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Mar. Drugs, Volume 14, Issue 8 (August 2016) – 18 articles

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973 KiB  
Article
An Unusual Conformational Isomer of Verrucosidin Backbone from a Hydrothermal Vent Fungus, Penicillium sp. Y-50-10
by Chengqian Pan, Yutong Shi, Bibi Nazia Auckloo, Xuegang Chen, Chen-Tung Arthur Chen, Xinyi Tao and Bin Wu
Mar. Drugs 2016, 14(8), 156; https://doi.org/10.3390/md14080156 - 18 Aug 2016
Cited by 19 | Viewed by 5602
Abstract
A new verrucosidin derivative, methyl isoverrucosidinol (1), was isolated from the marine fungus Penicillium sp. Y-50-10, dwelling in sulfur rich sediment in the Kueishantao hydrothermal vents off Taiwan. The structure was established by spectroscopic means including HRMS and 2D-NMR spectroscopic analysis. [...] Read more.
A new verrucosidin derivative, methyl isoverrucosidinol (1), was isolated from the marine fungus Penicillium sp. Y-50-10, dwelling in sulfur rich sediment in the Kueishantao hydrothermal vents off Taiwan. The structure was established by spectroscopic means including HRMS and 2D-NMR spectroscopic analysis. The absolute configuration was defined mainly by comparison of quantum chemical TDDFT calculated and experimental ECD spectra. Among hitherto known compounds with a verrucosidine backbone isolated from natural resource, compound 1 represents the first example of a new conformational isomer of its skeleton, exhibiting antibiotic activity against Bacillus subtilis with MIC value 32 μg/mL. Full article
(This article belongs to the Special Issue Marine Fungal Natural Products)
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768 KiB  
Article
Mirabolides A and B; New Cytotoxic Glycerides from the Red Sea Sponge Theonella mirabilis
by Dina R. Abou-Hussein and Diaa T. A. Youssef
Mar. Drugs 2016, 14(8), 155; https://doi.org/10.3390/md14080155 - 18 Aug 2016
Cited by 4 | Viewed by 5904
Abstract
As a part of our continuing work to find out bioactive lead molecules from marine invertebrates, the CHCl3 fraction of the organic extract of the Red Sea sponge Theonella mirabilis showed cytotoxic activity in our primary screen. Bioassay-guided purification of the active [...] Read more.
As a part of our continuing work to find out bioactive lead molecules from marine invertebrates, the CHCl3 fraction of the organic extract of the Red Sea sponge Theonella mirabilis showed cytotoxic activity in our primary screen. Bioassay-guided purification of the active fractions of the sponge’s extract resulted in the isolation of two new glycerides, mirabolides A and B (1 and 2), together with the reported 4-methylene sterols, conicasterol (3) and swinhosterol B (4). The structures of the compounds were assigned by interpretation of their 1D (1H, 13C), 2D (COSY, HSQC, HMBC, ROESY) NMR spectral data and high-resolution mass determinations. Compounds 14 displayed marked cytotoxic activity against human breast adenocarcinoma cell line (MCF-7) with IC50 values of 16.4, 5.18, 6.23 and 3.0 μg/mL, respectively, compared to 5.4 μg/mL observed by doxorubicin as reference drug. Full article
(This article belongs to the Collection Bioactive Compounds from Marine Invertebrates)
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1912 KiB  
Article
Tumor Protein (TP)-p53 Members as Regulators of Autophagy in Tumor Cells upon Marine Drug Exposure
by Edward A. Ratovitski
Mar. Drugs 2016, 14(8), 154; https://doi.org/10.3390/md14080154 - 16 Aug 2016
Cited by 28 | Viewed by 6722
Abstract
Targeting autophagic pathways might play a critical role in designing novel chemotherapeutic approaches in the treatment of human cancers, and the prevention of tumor-derived chemoresistance. Marine compounds were found to decrease tumor cell growth in vitro and in vivo. Some of them were [...] Read more.
