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Mar. Drugs, Volume 8, Issue 5 (May 2010), Pages 1482-1730

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Research

Jump to: Review

Open AccessArticle Biological Activities of Aqueous and Organic Extracts from Tropical Marine Sponges
Mar. Drugs 2010, 8(5), 1550-1566; doi:10.3390/md8051550
Received: 3 March 2010 / Revised: 26 March 2010 / Accepted: 2 April 2010 / Published: 28 April 2010
Cited by 27 | PDF Full-text (366 KB) | HTML Full-text | XML Full-text
Abstract
We report on screening tests of 66 extracts obtained from 35 marine sponge species from the Caribbean Sea (Curaçao) and from eight species from the Great Barrier Reef (Lizard Island). Extracts were prepared in aqueous and organic solvents and were tested for hemolytic,
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We report on screening tests of 66 extracts obtained from 35 marine sponge species from the Caribbean Sea (Curaçao) and from eight species from the Great Barrier Reef (Lizard Island). Extracts were prepared in aqueous and organic solvents and were tested for hemolytic, hemagglutinating, antibacterial and anti-acetylcholinesterase (AChE) activities, as well as their ability to inhibit or activate cell protein phosphatase 1 (PP1). The most interesting activities were obtained from extracts of Ircinia felix, Pandaros acanthifolium, Topsentia ophiraphidites, Verongula rigida and Neofibularia nolitangere. Aqueous and organic extracts of I. felix and V. rigida showed strong antibacterial activity. Topsentia aqueous and some organic extracts were strongly hemolytic, as were all organic extracts from I. felix. The strongest hemolytic activity was observed in aqueous extracts from P. acanthifolium. Organic extracts of N. nolitangere and I. felix inhibited PP1. The aqueous extract from Myrmekioderma styx possessed the strongest hemagglutinating activity, whilst AChE inhibiting activity was found only in a few sponges and was generally weak, except in the methanolic extract of T. ophiraphidites. Full article
(This article belongs to the Special Issue Bioactive Compounds from Marine Sponges)
Open AccessArticle Cloning and Characterization of Glutamate Receptors in Californian Sea Lions (Zalophus californianus)
Mar. Drugs 2010, 8(5), 1637-1649; doi:10.3390/md8051637
Received: 12 March 2010 / Revised: 16 April 2010 / Accepted: 29 April 2010 / Published: 6 May 2010
Cited by 3 | PDF Full-text (238 KB) | HTML Full-text | XML Full-text
Abstract
Domoic acid produced by marine algae has been shown to cause acute and chronic neurologic sequelae in Californian sea lions following acute or low-dose exposure. Histological findings in affected animals included a degenerative cardiomyopathy that was hypothesized to be caused by over-excitation of
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Domoic acid produced by marine algae has been shown to cause acute and chronic neurologic sequelae in Californian sea lions following acute or low-dose exposure. Histological findings in affected animals included a degenerative cardiomyopathy that was hypothesized to be caused by over-excitation of the glutamate receptors (GluRs) speculated to be present in the sea lion heart. Thus tissues from five sea lions without lesions associated with domoic acid toxicity and one animal with domoic acid-induced chronic neurologic sequelae and degenerative cardiomyopathy were examined for the presence of GluRs. Immunohistochemistry localized mGluR 2/3, mGluR 5, GluR 2/3 and NMDAR 1 in structures of the conducting system and blood vessels. NMDAR 1 and GluR 2/3 were the most widespread as immunoreactivity was observed within sea lion conducting system structures. PCR analysis, cloning and subsequent sequencing of the seal lion GluRs showed only 80% homology to those from rats, but more than 95% homologous to those from dogs. The cellular distribution and expression of subtypes of GluRs in the sea lion hearts suggests that exposure to domoic acid may induce cardiac damage and functional disturbances. Full article
Open AccessArticle Combined Effects of UVR and Temperature on the Survival of Crab Larvae (Zoea I) from Patagonia: The Role of UV-Absorbing Compounds
Mar. Drugs 2010, 8(5), 1681-1698; doi:10.3390/md8051681
Received: 22 April 2010 / Revised: 12 May 2010 / Accepted: 21 May 2010 / Published: 25 May 2010
Cited by 14 | PDF Full-text (412 KB) | HTML Full-text | XML Full-text
Abstract
The aim of our study was to assess the combined impact of UVR (280–400 nm) and temperature on the first larval stage (Zoea I) of three crab species from the Patagonian coast: Cyrtograpsus altimanus, C. angulatus,and Leucippa pentagona. We determined
