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Mar. Drugs, Volume 14, Issue 10 (October 2016)

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Editorial

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Open AccessEditorial Promise from the Sea
Mar. Drugs 2016, 14(10), 178; doi:10.3390/md14100178
Received: 29 August 2016 / Accepted: 24 September 2016 / Published: 9 October 2016
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Abstract
The twenty-first century’s greatestmedical challenge is degenerative disease. [...] Full article
(This article belongs to the Special Issue Marine Compounds and Their Application in Neurological Disorders)

Research

Jump to: Editorial, Review

Open AccessArticle Bioactive Chaetoglobosins from the Mangrove Endophytic Fungus Penicillium chrysogenum
Mar. Drugs 2016, 14(10), 172; doi:10.3390/md14100172
Received: 27 August 2016 / Revised: 19 September 2016 / Accepted: 21 September 2016 / Published: 27 September 2016
Cited by 3 | PDF Full-text (1510 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
A novel chaetoglobosin named penochalasin I (1) with a unprecedented six-cyclic 6/5/6/5/6/13 fused ring system, and another new chaetoglobosin named penochalasin J (2), along with chaetoglobosins G, F, C, A, E, armochaetoglobosin I, and cytoglobosin C (3
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A novel chaetoglobosin named penochalasin I (1) with a unprecedented six-cyclic 6/5/6/5/6/13 fused ring system, and another new chaetoglobosin named penochalasin J (2), along with chaetoglobosins G, F, C, A, E, armochaetoglobosin I, and cytoglobosin C (39) were isolated from the culture of Penicillium chrysogenum V11. Their structures were elucidated by 1D, 2D NMR spectroscopic analysis and high resolution mass spectroscopic data. The absolute configuration of compounds 1 and 2 were determined by comparing the theoretical electronic circular dichroism (ECD) calculation with the experimental CD. Compound 1 was the first example, with a six-cyclic fused ring system formed by the connection of C-5 and C-2′ of the chaetoglobosin class. Compounds 58 remarkably inhibited the plant pathogenic fungus R. solani (minimum inhibitory concentrations (MICs) = 11.79–23.66 μM), and compounds 2, 6, and 7 greatly inhibited C. gloeosporioides (MICs = 23.58–47.35 μM), showing an antifungal activity higher than that of carbendazim. Compound 1 exhibited marked cytotoxicity against MDA-MB-435 and SGC-7901 cells (IC50 < 10 μM), and compounds 6 and 9 showed potent cytotoxicity against SGC-7901 and A549 cells (IC50 < 10 μM). Full article
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Open AccessArticle Novel Spray Dried Glycerol 2-Phosphate Cross-Linked Chitosan Microparticulate Vaginal Delivery System—Development, Characterization and Cytotoxicity Studies
Mar. Drugs 2016, 14(10), 174; doi:10.3390/md14100174
Received: 9 August 2016 / Revised: 13 September 2016 / Accepted: 14 September 2016 / Published: 28 September 2016
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Abstract
Chitosan microparticulate delivery systems containing clotrimazole were prepared by a spray drying technique using glycerol 2-phosphate as an ion cross-linker. The impact of a cross-linking ratio on microparticle characteristics was evaluated. Drug-free and drug-loaded unmodified or ion cross-linked chitosan microparticles were examined for
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Chitosan microparticulate delivery systems containing clotrimazole were prepared by a spray drying technique using glycerol 2-phosphate as an ion cross-linker. The impact of a cross-linking ratio on microparticle characteristics was evaluated. Drug-free and drug-loaded unmodified or ion cross-linked chitosan microparticles were examined for the in vitro cytotoxicity in VK2/E6E7 human vaginal epithelial cells. The presence of glycerol 2-phosphate influenced drug loading and encapsulation efficacy in chitosan microparticles. By increasing the cross-linking ratio, the microparticles with lower diameter, moisture content and smoother surface were observed. Mucoadhesive studies displayed that all formulations possessed mucoadhesive properties. The in vitro release profile of clotrimazole was found to alter considerably by changing the glycerol 2-phosphate/chitosan ratio. Results from cytotoxicity studies showed occurrence of apoptotic cells in the presence of chitosan and ion cross-linked chitosan microparticles, followed by a loss of membrane potential suggesting that cell death might go through the mitochondrial apoptotic pathway. Full article
(This article belongs to the Special Issue Advances in Marine Chitin and Chitosan II, 2017)
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Open AccessArticle Controlling Properties and Cytotoxicity of Chitosan Nanocapsules by Chemical Grafting
Mar. Drugs 2016, 14(10), 175; doi:10.3390/md14100175
Received: 28 July 2016 / Revised: 14 September 2016 / Accepted: 20 September 2016 / Published: 30 September 2016
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Abstract
The tunability of the properties of chitosan-based carriers opens new ways for the application of drugs with low water-stability or high adverse effects. In this work, the combination of a nanoemulsion with a chitosan hydrogel coating and the following poly (ethylene glycol) (PEG)