Targeting autophagic pathways might play a critical role in designing novel chemotherapeutic approaches in the treatment of human cancers, and the prevention of tumor-derived chemoresistance. Marine compounds were found to decrease tumor cell growth in vitro and in vivo. Some of them were shown to induce autophagic flux in tumor cells. In this study, we observed that the selected marine life-derived compounds (Chromomycin A2, Psammaplin A, and Ilimaquinone) induce expression of several autophagic signaling intermediates in human squamous cell carcinoma, glioblastoma, and colorectal carcinoma cells in vitro through a transcriptional regulation by tumor protein (TP)-p53 family members. These conclusions were supported by specific qPCR expression analysis, luciferase reporter promoter assay, and chromatin immunoprecipitation of promoter sequences bound to the TP53 family proteins, and silencing of the TP53 members in tumor cells. Full article
(This article belongs to the Special Issue Marine Compounds as Modulators of Autophagy and Lysosomal Activity)
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2467 KiB  
Article
Anticancer Activity of a Hexapeptide from Skate (Raja porosa) Cartilage Protein Hydrolysate in HeLa Cells
by Xin Pan, Yu-Qin Zhao, Fa-Yuan Hu, Chang-Feng Chi and Bin Wang
Mar. Drugs 2016, 14(8), 153; https://doi.org/10.3390/md14080153 - 16 Aug 2016
Cited by 66 | Viewed by 6999
Abstract
In this study, the hexapeptide Phe-Ile-Met-Gly-Pro-Tyr (FIMGPY), which has a molecular weight of 726.9 Da, was separated from skate (Raja porosa) cartilage protein hydrolysate using ultrafiltration and chromatographic methods, and its anticancer activity was evaluated in HeLa cells. Methylthiazolyldiphenyl-tetrazolium bromide (MTT) [...] Read more.
In this study, the hexapeptide Phe-Ile-Met-Gly-Pro-Tyr (FIMGPY), which has a molecular weight of 726.9 Da, was separated from skate (Raja porosa) cartilage protein hydrolysate using ultrafiltration and chromatographic methods, and its anticancer activity was evaluated in HeLa cells. Methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay indicated that FIMGPY exhibited high, dose-dependent anti-proliferation activities in HeLa cells with an IC50 of 4.81 mg/mL. Acridine orange/ethidium bromide (AO/EB) fluorescence staining and flow cytometry methods confirmed that FIMGPY could inhibit HeLa cell proliferation by inducing apoptosis. Western blot assay revealed that the Bax/Bcl-2 ratio and relative intensity of caspase-3 in HeLa cells treated with 7-mg/mL FIMGPY were 2.63 and 1.83, respectively, significantly higher than those of the blank control (p < 0.01). Thus, FIMGPY could induce apoptosis by upregulating the Bax/Bcl-2 ratio and caspase-3 activation. Using a DNA ladder method further confirmed that the anti-proliferation activity of FIMGPY was attributable to its role in inducing apoptosis. These results suggest that FIMGPY from skate cartilage protein hydrolysate may have applications as functional foods and nutraceuticals for the treatment and prevention of cancer. Full article
(This article belongs to the Special Issue Marine Proteins and Peptides)
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10169 KiB  
Article
Recombinant Expression of a Modified Shrimp Anti-Lipopolysaccharide Factor Gene in Pichia pastoris GS115 and Its Characteristic Analysis
by Hui Yang, Shihao Li, Fuhua Li, Kuijie Yu, Fusheng Yang and Jianhai Xiang
Mar. Drugs 2016, 14(8), 152; https://doi.org/10.3390/md14080152 - 09 Aug 2016
Cited by 26 | Viewed by 7381
Abstract
Anti-lipopolysaccharide factors (ALFs) with a LPS-binding domain (LBD) are considered to have broad spectrum antimicrobial activities and certain antiviral properties in crustaceans. FcALF2 was one isoform of ALFs isolated from the Chinese shrimp Fenneropenaeus chinensis. Our previous study showed that a modified [...] Read more.
