Marine Drugs

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Open AccessArticle

Isolation and Total Synthesis of Stolonines A–C, Unique Taurine Amides from the Australian Marine Tunicate Cnemidocarpa stolonifera

by Trong D. Tran, Ngoc B. Pham, Merrick Ekins, John N. A. Hooper and Ronald J. Quinn

Mar. Drugs 2015, 13(7), 4556-4575; https://doi.org/10.3390/md13074556 - 22 Jul 2015

Cited by 28 | Viewed by 8991

Abstract

Cnemidocarpa stolonifera is an underexplored marine tunicate that only occurs on the tropical to subtropical East Coast of Australia, with only two pyridoacridine compounds reported previously. Qualitative analysis of the lead-like enhanced fractions of C. stolonifera by LC-MS dual electrospray ionization coupled with [...] Read more.

Cnemidocarpa stolonifera is an underexplored marine tunicate that only occurs on the tropical to subtropical East Coast of Australia, with only two pyridoacridine compounds reported previously. Qualitative analysis of the lead-like enhanced fractions of C. stolonifera by LC-MS dual electrospray ionization coupled with PDA and ELSD detectors led to the identification of three new natural products, stolonines A–C (1–3), belonging to the taurine amide structure class. Structures of the new compounds were determined by NMR and MS analyses and later verified by total synthesis. This is the first time that the conjugates of taurine with 3-indoleglyoxylic acid, quinoline-2-carboxylic acid and β-carboline-3-carboxylic acid present in stolonines A–C (1–3), respectively, have been reported. An immunofluorescence assay on PC3 cells indicated that compounds 1 and 3 increased cell size, induced mitochondrial texture elongation, and caused apoptosis in PC3 cells. Full article

(This article belongs to the Special Issue Marine Bioactive Natural Product Studies—A Southern Hemisphere Perspective)

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955 KiB

Open AccessArticle

Structural Investigation of the Oligosaccharide Portion Isolated from the Lipooligosaccharide of the Permafrost Psychrophile Psychrobacter arcticus 273-4

by Angela Casillo, Ermenegilda Parrilli, Sannino Filomena, Buko Lindner, Rosa Lanzetta, Michelangelo Parrilli, Maria Luisa Tutino and Maria Michela Corsaro

Mar. Drugs 2015, 13(7), 4539-4555; https://doi.org/10.3390/md13074539 - 22 Jul 2015

Cited by 23 | Viewed by 6002

Abstract

Psychrophilic microorganisms have successfully colonized all permanently cold environments from the deep sea to mountain and polar regions. The ability of an organism to survive and grow in cryoenviroments depends on a number of adaptive strategies aimed at maintaining vital cellular functions at [...] Read more.

Psychrophilic microorganisms have successfully colonized all permanently cold environments from the deep sea to mountain and polar regions. The ability of an organism to survive and grow in cryoenviroments depends on a number of adaptive strategies aimed at maintaining vital cellular functions at subzero temperatures, which include the structural modifications of the membrane. To understand the role of the membrane in the adaptation, it is necessary to characterize the cell-wall components, such as the lipopolysaccharides, that represent the major constituent of the outer membrane. The aim of this study was to investigate the structure of the carbohydrate backbone of the lipooligosaccharide (LOS) isolated from the cold-adapted Psychrobacter arcticus 273-4. The strain, isolated from a 20,000-to-30,000-year-old continuously frozen permafrost in Siberia, was cultivated at 4 °C. The LOS was isolated from dry cells and analyzed by means of chemical methods. In particular, it was degraded either by mild acid hydrolysis or by hydrazinolysis and investigated in detail by ¹H and ¹³C NMR spectroscopy and by ESI FT-ICR mass spectrometry. The oligosaccharide was characterized by the substitution of the heptose residue, usually linked to Kdo in the inner core, with a glucose, and for the unusual presence of N-acetylmuramic acid. Full article

(This article belongs to the Special Issue Marine Glycoconjugates)

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Open AccessReview

Potential Antiviral Agents from Marine Fungi: An Overview

by Soheil Zorofchian Moghadamtousi, Sonia Nikzad, Habsah Abdul Kadir, Sazaly Abubakar and Keivan Zandi

Mar. Drugs 2015, 13(7), 4520-4538; https://doi.org/10.3390/md13074520 - 22 Jul 2015

Cited by 90 | Viewed by 12805

Abstract

Biodiversity of the marine world is only partially subjected to detailed scientific scrutiny in comparison to terrestrial life. Life in the marine world depends heavily on marine fungi scavenging the oceans of lifeless plants and animals and entering them into the nutrient cycle [...] Read more.

Biodiversity of the marine world is only partially subjected to detailed scientific scrutiny in comparison to terrestrial life. Life in the marine world depends heavily on marine fungi scavenging the oceans of lifeless plants and animals and entering them into the nutrient cycle by. Approximately 150 to 200 new compounds, including alkaloids, sesquiterpenes, polyketides, and aromatic compounds, are identified from marine fungi annually. In recent years, numerous investigations demonstrated the tremendous potential of marine fungi as a promising source to develop new antivirals against different important viruses, including herpes simplex viruses, the human immunodeficiency virus, and the influenza virus. Various genera of marine fungi such as Aspergillus, Penicillium, Cladosporium, and Fusarium were subjected to compound isolation and antiviral studies, which led to an illustration of the strong antiviral activity of a variety of marine fungi-derived compounds. The present review strives to summarize all available knowledge on active compounds isolated from marine fungi with antiviral activity. Full article

(This article belongs to the Special Issue Bioactive Compounds from Marine Fungi)

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Open AccessArticle

Evaluation of Potential Thrombin Inhibitors from the White Mangrove (Laguncularia racemosa (L.) C.F. Gaertn.)

by Caroline Fabri Bittencourt Rodrigues, Henrique Hessel Gaeta, Mariana Novo Belchor, Marcelo José Pena Ferreira, Marcus Vinícius Terashima Pinho, Daniela De Oliveira Toyama and Marcos Hikari Toyama

Mar. Drugs 2015, 13(7), 4505-4519; https://doi.org/10.3390/md13074505 - 21 Jul 2015

Cited by 14 | Viewed by 6174

Abstract

The aim of this work was to verify the effects of methanol (MeOH) and hydroalcoholic (HA) extracts and their respective partition phases obtained from white mangrove (Laguncularia racemosa (L.) C.F. Gaertn.) leaves on human thrombin activity. Among the extracts and phases tested, [...] Read more.