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The tunability of the properties of chitosan-based carriers opens new ways for the application of drugs with low water-stability or high adverse effects. In this work, the combination of a nanoemulsion with a chitosan hydrogel coating and the following poly (ethylene glycol) (PEG) grafting is proven to be a promising strategy to obtain a flexible and versatile nanocarrier with an improved stability. Thanks to chitosan amino groups, a new easy and reproducible method to obtain nanocapsule grafting with PEG has been developed in this work, allowing a very good control and tunability of the properties of nanocapsule surface. Two different PEG densities of coverage are studied and the nanocapsule systems obtained are characterized at all steps of the optimization in terms of diameter, Z potential and surface charge (amino group analysis). Results obtained are compatible with a conformation of PEG molecules laying adsorbed on nanoparticle surface after covalent linking through their amino terminal moiety. An improvement in nanocapsule stability in physiological medium is observed with the highest PEG coverage density obtained. Cytotoxicity tests also demonstrate that grafting with PEG is an effective strategy to modulate the cytotoxicity of developed nanocapsules. Such results indicate the suitability of chitosan as protective coating for future studies oriented toward drug delivery. Full article
(This article belongs to the Special Issue Advances in Marine Chitin and Chitosan II, 2017)
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Open AccessArticle Angiotensin-I Converting Enzyme (ACE) Inhibitory and Anti-Hypertensive Effect of Protein Hydrolysate from Actinopyga lecanora (Sea Cucumber) in Rats
Mar. Drugs 2016, 14(10), 176; doi:10.3390/md14100176
Received: 2 March 2016 / Revised: 8 July 2016 / Accepted: 19 July 2016 / Published: 30 September 2016
Cited by 1 | PDF Full-text (1918 KB) | HTML Full-text | XML Full-text
Abstract
Food protein hydrolysates are known to exhibit angiotensin converting enzyme (ACE) inhibitory properties and can be used as a novel functional food for prevention of hypertension. This study evaluated the ACE inhibitory potentials of Actinopyga lecanora proteolysate (ALP) in vivo. The pre-fed rats
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Food protein hydrolysates are known to exhibit angiotensin converting enzyme (ACE) inhibitory properties and can be used as a novel functional food for prevention of hypertension. This study evaluated the ACE inhibitory potentials of Actinopyga lecanora proteolysate (ALP) in vivo. The pre-fed rats with ALP at various doses (200, 400, 800 mg/kg body weight) exhibited a significant (p ≤ 0.05) suppression effect after inducing hypertension. To determine the optimum effective dose that will produce maximal reduction in blood pressure, ALP at three doses was fed to the rats after inducing hypertension. The results showed that the 800 mg/kg body weight dose significantly reduced blood pressure without noticeable negative physiological effect. In addition, there were no observable changes in the rats’ heart rate after oral administration of the ALP. It was concluded that Actinopyga lecanora proteolysate could potentially be used for the development of functional foods and nutraceuticals for prevention and treatment of hypertension. Full article
(This article belongs to the collection Bioactive Compounds from Marine Invertebrates)
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Open AccessArticle Dihydroisocoumarins from the Mangrove-Derived Fungus Penicillium citrinum
Mar. Drugs 2016, 14(10), 177; doi:10.3390/md14100177
Received: 3 August 2016 / Revised: 17 September 2016 / Accepted: 28 September 2016 / Published: 10 October 2016
Cited by 1 | PDF Full-text (1781 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Three new dihydroisocoumarin penicimarins G–I (13), together with one known dihydroisocoumarin (4) and three known meroterpenoids (57), were obtained from a fungus Penicillium citrinum isolated from the mangrove Bruguiera sexangula var. rhynchopetala collected
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Three new dihydroisocoumarin penicimarins G–I (13), together with one known dihydroisocoumarin (4) and three known meroterpenoids (57), were obtained from a fungus Penicillium citrinum isolated from the mangrove Bruguiera sexangula var. rhynchopetala collected in the South China Sea. Their structures were elucidated by the detailed analysis of spectroscopic data. The absolute configuration of 1 was determined by the X-ray diffraction analysis using Cu Kα radiation. The absolute configurations of 2 and 3 were determined by comparison of their circular dichroism (CD) spectra with the literature. All compounds were evaluated for their antibacterial activities and cytotoxic activities. Full article
(This article belongs to the Special Issue Marine Fungal Natural Products)
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Open AccessArticle Erylusamides: Novel Atypical Glycolipids from Erylus cf. deficiens
Mar. Drugs 2016, 14(10), 179; doi:10.3390/md14100179
Received: 11 July 2016 / Revised: 2 September 2016 / Accepted: 15 September 2016 / Published: 11 October 2016
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Abstract
Among marine organisms, sponges are the richest sources of pharmacologically-active compounds. Stemming from a previous lead discovery program that gathered a comprehensive library of organic extracts of marine sponges from the off-shore region of Portugal, crude extracts of Erylus cf. deficiens collected
[...] Read more.