Anti-lipopolysaccharide factors (ALFs) with a LPS-binding domain (LBD) are considered to have broad spectrum antimicrobial activities and certain antiviral properties in crustaceans. FcALF2 was one isoform of ALFs isolated from the Chinese shrimp Fenneropenaeus chinensis. Our previous study showed that a modified LBD domain (named LBDv) of FcALF2 exhibited a highly enhanced antimicrobial activity. In the present study, a modified FcALF2 gene (mFcALF2), in which the LBD was substituted by LBDv, was designed and synthesized. This gene was successfully expressed in yeast Pichia pastoris GS115 eukaryotic expression system, and the characteristics of the recombinant protein mFcALF2 were analyzed. mFcALF2 exhibited apparent antibacterial activities against Gram-negative bacteria, including Escherichia coli, Vibrio alginolyticus, Vibrio harveyi, and Vibrio parahaemolyticus, and Gram-positive bacteria, including Bacillus licheniformis and Staphylococcus epidermidis. In addition, mFcALF2 could reduce the propagation of white spot syndrome virus (WSSV) in vivo by pre-incubation with virus. The present study paves the way for developing antimicrobial drugs in aquaculture. Full article
(This article belongs to the Special Issue Marine Proteins and Peptides)
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2125 KiB  
Article
Anti-Dengue Virus Constituents from Formosan Zoanthid Palythoa mutuki
by Jin-Ching Lee, Fang-Rong Chang, Shu-Rong Chen, Yu-Hsuan Wu, Hao-Chun Hu, Yang-Chang Wu, Anders Backlund and Yuan-Bin Cheng
Mar. Drugs 2016, 14(8), 151; https://doi.org/10.3390/md14080151 - 09 Aug 2016
Cited by 21 | Viewed by 7420
Abstract
A new marine ecdysteroid with an α-hydroxy group attaching at C-4 instead of attaching at C-2 and C-3, named palythone A (1), together with eight known compounds (29) were obtained from the ethanolic extract of the Formosan [...] Read more.
A new marine ecdysteroid with an α-hydroxy group attaching at C-4 instead of attaching at C-2 and C-3, named palythone A (1), together with eight known compounds (29) were obtained from the ethanolic extract of the Formosan zoanthid Palythoa mutuki. The structures of those compounds were mainly determined by NMR spectroscopic data analyses. The absolute configuration of 1 was further confirmed by comparing experimental and calculated circular dichroism (CD) spectra. Anti-dengue virus 2 activity and cytotoxicity of five isolated compounds were evaluated using virus infectious system and [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) assays, respectively. As a result, peridinin (9) exhibited strong antiviral activity (IC50 = 4.50 ± 0.46 μg/mL), which is better than that of the positive control, 2′CMC. It is the first carotene-like substance possessing anti-dengue virus activity. In addition, the structural diversity and bioactivity of the isolates were compared by using a ChemGPS–NP computational analysis. The ChemGPS–NP data suggested natural products with anti-dengue virus activity locate closely in the chemical space. Full article
(This article belongs to the Collection Bioactive Compounds from Marine Invertebrates)
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Article
Cubitanoids and Cembranoids from the Soft Coral Sinularia nanolobata
by Chih-Hua Chao, Chia-Yun Wu, Chiung-Yao Huang, Hui-Chun Wang, Chang-Feng Dai, Yang-Chang Wu and Jyh-Horng Sheu
Mar. Drugs 2016, 14(8), 150; https://doi.org/10.3390/md14080150 - 09 Aug 2016
Cited by 18 | Viewed by 5351
Abstract
Two new cubitanoids, nanoculones A and B (1 and 2), and three new cembranoids, nanolobols A–C (35), as well as six known compounds, calyculone I (6), sinulariuol A (7), sinulariols C, D, H, [...] Read more.