The aim of this work was to verify the effects of methanol (MeOH) and hydroalcoholic (HA) extracts and their respective partition phases obtained from white mangrove (Laguncularia racemosa (L.) C.F. Gaertn.) leaves on human thrombin activity. Among the extracts and phases tested, only the ethyl acetate and butanolic partitions significantly inhibited human thrombin activity and the coagulation of plasma in the presence of this enzyme. Chromatographic analyses of the thrombin samples incubated with these phases revealed that different compounds were able to interact with thrombin. The butanolic phase of the MeOH extract had the most potent inhibitory effects, reducing enzymatic activity and thrombin-induced plasma coagulation. Two glycosylated flavonoids in this partition were identified as the most potent inhibitors of human thrombin activity, namely quercetin-3-O-arabinoside (QAra) and quercetin-3-O-rhamnoside (Qn). Chromatographic analyses of thrombin samples incubated with these flavonoids demonstrated the chemical modification of this enzyme, suggesting that the MeOH extract contained other compounds that both induced structural changes in thrombin and diminished its activity. In this article, we show that despite the near absence of the medical use of mangrove compounds, this plant contains natural compounds with potential therapeutic applications. Full article

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Open AccessArticle

Identification and Bioactivity of Compounds from the Mangrove Endophytic Fungus Alternaria sp.

by Jinhua Wang, Weijia Ding, Ruimin Wang, Yipeng Du, Huanliang Liu, Xuehua Kong and Chunyuan Li

Mar. Drugs 2015, 13(7), 4492-4504; https://doi.org/10.3390/md13074492 - 20 Jul 2015

Cited by 51 | Viewed by 6515

Abstract

Racemic new cyclohexenone and cyclopentenone derivatives, (±)-(4R*,5S*,6S*)-3-amino-4,5,6-trihydroxy-2-methoxy-5-methyl-2-cyclohexen-1-one (1) and (±)-(4S*,5S*)-2,4,5-trihydroxy-3-methoxy-4-methoxycarbonyl-5-methyl-2-cyclopenten-1-one (2), and two new xanthone derivatives 4-chloro-1,5-dihydroxy-3-hydroxymethyl-6-methoxycarbonyl-xanthen-9-one (3) and 2,8-dimethoxy-1,6-dimethoxycarbonyl-xanthen-9-one (4), along with one known [...] Read more.

Racemic new cyclohexenone and cyclopentenone derivatives, (±)-(4R*,5S*,6S*)-3-amino-4,5,6-trihydroxy-2-methoxy-5-methyl-2-cyclohexen-1-one (1) and (±)-(4S*,5S*)-2,4,5-trihydroxy-3-methoxy-4-methoxycarbonyl-5-methyl-2-cyclopenten-1-one (2), and two new xanthone derivatives 4-chloro-1,5-dihydroxy-3-hydroxymethyl-6-methoxycarbonyl-xanthen-9-one (3) and 2,8-dimethoxy-1,6-dimethoxycarbonyl-xanthen-9-one (4), along with one known compound, fischexanthone (5), were isolated from the culture of the mangrove endophytic fungus Alternaria sp. R6. The structures of these compounds were elucidated by analysis of their MS (Mass), one and two dimensional NMR (nuclear magnetic resonance) spectroscopic data. Compounds 1 and 2 exhibited potent ABTS [2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid)] scavenging activities with EC₅₀ values of 8.19 ± 0.15 and 16.09 ± 0.01 μM, respectively. In comparison to Triadimefon, compounds 2 and 3 exhibited inhibitory activities against Fusarium graminearum with minimal inhibitory concentration (MIC) values of 215.52 and 107.14 μM, respectively, and compound 3 exhibited antifungal activity against Calletotrichum musae with MIC value of 214.29 μM. Full article

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Open AccessArticle

Molecular Mechanisms by Which a Fucus vesiculosus Extract Mediates Cell Cycle Inhibition and Cell Death in Pancreatic Cancer Cells

by Ulf Geisen, Marion Zenthoefer, Matthias Peipp, Jannik Kerber, Johannes Plenge, Antonella Managò, Markus Fuhrmann, Roland Geyer, Steffen Hennig, Dieter Adam, Levent Piker, Gerald Rimbach and Holger Kalthoff

Mar. Drugs 2015, 13(7), 4470-4491; https://doi.org/10.3390/md13074470 - 20 Jul 2015

Cited by 30 | Viewed by 10283

Abstract

Pancreatic cancer is one of the most aggressive cancer entities, with an extremely poor 5-year survival rate. Therefore, novel therapeutic agents with specific modes of action are urgently needed. Marine organisms represent a promising source to identify new pharmacologically active substances. Secondary metabolites [...] Read more.

Pancreatic cancer is one of the most aggressive cancer entities, with an extremely poor 5-year survival rate. Therefore, novel therapeutic agents with specific modes of action are urgently needed. Marine organisms represent a promising source to identify new pharmacologically active substances. Secondary metabolites derived from marine algae are of particular interest. The present work describes cellular and molecular mechanisms induced by an HPLC-fractionated, hydrophilic extract derived from the Baltic brown seaweed Fucus vesiculosus (Fv1). Treatment with Fv1 resulted in a strong inhibition of viability in various pancreatic cancer cell lines. This extract inhibited the cell cycle of proliferating cells due to the up-regulation of cell cycle inhibitors, shown on the mRNA (microarray data) and protein level. As a result, cells were dying in a caspase-independent manner. Experiments with non-dividing cells showed that proliferation is a prerequisite for the effectiveness of Fv1. Importantly, Fv1 showed low cytotoxic activity against non-malignant resting T cells and terminally differentiated cells like erythrocytes. Interestingly, accelerated killing effects were observed in combination with inhibitors of autophagy. Our in vitro data suggest that Fv1 may represent a promising new agent that deserves further development towards clinical application. Full article

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Open AccessArticle

Marine Bromophenol Derivative 3,4-Dibromo-5-(2-bromo-3,4-dihydroxy-6-isopropoxymethyl benzyl)benzene-1,2-diol Protects Hepatocytes from Lipid-Induced Cell Damage and Insulin Resistance via PTP1B Inhibition

by Jiao Luo, Ning Wu, Bo Jiang, Lijun Wang, Shuaiyu Wang, Xiangqian Li, Baocheng Wang, Changhui Wang and Dayong Shi

Mar. Drugs 2015, 13(7), 4452-4469; https://doi.org/10.3390/md13074452 - 17 Jul 2015

Cited by 10 | Viewed by 7608

Abstract

3,4-Dibromo-5-(2-bromo-3,4-dihydroxy-6-isopropoxymethyl benzyl)benzene-1,2-diol (HPN) is a bromophenol derivative from the marine red alga Rhodomela confervoides. We have previously found that HPN exerted an anti-hyperglycemic property in db/db mouse model. In the present study, we found that HPN could protect HepG2 cells [...] Read more.

