Marine Drugs

Research

23 pages, 4978 KiB

Open AccessArticle

Antioxidant and Cytotoxic Effects on Tumor Cells of Exopolysaccharides from Tetraselmis suecica (Kylin) Butcher Grown Under Autotrophic and Heterotrophic Conditions

by Geovanna Parra-Riofrío, Jorge García-Márquez, Virginia Casas-Arrojo, Eduardo Uribe-Tapia and Roberto Teófilo Abdala-Díaz

Mar. Drugs 2020, 18(11), 534; https://doi.org/10.3390/md18110534 - 26 Oct 2020

Cited by 22 | Viewed by 3322

Abstract

Marine microalgae produce extracellular metabolites such as exopolysaccharides (EPS) with potentially beneficial biological applications to human health, especially antioxidant and antitumor properties, which can be increased with changes in crop trophic conditions. This study aimed to develop the autotrophic and heterotrophic culture of [...] Read more.

Marine microalgae produce extracellular metabolites such as exopolysaccharides (EPS) with potentially beneficial biological applications to human health, especially antioxidant and antitumor properties, which can be increased with changes in crop trophic conditions. This study aimed to develop the autotrophic and heterotrophic culture of Tetraselmis suecica (Kylin) Butcher in order to increase EPS production and to characterize its antioxidant activity and cytotoxic effects on tumor cells. The adaptation of autotrophic to heterotrophic culture was carried out by progressively reducing the photoperiod and adding glucose. EPS extraction and purification were performed. EPS were characterized by Fourier-transform infrared spectroscopy and gas chromatography-mass spectrometry. The antioxidant capacity of EPS was analyzed by the 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) method, and the antitumor capacity was measured by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, showing high activity on human leukemia, breast and lung cancer cell lines. Although total EPS showed no cytotoxicity, acidic EPS showed cytotoxicity over the gingival fibroblasts cell line. Heterotrophic culture has advantages over autotrophic, such as increasing EPS yield, higher antioxidant capacity of the EPS and, to the best of our knowledge, this is the first probe that T. suecica EPS have cytotoxic effects on tumor cells; therefore, they could offer greater advantages as possible natural nutraceuticals for the pharmaceutical industry. Full article

(This article belongs to the Special Issue Sulfur-Containing Marine Bioactives)

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17 pages, 2419 KiB

Open AccessArticle

One Step Forward towards the Development of Eco-Friendly Antifouling Coatings: Immobilization of a Sulfated Marine-Inspired Compound

by Cátia Vilas-Boas, Francisca Carvalhal, Beatriz Pereira, Sílvia Carvalho, Emília Sousa, Madalena M. M. Pinto, Maria José Calhorda, Vitor Vasconcelos, Joana R. Almeida, Elisabete R. Silva and Marta Correia-da-Silva

Mar. Drugs 2020, 18(10), 489; https://doi.org/10.3390/md18100489 - 25 Sep 2020

Cited by 17 | Viewed by 3319

Abstract

Marine biofouling represents a global economic and ecological challenge and few eco-friendly antifouling agents are available. The aim of this work was to establish the proof of concept that a recently synthesized nature-inspired compound (gallic acid persulfate, GAP) can act as an eco-friendly [...] Read more.

Marine biofouling represents a global economic and ecological challenge and few eco-friendly antifouling agents are available. The aim of this work was to establish the proof of concept that a recently synthesized nature-inspired compound (gallic acid persulfate, GAP) can act as an eco-friendly and effective antifoulant when immobilized in coatings through a non-release strategy, promoting a long-lasting antifouling effect. The synthesis of GAP was optimized to provide quantitative yields. GAP water solubility was assessed, showing values higher than 1000 mg/mL. GAP was found to be stable in sterilized natural seawater with a half-life (DT₅₀) of 7 months. GAP was immobilized into several commercial coatings, exhibiting high compatibility with different polymeric matrices. Leaching assays of polydimethylsiloxane and polyurethane-based marine coatings containing GAP confirmed that the chemical immobilization of GAP was successful, since releases up to fivefold lower than the conventional releasing systems of polyurethane-based marine coatings were observed. Furthermore, coatings containing immobilized GAP exhibited the most auspicious anti-settlement effect against Mytilus galloprovincialis larvae for the maximum exposure period (40 h) in laboratory trials. Overall, GAP promises to be an agent capable of improving the antifouling activity of several commercial marine coatings with desirable environmental properties. Full article