Two new cubitanoids, nanoculones A and B (1 and 2), and three new cembranoids, nanolobols A–C (35), as well as six known compounds, calyculone I (6), sinulariuol A (7), sinulariols C, D, H, and J (811), were isolated from the soft coral Sinularia nanolobata, collected off the coast of the eastern region of Taiwan. Their structures were elucidated on the basis of extensive spectroscopic analysis. Cytotoxicity of compounds 111 was evaluated. The nitric oxide (NO) inhibitory activity of selected compounds was further measured by assay of lipopolysaccharide (LPS)-stimulated NO production in activated RAW264.7 cells. The results showed that none of 111 exhibited cytotoxicity against the tested cancer cell lines, whereas compound 8 was found to significantly reduce NO production. Full article
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1861 KiB  
Article
The Algal Meroterpene 11-Hydroxy-1′-O-Methylamentadione Ameloriates Dextran Sulfate Sodium-Induced Colitis in Mice
by Hanaa Zbakh, Elena Talero, Javier Avila, Antonio Alcaide, Carolina De los Reyes, Eva Zubía and Virginia Motilva
Mar. Drugs 2016, 14(8), 149; https://doi.org/10.3390/md14080149 - 05 Aug 2016
Cited by 14 | Viewed by 6424
Abstract
Inflammatory bowel disease (IBD) is a complex class of immune disorders. Unfortunately, a treatment for total remission has not yet been found, while the use of natural product-based therapies has emerged as a promising intervention. The present study was aimed to investigate the [...] Read more.
Inflammatory bowel disease (IBD) is a complex class of immune disorders. Unfortunately, a treatment for total remission has not yet been found, while the use of natural product-based therapies has emerged as a promising intervention. The present study was aimed to investigate the anti-inflammatory effects of the algal meroterpene 11-hydroxy-1′-O-methylamentadione (AMT-E) in a murine model of dextran sodium sulphate (DSS)-induced colitis. AMT-E was orally administered daily (1, 10, and 20 mg/kg animal) to DSS treated mice (3% w/v) for 7 days. AMT-E prevented body weight loss and colon shortening and effectively attenuated the extent of the colonic damage. Similarly, AMT-E increased mucus production and reduced myeloperoxidase activity (marker for anti-inflammatory activity). Moreover, the algal meroterpene decreased the tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-10 levels, and caused a significant reduction of the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Our results demonstrate the protective effects of AMT-E on experimental colitis, provide an insight of the underlying mechanisms of this compound, and suggest that this class of marine natural products might be an interesting candidate for further studies on the prevention/treatment of IBD. Full article
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6152 KiB  
Review
Acetylated Triterpene Glycosides and Their Biological Activity from Holothuroidea Reported in the Past Six Decades
by Yadollah Bahrami and Christopher M. M. Franco
Mar. Drugs 2016, 14(8), 147; https://doi.org/10.3390/md14080147 - 04 Aug 2016
Cited by 53 | Viewed by 10474
Abstract
Sea cucumbers have been valued for many centuries as a tonic and functional food, dietary delicacies and important ingredients of traditional medicine in many Asian countries. An assortment of bioactive compounds has been described in sea cucumbers. The most important and abundant secondary [...] Read more.
Sea cucumbers have been valued for many centuries as a tonic and functional food, dietary delicacies and important ingredients of traditional medicine in many Asian countries. An assortment of bioactive compounds has been described in sea cucumbers. The most important and abundant secondary metabolites from sea cucumbers are triterpene glycosides (saponins). Due to the wide range of their potential biological activities, these natural compounds have gained attention and this has led to their emergence as high value compounds with extended application in nutraceutical, cosmeceutical, medicinal and pharmaceutical products. They are characterized by bearing a wide spectrum of structures, such as sulfated, non-sulfated and acetylated glycosides. Over 700 triterpene glycosides have been reported from the Holothuroidea in which more than 145 are decorated with an acetoxy group having 38 different aglycones. The majority of sea cucumber triterpene glycosides are of the holostane type containing a C18 (20) lactone group and either Δ7(8) or Δ9(11) double bond in their genins. The acetoxy group is mainly connected to the C-16, C-22, C-23 and/or C-25 of their aglycone. Apparently, the presence of an acetoxy group, particularly at C-16 of the aglycone, plays a significant role in the bioactivity; including induction of caspase, apoptosis, cytotoxicity, anticancer, antifungal and antibacterial activities of these compounds. This manuscript highlights the structure of acetylated saponins, their biological activity, and their structure-activity relationships. Full article
(This article belongs to the Collection Bioactive Compounds from Marine Invertebrates)
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3331 KiB  
Article
Undaria pinnatifida and Fucoxanthin Ameliorate Lipogenesis and Markers of Both Inflammation and Cardiovascular Dysfunction in an Animal Model of Diet-Induced Obesity
by Ameyalli Grasa-López, Ángel Miliar-García, Lucía Quevedo-Corona, Norma Paniagua-Castro, Gerardo Escalona-Cardoso, Elba Reyes-Maldonado and María-Eugenia Jaramillo-Flores
Mar. Drugs 2016, 14(8), 148; https://doi.org/10.3390/md14080148 - 03 Aug 2016
Cited by 77 | Viewed by 9759
Abstract
Brown algae and its carotenoids have been shown to have a positive influence on obesity and its comorbidities. This study evaluated the effect of Undaria pinnatifida and fucoxanthin on biochemical, physiological and inflammation markers related to obesity and on the expression of genes [...] Read more.