3,4-Dibromo-5-(2-bromo-3,4-dihydroxy-6-isopropoxymethyl benzyl)benzene-1,2-diol (HPN) is a bromophenol derivative from the marine red alga Rhodomela confervoides. We have previously found that HPN exerted an anti-hyperglycemic property in db/db mouse model. In the present study, we found that HPN could protect HepG2 cells against palmitate (PA)-induced cell death. Data also showed that HPN inhibited cell death mainly by blocking the cell apoptosis. Further studies demonstrated that HPN (especially at 1.0 μM) significantly restored insulin-stimulated tyrosine phosphorylation of IR and IRS1/2, and inhibited the PTP1B expression level in HepG2 cells. Furthermore, the expression of Akt was activated by HPN, and glucose uptake was significantly increased in PA-treated HepG2 cells. Our results suggest that HPN could protect hepatocytes from lipid-induced cell damage and insulin resistance via PTP1B inhibition. Thus, HPN can be considered to have potential for the development of anti-diabetic agent that could protect both hepatic cell mass and function. Full article

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Open AccessArticle

Low Molecular Weight Fucoidan Inhibits Tumor Angiogenesis through Downregulation of HIF-1/VEGF Signaling under Hypoxia

by Meng-Chuan Chen, Wen-Lin Hsu, Pai-An Hwang and Tz-Chong Chou

Mar. Drugs 2015, 13(7), 4436-4451; https://doi.org/10.3390/md13074436 - 17 Jul 2015

Cited by 129 | Viewed by 10461

Abstract

Activation of hypoxia-induced hypoxia-inducible factors-1 (HIF-1) plays a critical role in promoting tumor angiogenesis, growth and metastasis. Low molecular weight fucoidan (LMWF) is prepared from brown algae, and exhibits anticancer activity. However, whether LMWF attenuates hypoxia-induced angiogenesis in bladder cancer cells and the [...] Read more.

Activation of hypoxia-induced hypoxia-inducible factors-1 (HIF-1) plays a critical role in promoting tumor angiogenesis, growth and metastasis. Low molecular weight fucoidan (LMWF) is prepared from brown algae, and exhibits anticancer activity. However, whether LMWF attenuates hypoxia-induced angiogenesis in bladder cancer cells and the molecular mechanisms involved remain unclear. This is the first study to demonstrate that LMWF can inhibit hypoxia-stimulated H₂O₂ formation, HIF-1 accumulation and transcriptional activity vascular endothelial growth factor (VEGF) secretion, and the migration and invasion in hypoxic human bladder cancer cells (T24) cells. LMWF also downregulated hypoxia-activated phosphorylation of PI3K/AKT/mTOR/p70S6K/4EBP-1 signaling in T24 cells. Blocking PI3K/AKT or mTOR activity strongly diminished hypoxia-induced HIF-1α expression and VEGF secretion in T24 cells, supporting the involvement of PI3K/AKT/mTOR in the induction of HIF-1α and VEGF. Additionally, LMWF significantly attenuated angiogenesis in vitro and in vivo evidenced by reduction of tube formation of hypoxic human umbilical vascular endothelial cells and blood capillary generation in the tumor. Similarly, administration of LMWF also inhibited the HIF-1α and VEGF expression in vivo, accompanied by a reduction of tumor growth. In summary, under hypoxia conditions, the antiangiogenic activity of LMWF in bladder cancer may be associated with suppressing HIF-1/VEGF-regulated signaling pathway. Full article

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Open AccessArticle

Four New Sulfated Polar Steroids from the Far Eastern Starfish Leptasterias ochotensis: Structures and Activities

by Timofey V. Malyarenko, Olesya S. Malyarenko (Vishchuk), Natalia V. Ivanchina, Anatoly I. Kalinovsky, Roman S. Popov and Alla A. Kicha

Mar. Drugs 2015, 13(7), 4418-4435; https://doi.org/10.3390/md13074418 - 16 Jul 2015

Cited by 24 | Viewed by 6565

Abstract

Three new sulfated steroid monoglycosides, leptaochotensosides A–C (1–3), and a new sulfated polyhydroxylated steroid (4) were isolated from the alcoholic extract of the Far Eastern starfish Leptasterias ochotensis. The structures of compounds 1–4 were [...] Read more.

Three new sulfated steroid monoglycosides, leptaochotensosides A–C (1–3), and a new sulfated polyhydroxylated steroid (4) were isolated from the alcoholic extract of the Far Eastern starfish Leptasterias ochotensis. The structures of compounds 1–4 were established by extensive nuclear magnetic resonance (NMR) and electrospray ionization mass spectrometry (ESIMS) analyses and chemical transformations. Although the isolated compounds did not show any apparent cytotoxicity against melanoma RPMI-7951 and breast cancer T-47D cell lines, leptaochotensoside A (1) demonstrated inhibition of T-47D cell colony formation in a soft agar clonogenic assay at nontoxic doses. In addition, this compound decreased the epidermal growth factor (EGF)-induced colony formation of mouse epidermal JB6 Cl41 cells. The cancer preventive action of 1 is realized through regulation of mitogen-activated protein kinase (MAPK) signaling pathway. Full article

(This article belongs to the Special Issue Marine Secondary Metabolites)

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Open AccessArticle

Purification and Characterization of a Fucoidanase (FNase S) from a Marine Bacterium Sphingomonas paucimobilis PF-1

by Woo Jung Kim, Joo Woong Park, Jae Kweon Park, Doo Jin Choi and Yong Il Park

Mar. Drugs 2015, 13(7), 4398-4417; https://doi.org/10.3390/md13074398 - 16 Jul 2015

Cited by 23 | Viewed by 8280

Abstract

The Search for enzyme activities that efficiently degrade marine polysaccharides is becoming an increasingly important area for both structural analysis and production of lower-molecular weight oligosaccharides. In this study, an endo-acting fucoidanase that degrades Miyeokgui fucoidan (MF), a sulfated galactofucan isolated from [...] Read more.

The Search for enzyme activities that efficiently degrade marine polysaccharides is becoming an increasingly important area for both structural analysis and production of lower-molecular weight oligosaccharides. In this study, an endo-acting fucoidanase that degrades Miyeokgui fucoidan (MF), a sulfated galactofucan isolated from the sporophyll (called Miyeokgui in Korean) of Undaria pinnatifida, into smaller-sized galactofuco-oligosaccharides (1000–4000 Da) was purified from a marine bacterium, Sphingomonas paucimobilis PF-1, by ammonium sulfate precipitation, diethylaminoethyl (DEAE)-Sepharose column chromatography, and chromatofocusing. The specific activity of this enzyme was approximately 112-fold higher than that of the crude enzyme, and its molecular weight was approximately 130 kDa (FNase S), as determined by native gel electrophoresis and 130 (S1), 70 (S2) and 60 (S3) kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The optimum pH and temperature of FNase S were pH 6.0–7.0 and 40–45 °C, respectively. FNase S activity was enhanced by Mn²⁺ and Na⁺ (115.7% and 131.2%), but it was inhibited by Ca²⁺, K⁺, Ba²⁺, Cu²⁺ (96%, 83.7%, 84.3%, and 89.3%, respectively), each at 1 mM. The K_m, V_max and K_cat values of FNase S on MF were 1.7 mM, 0.62 mg·min⁻¹, and 0.38·S⁻¹, respectively. This enzyme could be a valuable tool for the structural analysis of fucoidans and production of bioactive fuco-oligosaccharides. Full article