Among marine organisms, sponges are the richest sources of pharmacologically-active compounds. Stemming from a previous lead discovery program that gathered a comprehensive library of organic extracts of marine sponges from the off-shore region of Portugal, crude extracts of Erylus cf. deficiens collected in the Gorringe Bank (Atlantic Ocean) were tested in the innovative high throughput screening (HTS) assay for inhibitors of indoleamine 2,3-dioxygenase (IDO) and showed activity. Bioassay guided fractionation of the dichloromethane extract led to the isolation of four new glycolipids, named erylusamide AD. The structures of the isolated compounds were established by 1D and 2D nuclear magnetic resonance (NMR) spectroscopy, high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) and chemical derivatization. The metabolites shared a pentasaccharide moiety constituted by unusual highly acetylated ᴅ-glucose moieties as well as ᴅ-xylose and ᴅ-galactose. The aglycones were unprecedented long chain dihydroxyketo amides. Erylusamides A, B and D differ in the length of the hydrocarbon chain, while erylusamide C is a structural isomer of erylusamide B. Full article
(This article belongs to the Special Issue Deep-Sea Natural Products)
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Open AccessArticle Bioactive Steroids from the Formosan Soft Coral Umbellulifera petasites
Mar. Drugs 2016, 14(10), 180; doi:10.3390/md14100180
Received: 31 August 2016 / Revised: 19 September 2016 / Accepted: 21 September 2016 / Published: 11 October 2016
Cited by 6 | PDF Full-text (1500 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Three new steroids, petasitosterones A and B (1 and 2) and a spirosteroid petasitosterone C (3), along with eight known steroids (411), were isolated from a Formosan marine soft coral Umbellulifera petasites. The structures
[...] Read more.
Three new steroids, petasitosterones A and B (1 and 2) and a spirosteroid petasitosterone C (3), along with eight known steroids (411), were isolated from a Formosan marine soft coral Umbellulifera petasites. The structures of these compounds were elucidated by extensive spectroscopic analysis and comparison of spectroscopic data with those reported. Compound 3 is a marine steroid with a rarely found A/B spiro[4,5]decane ring system. Compounds 13 and 5 displayed inhibitory activity against the proliferation of a limited panel of cancer cell lines, whereas 2 and 5 exhibited significant anti-inflammatory activity to inhibit nitric oxide (NO) production. The inhibitory activities for superoxide anion generation and elastase release of compounds 111 were also examined to evaluate the anti-inflammatory potential, and 24 were shown to exhibit significant activities. Full article
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Open AccessArticle New Metabolites and Bioactive Actinomycins from Marine-Derived Streptomyces sp. ZZ338
Mar. Drugs 2016, 14(10), 181; doi:10.3390/md14100181
Received: 21 August 2016 / Revised: 20 September 2016 / Accepted: 21 September 2016 / Published: 11 October 2016
Cited by 3 | PDF Full-text (804 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
An extract prepared from the culture of a marine-derived actinomycete Streptomyces sp. ZZ338 was found to have significant antimicrobial and antiproliferative activities. A chemical investigation of this active extract resulted in the isolation of three known bioactive actinomycins (13)
[...] Read more.
An extract prepared from the culture of a marine-derived actinomycete Streptomyces sp. ZZ338 was found to have significant antimicrobial and antiproliferative activities. A chemical investigation of this active extract resulted in the isolation of three known bioactive actinomycins (13) and two new metabolites (4 and 5). The structures of the isolated compounds were identified as actinomycins D (1), V (2), X (3), 2-acetylamino-3-hydroxyl-4-methyl-benzoic acid methyl ester (4), and N-1S-(4-methylaminophenylmethyl)-2-oxo-propyl acetamide (5) based on their nuclear magnetic resonance (NMR) and high resolution electrospray ionization mass spectroscopy (HRESIMS) data as well as their optical rotation. This class of new compound 5 had never before been found from a natural resource. Three known actinomycins showed activities in inhibiting the proliferation of glioma cells and the growth of methicillin-resistant Staphylococcus aureus, Escherichia coli, and Candida albicans and are responsible for the activity of the crude extract. Actinomycin D (1) was also found to downregulate several glioma metabolic enzymes of glycolysis, glutaminolysis, and lipogenesis, suggesting that targeting multiple tumor metabolic regulators might be a new anti-glioma mechanism of actinomycin D. This is the first report of such a possible mechanism for the class of actinomycins. Full article
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Open AccessArticle Development and Characterization of VEGF165-Chitosan Nanoparticles for the Treatment of Radiation-Induced Skin Injury in Rats
Mar. Drugs 2016, 14(10), 182; doi:10.3390/md14100182
Received: 12 August 2016 / Revised: 30 August 2016 / Accepted: 31 August 2016 / Published: 11 October 2016
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Abstract
Radiation-induced skin injury, which remains a serious concern in radiation therapy, is currently believed to be the result of vascular endothelial cell injury and apoptosis. Here, we established a model of acute radiation-induced skin injury and compared the effect of different vascular growth
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Radiation-induced skin injury, which remains a serious concern in radiation therapy, is currently believed to be the result of vascular endothelial cell injury and apoptosis. Here, we established a model of acute radiation-induced skin injury and compared the effect of different vascular growth factors on skin healing by observing the changes of microcirculation and cell apoptosis. Vascular endothelial growth factor (VEGF) was more effective at inhibiting apoptosis and preventing injury progression than other factors. A new strategy for improving the bioavailability of vascular growth factors was developed by loading VEGF with chitosan nanoparticles. The VEGF-chitosan nanoparticles showed a protective effect on vascular endothelial cells, improved the local microcirculation, and delayed the development of radioactive skin damage. Full article
(This article belongs to the Special Issue Advances in Marine Chitin and Chitosan II, 2017)
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Open AccessArticle Conversion of Squid Pen to Homogentisic Acid via Paenibacillus sp. TKU036 and the Antioxidant and Anti-Inflammatory Activities of Homogentisic Acid
Mar. Drugs 2016, 14(10), 183; doi:10.3390/md14100183
Received: 14 September 2016 / Revised: 5 October 2016 / Accepted: 7 October 2016 / Published: 12 October 2016
Cited by 2 | PDF Full-text (2041 KB) | HTML Full-text | XML Full-text
Abstract
The culture supernatant of Paenibacillus sp. TKU036, a bacterium isolated from Taiwanese soils, showed high antioxidant activity (85%) when cultured in a squid pen powder (SPP)-containing medium at 37 °C for three days. Homogentisic acid (2,5-dihydroxyphenylacetic acid, HGA) was isolated and found to
[...] Read more.