Brown algae and its carotenoids have been shown to have a positive influence on obesity and its comorbidities. This study evaluated the effect of Undaria pinnatifida and fucoxanthin on biochemical, physiological and inflammation markers related to obesity and on the expression of genes engaged on white adipose tissue lipid metabolism in a murine model of diet-induced obesity. The treatments improved energy expenditure, β-oxidation and adipogenesis by upregulating PPARα, PGC1α, PPARγ and UCP-1. Adipogenesis was also confirmed by image analysis of the retroperitoneal adipose tissue, by measuring cell area, perimeter and cellular density. Additionally, the treatments, ameliorated adipose tissue accumulation, insulin resistance, blood pressure, cholesterol and triglycerides concentration in serum, and reduced lipogenesis and inflammation by downregulating acetyl-CoA carboxylase (ACC) gene expression, increasing serum concentration and expression of adiponectin as well as downregulating IL-6 expression. Both fucoxanthin and Undaria pinnatifida may be considered for treating obesity and other diseases related. Full article
(This article belongs to the Special Issue Marine Natural Products that Target Metabolic Disorders)
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1716 KiB  
Article
Topsensterols A–C, Cytotoxic Polyhydroxylated Sterol Derivatives from a Marine Sponge Topsentia sp.
by Min Chen, Xu-Dong Wu, Qing Zhao and Chang-Yun Wang
Mar. Drugs 2016, 14(8), 146; https://doi.org/10.3390/md14080146 - 01 Aug 2016
Cited by 9 | Viewed by 6606
Abstract
Three new polyhydroxylated sterol derivatives topsensterols A–C (13) have been isolated from a marine sponge Topsentia sp. collected from the South China Sea. Their structures were elucidated by detailed analysis of the spectroscopic data, especially the NOESY spectra. Topsensterols [...] Read more.
Three new polyhydroxylated sterol derivatives topsensterols A–C (13) have been isolated from a marine sponge Topsentia sp. collected from the South China Sea. Their structures were elucidated by detailed analysis of the spectroscopic data, especially the NOESY spectra. Topsensterols A–C (l3) possess novel 2β,3α,4β,6α-tetrahydroxy-14α-methyl Δ9(11) steroidal nuclei with unusual side chains. Compound 2 exhibited cytotoxicity against human gastric carcinoma cell line SGC-7901 with an IC50 value of 8.0 μM. Compound 3 displayed cytotoxicity against human erythroleukemia cell line K562 with an IC50 value of 6.0 μM. Full article
(This article belongs to the Collection Bioactive Compounds from Marine Invertebrates)
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806 KiB  
Review
Fucoidans in Nanomedicine
by Lucas Chollet, Pierre Saboural, Cédric Chauvierre, Jean-Noël Villemin, Didier Letourneur and Frédéric Chaubet
Mar. Drugs 2016, 14(8), 145; https://doi.org/10.3390/md14080145 - 29 Jul 2016
Cited by 83 | Viewed by 11177
Abstract
Fucoidans are widespread cost-effective sulfated marine polysaccharides which have raised interest in the scientific community over last decades for their wide spectrum of bioactivities. Unsurprisingly, nanomedicine has grasped these compounds to develop innovative therapeutic and diagnostic nanosystems. The applications of fucoidans in nanomedicine [...] Read more.