(This article belongs to the Special Issue Marine Glycoconjugates)

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Open AccessArticle

A Phospholipid-Protein Complex from Krill with Antioxidative and Immunomodulating Properties Reduced Plasma Triacylglycerol and Hepatic Lipogenesis in Rats

by Marie S. Ramsvik, Bodil Bjørndal, Inge Bruheim, Pavol Bohov and Rolf K. Berge

Mar. Drugs 2015, 13(7), 4375-4397; https://doi.org/10.3390/md13074375 - 16 Jul 2015

Cited by 14 | Viewed by 7131

Abstract

Dietary intake of marine omega-3 polyunsaturated fatty acids (n-3 PUFAs) can change the plasma profile from atherogenic to cardioprotective. In addition, there is growing evidence that proteins of marine origin may have health benefits. We investigated a phospholipid-protein complex (PPC) from [...] Read more.

Dietary intake of marine omega-3 polyunsaturated fatty acids (n-3 PUFAs) can change the plasma profile from atherogenic to cardioprotective. In addition, there is growing evidence that proteins of marine origin may have health benefits. We investigated a phospholipid-protein complex (PPC) from krill that is hypothesized to influence lipid metabolism, inflammation, and redox status. Male Wistar rats were fed a control diet (2% soy oil, 8% lard, 20% casein), or diets where corresponding amounts of casein and lard were replaced with PPC at 3%, 6%, or 11% (wt %), for four weeks. Dietary supplementation with PPC resulted in significantly lower levels of plasma triacylglycerols in the 11% PPC-fed group, probably due to reduced hepatic lipogenesis. Plasma cholesterol levels were also reduced at the highest dose of PPC. In addition, the plasma and liver content of n-3 PUFAs increased while n-6 PUFAs decreased. This was associated with increased total antioxidant capacity in plasma and increased liver gene expression of mitochondrial superoxide dismutase (Sod2). Finally, a reduced plasma level of the inflammatory mediator interleukin-2 (IL-2) was detected in the PPC-fed animals. The present data show that PPC has lipid-lowering effects in rats, and may modulate risk factors related to cardiovascular disease progression. Full article

(This article belongs to the Special Issue Marine Lipids)

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Open AccessArticle

Lipids and Composition of Fatty Acids of Saccharina latissima Cultivated Year-Round in Integrated Multi-Trophic Aquaculture

by Gonçalo S. Marinho, Susan L. Holdt, Charlotte Jacobsen and Irini Angelidaki

Mar. Drugs 2015, 13(7), 4357-4374; https://doi.org/10.3390/md13074357 - 15 Jul 2015

Cited by 37 | Viewed by 7025

Abstract

This study is evaluating the seasonal lipid and fatty acid composition of the brown seaweed Saccharina latissima. Biomass was sampled throughout the year (bi-monthly) at the commercial cultivation site near a fish farm in an integrated multi-trophic aquaculture (IMTA) and at a [...] Read more.

This study is evaluating the seasonal lipid and fatty acid composition of the brown seaweed Saccharina latissima. Biomass was sampled throughout the year (bi-monthly) at the commercial cultivation site near a fish farm in an integrated multi-trophic aquaculture (IMTA) and at a reference site in Denmark (2013–2014). Generally, there was no difference in the biomass composition between sites; however, significant seasonal changes were found. The lipid concentration varied from 0.62%–0.88% dry weight (DW) in July to 3.33%–3.35% DW in November (p < 0.05) in both sites. The fatty acid composition in January was significantly different from all the other sampling months. The dissimilarities were mainly explained by changes in the relative abundance of 20:5n-3 (13.12%–33.35%), 14:0 (11.07%–29.37%) and 18:1n-9 (10.15%–16.94%). Polyunsaturated fatty acids (PUFA’s) made up more than half of the fatty acids with a maximum in July (52.3%–54.0% fatty acid methyl esters; FAME). This including the most appreciated health beneficial PUFA’s, eicosapentaenoic (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3), but also arachidonic (ARA) and stearidonic acid (SDA), which are not found in land vegetables such as cabbage and lettuce. Compared to fat (salmon) and lean fish (cod) this seaweed species contains higher proportions of ARA and SDA, but lower EPA (only cod) and DHA. Conclusively, the season of harvest is important for the choice of lipid quantity and quality, but the marine vegetables provide better sources of EPA, DHA and long-chain (LC)-PUFA’s in general compared to traditional vegetables. Full article

(This article belongs to the Special Issue Marine Lipids)

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Open AccessCommunication

New α-Glucosidase Inhibitory Triterpenic Acid from Marine Macro Green Alga Codium dwarkense Boergs

by Liaqat Ali, Abdul Latif Khan, Lubna Al-Kharusi, Javid Hussain and Ahmed Al-Harrasi

Mar. Drugs 2015, 13(7), 4344-4356; https://doi.org/10.3390/md13074344 - 14 Jul 2015

Cited by 19 | Viewed by 7593

Abstract

The marine ecosystem has been a key resource for secondary metabolites with promising biological roles. In the current study, bioassay-guided phytochemical investigations were carried out to assess the presence of enzyme inhibitory chemical constituents from the methanolic extract of marine green alga—Codium [...] Read more.

The marine ecosystem has been a key resource for secondary metabolites with promising biological roles. In the current study, bioassay-guided phytochemical investigations were carried out to assess the presence of enzyme inhibitory chemical constituents from the methanolic extract of marine green alga—Codium dwarkense. The bioactive fractions were further subjected to chromatographic separations, which resulted in the isolation of a new triterpenic acid; dwarkenoic acid (1) and the known sterols; androst-5-en-3β-ol (2), stigmasta-5,25-dien-3β,7α-diol (3), ergosta-5,25-dien-3β-ol (4), 7-hydroxystigmasta-4,25-dien-3-one-7-O-β-d-fucopyranoside (5), 7-hydroxystigmasta-4,25-dien-3-one (6), and stigmasta-5,25-dien-3β-ol (7). The structure elucidation of the new compound was carried out by combined mass spectrometry and 1D (¹H and ¹³C) and 2D (HSQC, HMBC, COSY, and NOESY) NMR spectroscopic data. The sub-fractions and pure constituents were assayed for enzymatic inhibition of alpha-glucosidase. Compound 1 showed significant inhibition at all concentrations. Compounds 2, 3, 5, and 7 exhibited a dose-dependent response, whereas compounds 4–6 showed moderate inhibition. Utilizing such marine-derived biological resources could lead to drug discoveries related to anti-diabetics. Full article

(This article belongs to the Special Issue Marine Secondary Metabolites)

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Open AccessArticle

Identification of the Scopularide Biosynthetic Gene Cluster in Scopulariopsis brevicaulis

by Mie Bech Lukassen, Wagma Saei, Teis Esben Sondergaard, Anu Tamminen, Abhishek Kumar, Frank Kempken, Marilyn G. Wiebe and Jens Laurids Sørensen

Mar. Drugs 2015, 13(7), 4331-4343; https://doi.org/10.3390/md13074331 - 14 Jul 2015

Cited by 26 | Viewed by 9344

Abstract

Scopularide A is a promising potent anticancer lipopeptide isolated from a marine derived Scopulariopsis brevicaulis strain. The compound consists of a reduced carbon chain (3-hydroxy-methyldecanoyl) attached to five amino acids (glycine, l-valine, d-leucine, l-alanine, and l-phenylalanine). Using the newly sequenced S. brevicaulis genome [...] Read more.

