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Marine Drugs
Volume 15
Issue 12
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Mar. Drugs, Volume 15, Issue 12 (December 2017) – 30 articles

Cover Story (view full-size image): Shown on the cover is a photograph of a bloom of Microcystis sp. in a water reservoir and a close-up of the bloom material with a handful of biologically active metabolites which are produced by cyanobacteria in such blooms. Worldwide studies on the chemistry and toxicology of Microcystis and other cyanobacteria water-blooms, over the last forty-five years, resulted in the discovery of several groups of toxins, of which the microcystins-group is the most abundant and divers with over hundred members. The five groups of protease inhibitors that accompany the microcystins; micropeptins, aeruginosins, anabaenopeptins, microginins and microviridins, sum to more then three hundred and fifty structures. Some other hundred compounds, mainly cyclic peptides, were also described from fresh water cyanobacteria. The stimuli for the biosynthesis of these libraries of compounds is yet hardly understood. View this [...] Read more.
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4789 KiB  
Review
Biotechnological and Pharmacological Applications of Biotoxins and Other Bioactive Molecules from Dinoflagellates
by Joana Assunção, A. Catarina Guedes and F. Xavier Malcata
Mar. Drugs 2017, 15(12), 393; https://doi.org/10.3390/md15120393 - 20 Dec 2017
Cited by 80 | Viewed by 9340
Abstract
The long-lasting interest in bioactive molecules (namely toxins) produced by (microalga) dinoflagellates has risen in recent years. Exhibiting wide diversity and complexity, said compounds are well-recognized for their biological features, with great potential for use as pharmaceutical therapies and biological research probes. Unfortunately, [...] Read more.
The long-lasting interest in bioactive molecules (namely toxins) produced by (microalga) dinoflagellates has risen in recent years. Exhibiting wide diversity and complexity, said compounds are well-recognized for their biological features, with great potential for use as pharmaceutical therapies and biological research probes. Unfortunately, provision of those compounds is still far from sufficient, especially in view of an increasing demand for preclinical testing. Despite the difficulties to establish dinoflagellate cultures and obtain reasonable productivities of such compounds, intensive research has permitted a number of advances in the field. This paper accordingly reviews the characteristics of some of the most important biotoxins (and other bioactive substances) produced by dinoflagellates. It also presents and discusses (to some length) the main advances pertaining to dinoflagellate production, from bench to large scale—with an emphasis on material published since the latest review available on the subject. Such advances encompass improvements in nutrient formulation and light supply as major operational conditions; they have permitted adaptation of classical designs, and aided the development of novel configurations for dinoflagellate growth—even though shearing-related issues remain a major challenge. Full article
(This article belongs to the Special Issue Marine Microalgae)
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1376 KiB  
Article
Liposomal Circular Dichroism (L-CD) of Arenoyl Derivatives of Sphingolipids. Amplification of Cotton Effects in Ordered Lipid Bilayers
by Tadeusz F. Molinski, Caroline D. Broaddus and Brandon I. Morinaka
Mar. Drugs 2017, 15(12), 352; https://doi.org/10.3390/md15120352 - 20 Dec 2017
Cited by 1 | Viewed by 5179
Abstract
Liposomal circular dichroism (L-CD) of acyclic amino alcohols exhibit amplification of Cotton effects when measured in highly uniform, unilamellar liposomes. The effect is likely due to intermolecular associations—H-aggregates—that self-assemble spontaneously within the lipid bilayer, and persists over long time scales. L-CD spectra of [...] Read more.
Liposomal circular dichroism (L-CD) of acyclic amino alcohols exhibit amplification of Cotton effects when measured in highly uniform, unilamellar liposomes. The effect is likely due to intermolecular associations—H-aggregates—that self-assemble spontaneously within the lipid bilayer, and persists over long time scales. L-CD spectra of N,O,O′-tri-(6′methoxy-2′-naphthoyl)-d-erythro-sphingosine, or the corresponding dihydro-derivative (sphinganine), shows ~10-fold amplification of magnitudes of Cotton effects over conventional CD spectra recorded in isotropic solution. Full article
(This article belongs to the Special Issue Structural Techniques in Natural Products Drug Discovery)
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1272 KiB  
Article
New Cytotoxic Terpenoids from Soft Corals Nephthea chabroli and Paralemnalia thyrsoides
by Yu-Sheng Lee, Tsai-Hui Duh, Shu-Sheng Siao, Rey-Chang Chang, Shang-Kwei Wang and Chang-Yih Duh
Mar. Drugs 2017, 15(12), 392; https://doi.org/10.3390/md15120392 - 19 Dec 2017
Cited by 18 | Viewed by 5069
Abstract
A novel cytotoxic diterpenoid, chabrolin A (1) (possessing an unprecedented terpenoid skeleton), as well as three new cytotoxic sesquiterpenoids, parathyrsoidins E–G (2–4), were isolated by cytotoxicity-guided fractionation from soft corals Nephthea chabroli and Paralemnalia thyrsoides. The [...] Read more.
A novel cytotoxic diterpenoid, chabrolin A (1) (possessing an unprecedented terpenoid skeleton), as well as three new cytotoxic sesquiterpenoids, parathyrsoidins E–G (2–4), were isolated by cytotoxicity-guided fractionation from soft corals Nephthea chabroli and Paralemnalia thyrsoides. The structures of the new compounds were determined by extensive analysis of spectroscopic data. Full article
(This article belongs to the Special Issue Natural Products from Coral Reef Organisms)
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Article
LC-MS/MS Detection of Karlotoxins Reveals New Variants in Strains of the Marine Dinoflagellate Karlodinium veneficum from the Ebro Delta (NW Mediterranean)
by Bernd Krock, Julia A. Busch, Urban Tillmann, Francisco García-Camacho, Asterio Sánchez-Mirón, Juan J. Gallardo-Rodríguez, Lorenzo López-Rosales, Karl B. Andree, Margarita Fernández-Tejedor, Matthias Witt, Allan D. Cembella and Allen R. Place
Mar. Drugs 2017, 15(12), 391; https://doi.org/10.3390/md15120391 - 18 Dec 2017
Cited by 21 | Viewed by 7142
Abstract
A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the detection and quantitation of karlotoxins in the selected reaction monitoring (SRM) mode. This novel method was based upon the analysis of purified karlotoxins (KcTx-1, KmTx-2, 44-oxo-KmTx-2, KmTx-5), one amphidinol (AM-18), and unpurified [...] Read more.
