Marine Drugs

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Open AccessArticle

High-Throughput Identification of Antimicrobial Peptides from Amphibious Mudskippers

by Yunhai Yi, Xinxin You, Chao Bian, Shixi Chen, Zhao Lv, Limei Qiu and Qiong Shi

Mar. Drugs 2017, 15(11), 364; https://doi.org/10.3390/md15110364 - 22 Nov 2017

Cited by 30 | Viewed by 5297

Widespread existence of antimicrobial peptides (AMPs) has been reported in various animals with comprehensive biological activities, which is consistent with the important roles of AMPs as the first line of host defense system. However, no big-data-based analysis on AMPs from any fish species [...] Read more.

Widespread existence of antimicrobial peptides (AMPs) has been reported in various animals with comprehensive biological activities, which is consistent with the important roles of AMPs as the first line of host defense system. However, no big-data-based analysis on AMPs from any fish species is available. In this study, we identified 507 AMP transcripts on the basis of our previously reported genomes and transcriptomes of two representative amphibious mudskippers, Boleophthalmus pectinirostris (BP) and Periophthalmus magnuspinnatus (PM). The former is predominantly aquatic with less time out of water, while the latter is primarily terrestrial with extended periods of time on land. Within these identified AMPs, 449 sequences are novel; 15 were reported in BP previously; 48 are identically overlapped between BP and PM; 94 were validated by mass spectrometry. Moreover, most AMPs presented differential tissue transcription patterns in the two mudskippers. Interestingly, we discovered two AMPs, hemoglobin β1 and amylin, with high inhibitions on Micrococcus luteus. In conclusion, our high-throughput screening strategy based on genomic and transcriptomic data opens an efficient pathway to discover new antimicrobial peptides for ongoing development of marine drugs. Full article

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Open AccessShort Note

Aspersymmetide A, a New Centrosymmetric Cyclohexapeptide from the Marine-Derived Fungus Aspergillus versicolor

by Xue-Mei Hou, Ya-Hui Zhang, Yang Hai, Ji-Yong Zheng, Yu-Cheng Gu, Chang-Yun Wang and Chang-Lun Shao

Mar. Drugs 2017, 15(11), 363; https://doi.org/10.3390/md15110363 - 22 Nov 2017

Cited by 29 | Viewed by 4650

Abstract

A new centrosymmetric cyclohexapeptide, aspersymmetide A (1), together with a known peptide, asperphenamate (2), was isolated from the fungus Aspergillus versicolor isolated from a gorgonian coral Carijoa sp., collected from the South China Sea. The chemical structure of 1 [...] Read more.

A new centrosymmetric cyclohexapeptide, aspersymmetide A (1), together with a known peptide, asperphenamate (2), was isolated from the fungus Aspergillus versicolor isolated from a gorgonian coral Carijoa sp., collected from the South China Sea. The chemical structure of 1 was elucidated by analyzing its NMR spectroscopy and MS spectrometry data, and the absolute configurations of the amino acids of 1 were determined by Marfey’s method and UPLC-MS analysis of the hydrolysate. Aspersymmetide A (1) represents the first example of marine-derived centrosymmetric cyclohexapeptide. Moreover, 1 exhibited weak cytotoxicity against NCI-H292 and A431 cell lines at the concentration of 10 μM. Full article

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Open AccessArticle

Antimicrobial Peptide Epinecidin-1 Modulates MyD88 Protein Levels via the Proteasome Degradation Pathway

by Bor-Chyuan Su and Jyh-Yih Chen

Mar. Drugs 2017, 15(11), 362; https://doi.org/10.3390/md15110362 - 16 Nov 2017

Cited by 15 | Viewed by 6144

Abstract

The cationic antimicrobial peptide epinecidin-1 was identified from Epinephelus coioides and possesses multiple biological functions, including antibacterial, antifungal, anti-tumor, and immunomodulatory effects. In addition, epinecidin-1 suppresses lipopolysaccharide (LPS)-induced inflammation by neutralizing LPS and ameliorating LPS/Toll-like receptor (TLR)-4 internalization. However, it is unclear whether [...] Read more.

The cationic antimicrobial peptide epinecidin-1 was identified from Epinephelus coioides and possesses multiple biological functions, including antibacterial, antifungal, anti-tumor, and immunomodulatory effects. In addition, epinecidin-1 suppresses lipopolysaccharide (LPS)-induced inflammation by neutralizing LPS and ameliorating LPS/Toll-like receptor (TLR)-4 internalization. However, it is unclear whether the actions of epinecidin-1 depend on the regulation of TLR adaptor protein MyD88 or endogenous TLR signaling antagonists, which include A20, interleukin-1 receptor associated kinase (IRAK)-M, and suppressor of cytokine signaling (SOCS)-1. Our results demonstrate that epinecidin-1 alone does not affect A20, IRAK-M, or SOCS-1 protein levels. However, pre-incubation of epinecidin-1 significantly inhibits LPS-induced upregulation of A20, IRAK-M, and SOCS-1. In addition, epinecidin-1 significantly reduces the abundance of MyD88 protein. Both MG132 (a specific proteasome inhibitor) and Heclin (a specific Smurf E3 ligase inhibitor) are able to abolish epinecidin-1-mediated MyD88 degradation. Thus, our data suggest that epinecidin-1 directly inhibits MyD88 via induction of the Smurf E3 ligase proteasome pathway. Full article

(This article belongs to the Special Issue Marine Antimicrobial Agents)

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Open AccessFeature PaperReview

The Oxepane Motif in Marine Drugs

by Héctor Barbero, Carlos Díez-Poza and Asunción Barbero

Mar. Drugs 2017, 15(11), 361; https://doi.org/10.3390/md15110361 - 15 Nov 2017

Cited by 30 | Viewed by 9429

Abstract

Oceans have shown to be a remarkable source of natural products. The biological properties of many of these compounds have helped to produce great advances in medicinal chemistry. Within them, marine natural products containing an oxepanyl ring are present in a great variety [...] Read more.

Oceans have shown to be a remarkable source of natural products. The biological properties of many of these compounds have helped to produce great advances in medicinal chemistry. Within them, marine natural products containing an oxepanyl ring are present in a great variety of algae, sponges, fungus and corals and show very important biological activities, many of them possessing remarkable cytotoxic properties against a wide range of cancer cell lines. Their rich chemical structures have attracted the attention of many researchers who have reported interesting synthetic approaches to these targets. This review covers the most prominent examples of these types of compounds, focusing the discussion on the isolation, structure determination, medicinal properties and total synthesis of these products. Full article

(This article belongs to the Special Issue Bioactive Marine Natural Compounds with Heterocyclic Motifs in their Structure)

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Open AccessArticle

Proximate Composition and Nutritional Value of Three Macroalgae: Ascophyllum nodosum, Fucus vesiculosus and Bifurcaria bifurcata

by José M. Lorenzo, Rubén Agregán, Paulo E. S. Munekata, Daniel Franco, Javier Carballo, Selin Şahin, Ramón Lacomba and Francisco J. Barba

Mar. Drugs 2017, 15(11), 360; https://doi.org/10.3390/md15110360 - 15 Nov 2017

Cited by 146 | Viewed by 10616

Abstract

Proximate composition (moisture, protein, lipid and ash content) and nutritional value (fatty acid, amino acid and mineral profile) of three macroalgae (Ascophyllum nodosum, Fucus vesiculosus and Bifurcaria bifurcate) were studied. Chemical composition was significantly (p < 0.001) different among [...] Read more.

