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Mar. Drugs, Volume 13, Issue 5 (May 2015), Pages 2559-3258

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Open AccessArticle Anti-Inflammatory and Analgesic Effects of the Marine-Derived Compound Excavatolide B Isolated from the Culture-Type Formosan Gorgonian Briareum excavatum
Mar. Drugs 2015, 13(5), 2559-2579; doi:10.3390/md13052559
Received: 18 March 2015 / Revised: 17 April 2015 / Accepted: 20 April 2015 / Published: 27 April 2015
Cited by 10 | PDF Full-text (1266 KB) | HTML Full-text | XML Full-text
Abstract
In recent years, several marine-derived compounds have been clinically evaluated. Diterpenes are secondary metabolites from soft coral that exhibit anti-inflammatory, anti-tumor and cytotoxic activities. In the present study, we isolated a natural diterpene product, excavatolide B, from cultured Formosan gorgonian Briareum excavatum and
[...] Read more.
In recent years, several marine-derived compounds have been clinically evaluated. Diterpenes are secondary metabolites from soft coral that exhibit anti-inflammatory, anti-tumor and cytotoxic activities. In the present study, we isolated a natural diterpene product, excavatolide B, from cultured Formosan gorgonian Briareum excavatum and investigated its anti-inflammatory activities. We found that excavatolide B significantly inhibited the mRNA expression of the proinflammatory mediators, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), in lipopolysaccharide (LPS)-challenged murine macrophages (RAW 264.7). We also examined the anti-inflammatory and anti-nociceptive effects of excavatolide B on intraplantar carrageenan-induced inflammatory responses. Excavatolide B was found to significantly attenuate carrageenan-induced nociceptive behaviors, mechanical allodynia, thermal hyperalgesia, weight bearing deficits and paw edema. In addition, excavatolide B inhibited iNOS, as well as the infiltration of immune cells in carrageenan-induced inflammatory paw tissue. Full article
(This article belongs to the Special Issue Marine Secondary Metabolites)
Open AccessArticle Influence of Amino Acid Compositions and Peptide Profiles on Antioxidant Capacities of Two Protein Hydrolysates from Skipjack Tuna (Katsuwonus pelamis) Dark Muscle
Mar. Drugs 2015, 13(5), 2580-2601; doi:10.3390/md13052580
Received: 7 March 2015 / Revised: 9 April 2015 / Accepted: 21 April 2015 / Published: 27 April 2015
Cited by 15 | PDF Full-text (595 KB) | HTML Full-text | XML Full-text
Abstract
Influence of amino acid compositions and peptide profiles on antioxidant capacities of two protein hydrolysates from skipjack tuna (Katsuwonus pelamis) dark muscle was investigated. Dark muscles from skipjack tuna were hydrolyzed using five separate proteases, including pepsin, trypsin, Neutrase, papain and
[...] Read more.
Influence of amino acid compositions and peptide profiles on antioxidant capacities of two protein hydrolysates from skipjack tuna (Katsuwonus pelamis) dark muscle was investigated. Dark muscles from skipjack tuna were hydrolyzed using five separate proteases, including pepsin, trypsin, Neutrase, papain and Alcalase. Two hydrolysates, ATH and NTH, prepared using Alcalase and Neutrase, respectively, showed the strongest antioxidant capacities and were further fractionated using ultrafiltration and gel filtration chromatography. Two fractions, Fr.A3 and Fr.B2, isolated from ATH and NTH, respectively, showed strong radical scavenging activities toward 2,2-diphenyl-1-picrylhydrazyl radicals (EC50 1.08% ± 0.08% and 0.98% ± 0.07%), hydroxyl radicals (EC50 0.22% ± 0.03% and 0.48% ± 0.05%), and superoxide anion radicals (EC50 1.31% ± 0.11% and 1.56% ± 1.03%) and effectively inhibited lipid peroxidation. Eighteen peptides from Fr.A3 and 13 peptides from Fr.B2 were isolated by reversed-phase high performance liquid chromatography, and their amino acid sequences were determined. The elevated antioxidant activity of Fr.A3 might be due to its high content of hydrophobic and aromatic amino acid residues (181.1 and 469.9 residues/1000 residues, respectively), small molecular sizes (3–6 peptides), low molecular weights (524.78 kDa), and amino acid sequences (antioxidant score 6.11). This study confirmed that a smaller molecular size, the presence of hydrophobic and aromatic amino acid residues, and the amino acid sequences were the key factors that determined the antioxidant activities of the proteins, hydrolysates and peptides. The results also demonstrated that the derived hydrolysates and fractions from skipjack tuna (K. pelamis) dark muscles could prevent oxidative reactions and might be useful for food preservation and medicinal purposes. Full article
(This article belongs to the Special Issue Marine Functional Food)
Open AccessArticle Functional Diversity of Anti-Lipopolysaccharide Factor Isoforms in Shrimp and Their Characters Related to Antiviral Activity
Mar. Drugs 2015, 13(5), 2602-2616; doi:10.3390/md13052602
Received: 31 March 2015 / Revised: 17 April 2015 / Accepted: 20 April 2015 / Published: 27 April 2015
Cited by 15 | PDF Full-text (945 KB) | HTML Full-text | XML Full-text
Abstract
Anti-lipopolysaccharide factor (ALF) is a small protein with broad-spectrum antimicrobial activity, which has potential application in the disease control. Previously, we isolated seven ALF isoforms from the Chinese shrimp Fenneropenaeus chinensis. In the present study, their distributions in tissues of shrimp were
[...] Read more.
Anti-lipopolysaccharide factor (ALF) is a small protein with broad-spectrum antimicrobial activity, which has potential application in the disease control. Previously, we isolated seven ALF isoforms from the Chinese shrimp Fenneropenaeus chinensis. In the present study, their distributions in tissues of shrimp were analyzed and the data showed that different isoforms had different expression profiles, which suggested that they might have different functions. Then, the functions of different isoforms were studied by analyzing the antibacterial and antiviral activities of the functional domain of ALFs, the LPS-binding domain (LBD), which were synthesized by chemical methods. Different ALFs showed distinct antibacterial and antiviral activities, which were consistent with their diverse tissue distribution patterns. Sequence analysis on the LBD domain of different isoforms revealed that an identical lysine residue site was specifically conserved in peptides with anti-WSSV activity. In order to confirm whether this lysine residue is critical to the antiviral activity of the peptide, new peptides were synthesized by changing residues at this site. Changing the lysine residue at the specific site to other amino acid residue, the antiviral activity of the peptide apparently decreased. While replacing other residue with a lysine residue at this site in LBD peptide without anti-WSSV activity, the peptide will obtain the antiviral activity to WSSV. These results not only showed us a comprehensive understanding on the function of ALFs from F. chinensis, but also provided clues for the development of ALFs as potential therapeutic drugs to WSSV. Full article
(This article belongs to the Special Issue Marine Peptides and Their Mimetics)
Open AccessArticle Novel Adociaquinone Derivatives from the Indonesian Sponge Xestospongia sp.
Mar. Drugs 2015, 13(5), 2617-2628; doi:10.3390/md13052617
Received: 3 March 2015 / Revised: 2 April 2015 / Accepted: 3 April 2015 / Published: 28 April 2015
Cited by 2 | PDF Full-text (798 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Seven new adociaquinone derivatives, xestoadociaquinones A (1a), B (1b), 14-carboxy-xestoquinol sulfate (2) and xestoadociaminals A–D (3a, 3c, 4a, 4c), together with seven known compounds (511) were isolated from
[...] Read more.