The culture supernatant of Paenibacillus sp. TKU036, a bacterium isolated from Taiwanese soils, showed high antioxidant activity (85%) when cultured in a squid pen powder (SPP)-containing medium at 37 °C for three days. Homogentisic acid (2,5-dihydroxyphenylacetic acid, HGA) was isolated and found to be the major antioxidant in the culture supernatant of the SPP-containing medium fermented by Paenibacillus sp. TKU036. Tryptophan was also present in the culture supernatant. The results of high-performance liquid chromatography (HPLC) fingerprinting showed that HGA and tryptophan were produced via fermentation but did not pre-exist in the unfermented SPP-containing medium. Neither HGA nor tryptophan was found in the culture supernatants obtained from the fermentation of nutrient broth or other chitinous material, i.e., medium containing shrimp head powder, by Paenibacillus sp. TKU036. The production of HGA via microorganisms has rarely been reported. In this study, we found that squid pen was a potential carbon and nitrogen source for Paenibacillus sp. Tryptophan (105 mg/L) and HGA (60 mg/L) were recovered from the culture supernatant. The isolated HGA was found to have higher antioxidant activity (IC50 = 6.9 μg/mL) than α-tocopherol (IC50 = 17.6 μg/mL). The anti-inflammatory activity of the isolated HGA (IC50 = 10.14 μg/mL) was lower than that of quercetin (IC50 = 1.14 μg/mL). As a result, squid pen, a fishery processing byproduct, is a valuable material for the production of tryptophan and the antioxidant and anti-inflammatory HGA via microbial conversion. Full article
(This article belongs to the Special Issue Advances in Marine Chitin and Chitosan II, 2017)
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Open AccessCommunication A New Dioic Acid from a wbl Gene Mutant of Deepsea-Derived Streptomyces somaliensis SCSIO ZH66
Mar. Drugs 2016, 14(10), 184; doi:10.3390/md14100184
Received: 20 September 2016 / Revised: 1 October 2016 / Accepted: 8 October 2016 / Published: 17 October 2016
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Abstract
The wblAso gene functions as a global regulatory gene in a negative manner in deepsea-derived Streptomyces somaliensis SCSIO ZH66. A new dioic acid (1) as well as two known butenolides (2 and 3) were isolated from the ΔwblA
[...] Read more.
The wblAso gene functions as a global regulatory gene in a negative manner in deepsea-derived Streptomyces somaliensis SCSIO ZH66. A new dioic acid (1) as well as two known butenolides (2 and 3) were isolated from the ΔwblAso mutant strain of S. somaliensis SCSIO ZH66. The structure of 1 was elucidated by a combination of spectroscopic analyses, including MS and NMR techniques. In the cell growth inhibitory evaluation, compound 3 exhibited moderate activity against the human hepatic carcinoma cell line (Huh7.5) with an IC50 value of 19.4 μg/mL, while compounds 1 and 2 showed null activity up to 100 μg/mL. Full article
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Open AccessArticle Identification of a Pro-Angiogenic Potential and Cellular Uptake Mechanism of a LMW Highly Sulfated Fraction of Fucoidan from Ascophyllum nodosum
Mar. Drugs 2016, 14(10), 185; doi:10.3390/md14100185
Received: 28 September 2016 / Revised: 28 September 2016 / Accepted: 10 October 2016 / Published: 17 October 2016
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Abstract
Herein we investigate the structure/function relationships of fucoidans from Ascophyllum nodosum to analyze their pro-angiogenic effect and cellular uptake in native and glycosaminoglycan-free (GAG-free) human endothelial cells (HUVECs). Fucoidans are marine sulfated polysaccharides, which act as glycosaminoglycans mimetics. We hypothesized that the size
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Herein we investigate the structure/function relationships of fucoidans from Ascophyllum nodosum to analyze their pro-angiogenic effect and cellular uptake in native and glycosaminoglycan-free (GAG-free) human endothelial cells (HUVECs). Fucoidans are marine sulfated polysaccharides, which act as glycosaminoglycans mimetics. We hypothesized that the size and sulfation rate of fucoidans influence their ability to induce pro-angiogenic processes independently of GAGs. We collected two fractions of fucoidans, Low and Medium Molecular Weight Fucoidan (LMWF and MMWF, respectively) by size exclusion chromatography and characterized their composition (sulfate, fucose and uronic acid) by colorimetric measurement and Raman and FT-IR spectroscopy. The high affinities of fractionated fucoidans to heparin binding proteins were confirmed by Surface Plasmon Resonance. We