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The aim of our study was to assess the combined impact of UVR (280–400 nm) and temperature on the first larval stage (Zoea I) of three crab species from the Patagonian coast: Cyrtograpsus altimanus, C. angulatus,and Leucippa pentagona. We determined the survival response of newly hatched Zoea I after being exposed for 8–10 h under a solar simulator (Hönle SOL 1200) at 15 and 20 °C. There was no mortality due to Photosynthetic Active Radiation (PAR, 400–700 nm) or ultraviolet-A radiation (UV-A, 315–400 nm), and all the observed mortality was due to ultraviolet-B radiation (UV-B, 280–315 nm). The data of larval mortality relative to exposure time was best fit using a sigmoid curve. Based on this curve, a threshold (Th) and the lethal dose for 50% mortality (LD50) were determined for each species. Based on the Th and LD50, C. altimanus was found to be the most resistant species, while L. pentagona was found to be the most sensitive to UV-B. For both species of Cyrtograpsus, mortality was significantly lower at 20 °C than at 15 °C; however, no significant differences between the two temperature treatments were found in L. pentagona. Bioaccumulation of UV-absorbing compounds in the gonads and larvae of C. altimanus, and to a lesser extent in C. angulatus, might have contributed for counteracting the impact of UV-B. However, most of the resilience to UV-B observed with the increase in temperature might be due to an increase in metabolic activity caused by a repair mechanism mediated by enzymes. Full article
(This article belongs to the Special Issue Marine Photoprotective Compounds)
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Open AccessArticle Evaluation of Three Chitin Metal Silicate Co-Precipitates as a Potential Multifunctional Single Excipient in Tablet Formulations
Mar. Drugs 2010, 8(5), 1699-1715; doi:10.3390/md8051699
Received: 9 March 2010 / Revised: 15 April 2010 / Accepted: 26 April 2010 / Published: 25 May 2010
Cited by 7 | PDF Full-text (168 KB) | HTML Full-text | XML Full-text
Abstract
The performance of the novel chitin metal silicate (CMS) co-precipitates as a single multifunctional excipient in tablet formulation using direct compression and wet granulation methods is evaluated. The neutral, acidic, and basic drugs Spironolactone (SPL), ibuprofen (IBU) and metronidazole (MET), respectively, were used
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The performance of the novel chitin metal silicate (CMS) co-precipitates as a single multifunctional excipient in tablet formulation using direct compression and wet granulation methods is evaluated. The neutral, acidic, and basic drugs Spironolactone (SPL), ibuprofen (IBU) and metronidazole (MET), respectively, were used as model drugs. Commercial Aldactone®, Fleximex® and Dumazole® tablets containing SPL, IBU and MET, respectively, and tablets made using Avicel® 200, were used in the study for comparison purposes. Tablets of acceptable crushing strength (>40 N) were obtained using CMS. The friability values for all tablets were well below the maximum 1% USP tolerance limit. CMS produced superdisintegrating tablets (disintegration time < 1 min) with the three model drugs. Regarding the dissolution rate, the sequence was as follow: CMS > Fleximex® > Avicel® 200, CMS > Avicel® 200 > Dumazole® and Aldactone® > Avicel® 200 > CMS for IBU, MET and SPL, respectively. Compressional properties of formulations were analyzed using density measurements and the compression Kawakita equation as assessment parameters. On the basis of DSC results, CMS co precipitates were found to be compatible with the tested drugs. Conclusively, the CMS co-precipitates have the potential to be used as filler, binder, and superdisintegrant, all-in-one, in the design of tablets by the direct compression as well as wet granulation methods. Full article
(This article belongs to the Special Issue Marine Chitin and Chitosan)
Open AccessArticle Bioadhesive Controlled Metronidazole Release Matrix Based on Chitosan and Xanthan Gum
Mar. Drugs 2010, 8(5), 1716-1730; doi:10.3390/md8051716
Received: 9 March 2010 / Revised: 23 March 2010 / Accepted: 6 April 2010 / Published: 25 May 2010
Cited by 17 | PDF Full-text (205 KB) | HTML Full-text | XML Full-text
Abstract
Metronidazole, a common antibacterial drug, was incorporated into a hydrophilic polymer matrix composed of chitosan xanthan gum mixture. Hydrogel formation of this binary chitosan-xanthan gum combination was tested for its ability to control the release of metronidazole as a drug model. This preparation
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Metronidazole, a common antibacterial drug, was incorporated into a hydrophilic polymer matrix composed of chitosan xanthan gum mixture. Hydrogel formation of this binary chitosan-xanthan gum combination was tested for its ability to control the release of metronidazole as a drug model. This preparation (MZ-CR) was characterized by in vitro, ex vivo bioadhesion and in vivo bioavailability study. For comparison purposes a commercial extended release formulation of metronidazole (CMZ) was used as a reference. The in vitro drug-release profiles of metronidazole preparation and CMZ were similar in 0.1 M HCl and phosphate buffer pH 6.8. Moreover, metronidazole preparation and CMZ showed a similar detachment force to sheep stomach mucosa, while the bioadhesion of the metronidazole preparation was higher three times than CMZ to sheep duodenum. The results of in vivo study indicated that the absorption of metronidazole from the preparation was faster than that of CMZ. Also, MZ-CR leads to higher metronidazole Cmax and AUC relative to that of the CMZ. This increase in bioavailability might be explained by the bioadhesion of the preparation at the upper part of the small intestine that could result in an increase in the overall intestinal transit time. As a conclusion, formulating chitosan-xanthan gum mixture as a hydrophilic polymer matrix resulted in a superior pharmacokinetic parameters translated by better rate and extent of absorption of metronidazole. Full article
(This article belongs to the Special Issue Marine Chitin and Chitosan)

