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Mar. Drugs, Volume 12, Issue 2 (February 2014), Pages 568-1168

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Editorial

Jump to: Research, Review

Open AccessEditorial Marine Drugs Best Paper Award 2014
Mar. Drugs 2014, 12(2), 1157-1159; doi:10.3390/md12021157
Received: 27 January 2014 / Accepted: 13 February 2014 / Published: 21 February 2014
Cited by 1 | PDF Full-text (354 KB) | HTML Full-text | XML Full-text
Abstract
Marine Drugs initiated a “Best Paper Award” in 2013 [1] to recognize outstanding papers published in our journal in the area of research, development and production of drugs from the sea, including marine natural product chemistry. We are pleased to announce the second
[...] Read more.
Marine Drugs initiated a “Best Paper Award” in 2013 [1] to recognize outstanding papers published in our journal in the area of research, development and production of drugs from the sea, including marine natural product chemistry. We are pleased to announce the second “Marine Drugs Best Paper Award” for 2014. Nominations were selected by the Editor-in-Chief, Associate Editors and Editorial Board Members of Marine Drugs from all papers published in 2010; reviews and articles being evaluated separately. [...] Full article
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Open AccessEditorial Acknowledgement to Reviewers of Marine Drugs in 2013
Mar. Drugs 2014, 12(2), 1160-1168; doi:10.3390/md12021160
Received: 20 February 2014 / Accepted: 24 February 2014 / Published: 24 February 2014
PDF Full-text (421 KB) | HTML Full-text | XML Full-text
Abstract The editors of Marine Drugs would like to express their sincere gratitude to the following reviewers for assessing manuscripts in 2013 [...] Full article

Research

Jump to: Editorial, Review

Open AccessArticle Anti-Inflammatory Activity and Mechanism of a Lipid Extract from Hard-Shelled Mussel (Mytilus Coruscus) on Chronic Arthritis in Rats
Mar. Drugs 2014, 12(2), 568-588; doi:10.3390/md12020568
Received: 13 November 2013 / Revised: 9 December 2013 / Accepted: 13 January 2014 / Published: 27 January 2014
Cited by 6 | PDF Full-text (782 KB) | HTML Full-text | XML Full-text
Abstract
The present study was designed to investigate the anti-inflammatory activity and mechanism of a lipid extract from hard-shelled mussel (Mytilus coruscus) on adjuvant-induced (AIA) and collagen-induced arthritis (CIA) in rats. AIA and CIA rats that received hard-shelled mussel lipid extract (HMLE
[...] Read more.
The present study was designed to investigate the anti-inflammatory activity and mechanism of a lipid extract from hard-shelled mussel (Mytilus coruscus) on adjuvant-induced (AIA) and collagen-induced arthritis (CIA) in rats. AIA and CIA rats that received hard-shelled mussel lipid extract (HMLE group) at a dose of 100 mg/kg demonstrated significantly lower paw swelling and arthritic index, but higher body weight gain than those which received olive oil (control group). Similar results were found in arthritic rats that received New Zealand green-lipped mussel lipid extract (GMLE) at the same dosage. The levels of leukotriene B4 (LTB4), prostaglandin E2 (PGE2), thromboxane B2 (TXB2) in the serum, and interleukin-1β (IL-1β), IL-6, interferon-γ (INF-γ), tumor necrosis factor-α (TNF-α) in the ankle joint synovial fluids of HMLE group rats were significantly lower than those of control group. However, the levels of IL-4 and IL-10 in HMLE group rats were significantly higher than those in the control group. Decreased mRNA expressions of matrix metalloproteinase 1 (MMP1) and MMP13, but increased tissue inhibitor of metalloproteinase 1 (TIMP1) were observed in the knee joint synovium tissues of HMLE group rats when compared with the control group. No hepatotoxicity was observed in both HMLE and GMLE group rats. The present results indicated that HMLE had a similarly strong anti-inflammatory activity as GMLE. Such a strong efficacy could result from the suppression of inflammatory mediators (LTB4, PGE2, TXB2), pro-inflammatory cytokines (IL-1β, IL-6, INF-γ, TNF-α) and MMPs (MMP1, MMP13), and the promotion of anti-inflammatory cytokines (IL-4, IL-10) and TIMPs (TIMP1) productions. Full article
(This article belongs to the Special Issue Marine Fatty Acids-2013)
Open AccessArticle Briarane Diterpenes from the South China Sea Gorgonian Coral, Junceella gemmacea
Mar. Drugs 2014, 12(2), 589-600; doi:10.3390/md12020589
Received: 12 December 2013 / Revised: 13 January 2014 / Accepted: 15 January 2014 / Published: 27 January 2014
Cited by 4 | PDF Full-text (833 KB) | HTML Full-text | XML Full-text
Abstract
Four new briarane diterpenoids, junceellolides M–P (14), were isolated together with seven known analogs (511) from the South China Sea gorgonian, Junceella gemmacea. The structures of these compounds were elucidated by detailed spectroscopic analysis
[...] Read more.
Four new briarane diterpenoids, junceellolides M–P (14), were isolated together with seven known analogs (511) from the South China Sea gorgonian, Junceella gemmacea. The structures of these compounds were elucidated by detailed spectroscopic analysis and comparison with the reported data. The absolute configuration of compounds 13 were determined based on an ECD experiment, while the absolute configuration of compound 4 was genetically determined. All the compounds were isolated for the first time from J. gemmacea. These compounds showed no growth inhibitory activity against A549, MG63 and SMMC-7721 cell lines in an in vitro bioassay. Full article
Open AccessCommunication Six New Tetraprenylated Alkaloids from the South China Sea Gorgonian Echinogorgia pseudossapo
Mar. Drugs 2014, 12(2), 672-681; doi:10.3390/md12020672
Received: 25 November 2013 / Revised: 10 December 2013 / Accepted: 13 January 2014 / Published: 27 January 2014
Cited by 8 | PDF Full-text (681 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Six new tetraprenylated alkaloids, designated as malonganenones L–Q (16), were isolated from the gorgonian Echinogorgia pseudossapo, collected in Daya Bay of Guangdong Province, China. The structures of 16 featuring a methyl group at N-3 and a
[...] Read more.
Six new tetraprenylated alkaloids, designated as malonganenones L–Q (16), were isolated from the gorgonian Echinogorgia pseudossapo, collected in Daya Bay of Guangdong Province, China. The structures of 16 featuring a methyl group at N-3 and a tetraprenyl chain at N-7 in the hypoxanthine core were established by extensive spectroscopic analyses. Compounds 16 were tested for their inhibitory activity against the phosphodiesterases (PDEs)-4D, 5A, and 9A, and compounds 1 and 6 exhibited moderate inhibitory activity against PDE4D with IC50 values of 8.5 and 20.3 µM, respectively. Full article
(This article belongs to the collection Bioactive Compounds from Marine Invertebrates)
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Open AccessArticle Polyunsaturated Aldehydes from Large Phytoplankton of the Atlantic Ocean Surface (42°N to 33°S)
Mar. Drugs 2014, 12(2), 682-699; doi:10.3390/md12020682
Received: 19 November 2013 / Revised: 10 January 2014 / Accepted: 15 January 2014 / Published: 27 January 2014
Cited by 6 | PDF Full-text (859 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Polyunsaturated aldehydes (PUAs) are organic compounds mainly produced by diatoms, after cell wounding. These compounds are increasingly reported as teratogenic for species of grazers and deleterious for phytoplanktonic species, but there is still scarce information regarding concentration ranges and the composition of PUAs
[...] Read more.