evidenced that LMWF has a higher pro-angiogenic (2D-angiogenesis on Matrigel) and pro-migratory (Boyden chamber) potential on HUVECs, compared to MMWF. Interestingly, in a GAG-free HUVECs model, LMWF kept a pro-angiogenic potential. Finally, to evaluate the association of LMWF-induced biological effects and its cellular uptake, we analyzed by confocal microscopy the GAGs involvement in the internalization of a fluorescent LMWF. The fluorescent LMWF was mainly internalized through HUVEC clathrin-dependent endocytosis in which GAGs were partially involved. In conclusion, a better characterization of the relationships between the fucoidan structure and its pro-angiogenic potential in GAG-free endothelial cells was required to identify an adapted fucoidan to enhance vascular repair in ischemia. Full article
(This article belongs to the collection Marine Polysaccharides)
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Open AccessArticle Purification of Antioxidant Peptides by High Resolution Mass Spectrometry from Simulated Gastrointestinal Digestion Hydrolysates of Alaska Pollock (Theragra chalcogramma) Skin Collagen
Mar. Drugs 2016, 14(10), 186; doi:10.3390/md14100186
Received: 14 July 2016 / Revised: 20 September 2016 / Accepted: 26 September 2016 / Published: 17 October 2016
Cited by 3 | PDF Full-text (3241 KB) | HTML Full-text | XML Full-text
Abstract
In this study, the stable collagen hydrolysate was prepared by alcalase hydrolysis and twice simulated gastrointestinal digestion from Alaska pollock skin. The characteristics of hydrolysates and antioxidant activities in vitro, including 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical (ABTS•+) scavenging activity, ferric-reducing antioxidant power
[...] Read more.
In this study, the stable collagen hydrolysate was prepared by alcalase hydrolysis and twice simulated gastrointestinal digestion from Alaska pollock skin. The characteristics of hydrolysates and antioxidant activities in vitro, including 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical (ABTS•+) scavenging activity, ferric-reducing antioxidant power (FRAP) and hydroxyl radical (OH·) scavenging activity, were determined. After twice simulated gastrointestinal digestion of skin collagen (SGI-2), the degree of hydrolysis (DH) reached 26.17%. The main molecular weight fractions of SGI-2 were 1026.26 and 640.53 Da, accounting for 59.49% and 18.34%, respectively. Amino acid composition analysis showed that SGI-2 had high content of total hydrophobic amino acid (307.98/1000). With the simulated gastrointestinal digestion progressing, the antioxidant activities increased significantly (p < 0.05). SGI-2 was further purified by gel filtration chromatography, ion exchange chromatography and high performance liquid chromatography, and the A1a3c–p fraction with high hydroxyl radical scavenging activity (IC50 = 7.63 μg/mL) was obtained. The molecular weights and amino acid sequences of key peptides of A1a3c–p were analyzed using high resolution mass spectrometry (LC-ESI-LTQ-Orbitrap-MS) combined with de novo software and UniProt of MaxQuant software. Four peptides were identified from A1a3c–p, including YGCC (444.1137 Da) and DSSCSG (554.1642 Da) identified by de novo software and NNAEYYK (900.3978 Da) and PAGNVR (612.3344 Da) identified by UniProt of MaxQuant software. The molecular weights and amino acid sequences of four peptides were in accordance with the features of antioxidant peptides. The results indicated that different peptides were identified by different data analysis software according to spectrometry mass data. Considering the complexity of LC-ESI-LTQ-Orbitrap-MS, it was necessary to use the different methods to identify the key peptides from protein hydrolysates. Full article
(This article belongs to the Special Issue Marine Proteins and Peptides)
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Open AccessArticle Neuroprotective Effect of the Marine-Derived Compound 11-Dehydrosinulariolide through DJ-1-Related Pathway in In Vitro and In Vivo Models of Parkinson’s Disease
Mar. Drugs 2016, 14(10), 187; doi:10.3390/md14100187
Received: 27 August 2016 / Revised: 1 October 2016 / Accepted: 8 October 2016 / Published: 17 October 2016
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Abstract
Parkinson’s disease (PD) is a neurodegenerative disorder characterized by tremor, rigidity, bradykinesia, and gait impairment. In a previous study, we found that the marine-derived compound 11-dehydrosinulariolide (11-de) upregulates the Akt/PI3K pathway to protect cells against 6-hydroxydopamine (6-OHDA)-mediated damage. In the present study, SH-SY5Y,
[...] Read more.