Proximate composition (moisture, protein, lipid and ash content) and nutritional value (fatty acid, amino acid and mineral profile) of three macroalgae (Ascophyllum nodosum, Fucus vesiculosus and Bifurcaria bifurcate) were studied. Chemical composition was significantly (p < 0.001) different among the three seaweeds. In this regard, the B. bifurcata presented the highest fat content (6.54% of dry matter); whereas, F. vesiculosus showed the highest protein level (12.99% dry matter). Regarding fatty acid content, the polyunsaturated fatty acids (PUFAs) were the most abundant followed by saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs). On the other hand, the three seaweeds are a rich source of K (from 3781.35 to 9316.28 mg/100 g), Mn (from 8.28 to 1.96 mg/100 g), Na (from 1836.82 to 4575.71 mg/100 g) and Ca (from 984.73 to 1160.27 mg/100 g). Finally, the most abundant amino acid was glutamic acid (1874.47–1504.53 mg/100 dry matter), followed by aspartic acid (1677.01–800.84 mg/100 g dry matter) and alanine (985.40–655.73 mg/100 g dry matter). Full article

(This article belongs to the Special Issue Marine Health Compounds: From Extraction to Food and Pharmaceutical Application)

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Open AccessArticle

Lactones from the Sponge-Derived Fungus Talaromyces rugulosus

by Lisa Küppers, Weaam Ebrahim, Mona El-Neketi, Ferhat C. Özkaya, Attila Mándi, Tibor Kurtán, Raha S. Orfali, Werner E. G. Müller, Rudolf Hartmann, Wenhan Lin, Weiguo Song, Zhen Liu and Peter Proksch

Mar. Drugs 2017, 15(11), 359; https://doi.org/10.3390/md15110359 - 14 Nov 2017

Cited by 33 | Viewed by 6539

Abstract

The marine-derived fungus Talaromyces rugulosus isolated from the Mediterranean sponge Axinella cannabina and cultured on solid rice medium yielded seventeen lactone derivatives including five butenolides (1–5), seven (3S)-resorcylide derivatives (6–12), two butenolide-resorcylide dimers [...] Read more.

The marine-derived fungus Talaromyces rugulosus isolated from the Mediterranean sponge Axinella cannabina and cultured on solid rice medium yielded seventeen lactone derivatives including five butenolides (1–5), seven (3S)-resorcylide derivatives (6–12), two butenolide-resorcylide dimers (13 and 14), and three dihydroisocoumarins (15–17). Among them, fourteen compounds (1–3, 6–16) are new natural products. The structures of the isolated compounds were elucidated by 1D and 2D NMR (Nuclear Magnetic Resonance) spectroscopy as well as by ESI-HRMS (ElectroSpray Ionization-High Resolution Mass Spectrometry). TDDFT-ECD (Time-Dependent Density Functional Theory-Electronic Circular Dichroism) calculations were performed to determine the absolute configurations of chiral compounds. The butenolide-resorcylide dimers talarodilactones A and B (13 and 14) exhibited potent cytotoxicity against the L5178Y murine lymphoma cell line with IC₅₀ values of 3.9 and 1.3 µM, respectively. Full article

(This article belongs to the Special Issue Bioactive Compounds from Marine Microbes - II)

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Open AccessArticle

Asperlin Inhibits LPS-Evoked Foam Cell Formation and Prevents Atherosclerosis in ApoE^−/− Mice

by Yue Zhou, Ran Chen, Dong Liu, Chongming Wu, Peng Guo and Wenhan Lin

Mar. Drugs 2017, 15(11), 358; https://doi.org/10.3390/md15110358 - 14 Nov 2017

Cited by 39 | Viewed by 5618

Abstract

Asperlin is a marine-derived natural product with antifungal and anti-inflammatory activities in vitro. In the present study, we isolated asperlin from a marine Aspergillus versicolor LZD4403 fungus and investigated its anti-atherosclerotic effects in vitro and in vivo. Asperlin significantly inhibited lipopolysaccharides (LPS)- but [...] Read more.

Asperlin is a marine-derived natural product with antifungal and anti-inflammatory activities in vitro. In the present study, we isolated asperlin from a marine Aspergillus versicolor LZD4403 fungus and investigated its anti-atherosclerotic effects in vitro and in vivo. Asperlin significantly inhibited lipopolysaccharides (LPS)- but not oxidated low-density lipoprotein (oxLDL)-evoked foam cell formation and promoted cholesterol efflux in RAW264.7 macrophages. Supplementation with asperlin also suppressed LPS-elicited production of pro-inflammatory factors in RAW264.7 macrophages, decreased the expression levels of iNOS, IL-1β and TNFα, and increased the expression of IL-10 and IL-4, indicating a remarkable shift in M1/M2 macrophages polarization. In vivo experiments in high-fat diet (HFD)-fed ApoE^−/− mice showed that oral administration of asperlin for 12 weeks remarkably suppressed atherosclerotic plaque formation in the aorta, as revealed by the reduced aortic dilatation and decreased atherosclerotic lesion area. Asperlin also decreased serum levels of pro-inflammatory factors but showed little impact on blood lipids in ApoE^−/− atherosclerotic mice. These results suggested that asperlin is adequate to prevent atherosclerosis in vivo. It may exert atheroprotective function through suppressing inflammation rather than ameliorating dyslipidemia. Full article

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Open AccessArticle

Physiological and Biochemical Changes Reveal Differential Patterns of Docosahexaenoic Acid Partitioning in Two Marine Algal Strains of Isochrysis

by Zheng Sun, Yong Chen, Xuemei Mao and Jin Liu

Mar. Drugs 2017, 15(11), 357; https://doi.org/10.3390/md15110357 - 12 Nov 2017

Cited by 6 | Viewed by 4209

Abstract

The marine microalgae Isochrysis are a good producer of natural docosahexaenoic acid (DHA). To better understand the patterns of DHA accumulation and distribution, two Isochrysis strains, CL153180 and CCMP462, were evaluated in this study. In a batch culture, CL153180 showed a decline in [...] Read more.