Polyunsaturated aldehydes (PUAs) are organic compounds mainly produced by diatoms, after cell wounding. These compounds are increasingly reported as teratogenic for species of grazers and deleterious for phytoplanktonic species, but there is still scarce information regarding concentration ranges and the composition of PUAs in the open ocean. In this study, we analyzed the spatial distribution and the type of aldehydes produced by the large-sized (>10 μm) phytoplankton in the Atlantic Ocean surface. Analyses were conducted on PUAs released after mechanical disruption of the phytoplankton cells, referred to here as potential PUAs (pPUAs). Results show the ubiquitous presence of pPUA in the open ocean, including upwelling areas, as well as oligotrophic gyres. Total pPUA concentrations ranged from zero to 4.18 pmol from cells in 1 L. Identified PUAs were heptadienal, octadienal and decadienal, with heptadienal being the most common (79% of total stations). PUA amount and composition across the Atlantic Ocean was mainly related to the nitrogen:phosphorus ratio, suggesting nutrient-driven mechanisms of PUA production. Extending the range of trophic conditions considered by adding data reported for productive coastal waters, we found a pattern of PUA variation in relation to trophic status. Full article
(This article belongs to the Special Issue Metabolites in Diatoms)
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Open AccessArticle Spongionella Secondary Metabolites Protect Mitochondrial Function in Cortical Neurons against Oxidative Stress
Mar. Drugs 2014, 12(2), 700-718; doi:10.3390/md12020700
Received: 21 November 2013 / Revised: 7 January 2014 / Accepted: 8 January 2014 / Published: 27 January 2014
Cited by 9 | PDF Full-text (1323 KB) | HTML Full-text | XML Full-text
Abstract
The marine habitat provides a large number of structurally-diverse bioactive compounds for drug development. Marine sponges have been studied over many years and are found to be a rich source of these bioactive chemicals. This study is focused on the evaluation of the
[...] Read more.
The marine habitat provides a large number of structurally-diverse bioactive compounds for drug development. Marine sponges have been studied over many years and are found to be a rich source of these bioactive chemicals. This study is focused on the evaluation of the activity of six diterpene derivatives isolated from Spongionella sp. on mitochondrial function using an oxidative in vitro stress model. The test compounds include the Gracilins (A, H, K, J and L) and tetrahydroaplysulphurin-1. Compounds were co-incubated with hydrogen peroxide for 12 hours to determine their protective capacities and their effect on markers of apoptosis and Nrf2/ARE pathways was evaluated. Results conclude that Gracilins preserve neurons against oxidative damage, and that in particular, tetrahydroaplysulphurin-1 shows a complete neuroprotective activity. Oxidative stress is linked to mitochondrial dysfunction and consequently to neurodegenerative disorders like Parkinson and Alzheimer diseases, Friedreich ataxia or Amyotrophic lateral sclerosis. This neuroprotection against oxidation conditions suggest that these metabolites could be interesting lead candidates in drug development for neurodegenerative diseases. Full article
(This article belongs to the collection Bioactive Compounds from Marine Invertebrates)
Open AccessArticle Continuous Drug Release by Sea Anemone Nematostella vectensis Stinging Microcapsules
Mar. Drugs 2014, 12(2), 734-745; doi:10.3390/md12020734
Received: 26 November 2013 / Revised: 8 January 2014 / Accepted: 8 January 2014 / Published: 27 January 2014
Cited by 1 | PDF Full-text (813 KB) | HTML Full-text | XML Full-text
Abstract
Transdermal delivery is an attractive option for drug delivery. Nevertheless, the skin is a tough barrier and only a limited number of drugs can be delivered through it. The most difficult to deliver are hydrophilic drugs. The stinging mechanism of the cnidarians is
[...] Read more.
Transdermal delivery is an attractive option for drug delivery. Nevertheless, the skin is a tough barrier and only a limited number of drugs can be delivered through it. The most difficult to deliver are hydrophilic drugs. The stinging mechanism of the cnidarians is a sophisticated injection system consisting of microcapsular nematocysts, which utilize built-in high osmotic pressures to inject a submicron tubule that penetrates and delivers their contents to the prey. Here we show, for the first time, that the nematocysts of the starlet sea anemone Nematostella vectensis can be isolated and incorporated into a topical formulation for continuous drug delivery. We demonstrate quantitative delivery of nicotinamide and lidocaine hydrochloride as a function of microcapsular dose or drug exposure. We also show how the released submicron tubules can be exploited as a skin penetration enhancer prior to and independently of drug application. The microcapsules are non-irritant and may offer an attractive alternative for hydrophilic transdermal drug delivery. Full article
(This article belongs to the Special Issue Mechanism of Action Analysis for Marine Compounds)
Open AccessArticle Prenylated Indolediketopiperazine Peroxides and Related Homologues from the Marine Sediment-Derived Fungus Penicillium brefeldianum SD-273
Mar. Drugs 2014, 12(2), 746-756; doi:10.3390/md12020746
Received: 21 November 2013 / Revised: 10 January 2014 / Accepted: 15 January 2014 / Published: 27 January 2014
Cited by 6 | PDF Full-text (694 KB) | HTML Full-text | XML Full-text
Abstract
Three new indolediketopiperazine peroxides, namely, 24-hydroxyverruculogen (1), 26-hydroxyverruculogen (2), and 13-O-prenyl-26-hydroxyverruculogen (3), along with four known homologues (47), were isolated and identified from the culture extract of the marine sediment-derived fungus
[...] Read more.
Three new indolediketopiperazine peroxides, namely, 24-hydroxyverruculogen (1), 26-hydroxyverruculogen (2), and 13-O-prenyl-26-hydroxyverruculogen (3), along with four known homologues (47), were isolated and identified from the culture extract of the marine sediment-derived fungus Penicillium brefeldianum SD-273. Their structures were determined based on the extensive spectroscopic analysis and compound 1 was confirmed by X-ray crystallographic analysis. The absolute configuration of compounds 13 was determined using chiral HPLC analysis of their acidic hydrolysates. Each of the isolated compounds was evaluated for antibacterial and cytotoxic activity as well as brine shrimp (Artemia salina) lethality. Full article
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Open AccessArticle A Chemoinformatics Approach to the Discovery of Lead-Like Molecules from Marine and Microbial Sources En Route to Antitumor and Antibiotic Drugs
Mar. Drugs 2014, 12(2), 757-778; doi:10.3390/md12020757
Received: 21 November 2013 / Revised: 16 December 2013 / Accepted: 16 January 2014 / Published: 27 January 2014
Cited by 7 | PDF Full-text (2099 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
The comprehensive information of small molecules and their biological activities in the PubChem database allows chemoinformatic researchers to access and make use of large-scale biological activity data to improve the precision of drug profiling. A Quantitative Structure–Activity Relationship approach, for classification, was used
[...] Read more.