Parkinson’s disease (PD) is a neurodegenerative disorder characterized by tremor, rigidity, bradykinesia, and gait impairment. In a previous study, we found that the marine-derived compound 11-dehydrosinulariolide (11-de) upregulates the Akt/PI3K pathway to protect cells against 6-hydroxydopamine (6-OHDA)-mediated damage. In the present study, SH-SY5Y, zebrafish and rats were used to examine the therapeutic effect of 11-de. The results revealed the mechanism by which 11-de exerts its therapeutic effect: the compound increases cytosolic or mitochondrial DJ-1 expression, and then activates the downstream Akt/PI3K, p-CREB, and Nrf2/HO-1 pathways. Additionally, we found that 11-de could reverse the 6-OHDA-induced downregulation of total swimming distance in a zebrafish model of PD. Using a rat model of PD, we showed that a 6-OHDA-induced increase in the number of turns, and increased time spent by rats on the beam, could be reversed by 11-de treatment. Lastly, we showed that 6-OHDA-induced attenuation in tyrosine hydroxylase (TH), a dopaminergic neuronal marker, in zebrafish and rat models of PD could also be reversed by treatment with 11-de. Moreover, the patterns of DJ-1 expression observed in this study in the zebrafish and rat models of PD corroborated the trend noted in previous in vitro studies. Full article
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Open AccessArticle MDN-0170, a New Napyradiomycin from Streptomyces sp. Strain CA-271078
Mar. Drugs 2016, 14(10), 188; doi:10.3390/md14100188
Received: 11 August 2016 / Revised: 29 September 2016 / Accepted: 13 October 2016 / Published: 18 October 2016
Cited by 1 | PDF Full-text (1392 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
A new napyradiomycin, MDN-0170 (1), was isolated from the culture broth of the marine-derived actinomycete strain CA-271078, together with three known related compounds identified as 4-dehydro-4a-dechloronapyradiomycin A1 (2), napyradiomycin A1 (3) and 3-chloro-6,8-dihydroxy-8-α-lapachone (4). The
[...] Read more.
A new napyradiomycin, MDN-0170 (1), was isolated from the culture broth of the marine-derived actinomycete strain CA-271078, together with three known related compounds identified as 4-dehydro-4a-dechloronapyradiomycin A1 (2), napyradiomycin A1 (3) and 3-chloro-6,8-dihydroxy-8-α-lapachone (4). The structure of the new compound was determined using a combination of spectroscopic techniques, including 1D and 2D NMR and electrospray-time of flight mass spectrometry (ESI-TOF MS). The relative configuration of compound 1, which contains two independent stereoclusters, has been established by molecular modelling in combination with nOe and coupling constant analyses. Biosynthetic arguments also allowed us to propose its absolute stereochemistry. The antimicrobial properties of the compounds isolated were evaluated against methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli, Aspergillus fumigatus, and Candida albicans. The potent bioactivity previously reported for compounds 2 and 3 against methicillin-sensitive S. aureus has been extended to methicillin-resistant strains in this report. Full article
(This article belongs to the Special Issue Marine Organohalides)
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Open AccessArticle Three New Cytotoxic Polyhydroxysteroidal Glycosides from Starfish Craspidaster hesperus
Mar. Drugs 2016, 14(10), 189; doi:10.3390/md14100189
Received: 14 August 2016 / Revised: 9 October 2016 / Accepted: 11 October 2016 / Published: 19 October 2016
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Abstract
Three new polyhydroxysteroidal glycosides, hesperuside A (1), B (2), and C (3), as well as a known novaeguinoside A (4), were isolated from the ethanol extract of starfish Craspidaster hesperus collected from the South China
[...] Read more.