Seven new adociaquinone derivatives, xestoadociaquinones A (1a), B (1b), 14-carboxy-xestoquinol sulfate (2) and xestoadociaminals A–D (3a, 3c, 4a, 4c), together with seven known compounds (511) were isolated from an Indonesian marine sponge Xestospongia sp. Their structures were elucidated by extensive 1D and 2D NMR and mass spectrometric data. All the compounds were evaluated for their potential inhibitory activity against eight different protein kinases involved in cell proliferation, cancer, diabetes and neurodegenerative disorders as well as for their antioxidant and antibacterial activities. Full article
(This article belongs to the Special Issue Marine Compounds as Protein Kinase Inhibitors)
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Open AccessArticle The Cytoprotective Effect of Petalonia binghamiae Methanol Extract against Oxidative Stress in C2C12 Myoblasts: Mediation by Upregulation of Heme Oxygenase-1 and Nuclear Factor-Erythroid 2 Related Factor 2
Mar. Drugs 2015, 13(5), 2666-2679; doi:10.3390/md13052666
Received: 13 March 2015 / Revised: 8 April 2015 / Accepted: 21 April 2015 / Published: 29 April 2015
Cited by 3 | PDF Full-text (837 KB) | HTML Full-text | XML Full-text
Abstract
This study was designed to examine the protective effects of the marine brown algae Petalonia binghamiae against oxidative stress-induced cellular damage and to elucidate the underlying mechanisms. P. binghamiae methanol extract (PBME) prevented hydrogen peroxide (H2O2)-induced growth inhibition and
[...] Read more.
This study was designed to examine the protective effects of the marine brown algae Petalonia binghamiae against oxidative stress-induced cellular damage and to elucidate the underlying mechanisms. P. binghamiae methanol extract (PBME) prevented hydrogen peroxide (H2O2)-induced growth inhibition and exhibited scavenging activity against intracellular reactive oxygen species (ROS) induced by H2O2 in mouse-derived C2C12 myoblasts. PBME also significantly attenuated H2O2-induced comet tail formation in a comet assay, histone γH2A.X phosphorylation, and annexin V-positive cells, suggesting that PBME prevented H2O2-induced cellular DNA damage and apoptotic cell death. Furthermore, PBME increased the levels of heme oxygenase-1 (HO-1), a potent antioxidant enzyme, associated with the induction of nuclear factor-erythroid 2 related factor 2 (Nrf2). However, zinc protoporphyrin IX, a HO-1 competitive inhibitor, significantly abolished the protective effects of PBME on H2O2-induced ROS generation, growth inhibition, and apoptosis. Collectively, these results demonstrate that PBME augments the antioxidant defense capacity through activation of the Nrf2/HO-1 pathway. Full article
(This article belongs to the Special Issue Marine Functional Food)
Open AccessArticle Employment of Marine Polysaccharides to Manufacture Functional Biocomposites for Aquaculture Feeding Applications
Mar. Drugs 2015, 13(5), 2680-2693; doi:10.3390/md13052680
Received: 3 March 2015 / Revised: 17 April 2015 / Accepted: 17 April 2015 / Published: 29 April 2015
Cited by 1 | PDF Full-text (539 KB) | HTML Full-text | XML Full-text
Abstract
In this study, polysaccharides of marine origin (agar, alginate and κ-carrageenan) were used to embed nutrients to fabricate biocomposites to be employed in animal feeding. The consistency of biocomposites in water has been evaluated up to 14 days, by several methods: swelling, nutrient
[...] Read more.
In this study, polysaccharides of marine origin (agar, alginate and κ-carrageenan) were used to embed nutrients to fabricate biocomposites to be employed in animal feeding. The consistency of biocomposites in water has been evaluated up to 14 days, by several methods: swelling, nutrient release and granulometric analysis. Biocomposites were produced with varying percentages of nutrients (5%–25%) and polysaccharides (1%–2%–3%). All possible biopolymer combinations were tested in order to select those with the best network strength. The best performing biocomposites were those manufactured with agar 2% and nutrients 10%, showing the lowest percentage of water absorption and nutrient release. Biocomposites made of agar 2% and nutrients 10% were the most stable in water and were therefore used to analyze their behavior in water with respect to the release of quercetin, a phenolic compound with demonstrated high antibacterial and antioxidant activities. The leaching of such molecules in water was therefore employed as a further indicator of biocomposite water stability. Altogether, our results confirm the suitability of agar as a binder for biocomposites and provide a positive contribution to aquaculture. Full article
(This article belongs to the collection Marine Polysaccharides)
Open AccessArticle Dereplication and Chemotaxonomical Studies of Marine Algae of the Ochrophyta and Rhodophyta Phyla
Mar. Drugs 2015, 13(5), 2714-2731; doi:10.3390/md13052714
Received: 6 March 2015 / Revised: 9 April 2015 / Accepted: 21 April 2015 / Published: 30 April 2015
Cited by 3 | PDF Full-text (523 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Dereplication and chemotaxonomic studies of six marine algae of the Ochrophyta and one of the Rhodophyta phyla resulted in the detection of 22 separate compounds. All 16 secondary metabolites, including four new compounds (1619), could be rapidly dereplicated using
[...] Read more.
Dereplication and chemotaxonomic studies of six marine algae of the Ochrophyta and one of the Rhodophyta phyla resulted in the detection of 22 separate compounds. All 16 secondary metabolites, including four new compounds (1619), could be rapidly dereplicated using HPLC-NMR and HPLC-MS methodologies in conjunction with the MarinLit database. This study highlights the advantages of using NMR data (acquired via HPLC-NMR) for database searching and for the overall dereplication of natural products. Full article
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Open AccessArticle Anti-Obese Effect of Glucosamine and Chitosan Oligosaccharide in High-Fat Diet-Induced Obese Rats
Mar. Drugs 2015, 13(5), 2732-2756; doi:10.3390/md13052732
Received: 11 March 2015 / Revised: 7 April 2015 / Accepted: 22 April 2015 / Published: 30 April 2015
Cited by 18 | PDF Full-text (2543 KB) | HTML Full-text | XML Full-text
Abstract
Objective: This study is to evaluate the anti-obese effects of glucosamine (GLC) and chitosan oligosaccharide (COS) on high-fat diet-induced obese rats. Methods: The rats were randomly divided into twelve groups: a normal diet group (NF), a high-fat diet group (HF), Orlistat group, GLC
[...] Read more.
Objective: This study is to evaluate the anti-obese effects of glucosamine (GLC) and chitosan oligosaccharide (COS) on high-fat diet-induced obese rats. Methods: The rats were randomly divided into twelve groups: a normal diet group (NF), a high-fat diet group (HF), Orlistat group, GLC high-, middle-, and low-dose groups (GLC-H, GLC-M, GLC-L), COS1 (COS, number-average molecular weight ≤1000) high-, middle-, and low-dose groups (COS1-H, COS1-M, COS1-L), and COS2 (COS, number-average molecular weight ≤3000) high-, middle-, and low-dose groups (COS2-H, COS2-M, COS2-L). All groups received oral treatment by gavage once daily for a period of six weeks. Results: Rats fed with COS1 gained the least weight among all the groups (P < 0.01), and these rats lost more weight than those treated with Orlistat. In addition to the COS2-H and Orlistat groups, the serum total cholesterol (CHO) and low-density lipoprotein cholesterol (LDL-C) levels were significantly reduced in all treatment groups compared to the HF group (P < 0.01). The various doses of GLC, COS1 and COS2 reduced the expression levels of PPARγ and LXRα mRNA in the white adipose tissue. Conclusions: The results above demonstrated that GLC, COS1, and COS2 improved dyslipidemia and prevented body weight gains by inhibiting the adipocyte differentiation in obese rats induced by a high-fat diet. Thus, these agents may potentially be used to treat obesity. Full article
Open AccessArticle Eunicellin-Based Diterpenoids, Hirsutalins S–V, from the Formosan Soft Coral Cladiella hirsuta
Mar. Drugs 2015, 13(5), 2757-2769; doi:10.3390/md13052757
Received: 24 March 2015 / Revised: 20 April 2015 / Accepted: 20 April 2015 / Published: 30 April 2015
Cited by 8 | PDF Full-text (555 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Four new eunicellin-type hirsutalins S–V (14), along with a known compound (–)-6α-hydroxy polyanthellin A (5), were isolated from the soft coral Cladiella hirsuta. The structures of the metabolites were determined by extensive spectroscopic analysis. Cytotoxity of
[...] Read more.