The comprehensive information of small molecules and their biological activities in the PubChem database allows chemoinformatic researchers to access and make use of large-scale biological activity data to improve the precision of drug profiling. A Quantitative Structure–Activity Relationship approach, for classification, was used for the prediction of active/inactive compounds relatively to overall biological activity, antitumor and antibiotic activities using a data set of 1804 compounds from PubChem. Using the best classification models for antibiotic and antitumor activities a data set of marine and microbial natural products from the AntiMarin database were screened—57 and 16 new lead compounds for antibiotic and antitumor drug design were proposed, respectively. All compounds proposed by our approach are classified as non-antibiotic and non-antitumor compounds in the AntiMarin database. Recently several of the lead-like compounds proposed by us were reported as being active in the literature. Full article
(This article belongs to the Special Issue Metabolomics - Applications in Marine Natural Products Chemistry)
Open AccessArticle Another Facet to the Anticancer Response to Lamellarin D: Induction of Cellular Senescence through Inhibition of Topoisomerase I and Intracellular Ros Production
Mar. Drugs 2014, 12(2), 779-798; doi:10.3390/md12020779
Received: 27 November 2013 / Revised: 13 December 2013 / Accepted: 7 January 2014 / Published: 27 January 2014
Cited by 7 | PDF Full-text (1247 KB) | HTML Full-text | XML Full-text
Abstract
Lamellarin D (LamD) is a marine alkaloid with broad spectrum antitumor activities. Multiple intracellular targets of LamD, which affect cancer cell growth and induce apoptosis, have been identified. These include nuclear topoisomerase I, relevant kinases (such as cyclin-dependent kinase 2) and the mitochondrial
[...] Read more.
Lamellarin D (LamD) is a marine alkaloid with broad spectrum antitumor activities. Multiple intracellular targets of LamD, which affect cancer cell growth and induce apoptosis, have been identified. These include nuclear topoisomerase I, relevant kinases (such as cyclin-dependent kinase 2) and the mitochondrial electron transport chain. While we have previously demonstrated that LamD at micromolar range deploys strong cytotoxicity by inducing mitochondrial apoptosis, mechanisms of its cytostatic effect have not yet been characterized. Here, we demonstrated that induction of cellular senescence (depicted by cell cycle arrest in G2 associated with β-galactosidase activity) is a common response to subtoxic concentrations of LamD. Cellular senescence is observed in a large panel of cancer cells following in vitro or in vivo exposure to LamD. The onset of cellular senescence is dependent on the presence of intact topoisomerase I since topoisomerase I-mutated cells are resistant to senescence induced by LamD. LamD-induced senescence occurs without important loss of telomere integrity. Instead, incubation with LamD results in the production of intracellular reactive oxygen species (ROS), which are critical for senescence as demonstrated by the inhibitory effect of antioxidants. In addition, cancer cells lacking mitochondrial DNA also exhibit cellular senescence upon LamD exposure indicating that LamD can trigger senescence, unlike apoptosis, in the absence of functional mitochondria. Overall, our results identify senescence-associated growth arrest as a powerful effect of LamD and add compelling evidence for the pharmacological interest of lamellarins as potential anticancer agents. Full article
(This article belongs to the Special Issue Mechanism of Action Analysis for Marine Compounds)
Open AccessArticle Isolation and Characterization of Anti-Adenoviral Secondary Metabolites from Marine Actinobacteria
Mar. Drugs 2014, 12(2), 799-821; doi:10.3390/md12020799
Received: 17 December 2013 / Revised: 10 January 2014 / Accepted: 15 January 2014 / Published: 28 January 2014
Cited by 3 | PDF Full-text (1429 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Adenovirus infections in immunocompromised patients are associated with high mortality rates. Currently, there are no effective anti-adenoviral therapies available. It is well known that actinobacteria can produce secondary metabolites that are attractive in drug discovery due to their structural diversity and their evolved
[...] Read more.
Adenovirus infections in immunocompromised patients are associated with high mortality rates. Currently, there are no effective anti-adenoviral therapies available. It is well known that actinobacteria can produce secondary metabolites that are attractive in drug discovery due to their structural diversity and their evolved interaction with biomolecules. Here, we have established an extract library derived from actinobacteria isolated from Vestfjorden, Norway, and performed a screening campaign to discover anti-adenoviral compounds. One extract with anti-adenoviral activity was found to contain a diastereomeric 1:1 mixture of the butenolide secondary alcohols 1a and 1b. By further cultivation and analysis, we could isolate 1a and 1b in different diastereomeric ratio. In addition, three more anti-adenoviral butenolides 2, 3 and 4 with differences in their side-chains were isolated. In this study, the anti-adenoviral activity of these compounds was characterized and substantial differences in the cytotoxic potential between the butenolide analogs were observed. The most potent butenolide analog 3 displayed an EC50 value of 91 μM and no prominent cytotoxicity at 2 mM. Furthermore, we propose a biosynthetic pathway for these compounds based on their relative time of appearance and structure. Full article
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Open AccessArticle Antibacterial and Antibiofilm Activities of Tryptoquivalines and Meroditerpenes Isolated from the Marine-Derived Fungi Neosartorya paulistensis, N. laciniosa, N. tsunodae, and the Soil Fungi N. fischeri and N. siamensis
Mar. Drugs 2014, 12(2), 822-839; doi:10.3390/md12020822
Received: 25 December 2013 / Revised: 17 January 2014 / Accepted: 20 January 2014 / Published: 28 January 2014
Cited by 21 | PDF Full-text (987 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
A new meroditerpene, sartorypyrone C (5), was isolated, together with the known tryptoquivalines L (1a), H (1b), F (1c), 3′-(4-oxoquinazolin-3-yl) spiro [1H-indole-3,5′]-2,2′-dione (2) and 4(3H)-quinazolinone (3), from
[...] Read more.