Review

Jump to: Research

Open AccessReview Production of Chitooligosaccharides and Their Potential Applications in Medicine
Mar. Drugs 2010, 8(5), 1482-1517; doi:10.3390/md8051482
Received: 5 March 2010 / Revised: 14 April 2010 / Accepted: 23 April 2010 / Published: 27 April 2010
Cited by 161 | PDF Full-text (1047 KB) | HTML Full-text | XML Full-text
Abstract
Chitooligosaccharides (CHOS) are homo- or heterooligomers of N-acetylglucosamine and D-glucosamine. CHOS can be produced using chitin or chitosan as a starting material, using enzymatic conversions, chemical methods or combinations thereof. Production of well-defined CHOS-mixtures, or even pure CHOS, is of great
[...] Read more.
Chitooligosaccharides (CHOS) are homo- or heterooligomers of N-acetylglucosamine and D-glucosamine. CHOS can be produced using chitin or chitosan as a starting material, using enzymatic conversions, chemical methods or combinations thereof. Production of well-defined CHOS-mixtures, or even pure CHOS, is of great interest since these oligosaccharides are thought to have several interesting bioactivities. Understanding the mechanisms underlying these bioactivities is of major importance. However, so far in-depth knowledge on the mode-of-action of CHOS is scarce, one major reason being that most published studies are done with badly characterized heterogeneous mixtures of CHOS. Production of CHOS that are well-defined in terms of length, degree of N-acetylation, and sequence is not straightforward. Here we provide an overview of techniques that may be used to produce and characterize reasonably well-defined CHOS fractions. We also present possible medical applications of CHOS, including tumor growth inhibition and inhibition of TH2-induced inflammation in asthma, as well as use as a bone-strengthener in osteoporosis, a vector for gene delivery, an antibacterial agent, an antifungal agent, an anti-malaria agent, or a hemostatic agent in wound-dressings. By using well-defined CHOS-mixtures it will become possible to obtain a better understanding of the mechanisms underlying these bioactivities. Full article
(This article belongs to the Special Issue Marine Chitin and Chitosan)
Open AccessReview Chitin and Chitosan as Multipurpose Natural Polymers for Groundwater Arsenic Removal and As2O3 Delivery in Tumor Therapy
Mar. Drugs 2010, 8(5), 1518-1525; doi:10.3390/md8051518
Received: 27 March 2010 / Revised: 23 April 2010 / Accepted: 26 April 2010 / Published: 28 April 2010
Cited by 19 | PDF Full-text (137 KB) | HTML Full-text | XML Full-text
Abstract
Chitin and chitosan are natural polysaccharide polymers. These polymers have been used in several agricultural, food protection and nutraceutical applications. Moreover, chitin and chitosan have been also used in biomedical and biotechnological applications as drug delivery systems or in pharmaceutical formulations. So far,
[...] Read more.
Chitin and chitosan are natural polysaccharide polymers. These polymers have been used in several agricultural, food protection and nutraceutical applications. Moreover, chitin and chitosan have been also used in biomedical and biotechnological applications as drug delivery systems or in pharmaceutical formulations. So far, there are only few studies dealing with arsenic (As) removal from groundwater using chitin or chitosan and no evidence of the use of these natural polymers for arsenic trioxide (As2O3) delivery in tumor therapy. Here we suggest that chitin and/or chitosan might have the right properties to be employed as efficient polymers for such applications. Besides, nanotechnology offers suitable tools for the fabrication of novel nanostructured materials of natural origin. Since different nanostructured materials have already been employed successfully in various multidisciplinary fields, we expect that the integration of nanotechnology and natural polymer chemistry will further lead to innovative applications for environment and medicine. Full article
(This article belongs to the Special Issue Marine Chitin and Chitosan)
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Open AccessReview Halogenated Indole Alkaloids from Marine Invertebrates
Mar. Drugs 2010, 8(5), 1526-1549; doi:10.3390/md8051526
Received: 2 March 2010 / Revised: 19 April 2010 / Accepted: 23 April 2010 / Published: 28 April 2010
Cited by 39 | PDF Full-text (349 KB) | HTML Full-text | XML Full-text
Abstract