Four new eunicellin-type hirsutalins S–V (14), along with a known compound (–)-6α-hydroxy polyanthellin A (5), were isolated from the soft coral Cladiella hirsuta. The structures of the metabolites were determined by extensive spectroscopic analysis. Cytotoxity of compounds 15 against the proliferation of a limited panel of cancer cell lines was measured. Anti-inflammatory activity of compounds 15 was evaluated by measuring their ability in suppressing superoxide anion generation and elastase release in fMLP/ CB-induced human neutrophils. Full article
Open AccessArticle Natural Marine and Synthetic Xenobiotics Get on Nematode’s Nerves: Neuro-Stimulating and Neurotoxic Findings in Caenorhabditis elegans
Mar. Drugs 2015, 13(5), 2785-2812; doi:10.3390/md13052785
Received: 9 February 2015 / Revised: 15 April 2015 / Accepted: 23 April 2015 / Published: 6 May 2015
Cited by 3 | PDF Full-text (1256 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Marine algae release a plethora of organic halogenated compounds, many of them with unknown ecological impact if environmentally realistic concentrations are applied. One major compound is dibromoacetic acid (DBAA) which was tested for neurotoxicity in the invertebrate model organism Caenorhabditis elegans (C.
[...] Read more.
Marine algae release a plethora of organic halogenated compounds, many of them with unknown ecological impact if environmentally realistic concentrations are applied. One major compound is dibromoacetic acid (DBAA) which was tested for neurotoxicity in the invertebrate model organism Caenorhabditis elegans (C. elegans). This natural compound was compared with the widespread synthetic xenobiotic tetrabromobisphenol-A (TBBP-A) found in marine sediments and mussels. We found a neuro-stimulating effect for DBAA; this is contradictory to existing toxicological reports of mammals that applied comparatively high dosages. For TBBP-A, we found a hormetic concentration-effect relationship. As chemicals rarely occur isolated in the environment, a combination of both organobromines was also examined. Surprisingly, the presence of DBAA increased the toxicity of TBBP-A. Our results demonstrated that organohalogens have the potential to affect single organisms especially by altering the neurological processes, even with promoting effects on exposed organisms. Full article
Open AccessArticle Tilapia Piscidin 4 (TP4) Stimulates Cell Proliferation and Wound Closure in MRSA-Infected Wounds in Mice
Mar. Drugs 2015, 13(5), 2813-2833; doi:10.3390/md13052813
Received: 9 March 2015 / Revised: 16 April 2015 / Accepted: 21 April 2015 / Published: 6 May 2015
Cited by 3 | PDF Full-text (1277 KB) | HTML Full-text | XML Full-text
Abstract
Antimicrobial peptides (AMPs) are endogenous antibiotics that directly affect microorganisms, and also have a variety of receptor-mediated functions. One such AMP, Tilapia piscidin 4 (TP4), was isolated from Nile tilapia (Oreochromis niloticus); TP4 has antibacterial effects and regulates the innate immune
[...] Read more.
Antimicrobial peptides (AMPs) are endogenous antibiotics that directly affect microorganisms, and also have a variety of receptor-mediated functions. One such AMP, Tilapia piscidin 4 (TP4), was isolated from Nile tilapia (Oreochromis niloticus); TP4 has antibacterial effects and regulates the innate immune system. The aim of the present study was to characterize the role of TP4 in the regulation of wound closure in mice and proliferation of a keratinocyte cell line (HaCaT) and fibroblast cell line (Hs-68). In vitro, TP4 stimulated cell proliferation and activated collagen I, collagen III, and keratinocyte growth factor (KGF) gene expression in Hs-68 cells, which induces keratin production by HaCaT cells. This effect was detectable at TP4 concentrations of 6.25 µg/mL in both cell lines. In vivo, TP4 was found to be highly effective at combating peritonitis and wound infection caused by MRSA in mouse models, without inducing adverse behavioral effects or liver or kidney toxicity. Taken together, our results indicate that TP4 enhances the survival rate of mice infected with the bacterial pathogen MRSA through both antimicrobial and wound closure activities mediated by epidermal growth factor (EGF), transforming growth factor (TGF), and vascular endothelial growth factor (VEGF). The peptide is likely involved in antibacterial processes and regulation of tissue homeostasis in infected wounds in mice. Overall, these results suggest that TP4 may be suitable for development as a novel topical agent for wound dressing. Full article
Open AccessArticle The Effect of Dissolved Polyunsaturated Aldehydes on Microzooplankton Growth Rates in the Chesapeake Bay and Atlantic Coastal Waters
Mar. Drugs 2015, 13(5), 2834-2856; doi:10.3390/md13052834
Received: 25 January 2015 / Revised: 22 April 2015 / Accepted: 27 April 2015 / Published: 6 May 2015
Cited by 3 | PDF Full-text (813 KB) | HTML Full-text | XML Full-text
Abstract
Allelopathy is wide spread among marine phytoplankton, including diatoms, which can produce cytotoxic secondary metabolites such as polyunsaturated aldehydes (PUA). Most studies on diatom-produced PUA have been dedicated to their inhibitory effects on reproduction and development of marine invertebrates. However, little information exists
[...] Read more.
Allelopathy is wide spread among marine phytoplankton, including diatoms, which can produce cytotoxic secondary metabolites such as polyunsaturated aldehydes (PUA). Most studies on diatom-produced PUA have been dedicated to their inhibitory effects on reproduction and development of marine invertebrates. However, little information exists on their impact on key herbivores in the ocean, microzooplankton. This study examined the effects of dissolved 2E,4E-octadienal and 2E,4E-heptadienal on the growth rates of natural ciliate and dinoflagellate populations in the Chesapeake Bay and the coastal Atlantic waters. The overall effect of PUA on microzooplankton growth was negative, especially at the higher concentrations, but there were pronounced differences in response among common planktonic species. For example, the growth of Codonella sp., Leegaardiella sol, Prorodon sp., and Gyrodinium spirale was impaired at 2 nM, whereas Strombidium conicum, Cyclotrichium gigas, and Gymnodinium sp. were not affected even at 20 nM. These results indicate that PUA can induce changes in microzooplankton dynamics and species composition. Full article
(This article belongs to the Special Issue Metabolites in Diatoms)
Open AccessArticle Astaxanthin from Haematococcus pluvialis Prevents Oxidative Stress on Human Endothelial Cells without Toxicity
Mar. Drugs 2015, 13(5), 2857-2874; doi:10.3390/md13052857
Received: 27 January 2015 / Revised: 7 April 2015 / Accepted: 27 April 2015 / Published: 7 May 2015
Cited by 14 | PDF Full-text (1070 KB) | HTML Full-text | XML Full-text
Abstract
Astaxanthin, a powerful antioxidant, is a good candidate for the prevention of intracellular oxidative stress. The aim of the study was to compare the antioxidant activity of astaxanthin present in two natural extracts from Haematococcus pluvialis, a microalgae strain, with that of
[...] Read more.