A new meroditerpene, sartorypyrone C (5), was isolated, together with the known tryptoquivalines L (1a), H (1b), F (1c), 3′-(4-oxoquinazolin-3-yl) spiro [1H-indole-3,5′]-2,2′-dione (2) and 4(3H)-quinazolinone (3), from the culture of the marine sponge-associated fungus Neosartorya paulistensis (KUFC 7897), while reexamination of the fractions remaining from a previous study of the culture of the diseased coral-derived fungus N. laciniosa (KUFC 7896) led to isolation of a new tryptoquivaline derivative tryptoquivaline T (1d). Compounds 1ad, 2, 3, and 5, together with aszonapyrones A (4a) and B (4b), chevalones B (6) and C (7a), sartorypyrones B (7b) and A (8), were tested for their antibacterial activity against four reference strains (Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa), as well as the environmental multidrug-resistant isolates. Only aszonapyrone A (4a) and sartorypyrone A (8) exhibited significant antibacterial activity as well as synergism with antibiotics against the Gram-positive multidrug-resistant strains. Antibiofilm assays of aszonapyrone A (4a) and sartorypyrone A (8) showed that practically no biofilm was formed in the presence of their 2× MIC and MIC. However, the presence of a sub-inhibitory concentration of ½ MIC of 4a and 8 was found to increase the biofilm production in both reference strain and the multidrug-resistant isolates of S. aureus. Full article
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Open AccessArticle Bioactive Cembranoids, Sarcocrassocolides P–R, from the Dongsha Atoll Soft Coral Sarcophyton crassocaule
Mar. Drugs 2014, 12(2), 840-850; doi:10.3390/md12020840
Received: 12 November 2013 / Revised: 13 December 2013 / Accepted: 17 January 2014 / Published: 28 January 2014
Cited by 3 | PDF Full-text (921 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
New cembranoids, sarcocrassocolides P–R (13) and four known compounds (47) were isolated from the soft coral Sarcophyton crassocaule. The structures of the metabolites were determined by extensive spectroscopic analysis. Compounds 35 and
[...] Read more.
New cembranoids, sarcocrassocolides P–R (13) and four known compounds (47) were isolated from the soft coral Sarcophyton crassocaule. The structures of the metabolites were determined by extensive spectroscopic analysis. Compounds 35 and 7 were shown to exhibit cytotoxicity toward a limited panel of cancer cell lines and all compounds 17 displayed potent in vitro anti-inflammatory activity in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells by inhibiting the expression of inducible nitric oxide synthase (iNOS) protein. Compound 7 also showed significant activity in reducing the accumulation of cyclooxygenase-2 (COX-2) protein in the same macrophage cells. Full article
(This article belongs to the collection Bioactive Compounds from Marine Invertebrates)
Open AccessArticle Gageostatins A–C, Antimicrobial Linear Lipopeptides from a Marine Bacillus subtilis
Mar. Drugs 2014, 12(2), 871-885; doi:10.3390/md12020871
Received: 29 November 2013 / Revised: 19 December 2013 / Accepted: 20 January 2014 / Published: 31 January 2014
Cited by 6 | PDF Full-text (403 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Concerning the requirements of effective drug candidates to combat against high rising multidrug resistant pathogens, we isolated three new linear lipopeptides, gageostatins A–C (13), consisting of hepta-peptides and new 3-β-hydroxy fatty acids from the fermentation broth of a marine-derived
[...] Read more.
Concerning the requirements of effective drug candidates to combat against high rising multidrug resistant pathogens, we isolated three new linear lipopeptides, gageostatins A–C (13), consisting of hepta-peptides and new 3-β-hydroxy fatty acids from the fermentation broth of a marine-derived bacterium Bacillus subtilis. Their structures were elucidated by analyzing a combination of extensive 1D, 2D NMR spectroscopic data and high resolution ESIMS data. Fatty acids, namely 3-β-hydroxy-11-methyltridecanoic and 3-β-hydroxy-9,11-dimethyltridecanoic acids were characterized in lipopeptides 1 and 2, respectively, whereas an unsaturated fatty acid (E)-7,9-dimethylundec-2-enoic acid was assigned in 3. The 3R configuration of the stereocenter of 3-β-hydroxy fatty acids in 1 and 2 was established by Mosher’s MTPA method. The absolute stereochemistry of amino acid residues in 13 was ascertained by acid hydrolysis followed by Marfey’s derivatization studies. Gageostatins 13 exhibited good antifungal activities with MICs values of 4–32 µg/mL when tested against pathogenic fungi (R. solani, B. cinerea and C. acutatum) and moderate antibacterial activity against bacteria (B. subtilis, S. aeureus, S. typhi and P. aeruginosa) with MICs values of 8–64 µg/mL. Futhermore, gageostatins 13 displayed cytotoxicity against six human cancer cell lines with GI50 values of 4.6–19.6 µg/mL. It is also noteworthy that mixed compounds 1+2 displayed better antifungal and cytotoxic activities than individuals. Full article
Open AccessArticle Fucoidan Extracted from Fucus evanescens Prevents Endotoxin-Induced Damage in a Mouse Model of Endotoxemia
Mar. Drugs 2014, 12(2), 886-898; doi:10.3390/md12020886
Received: 7 November 2013 / Revised: 24 January 2014 / Accepted: 26 January 2014 / Published: 31 January 2014
Cited by 8 | PDF Full-text (1645 KB) | HTML Full-text | XML Full-text
Abstract
An important problem of treating patients with endotoxemia is to find drugs to reduce the negative effects of endotoxin on the organism. We tested fucoidan (sulfated polysaccharide) from the brown alga Fucus evanescens as a potential drug in a mouse model of endotoxemia
[...] Read more.
An important problem of treating patients with endotoxemia is to find drugs to reduce the negative effects of endotoxin on the organism. We tested fucoidan (sulfated polysaccharide) from the brown alga Fucus evanescens as a potential drug in a mouse model of endotoxemia inducted by lipopolysaccharide (LPS). The survival time of mice injected with LPS increased under fucoidan treatment compared with the group of mice injected with LPS only. The preventive administration of fucoidan to mice with endotoxemia resulted in inhibition of increased levels of proinflammatory cytokines (TNFα and IL-6), as well as decreasing of the processes of hypercoagulability. The parenteral or per os administration of fucoidan resulted in decreasing the degree of microcirculatory disorders and secondary dystrophic-destructive changes in parenchymal organs of mice with endotoxemia. Taken together, these results demonstrate that fucoidan prevents endotoxin-induced damage in a mouse model of endotoxemia and increases the mice’s resistance to LPS. Full article
(This article belongs to the Special Issue Marine Compounds and Inflammation)
Open AccessArticle Bioprospecting from Marine Sediments of New Brunswick, Canada: Exploring the Relationship between Total Bacterial Diversity and Actinobacteria Diversity
Mar. Drugs 2014, 12(2), 899-925; doi:10.3390/md12020899
Received: 13 November 2013 / Revised: 7 January 2014 / Accepted: 21 January 2014 / Published: 13 February 2014
Cited by 9 | PDF Full-text (1019 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Actinomycetes are an important resource for the discovery of natural products with therapeutic properties. Bioprospecting for actinomycetes typically proceeds without a priori knowledge of the bacterial diversity present in sampled habitats. In this study, we endeavored to determine if overall bacterial diversity in
[...] Read more.