The marine microalgae Isochrysis are a good producer of natural docosahexaenoic acid (DHA). To better understand the patterns of DHA accumulation and distribution, two Isochrysis strains, CL153180 and CCMP462, were evaluated in this study. In a batch culture, CL153180 showed a decline in DHA content while CCMP462 exhibited a progressive increase during the late growth period when nitrogen was almost exhausted. In response to nitrogen deficiency (ND), both strains showed a considerable increase in neutral lipids (NL) at the expense of glycolipids (GL) but had little variation in phospholipids (PL). In CL153180, the DHA percentage of NL decreased gradually upon ND, while that in CCMP462 increased progressively to 21.4% after 4 days of ND, which is around 5-fold higher than CL153180. Accordingly, in contrast to CL153180 that stored DHA predominantly in GL, CCMP462 accumulated DHA mainly in NL in late days of ND. Taken together, we proposed a working model for the differential DHA partitioning patterns between two Isochrysis strains: for CCMP462, the degradation of GL released free fatty acids including DHA, which was incorporated into NL upon ND; whereas for CL153180, the released DHA from GL might not be incorporated into NL, and, consequently, might be subject to β-oxidation for degradation. Full article

(This article belongs to the Collection Bioactive Compounds from Marine Plankton)

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Open AccessFeature PaperArticle

New 2-Methoxy Acetylenic Acids and Pyrazole Alkaloids from the Marine Sponge Cinachyrella sp.

by Amin Mokhlesi, Rudolf Hartmann, Tibor Kurtán, Horst Weber, Wenhan Lin, Chaidir Chaidir, Werner E. G. Müller, Georgios Daletos and Peter Proksch

Mar. Drugs 2017, 15(11), 356; https://doi.org/10.3390/md15110356 - 11 Nov 2017

Cited by 14 | Viewed by 5100

Abstract

Three new 2-methoxy acetylenic acids (1–3) and a known derivative (4), in addition to three new natural pyrazole alkaloids (5–7) were isolated from an Indonesian marine sponge of the genus Cinachyrella. Compounds 5 and 6 have previously been reported as synthetic compounds. The [...] Read more.

Three new 2-methoxy acetylenic acids (1–3) and a known derivative (4), in addition to three new natural pyrazole alkaloids (5–7) were isolated from an Indonesian marine sponge of the genus Cinachyrella. Compounds 5 and 6 have previously been reported as synthetic compounds. The structures of the new compounds were established on the basis of one- and two-dimensional NMR spectroscopy as well as by mass spectrometric data. The absolute configuration of the new acetylenic acid derivatives (1–3) was established by ECD spectroscopy. All isolated compounds were evaluated for their cytotoxicity against L5178Y mouse lymphoma cells. Compounds 1–4 exhibited strong activity with an IC50 value of 0.3 µM. A plausible biosynthetic pathway for the pyrazole metabolites 5–7 is proposed. Full article

(This article belongs to the Collection Bioactive Compounds from Marine Invertebrates)

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Open AccessArticle

Anandins A and B, Two Rare Steroidal Alkaloids from a Marine Streptomyces anandii H41-59

by Yang-Mei Zhang, Bai-Lian Liu, Xin-Heng Zheng, Xiao-Jun Huang, Hong-Yu Li, Ying Zhang, Ting-Ting Zhang, Da-Yuan Sun, Bi-Run Lin and Guang-Xiong Zhou

Mar. Drugs 2017, 15(11), 355; https://doi.org/10.3390/md15110355 - 10 Nov 2017

Cited by 18 | Viewed by 4430

Abstract

Anandins A (1) and B (2), two rare steroidal alkaloids, were isolated from the fermentative broth of a marine actinobacteria Streptomyces anandii H41-59. The gross structures of the two alkaloids were elucidated by spectroscopic methods including HR-ESI-MS, and NMR. [...] Read more.

Anandins A (1) and B (2), two rare steroidal alkaloids, were isolated from the fermentative broth of a marine actinobacteria Streptomyces anandii H41-59. The gross structures of the two alkaloids were elucidated by spectroscopic methods including HR-ESI-MS, and NMR. Their absolute configurations were confirmed by single-crystal X-ray diffraction analysis and comparison of their experimental and calculated electronic circular dichroism spectra, respectively. Anandin A exhibited a moderate inhibitory effect against three human cancer cell lines MCF-7, SF-268, and NCI-H460 with IC₅₀ values of 7.5, 7.9, 7.8 μg/mL, respectively. Full article

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Open AccessReview

Structural Diversity, Biological Properties and Applications of Natural Products from Cyanobacteria. A Review

by Sayed Asmat Ali Shah, Najeeb Akhter, Bibi Nazia Auckloo, Ishrat Khan, Yanbin Lu, Kuiwu Wang, Bin Wu and Yue-Wei Guo

Mar. Drugs 2017, 15(11), 354; https://doi.org/10.3390/md15110354 - 10 Nov 2017

Cited by 83 | Viewed by 10245

Abstract

Nowadays, various drugs on the market are becoming more and more resistant to numerous diseases, thus declining their efficacy for treatment purposes in human beings. Antibiotic resistance is one among the top listed threat around the world which eventually urged the discovery of [...] Read more.

Nowadays, various drugs on the market are becoming more and more resistant to numerous diseases, thus declining their efficacy for treatment purposes in human beings. Antibiotic resistance is one among the top listed threat around the world which eventually urged the discovery of new potent drugs followed by an increase in the number of deaths caused by cancer due to chemotherapy resistance as well. Accordingly, marine cyanobacteria, being the oldest prokaryotic microorganisms belonging to a monophyletic group, have proven themselves as being able to generate pharmaceutically important natural products. They have long been known to produce distinct and structurally complex secondary metabolites including peptides, polyketides, alkaloids, lipids, and terpenes with potent biological properties and applications. As such, this review will focus on recently published novel compounds isolated from marine cyanobacteria along with their potential bioactivities such as antibacterial, antifungal, anticancer, anti-tuberculosis, immunosuppressive and anti-inflammatory capacities. Moreover, various structural classes, as well as their technological uses will also be discussed. Full article

(This article belongs to the Special Issue From Bioactive Compounds to New Drugs: Commemorative Issue Dedicated to Professor Ernesto Fattorusso (1937-2012))

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Open AccessArticle

An Insight into Sargassum muticum Cytoprotective Mechanisms against Oxidative Stress on a Human Cell In Vitro Model

by Susete Pinteus, Marco F. L. Lemos, Joana Silva, Celso Alves, Agnieszka Neugebauer, Rafaela Freitas, Adriana Duarte and Rui Pedrosa

Mar. Drugs 2017, 15(11), 353; https://doi.org/10.3390/md15110353 - 10 Nov 2017

Cited by 14 | Viewed by 5404

Abstract

Sargassum muticum is a brown seaweed with strong potential to be used as a functional food ingredient, mainly due to its antioxidant properties. It is widely used in traditional oriental medicine for the treatment of numerous diseases. Nevertheless, few studies have been conducted [...] Read more.