A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the detection and quantitation of karlotoxins in the selected reaction monitoring (SRM) mode. This novel method was based upon the analysis of purified karlotoxins (KcTx-1, KmTx-2, 44-oxo-KmTx-2, KmTx-5), one amphidinol (AM-18), and unpurified extracts of bulk cultures of the marine dinoflagellate Karlodinium veneficum strain CCMP2936 from Delaware (Eastern USA), which produces KmTx-1 and KmTx-3. The limit of detection of the SRM method for KmTx-2 was determined as 2.5 ng on-column. Collision induced dissociation (CID) spectra of all putative karlotoxins were recorded to present fragmentation patterns of each compound for their unambiguous identification. Bulk cultures of K. veneficum strain K10 isolated from an embayment of the Ebro Delta, NW Mediterranean, yielded five previously unreported putative karlotoxins with molecular masses 1280, 1298, 1332, 1356, and 1400 Da, and similar fragments to KmTx-5. Analysis of several isolates of K. veneficum from the Ebro Delta revealed small-scale diversity in the karlotoxin spectrum in that one isolate from Fangar Bay produced KmTx-5, whereas the five putative novel karlotoxins were found among several isolates from nearby, but hydrographically distinct Alfacs Bay. Application of this LC-MS/MS method represents an incremental advance in the determination of putative karlotoxins, particularly in the absence of a complete spectrum of purified analytical standards of known specific potency. Full article
(This article belongs to the Collection Bioactive Compounds from Marine Plankton)
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Article
A Carbon Dioxide Limitation-Inducible Protein, ColA, Supports the Growth of Synechococcus sp. PCC 7002
by Ginga Shimakawa, Satoru Watanabe and Chikahiro Miyake
Mar. Drugs 2017, 15(12), 390; https://doi.org/10.3390/md15120390 - 15 Dec 2017
Cited by 3 | Viewed by 4258
Abstract
A limitation in carbon dioxide (CO2), which occurs as a result of natural environmental variation, suppresses photosynthesis and has the potential to cause photo-oxidative damage to photosynthetic cells. Oxygenic phototrophs have strategies to alleviate photo-oxidative damage to allow life in present [...] Read more.
A limitation in carbon dioxide (CO2), which occurs as a result of natural environmental variation, suppresses photosynthesis and has the potential to cause photo-oxidative damage to photosynthetic cells. Oxygenic phototrophs have strategies to alleviate photo-oxidative damage to allow life in present atmospheric CO2 conditions. However, the mechanisms for CO2 limitation acclimation are diverse among the various oxygenic phototrophs, and many mechanisms remain to be discovered. In this study, we found that the gene encoding a CO2 limitation-inducible protein, ColA, is required for the cyanobacterium Synechococcus sp. PCC 7002 (S. 7002) to acclimate to limited CO2 conditions. An S. 7002 mutant deficient in ColA (ΔcolA) showed lower chlorophyll content, based on the amount of nitrogen, than that in S. 7002 wild-type (WT) under ambient air but not high CO2 conditions. Both thermoluminescence and protein carbonylation detected in the ambient air grown cells indicated that the lack of ColA promotes oxidative stress in S. 7002. Alterations in the photosynthetic O2 evolution rate and relative electron transport rate in the short-term response, within an hour, to CO2 limitation were the same between the WT and ΔcolA. Conversely, these photosynthetic parameters were mostly lower in the long-term response of a few days in ΔcolA than in the WT. These data suggest that ColA is required to sustain photosynthetic activity for living under ambient air in S. 7002. The unique phylogeny of ColA revealed diverse strategies to acclimate to CO2 limitation among cyanobacteria. Full article
(This article belongs to the Special Issue Marine Microalgae)
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Article
α-Pyrone Polyketides from Streptomyces ambofaciens BI0048, an Endophytic Actinobacterial Strain Isolated from the Red Alga Laurencia glandulifera
by Enikő Rab, Dimitrios Kekos, Vassilios Roussis and Efstathia Ioannou
Mar. Drugs 2017, 15(12), 389; https://doi.org/10.3390/md15120389 - 14 Dec 2017
Cited by 15 | Viewed by 4543
Abstract
Four new (1–4) and six previously reported (5–10) α-pyrone polyketides, along with benzoic acid, hydrocinnamic acid, and (E)-cinnamic acid, were isolated from the organic extract resulting from the cultivation of the algicolous strain [...] Read more.
Four new (1–4) and six previously reported (5–10) α-pyrone polyketides, along with benzoic acid, hydrocinnamic acid, and (E)-cinnamic acid, were isolated from the organic extract resulting from the cultivation of the algicolous strain Streptomyces ambofaciens BI0048, which in turn was isolated from the inner tissues of the red alga Laurencia glandulifera. The structure elucidation of the isolated natural products was based on extensive analysis of their spectroscopic data (NMR, MS, UV, IR). Compounds 1–10 were evaluated for their antibacterial and cytotoxic activities against two multidrug-resistant strains of Staphylococcus aureus and one strain of Escherichia coli, as well as two human cancer cell lines. Full article
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6396 KiB  
Review
Recent Advances in Marine Algae Polysaccharides: Isolation, Structure, and Activities
by Shu-Ying Xu, Xuesong Huang and Kit-Leong Cheong
Mar. Drugs 2017, 15(12), 388; https://doi.org/10.3390/md15120388 - 13 Dec 2017
Cited by 317 | Viewed by 21961
Abstract
Marine algae have attracted a great deal of interest as excellent sources of nutrients. Polysaccharides are the main components in marine algae, hence a great deal of attention has been directed at isolation and characterization of marine algae polysaccharides because of their numerous [...] Read more.
Marine algae have attracted a great deal of interest as excellent sources of nutrients. Polysaccharides are the main components in marine algae, hence a great deal of attention has been directed at isolation and characterization of marine algae polysaccharides because of their numerous health benefits. In this review, extraction and purification approaches and chemico-physical properties of marine algae polysaccharides (MAPs) are summarized. The biological activities, which include immunomodulatory, antitumor, antiviral, antioxidant, and hypolipidemic, are also discussed. Additionally, structure-function relationships are analyzed and summarized. MAPs’ biological activities are closely correlated with their monosaccharide composition, molecular weights, linkage types, and chain conformation. In order to promote further exploitation and utilization of polysaccharides from marine algae for functional food and pharmaceutical areas, high efficiency, and low-cost polysaccharide extraction and purification methods, quality control, structure-function activity relationships, and specific mechanisms of MAPs activation need to be extensively investigated. Full article
(This article belongs to the Special Issue Marine Oligosaccharides and Polysaccharides)
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Communication
Collismycin C from the Micronesian Marine Bacterium Streptomyces sp. MC025 Inhibits Staphylococcus aureus Biofilm Formation
by Jin-Hyung Lee, Eonmi Kim, Hyukjae Choi and Jintae Lee
Mar. Drugs 2017, 15(12), 387; https://doi.org/10.3390/md15120387 - 12 Dec 2017
Cited by 24 | Viewed by 4721
Abstract
Biofilm formation plays a critical role in antimicrobial resistance in Staphylococcus aureus. Here, we investigated the potential of crude extracts of 79 Micronesian marine microorganisms to inhibit S. aureus biofilm formation. An extract of Streptomyces sp. MC025 inhibited S. aureus biofilm formation. [...] Read more.
Biofilm formation plays a critical role in antimicrobial resistance in Staphylococcus aureus. Here, we investigated the potential of crude extracts of 79 Micronesian marine microorganisms to inhibit S. aureus biofilm formation. An extract of Streptomyces sp. MC025 inhibited S. aureus biofilm formation. Bioactivity-guided isolation led to the isolation of a series of 2,2′-bipyridines: collismycin B (1), collismycin C (2), SF2738 D (3), SF2738 F (4), pyrisulfoxin A (5), and pyrisulfoxin B (6). Among these bipyridines, collismycin C (2) was found to be the most effective inhibitor of biofilm formation by methicillin-sensitive S. aureus and methicillin-resistant S. aureus (MRSA), and this compound inhibited MRSA biofilm formation by more than 90% at a concentration of 50 μg/mL. The antibiofilm activity of collismycin C was speculated to be related to iron acquisition and the presence and position of the hydroxyl group of 2,2′-bipyridines. Full article
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3022 KiB  
Article
Deep Sea Water Improves Abnormalities in Lipid Metabolism through Lipolysis and Fatty Acid Oxidation in High-Fat Diet-Induced Obese Rats
by Wei-Tang Chang, Tsung-Yueh Lu, Ming-Ching Cheng, Hsun-Chi Lu, Mei-Fang Wu and Chin-Lin Hsu
Mar. Drugs 2017, 15(12), 386; https://doi.org/10.3390/md15120386 - 11 Dec 2017
Cited by 12 | Viewed by 5131
Abstract
Deep sea water (DSW) is a natural marine resource that has been utilized for food, agriculture, cosmetics, and medicine. The aim of this study was to investigate whether DSW has beneficial lipid metabolic effects in an animal model. Our previous in vitro study [...] Read more.