Actinomycetes are an important resource for the discovery of natural products with therapeutic properties. Bioprospecting for actinomycetes typically proceeds without a priori knowledge of the bacterial diversity present in sampled habitats. In this study, we endeavored to determine if overall bacterial diversity in marine sediments, as determined by 16S rDNA amplicon pyrosequencing, could be correlated with culturable actinomycete diversity, and thus serve as a powerful tool in guiding future bioprospecting efforts. Overall bacterial diversity was investigated in eight marine sediments from four sites in New Brunswick, Canada, resulting in over 44,000 high quality sequences ( = 5610 per sample). Analysis revealed all sites exhibited significant diversity (H = 5.4 to 6.7). Furthermore, statistical analysis of species level bacterial communities (D = 0.03) indicated community composition varied according to site and was strongly influenced by sediment physiochemical composition. In contrast, cultured actinomycetes (n = 466, 98.3% Streptomyces) were ubiquitously distributed among all sites and distribution was not influenced by sediment composition, suggesting that the biogeography of culturable actinomycetes does not correlate with overall bacterial diversity in the samples examined. These actinomycetes provide a resource for future secondary metabolite discovery, as exemplified by the antimicrobial activity observed from preliminary investigation. Full article
Open AccessArticle Synthesis of PPAR-γ Activators Inspired by the Marine Natural Product, Paecilocin A
Mar. Drugs 2014, 12(2), 926-939; doi:10.3390/md12020926
Received: 24 December 2013 / Revised: 10 January 2014 / Accepted: 22 January 2014 / Published: 13 February 2014
Cited by 3 | PDF Full-text (927 KB) | HTML Full-text | XML Full-text
Abstract
A series of N-substituted phthalimide derivatives were synthesized based on a pharmacophore study of paecilocin A (a natural PPAR-γ agonist) and synthetic leads. The introduction of hydrophilic and hydrophobic groups to the phthalimide skeleton yielded compounds 314. Compound 7
[...] Read more.
A series of N-substituted phthalimide derivatives were synthesized based on a pharmacophore study of paecilocin A (a natural PPAR-γ agonist) and synthetic leads. The introduction of hydrophilic and hydrophobic groups to the phthalimide skeleton yielded compounds 314. Compound 7 showed significant PPAR-γ activation in a luciferase assay using rat liver Ac2F cells. Docking simulations showed that a free hydroxyl group on the phthalimide head and a suitable hydrophilic tail, including a phenyl linker, were beneficial for PPAR-γ activation. Compound 7 and rosiglitazone concentration-dependently activated PPAR-γ with EC50 values of 0.67 μM and 0.028 μM, respectively. These phthalimide derivatives could be further investigated as a new class of PPAR-γ ligands. Full article
Open AccessArticle Antimicrobial Activity of the Marine Alkaloids, Clathrodin and Oroidin, and Their Synthetic Analogues
Mar. Drugs 2014, 12(2), 940-963; doi:10.3390/md12020940
Received: 25 November 2013 / Revised: 17 January 2014 / Accepted: 23 January 2014 / Published: 14 February 2014
Cited by 13 | PDF Full-text (939 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Marine organisms produce secondary metabolites that may be valuable for the development of novel drug leads as such and can also provide structural scaffolds for the design and synthesis of novel bioactive compounds. The marine alkaloids, clathrodin and oroidin, which were originally isolated
[...] Read more.
Marine organisms produce secondary metabolites that may be valuable for the development of novel drug leads as such and can also provide structural scaffolds for the design and synthesis of novel bioactive compounds. The marine alkaloids, clathrodin and oroidin, which were originally isolated from sponges of the genus, Agelas, were prepared and evaluated for their antimicrobial activity against three bacterial strains (Enterococcus faecalis, Staphylococcus aureus and Escherichia coli) and one fungal strain (Candida albicans), and oroidin was found to possess promising Gram-positive antibacterial activity. Using oroidin as a scaffold, 34 new analogues were designed, prepared and screened for their antimicrobial properties. Of these compounds, 12 exhibited >80% inhibition of the growth of at least one microorganism at a concentration of 50 µM. The most active derivative was found to be 4-phenyl-2-aminoimidazole 6h, which exhibited MIC90 (minimum inhibitory concentration) values of 12.5 µM against the Gram-positive bacteria and 50 µM against E. coli. The selectivity index between S. aureus and mammalian cells, which is important to consider in the evaluation of a compound’s potential as an antimicrobial lead, was found to be 2.9 for compound 6h. Full article
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Open AccessArticle Dietary Fucoxanthin Increases Metabolic Rate and Upregulated mRNA Expressions of the PGC-1alpha Network, Mitochondrial Biogenesis and Fusion Genes in White Adipose Tissues of Mice
Mar. Drugs 2014, 12(2), 964-982; doi:10.3390/md12020964
Received: 17 December 2013 / Revised: 22 January 2014 / Accepted: 23 January 2014 / Published: 14 February 2014
Cited by 7 | PDF Full-text (1460 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
The mechanism for how fucoxanthin (FX) suppressed adipose accumulation is unclear. We aim to investigate the effects of FX on metabolic rate and expressions of genes related to thermogenesis, mitochondria biogenesis and homeostasis. Using a 2 × 2 factorial design, four groups of
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The mechanism for how fucoxanthin (FX) suppressed adipose accumulation is unclear. We aim to investigate the effects of FX on metabolic rate and expressions of genes related to thermogenesis, mitochondria biogenesis and homeostasis. Using a 2 × 2 factorial design, four groups of mice were respectively fed a high sucrose (50% sucrose) or a high-fat diet (23% butter + 7% soybean oil) supplemented with or without 0.2% FX. FX significantly increased oxygen consumption and carbon dioxide production and reduced white adipose tissue (WAT) mass. The mRNA expressions of peroxisome proliferator-activated receptor (PPAR) γ coactivator-1α (PGC-1α), cell death-inducing DFFA-like effecter a (CIDEA), PPARα, PPARγ, estrogen-related receptor α (ERRα), β3-adrenergic receptor (β3-AR) and deiodinase 2 (Dio2) were significantly upregulated in inguinal WAT (iWAT) and epididymal WAT (eWAT) by FX. Mitochondrial biogenic genes, nuclear respiratory factor 1 (NRF1) and NRF2, were increased in eWAT by FX. Noticeably, FX upregulated genes of mitochondrial fusion, mitofusin 1 (Mfn1), Mfn2 and optic atrophy 1 (OPA1), but not mitochondrial fission, Fission 1, in both iWAT and eWAT. In conclusion, dietary FX enhanced the metabolic rate and lowered adipose mass irrespective of the diet. These were associated with upregulated genes of the PGC-1α network and mitochondrial fusion in eWAT and iWAT. Full article
(This article belongs to the Special Issue Marine Carotenoids (Special Issue))
Open AccessArticle Transcriptional Changes Caused by Bisphenol A in Oryzias javanicus, a Fish Species Highly Adaptable to Environmental Salinity
Mar. Drugs 2014, 12(2), 983-998; doi:10.3390/md12020983
Received: 10 December 2013 / Revised: 6 January 2014 / Accepted: 6 February 2014 / Published: 14 February 2014
Cited by 2 | PDF Full-text (725 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
The Javanese medaka, Oryzias javanicus, is a fish highly adaptable to various environmental salinities. Here, we investigated the effects of the environmental pollutant bisphenol A (BPA; an endocrine disrupting chemical) on gene expression levels in this species acclimated to different salinities. Using