Sargassum muticum is a brown seaweed with strong potential to be used as a functional food ingredient, mainly due to its antioxidant properties. It is widely used in traditional oriental medicine for the treatment of numerous diseases. Nevertheless, few studies have been conducted to add scientific evidence on its effects as well as on the mechanisms of action involved. In this work, the human cell line MCF-7 was used as an in vitro cellular model to evaluate the capability of Sargassum muticum enriched fractions to protect cells on an oxidative stress condition. The concentration of the bioactive compounds was obtained by vacuum liquid chromatography applied on methanol (M) and 1:1 methanol:dichloromethane (MD) crude extracts, resulting in seven enriched fractions from the M extraction (MF2–MF8), and eight fractions from the MD extraction (MDF1–MDF8). All fractions were tested for cytotoxic properties on MCF-7 cells and the nontoxic ones were tested for their capacity to blunt the damaging effects of hydrogen peroxide-induced oxidative stress. The nontoxic effects were also confirmed in 3T3 fibroblast cells as a nontumor cell line. The antioxidant potential of each fraction, as well as changes in the cell’s real-time hydrogen peroxide production, in the mitochondrial membrane potential, and in Caspase-9 activity were evaluated. The results suggest that the protective effects evidenced by S. muticum can be related with the inhibition of hydrogen peroxide production and the inhibition of Caspase-9 activity. Full article

(This article belongs to the Special Issue Nutraceuticals and Functional Foods)

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Open AccessReview

Bioactive Secondary Metabolites from the Marine Sponge Genus Agelas

by Huawei Zhang, Menglian Dong, Jianwei Chen, Hong Wang, Karen Tenney and Phillip Crews

Mar. Drugs 2017, 15(11), 351; https://doi.org/10.3390/md15110351 - 8 Nov 2017

Cited by 37 | Viewed by 8305

Abstract

The marine sponge genus Agelas comprises a rich reservoir of species and natural products with diverse chemical structures and biological properties with potential application in new drug development. This review for the first time summarized secondary metabolites from Agelas sponges discovered in the [...] Read more.

The marine sponge genus Agelas comprises a rich reservoir of species and natural products with diverse chemical structures and biological properties with potential application in new drug development. This review for the first time summarized secondary metabolites from Agelas sponges discovered in the past 47 years together with their bioactive effects. Full article

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

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Open AccessFeature PaperArticle

Reclamation of Marine Chitinous Materials for the Production of α-Glucosidase Inhibitors via Microbial Conversion

by Van Bon Nguyen and San-Lang Wang

Mar. Drugs 2017, 15(11), 350; https://doi.org/10.3390/md15110350 - 7 Nov 2017

Cited by 35 | Viewed by 4613

Abstract

Six kinds of chitinous materials have been used as sole carbon/nitrogen (C/N) sources for producing α-glucosidase inhibitors (aGI) by Paenibacillus sp. TKU042. The aGI productivity was found to be highest in the culture supernatants using demineralized crab shell powder (deCSP) and demineralized shrimp [...] Read more.

Six kinds of chitinous materials have been used as sole carbon/nitrogen (C/N) sources for producing α-glucosidase inhibitors (aGI) by Paenibacillus sp. TKU042. The aGI productivity was found to be highest in the culture supernatants using demineralized crab shell powder (deCSP) and demineralized shrimp shell powder (deSSP) as the C/N source. The half maximal inhibitory concentration (IC₅₀) and maximum aGI activity of fermented deCSP (38 µg/mL, 98%), deSSP (108 µg/mL, 89%), squid pen powder (SPP) (422 µg/mL, 98%), and shrimp head powder (SHP) (455 µg/mL, 92%) were compared with those of fermented nutrient broth (FNB) (81 µg/mL, 93%) and acarbose (1095 µg/mL, 74%), a commercial antidiabetic drug. The result of the protein/chitin ratio on aGI production showed that the optimal ratio was 0.2/1. Fermented deCSP showed lower IC₅₀ and higher maximum inhibitory activity than those of acarbose against rat intestinal α-glucosidase. Full article

(This article belongs to the Special Issue Bioconversion of Marine Resources)

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Open AccessArticle

Evidence for a Saponin Biosynthesis Pathway in the Body Wall of the Commercially Significant Sea Cucumber Holothuria scabra

by Shahida Akter Mitu, Utpal Bose, Saowaros Suwansa-ard, Luke H. Turner, Min Zhao, Abigail Elizur, Steven M. Ogbourne, Paul Nicholas Shaw and Scott F. Cummins

Mar. Drugs 2017, 15(11), 349; https://doi.org/10.3390/md15110349 - 7 Nov 2017

Cited by 27 | Viewed by 6133

Abstract

The sea cucumber (phylum Echinodermata) body wall is the first line of defense and is well known for its production of secondary metabolites; including vitamins and triterpenoid glycoside saponins that have important ecological functions and potential benefits to human health. The genes involved [...] Read more.

The sea cucumber (phylum Echinodermata) body wall is the first line of defense and is well known for its production of secondary metabolites; including vitamins and triterpenoid glycoside saponins that have important ecological functions and potential benefits to human health. The genes involved in the various biosynthetic pathways are unknown. To gain insight into these pathways in an echinoderm, we performed a comparative transcriptome analysis and functional annotation of the body wall and the radial nerve of the sea cucumber Holothuria scabra; to define genes associated with body wall metabolic functioning and secondary metabolite biosynthesis. We show that genes related to signal transduction mechanisms were more highly represented in the H. scabra body wall, including genes encoding enzymes involved in energy production. Eight of the core triterpenoid biosynthesis enzymes were found, however, the identity of the saponin specific biosynthetic pathway enzymes remains unknown. We confirm the body wall release of at least three different triterpenoid saponins using solid phase extraction followed by ultra-high-pressure liquid chromatography-quadrupole time of flight-mass spectrometry. The resource we have established will help to guide future research to explore secondary metabolite biosynthesis in the sea cucumber. Full article

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Open AccessArticle

Cytotoxic and Antibacterial Compounds from the Coral-Derived Fungus Aspergillus tritici SP2-8-1

by Weiyi Wang, Yanyan Liao, Chao Tang, Xiaomei Huang, Zhuhua Luo, Jianming Chen and Peng Cai

Mar. Drugs 2017, 15(11), 348; https://doi.org/10.3390/md15110348 - 7 Nov 2017

Cited by 39 | Viewed by 5352

Abstract

Three novel compounds, 4-methyl-candidusin A (1), aspetritone A (2) and aspetritone B (3), were obtained from the culture of a coral-derived fungus Aspergillus tritici SP2-8-1, together with fifteen known compounds (4–18). Their structures, [...] Read more.

Three novel compounds, 4-methyl-candidusin A (1), aspetritone A (2) and aspetritone B (3), were obtained from the culture of a coral-derived fungus Aspergillus tritici SP2-8-1, together with fifteen known compounds (4–18). Their structures, including absolute configurations, were assigned based on NMR, MS, and time-dependent density functional theory (TD-DFT) ECD calculations. Compounds 2 and 5 exhibited better activities against methicillin-resistant strains of S. aureus (MRSA) ATCC 43300 and MRSA CGMCC 1.12409 than the positive control chloramphenicol. Compound 5 displayed stronger anti-MRSA and lower cytotoxic activities than 2, and showed stronger antibacterial activities against strains of Vibrio vulnificus, Vibrio rotiferianus, and Vibrio campbellii than the other compounds. Compounds 2 and 10 exhibited significantly stronger cytotoxic activities against human cancer cell lines HeLa, A549, and Hep G2 than the other compounds. Preliminary structure–activity relationship studies indicated that prenylation of terphenyllin or candidusin and the tetrahydrobenzene moiety in anthraquinone derivatives may influence their bioactivity. Full article

(This article belongs to the Special Issue Bioactive Compounds from Marine-Derived Aspergillus, Penicillium, Talaromyces and Trichoderma Species)

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Open AccessArticle

Immunoenhancement Effects of Glycosaminoglycan from Apostichopus japonicus: In Vitro and In Cyclophosphamide-Induced Immunosuppressed Mice Studies

by Han Wang, Shuang Yang, Yuanhong Wang, Tingfu Jiang, Shuai Li and Zhihua Lv

Mar. Drugs 2017, 15(11), 347; https://doi.org/10.3390/md15110347 - 7 Nov 2017

Cited by 30 | Viewed by 4893

Abstract

In this study, the immunomodulatory activities of Apostichopus japonicus glycosaminoglycan (AHG) on the nature killer (NK) cells, cytotoxic T lymphocytes (CTLs) and cyclophosphamide (CY)-treated mice were investigated. After stimulation with multiple concentrations of AHG (0–100 μg/mL), NK cells and CTLs displayed outperformance against [...] Read more.