Scopularide A is a promising potent anticancer lipopeptide isolated from a marine derived Scopulariopsis brevicaulis strain. The compound consists of a reduced carbon chain (3-hydroxy-methyldecanoyl) attached to five amino acids (glycine, l-valine, d-leucine, l-alanine, and l-phenylalanine). Using the newly sequenced S. brevicaulis genome we were able to identify the putative biosynthetic gene cluster using genetic information from the structurally related emericellamide A from Aspergillus nidulans and W493-B from Fusarium pseudograminearum. The scopularide A gene cluster includes a nonribosomal peptide synthetase (NRPS1), a polyketide synthase (PKS2), a CoA ligase, an acyltransferase, and a transcription factor. Homologous recombination was low in S. brevicaulis so the local transcription factor was integrated randomly under a constitutive promoter, which led to a three to four-fold increase in scopularide A production. This indirectly verifies the identity of the proposed biosynthetic gene cluster. Full article

(This article belongs to the Special Issue Bioactive Compounds from Marine Fungi)

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Open AccessReview

Multiple Mechanisms of Anti-Cancer Effects Exerted by Astaxanthin

by Li Zhang and Handong Wang

Mar. Drugs 2015, 13(7), 4310-4330; https://doi.org/10.3390/md13074310 - 14 Jul 2015

Cited by 147 | Viewed by 13625

Abstract

Astaxanthin (ATX) is a xanthophyll carotenoid which has been approved by the United States Food and Drug Administration (USFDA) as food colorant in animal and fish feed. It is widely found in algae and aquatic animals and has powerful anti-oxidative activity. Previous studies [...] Read more.

Astaxanthin (ATX) is a xanthophyll carotenoid which has been approved by the United States Food and Drug Administration (USFDA) as food colorant in animal and fish feed. It is widely found in algae and aquatic animals and has powerful anti-oxidative activity. Previous studies have revealed that ATX, with its anti-oxidative property, is beneficial as a therapeutic agent for various diseases without any side effects or toxicity. In addition, ATX also shows preclinical anti-tumor efficacy both in vivo and in vitro in various cancer models. Several researches have deciphered that ATX exerts its anti-proliferative, anti-apoptosis and anti-invasion influence via different molecules and pathways including signal transducer and activator of transcription 3 (STAT3), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and peroxisome proliferator-activated receptor gamma (PPARγ). Hence, ATX shows great promise as chemotherapeutic agents in cancer. Here, we review the rapidly advancing field of ATX in cancer therapy as well as some molecular targets of ATX. Full article

(This article belongs to the Special Issue Marine Carotenoids and Oxidative Stress)

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Open AccessArticle

New Scalarane Sesterterpenoids from the Formosan Sponge Ircinia felix

by Ya-Yuan Lai, Mei-Chin Lu, Li-Hsueh Wang, Jih-Jung Chen, Lee-Shing Fang, Yang-Chang Wu and Ping-Jyun Sung

Mar. Drugs 2015, 13(7), 4296-4309; https://doi.org/10.3390/md13074296 - 14 Jul 2015

Cited by 21 | Viewed by 5576

Abstract

Five new scalarane sesterterpenoids, felixins A–E (1–5), were isolated from the Formosan sponge Ircinia felix. The structures of scalaranes 1–5 were elucidated on the basis of spectroscopic analysis. Cytotoxicity of scalaranes 1–5 against the [...] Read more.

Five new scalarane sesterterpenoids, felixins A–E (1–5), were isolated from the Formosan sponge Ircinia felix. The structures of scalaranes 1–5 were elucidated on the basis of spectroscopic analysis. Cytotoxicity of scalaranes 1–5 against the proliferation of a limited panel of tumor cell lines was evaluated. Full article

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Open AccessArticle

Distribution of Marine Lipophilic Toxins in Shellfish Products Collected from the Chinese Market

by Haiyan Wu, Jianhua Yao, Mengmeng Guo, Zhijun Tan, Deqing Zhou and Yuxiu Zhai

Mar. Drugs 2015, 13(7), 4281-4295; https://doi.org/10.3390/md13074281 - 14 Jul 2015

Cited by 36 | Viewed by 8826

Abstract

To investigate the prevalence of lipophilic marine biotoxins in shellfish from the Chinese market, we used hydrophilic interaction liquid chromatography-tandem mass spectrometry (LC-MS/MS) to measure levels of okadaic acid (OA), azaspiracid (AZA1), pectenotoxin (PTX2), gymnodimine (GYM), and spirolide (SPX1). We collected and analyzed [...] Read more.

To investigate the prevalence of lipophilic marine biotoxins in shellfish from the Chinese market, we used hydrophilic interaction liquid chromatography-tandem mass spectrometry (LC-MS/MS) to measure levels of okadaic acid (OA), azaspiracid (AZA1), pectenotoxin (PTX2), gymnodimine (GYM), and spirolide (SPX1). We collected and analyzed 291 shellfish samples from main production sites along a wide latitudinal transect along the Chinese coastline from December 2008 to December 2009. Results revealed a patchy distribution of the five toxins and highlighted the specific geographical distribution and seasonal and species variation of the putative toxigenic organisms. All five lipophilic marine biotoxins were found in shellfish samples. The highest concentrations of OA, AZA1, PTX2, GYM, and SPX1 were 37.3, 5.90, 16.4, 14.4, and 8.97 μg/kg, respectively. These values were much lower than the legislation limits for lipophilic shellfish toxins. However, the value might be significantly underestimated for the limited detection toxins. Also, these toxins were found in most coastal areas of China and were present in almost all seasons of the year. Thus, these five toxins represent a potential threat to human health. Consequently, studies should be conducted and measures should be taken to ensure the safety of the harvested product. Full article

(This article belongs to the Special Issue Okadaic Acid and Dinophysis Toxins)

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Open AccessArticle

Laminarin from Irish Brown Seaweeds Ascophyllum nodosum and Laminaria hyperborea: Ultrasound Assisted Extraction, Characterization and Bioactivity

by Shekhar U. Kadam, Colm P. O'Donnell, Dilip K. Rai, Mohammad B. Hossain, Catherine M. Burgess, Des Walsh and Brijesh K. Tiwari

Mar. Drugs 2015, 13(7), 4270-4280; https://doi.org/10.3390/md13074270 - 10 Jul 2015

Cited by 224 | Viewed by 13597

Abstract

Ultrasound assisted extraction (UAE), purification, characterization and antioxidant activity of laminarin from Irish brown seaweeds Ascophyllum nodosum and Laminarina hyperborea were investigated. UAE was carried out using 60% ultrasonic power amplitude and 0.1 M hydrochloric acid for 15 min. Separately, solid-liquid extraction was [...] Read more.

