content of n-3 PUFA in adipose tissue and neutrophils was analyzed by gas chromatography, while plasma levels of sCD36 were determined using an enzyme-linked immunosorbent assay (ELISA). After six weeks of supplement plasma sCD36 did not differ between supplements (P = 0.18). There was no significant correlation between plasma sCD36 levels and n-3 PUFA in neutrophils at baseline (r = −0.02, P = 0.88), after six weeks supplement (r = −0.03, P = 0.85) or in adipose tissue (r = 0.14, P = 0.34). This study therefore does not provide evidence for a cardioprotective effect of n-3 PUFA acting through a CD36-dependent mechanism. Full article

(This article belongs to the Special Issue Marine Fatty Acids-2013)

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Open AccessArticle

Calcarides A–E, Antibacterial Macrocyclic and Linear Polyesters from a Calcarisporium Strain

by Johanna Silber, Birgit Ohlendorf, Antje Labes, Arlette Erhard and Johannes F. Imhoff

Mar. Drugs 2013, 11(9), 3309-3323; https://doi.org/10.3390/md11093309 - 29 Aug 2013

Cited by 43 | Viewed by 7399

Abstract

Bioactive compounds were detected in crude extracts of the fungus, Calcarisporium sp. KF525, which was isolated from German Wadden Sea water samples. Purification of the metabolites from the extracts yielded the five known polyesters, 15G256α, α-2, β, β-2 and π (1– [...] Read more.

Bioactive compounds were detected in crude extracts of the fungus, Calcarisporium sp. KF525, which was isolated from German Wadden Sea water samples. Purification of the metabolites from the extracts yielded the five known polyesters, 15G256α, α-2, β, β-2 and π (1–5), and five new derivatives thereof, named calcarides A–E (6–10). The chemical structures of the isolated compounds were elucidated on the basis of one- and two-dimensional NMR spectroscopy supported by UV and HRESIMS data. The compounds exhibited inhibitory activities against Staphylococcus epidermidis, Xanthomonas campestris and Propionibacterium acnes. As the antibacterial activities were highly specific with regard to compound and test strain, a tight structure-activity relationship is assumed. Full article

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Open AccessArticle

Natural and Semisynthetic Analogues of Manadoperoxide B Reveal New Structural Requirements for Trypanocidal Activity

by Giuseppina Chianese, Fernando Scala, Barbara Calcinai, Carlo Cerrano, Henny A. Dien, Marcel Kaiser, Deniz Tasdemir and Orazio Taglialatela-Scafati

Mar. Drugs 2013, 11(9), 3297-3308; https://doi.org/10.3390/md11093297 - 28 Aug 2013

Cited by 14 | Viewed by 6970

Abstract

Chemical analysis of the Indonesian sponge Plakortis cfr. lita afforded two new analogues of the potent trypanocidal agent manadoperoxide B (1), namely 12-isomanadoperoxide B (2) and manadoperoxidic acid B (3). These compounds were isolated along with [...] Read more.

Chemical analysis of the Indonesian sponge Plakortis cfr. lita afforded two new analogues of the potent trypanocidal agent manadoperoxide B (1), namely 12-isomanadoperoxide B (2) and manadoperoxidic acid B (3). These compounds were isolated along with a new short chain dicarboxylate monoester (4), bearing some interesting relationships with the polyketide endoperoxides found in this sponge. Some semi-synthetic analogues of manadoperoxide B (6–8) were prepared and evaluated for antitrypanosomal activity and cytotoxicity. These studies revealed crucial structure–activity relationships that should be taken into account in the design of optimized and simplified endoperoxyketal trypanocidal agents. Full article

(This article belongs to the Special Issue Antiprotozoal Marine Natural Products)

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Open AccessArticle

Secosteroids and Norcembranoids from the Soft Coral Sinularia nanolobata

by Yen-Ju Tseng, Shang-Kwei Wang and Chang-Yih Duh

Mar. Drugs 2013, 11(9), 3288-3296; https://doi.org/10.3390/md11093288 - 27 Aug 2013

Cited by 26 | Viewed by 6958

Abstract

Two new 9,11-secosteroids, 22α-acetoxy-24-methylene-3β,6α,11-trihydroxy-9, 11-seco-cholest-7-en-9-one (1) and 11-acetoxy-24-methylene-1β,3β,6α-trihydroxy-9, 11-seco-cholest-7-en-9-one (2), as well as two known norcembranoids, 5-epi-sinuleptolide (3) and sinuleptolide (4), were isolated from the soft coral Sinularia nanolobata. The structures of [...] Read more.