Fucoidans are widespread cost-effective sulfated marine polysaccharides which have raised interest in the scientific community over last decades for their wide spectrum of bioactivities. Unsurprisingly, nanomedicine has grasped these compounds to develop innovative therapeutic and diagnostic nanosystems. The applications of fucoidans in nanomedicine as imaging agents, drug carriers or for their intrinsic properties are reviewed here after a short presentation of the main structural data and biological properties of fucoidans. The origin and the physicochemical specifications of fucoidans are summarized in order to discuss the strategy of fucoidan-containing nanosystems in Human health. Currently, there is a need for reproducible, well characterized fucoidan fractions to ensure significant progress. Full article
(This article belongs to the Collection Marine Polysaccharides)
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Article
High-EPA Biomass from Nannochloropsis salina Cultivated in a Flat-Panel Photo-Bioreactor on a Process Water-Enriched Growth Medium
by Hamed Safafar, Michael Z. Hass, Per Møller, Susan L. Holdt and Charlotte Jacobsen
Mar. Drugs 2016, 14(8), 144; https://doi.org/10.3390/md14080144 - 29 Jul 2016
Cited by 48 | Viewed by 8537
Abstract
Nannochloropsis salina was grown on a mixture of standard growth media and pre-gasified industrial process water representing effluent from a local biogas plant. The study aimed to investigate the effects of enriched growth media and cultivation time on nutritional composition of Nannochloropsis salina [...] Read more.
Nannochloropsis salina was grown on a mixture of standard growth media and pre-gasified industrial process water representing effluent from a local biogas plant. The study aimed to investigate the effects of enriched growth media and cultivation time on nutritional composition of Nannochloropsis salina biomass, with a focus on eicosapentaenoic acid (EPA). Variations in fatty acid composition, lipids, protein, amino acids, tocopherols and pigments were studied and results compared to algae cultivated on F/2 media as reference. Mixed growth media and process water enhanced the nutritional quality of Nannochloropsis salina in laboratory scale when compared to algae cultivated in standard F/2 medium. Data from laboratory scale translated to the large scale using a 4000 L flat panel photo-bioreactor system. The algae growth rate in winter conditions in Denmark was slow, but results revealed that large-scale cultivation of Nannochloropsis salina at these conditions could improve the nutritional properties such as EPA, tocopherol, protein and carotenoids compared to laboratory-scale cultivated microalgae. EPA reached 44.2% ± 2.30% of total fatty acids, and α-tocopherol reached 431 ± 28 µg/g of biomass dry weight after 21 days of cultivation. Variations in chemical compositions of Nannochloropsis salina were studied during the course of cultivation. Nannochloropsis salina can be presented as a good candidate for winter time cultivation in Denmark. The resulting biomass is a rich source of EPA and also a good source of protein (amino acids), tocopherols and carotenoids for potential use in aquaculture feed industry. Full article
(This article belongs to the Special Issue Marine Fatty Acids-2016)
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Article
5-Episinuleptolide Decreases the Expression of the Extracellular Matrix in Early Biofilm Formation of Multi-Drug Resistant Acinetobacter baumannii
by Sung-Pin Tseng, Wei-Chun Hung, Chiung-Yao Huang, Yin-Shiou Lin, Min-Yu Chan, Po-Liang Lu, Lin Lin and Jyh-Horng Sheu
Mar. Drugs 2016, 14(8), 143; https://doi.org/10.3390/md14080143 - 29 Jul 2016
Cited by 24 | Viewed by 6269
Abstract
Nosocomial infections and increasing multi-drug resistance caused by Acinetobacter baumannii have been recognized as emerging problems worldwide. Moreover, A. baumannii is able to colonize various abiotic materials and medical devices, making it difficult to eradicate and leading to ventilator-associated pneumonia, and bacteremia. Development [...] Read more.