Astaxanthin, a powerful antioxidant, is a good candidate for the prevention of intracellular oxidative stress. The aim of the study was to compare the antioxidant activity of astaxanthin present in two natural extracts from Haematococcus pluvialis, a microalgae strain, with that of synthetic astaxanthin. Natural extracts were obtained either by solvent or supercritical extraction methods. UV, HPLC-DAD and (HPLC-(atmospheric pressure chemical ionization (APCI)+)/ion trap-MS) characterizations of both natural extracts showed similar compositions of carotenoids, but different percentages in free astaxanthin and its ester derivatives. The Trolox equivalent antioxidant capacity (TEAC) assay showed that natural extracts containing esters displayed stronger antioxidant activities than free astaxanthin. Their antioxidant capacities to inhibit intracellular oxidative stress were then evaluated on HUVEC cells. The intracellular antioxidant activity in natural extracts was approximately 90-times higher than synthetic astaxanthin (5 µM). No modification, neither in the morphology nor in the viability, of vascular human cells was observed by in vitro biocompatibility study up to 10 µM astaxanthin concentrations. Therefore, these results revealed the therapeutic potential of the natural extracts in vascular human cell protection against oxidative stress without toxicity, which could be exploited in prevention and/or treatment of cardiovascular diseases. Full article
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Open AccessArticle λ-Carrageenan Suppresses Tomato Chlorotic Dwarf Viroid (TCDVd) Replication and Symptom Expression in Tomatoes
Mar. Drugs 2015, 13(5), 2875-2889; doi:10.3390/md13052875
Received: 27 February 2015 / Revised: 18 April 2015 / Accepted: 27 April 2015 / Published: 8 May 2015
Cited by 1 | PDF Full-text (1278 KB) | HTML Full-text | XML Full-text
Abstract
The effect of carrageenans on tomato chlorotic dwarf viroid (TCDVd) replication and symptom expression was studied. Three-week-old tomato plants were spray-treated with iota(ɩ)-, lambda(λ)-, and kappa(κ)-carrageenan at 1 g·L−1 and inoculated with TCDVd after 48 h. The λ-carrageenan significantly suppressed viroid symptom
[...] Read more.
The effect of carrageenans on tomato chlorotic dwarf viroid (TCDVd) replication and symptom expression was studied. Three-week-old tomato plants were spray-treated with iota(ɩ)-, lambda(λ)-, and kappa(κ)-carrageenan at 1 g·L−1 and inoculated with TCDVd after 48 h. The λ-carrageenan significantly suppressed viroid symptom expression after eight weeks of inoculation, only 28% plants showed distinctive bunchy-top symptoms as compared to the 82% in the control group. Viroid concentration was reduced in the infected shoot cuttings incubated in λ-carrageenan amended growth medium. Proteome analysis revealed that 16 tomato proteins were differentially expressed in the λ-carrageenan treated plants. Jasmonic acid related genes, allene oxide synthase (AOS) and lipoxygenase (LOX), were up-regulated in λ-carrageenan treatment during viroid infection. Taken together, our results suggest that λ-carrageenan induced tomato defense against TCDVd, which was partly jasmonic acid (JA) dependent, and that it could be explored in plant protection against viroid infection. Full article
(This article belongs to the collection Marine Polysaccharides)
Open AccessArticle Alginate Hydrogels Coated with Chitosan for Wound Dressing
Mar. Drugs 2015, 13(5), 2890-2908; doi:10.3390/md13052890
Received: 24 February 2015 / Revised: 2 April 2015 / Accepted: 29 April 2015 / Published: 11 May 2015
Cited by 15 | PDF Full-text (2607 KB) | HTML Full-text | XML Full-text
Abstract
In this work, a coating of chitosan onto alginate hydrogels was realized using the water-soluble hydrochloride form of chitosan (CH-Cl), with the dual purpose of imparting antibacterial activity and delaying the release of hydrophilic molecules from the alginate matrix. Alginate hydrogels with different
[...] Read more.
In this work, a coating of chitosan onto alginate hydrogels was realized using the water-soluble hydrochloride form of chitosan (CH-Cl), with the dual purpose of imparting antibacterial activity and delaying the release of hydrophilic molecules from the alginate matrix. Alginate hydrogels with different calcium contents were prepared by the internal setting method and coated by immersion in a CH-Cl solution. Structural analysis by cryo-scanning electron microscopy was carried out to highlight morphological alterations due to the coating layer. Tests in vitro with human mesenchymal stromal cells (MSC) were assessed to check the absence of toxicity of CH-Cl. Swelling, stability in physiological solution and release characteristics using rhodamine B as the hydrophilic model drug were compared to those of relative uncoated hydrogels. Finally, antibacterial activity against Escherichia coli was tested. Results show that alginate hydrogels coated with chitosan hydrochloride described here can be proposed as a novel medicated dressing by associating intrinsic antimicrobial activity with improved sustained release characteristics. Full article
(This article belongs to the collection Marine Polysaccharides)
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Open AccessArticle A New Member of the TBC1D15 Family from Chiloscyllium plagiosum: Rab GTPase-Activating Protein Based on Rab7 as a Substrate
Mar. Drugs 2015, 13(5), 2955-2966; doi:10.3390/md13052955
Received: 11 January 2015 / Revised: 28 April 2015 / Accepted: 5 May 2015 / Published: 13 May 2015
Cited by 1 | PDF Full-text (1448 KB) | HTML Full-text | XML Full-text
Abstract
APSL (active peptide from shark liver) is a hepatic stimulator cytokine from the liver of Chiloscyllium. It can effectively protect islet cells and improve complications in mice with alloxan-induced diabetes. Here, we demonstrate that the APSL sequence is present in the N
[...] Read more.
APSL (active peptide from shark liver) is a hepatic stimulator cytokine from the liver of Chiloscyllium. It can effectively protect islet cells and improve complications in mice with alloxan-induced diabetes. Here, we demonstrate that the APSL sequence is present in the N-terminus of novel TBC (Tre-2, Bub2 and Cdc16) domain family, member 15 (TBC1D15) from Chiloscyllium plagiosum. This shark TBC1D15 gene, which contains an ORF of 2088 bp, was identified from a cDNA library of regenerating shark liver. Bioinformatic analysis showed that the gene is highly homologous to TBC1D15 genes from other species. Moreover, the N-terminus of shark TBC1D15 contains a motif of unknown function (DUF3548), which encompasses the APSL fragment. Rab-GAP activity analysis showed that shark TBC1D15 is a new member of the TBC1D15 family. These results demonstrated that shark TBC1D15 possesses Rab-GAP activity using Rab7 as a substrate, which is a common property of the TBC1D15 family. The involvement of APSL at the N-terminus of TBC1D15 also demonstrates that this protein might be involved in insulin signaling and may be associated with the development of type 2 diabetes. The current findings pave the way for further functional and clinical studies of these proteins from marine sources. Full article
Open AccessArticle Antitumor and Antimicrobial Activity of Some Cyclic Tetrapeptides and Tripeptides Derived from Marine Bacteria
Mar. Drugs 2015, 13(5), 3029-3045; doi:10.3390/md13053029
Received: 21 April 2015 / Revised: 22 April 2015 / Accepted: 6 May 2015 / Published: 15 May 2015
Cited by 1 | PDF Full-text (351 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Marine derived cyclo(Gly-l-Ser-l-Pro-l-Glu) was selected as a lead to evaluate antitumor-antibiotic activity. Histidine was chosen to replace the serine residue to form cyclo(Gly-l-His-l-Pro-l-Glu). Cyclic tetrapeptides (CtetPs) were then synthesized using a solution phase method, and subjected to antitumor and antibiotic assays.