Two new 9,11-secosteroids, 22α-acetoxy-24-methylene-3β,6α,11-trihydroxy-9, 11-seco-cholest-7-en-9-one (1) and 11-acetoxy-24-methylene-1β,3β,6α-trihydroxy-9, 11-seco-cholest-7-en-9-one (2), as well as two known norcembranoids, 5-epi-sinuleptolide (3) and sinuleptolide (4), were isolated from the soft coral Sinularia nanolobata. The structures of these metabolites were elucidated on the basis of extensive spectroscopic analysis. The anti-HCMV (human cytomegalovirus) activity of 1–4 and its cytotoxicity against selected cell lines were evaluated. Full article

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Open AccessArticle

Apo-9′-Fucoxanthinone, Isolated from Sargassum muticum, Inhibits CpG-Induced Inflammatory Response by Attenuating the Mitogen-Activated Protein Kinase Pathway

by Doobyeong Chae, Zahid Manzoor, Sung Chun Kim, Sohyun Kim, Tae-Heon Oh, Eun-Sook Yoo, Hee-Kyoung Kang, Jin-Won Hyun, Nam Ho Lee, Mi-Hee Ko and Young-Sang Koh

Mar. Drugs 2013, 11(9), 3272-3287; https://doi.org/10.3390/md11093272 - 27 Aug 2013

Cited by 37 | Viewed by 8299

Abstract

Sargassum muticum (S. muticum) is a brown edible alga and widely distributed in Korea. This report was designed to evaluate the anti-inflammatory properties of apo-9′-fucoxanthinone (APO-9′) isolated from S. muticum on pro-inflammatory cytokine production. S. muticum extract (SME) exhibited significant [...] Read more.

Sargassum muticum (S. muticum) is a brown edible alga and widely distributed in Korea. This report was designed to evaluate the anti-inflammatory properties of apo-9′-fucoxanthinone (APO-9′) isolated from S. muticum on pro-inflammatory cytokine production. S. muticum extract (SME) exhibited significant inhibitory effects on pro-inflammatory cytokine production in bone marrow-derived macrophages (BMDMs) and dendritic cells (BMDCs). APO-9′ pre-treatment in the CpG DNA-stimulated BMDMs and BMDCs showed a strong dose-dependent inhibitory effect on interleukin (IL)-12 p40, IL-6 and tumor necrosis factor (TNF)-α production with IC₅₀ values ranging from 5.31 to 13.79. It exhibited a strong inhibitory effect on the phosphorylation of ERK1/2 and on activator protein (AP)-1 reporter activity. APO-9′ pre-treatment exhibited significant inhibition of CpG DNA-induced production of inducible nitric oxide synthase. Taken together, these data suggest that SME and APO-9′ have a significant anti-inflammatory property and warrant further studies concerning the potentials of SME and APO-9′ for medicinal use. Full article

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Open AccessArticle

Cyclodextrin Formulation of the Marine Natural Product Pseudopterosin A Uncovers Optimal Pharmacodynamics in Proliferation Studies of Human Umbilical Vein Endothelial Cells

by Daniel R. Day, Suraya Jabaiah, Robert S. Jacobs and R. Daniel Little

Mar. Drugs 2013, 11(9), 3258-3271; https://doi.org/10.3390/md11093258 - 26 Aug 2013

Cited by 14 | Viewed by 8522

Abstract

Pseudopterosin A (PsA) treatment of growth factor depleted human umbilical vein endothelial cell (HUVEC) cultures formulated in hydroxypropyl-β-cyclodextrin (HPβCD) for 42 h unexpectedly produced a 25% increase in cell proliferation (EC₅₀ = 1.34 × 10⁻⁸ M). Analysis of dose response curves [...] Read more.