This review discusses the isolation, structural elucidation, and biological activities of halogenated indole alkaloids obtained from marine invertebrates. Meridianins and related compounds (variolins, psammopemmins, and aplicyanins), as well as aplysinopsins and leptoclinidamines, are focused on. A compilation of the 13C-NMR spectral data
[...] Read more.
This review discusses the isolation, structural elucidation, and biological activities of halogenated indole alkaloids obtained from marine invertebrates. Meridianins and related compounds (variolins, psammopemmins, and aplicyanins), as well as aplysinopsins and leptoclinidamines, are focused on. A compilation of the 13C-NMR spectral data of these selected natural indole alkaloids is also provided. Full article
(This article belongs to the Special Issue Bioactive Halogenated Metabolites of Marine Origin)
Open AccessReview Application of Spectroscopic Methods for Structural Analysis of Chitin and Chitosan
Mar. Drugs 2010, 8(5), 1567-1636; doi:10.3390/md8051567
Received: 8 March 2010 / Revised: 30 March 2010 / Accepted: 27 April 2010 / Published: 29 April 2010
Cited by 179 | PDF Full-text (1140 KB) | HTML Full-text | XML Full-text
Abstract
Chitin, the second most important natural polymer in the world, and its N-deacetylated derivative chitosan, have been identified as versatile biopolymers for a broad range of applications in medicine, agriculture and the food industry. Two of the main reasons for this are
[...] Read more.
Chitin, the second most important natural polymer in the world, and its N-deacetylated derivative chitosan, have been identified as versatile biopolymers for a broad range of applications in medicine, agriculture and the food industry. Two of the main reasons for this are firstly the unique chemical, physicochemical and biological properties of chitin and chitosan, and secondly the unlimited supply of raw materials for their production. These polymers exhibit widely differing physicochemical properties depending on the chitin source and the conditions of chitosan production. The presence of reactive functional groups as well as the polysaccharide nature of these biopolymers enables them to undergo diverse chemical modifications. A complete chemical and physicochemical characterization of chitin, chitosan and their derivatives is not possible without using spectroscopic techniques. This review focuses on the application of spectroscopic methods for the structural analysis of these compounds. Full article
(This article belongs to the Special Issue Marine Chitin and Chitosan)
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Open AccessReview On the Chemistry, Toxicology and Genetics of the Cyanobacterial Toxins, Microcystin, Nodularin, Saxitoxin and Cylindrospermopsin
Mar. Drugs 2010, 8(5), 1650-1680; doi:10.3390/md8051650
Received: 26 March 2010 / Revised: 2 May 2010 / Accepted: 6 May 2010 / Published: 10 May 2010
Cited by 192 | PDF Full-text (684 KB) | HTML Full-text | XML Full-text
Abstract
The cyanobacteria or “blue-green algae”, as they are commonly termed, comprise a diverse group of oxygenic photosynthetic bacteria that inhabit a wide range of aquatic and terrestrial environments, and display incredible morphological diversity. Many aquatic, bloom-forming species of cyanobacteria are capable of producing
[...] Read more.
The cyanobacteria or “blue-green algae”, as they are commonly termed, comprise a diverse group of oxygenic photosynthetic bacteria that inhabit a wide range of aquatic and terrestrial environments, and display incredible morphological diversity. Many aquatic, bloom-forming species of cyanobacteria are capable of producing biologically active secondary metabolites, which are highly toxic to humans and other animals. From a toxicological viewpoint, the cyanotoxins span four major classes: the neurotoxins, hepatotoxins, cytotoxins, and dermatoxins (irritant toxins). However, structurally they are quite diverse. Over the past decade, the biosynthesis pathways of the four major cyanotoxins: microcystin, nodularin, saxitoxin and cylindrospermopsin, have been genetically and biochemically elucidated. This review provides an overview of these biosynthesis pathways and additionally summarizes the chemistry and toxicology of these remarkable secondary metabolites. Full article
(This article belongs to the Special Issue Algal Toxins)

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