Deep sea water (DSW) is a natural marine resource that has been utilized for food, agriculture, cosmetics, and medicine. The aim of this study was to investigate whether DSW has beneficial lipid metabolic effects in an animal model. Our previous in vitro study indicated that DSW significantly decreased the intracellular triglyceride and glycerol-3-phosphate dehydrogenase activity in 3T3-L1 adipocytes. DSW also inhibited the gene levels of adipocyte differentiation, lipogenesis, and adipocytokines, and up-regulated gene levels of lipolysis and fatty acid oxidation. In the present study, the results showed that body weight, liver, adipose tissue, hepatic triglycerides and cholesterol, and serum parameters in the high-fat diet (HFD) + DSW groups were significantly lower compared to the HFD group. Moreover, the fecal output of total lipids, triglycerides, and cholesterol in the HFD + DSW groups was significantly higher than that of the HFD group. Regarding gene expression, DSW significantly increased the gene levels of lipolysis and fatty acid oxidation, and decreased the gene levels of adipocytokine in the adipose tissue of rats with HFD-induced obesity. These results indicate a potential molecular mechanism by which DSW can suppress obesity in rats with HFD-induced obesity through lipolysis and fatty acid oxidation. Full article
(This article belongs to the Collection Marine Drugs in the Management of Metabolic Diseases)
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5875 KiB  
Article
The Cladophora glomerata Enriched by Biosorption Process in Cr(III) Improves Viability, and Reduces Oxidative Stress and Apoptosis in Equine Metabolic Syndrome Derived Adipose Mesenchymal Stromal Stem Cells (ASCs) and Their Extracellular Vesicles (MV’s)
by Krzysztof Marycz, Izabela Michalak, Ievgeniia Kocherova, Monika Marędziak and Christine Weiss
Mar. Drugs 2017, 15(12), 385; https://doi.org/10.3390/md15120385 - 8 Dec 2017
Cited by 36 | Viewed by 6403
Abstract
This study investigated in vitro effects of freshwater alga Cladophora glomerata water extract enriched during a biosorption process in Cr(III) trivalent chromium and chromium picolinate on adipose-derived mesenchymal stromal stem cells (ASCs) and extracellular microvesicles (MVs) in equine metabolic syndrome-affected horses. Chemical characterisation [...] Read more.
This study investigated in vitro effects of freshwater alga Cladophora glomerata water extract enriched during a biosorption process in Cr(III) trivalent chromium and chromium picolinate on adipose-derived mesenchymal stromal stem cells (ASCs) and extracellular microvesicles (MVs) in equine metabolic syndrome-affected horses. Chemical characterisation of natural Cladophora glomerata was performed with special emphasis on: vitamin C, vitamin E, total phenols, fatty acids, free and protein-bound amino acids as well as measured Cr in algal biomass. To examine the influence of Cladophora glomerata water extracts, in vitro viability, oxidative stress factor accumulation, apoptosis, inflammatory response, biogenesis of mitochondria, autophagy in ASCs of EMS and secretory activity manifested by MV release were investigated. For this purpose, various methods of molecular biology and microscopic observations (i.e., immunofluorescence staining, SEM, TEM, FIB observations, mRNA and microRNA expression by RT-qPCR) were applied. The extract of Cladophora glomerata enriched with Cr(III) ions reduced apoptosis and inflammation in ASCs of EMS horses through improvement of mitochondrial dynamics, decreasing of PDK4 expression and reduction of endoplastic reticulum stress. Moreover, it was found, that Cladophora glomerata and Cr(III) induce antioxidative protection coming from enhanced SOD activity Therefore, Cladophora glomerata enriched with Cr(III) ions might become an interesting future therapeutic agent in the pharmacological treatment of EMS horses. Full article
(This article belongs to the Special Issue Marine Compounds Used in Biosorption)
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2752 KiB  
Review
The Potential of Indonesian Heterobranchs Found around Bunaken Island for the Production of Bioactive Compounds
by Katja M. Fisch, Cora Hertzer, Nils Böhringer, Zerlina G. Wuisan, Dorothee Schillo, Robert Bara, Fontje Kaligis, Heike Wägele, Gabriele M. König and Till F. Schäberle
Mar. Drugs 2017, 15(12), 384; https://doi.org/10.3390/md15120384 - 7 Dec 2017
Cited by 23 | Viewed by 7331
Abstract
The species diversity of marine heterobranch sea slugs found on field trips around Bunaken Island (North Sulawesi, Indonesia) and adjacent islands of the Bunaken National Marine Park forms the basis of this review. In a survey performed in 2015, 80 species from 23 [...] Read more.
The species diversity of marine heterobranch sea slugs found on field trips around Bunaken Island (North Sulawesi, Indonesia) and adjacent islands of the Bunaken National Marine Park forms the basis of this review. In a survey performed in 2015, 80 species from 23 families were collected, including 17 new species. Only three of these have been investigated previously in studies from Indonesia. Combining species diversity with a former study from 2003 reveals in total 140 species from this locality. The diversity of bioactive compounds known and yet to be discovered from these organisms is summarized and related to the producer if known or suspected (might it be down the food chain, de novo synthesised from the slug or an associated bacterium). Additionally, the collection of microorganisms for the discovery of natural products of pharmacological interest from this hotspot of biodiversity that is presented here contains more than 50 species that have never been investigated before in regard to bioactive secondary metabolites. This highlights the great potential of the sea slugs and the associated microorganisms for the discovery of natural products of pharmacological interest from this hotspot of biodiversity. Full article
(This article belongs to the Collection Bioactive Compounds from Marine Invertebrates)
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Article
Isolation of Petrocidin A, a New Cytotoxic Cyclic Dipeptide from the Marine Sponge-Derived Bacterium Streptomyces sp. SBT348
by Cheng Cheng, Eman M. Othman, Helga Stopper, RuAngelie Edrada-Ebel, Ute Hentschel and Usama Ramadan Abdelmohsen
Mar. Drugs 2017, 15(12), 383; https://doi.org/10.3390/md15120383 - 6 Dec 2017
Cited by 31 | Viewed by 6564
Abstract
A new cyclic dipeptide, petrocidin A (1), along with three known compounds—2,3-dihydroxybenzoic acid (2), 2,3-dihydroxybenzamide (3), and maltol (4)—were isolated from the solid culture of Streptomyces sp. SBT348. The strain Streptomyces sp. SBT348 had been [...] Read more.