Three new polyhydroxysteroidal glycosides, hesperuside A (1), B (2), and C (3), as well as a known novaeguinoside A (4), were isolated from the ethanol extract of starfish Craspidaster hesperus collected from the South China Sea. Their structures were elucidated by extensive spectroscopic methods and chemical evidence. The compounds 13 present unprecedented carbohydrate chain 3-O-methyl-β-d-galactopyranose, which differ from each other in the side chains. These compounds exhibited cytotoxicity against human tumor cells BEL-7402, MOLT-4, and A-549 in vitro. Full article
(This article belongs to the collection Bioactive Compounds from Marine Invertebrates)
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Open AccessArticle Different Culture Metabolites of the Red Sea Fungus Fusarium equiseti Optimize the Inhibition of Hepatitis C Virus NS3/4A Protease (HCV PR)
Mar. Drugs 2016, 14(10), 190; doi:10.3390/md14100190
Received: 30 August 2016 / Revised: 29 September 2016 / Accepted: 11 October 2016 / Published: 20 October 2016
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Abstract
The endophytic fungus Fusarium equiseti was isolated from the brown alga Padina pavonica, collected from the Red Sea. The fungus was identified by its morphology and 18S rDNA. Cultivation of this fungal strain in biomalt-peptone medium led to isolation of 12 known
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The endophytic fungus Fusarium equiseti was isolated from the brown alga Padina pavonica, collected from the Red Sea. The fungus was identified by its morphology and 18S rDNA. Cultivation of this fungal strain in biomalt-peptone medium led to isolation of 12 known metabolites of diketopeprazines and anthraquinones. The organic extract and isolated compounds were screened for their inhibition of hepatitis C virus NS3/4A protease (HCV PR). As a result, the fungal metabolites showed inhibition of HCV protease (IC50 from 19 to 77 μM), and the fungus was subjected to culture on Czapek’s (Cz) media, with a yield of nine metabolites with potent HCV protease inhibition ranging from IC50 10 to 37 μM. The Cz culture extract exhibited high-level inhibition of HCV protease (IC50 27.6 μg/mL) compared to the biomalt culture extract (IC50 56 μg/mL), and the most potent HCV PR isolated compound (Griseoxanthone C, IC50 19.8 μM) from the bio-malt culture extract showed less of an inhibitory effect compared to isolated ω-hydroxyemodin (IC50 10.7 μM) from the optimized Cz culture extract. Both HCV PR active inhibitors ω-hydroxyemodin and griseoxanthone C were considered as the lowest selective safe constituents against Trypsin inhibitory effect with IC50 48.5 and 51.3 μM, respectively. Full article
(This article belongs to the Special Issue Enzyme Inhibitors of Marine Origin)
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Open AccessArticle Fabrication of Gelatin-Based Electrospun Composite Fibers for Anti-Bacterial Properties and Protein Adsorption
Mar. Drugs 2016, 14(10), 192; doi:10.3390/md14100192
Received: 5 September 2016 / Revised: 14 October 2016 / Accepted: 17 October 2016 / Published: 21 October 2016
Cited by 2 | PDF Full-text (6374 KB) | HTML Full-text | XML Full-text
Abstract
A major goal of biomimetics is the development of chemical compositions and structures that simulate the extracellular matrix. In this study, gelatin-based electrospun composite fibrous membranes were prepared by electrospinning to generate bone scaffold materials. The gelatin-based multicomponent composite fibers were fabricated using
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A major goal of biomimetics is the development of chemical compositions and structures that simulate the extracellular matrix. In this study, gelatin-based electrospun composite fibrous membranes were prepared by electrospinning to generate bone scaffold materials. The gelatin-based multicomponent composite fibers were fabricated using co-electrospinning, and the composite fibers of chitosan (CS), gelatin (Gel), hydroxyapatite (HA), and graphene oxide (GO) were successfully fabricated for multi-function characteristics of biomimetic scaffolds. The effect of component concentration on composite fiber morphology, antibacterial properties, and protein adsorption were investigated. Composite fibers exhibited effective antibacterial activity against Staphylococcus aureus and Escherichia coli. The study observed that the composite fibers have higher adsorption capacities of bovine serum albumin (BSA) at pH 5.32–6.00 than at pH 3.90–4.50 or 7.35. The protein adsorption on the surface of the composite fiber increased as the initial BSA concentration increased. The surface of the composite reached adsorption equilibrium at 20 min. These results have specific applications for the development of bone scaffold materials, and broad implications in the field of tissue engineering. Full article
(This article belongs to the Special Issue Advances in Marine Chitin and Chitosan II, 2017)
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Open AccessCommunication Degree of Suppression of Mouse Myoblast Cell Line C2C12 Differentiation Varies According to Chondroitin Sulfate Subtype
Mar. Drugs 2016, 14(10), 193; doi:10.3390/md14100193
Received: 15 September 2016 / Revised: 12 October 2016 / Accepted: 17 October 2016 / Published: 21 October 2016
Cited by 1 | PDF Full-text (3038 KB) | HTML Full-text | XML Full-text
Abstract
Chondroitin sulfate (CS), a type of glycosaminoglycan (GAG), is a factor involved in the suppression of myogenic differentiation. CS comprises two repeating sugars and has different subtypes depending on the position and number of bonded sulfate groups. However, the effect of each subtype
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Chondroitin sulfate (CS), a type of glycosaminoglycan (GAG), is a factor involved in the suppression of myogenic differentiation. CS comprises two repeating sugars and has different subtypes depending on the position and number of bonded sulfate groups. However, the effect of each subtype on myogenic differentiation remains unclear. In this study, we spiked cultures of C2C12 myoblasts, cells which are capable of undergoing skeletal muscle differentiation, with one of five types of CS (CS-A, -B, -C, -D, or -E) and induced differentiation over a fixed time. After immunostaining of the formed myotubes with an anti-MHC antibody, we counted the number of nuclei in the myotubes and then calculated the fusion index (FI) as a measure of myotube differentiation. The FI values of all the CS-treated groups were lower than the FI value of the control group, especially the group treated with CS-E, which displayed notable suppression of myotube formation. To confirm that the sugar chain in CS-E is important in the suppression of differentiation, chondroitinase ABC (ChABC), which catabolizes CS, was added to the media. The addition of ChABC led to the degradation of CS-E, and neutralized the suppression of myotube formation by CS-E. Collectively, it can be concluded that the degree of suppression of differentiation depends on the subtype of CS and that CS-E strongly suppresses myogenic differentiation. We conclude that the CS sugar chain has inhibitory action against myoblast cell fusion. Full article