[...] Read more.
Marine derived cyclo(Gly-l-Ser-l-Pro-l-Glu) was selected as a lead to evaluate antitumor-antibiotic activity. Histidine was chosen to replace the serine residue to form cyclo(Gly-l-His-l-Pro-l-Glu). Cyclic tetrapeptides (CtetPs) were then synthesized using a solution phase method, and subjected to antitumor and antibiotic assays. The benzyl group protected CtetPs derivatives, showed better activity against antibiotic-resistant Staphylococcus aureus in the range of 60–120 μM. Benzyl group protected CtetPs 3 and 4, exhibited antitumor activity against several cell lines at a concentration of 80–108 μM. However, shortening the size of the ring to the cyclic tripeptide (CtriP) scaffold, cyclo(Gly-l-Ser-l-Pro), cyclo(Ser-l-Pro-l-Glu) and their analogues showed no antibiotic or antitumor activity. This phenomenon can be explained from their backbone structures. Full article
(This article belongs to the Special Issue Marine Peptides and Their Mimetics)
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Open AccessArticle Anti-Restenotic Roles of Dihydroaustrasulfone Alcohol Involved in Inhibiting PDGF-BB-Stimulated Proliferation and Migration of Vascular Smooth Muscle Cells
Mar. Drugs 2015, 13(5), 3046-3060; doi:10.3390/md13053046
Received: 1 February 2015 / Revised: 3 May 2015 / Accepted: 5 May 2015 / Published: 15 May 2015
Cited by 7 | PDF Full-text (6042 KB) | HTML Full-text | XML Full-text
Abstract
Dihydroaustrasulfone alcohol (DA), an active compound firstly isolated from marine corals, has been reported to reveal anti-cancer and anti-inflammation activities. These reported activities of DA raised a possible application in anti-restenosis. Abnormal proliferation and migration of vascular smooth muscle cells (VSMCs) and the
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Dihydroaustrasulfone alcohol (DA), an active compound firstly isolated from marine corals, has been reported to reveal anti-cancer and anti-inflammation activities. These reported activities of DA raised a possible application in anti-restenosis. Abnormal proliferation and migration of vascular smooth muscle cells (VSMCs) and the stimulation of platelet-derived growth factor (PDGF)-BB play major pathological processes involved in the development of restenosis. Experimental results showed that DA markedly reduced balloon injury-induced neointima formation in the rat carotid artery model and significantly inhibited PDGF-BB-stimulated proliferation and migration of VSMCs. Our data further demonstrated that translational and active levels of several critical signaling cascades involved in VSMC proliferation, such as extracellular signal-regulated kinase/ mitogen-activated protein kinases (ERK/MAPK), phosphatidylinositol 3-kinase (PI3K)/AKT, and signal transducer and activator of transcription (STAT), were obviously inhibited. In addition, DA also decreased the activation and expression levels of gelatinases (matrix metalloproteinase (MMP)-2 and MMP-9) involved in cell migration. In conclusion, our findings indicate that DA can reduce balloon injury-neointimal hyperplasia, the effect of which may be modulated through suppression of VSMC proliferation and migration. These results suggest that DA has potential application as an anti-restenotic agent for the prevention of restenosis. Full article
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Open AccessCommunication SAR of Sponge-Inspired Hemibastadin Congeners Inhibiting Blue Mussel PhenolOxidase
Mar. Drugs 2015, 13(5), 3061-3071; doi:10.3390/md13053061
Received: 27 January 2015 / Revised: 19 April 2015 / Accepted: 5 May 2015 / Published: 15 May 2015
Cited by 4 | PDF Full-text (337 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Hemibastadin derivatives, including the synthetically-derived 5,5′-dibromohemibastadin-1 (DBHB), are potent inhibitors of blue mussel phenoloxidase (PO), which is a key enzyme involved in the firm attachment of this invertebrate to substrates and, thus, a promising molecular target for anti-fouling research. For a systematic investigation
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Hemibastadin derivatives, including the synthetically-derived 5,5′-dibromohemibastadin-1 (DBHB), are potent inhibitors of blue mussel phenoloxidase (PO), which is a key enzyme involved in the firm attachment of this invertebrate to substrates and, thus, a promising molecular target for anti-fouling research. For a systematic investigation of the enzyme inhibitory activity of hemibastadin derivatives, we have synthesized nine new congeners, which feature structural variations of the DBHB core structure. These structural modifications include, e.g., different halogen substituents present at the aromatic rings, different amine moieties linked to the (E)-2-(hydroxyimino)-3-(4-hydroxyphenyl)propionic acid, the presence of free vs. substituted aromatic hydroxyl groups and a free vs. methylated oxime group. All compounds were tested for their inhibitory activity towards the target enzyme in vitro, and IC50 values were calculated. Derivatives, which structurally closely resemble sponge-derived hemibastadins, revealed superior enzyme inhibitory properties vs. congeners featuring structural moieties that are absent in the respective natural products. This study suggests that natural selection has yielded structurally-optimized antifouling compounds. Full article
Open AccessArticle Antidiabetic Activity of Differently Regioselective Chitosan Sulfates in Alloxan-Induced Diabetic Rats
Mar. Drugs 2015, 13(5), 3072-3090; doi:10.3390/md13053072
Received: 21 February 2015 / Revised: 8 April 2015 / Accepted: 4 May 2015 / Published: 15 May 2015
Cited by 3 | PDF Full-text (920 KB) | HTML Full-text | XML Full-text
Abstract
The present study investigated and compared the hypoglycemic activity of differently regioselective chitosan sulfates in alloxan-induced diabetic rats. Compared with the normal control rats, significantly higher blood glucose levels were observed in the alloxan-induced diabetic rats. The differently regioselective chitosan sulfates exhibited hypoglycemic
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The present study investigated and compared the hypoglycemic activity of differently regioselective chitosan sulfates in alloxan-induced diabetic rats. Compared with the normal control rats, significantly higher blood glucose levels were observed in the alloxan-induced diabetic rats. The differently regioselective chitosan sulfates exhibited hypoglycemic activities at different doses and intervals, especially 3-O-sulfochitosan (3-S). The major results are as follows. First, 3,6-di-O-sulfochitosan and 3-O-sulfochitosan exhibited more significant hypoglycemic activities than 2-N-3, 6-di-O-sulfochitosan and 6-O-sulfochitosan. Moreover, 3-S-treated rats showed a more significant reduction of blood glucose levels than those treated by 3,6-di-O-sulfochitosan. These results indicated that –OSO3 at the C3-position of chitosan is a key active site. Second, 3-S significantly reduced the blood glucose levels and regulated the glucose tolerance effect in the experimental rats. Third, treatment with 3-S significantly increased the plasma insulin levels in the experimental diabetic rats. A noticeable hypoglycemic activity of 3-S in the alloxan-induced diabetic rats was shown. Clinical trials are required in the future to confirm the utility of 3-S. Full article
(This article belongs to the collection Marine Polysaccharides)
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Open AccessArticle Bioactive Metabolites from Mangrove Endophytic Fungus Aspergillus sp. 16-5B
Mar. Drugs 2015, 13(5), 3091-3102; doi:10.3390/md13053091
Received: 23 March 2015 / Revised: 27 April 2015 / Accepted: 27 April 2015 / Published: 19 May 2015
Cited by 10 | PDF Full-text (791 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Chemical investigation of the endophytic fungus Aspergillus sp. 16-5B cultured on Czapek’s medium led to the isolation of four new metabolites, aspergifuranone (1), isocoumarin derivatives (±) 2 and (±) 3, and (R)-3-demethylpurpurester A (4), together with
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Chemical investigation of the endophytic fungus Aspergillus sp. 16-5B cultured on Czapek’s medium led to the isolation of four new metabolites, aspergifuranone (1), isocoumarin derivatives (±) 2 and (±) 3, and (R)-3-demethylpurpurester A (4), together with the known purpurester B (5) and pestaphthalides A (6). Their structures were determined by analysis of 1D and 2D NMR spectroscopic data. The absolute configuration of Compound 1 was determined by comparison of the experimental and calculated electronic circular dichroism (ECD) spectra, and that of Compound 4 was revealed by comparing its optical rotation data and CD with those of the literature. The structure of Compound 6 was further confirmed by single-crystal X-ray diffraction experiment using CuKα radiation. All isolated compounds were evaluated for their α-glucosidase inhibitory activities, and Compound 1 showed significant inhibitory activity with IC50 value of 9.05 ± 0.60 μM. Kinetic analysis showed that Compound 1 was a noncompetitive inhibitor of α-glucosidase. Compounds 2 and 6 exhibited moderate inhibitory activities. Full article
Open AccessArticle Capgermacrenes A and B, Bioactive Secondary Metabolites from a Bornean Soft Coral, Capnella sp.