In this study, the immunomodulatory activities of Apostichopus japonicus glycosaminoglycan (AHG) on the nature killer (NK) cells, cytotoxic T lymphocytes (CTLs) and cyclophosphamide (CY)-treated mice were investigated. After stimulation with multiple concentrations of AHG (0–100 μg/mL), NK cells and CTLs displayed outperformance against YAC-1 and B16 cells, respectively. Furthermore, the mitogen-induced splenic lymphocyte proliferation in CY-induced immunosuppressed mice was significantly promoted by AHG. In addition, the administration of AHG dramatically increased the splenocytes Ca²⁺ concentration and the delayed-type hypersensitivity (DTH) reaction in a dose-dependent manner. Besides, AHG could strongly increase the total antioxidant capacity (T-AOC), the activities of superoxidase dismutase (SOD), catalase (CAT) as well as glutathione peroxidase (GSH-PX), and could decrease the malondialdehyde (MDA) level in the heart, kidney and liver. These findings indicated that AHG played an important role in the immune enhancement and protection against CY-induced immunosuppression and oxidative damage. Our findings provide experimental evidence for further research and possible immunostimulatory applications of AHG in clinical practice. Full article

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Open AccessReview

Application of Chitosan, Chitooligosaccharide, and Their Derivatives in the Treatment of Alzheimer’s Disease

by Qian-Qian Ouyang, Shannon Zhao, Si-Dong Li and Cai Song

Mar. Drugs 2017, 15(11), 322; https://doi.org/10.3390/md15110322 - 7 Nov 2017

Cited by 59 | Viewed by 7489

Abstract

Classic hypotheses of Alzheimer’s disease (AD) include cholinergic neuron death, acetylcholine (ACh) deficiency, metal ion dynamic equilibrium disorder, and deposition of amyloid and tau. Increased evidence suggests neuroinflammation and oxidative stress may cause AD. However, none of these factors induces AD independently, but [...] Read more.

Classic hypotheses of Alzheimer’s disease (AD) include cholinergic neuron death, acetylcholine (ACh) deficiency, metal ion dynamic equilibrium disorder, and deposition of amyloid and tau. Increased evidence suggests neuroinflammation and oxidative stress may cause AD. However, none of these factors induces AD independently, but they are all associated with the formation of Aβ and tau proteins. Current clinical treatments based on ACh deficiency can only temporarily relieve symptoms, accompanied with many side-effects. Hence, searching for natural neuroprotective agents, which can significantly improve the major symptoms and reverse disease progress, have received great attention. Currently, several bioactive marine products have shown neuroprotective activities, immunomodulatory and anti-inflammatory effects with low toxicity and mild side effects in laboratory studies. Recently, chitosan (CTS), chitooligosaccharide (COS) and their derivatives from exoskeletons of crustaceans and cell walls of fungi have shown neuroprotective and antioxidative effects, matrix metalloproteinase inhibition, anti-HIV and anti-inflammatory properties. With regards to the hypotheses of AD, the neuroprotective effect of CTS, COS, and their derivatives on AD-like changes in several models have been reported. CTS and COS exert beneficial effects on cognitive impairments via inhibiting oxidative stress and neuroinflammation. They are also a new type of non-toxic β-secretase and AChE inhibitor. As neuroprotective agents, they could reduce the cell membrane damage caused by copper ions and decrease the content of reactive oxygen species. This review will focus on their anti-neuroinflammation, antioxidants and their inhibition of β-amyloid, acetylcholinesterase and copper ions adsorption. Finally, the limitations and future work will be discussed. Full article

(This article belongs to the Special Issue Marine Compounds in Neurodegenerative Diseases)

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Open AccessArticle

AS1041, a Novel Synthesized Derivative of Marine Natural Compound Aspergiolide A, Arrests Cell Cycle, Induces Apoptosis, and Inhibits ERK Activation in K562 Cells

by Fengli Yuan, Liang Qiao, Yinghan Chen, Xin Qi, Yankai Liu, Dehai Li, Qianqun Gu, Jing Li and Ming Liu

Mar. Drugs 2017, 15(11), 346; https://doi.org/10.3390/md15110346 - 4 Nov 2017

Cited by 10 | Viewed by 4813

Abstract

AS1041 is a novel synthesized anthraquinone lactone derivative of marine natural compound aspergiolide A (ASP-A) with new structure skeleton and marked cytotoxicity in cancer cells. To study its cytotoxicity in detail, we evaluated its activity on human K562 chronic myelogenous leukemia cells and [...] Read more.

AS1041 is a novel synthesized anthraquinone lactone derivative of marine natural compound aspergiolide A (ASP-A) with new structure skeleton and marked cytotoxicity in cancer cells. To study its cytotoxicity in detail, we evaluated its activity on human K562 chronic myelogenous leukemia cells and investigated the related molecule mechanisms. AS1041 significantly inhibited the proliferation and colony formation of K562 cells. Moreover, AS1041 arrested cell cycle progression at G2/M phase in a concentration-dependent manner, and also caused concentration- and time-dependent induction of apoptosis. In addition, the molecular mechanisms investigation showed that AS1041 did not localize in the cellular nucleus and did not affect topoisomerases I or II. However, AS1041 could inactivate extracellular signal-regulated kinase (ERK) and contribute to AS1041-induced apoptosis. We concluded that AS1041 was cytotoxic to K562 leukemia cells and the cytotoxicity related to the cell cycle arrest, apoptosis induction, and ERK inhibition. These results implied that AS1041 was a novel derivative of ASP-A with significant cytotoxicity to chronic myelogenous leukemia cells and may have therapeutic potential for the treatment of cancer and leukemia. Full article

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Open AccessArticle

Degradation of Polysaccharides from Grateloupia filicina and Their Antiviral Activity to Avian Leucosis Virus Subgroup J

by Yuhao Sun, Xiaolin Chen, Ziqiang Cheng, Song Liu, Huahua Yu, Xueqin Wang and Pengcheng Li

Mar. Drugs 2017, 15(11), 345; https://doi.org/10.3390/md15110345 - 3 Nov 2017

Cited by 23 | Viewed by 4639

Abstract

In this study, polysaccharides from Grateloupia filicinia (GFP) were extracted and several low molecular weight (Mw) G. filicina polysaccharides (LGFPs) were prepared by the hydrogen peroxide (H₂O₂) oxidation method. Additionally, the effect of different experimental conditions on the degradation [...] Read more.