Pseudopterosin A (PsA) treatment of growth factor depleted human umbilical vein endothelial cell (HUVEC) cultures formulated in hydroxypropyl-β-cyclodextrin (HPβCD) for 42 h unexpectedly produced a 25% increase in cell proliferation (EC₅₀ = 1.34 × 10⁻⁸ M). Analysis of dose response curves revealed pseudo-first order saturation kinetics, and the uncoupling of cytotoxicity from cell proliferation, thereby resulting in a widening of the therapeutic index. The formulation of PsA into HPβCD produced a 200-fold increase in potency over a DMSO formulation; we propose this could result from a constrained presentation of PsA to the receptor, which would limit non-specific binding. These results support the hypothesis that the non-specific receptor binding of PsA when formulated in DMSO has ostensibly masked prior estimates of specific activity, potency, and mechanism. Collectively, these results suggest that the formulation of PsA and compounds of similar chemical properties in HPβCD could result in significant pharmacological findings that may otherwise be obscured when using solvents such as DMSO. Full article

(This article belongs to the Special Issue Marine Secondary Metabolites)

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Open AccessArticle

Epigonal Conditioned Media from Bonnethead Shark, Sphyrna tiburo, Induces Apoptosis in a T-Cell Leukemia Cell Line, Jurkat E6-1

by Catherine J. Walsh, Carl A. Luer, Jennifer E. Yordy, Theresa Cantu, Jodi Miedema, Stephanie R. Leggett, Brittany Leigh, Philip Adams, Marissa Ciesla, Courtney Bennett and Ashby B. Bodine

Mar. Drugs 2013, 11(9), 3224-3257; https://doi.org/10.3390/md11093224 - 26 Aug 2013

Cited by 10 | Viewed by 10875

Abstract

Representatives of Subclass Elasmobranchii are cartilaginous fish whose members include sharks, skates, and rays. Because of their unique phylogenetic position of being the most primitive group of vertebrates to possess all the components necessary for an adaptive immune system, the immune regulatory compounds [...] Read more.

Representatives of Subclass Elasmobranchii are cartilaginous fish whose members include sharks, skates, and rays. Because of their unique phylogenetic position of being the most primitive group of vertebrates to possess all the components necessary for an adaptive immune system, the immune regulatory compounds they possess may represent the earliest evolutionary forms of novel compounds with the potential for innovative therapeutic applications. Conditioned medium, generated from short term culture of cells from the epigonal organ of bonnethead sharks (Sphyrna tiburo), has been shown to have potent reproducible cytotoxic activity against a variety of human tumor cell lines in vitro. Existing data suggest that epigonal conditioned medium (ECM) exerts this cytotoxic activity through induction of apoptosis in target cells. This manuscript describes apoptosis induction in a representative tumor cell line, Jurkat E6-1, in response to treatment with ECM at concentrations of 1 and 2 mg/mL. Data indicate that ECM exposure initiates the mitochondrial pathway of apoptosis through activation of caspase enzymes. Future purification of ECM components may result in the isolation of an immune-regulatory compound with potential therapeutic benefit for treatment of human cancer. Full article

(This article belongs to the Collection Marine Compounds and Cancer)

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Marine Derived Hamacanthins as Lead for the Development of Novel PDGFRβ Protein Kinase Inhibitors

by Boris Pinchuk, Eugen Johannes, Sheraz Gul, Joachim Schlosser, Christoph Schaechtele, Frank Totzke and Christian Peifer

Mar. Drugs 2013, 11(9), 3209-3223; https://doi.org/10.3390/md11093209 - 26 Aug 2013

Cited by 11 | Viewed by 7769

Abstract

In this study, we report on pyrazin-2(1H)-ones as lead for the development of potent adenosine triphosphate (ATP) competitive protein kinase inhibitors with implications as anti-cancer drugs. Initially, we identified the pyrazin-2(1H)-one scaffold from hamacanthins (deep sea marine sponge alkaloids) [...] Read more.