Mar. Drugs 2015, 13(5), 3103-3115; doi:10.3390/md13053103
Received: 23 February 2015 / Revised: 2 May 2015 / Accepted: 5 May 2015 / Published: 19 May 2015
Cited by 4 | PDF Full-text (659 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Two new bicyclogermacrenes, capgermacrenes A (1) and B (2), were isolated with two known compounds, palustrol (3) and litseagermacrane (4), from a population of Bornean soft coral Capnella sp. The structures of these metabolites were
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Two new bicyclogermacrenes, capgermacrenes A (1) and B (2), were isolated with two known compounds, palustrol (3) and litseagermacrane (4), from a population of Bornean soft coral Capnella sp. The structures of these metabolites were elucidated based on spectroscopic data. Compound 1 was found to inhibit the accumulation of the LPS-induced pro-inflammatory IL-1b and NO production by down-regulating the expression of iNOS protein in RAW 264.7 macrophages. Full article
(This article belongs to the Special Issue Marine Secondary Metabolites)
Open AccessArticle Design of Chitosan-Grafted Carbon Nanotubes: Evaluation of How the –OH Functional Group Affects Cs+ Adsorption
Mar. Drugs 2015, 13(5), 3116-3131; doi:10.3390/md13053116
Received: 10 October 2014 / Accepted: 17 December 2014 / Published: 20 May 2015
Cited by 6 | PDF Full-text (1011 KB) | HTML Full-text | XML Full-text
Abstract
In order to explore the effect of –OH functional groups in Cs+ adsorption, we herein used the low temperature plasma-induced grafting method to graft chitosan onto carbon nanotubes (denoted as CTS-g-CNTs), as raw-CNTs have few functional groups and chitosan has a large
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In order to explore the effect of –OH functional groups in Cs+ adsorption, we herein used the low temperature plasma-induced grafting method to graft chitosan onto carbon nanotubes (denoted as CTS-g-CNTs), as raw-CNTs have few functional groups and chitosan has a large number of –OH functional groups. The synthesized CTS-g-CNT composites were characterized using different techniques. The effect of –OH functional groups in the Cs+ adsorption process was evaluated by comparison of the adsorption properties of raw-CNTs with and without grafting chitosan. The variation of environmental conditions such as pH and contact time was investigated. A comparison of contaminated seawater and simulated groundwater was also evaluated. The results indicated that: (1) the adsorption of Cs+ ions was strongly dependent on pH and the competitive cations; (2) for CNT-based material, the –OH functional groups have a positive effect on Cs+ removal; (3) simulated contaminated groundwater can be used to model contaminated seawater to evaluate the adsorption property of CNTs-based material. These results showed direct observational evidence on the effect of –OH functional groups for Cs+ adsorption. Our findings are important in providing future directions to design and to choose effective material to remedy the removal of radioactive cesium from contaminated groundwater and seawater, crucial for public health and the human social environment. Full article
(This article belongs to the Special Issue Advances in Marine Chitin and Chitosan) Printed Edition available
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Open AccessArticle Tackling the Cytotoxic Effect of a Marine Polycyclic Quinone-Type Metabolite: Halenaquinone Induces Molt 4 Cells Apoptosis via Oxidative Stress Combined with the Inhibition of HDAC and Topoisomerase Activities
Mar. Drugs 2015, 13(5), 3132-3153; doi:10.3390/md13053132
Received: 5 March 2015 / Accepted: 7 May 2015 / Published: 20 May 2015
Cited by 1 | PDF Full-text (2435 KB) | HTML Full-text | XML Full-text
Abstract
A marine polycyclic quinone-type metabolite, halenaquinone (HQ), was found to inhibit the proliferation of Molt 4, K562, MDA-MB-231 and DLD-1 cancer cell lines, with IC50 of 0.48, 0.18, 8.0 and 6.76 μg/mL, respectively. It exhibited the most potent activity against leukemia Molt
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A marine polycyclic quinone-type metabolite, halenaquinone (HQ), was found to inhibit the proliferation of Molt 4, K562, MDA-MB-231 and DLD-1 cancer cell lines, with IC50 of 0.48, 0.18, 8.0 and 6.76 μg/mL, respectively. It exhibited the most potent activity against leukemia Molt 4 cells. Accumulating evidence showed that HQ may act as a potent protein kinase inhibitor in cancer therapy. To fully understand the mechanism of HQ, we further explored the precise molecular targets in leukemia Molt 4 cells. We found that the use of HQ increased apoptosis by 26.23%–70.27% and caused disruption of mitochondrial membrane potential (MMP) by 17.15%–53.25% in a dose-dependent manner, as demonstrated by Annexin-V/PI and JC-1 staining assays, respectively. Moreover, our findings indicated that the pretreatment of Molt 4 cells with N-acetyl-l-cysteine (NAC), a reactive oxygen species (ROS) scavenger, diminished MMP disruption and apoptosis induced by HQ, suggesting that ROS overproduction plays a crucial rule in the cytotoxic activity of HQ. The results of a cell-free system assay indicated that HQ could act as an HDAC and topoisomerase catalytic inhibitor through the inhibition of pan-HDAC and topoisomerase IIα expression, respectively. On the protein level, the expression of the anti-apoptotic proteins p-Akt, NFκB, HDAC and Bcl-2, as well as hexokinase II was inhibited by the use of HQ. On the other hand, the expression of the pro-apoptotic protein Bax, PARP cleavage, caspase activation and cytochrome c release were increased after HQ treatment. Taken together, our results suggested that the antileukemic effect of HQ is ROS-mediated mitochondrial apoptosis combined with the inhibitory effect on HDAC and topoisomerase activities. Full article
Open AccessArticle Determination of the Chemical Structures of Tandyukisins B–D, Isolated from a Marine Sponge-Derived Fungus
Mar. Drugs 2015, 13(5), 3231-3240; doi:10.3390/md13053231
Received: 18 March 2015 / Revised: 8 May 2015 / Accepted: 11 May 2015 / Published: 21 May 2015
Cited by 6 | PDF Full-text (386 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Tandyukisins B–D (13), novel decalin derivatives, have been isolated from a strain of Trichoderma harzianum OUPS-111D-4 originally derived from the marine sponge Halichondria okadai, and their structures have been elucidated on the basis of spectroscopic analyses using 1D
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Tandyukisins B–D (13), novel decalin derivatives, have been isolated from a strain of Trichoderma harzianum OUPS-111D-4 originally derived from the marine sponge Halichondria okadai, and their structures have been elucidated on the basis of spectroscopic analyses using 1D and 2D NMR techniques. In addition, their chemical structures were established by chemical transformation. They exhibited weak cytotoxicity, but selective growth inhibition on panel screening using 39 human cancer cell lines. Full article
Open AccessArticle Enhanced Control of Bladder-Associated Tumors Using Shrimp Anti-Lipopolysaccharide Factor (SALF) Antimicrobial Peptide as a Cancer Vaccine Adjuvant in Mice
Mar. Drugs 2015, 13(5), 3241-3258; doi:10.3390/md13053241
Received: 9 March 2015 / Accepted: 12 May 2015 / Published: 21 May 2015
Cited by 5 | PDF Full-text (2280 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Shrimp anti-lipopolysaccharide factor (SALF) is an antimicrobial peptide with reported anticancer activities, such as suppression of tumor progression. In this study, we prepared a potential cancer vaccine comprised of SALF in conjunction with the cell lysate of inactivated murine bladder carcinoma cells (MBT-2),