(This article belongs to the Special Issue Sulfur-Containing Marine Bioactives)

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18 pages, 2037 KiB

Open AccessFeature PaperArticle

Insights into the Light Response of Skeletonema marinoi: Involvement of Ovothiol

by Alfonsina Milito, Ida Orefice, Arianna Smerilli, Immacolata Castellano, Alessandra Napolitano, Christophe Brunet and Anna Palumbo

Mar. Drugs 2020, 18(9), 477; https://doi.org/10.3390/md18090477 - 20 Sep 2020

Cited by 14 | Viewed by 3373

Abstract

Diatoms are one of the most widespread groups of microalgae on Earth. They possess extraordinary metabolic capabilities, including a great ability to adapt to different light conditions. Recently, we have discovered that the diatom Skeletonema marinoi produces the natural antioxidant ovothiol B, until [...] Read more.

Diatoms are one of the most widespread groups of microalgae on Earth. They possess extraordinary metabolic capabilities, including a great ability to adapt to different light conditions. Recently, we have discovered that the diatom Skeletonema marinoi produces the natural antioxidant ovothiol B, until then identified only in clams. In this study, we investigated the light-dependent modulation of ovothiol biosynthesis in S. marinoi. Diatoms were exposed to different light conditions, ranging from prolonged darkness to low or high light, also differing in the velocity of intensity increase (sinusoidal versus square-wave distribution). The expression of the gene encoding the key ovothiol biosynthetic enzyme, ovoA, was upregulated by high sinusoidal light mimicking natural conditions. Under this situation higher levels of reactive oxygen species and nitric oxide as well as ovothiol and glutathione increase were detected. No ovoA modulation was observed under prolonged darkness nor low sinusoidal light. Unnatural conditions such as continuous square-wave light induced a very high oxidative stress leading to a drop in cell growth, without enhancing ovoA gene expression. Only one of the inducible forms of nitric oxide synthase, nos2, was upregulated by light with consequent production of NO under sinusoidal light and darkness conditions. Our data suggest that ovothiol biosynthesis is triggered by a combined light stress caused by natural distribution and increased photon flux density, with no influence from the daily light dose. These results open new perspectives for the biotechnological production of ovothiols, which are receiving a great interest for their biological activities in human model systems. Full article

(This article belongs to the Special Issue Sulfur-Containing Marine Bioactives)

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11 pages, 2677 KiB

Open AccessArticle

Preparation, Supramolecular Aggregation and Immunological Activity of the Bona Fide Vaccine Adjuvant Sulfavant S

by Emiliano Manzo, Laura Fioretto, Carmela Gallo, Marcello Ziaco, Genoveffa Nuzzo, Giuliana D’Ippolito, Assunta Borzacchiello, Antonio Fabozzi, Raffaele De Palma and Angelo Fontana

Mar. Drugs 2020, 18(9), 451; https://doi.org/10.3390/md18090451 - 29 Aug 2020

Cited by 8 | Viewed by 2472

Abstract

In aqueous conditions, amphiphilic bioactive molecules are able to form self-assembled colloidal structures modifying their biological activity. This behavior is generally neglected in preclinical studies, despite its impact on pharmacological development. In this regard, a significative example is represented by a new class [...] Read more.

In aqueous conditions, amphiphilic bioactive molecules are able to form self-assembled colloidal structures modifying their biological activity. This behavior is generally neglected in preclinical studies, despite its impact on pharmacological development. In this regard, a significative example is represented by a new class of amphiphilic marine-inspired vaccine adjuvants, collectively named Sulfavants, based on the β-sulfoquinovosyl-diacylglyceride skeleton. The family includes the lead product Sulfavant A (1) and two epimers, Sulfavant R (2) and Sulfavant S (3), differing only for the stereochemistry at C-2 of glycerol. The three compounds showed a significant difference in immunological potency, presumably correlated with change of the aggregates in water. Here, a new synthesis of diastereopure 3 was achieved, and the study of the immunomodulatory behavior of mixtures of 2/3 proved that the bizarre in vitro response to 1–3 effectively depends on the supramolecular aggregation states, likely affecting the bioavailability of agonists that can effectively interact with the cellular targets. The evidence obtained with the mixture of pure Sulfavant R (2) and Sulfavant S (3) proves, for the first time, that supramolecular organization of a mixture of active epimers in aqueous solution can bias evaluation of their biological and pharmacological potential. Full article