A new cyclic dipeptide, petrocidin A (1), along with three known compounds—2,3-dihydroxybenzoic acid (2), 2,3-dihydroxybenzamide (3), and maltol (4)—were isolated from the solid culture of Streptomyces sp. SBT348. The strain Streptomyces sp. SBT348 had been prioritized in a strain collection of 64 sponge-associated actinomycetes based on its distinct metabolomic profile using liquid chromatography/high-resolution mass spectrometry (LC-HRMS) and nuclear magnetic resonance (NMR). The absolute configuration of all α-amino acids was determined by HPLC analysis after derivatization with Marfey’s reagent and comparison with commercially available reference amino acids. Structure elucidation was pursued in the presented study by mass spectrometry and NMR spectral data. Petrocidin A (1) and 2,3-dihydroxybenzamide (3) exhibited significant cytotoxicity towards the human promyelocytic HL-60 and the human colon adenocarcinoma HT-29 cell lines. These results demonstrated the potential of sponge-associated actinomycetes for the discovery of novel and pharmacologically active natural products. Full article
(This article belongs to the Special Issue Bioprospecting of Marine Microorganisms)
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Article
Metabolites with Insecticidal Activity from Aspergillus fumigatus JRJ111048 Isolated from Mangrove Plant Acrostichum specioum Endemic to Hainan Island
by Zhikai Guo, Cuijuan Gai, Caihong Cai, Liangliang Chen, Shoubai Liu, Yanbo Zeng, Jingzhe Yuan, Wenli Mei and Haofu Dai
Mar. Drugs 2017, 15(12), 381; https://doi.org/10.3390/md15120381 - 6 Dec 2017
Cited by 38 | Viewed by 4786
Abstract
Fungi residing in mangroves are considered to be a bank of novel bioactive natural products. In the screening for bioactive metabolites from mangrove-derived fungi, the ethyl acetate extract of the fermentation broth of Aspergillus fumigatus JRJ111048, a fungus isolated from the leaves of [...] Read more.
Fungi residing in mangroves are considered to be a bank of novel bioactive natural products. In the screening for bioactive metabolites from mangrove-derived fungi, the ethyl acetate extract of the fermentation broth of Aspergillus fumigatus JRJ111048, a fungus isolated from the leaves of the mangrove plant Acrostichum specioum endemic to Hainan island, was found to possess insecticidal activity against Spodoptera litura. Bioactivity-guided isolation lead to the discovery of seven metabolites 1–7, including one new anhydride derivative aspergide (1), one new lipid amide 11-methyl-11-hydroxyldodecanoic acid amide (2), and five known compounds; α-ethyl glucoside (3), spiculisporic acid B (4), spiculisporic acid C (5), spiculisporic acid (6), and secospiculisporic acid B (7). Their structures were established by NMR spectroscopic and MS analyses, and by comparison of previously reported data. Insecticidal activity against S. litura and antifungal activity of these compounds were investigated. As a result, the new compound 1 showed potent insecticidal activity against newly hatched larvae of S. litura, and compound 4 displayed weak antifungal activity against Candida albicans. Full article
(This article belongs to the Collection Papers from “Sino–Italian Symposium on Bioactive Natural Products”)
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Review
Terpenoids from Octocorals of the Genus Pachyclavularia
by Yu-Chia Chang, Jyh-Horng Sheu, Yang-Chang Wu and Ping-Jyun Sung
Mar. Drugs 2017, 15(12), 382; https://doi.org/10.3390/md15120382 - 5 Dec 2017
Cited by 12 | Viewed by 4351
Abstract
In this paper, we reviewed natural compounds isolated from octocorals belonging to the genus Pachyclavularia, including 20 cembrane-, 39 briarane-, and eight briarellin-related diterpenoids, and one secosterol. The chemical constituents of these 68 secondary metabolites, and their names, structures, and bioactivities, along [...] Read more.
In this paper, we reviewed natural compounds isolated from octocorals belonging to the genus Pachyclavularia, including 20 cembrane-, 39 briarane-, and eight briarellin-related diterpenoids, and one secosterol. The chemical constituents of these 68 secondary metabolites, and their names, structures, and bioactivities, along with studies of their biological activities, are summarized in this review. Based on the literature, many of these compounds possess bioactivities, including anti-inflammation properties, cytotoxicity, and ichthyotoxicity, suggesting that they may have the potential to be developed into biomedical agents for treatment. Full article
(This article belongs to the Special Issue Development and Application of Herbal Medicine from Marine Origin)
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Article
Bioinspiring Chondrosia reniformis (Nardo, 1847) Collagen-Based Hydrogel: A New Extraction Method to Obtain a Sticky and Self-Healing Collagenous Material
by Dario Fassini, Ana Rita C. Duarte, Rui L. Reis and Tiago H. Silva
Mar. Drugs 2017, 15(12), 380; https://doi.org/10.3390/md15120380 - 4 Dec 2017
Cited by 19 | Viewed by 6406
Abstract
Collagen is a natural and abundant polymer that serves multiple functions in both invertebrates and vertebrates. As collagen is the natural scaffolding for cells, collagen-based hydrogels are regarded as ideal materials for tissue engineering applications since they can mimic the natural cellular microenvironment. [...] Read more.
Collagen is a natural and abundant polymer that serves multiple functions in both invertebrates and vertebrates. As collagen is the natural scaffolding for cells, collagen-based hydrogels are regarded as ideal materials for tissue engineering applications since they can mimic the natural cellular microenvironment. Chondrosia reniformis is a marine demosponge particularly rich in collagen, characterized by the presence of labile interfibrillar crosslinks similarly to those described in the mutable collagenous tissues (MCTs) of echinoderms. As a result single fibrils can be isolated using calcium-chelating and disulphide-reducing chemicals. In the present work we firstly describe a new extraction method that directly produces a highly hydrated hydrogel with interesting self-healing properties. The materials obtained were then biochemically and rheologically characterized. Our investigation has shown that the developed extraction procedure is able to extract collagen as well as other proteins and Glycosaminoglycans (GAG)-like molecules that give the collagenous hydrogel interesting and new rheological properties when compared to other described collagenous materials. The present work motivates further in-depth investigations towards the development of a new class of injectable collagenous hydrogels with tailored specifications. Full article
(This article belongs to the Special Issue Collagen from Marine Biological Source and Medical Applications)
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Article
Three New Cytotoxic Steroidal Glycosides Isolated from Conus pulicarius Collected in Kosrae, Micronesia
by Yeon-Ju Lee, Saem Han, Su Hyun Kim, Hyi-Seung Lee, Hee Jae Shin, Jong Seok Lee and Jihoon Lee
Mar. Drugs 2017, 15(12), 379; https://doi.org/10.3390/md15120379 - 4 Dec 2017
Cited by 7 | Viewed by 4118
Abstract
Three new sulfated steroidal glycosides (3–5), along with known cholesterol derivatives (1,2), were isolated from the visceral extract of the cone snail Conus pulicarius. The structure of each new compound was elucidated by nuclear [...] Read more.