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Shrimp anti-lipopolysaccharide factor (SALF) is an antimicrobial peptide with reported anticancer activities, such as suppression of tumor progression. In this study, we prepared a potential cancer vaccine comprised of SALF in conjunction with the cell lysate of inactivated murine bladder carcinoma cells (MBT-2), and evaluated its efficacy in a mouse tumor model. Our study shows that SALF added to cell culture media inhibits growth progression of MBT-2, and that SALF together with inactivated MBT-2 lysate elevates the level of inflammasome activity, and modulates the levels of IL-1β, MCP-1, IL-6, IL-12, and TNF-α in mouse macrophages. Immunization of 7, 14, and 21 day-old mice with the vaccine prevented growth of MBT-2 cell-mediated tumors. The vaccine was found to enhance expression of T-cell, cytotoxic T cells, and NK cells in the immunized mice groups. Recruitment of macrophages, T-helper cells, and NK cells was enhanced, but levels of VEGF were decreased in immunized mice. This report provides empirical evidence that our SALF as vaccine adjuvant enhances antitumor immunity in mice. Full article
(This article belongs to the Special Issue Marine Peptides and Their Mimetics)

Review

Jump to: Research

Open AccessReview Diatom Milking: A Review and New Approaches
Mar. Drugs 2015, 13(5), 2629-2665; doi:10.3390/md13052629
Received: 10 December 2014 / Revised: 15 April 2015 / Accepted: 17 April 2015 / Published: 29 April 2015
Cited by 14 | PDF Full-text (809 KB) | HTML Full-text | XML Full-text | Correction | Supplementary Files
Abstract
The rise of human populations and the growth of cities contribute to the depletion of natural resources, increase their cost, and create potential climatic changes. To overcome difficulties in supplying populations and reducing the resource cost, a search for alternative pharmaceutical, nanotechnology, and
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The rise of human populations and the growth of cities contribute to the depletion of natural resources, increase their cost, and create potential climatic changes. To overcome difficulties in supplying populations and reducing the resource cost, a search for alternative pharmaceutical, nanotechnology, and energy sources has begun. Among the alternative sources, microalgae are the most promising because they use carbon dioxide (CO2) to produce biomass and/or valuable compounds. Once produced, the biomass is ordinarily harvested and processed (downstream program). Drying, grinding, and extraction steps are destructive to the microalgal biomass that then needs to be renewed. The extraction and purification processes generate organic wastes and require substantial energy inputs. Altogether, it is urgent to develop alternative downstream processes. Among the possibilities, milking invokes the concept that the extraction should not kill the algal cells. Therefore, it does not require growing the algae anew. In this review, we discuss research on milking of diatoms. The main themes are (a) development of alternative methods to extract and harvest high added value compounds; (b) design of photobioreactors; (c) biodiversity and (d) stress physiology, illustrated with original results dealing with oleaginous diatoms. Full article
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Open AccessReview Recent Advances and Applications of Experimental Technologies in Marine Natural Product Research
Mar. Drugs 2015, 13(5), 2694-2713; doi:10.3390/md13052694
Received: 12 January 2015 / Revised: 2 April 2015 / Accepted: 14 April 2015 / Published: 29 April 2015
Cited by 5 | PDF Full-text (994 KB) | HTML Full-text | XML Full-text
Abstract
Marine natural products are a rich source of novel and biologically active compounds. The number of identified marine natural compounds has grown 20% over the last five years from 2009 to 2013. Several challenges, including sample collection and structure elucidation, have limited the
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Marine natural products are a rich source of novel and biologically active compounds. The number of identified marine natural compounds has grown 20% over the last five years from 2009 to 2013. Several challenges, including sample collection and structure elucidation, have limited the development of this research field. Nonetheless, new approaches, such as sampling strategies for organisms from extreme ocean environments, nanoscale NMR and computational chemistry for structural determination, are now available to overcome the barriers. In this review, we highlight the experimental technology innovations in the field of marine natural products, which in our view will lead to the development of many new drugs in the future. Full article
Open AccessReview Perspective on the Use of Sulfated Polysaccharides from Marine Organisms as a Source of New Antithrombotic Drugs
Mar. Drugs 2015, 13(5), 2770-2784; doi:10.3390/md13052770
Received: 26 February 2015 / Revised: 14 April 2015 / Accepted: 17 April 2015 / Published: 6 May 2015
Cited by 21 | PDF Full-text (1546 KB) | HTML Full-text | XML Full-text
Abstract
Thromboembolic diseases are increasing worldwide and always require anticoagulant therapy. We still need safer and more secure antithrombotic drugs than those presently available. Sulfated polysaccharides from marine organisms may constitute a new source for the development of such drugs. Investigation of these compounds
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Thromboembolic diseases are increasing worldwide and always require anticoagulant therapy. We still need safer and more secure antithrombotic drugs than those presently available. Sulfated polysaccharides from marine organisms may constitute a new source for the development of such drugs. Investigation of these compounds usually attempts to reproduce the therapeutic effects of heparin. However, we may need to follow different routes, focusing particularly in the following aspects: (1) defining precisely the specific structures required for interaction of these sulfated polysaccharides with proteins of the coagulation system; (2) looking for alternative mechanisms of action, distinct from those of heparin; (3) identifying side effects (mostly pro-coagulant action and hypotension rather than bleeding) and preparing derivatives that retain the desired antithrombotic action but are devoid of side effects; (4) considering that sulfated polysaccharides with low anticoagulant action on in vitro assays may display potent effects on animal models of experimental thrombosis; and finally (5) investigating the antithrombotic effect of these sulfated polysaccharides after oral administration or preparing derivatives that may achieve this effect. If these aspects are successfully addressed, sulfated polysaccharides from marine organisms may conquer the frontier of antithrombotic therapy and open new avenues for treatment or prevention of thromboembolic diseases. Full article
(This article belongs to the collection Marine Polysaccharides)
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Open AccessReview Sea Cucumbers Metabolites as Potent Anti-Cancer Agents
Mar. Drugs 2015, 13(5), 2909-2923; doi:10.3390/md13052909
Received: 17 February 2015 / Revised: 16 April 2015 / Accepted: 28 April 2015 / Published: 12 May 2015
Cited by 11 | PDF Full-text (490 KB) | HTML Full-text | XML Full-text
Abstract
Sea cucumbers and their extracts have gained immense popularity and interest among researchers and nutritionists due to their nutritive value, potential health benefits, and use in the treatment of chronic inflammatory diseases. Many areas of the world use sea cucumbers in traditional foods