In this study, polysaccharides from Grateloupia filicinia (GFP) were extracted and several low molecular weight (Mw) G. filicina polysaccharides (LGFPs) were prepared by the hydrogen peroxide (H₂O₂) oxidation method. Additionally, the effect of different experimental conditions on the degradation of GFP was determined. Results showed that the GFP degradation rate was positively related to H₂O₂ concentration and temperature, and negatively related to pH. Chemical analysis and Fourier transform infrared spectra (FT-IR) of GFP and LGFPs showed that the degradation caused a slight decrease of total sugar and sulfate content. However, there was no obvious change for monosaccharide contents. Then, the anti-ALV-J activity of GFP and LGFPs were determined in vitro. Results revealed that all of the samples could significantly inhibit ALV-J and lower Mw LGFPs exhibited a stronger suppression, and that the fraction LGFP-3 with Mw 8.7 kDa had the best effect. In addition, the reaction phase assays showed that the inhibition effect was mainly because of the blocking virus adsorption to host cells. Moreover, real-time PCR, western-blot, and IFA were further applied to evaluate the blocking effects of LGFP-3. Results showed that the gene relative expression and gp85 protein for LGFPS-3 groups were all reduced. Data from IFA showed that there was less virus infected cells for 1000 and 200 μg/mL LGFPS-3 groups when compared to virus control. Therefore, lower Mw polysaccharides from G. filicina might supply a good choice for ALV-J prevention and treatment. Full article

(This article belongs to the Collection Marine Polysaccharides)

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Open AccessArticle

5-Alkylresorcinol Derivatives from the Bryozoan Schizomavella mamillata: Isolation, Synthesis, and Antioxidant Activity

by María J. Ortega, Juan J. Pantoja, Carolina De los Reyes and Eva Zubía

Mar. Drugs 2017, 15(11), 344; https://doi.org/10.3390/md15110344 - 2 Nov 2017

Cited by 14 | Viewed by 4957

Abstract

The chemical study of the bryozoan Schizomavella mamillata has led to the isolation of six new 5-alkylresorcinol derivatives, schizols A–F (1–6), whose structures were established by spectrocospic means. Schizol A (1) exhibits a (E)-6-phenylnon-5-enyl moiety [...] Read more.

The chemical study of the bryozoan Schizomavella mamillata has led to the isolation of six new 5-alkylresorcinol derivatives, schizols A–F (1–6), whose structures were established by spectrocospic means. Schizol A (1) exhibits a (E)-6-phenylnon-5-enyl moiety linked to the C-5 of a resorcinol ring, while in schizol B (2) the substituent at C-5 contains an unusual 1,2-dihydrocyclobutabenzene moiety. Schizols C (3) and D (4) have been characterized as the 1-sulfate derivatives of 1 and 2, respectively, and schizols E (5) and F (6) are the corresponding 1,3-disulfates. Schizol A (1) has been synthetized from 3,5-dimethoxybenzaldehyde through a sequence involving a Wittig reaction for the construction of the C-1′,C-2′ bond and a Julia–Kocienski olefination for the synthesis of the C-5′,C-6′ double bond. In the ABTS (2,2′-azinobis(3-ethylbenzothiazoline-6-sulphonic acid)) antioxidant assay, the natural compounds schizol A (1) and schizol B (2) showed higher radical scavenging activity than the Trolox standard. Full article

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Open AccessArticle

Insight into the Mechanism of Action of Marine Cytotoxic Thiazinoquinones

by Concetta Imperatore, Paola Cimino, Gerardo Cebrián-Torrejón, Marco Persico, Anna Aiello, Maria Senese, Caterina Fattorusso, Marialuisa Menna and Antonio Doménech-Carbó

Mar. Drugs 2017, 15(11), 335; https://doi.org/10.3390/md15110335 - 2 Nov 2017

Cited by 11 | Viewed by 4314

Abstract

The electrochemical response of four natural cytotoxic thiazinoquinones isolated from the Aplidium species was studied using conventional solution-phase and solid-state techniques, based on the voltammetry of immobilized particles methodology. The interaction with O₂ and electrochemically generated reactive oxygen species (ROS) was electrochemically [...] Read more.

The electrochemical response of four natural cytotoxic thiazinoquinones isolated from the Aplidium species was studied using conventional solution-phase and solid-state techniques, based on the voltammetry of immobilized particles methodology. The interaction with O₂ and electrochemically generated reactive oxygen species (ROS) was electrochemically monitored. At the same time, a molecular modeling study including density functional theory (DFT) calculations was performed in order to analyze the conformational and electronic properties of the natural thiazinoquinones, as well as those of their reduced intermediates. The obtained electrochemical and computational results were analyzed and correlated to cytotoxic activity of these compounds, highlighting some features possibly related to their mechanism of action. Full article

(This article belongs to the Special Issue From Bioactive Compounds to New Drugs: Commemorative Issue Dedicated to Professor Ernesto Fattorusso (1937-2012))

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Discovery of Novel Bromophenol Hybrids as Potential Anticancer Agents through the Ros-Mediated Apoptotic Pathway: Design, Synthesis and Biological Evaluation

by Li-Jun Wang, Chuan-Long Guo, Xiang-Qian Li, Shuai-Yu Wang, Bo Jiang, Yue Zhao, Jiao Luo, Kuo Xu, Hua Liu, Shu-Ju Guo, Ning Wu and Da-Yong Shi

Mar. Drugs 2017, 15(11), 343; https://doi.org/10.3390/md15110343 - 1 Nov 2017

Cited by 24 | Viewed by 4624

Abstract

A series of bromophenol hybrids with N-containing heterocyclic moieties were designed, and their anticancer activities against a panel of five human cancer cell lines (A549, Bel7402, HepG2, HCT116 and Caco2) using MTT assay in vitro were explored. Among them, thirteen compounds (17a [...] Read more.

A series of bromophenol hybrids with N-containing heterocyclic moieties were designed, and their anticancer activities against a panel of five human cancer cell lines (A549, Bel7402, HepG2, HCT116 and Caco2) using MTT assay in vitro were explored. Among them, thirteen compounds (17a, 17b, 18a, 19a, 19b, 20a, 20b, 21a, 21b, 22a, 22b, 23a, and 23b) exhibited significant inhibitory activity against the tested cancer cell lines. The structure-activity relationships (SARs) of bromophenol derivatives were discussed. The promising candidate compound 17a could induce cell cycle arrest at G0/G1 phase and induce apoptosis in A549 cells, as well as caused DNA fragmentations, morphological changes and ROS generation by the mechanism studies. Furthermore, compound 17a suppression of Bcl-2 levels (decrease in the expression of the anti-apoptotic proteins Bcl-2 and down-regulation in the expression levels of Bcl-2) in A549 cells were observed, along with activation caspase-3 and PARP, which indicated that compound 17a induced A549 cells apoptosis in vitro through the ROS-mediated apoptotic pathway. These results might be useful for bromophenol derivatives to be explored and developed as novel anticancer drugs. Full article

(This article belongs to the Special Issue Synthesis of Marine-Derived Compounds)

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Antimicrobial and Anti-Proliferative Effects of Skin Mucus Derived from Dasyatis pastinaca (Linnaeus, 1758)

by Virginia Fuochi, Giovanni Li Volti, Giuseppina Camiolo, Francesco Tiralongo, Cesarina Giallongo, Alfio Distefano, Giulio Petronio Petronio, Ignazio Barbagallo, Maria Viola, Pio Maria Furneri, Michelino Di Rosa, Roberto Avola and Daniele Tibullo

Mar. Drugs 2017, 15(11), 342; https://doi.org/10.3390/md15110342 - 1 Nov 2017

Cited by 54 | Viewed by 7282

Abstract

Resistance to chemotherapy occurs in various diseases (i.e., cancer and infection), and for this reason, both are very difficult to treat. Therefore, novel antimicrobial and chemotherapic drugs are needed for effective antibiotic therapy. The aim of the present study was to assess the [...] Read more.