Three new sulfated steroidal glycosides (3–5), along with known cholesterol derivatives (1,2), were isolated from the visceral extract of the cone snail Conus pulicarius. The structure of each new compound was elucidated by nuclear magnetic resonance spectroscopy and high-resolution mass spectrometry. The three new compounds exhibited significant in vitro cytotoxicity (GI50 values down to 0.49 μM) against the K562 human leukemia cell line. Full article
(This article belongs to the Special Issue Marine Glycosides)
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Article
Lobocrassin B Induces Apoptosis of Human Lung Cancer and Inhibits Tumor Xenograft Growth
by Meng-Xian Lin, Shen-Hao Lin, Yi-Rong Li, Ya-Hsuan Chao, Ching-Hsiung Lin, Jui-Hsin Su and Chi-Chien Lin
Mar. Drugs 2017, 15(12), 378; https://doi.org/10.3390/md15120378 - 4 Dec 2017
Cited by 12 | Viewed by 4653
Abstract
Lobocrassin B, a natural cembrane-type compound isolated from the soft coral Lobophytum crassum, has been shown to have significant biological effects, including anticancer activity. As the most common cause of cancer mortality worldwide, lung cancer remains a major concern threatening human health. [...] Read more.
Lobocrassin B, a natural cembrane-type compound isolated from the soft coral Lobophytum crassum, has been shown to have significant biological effects, including anticancer activity. As the most common cause of cancer mortality worldwide, lung cancer remains a major concern threatening human health. In the current study, we conducted in vitro experiments to demonstrate the inhibiting effect of Lobocrassin B on CL1-5 and H520 human lung cancer cells growth and to explore the underlying mechanisms, as well as in nude mice bearing CL1-5 tumor xenografts. Lobocrassin B exerted cytotoxic effects on lung cancer cells, as shown by decreasing cell viability, and inducing apoptosis, oxidative stress and mitochondrial dysfunction. In addition, the increased level of Bax, cleaved caspase-3, -9 and -8, and the suppression of Bcl-2 were observed in the Lobocrassin B treated cells. Moreover, in vivo assays verified the significance of these results, revealing that Lobocrassin B inhibited CL1-5 tumor xenograft growth and that inhibitory effects were accompanied by a marked increase in tumor cell apoptosis. In conclusion, the results suggested that Lobocrassin B could be a potential anticancer compound for its propensity to inhibit growth and induce apoptosis in human lung cancer cells. Full article
(This article belongs to the Special Issue In Vitro and In Vivo Approaches in the Driving Seat of Marine Drugs Discovery)
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Article
Optimization of Collagenase Production by Pseudoalteromonas sp. SJN2 and Application of Collagenases in the Preparation of Antioxidative Hydrolysates
by Xinghao Yang, Xiao Xiao, Dan Liu, Ribang Wu, Cuiling Wu, Jiang Zhang, Jiafeng Huang, Binqiang Liao and Hailun He
Mar. Drugs 2017, 15(12), 377; https://doi.org/10.3390/md15120377 - 4 Dec 2017
Cited by 26 | Viewed by 5898
Abstract
Collagenases are the most important group of commercially-produced enzymes. However, even though biological resources are abundant in the sea, very few of these commercially popular enzymes are from marine sources, especially from marine bacteria. We optimized the production of marine collagenases by Pseudoalteromonas [...] Read more.
Collagenases are the most important group of commercially-produced enzymes. However, even though biological resources are abundant in the sea, very few of these commercially popular enzymes are from marine sources, especially from marine bacteria. We optimized the production of marine collagenases by Pseudoalteromonas sp. SJN2 and investigated the antioxidant activities of the hydrolysates. Media components and culture conditions associated with marine collagenase production by Pseudoalteromonas sp. SJN2 were optimized by statistical methods, namely Plackett–Burman design and response surface methodology (RSM). Furthermore, the marine collagenases produced by Pseudoalteromonas sp. SJN2 were seen to efficiently hydrolyze marine collagens extracted from fish by-products, and remarkable antioxidant capacities of the enzymatic hydrolysates were shown by DPPH radical scavenging and oxygen radical absorbance capacity (ORAC) tests. The final optimized fermentation conditions were as follows: soybean powder, 34.23 g·L−1; culture time, 3.72 d; and temperature, 17.32 °C. Under the optimal fermentation conditions, the experimental collagenase yield obtained was 322.58 ± 9.61 U·mL−1, which was in agreement with the predicted yield of 306.68 U·mL−1. Collagen from Spanish mackerel bone, seabream scale and octopus flesh also showed higher DPPH radical scavenging rates and ORAC values after hydrolysis by the collagenase. This study may have implications for the development and use of marine collagenases. Moreover, seafood waste containing beneficial collagen could be used to produce antioxidant peptides by proteolysis. Full article
(This article belongs to the Special Issue Marine Enzymes: Sources, Biochemistry and Bioprocesses for Marine Biotechnology)
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Article
The Anti-Inflammatory Effect and Structure of EPCP1-2 from Crypthecodinium cohnii via Modulation of TLR4-NF-κB Pathways in LPS-Induced RAW 264.7 Cells
by Xiaolei Ma, Baolong Xie, Jin Du, Aijun Zhang, Jianan Hao, Shuxun Wang, Jing Wang and Junrui Cao
Mar. Drugs 2017, 15(12), 376; https://doi.org/10.3390/md15120376 - 1 Dec 2017
Cited by 14 | Viewed by 5338
Abstract
Exopolysaccharide from Crypthecodinium cohnii (EPCP1-2) is a marine exopolysaccharide that evidences a variety of biological activities. We isolated a neutral polysaccharide from the fermentation liquid of Crypthecodinium cohnii (CP). In this study, a polysaccharide that is derived from Crypthecodinium cohnii were analyzed and [...] Read more.
Exopolysaccharide from Crypthecodinium cohnii (EPCP1-2) is a marine exopolysaccharide that evidences a variety of biological activities. We isolated a neutral polysaccharide from the fermentation liquid of Crypthecodinium cohnii (CP). In this study, a polysaccharide that is derived from Crypthecodinium cohnii were analyzed and its anti-inflammatory effect was evaluated on protein expression of toll-like receptor 4 and nuclear factor κB pathways in macrophages. The structural characteristics of EPCP1-2 were characterized by GC (gas chromatography) and GC-MS (gas Chromatography-Mass Spectrometer) analyses. The molecular weight was about 82.5 kDa. The main chain of EPCP1-2 consisted of (1→6)-linked mannopyranosyl, (1→6)-linked glucopyranosyl, branched-chain consisted of (1→3,6)-linked galactopyranosyl and terminal consisted of t-l-Rhapyranosyl. The in vitro anti-inflammatory activity was representated through assay of proliferation rate, pro-inflammatory factor (NO) and expressions of proteins on RAW 264.7, the macrophage cell line. The results revealed that EPCP1-2 exhibited significant anti-inflammatory activity by regulating the expression of toll-like receptor 4, mitogen-activated protein kinases, and Nuclear Factor-κB protein. Full article
(This article belongs to the Collection Marine Polysaccharides)
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Article
A New Dihydrochromone Dimer and Other Secondary Metabolites from Cultures of the Marine Sponge-Associated Fungi Neosartorya fennelliae KUFA 0811 and Neosartorya tsunodae KUFC 9213
by Decha Kumla, Tin Shine Aung, Suradet Buttachon, Tida Dethoup, Luís Gales, José A. Pereira, Ângela Inácio, Paulo M. Costa, Michael Lee, Nazim Sekeroglu, Artur M. S. Silva, Madalena M. M. Pinto and Anake Kijjoa
Mar. Drugs 2017, 15(12), 375; https://doi.org/10.3390/md15120375 - 1 Dec 2017
Cited by 37 | Viewed by 7926
Abstract
A previously unreported dihydrochromone dimer, paecilin E (1), was isolated, together with eleven known compounds: β-sitostenone, ergosta-4,6,8 (14), 22-tetraen-3-one, cyathisterone, byssochlamic acid, dehydromevalonic acid lactone, chevalone B, aszonalenin, dankasterone A (2), helvolic acid, secalonic acid A and fellutanine A, [...] Read more.