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Sea cucumbers and their extracts have gained immense popularity and interest among researchers and nutritionists due to their nutritive value, potential health benefits, and use in the treatment of chronic inflammatory diseases. Many areas of the world use sea cucumbers in traditional foods and folk medicine. Though the actual components and their specific functions still remain to be investigated, most sea cucumber extracts are being studied for their anti-inflammatory functions, immunostimulatory properties, and for cancer prevention and treatment. There is large scope for the discovery of additional bioactive, valuable compounds from this natural source. Sea cucumber extracts contain unique components, such as modified triterpene glycosides, sulfated polysaccharides, glycosphingolipids, and esterified phospholipids. Frondanol A5, an isopropyl alcohol/water extract of the enzymatically hydrolyzed epithelia of the edible North Atlantic sea cucumber, Cucumaria frondosa, contains monosulfated triterpenoid glycoside Frondoside A, the disulfated glycoside Frondoside B, the trisulfated glycoside Frondoside C, 12-methyltetradecanoic acid, eicosapentaenoic acid, and fucosylated chondroitin sulfate. We have extensively studied the efficacy of this extract in preventing colon cancer in rodent models. In this review, we discuss the anti-inflammatory, immunostimulatory, and anti-tumor properties of sea cucumber extracts. Full article
Open AccessReview Emerging Concepts Promising New Horizons for Marine Biodiscovery and Synthetic Biology
Mar. Drugs 2015, 13(5), 2924-2954; doi:10.3390/md13052924
Received: 18 March 2015 / Revised: 22 April 2015 / Accepted: 28 April 2015 / Published: 13 May 2015
Cited by 20 | PDF Full-text (1331 KB) | HTML Full-text | XML Full-text
Abstract
The vast oceans of the world, which comprise a huge variety of unique ecosystems, are emerging as a rich and relatively untapped source of novel bioactive compounds with invaluable biotechnological and pharmaceutical potential. Evidence accumulated over the last decade has revealed that the
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The vast oceans of the world, which comprise a huge variety of unique ecosystems, are emerging as a rich and relatively untapped source of novel bioactive compounds with invaluable biotechnological and pharmaceutical potential. Evidence accumulated over the last decade has revealed that the diversity of marine microorganisms is enormous with many thousands of bacterial species detected that were previously unknown. Associated with this diversity is the production of diverse repertoires of bioactive compounds ranging from peptides and enzymes to more complex secondary metabolites that have significant bioactivity and thus the potential to be exploited for innovative biotechnology. Here we review the discovery and functional potential of marine bioactive peptides such as lantibiotics, nanoantibiotics and peptidomimetics, which have received particular attention in recent years in light of their broad spectrum of bioactivity. The significance of marine peptides in cell-to-cell communication and how this may be exploited in the discovery of novel bioactivity is also explored. Finally, with the recent advances in bioinformatics and synthetic biology, it is becoming clear that the integration of these disciplines with genetic and biochemical characterization of the novel marine peptides, offers the most potential in the development of the next generation of societal solutions. Full article
(This article belongs to the Special Issue Marine Peptides and Their Mimetics)
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Open AccessReview Marine Polysaccharides from Algae with Potential Biomedical Applications
Mar. Drugs 2015, 13(5), 2967-3028; doi:10.3390/md13052967
Received: 10 March 2015 / Revised: 26 April 2015 / Accepted: 4 May 2015 / Published: 15 May 2015
Cited by 53 | PDF Full-text (1425 KB) | HTML Full-text | XML Full-text
Abstract
There is a current tendency towards bioactive natural products with applications in various industries, such as pharmaceutical, biomedical, cosmetics and food. This has put some emphasis in research on marine organisms, including macroalgae and microalgae, among others. Polysaccharides with marine origin constitute one
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There is a current tendency towards bioactive natural products with applications in various industries, such as pharmaceutical, biomedical, cosmetics and food. This has put some emphasis in research on marine organisms, including macroalgae and microalgae, among others. Polysaccharides with marine origin constitute one type of these biochemical compounds that have already proved to have several important properties, such as anticoagulant and/or antithrombotic, immunomodulatory ability, antitumor and cancer preventive, antilipidaemic and hypoglycaemic, antibiotics and anti-inflammatory and antioxidant, making them promising bioactive products and biomaterials with a wide range of applications. Their properties are mainly due to their structure and physicochemical characteristics, which depend on the organism they are produced by. In the biomedical field, the polysaccharides from algae can be used in controlled drug delivery, wound management, and regenerative medicine. This review will focus on the biomedical applications of marine polysaccharides from algae. Full article
(This article belongs to the collection Marine Polysaccharides)
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Open AccessReview Molecular Architecture and Biomedical Leads of Terpenes from Red Sea Marine Invertebrates
Mar. Drugs 2015, 13(5), 3154-3181; doi:10.3390/md13053154
Received: 9 April 2015 / Revised: 5 May 2015 / Accepted: 7 May 2015 / Published: 20 May 2015
Cited by 12 | PDF Full-text (1162 KB) | HTML Full-text | XML Full-text
Abstract
Marine invertebrates including sponges, soft coral, tunicates, mollusks and bryozoan have proved to be a prolific source of bioactive natural products. Among marine-derived metabolites, terpenoids have provided a vast array of molecular architectures. These isoprenoid-derived metabolites also exhibit highly specialized biological activities ranging
[...] Read more.
Marine invertebrates including sponges, soft coral, tunicates, mollusks and bryozoan have proved to be a prolific source of bioactive natural products. Among marine-derived metabolites, terpenoids have provided a vast array of molecular architectures. These isoprenoid-derived metabolites also exhibit highly specialized biological activities ranging from nerve regeneration to blood-sugar regulation. As a result, intense research activity has been devoted to characterizing invertebrate terpenes from both a chemical and biological standpoint. This review focuses on the chemistry and biology of terpene metabolites isolated from the Red Sea ecosystem, a unique marine biome with one of the highest levels of biodiversity and specifically rich in invertebrate species. Full article
(This article belongs to the Special Issue Marine Secondary Metabolites)
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Open AccessReview Alternative and Efficient Extraction Methods for Marine-Derived Compounds
Mar. Drugs 2015, 13(5), 3182-3230; doi:10.3390/md13053182
Received: 20 April 2015 / Revised: 1 May 2015 / Accepted: 6 May 2015 / Published: 21 May 2015
Cited by 16 | PDF Full-text (424 KB) | HTML Full-text | XML Full-text
Abstract
Marine ecosystems cover more than 70% of the globe’s surface. These habitats are occupied by a great diversity of marine organisms that produce highly structural diverse metabolites as a defense mechanism. In the last decades, these metabolites have been extracted and isolated in
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Marine ecosystems cover more than 70% of the globe’s surface. These habitats are occupied by a great diversity of marine organisms that produce highly structural diverse metabolites as a defense mechanism. In the last decades, these metabolites have been extracted and isolated in order to test them in different bioassays and assess their potential to fight human diseases. Since traditional extraction techniques are both solvent- and time-consuming, this review emphasizes alternative extraction techniques, such as supercritical fluid extraction, pressurized solvent extraction, microwave-assisted extraction, ultrasound-assisted extraction, pulsed electric field-assisted extraction, enzyme-assisted extraction, and extraction with switchable solvents and ionic liquids, applied in the search for marine compounds. Only studies published in the 21st century are considered. Full article

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