Resistance to chemotherapy occurs in various diseases (i.e., cancer and infection), and for this reason, both are very difficult to treat. Therefore, novel antimicrobial and chemotherapic drugs are needed for effective antibiotic therapy. The aim of the present study was to assess the antimicrobial and anti-proliferative effects of skin mucus derived from Dasyatis pastinaca (Linnaeus, 1758). Our results showed that skin mucus exhibited a significant and specific antibacterial activity against Gram-negative bacteria but not against Gram-positive bacteria. Furthermore, we also observed a significant antifungal activity against some strains of Candida spp. Concerning anti-proliferative activity, we showed that fish mucus was specifically toxic for acute leukemia cells (HL60) with an inhibition of proliferation in a dose dependent manner (about 52% at 1000 μg/mL of fish skin mucous, FSM). Moreover, we did not observe effects in healthy cells, in neuroblastoma cells (SH-SY5Y), and multiple myeloma cell lines (MM1, U266). Finally, it exhibited strong expression and activity of chitinase which may be responsible, at least in part, for the aforementioned results. Full article

(This article belongs to the Special Issue Progress on Marine Natural Products as Lead Compounds)

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Cucumarioside A₂-2 Causes Macrophage Activation in Mouse Spleen

by Evgeny A. Pislyagin, Igor V. Manzhulo, Tatiana Y. Gorpenchenko, Pavel S. Dmitrenok, Sergey A. Avilov, Alexandra S. Silchenko, Yun-Ming Wang and Dmitry L. Aminin

Mar. Drugs 2017, 15(11), 341; https://doi.org/10.3390/md15110341 - 1 Nov 2017

Cited by 18 | Viewed by 6770

Abstract

The immunomodulatory effect of triterpene glycoside cucumarioside A₂-2 (CA₂-2), isolated from the Far Eastern sea cucumber Cucumaria japonica, was compared with lipopolysaccharide (LPS) on mouse spleen. It has been shown that the intraperitoneal (i.p.) glycoside administration [...] Read more.

The immunomodulatory effect of triterpene glycoside cucumarioside A₂-2 (CA₂-2), isolated from the Far Eastern sea cucumber Cucumaria japonica, was compared with lipopolysaccharide (LPS) on mouse spleen. It has been shown that the intraperitoneal (i.p.) glycoside administration leads to increased spleen macrophage activating markers iba-1, IL-1β, iNOs, ROS and NO formation, with additional change of macrophage phenotype to M1. The mass spectrometry profiles of peptide/protein were obtained using MALDI-TOF-MS on the different parts of spleen sections isolated by laser mircodissection techniques. It was found that i.p. stimulation of animals with CA₂-2 leads to marked changes in the intensity of the characteristic peaks of spleen peptides/proteins, primarily in red pulp. Full article

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Open AccessFeature PaperArticle

Lipophilic Fraction of Cultivated Bifurcaria bifurcata R. Ross: Detailed Composition and In Vitro Prospection of Current Challenging Bioactive Properties

by Sónia A. O. Santos, Stephanie S. Trindade, Catia S. D. Oliveira, Paula Parreira, Daniela Rosa, Maria F. Duarte, Isabel Ferreira, Maria T. Cruz, Andreia M. Rego, Maria H. Abreu, Silvia M. Rocha and Armando J. D. Silvestre

Mar. Drugs 2017, 15(11), 340; https://doi.org/10.3390/md15110340 - 1 Nov 2017

Cited by 26 | Viewed by 6064

Abstract

Macroalgae have been seen as an alternative source of molecules with promising bioactivities to use in the prevention and treatment of current lifestyle diseases. In this vein, the lipophilic fraction of short-term (three weeks) cultivated Bifurcaria bifurcata was characterized in detail by gas [...] Read more.

Macroalgae have been seen as an alternative source of molecules with promising bioactivities to use in the prevention and treatment of current lifestyle diseases. In this vein, the lipophilic fraction of short-term (three weeks) cultivated Bifurcaria bifurcata was characterized in detail by gas chromatography–mass spectrometry (GC-MS). B. bifurcata dichloromethane extract was composed mainly by diterpenes (1892.78 ± 133.97 mg kg⁻¹ dry weight (DW)), followed by fatty acids, both saturated (550.35 ± 15.67 mg kg⁻¹ DW) and unsaturated (397.06 ± 18.44 mg kg⁻¹ DW). Considerable amounts of sterols, namely fucosterol (317.68 ± 26.11 mg kg⁻¹ DW) were also found. In vitro tests demonstrated that the B. bifurcata lipophilic extract show antioxidant, anti-inflammatory and antibacterial activities (against both Gram-positive and Gram-negative bacteria), using low extract concentrations (in the order of µg mL⁻¹). Enhancement of antibiotic activity of drug families of major clinical importance was observed by the use of B. bifurcata extract. This enhancement of antibiotic activity depends on the microbial strain and on the antibiotic. This work represents the first detailed phytochemical study of the lipophilic extract of B. bifurcata and is, therefore, an important contribution for the valorization of B. bifurcata macroalgae, with promising applications in functional foods, nutraceutical, cosmetic and biomedical fields. Full article

(This article belongs to the Special Issue Marine Lipids 2017)

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Diverse Secondary Metabolites from the Marine-Derived Fungus Dichotomomyces cejpii F31-1

by Yan-Xiu Chen, Meng-Yang Xu, Hou-Jin Li, Kun-Jiao Zeng, Wen-Zhe Ma, Guo-Bao Tian, Jun Xu, De-Po Yang and Wen-Jian Lan

Mar. Drugs 2017, 15(11), 339; https://doi.org/10.3390/md15110339 - 1 Nov 2017

Cited by 31 | Viewed by 4717

Abstract

By adding l-tryptophan and l-phenylalanine to GPY medium, twenty-eight compounds, including amides, polyketides, a sesquiterpenoid, a diterpenoid, a meroterpenoid, diketopiperazines, β-carbolines, fumiquinazolines, and indole alkaloids, were discovered from the marine-derived fungus Dichotomomyces cejpii F31-1, demonstrating the tremendous biosynthetic potential of this [...] Read more.