A previously unreported dihydrochromone dimer, paecilin E (1), was isolated, together with eleven known compounds: β-sitostenone, ergosta-4,6,8 (14), 22-tetraen-3-one, cyathisterone, byssochlamic acid, dehydromevalonic acid lactone, chevalone B, aszonalenin, dankasterone A (2), helvolic acid, secalonic acid A and fellutanine A, from the culture filtrate extract of the marine sponge-associated fungus Neosartorya fennelliae KUFA 0811. Nine previously reported metabolites, including a chromanol derivative (3), (3β, 5α, 22E), 3,5-dihydroxyergosta-7,22-dien-6-one (4), byssochlamic acid, hopan-3β,22-diol, chevalone C, sartorypyrone B, helvolic acid, lumichrome and the alkaloid harmane were isolated from the culture of the marine-sponge associated fungus Neosartorya tsunodae KUFC 9213. Paecilin E (1), dankasterone A (2), a chromanol derivative (3), (3β, 5α, 22E)-3,5-dihydroxyergosta-7,22-dien-6-one (4), hopan-3β,22-diol (5), lumichrome (6), and harmane (7) were tested for their antibacterial activity against Gram-positive and Gram-negative reference and multidrug-resistant strains isolated from the environment. While paecilin E (1) was active against S. aureus ATCC 29213 and E. faecalis ATCC 29212, dankastetrone A (2) was only effective against E. faecalis ATCC 29212 and the multidrug-resistant VRE E. faecalis A5/102. Both compounds neither inhibit biofilm mass production in any of the strains at the concentrations tested nor exhibit synergistic association with antibiotics. Full article
(This article belongs to the Special Issue Marine Products for Health and Beauty)
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Article
Chemical Diversity from a Chinese Marine Red Alga, Symphyocladia latiuscula
by Xiuli Xu, Haijin Yang, Zeinab G. Khalil, Liyuan Yin, Xue Xiao, Pratik Neupane, Paul V. Bernhardt, Angela A. Salim, Fuhang Song and Robert J. Capon
Mar. Drugs 2017, 15(12), 374; https://doi.org/10.3390/md15120374 - 1 Dec 2017
Cited by 13 | Viewed by 4496
Abstract
This study describes an investigation into secondary metabolites that are produced by a marine red alga, Symphyocladia latiuscula, which was collected from coastal waters off Qingdao, China. A combination of normal, reversed phase, and gel chromatography was used to isolate six citric [...] Read more.
This study describes an investigation into secondary metabolites that are produced by a marine red alga, Symphyocladia latiuscula, which was collected from coastal waters off Qingdao, China. A combination of normal, reversed phase, and gel chromatography was used to isolate six citric acid derived natural products, aconitates A–F (1–6), together with two known and ten new polybrominated phenols, symphyocladins C/D (7a/b), and symphyocladins H–Q (8a/b, 9a/b and 10–15), respectively. Structure elucidation was achieved by detailed spectroscopic (including X-ray crystallographic) analysis. We propose a plausible and convergent biosynthetic pathway involving a key quinone methide intermediate, linking aconitates and symphyocladins. Full article
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Review
Structural Insights into the Cytotoxic Mechanism of Vibrio parahaemolyticus PirAvp and PirBvp Toxins
by Shin-Jen Lin, Kai-Cheng Hsu and Hao-Ching Wang
Mar. Drugs 2017, 15(12), 373; https://doi.org/10.3390/md15120373 - 1 Dec 2017
Cited by 48 | Viewed by 7620
Abstract
In aquaculture, shrimp farming is a popular field. The benefits of shrimp farming include a relatively short grow-out time, high sale price, and good cost recovery. However, outbreaks of serious diseases inflict serious losses, and acute hepatopancreatic necrosis disease (AHPND) is an emerging [...] Read more.
In aquaculture, shrimp farming is a popular field. The benefits of shrimp farming include a relatively short grow-out time, high sale price, and good cost recovery. However, outbreaks of serious diseases inflict serious losses, and acute hepatopancreatic necrosis disease (AHPND) is an emerging challenge to this industry. In South American white shrimp (Penaeus vannamei) and grass shrimp (Penaeus monodon), this disease has a 70–100% mortality. The pathogenic agent of AHPND is a specific strain of Vibrio parahaemolyticus which contains PirAvp and PirBvp toxins encoded in the pVA1 plasmid. PirAvp and PirBvp have been shown to cause the typical histological symptoms of AHPND in infected shrimps, and in this review, we will focus on our structural understanding of these toxins. By analyzing their structures, a possible cytotoxic mechanism, as well as strategies for anti-AHPND drug design, is proposed. Full article
(This article belongs to the Special Issue Marine Bacterial Toxins)
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Short Note
Effect of Marine-Derived Ice-Binding Proteins on the Cryopreservation of Marine Microalgae
by Hak Jun Kim, Bon-Won Koo, Doa Kim, Ye Seul Seo and Yoon Kwon Nam
Mar. Drugs 2017, 15(12), 372; https://doi.org/10.3390/md15120372 - 1 Dec 2017
Cited by 7 | Viewed by 4051
Abstract
Ice-binding protein (IBPs) protect cells from cryo-injury during cryopreservation by inhibiting ice recrystallization (IR), which is a main cause of cell death. In the present study, we employed two IBPs, one, designated LeIBP from Arctic yeast, and the other, designated FfIBP from Antarctic [...] Read more.
Ice-binding protein (IBPs) protect cells from cryo-injury during cryopreservation by inhibiting ice recrystallization (IR), which is a main cause of cell death. In the present study, we employed two IBPs, one, designated LeIBP from Arctic yeast, and the other, designated FfIBP from Antarctic sea ice bacterium, in the cryopreservation of three economically valuable marine microalgae, Isochrysis galbana, Pavlova viridis, and Chlamydomonas coccoides. Both of the IBPs showed IR inhibition in f/2 medium containing 10% DMSO, indicating that they retain their function in freezing media. Microalgal cells were frozen in 10% DMSO with or without IBP. Post-thaw viability exhibited that the supplementation of IBPs increased the viability of all cryopreserved cells. LeIBP was effective in P. viridis and C. coccoides, while FfIBP was in I. galbana. The cryopreservative effect was more drastic with P. viridis when 0.05 mg/mL LeIBP was used. These results clearly demonstrate that IBPs could improve the viability of cryopreserved microalgal cells. Full article
(This article belongs to the Special Issue Marine Ice-binding Proteins and Their Mimetics: Structure, Function, and Application)
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Article
Inhibitors of Serine Proteases from a Microcystis sp. Bloom Material Collected from Timurim Reservoir, Israel
by Rawan Hasan-Amer and Shmuel Carmeli
Mar. Drugs 2017, 15(12), 371; https://doi.org/10.3390/md15120371 - 1 Dec 2017
Cited by 8 | Viewed by 4476
Abstract
Two new natural products, micropeptin TR1058 (1) and aeruginosin TR642 (2), were isolated from the hydrophilic extract of bloom material of Microcystis sp. collected from the Timurim water reservoir in Israel. The structures of compounds 1 and 2 were [...] Read more.