Ultrasound assisted extraction (UAE), purification, characterization and antioxidant activity of laminarin from Irish brown seaweeds Ascophyllum nodosum and Laminarina hyperborea were investigated. UAE was carried out using 60% ultrasonic power amplitude and 0.1 M hydrochloric acid for 15 min. Separately, solid-liquid extraction was carried in an orbital shaker using 0.1 M hydrochloric acid at 70 °C for 2.5 h. UAE with hydrochloric acid resulted in the highest concentration of laminarin, 5.82% and 6.24% on dry weight basis from A. nodosum and L. hyperborea, respectively. Purification of all extracts was carried out using molecular weight cut off dialysis at 10 kDa. Characterization of the laminarin fraction was carried out using matrix assisted laser desorption/ionization time-of-flight mass spectrometry. Antioxidant activity of A. nodosum and L. hyperborea extracts had 2,2-diphenyl-1-picrylhydrazyl (DPPH) inhibition levels of 93.23% and 87.57%, respectively. Moreover, these extracts have shown inihibition of bacterial growth of Staphylcoccus aureus, Listeria monocytogenes, Escherichia coli and Salmonella typhimurium. Full article

(This article belongs to the Collection Marine Polysaccharides)

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Open AccessArticle

Positional Distribution of Fatty Acids in Triacylglycerols and Phospholipids from Fillets of Atlantic Salmon (Salmo Salar) Fed Vegetable and Fish Oil Blends

by Noemi Ruiz-Lopez, Ingunn Stubhaug, Ignacio Ipharraguerre, Gerald Rimbach and David Menoyo

Mar. Drugs 2015, 13(7), 4255-4269; https://doi.org/10.3390/md13074255 - 10 Jul 2015

Cited by 46 | Viewed by 7605

Abstract

The nutritional and functional characteristics of dietary fat are related to the fatty acid (FA) composition and its positional distribution in the triacylglycerol (TAG) fraction. Atlantic salmon is an important source of healthy long chain omega 3 FA (particularly, eicosapentaenoic (EPA) and docoxahexaenoic [...] Read more.

The nutritional and functional characteristics of dietary fat are related to the fatty acid (FA) composition and its positional distribution in the triacylglycerol (TAG) fraction. Atlantic salmon is an important source of healthy long chain omega 3 FA (particularly, eicosapentaenoic (EPA) and docoxahexaenoic (DHA) acids). However, the impact of lipid sources in salmon feeds on the regiospecificity of FA in the fish TAG remains to be explored. The present study determines the effect of feeding salmon with blends of palm, rapeseed, and fish oil, providing two different EPA + DHA concentrations (high: H-ED 10.3% and low: L-ED 4.6%) on the fillet lipid class composition and the positional distribution of FA in TAG and phospholipids. The regiospecific analysis of fillet TAG showed that around 50% of the EPA and around 80% of DHA was located in the sn-2 position. The positional distribution of FA in phosphatidylcholine (PC), showed that around 80% of the EPA and around 90% of DHA were located in the sn-2. Fish fed the vegetable-rich diets showed higher EPA in the sn-2 position in PC (77% vs. 83% in the H-ED and L-ED diets, respectively) but similar DHA concentrations. It is concluded that feeding salmon with different EPA + DHA concentrations does not affect their positional distribution in the fillet TAG. Full article

(This article belongs to the Special Issue Marine Lipids)

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348 KiB

Open AccessReview

Advances in Microalgae-Derived Phytosterols for Functional Food and Pharmaceutical Applications

by Xuan Luo, Peng Su and Wei Zhang

Mar. Drugs 2015, 13(7), 4231-4254; https://doi.org/10.3390/md13074231 - 9 Jul 2015

Cited by 170 | Viewed by 13248

Abstract

Microalgae contain a variety of bioactive lipids with potential applications in aquaculture feed, biofuel, food and pharmaceutical industries. While microalgae-derived polyunsaturated fatty acid (PUFA) and their roles in promoting human health have been extensively studied, other lipid types from this resource, such as [...] Read more.

Microalgae contain a variety of bioactive lipids with potential applications in aquaculture feed, biofuel, food and pharmaceutical industries. While microalgae-derived polyunsaturated fatty acid (PUFA) and their roles in promoting human health have been extensively studied, other lipid types from this resource, such as phytosterols, have been poorly explored. Phytosterols have been used as additives in many food products such as spread, dairy products and salad dressing. This review focuses on the recent advances in microalgae-derived phytosterols with functional bioactivities and their potential applications in functional food and pharmaceutical industries. It highlights the importance of microalgae-derived lipids other than PUFA for the development of an advanced microalgae industry. Full article

(This article belongs to the Special Issue Marine Lipids)

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Open AccessReview

Structure and Effects of Cyanobacterial Lipopolysaccharides

by Prasannavenkatesh Durai, Maria Batool and Sangdun Choi

Mar. Drugs 2015, 13(7), 4217-4230; https://doi.org/10.3390/md13074217 - 7 Jul 2015

Cited by 62 | Viewed by 9037

Abstract

Lipopolysaccharide (LPS) is a component of the outer membrane of mainly Gram-negative bacteria and cyanobacteria. The LPS molecules from marine and terrestrial bacteria show structural variations, even among strains within the same species living in the same environment. Cyanobacterial LPS has a unique [...] Read more.