By adding l-tryptophan and l-phenylalanine to GPY medium, twenty-eight compounds, including amides, polyketides, a sesquiterpenoid, a diterpenoid, a meroterpenoid, diketopiperazines, β-carbolines, fumiquinazolines, and indole alkaloids, were discovered from the marine-derived fungus Dichotomomyces cejpii F31-1, demonstrating the tremendous biosynthetic potential of this fungal strain. Among these compounds, four amides dichotomocejs A–D (1–4), one polyketide dichocetide A (5), and two diketopiperazines dichocerazines A–B (15 and 16) are new. The structures of these new compounds were determined by interpreting detailed spectroscopic data as well as calculating optical rotation values and ECD spectra. Obviously, Dichotomomyces cejpii can effectively use an amino acid-directed strategy to enhance the production of nitrogen-containing compounds. Dichotomocej A (1) displayed moderate cytotoxicity against the human rhabdomyosarcoma cell line RD with an IC₅₀ value of 39.1 µM, and pityriacitrin (22) showed moderate cytotoxicity against the human colon carcinoma cell line HCT116 with an IC₅₀ value of 35.1 µM. Full article

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Isolation and Characterization of Polysaccharides from Oysters (Crassostrea gigas) with Anti-Tumor Activities Using an Aqueous Two-Phase System

by Kit-Leong Cheong, Li-Xuan Xia and Yang Liu

Mar. Drugs 2017, 15(11), 338; https://doi.org/10.3390/md15110338 - 1 Nov 2017

Cited by 43 | Viewed by 5917

Abstract

In this study, a simple aqueous two-phase system (ATPS) was employed for concurrent purification of oyster polysaccharides. The chemical structure and anti-tumor activities of purified oyster polysaccharides (OP-1) were also investigated. Under optimal ATPS conditions, oyster polysaccharides can be partitioned in the bottom [...] Read more.

In this study, a simple aqueous two-phase system (ATPS) was employed for concurrent purification of oyster polysaccharides. The chemical structure and anti-tumor activities of purified oyster polysaccharides (OP-1) were also investigated. Under optimal ATPS conditions, oyster polysaccharides can be partitioned in the bottom phase with 67.02% extraction efficiency. The molecular weight of OP-1 was determined as 3480 Da. OP-1 is a (1→4)-α-d-glucosyl backbone and branching points located at O-3 of glucose with a terminal-d-Glcp. The anti-tumor activity assay showed that OP-1 exhibited good activities, including promotion of splenocyte proliferation, IL-2 release, and inhibition of HepG2 cell proliferation. Additionally, OP-1 had no in vivo toxicity. This finding suggests that ATPS is a much simpler and greener system, and it opens up new possibilities in the large-scale separation of active polysaccharides from oysters. OP-1 could be used by the health food and pharmaceutical therapies as potential anti-cancer adjuvants. Full article

(This article belongs to the Special Issue Marine Oligosaccharides and Polysaccharides)

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Open AccessArticle

Carrageenans-Sulfated Polysaccharides from Red Seaweeds as Matrices for the Inclusion of Echinochrome

by Irina M. Yermak, Natalia P. Mischchenko, Viktoria N. Davydova, Valery P. Glazunov, Daria V. Tarbeeva, Anna O. Kravchenko, Evgeniya A. Pimenova and Irina V. Sorokina

Mar. Drugs 2017, 15(11), 337; https://doi.org/10.3390/md15110337 - 1 Nov 2017

Cited by 35 | Viewed by 4181

Abstract

The possibility of using different types of carrageenans (CRG) as matrixes for incorporating of echinochrome A (Ech) was investigated. Ech interacts with carrageenans and is incorporated into the macromolecular structure of the polysaccharide. The inclusion of Ech in carrageenan matrices decreased its oxidative [...] Read more.

The possibility of using different types of carrageenans (CRG) as matrixes for incorporating of echinochrome A (Ech) was investigated. Ech interacts with carrageenans and is incorporated into the macromolecular structure of the polysaccharide. The inclusion of Ech in carrageenan matrices decreased its oxidative degradation and improved its solubility. The changing in the charge and morphology of CRGs during binding with Ech was observed. The rate of Ech release from CRG matrices depended on the structure of the used polysaccharide and the presence of specific ions. The gastroprotective effect of CRG/Ech complexes was investigated on the model of stomach ulcers induced by indomethacin in rats. Complexes of CRG/Ech exhibited significant gastroprotective activity that exceeded the activity of the reference drug Phosphalugel. The gastroprotective effect of the complexes can be associated with their protective layer on the surface of the mucous membrane of a stomach. Full article

(This article belongs to the Special Issue Marine Biomaterials II, 2017)

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Pseudane-VII Isolated from Pseudoalteromonas sp. M2 Ameliorates LPS-Induced Inflammatory Response In Vitro and In Vivo

by Mi Eun Kim, Inae Jung, Jong Suk Lee, Ju Yong Na, Woo Jung Kim, Young-Ok Kim, Yong-Duk Park and Jun Sik Lee

Mar. Drugs 2017, 15(11), 336; https://doi.org/10.3390/md15110336 - 1 Nov 2017

Cited by 24 | Viewed by 4837

Abstract

The ocean is a rich resource of flora, fauna, food, and biological products. We found a wild-type bacterial strain, Pseudoalteromonas sp. M2, from marine water and isolated various secondary metabolites. Pseudane-VII is a compound isolated from the Pseudoalteromonas sp. M2 metabolite that possesses [...] Read more.

The ocean is a rich resource of flora, fauna, food, and biological products. We found a wild-type bacterial strain, Pseudoalteromonas sp. M2, from marine water and isolated various secondary metabolites. Pseudane-VII is a compound isolated from the Pseudoalteromonas sp. M2 metabolite that possesses anti-melanogenic activity. Inflammation is a response of the innate immune system to microbial infections. Macrophages have a critical role in fighting microbial infections and inflammation. Recent studies reported that various compounds derived from natural products can regulate immune responses including inflammation. However, the anti-inflammatory effects and mechanism of pseudane-VII in macrophages are still unknown. In this study, we investigated the anti-inflammatory effects of pseudane-VII. In present study, lipopolysaccharide (LPS)-induced nitric oxide (NO) production was significantly decreased by pseudane-VII treatment at 6 μM. Moreover, pseudane-VII treatment dose-dependently reduced mRNA levels of pro-inflammatory cytokines including inos, cox-2, il-1β, tnf-α, and il-6 in LPS-stimulated macrophages. Pseudane-VII also diminished iNOS protein levels and IL-1β secretion. In addition, Pseudane-VII elicited anti-inflammatory effects by inhibiting ERK, JNK, p38, and nuclear factor (NF)-κB-p65 phosphorylation. Consistently, pseudane-VII was also shown to inhibit the LPS-stimulated release of IL-1β and expression of iNOS in mice. These results suggest that pseudane-VII exerted anti-inflammatory effects on LPS-stimulated macrophage activation via inhibition of ERK, JNK, p38 MAPK phosphorylation, and pro-inflammatory gene expression. These findings may provide new approaches in the effort to develop anti-inflammatory therapeutics. Full article

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Mar. Drugs, Volume 15, Issue 11 (November 2017) – 34 articles

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