Two new natural products, micropeptin TR1058 (1) and aeruginosin TR642 (2), were isolated from the hydrophilic extract of bloom material of Microcystis sp. collected from the Timurim water reservoir in Israel. The structures of compounds 1 and 2 were determined using 1D and 2D NMR spectroscopy and HR ESI MS and MS/MS techniques. Micropeptin TR1058 (1) was extremely unstable under the isolation conditions, and several degradation products were identified. NMR analysis of aeruginosin TR642 (2) revealed a mixture of eight isomers, and elucidation of its structure was challenging. Aeruginosin TR642 contains a 4,5-didehydroaraginal subunit that has not been described before. Micropeptin TR1058 (1) inhibited chymotrypsin with an IC50 of 6.78 µM, and aeruginosin TR642 (2) inhibited trypsin and thrombin with inhibition concentration (IC50) values of 3.80 and 0.85 µM, respectively. The structures and biological activities of the new compounds are discussed. Full article
(This article belongs to the Special Issue Compounds from Cyanobacteria II)
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Article
Chitosan Nanoparticles as a Mucoadhesive Drug Delivery System for Ocular Administration
by Mariana M. Silva, Raquel Calado, Joana Marto, Ana Bettencourt, António J. Almeida and Lídia M. D. Gonçalves
Mar. Drugs 2017, 15(12), 370; https://doi.org/10.3390/md15120370 - 1 Dec 2017
Cited by 191 | Viewed by 10606
Abstract
Pharmaceutical approaches based on nanotechnologies and the development of eye drops composed of the mucoadhesive polymers chitosan and hyaluronic acid are emerging strategies for the efficient treatment of ocular diseases. These innovative nanoparticulate systems aim to increase drugs’ bioavailability at the ocular surface. [...] Read more.
Pharmaceutical approaches based on nanotechnologies and the development of eye drops composed of the mucoadhesive polymers chitosan and hyaluronic acid are emerging strategies for the efficient treatment of ocular diseases. These innovative nanoparticulate systems aim to increase drugs’ bioavailability at the ocular surface. For the successful development of these systems, the evaluation of mucoahesiveness (the interaction between the ocular delivery system and mucins present on the eye) is of utmost importance. In this context, the aim of the present work was to investigate the mucoadhesivity of a novel nanoparticle eye drop formulation containing an antibiotic (ceftazidime) intended to treat eye infections. Eye drop formulations comprised a polymer (hydroxypropyl) methyl cellulose (HPMC) 0.75% (w/v) in an isotonic solution incorporating chitosan/sodium tripolyphosphate (TPP)-hyaluronic acid-based nanoparticles containing ceftazidime. The viscosity of the nanoparticles, and the gels incorporating the nanoparticles were characterized in contact with mucin at different mass ratios, allowing the calculation of the rheological synergism parameter (∆η). Results showed that at different nanoparticle eye formulation:mucin weight ratios, a minimum in viscosity occurred which resulted in a negative rheological synergism. Additionally, the results highlighted the mucoadhesivity of the novel ocular formulation and its ability to interact with the ocular surface, thus increasing the drug residence time in the eye. Moreover, the in vitro release and permeation studies showed a prolonged drug release profile from the chitosan/TPP-hyaluronic acid nanoparticles gel formulation. Furthermore, the gel formulations were not cytotoxic on ARPE-19 and HEK293T cell lines, evaluated by the metabolic and membrane integrity tests. The formulation was stable and the drug active, as shown by microbiological studies. In conclusion, chitosan/TPP-hyaluronic acid nanoparticle eye drop formulations are a promising platform for ocular drug delivery with enhanced mucoadhesive properties. Full article
(This article belongs to the Special Issue Marine Oligosaccharides and Polysaccharides)
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Article
The Marine Fungi Rhodotorula sp. (Strain CNYC4007) as a Potential Feed Source for Fish Larvae Nutrition
by M. Barra, A. Llanos-Rivera, F. Cruzat, N. Pino-Maureira and R. R. González-Saldía
Mar. Drugs 2017, 15(12), 369; https://doi.org/10.3390/md15120369 - 1 Dec 2017
Cited by 2 | Viewed by 4650
Abstract
Fish oil is used in the production of feed for cultured fish owing to its high polyunsaturated fatty acid content (PUFA). The over-exploitation of fisheries and events like “El Niño” are reducing the fish oil supply. Some marine microorganisms are considered potentially as [...] Read more.
Fish oil is used in the production of feed for cultured fish owing to its high polyunsaturated fatty acid content (PUFA). The over-exploitation of fisheries and events like “El Niño” are reducing the fish oil supply. Some marine microorganisms are considered potentially as alternative fatty acid sources. This study assesses a strain of Rhodotorula sp. (strain CNYC4007; 27% docosahexaenoic acid (DHA) of total fatty acids), as feed for fish larvae. The total length and ribonucleic acid (RNA)/deoxyribonucleic acid (DNA) ratio of Danio rerio larvae was determined at first feeding at six and 12 days old (post-yolk absorption larvae). Larvae fed with microencapsulated Rhodotorula sp. CNYC4007 had a significantly higher RNA/DNA ratio than control group (C1). At six days post-yolk absorption group, the RNA/DNA ratio of larvae fed with Rhodotorula sp. bioencapsulated in Brachionus sp. was significantly higher than control group fed with a commercial diet high in DHA (C2-DHA). Finally, at 12 days post-yolk absorption, the RNA/DNA ratio was significantly higher in larvae fed with Rhodotorula sp. CNYC4007 and C2-DHA (both bioencapsulated in Artemia sp. nauplii) than in control group (C1). These results suggest that Rhodotorula sp. CNYC4007 can be an alternative source of DHA for feeding fish at larval stage, providing a sustainable source of fatty acids. Full article
(This article belongs to the Special Issue Marine Lipids 2017)
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Article
α-Glucosidase and Protein Tyrosine Phosphatase 1B Inhibitory Activity of Plastoquinones from Marine Brown Alga Sargassum serratifolium
by Md. Yousof Ali, Da Hye Kim, Su Hui Seong, Hyeung-Rak Kim, Hyun Ah Jung and Jae Sue Choi
Mar. Drugs 2017, 15(12), 368; https://doi.org/10.3390/md15120368 - 1 Dec 2017
Cited by 58 | Viewed by 7060
Abstract
Sargassum serratifolium C. Agardh (Phaeophyceae, Fucales) is a marine brown alga that belongs to the family Sargassaceae. It is widely distributed throughout coastal areas of Korea and Japan. S. serratifolium has been found to contain high concentrations of plastoquinones, which have strong anti-cancer, [...] Read more.