(This article belongs to the Special Issue Sulfur-Containing Marine Bioactives)

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13 pages, 2716 KiB

Open AccessArticle

Expression of Genes Related to Carrageenan Synthesis during Carposporogenesis of the Red Seaweed Grateloupia imbricata

by Pilar Garcia-Jimenez, Sara R. Mantesa and Rafael R. Robaina

Mar. Drugs 2020, 18(9), 432; https://doi.org/10.3390/md18090432 - 19 Aug 2020

Cited by 11 | Viewed by 2215

Abstract

Carrageenan, the foremost constituent of extracellular matrix of some rhodophyta, is a galactan backbone with a different number of sulphate groups attached. Variations of degree of sulphation are associated with different types of carrageenans, which vary according to seaweed life cycles, and have [...] Read more.

Carrageenan, the foremost constituent of extracellular matrix of some rhodophyta, is a galactan backbone with a different number of sulphate groups attached. Variations of degree of sulphation are associated with different types of carrageenans, which vary according to seaweed life cycles, and have consequences for the exploitation of this raw material. In this work, we used three well-recognised stages of development thalli and two stages of cystocarp maturation to analyse genes that encode addition and elimination of sulphate groups to cell-wall galactan of the red seaweed Grateloupia imbricata. Expressions of carbohydrate sulfotransferase and galactose-6 sulfurylase and genes encoding stress proteins such as cytochrome P450 and WD40, were examined. Results showed that transcript expression of carbohydrate sulfotransferase occurs at all stage of thalli development. Meanwhile galactose-6 sulfurylase expressions displayed different roles, which could be related to a temporal regulation of cystocarp maturation. Cytochrome P450 and WD40 are related to the disclosure and maturation of cystocarps of G. imbricata. Our conclusion is that differential expression of genes encoding proteins involved in the sulphation and desulphation of galactan backbone is associated with alterations in thalli development and cystocarp maturation in the red seaweed Grateloupia imbricata. Exploitation of industry-valued carrageenan will depend on insight into gene mechanisms of red seaweeds. Full article

(This article belongs to the Special Issue Sulfur-Containing Marine Bioactives)

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9 pages, 627 KiB

Open AccessArticle

Litoralimycins A and B, New Cytotoxic Thiopeptides from Streptomonospora sp. M2

by Shadi Khodamoradi, Marc Stadler, Joachim Wink and Frank Surup

Mar. Drugs 2020, 18(6), 280; https://doi.org/10.3390/md18060280 - 26 May 2020

Cited by 10 | Viewed by 2862

Abstract

Streptomonospora sp. M2 has been isolated from a soil sample collected at the Wadden Sea beach in our ongoing program aimed at the isolation of rare Actinobacteria, ultimately targeting the discovery of new antibiotics. Because crude extracts derived from cultures of this strain [...] Read more.

Streptomonospora sp. M2 has been isolated from a soil sample collected at the Wadden Sea beach in our ongoing program aimed at the isolation of rare Actinobacteria, ultimately targeting the discovery of new antibiotics. Because crude extracts derived from cultures of this strain showed inhibitory activity against the indicator organism Bacillus subtilis, it was selected for further analysis. HPLC–MS analysis of its culture broth revealed the presence of lipophilic metabolites. The two major metabolites of those were isolated by preparative reversed-phase HPLC and preparative TLC. Their planar structures were elucidated using high-resolution electrospray ionization mass spectrometry (HRESIMS), 1D and 2D NMR data as new thiopeptide antibiotics and named litoralimycin A (1) and B (2). Although rotating frame nuclear Overhauser effect spectroscopy (ROESY) data established a Z configuration of the Δ^21,26 double bond, the stereochemistry of C-5 and C-15 were assigned as S by Marfey’s method after ozonolysis. The biological activity spectrum of 1 and 2 is highly uncommon for thiopeptide antibiotics, since they showed only insignificant antibacterial activity, but 1 showed strong cytotoxic effects. Full article

(This article belongs to the Special Issue Sulfur-Containing Marine Bioactives)

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14 pages, 2400 KiB

Open AccessArticle

Effects of Sulfated Fucans from Laminaria hyperborea Regarding VEGF Secretion, Cell Viability, and Oxidative Stress and Correlation with Molecular Weight

by Philipp Dörschmann, Georg Kopplin, Johann Roider and Alexa Klettner

Mar. Drugs 2019, 17(10), 548; https://doi.org/10.3390/md17100548 - 25 Sep 2019

Cited by 20 | Viewed by 3635

Abstract

Background: Sulfated fucans show interesting effects in the treatment of ocular diseases (e.g., age-related macular degeneration), depending on their chemical structure. Here, we compared three purified sulfated fucans from Laminaria hyperborea (LH) regarding cell viability, oxidative stress protection, and vascular endothelial growth factor [...] Read more.