Lipopolysaccharide (LPS) is a component of the outer membrane of mainly Gram-negative bacteria and cyanobacteria. The LPS molecules from marine and terrestrial bacteria show structural variations, even among strains within the same species living in the same environment. Cyanobacterial LPS has a unique structure, since it lacks heptose and 3-deoxy-d-manno-octulosonic acid (also known as keto-deoxyoctulosonate (KDO)), which are present in the core region of common Gram-negative LPS. In addition, the cyanobacterial lipid A region lacks phosphates and contains odd-chain hydroxylated fatty acids. While the role of Gram-negative lipid A in the regulation of the innate immune response through Toll-like Receptor (TLR) 4 signaling is well characterized, the role of the structurally different cyanobacterial lipid A in TLR4 signaling is not well understood. The uncontrolled inflammatory response of TLR4 leads to autoimmune diseases such as sepsis, and thus the less virulent marine cyanobacterial LPS molecules can be effective to inhibit TLR4 signaling. This review highlights the structural comparison of LPS molecules from marine cyanobacteria and Gram-negative bacteria. We discuss the potential use of marine cyanobacterial LPS as a TLR4 antagonist, and the effects of cyanobacterial LPS on humans and marine organisms. Full article

(This article belongs to the Special Issue Marine Lipopolysaccharides)

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Open AccessArticle

Red Algae (Rhodophyta) from the Coast of Madagascar: Preliminary Bioactivity Studies and Isolation of Natural Products

by Marie Pascaline Rahelivao, Margit Gruner, Hanta Andriamanantoanina, Bakolinirina Andriamihaja, Ingmar Bauer and Hans-Joachim Knölker

Mar. Drugs 2015, 13(7), 4197-4216; https://doi.org/10.3390/md13074197 - 7 Jul 2015

Cited by 38 | Viewed by 8592

Abstract

Several species of red algae (Rhodophyta) from the coastal regions of Madagascar have been investigated for their natural products. The most abundant compound was cholesterol (5) in combination with a series of oxidized congeners. The brominated indoles 1–3 along [...] Read more.

Several species of red algae (Rhodophyta) from the coastal regions of Madagascar have been investigated for their natural products. The most abundant compound was cholesterol (5) in combination with a series of oxidized congeners. The brominated indoles 1–3 along with the sesquiterpene debilone (4) have been isolated from Laurencia complanata. For the first time, debilone (4) has been obtained from a marine plant. From the methanol extract of Calloseris sp., we have achieved the second isolation of the unusual A-ring contracted steroids (−)-2-ethoxycarbonyl-2β-hydroxy-A-nor-cholest-5-en-4-one (9) and phorbasterone B (10). The crude extracts of Laurencia complanata exhibited antimicrobial activity against Bacillus cereus, Staphylococcus aureus, Streptococcus pneumoniae, and Candida albicans. Full article

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Open AccessArticle

Functional and Structural Characterization of FAU Gene/Protein from Marine Sponge Suberites domuncula

by Dragutin Perina, Marina Korolija, Marijana Popović Hadžija, Ivana Grbeša, Robert Belužić, Mirna Imešek, Christine Morrow, Melanija Posavec Marjanović, Tatjana Bakran-Petricioli, Andreja Mikoč and Helena Ćetković

Mar. Drugs 2015, 13(7), 4179-4196; https://doi.org/10.3390/md13074179 - 7 Jul 2015

Cited by 10 | Viewed by 6869

Abstract

Finkel-Biskis-Reilly murine sarcoma virus (FBR-MuSV) ubiquitously expressed (FAU) gene is down-regulated in human prostate, breast and ovarian cancers. Moreover, its dysregulation is associated with poor prognosis in breast cancer. Sponges (Porifera) are animals without tissues which branched off first from the [...] Read more.

Finkel-Biskis-Reilly murine sarcoma virus (FBR-MuSV) ubiquitously expressed (FAU) gene is down-regulated in human prostate, breast and ovarian cancers. Moreover, its dysregulation is associated with poor prognosis in breast cancer. Sponges (Porifera) are animals without tissues which branched off first from the common ancestor of all metazoans. A large majority of genes implicated in human cancers have their homologues in the sponge genome. Our study suggests that FAU gene from the sponge Suberites domuncula reflects characteristics of the FAU gene from the metazoan ancestor, which have changed only slightly during the course of animal evolution. We found pro-apoptotic activity of sponge FAU protein. The same as its human homologue, sponge FAU increases apoptosis in human HEK293T cells. This indicates that the biological functions of FAU, usually associated with “higher” metazoans, particularly in cancer etiology, possess a biochemical background established early in metazoan evolution. The ancestor of all animals possibly possessed FAU protein with the structure and function similar to evolutionarily more recent versions of the protein, even before the appearance of true tissues and the origin of tumors and metastasis. It provides an opportunity to use pre-bilaterian animals as a simpler model for studying complex interactions in human cancerogenesis. Full article

(This article belongs to the Collection Marine Compounds and Cancer)

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Open AccessCommunication

Bioactive 7-Oxabicyclic[6.3.0]lactam and 12-Membered Macrolides from a Gorgonian-Derived Cladosporium sp. Fungus

by Fei Cao, Qin Yang, Chang-Lun Shao, Chui-Jian Kong, Juan-Juan Zheng, Yun-Feng Liu and Chang-Yun Wang

Mar. Drugs 2015, 13(7), 4171-4178; https://doi.org/10.3390/md13074171 - 7 Jul 2015

Cited by 36 | Viewed by 6716

Abstract

One new bicyclic lactam, cladosporilactam A (1), and six known 12-membered macrolides (2–7) were isolated from a gorgonian-derived Cladosporium sp. fungus collected from the South China Sea. Their complete structural assignments were elucidated by comprehensive spectroscopic investigation. [...] Read more.

One new bicyclic lactam, cladosporilactam A (1), and six known 12-membered macrolides (2–7) were isolated from a gorgonian-derived Cladosporium sp. fungus collected from the South China Sea. Their complete structural assignments were elucidated by comprehensive spectroscopic investigation. Quantum chemistry calculations were used in support of the structural determination of 1. The absolute configuration of 1 was determined by calculation of its optical rotation. Cladosporilactam A (1) was the first example of 7-oxabicyclic[6.3.0]lactam obtained from a natural source. Compound 1 exhibited promising cytotoxic activity against cervical cancer HeLa cell line with an IC₅₀ value of 0.76 μM. Full article

(This article belongs to the Special Issue Bioactive Compounds from Marine Fungi)

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Open AccessArticle

Fucoidan Stimulates Monocyte Migration via ERK/p38 Signaling Pathways and MMP9 Secretion

by Elene Sapharikas, Anna Lokajczyk, Anne-Marie Fischer and Catherine Boisson-Vidal

Mar. Drugs 2015, 13(7), 4156-4170; https://doi.org/10.3390/md13074156 - 30 Jun 2015

Cited by 18 | Viewed by 7970

Abstract

Critical limb ischemia (CLI) induces the secretion of paracrine signals, leading to monocyte recruitment and thereby contributing to the initiation of angiogenesis and tissue healing. We have previously demonstrated that fucoidan, an antithrombotic polysaccharide, promotes the formation of new blood vessels in a [...] Read more.