In this study, we report on pyrazin-2(1H)-ones as lead for the development of potent adenosine triphosphate (ATP) competitive protein kinase inhibitors with implications as anti-cancer drugs. Initially, we identified the pyrazin-2(1H)-one scaffold from hamacanthins (deep sea marine sponge alkaloids) by Molecular Modeling studies as core binding motif in the ATP pocket of receptor tyrosine kinases (RTK), which are validated drug targets for the treatment of various neoplastic diseases. Structure-based design studies on a human RTK member PDGFR (platelet-derived growth factor receptor) suggested a straight forward lead optimization strategy. Accordingly, we focused on a Medicinal Chemistry project to develop pyrazin-2(1H)-ones as optimized PDGFR binders. In order to reveal Structure-Activity-Relationships (SAR), we established a flexible synthetic route via microwave mediated ring closure to asymmetric 3,5-substituted pyrazin-2(1H)-ones and produced a set of novel compounds. Herein, we identified highly potent PDGFR binders with IC₅₀ values in an enzymatic assay below µM range, and possessing significant activity against PDGFR dependent cancer cells. Thus, marine hamacanthin-derived pyrazin-2(1H)-ones showing interesting properties as lead for their further development towards potent PDGFR-inhibitors. Full article

(This article belongs to the Special Issue Marine Compounds as Protein Kinase Inhibitors)

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Open AccessArticle

Influence of Lipid A Acylation Pattern on Membrane Permeability and Innate Immune Stimulation

by Yanyan Li, Zhou Wang, Jiuzhou Chen, Robert K. Ernst and Xiaoyuan Wang

Mar. Drugs 2013, 11(9), 3197-3208; https://doi.org/10.3390/md11093197 - 26 Aug 2013

Cited by 43 | Viewed by 8725

Abstract

Lipid A, the hydrophobic anchor of lipopolysaccharide (LPS), is an essential component in the outer membrane of Gram-negative bacteria. It can stimulate the innate immune system via Toll-like receptor 4/myeloid differentiation factor 2 (TLR4/MD2), leading to the release of inflammatory cytokines. In this [...] Read more.

Lipid A, the hydrophobic anchor of lipopolysaccharide (LPS), is an essential component in the outer membrane of Gram-negative bacteria. It can stimulate the innate immune system via Toll-like receptor 4/myeloid differentiation factor 2 (TLR4/MD2), leading to the release of inflammatory cytokines. In this study, six Escherichia coli strains which can produce lipid A with different acylation patterns were constructed; the influence of lipid A acylation pattern on the membrane permeability and innate immune stimulation has been systematically investigated. The lipid A species were isolated and identified by matrix assisted laser ionization desorption-time of flight/tandem mass spectrometry. N-Phenyl naphthylamine uptake assay and antibiotic susceptibility test showed that membrane permeability of these strains were different. The lower the number of acyl chains in lipid A, the stronger the membrane permeability. LPS purified from these strains were used to stimulate human or mouse macrophage cells, and different levels of cytokines were induced. Compared with wild type hexa-acylated LPS, penta-acylated, tetra-acylated and tri-acylated LPS induced lower levels of cytokines. These results suggest that the lipid A acylation pattern influences both the bacterial membrane permeability and innate immune stimulation. The results would be useful for redesigning the bacterial membrane structure and for developing lipid A vaccine adjuvant. Full article

(This article belongs to the Special Issue Marine Lipopolysaccharides)

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Open AccessArticle

Sarcophyolides B–E, New Cembranoids from the Soft Coral Sarcophyton elegans

by Zhifang Xi, Wei Bie, Wei Chen, Dong Liu, Leen Van Ofwegen, Peter Proksch and Wenhan Lin

Mar. Drugs 2013, 11(9), 3186-3196; https://doi.org/10.3390/md11093186 - 26 Aug 2013

Cited by 45 | Viewed by 7466

Abstract

Four new cembrane-type diterpenoids, sarcophyolides B–E (1–4), along with 11 known analogues were isolated from the soft coral Sarcophyton elegans. The structures of new compounds 1–4 were established on the basis of spectroscopic analysis and chemical [...] Read more.

Four new cembrane-type diterpenoids, sarcophyolides B–E (1–4), along with 11 known analogues were isolated from the soft coral Sarcophyton elegans. The structures of new compounds 1–4 were established on the basis of spectroscopic analysis and chemical conversion. The new cembranoids sarcophyolides B (1) and lobocrasol were found to exhibit potent inhibition against A2780 human ovarian tumor cells. Full article

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Towards the Small and the Beautiful: A Small Dibromotyrosine Derivative from Pseudoceratina sp. Sponge Exhibits Potent Apoptotic Effect through Targeting IKK/NFκB Signaling Pathway

by Jui-Hsin Su, Yu-Cheng Chen, Mohamed El-Shazly, Ying-Chi Du, Chiang-Wen Su, Chia-Wei Tsao, Li-Lian Liu, Yalan Chou, Wen-Been Chang, Yin-Di Su, Michael Y. Chiang, Yao-Tsung Yeh and Mei-Chin Lu