Background: Sulfated fucans show interesting effects in the treatment of ocular diseases (e.g., age-related macular degeneration), depending on their chemical structure. Here, we compared three purified sulfated fucans from Laminaria hyperborea (LH) regarding cell viability, oxidative stress protection, and vascular endothelial growth factor (VEGF) secretion in ocular cells. Methods: High-molecular-weight sulfated fucan (M_w = 1548.6 kDa, Fuc1) was extracted with warm water and purified through ultrafiltration. Lower-molecular-weight samples (M_w = 499 kDa, Fuc2; 26.9 kDa, Fuc3) were obtained by mild acid hydrolysis of ultrapurified sulfated fucan and analyzed (SEC-MALS (Size-exclusion chromatography-Multi-Angle Light Scattering), ICP-MS, and GC). Concentrations between 1 and 100 µg/mL were tested. Cell viability was measured after 24 h (uveal melanoma cell line (OMM-1), retinal pigment epithelium (RPE) cell line ARPE-19, primary RPE cells) via MTT/MTS (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide/3-(4,5-Dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay. Oxidative stress protection was determined after 24 h (OMM-1, ARPE-19). VEGF secretion was analyzed via ELISA after three days (ARPE-19, RPE). Results: Fuc2 and Fuc3 were antiproliferative for OMM-1, but not for ARPE. Fuc1 protected OMM-1. VEGF secretion was lowered with all fucans except Fuc3 in ARPE-19 and RPE. The results suggest a correlation between molecular weight and biological activity, with efficiency increasing with size. Conclusion: The LH sulfated fucan Fuc1 showed promising results regarding VEGF inhibition and protection, encouraging further medical research. Full article

(This article belongs to the Special Issue Sulfur-Containing Marine Bioactives)

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17 pages, 11825 KiB

Open AccessArticle

The Inhibitory Effect of Propylene Glycol Alginate Sodium Sulfate on Fibroblast Growth Factor 2-Mediated Angiogenesis and Invasion in Murine Melanoma B16-F10 Cells In Vitro

by He Ma, Peiju Qiu, Huixin Xu, Ximing Xu, Meng Xin, Yanyan Chu, Huashi Guan, Chunxia Li and Jinbo Yang

Mar. Drugs 2019, 17(5), 257; https://doi.org/10.3390/md17050257 - 29 Apr 2019

Cited by 7 | Viewed by 3325

Abstract

Melanoma is one of the most malignant and aggressive types of cancer worldwide. Fibroblast growth factor 2 (FGF2) is one of the critical regulators of melanoma angiogenesis and metastasis; thus, it might be an effective anti-cancer strategy to explore FGF2-targeting drug candidates from [...] Read more.

Melanoma is one of the most malignant and aggressive types of cancer worldwide. Fibroblast growth factor 2 (FGF2) is one of the critical regulators of melanoma angiogenesis and metastasis; thus, it might be an effective anti-cancer strategy to explore FGF2-targeting drug candidates from existing drugs. In this study, we evaluate the effect of the marine drug propylene glycol alginate sodium sulfate (PSS) on FGF2-mediated angiogenesis and invasion. The data shows that FGF2 selectively bound to PSS with high affinity. PSS inhibited FGF2-mediated angiogenesis in a rat aortic ring model and suppressed FGF2-mediated invasion, but not the migration of murine melanoma B16-F10 cells. The further mechanism study indicates that PSS decreased the expression of activated matrix metalloproteinase 2 (MMP-2) and matrix metalloproteinase 9 (MMP-9), and also suppressed their activity. In addition, PSS was found to decrease the level of Vimentin in B16-F10 cells, which is known to participate in the epithelial–mesenchymal transition. Notably, PSS did not elicit any changes in cancer cell viability. Based on the results above, we conclude that PSS might be a potential drug to regulate the tumor microenvironment in order to facilitate the recovery of melanoma patients. Full article

(This article belongs to the Special Issue Sulfur-Containing Marine Bioactives)

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