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The Javanese medaka, Oryzias javanicus, is a fish highly adaptable to various environmental salinities. Here, we investigated the effects of the environmental pollutant bisphenol A (BPA; an endocrine disrupting chemical) on gene expression levels in this species acclimated to different salinities. Using cDNA microarrays, we detected the induction of differential expression of genes by BPA, and compared the transcriptional changes caused by chemical exposure at different salinities. There were marked transcriptional changes induced by BPA between treatments. While 533 genes were induced by a factor of more than two when O. javanicus was exposed to BPA in seawater, only 215 genes were induced in freshwater. Among those genes, only 78 were shared and changed significantly their expression in both seawater and freshwater. Those genes were mainly involved in cellular processes and signaling pathway. We then categorized by functional group genes specifically induced by BPA exposure in seawater or freshwater. Gene expression changes were further confirmed in O. javanicus exposed to various concentrations of BPA, using quantitative real-time reverse transcription PCR based on primer sets for 28 selected genes. Full article
(This article belongs to the Special Issue Marine Fish Endocrine Disruption)
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Open AccessArticle Butremycin, the 3-Hydroxyl Derivative of Ikarugamycin and a Protonated Aromatic Tautomer of 5′-Methylthioinosine from a Ghanaian Micromonospora sp. K310
Mar. Drugs 2014, 12(2), 999-1012; doi:10.3390/md12020999
Received: 22 November 2013 / Revised: 24 December 2013 / Accepted: 21 January 2014 / Published: 14 February 2014
Cited by 10 | PDF Full-text (436 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
A new actinomycete strain Micromonospora sp. K310 was isolated from Ghanaian mangrove river sediment. Spectroscopy-guided fractionation led to the isolation of two new compounds from the fermentation culture. One of the compounds is butremycin (2) which is the (3-hydroxyl) derivative of
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A new actinomycete strain Micromonospora sp. K310 was isolated from Ghanaian mangrove river sediment. Spectroscopy-guided fractionation led to the isolation of two new compounds from the fermentation culture. One of the compounds is butremycin (2) which is the (3-hydroxyl) derivative of the known Streptomyces metabolite ikarugamycin (1) and the other compound is a protonated aromatic tautomer of 5′-methylthioinosine (MTI) (3). Both new compounds were characterized by 1D, 2D NMR and MS data. Butremycin (2) displayed weak antibacterial activity against Gram-positive S. aureus ATCC 25923, the Gram-negative E. coli ATCC 25922 and a panel of clinical isolates of methicillin-resistant S. aureus (MRSA) strains while 3 did not show any antibacterial activity against these microbes. Full article
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Open AccessArticle Solwaric Acids A and B, Antibacterial Aromatic Acids from a Marine Solwaraspora sp.
Mar. Drugs 2014, 12(2), 1013-1022; doi:10.3390/md12021013
Received: 19 December 2013 / Revised: 24 January 2014 / Accepted: 24 January 2014 / Published: 14 February 2014
Cited by 10 | PDF Full-text (563 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Two novel trialkyl-substituted aromatic acids, solwaric acids A and B, were isolated from a marine Solwaraspora sp. cultivated from the ascidian Trididemnum orbiculatum. Solwaric acids A and B were isotopically labeled with U-13C glucose, and analysis of a 13C–
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Two novel trialkyl-substituted aromatic acids, solwaric acids A and B, were isolated from a marine Solwaraspora sp. cultivated from the ascidian Trididemnum orbiculatum. Solwaric acids A and B were isotopically labeled with U-13C glucose, and analysis of a 13C–13C COSY allowed for unambiguous determination of the location of the phenyl methyl group. The two novel compounds demonstrated antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive Staphylococcus aureus (MSSA). Full article
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Open AccessArticle Mode of Action of Diterpene and Characterization of Related Metabolites from the Soft Coral, Xenia elongata
Mar. Drugs 2014, 12(2), 1102-1115; doi:10.3390/md12021102
Received: 9 December 2013 / Revised: 25 January 2014 / Accepted: 27 January 2014 / Published: 20 February 2014
Cited by 5 | PDF Full-text (1100 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Chemical and biological investigation of the cultured marine soft coral Xenia elongata led to the isolation of two new diterpenes (2, 3). Their structures were elucidated using a combination of NMR and mass spectrometry. Biological evaluations and assessments were determined
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Chemical and biological investigation of the cultured marine soft coral Xenia elongata led to the isolation of two new diterpenes (2, 3). Their structures were elucidated using a combination of NMR and mass spectrometry. Biological evaluations and assessments were determined using the specific apoptosis induction assay based on genetically engineered mammalian cell line D3 deficient in Bak and Bax and derived from a mouse epithelial cell. The diterpenes induce apoptosis in low micromolar concentrations. The results indicate that the previously isolated compound (1) affects cell in a manner similar to that of HSP90 and HDAC inhibitors and in a manner opposite of PI3 kinase/mTOR inhibitors. Compound (3) inhibits selectively HDAC6 in high micromolar concentrations. Full article
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Open AccessArticle Tanjungides A and B: New Antitumoral Bromoindole Derived Compounds from Diazona cf formosa. Isolation and Total Synthesis
Mar. Drugs 2014, 12(2), 1116-1130; doi:10.3390/md12021116
Received: 2 December 2013 / Revised: 16 December 2013 / Accepted: 24 January 2014 / Published: 21 February 2014
Cited by 5 | PDF Full-text (961 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Tanjungides A (1) (Z isomer) and B (2) (E isomer), two novel dibrominated indole enamides, have been isolated from the tunicate Diazona cf formosa. Their structures were determined by spectroscopic methods including HRMS, and extensive 1D
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Tanjungides A (1) (Z isomer) and B (2) (E isomer), two novel dibrominated indole enamides, have been isolated from the tunicate Diazona cf formosa. Their structures were determined by spectroscopic methods including HRMS, and extensive 1D and 2D NMR. The stereochemistry of the cyclised cystine present in both compounds was determined by Marfey’s analysis after chemical degradation and hydrolysis. We also report the first total synthesis of these compounds using methyl 1H-indole-3-carboxylate as starting material and a linear sequence of 11 chemical steps. Tanjungides A and B exhibit significant cytotoxicity against human tumor cell lines. Full article
Open AccessArticle The Marine Sponge-Derived Inorganic Polymers, Biosilica and Polyphosphate, as Morphogenetically Active Matrices/Scaffolds for the Differentiation of Human Multipotent Stromal Cells: Potential Application in 3D Printing and Distraction Osteogenesis
Mar. Drugs 2014, 12(2), 1131-1147; doi:10.3390/md12021131
Received: 28 November 2013 / Revised: 10 January 2014 / Accepted: 17 February 2014 / Published: 21 February 2014
Cited by 19 | PDF Full-text (1300 KB) | HTML Full-text | XML Full-text
Abstract
The two marine inorganic polymers, biosilica (BS), enzymatically synthesized from ortho-silicate, and polyphosphate (polyP), a likewise enzymatically synthesized polymer consisting of 10 to >100 phosphate residues linked by high-energy phosphoanhydride bonds, have previously been shown to display a morphogenetic effect on osteoblasts. In