Mar. Drugs 2013, 11(9), 3168-3185; https://doi.org/10.3390/md11093168 - 26 Aug 2013

Cited by 34 | Viewed by 7909

Abstract

A dibromotyrosine derivative, (1′R,5′S,6′S)-2-(3′,5′-dibromo-1′,6′-dihydroxy-4′-oxocyclohex-2′-enyl) acetonitrile (DT), was isolated from the sponge Pseudoceratina sp., and was found to exhibit a significant cytotoxic activity against leukemia K562 cells. Despite the large number of the isolated bromotyrosine derivatives, studies focusing [...] Read more.

A dibromotyrosine derivative, (1′R,5′S,6′S)-2-(3′,5′-dibromo-1′,6′-dihydroxy-4′-oxocyclohex-2′-enyl) acetonitrile (DT), was isolated from the sponge Pseudoceratina sp., and was found to exhibit a significant cytotoxic activity against leukemia K562 cells. Despite the large number of the isolated bromotyrosine derivatives, studies focusing on their biological mechanism of action are scarce. In the current study we designed a set of experiments to reveal the underlying mechanism of DT cytotoxic activity against K562 cells. First, the results of MTT cytotoxic and the annexin V-FITC/PI apoptotic assays, indicated that the DT cytotoxic activity is mediated through induction of apoptosis. This effect was also supported by caspases-3 and -9 activation as well as PARP cleavage. DT induced generation of reactive oxygen species (ROS) and the disruption of mitochondrial membrane potential (MMP) as indicated by flow cytometric assay. The involvement of ROS generation in the apoptotic activity of DT was further corroborated by the pretreatment of K562 cells with N-acetyl-cysteine (NAC), a ROS scavenger, which prevented apoptosis and the disruption of MMP induced by DT. Results of cell-free system assay suggested that DT can act as a topoisomerase II catalytic inhibitor, unlike the clinical anticancer drug, etoposide, which acts as a topoisomerase poison. Additionally, we found that DT treatment can block IKK/NFκB pathway and activate PI3K/Akt pathway. These findings suggest that the cytotoxic effect of DT is associated with mitochondrial dysfunction-dependent apoptosis which is mediated through oxidative stress. Therefore, DT represents an interesting reference point for the development of new cytotoxic agent targeting IKK/NFκB pathway. Full article

(This article belongs to the Collection Marine Compounds and Cancer)

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Open AccessReview

Silaffins of Diatoms: From Applied Biotechnology to Biomedicine

by Igor E. Pamirsky and Kirill S. Golokhvast

Mar. Drugs 2013, 11(9), 3155-3167; https://doi.org/10.3390/md11093155 - 26 Aug 2013

Cited by 44 | Viewed by 8103

Abstract

Silaffins are involved in the formation of the cell walls of diatoms. It is known that silaffins can precipitate silica in vitro, forming nano- and micro-particles in the shape of spheres and plates containing many pores. It is important to note that [...] Read more.

Silaffins are involved in the formation of the cell walls of diatoms. It is known that silaffins can precipitate silica in vitro, forming nano- and micro-particles in the shape of spheres and plates containing many pores. It is important to note that the deposition of silica and the particle morphology in the presence of silaffins affects chemical and physical agents (e.g., peptides, polyamines, phosphate, nitrogen, and the mechanical changes of the reaction mixture). It is believed that silaffins act as an organic matrix for silica-genesis and that silica pore size should reflect the pattern of a matrix. Here, biotechnology related to silaffins is discussed in the context of “a hypothesis of silaffin matrix” and “the LCPA-phosphate model”. We discuss the most promising area of silaffin biotechnology—the development of production methods for silicon structures with desired shapes and nanostructural properties that can be used to create biocompatible materials. Full article

(This article belongs to the Special Issue Selected Papers from the 1st Symposium on Marine Enzymes and Polysaccharides)

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Glycosylated Porphyra-334 and Palythine-Threonine from the Terrestrial Cyanobacterium Nostoc commune

by Ehsan Nazifi, Naoki Wada, Minami Yamaba, Tomoya Asano, Takumi Nishiuchi, Seiichi Matsugo and Toshio Sakamoto

Mar. Drugs 2013, 11(9), 3124-3154; https://doi.org/10.3390/md11093124 - 26 Aug 2013

Cited by 59 | Viewed by 9988

Abstract

Mycosporine-like amino acids (MAAs) are water-soluble UV-absorbing pigments, and structurally different MAAs have been identified in eukaryotic algae and cyanobacteria. In this study novel glycosylated MAAs were found in the terrestrial cyanobacterium Nostoc commune (N. commune). An MAA with an absorption [...] Read more.