(This article belongs to the collection Bioactive Compounds from Marine Invertebrates)
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Open AccessReview Marine Microbiological Enzymes: Studies with Multiple Strategies and Prospects
Mar. Drugs 2016, 14(10), 171; doi:10.3390/md14100171
Received: 12 July 2016 / Revised: 4 September 2016 / Accepted: 14 September 2016 / Published: 22 September 2016
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Abstract
Marine microorganisms produce a series of promising enzymes that have been widely used or are potentially valuable for our daily life. Both classic and newly developed biochemistry technologies have been broadly used to study marine and terrestrial microbiological enzymes. In this brief review,
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Marine microorganisms produce a series of promising enzymes that have been widely used or are potentially valuable for our daily life. Both classic and newly developed biochemistry technologies have been broadly used to study marine and terrestrial microbiological enzymes. In this brief review, we provide a research update and prospects regarding regulatory mechanisms and related strategies of acyl-homoserine lactones (AHL) lactonase, which is an important but largely unexplored enzyme. We also detail the status and catalytic mechanism of the main types of polysaccharide-degrading enzymes that broadly exist among marine microorganisms but have been poorly explored. In order to facilitate understanding, the regulatory and synthetic biology strategies of terrestrial microorganisms are also mentioned in comparison. We anticipate that this review will provide an outline of multiple strategies for promising marine microbial enzymes and open new avenues for the exploration, engineering and application of various enzymes. Full article
(This article belongs to the Special Issue Marine Proteins and Peptides)
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Open AccessReview Residues Responsible for the Selectivity of α-Conotoxins for Ac-AChBP or nAChRs
Mar. Drugs 2016, 14(10), 173; doi:10.3390/md14100173
Received: 28 July 2016 / Revised: 20 September 2016 / Accepted: 21 September 2016 / Published: 11 October 2016
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Abstract
Nicotinic acetylcholine receptors (nAChRs) are targets for developing new drugs to treat severe pain, nicotine addiction, Alzheimer disease, epilepsy, etc. α-Conotoxins are biologically and chemically diverse. With 12–19 residues and two disulfides, they can be specifically selected for different nAChRs. Acetylcholine-binding proteins from
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Nicotinic acetylcholine receptors (nAChRs) are targets for developing new drugs to treat severe pain, nicotine addiction, Alzheimer disease, epilepsy, etc. α-Conotoxins are biologically and chemically diverse. With 12–19 residues and two disulfides, they can be specifically selected for different nAChRs. Acetylcholine-binding proteins from Aplysia californica (Ac-AChBP) are homologous to the ligand-binding domains of nAChRs and pharmacologically similar. X-ray structures of the α-conotoxin in complex with Ac-AChBP in addition to computer modeling have helped to determine the binding site of the important residues of α-conotoxin and its affinity for nAChR subtypes. Here, we present the various α-conotoxin residues that are selective for Ac-AChBP or nAChRs by comparing the structures of α-conotoxins in complex with Ac-AChBP and by modeling α-conotoxins in complex with nAChRs. The knowledge of these binding sites will assist in the discovery and design of more potent and selective α-conotoxins as drug leads. Full article
(This article belongs to the Special Issue Structural Techniques in Natural Products Drug Discovery)
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Open AccessReview Extracellular Metabolites from Industrial Microalgae and Their Biotechnological Potential
Mar. Drugs 2016, 14(10), 191; doi:10.3390/md14100191
Received: 16 August 2016 / Revised: 23 September 2016 / Accepted: 9 October 2016 / Published: 20 October 2016
Cited by 3 | PDF Full-text (271 KB) | HTML Full-text | XML Full-text
Abstract
Industrial microalgae, as a big family of promising producers of renewable biomass feedstock, have been commercially exploited for functional food, living feed and feed additives, high-value chemicals in nutraceuticals, cosmeceuticals, and chemical reagents. Recently, microalgae have also been considered as a group that
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Industrial microalgae, as a big family of promising producers of renewable biomass feedstock, have been commercially exploited for functional food, living feed and feed additives, high-value chemicals in nutraceuticals, cosmeceuticals, and chemical reagents. Recently, microalgae have also been considered as a group that might play an important role in biofuel development and environmental protection. Almost all current products of industrial microalgae are derived from their biomass; however, large amounts of spent cell-free media are available from mass cultivation that is mostly unexploited. In this contribution we discuss that these media, which may contain a remarkable diversity of bioactive substances are worthy to be recovered for further use. Obviously, the extracellular metabolites from industrial microalgae have long been neglected in the development of production methods for valuable metabolites. With the advances in the last ten years, more and more structures and properties from extracellular metabolites have been identified, and the potential utilization over wide fields is attracting attention. Some of these extracellular metabolites can be potentially used as drugs, antioxidants, growth regulators or metal chelators. The purpose of this review is to provide an overview of the known extracellular metabolites from industrial microalgae which might be of commercial interest. The attention mainly focuses on the reports of extracellular bioactive metabolites and their potential application in biotechnology. Full article
(This article belongs to the collection Bioactive Compounds from Marine Plankton)

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