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The two marine inorganic polymers, biosilica (BS), enzymatically synthesized from ortho-silicate, and polyphosphate (polyP), a likewise enzymatically synthesized polymer consisting of 10 to >100 phosphate residues linked by high-energy phosphoanhydride bonds, have previously been shown to display a morphogenetic effect on osteoblasts. In the present study, the effect of these polymers on the differential differentiation of human multipotent stromal cells (hMSC), mesenchymal stem cells, that had been encapsulated into beads of the biocompatible plant polymer alginate, was studied. The differentiation of the hMSCs in the alginate beads was directed either to the osteogenic cell lineage by exposure to an osteogenic medium (mineralization activation cocktail; differentiation into osteoblasts) or to the chondrogenic cell lineage by incubating in chondrocyte differentiation medium (triggering chondrocyte maturation). Both biosilica and polyP, applied as Ca2+ salts, were found to induce an increased mineralization in osteogenic cells; these inorganic polymers display also morphogenetic potential. The effects were substantiated by gene expression studies, which revealed that biosilica and polyP strongly and significantly increase the expression of bone morphogenetic protein 2 (BMP-2) and alkaline phosphatase (ALP) in osteogenic cells, which was significantly more pronounced in osteogenic versus chondrogenic cells. A differential effect of the two polymers was seen on the expression of the two collagen types, I and II. While collagen Type I is highly expressed in osteogenic cells, but not in chondrogenic cells after exposure to biosilica or polyP, the upregulation of the steady-state level of collagen Type II transcripts in chondrogenic cells is comparably stronger than in osteogenic cells. It is concluded that the two polymers, biosilica and polyP, are morphogenetically active additives for the otherwise biologically inert alginate polymer. It is proposed that alginate, supplemented with polyP and/or biosilica, is a suitable biomaterial that promotes the growth and differentiation of hMSCs and might be beneficial for application in 3D tissue printing of hMSCs and for the delivery of hMSCs in fractures, surgically created during distraction osteogenesis. Full article
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Open AccessArticle Krempfielins N–P, New Anti-Inflammatory Eunicellins from a Taiwanese Soft Coral Cladiella krempfi
Mar. Drugs 2014, 12(2), 1148-1156; doi:10.3390/md12021148
Received: 11 December 2013 / Revised: 22 January 2014 / Accepted: 7 February 2014 / Published: 21 February 2014
Cited by 10 | PDF Full-text (869 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Three new eunicellin-type diterpenoids, krempfielins N–P (13), were isolated from a Taiwanese soft coral Cladiella krempfi. The structures of the new metabolites were elucidated by extensive spectroscopic analysis and by comparison with spectroscopic data of related known compounds.
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Three new eunicellin-type diterpenoids, krempfielins N–P (13), were isolated from a Taiwanese soft coral Cladiella krempfi. The structures of the new metabolites were elucidated by extensive spectroscopic analysis and by comparison with spectroscopic data of related known compounds. Compound 3 exhibited activity to inhibit superoxide anion generation. Both 1 and 3, in particular 1, were shown to display significant anti-inflammatory activity by inhibiting the elastase release in FMLP/CB-induced human neutrophils. Full article

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Open AccessReview Targeting Nuclear Receptors with Marine Natural Products
Mar. Drugs 2014, 12(2), 601-635; doi:10.3390/md12020601
Received: 12 November 2013 / Revised: 20 December 2013 / Accepted: 7 January 2014 / Published: 27 January 2014
Cited by 5 | PDF Full-text (1934 KB) | HTML Full-text | XML Full-text
Abstract
Nuclear receptors (NRs) are important pharmaceutical targets because they are key regulators of many metabolic and inflammatory diseases, including diabetes, dyslipidemia, cirrhosis, and fibrosis. As ligands play a pivotal role in modulating nuclear receptor activity, the discovery of novel ligands for nuclear receptors
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Nuclear receptors (NRs) are important pharmaceutical targets because they are key regulators of many metabolic and inflammatory diseases, including diabetes, dyslipidemia, cirrhosis, and fibrosis. As ligands play a pivotal role in modulating nuclear receptor activity, the discovery of novel ligands for nuclear receptors represents an interesting and promising therapeutic approach. The search for novel NR agonists and antagonists with enhanced selectivities prompted the exploration of the extraordinary chemical diversity associated with natural products. Recent studies involving nuclear receptors have disclosed a number of natural products as nuclear receptor ligands, serving to re-emphasize the translational possibilities of natural products in drug discovery. In this review, the natural ligands of nuclear receptors will be described with an emphasis on their mechanisms of action and their therapeutic potentials, as well as on strategies to determine potential marine natural products as nuclear receptor modulators. Full article
(This article belongs to the Special Issue Mechanism of Action Analysis for Marine Compounds)
Open AccessReview Marine Low Molecular Weight Natural Products as Potential Cancer Preventive Compounds
Mar. Drugs 2014, 12(2), 636-671; doi:10.3390/md12020636
Received: 3 December 2013 / Revised: 14 January 2014 / Accepted: 15 January 2014 / Published: 27 January 2014
Cited by 14 | PDF Full-text (1170 KB) | HTML Full-text | XML Full-text
Abstract
Due to taxonomic positions and special living environments, marine organisms produce secondary metabolites that possess unique structures and biological activities. This review is devoted to recently isolated and/or earlier described marine compounds with potential or established cancer preventive activities, their biological sources, molecular
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Due to taxonomic positions and special living environments, marine organisms produce secondary metabolites that possess unique structures and biological activities. This review is devoted to recently isolated and/or earlier described marine compounds with potential or established cancer preventive activities, their biological sources, molecular mechanisms of their action, and their associations with human health and nutrition. The review covers literature published in 2003–2013 years and focuses on findings of the last 2 years. Full article
(This article belongs to the collection Marine Compounds and Cancer)
Open AccessReview Trabectedin and Plitidepsin: Drugs from the Sea that Strike the Tumor Microenvironment
Mar. Drugs 2014, 12(2), 719-733; doi:10.3390/md12020719
Received: 29 November 2013 / Revised: 13 January 2014 / Accepted: 14 January 2014 / Published: 27 January 2014
Cited by 13 | PDF Full-text (649 KB) | HTML Full-text | XML Full-text
Abstract
The prevailing paradigm states that cancer cells acquire multiple genetic mutations in oncogenes or tumor suppressor genes whose respective activation/up-regulation or loss of function serve to impart aberrant properties, such as hyperproliferation or inhibition of cell death. However, a tumor is now considered
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The prevailing paradigm states that cancer cells acquire multiple genetic mutations in oncogenes or tumor suppressor genes whose respective activation/up-regulation or loss of function serve to impart aberrant properties, such as hyperproliferation or inhibition of cell death. However, a tumor is now considered as an organ-like structure, a complex system composed of multiple cell types (e.g., tumor cells, inflammatory cells, endothelial cells, fibroblasts, etc.) all embedded in an inflammatory stroma. All these components influence each other in a complex and dynamic cross-talk, leading to tumor cell survival and progression. As the microenvironment has such a crucial role in tumor pathophysiology, it represents an attractive target for cancer therapy. In this review, we describe the mechanism of action of trabectedin and plitidepsin as an example of how these specific drugs of marine origin elicit their antitumor activity not only by targeting tumor cells but also the tumor microenvironment. Full article