Mycosporine-like amino acids (MAAs) are water-soluble UV-absorbing pigments, and structurally different MAAs have been identified in eukaryotic algae and cyanobacteria. In this study novel glycosylated MAAs were found in the terrestrial cyanobacterium Nostoc commune (N. commune). An MAA with an absorption maximum at 334 nm was identified as a hexose-bound porphyra-334 derivative with a molecular mass of 508 Da. Another MAA with an absorption maximum at 322 nm was identified as a two hexose-bound palythine-threonine derivative with a molecular mass of 612 Da. These purified MAAs have radical scavenging activities in vitro, which suggests multifunctional roles as sunscreens and antioxidants. The 612-Da MAA accounted for approximately 60% of the total MAAs and contributed approximately 20% of the total radical scavenging activities in a water extract, indicating that it is the major water-soluble UV-protectant and radical scavenger component. The hexose-bound porphyra-334 derivative and the glycosylated palythine-threonine derivatives were found in a specific genotype of N. commune, suggesting that glycosylated MAA patterns could be a chemotaxonomic marker for the characterization of the morphologically indistinguishable N. commune. The glycosylation of porphyra-334 and palythine-threonine in N. commune suggests a unique adaptation for terrestrial environments that are drastically fluctuating in comparison to stable aquatic environments. Full article

(This article belongs to the Special Issue Compounds from Cyanobacteria)

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Pachydictyols B and C: New Diterpenes from Dictyota dichotoma Hudson

by Ghada S. E. Abou-El-Wafa, Mohamed Shaaban, Khaled A. Shaaban, Mohamed E. E. El-Naggar, Armin Maier, Heinz H. Fiebig and Hartmut Laatsch

Mar. Drugs 2013, 11(9), 3109-3123; https://doi.org/10.3390/md11093109 - 22 Aug 2013

Cited by 28 | Viewed by 7562

Abstract

Two new diterpenoids, pachydictyol B (1a/1b) and C (2), were isolated from the dichloromethane extract of the marine brown alga, Dictyota dichotoma, collected from the Red Sea coast of Egypt, along with the known metabolites, pachydictyol [...] Read more.

Two new diterpenoids, pachydictyol B (1a/1b) and C (2), were isolated from the dichloromethane extract of the marine brown alga, Dictyota dichotoma, collected from the Red Sea coast of Egypt, along with the known metabolites, pachydictyol A (3a), dictyol E (4), cis-africanan-1α-ol (5a), fucosterol (6), tetrahydrothiophen-1,1-dioxide and poly-β-hydroxybutyric acid. GC-MS analysis of the nonpolar fractions also indicated the presence of β-bourbonene and nonanal, along with three hydrocarbons and five fatty acids or their simple derivatives, respectively. GC-MS analysis of the unsaponifiable algal petroleum ether extract revealed the presence of a further eight compounds, among them 2,2,6,7-tetramethyl-10-oxatricyclo[4.3.0.1(1,7)]decan-5-one (7), N-(4-bromo-n-butyl)-pipe ridin-2-one (8) and tert-hexadecanethiol. Structures 1–6 were assigned by 1D and 2D NMR, mass spectra (EI, CI, HREI and HRESI) and by comparison with data from related structures. The crude algal extract was potently active against the breast carcinoma tumor cell line, MCF7 (IC₅₀ = 0.6 µg mL⁻¹); pachydictyol B (1a) and dictyol E (4) showed weak antimicrobial properties, and the other compounds were inactive. Pachydictyols B (1a) and C (2) demonstrated a weak and unselective cytotoxicity against twelve human tumor cell lines with a mean IC₅₀ of >30.0 µM. Full article

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Mar. Drugs, Volume 11, Issue 9 (September 2013) – 26 articles , Pages 3109-3581

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