Nosocomial infections and increasing multi-drug resistance caused by Acinetobacter baumannii have been recognized as emerging problems worldwide. Moreover, A. baumannii is able to colonize various abiotic materials and medical devices, making it difficult to eradicate and leading to ventilator-associated pneumonia, and bacteremia. Development of novel molecules that inhibit bacterial biofilm formation may be an alternative prophylactic option for the treatment of biofilm-associated A. baumannii infections. Marine environments, which are unlike their terrestrial counterparts, harbor an abundant biodiversity of marine organisms that produce novel bioactive natural products with pharmaceutical potential. In this study, we identified 5-episinuleptolide, which was isolated from Sinularia leptoclados, as an inhibitor of biofilm formation in ATCC 19606 and three multi-drug resistant A. baumannii strains. In addition, the anti-biofilm activities of 5-episinuleptolide were observed for Gram-negative bacteria but not for Gram-positive bacteria, indicating that the inhibition mechanism of 5-episinuleptolide is effective against only Gram-negative bacteria. The mechanism of biofilm inhibition was demonstrated to correlate to decreased gene expression from the pgaABCD locus, which encodes the extracellular polysaccharide poly-β-(1,6)-N-acetylglucosamine (PNAG). Scanning electron microscopy (SEM) indicated that extracellular matrix of the biofilm was dramatically decreased by treatment with 5-episinuleptolide. Our study showed potentially synergistic activity of combination therapy with 5-episinuleptolide and levofloxacin against biofilm formation and biofilm cells. These data indicate that inhibition of biofilm formation via 5-episinuleptolide may represent another prophylactic option for solving the persistent problem of biofilm-associated A. baumannii infections. Full article
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Article
Sinularin Induces Apoptosis through Mitochondria Dysfunction and Inactivation of the pI3K/Akt/mTOR Pathway in Gastric Carcinoma Cells
by Yu-Jen Wu, Bing-Sang Wong, Shu-Hao Yea, Chi-I Lu and Shun-Hsiang Weng
Mar. Drugs 2016, 14(8), 142; https://doi.org/10.3390/md14080142 - 27 Jul 2016
Cited by 43 | Viewed by 10871
Abstract
Sinularin is an active compound isolated from the cultured soft coral Sinularia flexibilis. In this study, we investigated the effects of sinularin on two human gastric cancer cell lines, AGS and NCI-N87. Our results demonstrated that sinularin suppressed the proliferation of gastric [...] Read more.
Sinularin is an active compound isolated from the cultured soft coral Sinularia flexibilis. In this study, we investigated the effects of sinularin on two human gastric cancer cell lines, AGS and NCI-N87. Our results demonstrated that sinularin suppressed the proliferation of gastric cancer cells in a dose-dependent manner and induced apoptosis. In addition, the loss of mitochondrial membrane potential, the release of cytochrome C, the activation of Bax, Bad and caspase-3/9, and the suppression of p-Bad, Bcl-xL and Bcl-2 were observed in the cells treated with sinularin. This finding suggests that sinularin-induced apoptosis is associated with mitochondria-mediated apoptosis and occurs through caspase-dependent pathways. Furthermore, sinularin inhibited the phosphoinositol 3-kinase/Akt/mechanistic target of the rapamycin signaling pathway. Taken together, our results show that sinularin-induced apoptosis is mediated by activation of the caspase cascade and mitochondrial dysfunction. Our findings suggest that sinularin merits further evaluation as a chemotherapeutic agent for human gastric cancer. Full article
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2072 KiB  
Review
Marine Natural Product Inhibitors of Neutrophil-Associated Inflammation
by Chun-Yu Chen, Yung-Fong Tsai, Wen-Yi Chang, Shun-Chin Yang and Tsong-Long Hwang
Mar. Drugs 2016, 14(8), 141; https://doi.org/10.3390/md14080141 - 26 Jul 2016
Cited by 5 | Viewed by 7385
Abstract
Neutrophils are widely recognized to play an important role in acute inflammatory responses, and recent evidence has expanded their role to modulating chronic inflammatory and autoimmune diseases. Reactive oxygen species (ROS) and microbicidal compounds released from neutrophils that are recruited to the site [...] Read more.