(This article belongs to the collection Marine Compounds and Cancer)
Open AccessReview Fucoidan as a Marine Anticancer Agent in Preclinical Development
Mar. Drugs 2014, 12(2), 851-870; doi:10.3390/md12020851
Received: 15 November 2013 / Revised: 31 December 2013 / Accepted: 10 January 2014 / Published: 28 January 2014
Cited by 39 | PDF Full-text (765 KB) | HTML Full-text | XML Full-text
Abstract
Fucoidan is a fucose-containing sulfated polysaccharide derived from brown seaweeds, crude extracts of which are commercially available as nutritional supplements. Recent studies have demonstrated antiproliferative, antiangiogenic, and anticancer properties of fucoidan in vitro. Accordingly, the anticancer effects of fucoidan have been shown
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Fucoidan is a fucose-containing sulfated polysaccharide derived from brown seaweeds, crude extracts of which are commercially available as nutritional supplements. Recent studies have demonstrated antiproliferative, antiangiogenic, and anticancer properties of fucoidan in vitro. Accordingly, the anticancer effects of fucoidan have been shown to vary depending on its structure, while it can target multiple receptors or signaling molecules in various cell types, including tumor cells and immune cells. Low toxicity and the in vitro effects of fucoidan mentioned above make it a suitable agent for cancer prevention or treatment. However, preclinical development of natural marine products requires in vivo examination of purified compounds in animal tumor models. This review discusses the effects of systemic and local administration of fucoidan on tumor growth, angiogenesis, and immune reaction and whether in vivo and in vitro results are likely applicable to the development of fucoidan as a marine anticancer drug. Full article
(This article belongs to the collection Marine Compounds and Cancer)
Open AccessReview The Lipopolysaccharide Export Pathway in Escherichia coli: Structure, Organization and Regulated Assembly of the Lpt Machinery
Mar. Drugs 2014, 12(2), 1023-1042; doi:10.3390/md12021023
Received: 15 January 2014 / Revised: 22 January 2014 / Accepted: 28 January 2014 / Published: 17 February 2014
Cited by 12 | PDF Full-text (862 KB) | HTML Full-text | XML Full-text
Abstract
The bacterial outer membrane (OM) is a peculiar biological structure with a unique composition that contributes significantly to the fitness of Gram-negative bacteria in hostile environments. OM components are all synthesized in the cytosol and must, then, be transported efficiently across three compartments
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The bacterial outer membrane (OM) is a peculiar biological structure with a unique composition that contributes significantly to the fitness of Gram-negative bacteria in hostile environments. OM components are all synthesized in the cytosol and must, then, be transported efficiently across three compartments to the cell surface. Lipopolysaccharide (LPS) is a unique glycolipid that paves the outer leaflet of the OM. Transport of this complex molecule poses several problems to the cells due to its amphipatic nature. In this review, the multiprotein machinery devoted to LPS transport to the OM is discussed together with the challenges associated with this process and the solutions that cells have evolved to address the problem of LPS biogenesis. Full article
(This article belongs to the Special Issue Marine Lipopolysaccharides)
Open AccessReview Co-Cultivation—A Powerful Emerging Tool for Enhancing the Chemical Diversity of Microorganisms
Mar. Drugs 2014, 12(2), 1043-1065; doi:10.3390/md12021043
Received: 9 January 2014 / Revised: 23 January 2014 / Accepted: 6 February 2014 / Published: 17 February 2014
Cited by 38 | PDF Full-text (779 KB) | HTML Full-text | XML Full-text
Abstract
Marine-derived bacteria and fungi are promising sources of novel bioactive compounds that are important for drug discovery programs. However, as encountered in terrestrial microorganisms there is a high rate of redundancy that results in the frequent re-discovery of known compounds. Apparently only a
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Marine-derived bacteria and fungi are promising sources of novel bioactive compounds that are important for drug discovery programs. However, as encountered in terrestrial microorganisms there is a high rate of redundancy that results in the frequent re-discovery of known compounds. Apparently only a part of the biosynthetic genes that are harbored by fungi and bacteria are transcribed under routine laboratory conditions which involve cultivation of axenic microbial strains. Many biosynthetic genes remain silent and are not expressed in vitro thereby seriously limiting the chemical diversity of microbial compounds that can be obtained through fermentation. In contrast to this, co-cultivation (also called mixed fermentation) of two or more different microorganisms tries to mimic the ecological situation where microorganisms always co-exist within complex microbial communities. The competition or antagonism experienced during co-cultivation is shown to lead to a significantly enhanced production of constitutively present compounds and/or to an accumulation of cryptic compounds that are not detected in axenic cultures of the producing strain. This review highlights the power of co-cultivation for increasing the chemical diversity of bacteria and fungi drawing on published studies from the marine and from the terrestrial habitat alike. Full article
Open AccessReview Marketed Marine Natural Products in the Pharmaceutical and Cosmeceutical Industries: Tips for Success
Mar. Drugs 2014, 12(2), 1066-1101; doi:10.3390/md12021066
Received: 2 December 2013 / Revised: 14 January 2014 / Accepted: 27 January 2014 / Published: 17 February 2014
Cited by 67 | PDF Full-text (723 KB) | HTML Full-text | XML Full-text
Abstract
The marine environment harbors a number of macro and micro organisms that have developed unique metabolic abilities to ensure their survival in diverse and hostile habitats, resulting in the biosynthesis of an array of secondary metabolites with specific activities. Several of these metabolites
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The marine environment harbors a number of macro and micro organisms that have developed unique metabolic abilities to ensure their survival in diverse and hostile habitats, resulting in the biosynthesis of an array of secondary metabolites with specific activities. Several of these metabolites are high-value commercial products for the pharmaceutical and cosmeceutical industries. The aim of this review is to outline the paths of marine natural products discovery and development, with a special focus on the compounds that successfully reached the market and particularly looking at the approaches tackled by the pharmaceutical and cosmetic companies that succeeded in marketing those products. The main challenges faced during marine bioactives discovery and development programs were analyzed and grouped in three categories: biodiversity (accessibility to marine resources and efficient screening), supply and technical (sustainable production of the bioactives and knowledge of the mechanism of action) and market (processes, costs, partnerships and marketing). Tips to surpass these challenges are given in order to improve the market entry success rates of highly promising marine bioactives in the current pipelines, highlighting what can be learned from the successful and unsuccessful stories that can be applied to novel and/or ongoing marine natural products discovery and development programs. Full article

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