Critical limb ischemia (CLI) induces the secretion of paracrine signals, leading to monocyte recruitment and thereby contributing to the initiation of angiogenesis and tissue healing. We have previously demonstrated that fucoidan, an antithrombotic polysaccharide, promotes the formation of new blood vessels in a mouse model of hindlimb ischemia. We examined the effect of fucoidan on the capacity of peripheral blood monocytes to adhere and migrate. Monocytes negatively isolated with magnetic beads from peripheral blood of healthy donors were treated with fucoidan. Fucoidan induced a 1.5-fold increase in monocyte adhesion to gelatin (p < 0.05) and a five-fold increase in chemotaxis in Boyden chambers (p < 0.05). Fucoidan also enhanced migration 2.5-fold in a transmigration assay (p < 0.05). MMP9 activity in monocyte supernatants was significantly enhanced by fucoidan (p < 0.05). Finally, Western blot analysis of fucoidan-treated monocytes showed upregulation of ERK/p38 phosphorylation. Inhibition of ERK/p38 phosphorylation abrogated fucoidan enhancement of migration (p < 0.01). Fucoidan displays striking biological effects, notably promoting monocyte adhesion and migration. These effects involve the ERK and p38 pathways, and increased MMP9 activity. Fucoidan could improve critical limb ischemia by promoting monocyte recruitment. Full article

(This article belongs to the Collection Marine Polysaccharides)

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Open AccessArticle

Investigation of Marine-Derived Fungal Diversity and Their Exploitable Biological Activities

by Joo-Hyun Hong, Seokyoon Jang, Young Mok Heo, Mihee Min, Hwanhwi Lee, Young Min Lee, Hanbyul Lee and Jae-Jin Kim

Mar. Drugs 2015, 13(7), 4137-4155; https://doi.org/10.3390/md13074137 - 30 Jun 2015

Cited by 74 | Viewed by 8160

Abstract

Marine fungi are potential producers of bioactive compounds that may have pharmacological and medicinal applications. Fungi were cultured from marine brown algae and identified using multiple target genes to confirm phylogenetic placement. These target genes included the internal transcribed spacer (ITS), the nuclear [...] Read more.

Marine fungi are potential producers of bioactive compounds that may have pharmacological and medicinal applications. Fungi were cultured from marine brown algae and identified using multiple target genes to confirm phylogenetic placement. These target genes included the internal transcribed spacer (ITS), the nuclear large subunit (LSU), and the β-tubulin region. Various biological activities of marine-derived fungi were evaluated, including their antifungal, antioxidant and cellulolytic enzyme activities. As a result, a total of 50 fungi was isolated from the brown algae Sargassum sp. Among the 50 isolated fungi, Corollospora angusta was the dominant species in this study. The genus Arthrinium showed a relatively strong antifungal activity to all of the target plant pathogenic fungi. In particular, Arthrinium saccharicola KUC21221 showed high radical scavenging activity and the highest activities in terms of filter paper units (0.39 U/mL), endoglucanase activity (0.38 U/mL), and β-glucosidase activity (1.04 U/mL). Full article

(This article belongs to the Special Issue Bioactive Compounds from Marine Fungi)

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Open AccessReview

Biological Activity of Recently Discovered Halogenated Marine Natural Products

by Gordon W. Gribble

Mar. Drugs 2015, 13(7), 4044-4136; https://doi.org/10.3390/md13074044 - 30 Jun 2015

Cited by 212 | Viewed by 17626

Abstract

This review presents the biological activity—antibacterial, antifungal, anti-parasitic, antiviral, antitumor, antiinflammatory, antioxidant, and enzymatic activity—of halogenated marine natural products discovered in the past five years. Newly discovered examples that do not report biological activity are not included. Full article

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Open AccessReview

Marine Peptides: Bioactivities and Applications

by Randy Chi Fai Cheung, Tzi Bun Ng and Jack Ho Wong

Mar. Drugs 2015, 13(7), 4006-4043; https://doi.org/10.3390/md13074006 - 29 Jun 2015

Cited by 304 | Viewed by 18917

Abstract

Peptides are important bioactive natural products which are present in many marine species. These marine peptides have high potential nutraceutical and medicinal values because of their broad spectra of bioactivities. Their antimicrobial, antiviral, antitumor, antioxidative, cardioprotective (antihypertensive, antiatherosclerotic and anticoagulant), immunomodulatory, analgesic, anxiolytic [...] Read more.

Peptides are important bioactive natural products which are present in many marine species. These marine peptides have high potential nutraceutical and medicinal values because of their broad spectra of bioactivities. Their antimicrobial, antiviral, antitumor, antioxidative, cardioprotective (antihypertensive, antiatherosclerotic and anticoagulant), immunomodulatory, analgesic, anxiolytic anti-diabetic, appetite suppressing and neuroprotective activities have attracted the attention of the pharmaceutical industry, which attempts to design them for use in the treatment or prevention of various diseases. Some marine peptides or their derivatives have high commercial values and had reached the pharmaceutical and nutraceutical markets. A large number of them are already in different phases of the clinical and preclinical pipeline. This review highlights the recent research in marine peptides and the trends and prospects for the future, with special emphasis on nutraceutical and pharmaceutical development into marketed products. Full article

(This article belongs to the Special Issue Marine Peptides and Their Mimetics)

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Open AccessArticle

Production of Calcaride A by Calcarisporium sp. in Shaken Flasks and Stirred Bioreactors

by Anu Tamminen, Yanming Wang and Marilyn G. Wiebe

Mar. Drugs 2015, 13(7), 3992-4005; https://doi.org/10.3390/md13073992 - 24 Jun 2015

Cited by 4 | Viewed by 6519

Abstract

Increased interest in marine resources has led to increased screening of marine fungi for novel bioactive compounds and considerable effort is being invested in discovering these metabolites. For compound discovery, small-scale cultures are adequate, but agitated bioreactors are desirable for larger-scale production. Calcarisporium [...] Read more.

Increased interest in marine resources has led to increased screening of marine fungi for novel bioactive compounds and considerable effort is being invested in discovering these metabolites. For compound discovery, small-scale cultures are adequate, but agitated bioreactors are desirable for larger-scale production. Calcarisporium sp. KF525 has recently been described to produce calcaride A, a cyclic polyester with antibiotic activity, in agitated flasks. Here, we describe improvements in the production of calcaride A in both flasks (13-fold improvement) and stirred bioreactors (200-fold improvement). Production of calcaride A in bioreactors was initially substantially lower than in shaken flasks. The cultivation pH (reduced from 6.8 to <5.4), carbon source (sucrose replacing glucose), C/N ratio and nature of mycelial growth (pellets or filaments) were important in improving calcaride A production. Up to 4.5 mg·g⁻¹ biomass (85 mg·L⁻¹) calcaride A were produced in the bioreactor, which was only slightly less than in shaken flasks (14 mg·g⁻¹, 100 mg·L⁻¹). The results demonstrate that a scalable process for calcaride A production could be developed using an iterative approach with flasks and bioreactors. Full article

(This article belongs to the Special Issue Bioactive Compounds from Marine Fungi)

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Mar. Drugs, Volume 13, Issue 7 (July 2015) – 29 articles , Pages 3992-4575

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