Sargassum serratifolium C. Agardh (Phaeophyceae, Fucales) is a marine brown alga that belongs to the family Sargassaceae. It is widely distributed throughout coastal areas of Korea and Japan. S. serratifolium has been found to contain high concentrations of plastoquinones, which have strong anti-cancer, anti-inflammatory, antioxidant, and neuroprotective activity. This study aims to investigate the anti-diabetic activity of S. serratifolium and its major constituents through inhibition of protein tyrosine phosphatase 1B (PTP1B), α-glucosidase, and ONOO−-mediated albumin nitration. S. serratifolium ethanolic extract and fractions exhibited broad PTP1B and α-glucosidase inhibitory activity (IC50, 1.83~7.04 and 3.16~24.16 µg/mL for PTP1B and α-glucosidase, respectively). In an attempt to identify bioactive compounds, three plastoquinones (sargahydroquinoic acid, sargachromenol and sargaquinoic acid) were isolated from the active n-hexane fraction of S. serratifolium. All three plastoquinones exhibited dose-dependent inhibitory activity against PTP1B in the IC50 range of 5.14–14.15 µM, while sargachromenol and sargaquinoic acid showed dose-dependent inhibitory activity against α-glucosidase (IC50 42.41 ± 3.09 and 96.17 ± 3.48 µM, respectively). In the kinetic study of PTP1B enzyme inhibition, sargahydroquinoic acid and sargaquinoic acid led to mixed-type inhibition, whereas sargachromenol displayed noncompetitive-type inhibition. Moreover, plastoquinones dose-dependently inhibited ONOO−-mediated albumin nitration. Docking simulations of these plastoquinones demonstrated negative binding energies and close proximity to residues in the binding pocket of PTP1B and α-glucosidase, indicating that these plastoquinones have high affinity and tight binding capacity towards the active site of the enzymes. These results demonstrate that S. serratifolium and its major plastoquinones may have the potential as functional food ingredients for the prevention and treatment of type 2 diabetes. Full article
(This article belongs to the Special Issue Bioactive Compounds from Marine Microbes - II)
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Article
Three New Malyngamides from the Marine Cyanobacterium Moorea producens
by Kosuke Sueyoshi, Aki Yamano, Kaori Ozaki, Shimpei Sumimoto, Arihiro Iwasaki, Kiyotake Suenaga and Toshiaki Teruya
Mar. Drugs 2017, 15(12), 367; https://doi.org/10.3390/md15120367 - 29 Nov 2017
Cited by 23 | Viewed by 5657
Abstract
Three new compounds of the malyngamide series, 6,8-di-O-acetylmalyngamide 2 (1), 6-O-acetylmalyngamide 2 (2), and N-demethyl-isomalyngamide I (3), were isolated from the marine cyanobacterium Moorea producens. Their structures were determined by spectroscopic [...] Read more.
Three new compounds of the malyngamide series, 6,8-di-O-acetylmalyngamide 2 (1), 6-O-acetylmalyngamide 2 (2), and N-demethyl-isomalyngamide I (3), were isolated from the marine cyanobacterium Moorea producens. Their structures were determined by spectroscopic analysis and chemical derivatization and degradation. These compounds stimulated glucose uptake in cultured L6 myotubes. In particular, 6,8-di-O-acetylmalyngamide 2 (1) showed potent activity and activated adenosine monophosphate-activated protein kinase (AMPK). Full article
(This article belongs to the Special Issue Marine Bioactive Natural Product Studies in Asia)
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Article
Computer-Aided Drug Design Applied to Marine Drug Discovery: Meridianins as Alzheimer’s Disease Therapeutic Agents
by Laura Llorach-Pares, Alfons Nonell-Canals, Melchor Sanchez-Martinez and Conxita Avila
Mar. Drugs 2017, 15(12), 366; https://doi.org/10.3390/md15120366 - 27 Nov 2017
Cited by 40 | Viewed by 9419
Abstract
Computer-aided drug discovery/design (CADD) techniques allow the identification of natural products that are capable of modulating protein functions in pathogenesis-related pathways, constituting one of the most promising lines followed in drug discovery. In this paper, we computationally evaluated and reported the inhibitory activity [...] Read more.
Computer-aided drug discovery/design (CADD) techniques allow the identification of natural products that are capable of modulating protein functions in pathogenesis-related pathways, constituting one of the most promising lines followed in drug discovery. In this paper, we computationally evaluated and reported the inhibitory activity found in meridianins A–G, a group of marine indole alkaloids isolated from the marine tunicate Aplidium, against various protein kinases involved in Alzheimer’s disease (AD), a neurodegenerative pathology characterized by the presence of neurofibrillary tangles (NFT). Balance splitting between tau kinase and phosphate activities caused tau hyperphosphorylation and, thereby, its aggregation and NTF formation. Inhibition of specific kinases involved in its phosphorylation pathway could be one of the key strategies to reverse tau hyperphosphorylation and would represent an approach to develop drugs to palliate AD symptoms. Meridianins bind to the adenosine triphosphate (ATP) binding site of certain protein kinases, acting as ATP competitive inhibitors. These compounds show very promising scaffolds to design new drugs against AD, which could act over tau protein kinases Glycogen synthetase kinase-3 Beta (GSK3β) and Casein kinase 1 delta (CK1δ, CK1D or KC1D), and dual specificity kinases as dual specificity tyrosine phosphorylation regulated kinase 1 (DYRK1A) and cdc2-like kinases (CLK1). This work is aimed to highlight the role of CADD techniques in marine drug discovery and to provide precise information regarding the binding mode and strength of meridianins against several protein kinases that could help in the future development of anti-AD drugs. Full article
(This article belongs to the Special Issue Bioactive Marine Natural Compounds with Heterocyclic Motifs in their Structure)
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Article
Chemical Profiling and Bioactivity of Body Wall Lipids from Strongylocentrotus droebachiensis
by Alexander N. Shikov, Into Laakso, Olga N. Pozharitskaya, Tuulikki Seppänen-Laakso, Anna S. Krishtopina, Marina N. Makarova, Heikki Vuorela and Valery Makarov
Mar. Drugs 2017, 15(12), 365; https://doi.org/10.3390/md15120365 - 24 Nov 2017
Cited by 10 | Viewed by 5954
Abstract
The lipids from gonads and polyhydroxynaphthoquinone pigments from body walls of sea urchins are intensively studied. However, little is known about the body wall (BW) lipids. Ethanol extract (55 °C) contained about equal amounts of saturated (SaFA) and monounsaturated fatty acids (MUFA) representing [...] Read more.
The lipids from gonads and polyhydroxynaphthoquinone pigments from body walls of sea urchins are intensively studied. However, little is known about the body wall (BW) lipids. Ethanol extract (55 °C) contained about equal amounts of saturated (SaFA) and monounsaturated fatty acids (MUFA) representing 60% of total fatty acids, with myristic, palmitic and eicosenoic acids as major SaFAs and MUFAs, respectively. Non-methylene-interrupted dienes (13%) were composed of eicosadienoic and docosadienoic acids. Long-chain polyunsaturated fatty acids (LC-PUFA) included two main components, n6 arachidonic and n3 eicosapentaenoic acids, even with equal concentrations (15 μg/mg) and a balanced n6/n3 PUFA ratio (0.86). The UPLC-ELSD analysis showed that a great majority of the lipids (80%) in the ethanolic extract were phosphatidylcholine (60 μg/mg) and phosphatidylethanolamine (40 μg/mg), while the proportion of neutral lipids remained lower than 20%. In addition, alkoxyglycerol derivatives—chimyl, selachyl, and batyl alcohols—were quantified. We have assumed that the mechanism of action of body wall lipids in the present study is via the inhibition of MAPK p38, COX-1, and COX-2. Our findings open the prospective to utilize this lipid fraction as a source for the development of drugs with anti-inflammatory activity. Full article
(This article belongs to the Special Issue Marine Lipids 2017)
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