Neutrophils are widely recognized to play an important role in acute inflammatory responses, and recent evidence has expanded their role to modulating chronic inflammatory and autoimmune diseases. Reactive oxygen species (ROS) and microbicidal compounds released from neutrophils that are recruited to the site of inflammation contribute to the pathogenesis of multiple inflammation-associated diseases such as chronic obstructive pulmonary disease, atherosclerosis, and hepatitis. Marine organisms are a valuable source of bioactive compounds with potential for industrial and pharmaceutical application. Marine natural products that inhibit neutrophil activation could be used as drugs for the treatment of inflammatory diseases. Numerous studies investigating marine natural products have reported novel anti-inflammatory agents. Nevertheless, the detailed mechanisms underlying their actions, which could facilitate our understanding of the molecular events occurring in neutrophils, have not been reported in most of the associated research studies. Therefore, in this review, we will present marine products that inhibit neutrophil-associated inflammation. Furthermore, we will be limiting the detailed discussion to agents with well-investigated molecular targets. Full article
(This article belongs to the Special Issue Drug Design Based on Marine Natural Product Scaffolds)
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1442 KiB  
Article
Preparation of Chito-Oligomers by Hydrolysis of Chitosan in the Presence of Zeolite as Adsorbent
by Khalid A. Ibrahim, Bassam I. El-Eswed, Khaleel A. Abu-Sbeih, Tawfeeq A. Arafat, Mahmoud M. H. Al Omari, Fouad H. Darras and Adnan A. Badwan
Mar. Drugs 2016, 14(8), 43; https://doi.org/10.3390/md14080043 - 23 Jul 2016
Cited by 27 | Viewed by 6825
Abstract
An increasing interest has recently been shown to use chitin/chitosan oligomers (chito-oligomers) in medicine and food fields because they are not only water-soluble, nontoxic, and biocompatible materials, but they also exhibit numerous biological properties, including antibacterial, antifungal, and antitumor activities, as well as [...] Read more.
An increasing interest has recently been shown to use chitin/chitosan oligomers (chito-oligomers) in medicine and food fields because they are not only water-soluble, nontoxic, and biocompatible materials, but they also exhibit numerous biological properties, including antibacterial, antifungal, and antitumor activities, as well as immuno-enhancing effects on animals. Conventional depolymerization methods of chitosan to chito-oligomers are either chemical by acid-hydrolysis under harsh conditions or by enzymatic degradation. In this work, hydrolysis of chitosan to chito-oligomers has been achieved by applying adsorption-separation technique using diluted HCl in the presence of different types of zeolite as adsorbents. The chito-oligomers were retrieved from adsorbents and characterized by differential scanning calorimetry (DSC), liquid chromatography/mass spectroscopy (LC/MS), and ninhydrin test. Full article
(This article belongs to the Special Issue Advances in Marine Chitin and Chitosan II, 2017)
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32454 KiB  
Review
The Role of Spongia sp. in the Discovery of Marine Lead Compounds
by Patrícia Máximo, Luísa M. Ferreira, Paula Branco, Pedro Lima and Ana Lourenço
Mar. Drugs 2016, 14(8), 139; https://doi.org/10.3390/md14080139 - 23 Jul 2016
Cited by 20 | Viewed by 9355
Abstract
A comprehensive review on the chemistry of Spongia sp. is here presented, together with the biological activity of the isolated compounds. The compounds are grouped in sesquiterpene quinones, diterpenes, C21 and other linear furanoterpenes, sesterterpenes, sterols (including secosterols), macrolides and miscellaneous compounds. Among [...] Read more.
A comprehensive review on the chemistry of Spongia sp. is here presented, together with the biological activity of the isolated compounds. The compounds are grouped in sesquiterpene quinones, diterpenes, C21 and other linear furanoterpenes, sesterterpenes, sterols (including secosterols), macrolides and miscellaneous compounds. Among other reports we include studies on the intraspecific diversity of a Mediterranean species, compounds isolated from associated sponge and nudibranch and compounds isolated from S. zimocca and the red seaweed Laurentia microcladia. Under biological activity a table of the reported biological activities of the various compounds and the biological screening of extracts are described. The present review covers the literature from 1971 to 2015. Full article
(This article belongs to the Collection Bioactive Compounds from Marine Invertebrates)
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