Marine Drugs

13 pages, 1225 KiB

Open AccessArticle

Analysis of Structural Determinants of Peptide MS 9a-1 Essential for Potentiating of TRPA1 Channel

by Yulia A. Logashina, Kseniya I. Lubova, Ekaterina E. Maleeva, Viktor A. Palikov, Yulia A. Palikova, Igor A. Dyachenko and Yaroslav A. Andreev

Mar. Drugs 2022, 20(7), 465; https://doi.org/10.3390/md20070465 - 21 Jul 2022

Cited by 4 | Viewed by 2149

Abstract

The TRPA1 channel is involved in a variety of physiological processes and its activation leads to pain perception and the development of inflammation. Peptide Ms 9a-1 from sea anemone Metridium senile is a positive modulator of TRPA1 and causes significant analgesic and anti-inflammatory [...] Read more.

The TRPA1 channel is involved in a variety of physiological processes and its activation leads to pain perception and the development of inflammation. Peptide Ms 9a-1 from sea anemone Metridium senile is a positive modulator of TRPA1 and causes significant analgesic and anti-inflammatory effects by desensitization of TRPA1-expressing sensory neurons. For structural and functional analysis of Ms 9a-1, we produced four peptides—Ms 9a-1 without C-terminal domain (abbreviated as N-Ms), short C-terminal domain Ms 9a-1 alone (C-Ms), and two homologous peptides (Ms 9a-2 and Ms 9a-3). All tested peptides possessed a reduced potentiating effect on TRPA1 compared to Ms 9a-1 in vitro. None of the peptides reproduced analgesic and anti-inflammatory properties of Ms 9a-1 in vivo. Peptides N-Ms and C-Ms were able to reduce pain induced by AITC (selective TRPA1 agonist) but did not decrease AITC-induced paw edema development. Fragments of Ms 9a-1 did not effectively reverse CFA-induced thermal hyperalgesia and paw edema. Ms 9a-2 and Ms 9a-3 possessed significant effects and anti-inflammatory properties in some doses, but their unexpected efficacy and bell-shape dose–responses support the hypothesis of other targets involved in their effects in vivo. Therefore, activity comparison of Ms 9a-1 fragments and homologues peptides revealed structural determinants important for TRPA1 modulation, as well as analgesic and anti-inflammatory properties of Ms9a-1. Full article

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8 pages, 633 KiB

Open AccessArticle

New Glycosylated Secondary Metabolites from Marine-Derived Bacteria

by Cao Van Anh, Jong Soon Kang, Hwa-Sun Lee, Phan Thi Hoai Trinh, Chang-Su Heo and Hee Jae Shin

Mar. Drugs 2022, 20(7), 464; https://doi.org/10.3390/md20070464 - 20 Jul 2022

Cited by 4 | Viewed by 2458

Abstract

Three new glycosylated secondary metabolites, including a new indole alkaloid, pityriacitrin D (1), and two new trehalose lipids (2 and 3), together with three known compounds (4–6) were isolated from two marine-derived bacterial strains, Bacillus [...] Read more.

Three new glycosylated secondary metabolites, including a new indole alkaloid, pityriacitrin D (1), and two new trehalose lipids (2 and 3), together with three known compounds (4–6) were isolated from two marine-derived bacterial strains, Bacillus siamensis 168CLC-66.1 and Tsukamurella pseudospumae IV19-045. The structures of 1–3 were determined by extensive analysis and comparison of their spectroscopic data with literature values. The absolute configurations of sugar moieties were determined by chemical derivatization followed by LC-MS analysis. Cytotoxicity of 1–3 against six cancer cell lines was evaluated by SRB assay, and 1 showed moderate activity against all the tested cell lines with GI₅₀ values ranging from 8.0 to 10.9 µM. Full article

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22 pages, 3112 KiB

Open AccessArticle

Exploring the Antibiotic Production Potential of Heterotrophic Bacterial Communities Isolated from the Marine Sponges Crateromorpha meyeri, Pseudaxinella reticulata, Farrea similaris, and Caulophacus arcticus through Synergistic Metabolomic and Genomic Analyses

by Sanaullah Tareen, Peter J. Schupp, Naveed Iqbal and Joachim Wink

Mar. Drugs 2022, 20(7), 463; https://doi.org/10.3390/md20070463 - 20 Jul 2022

Cited by 2 | Viewed by 2840

Abstract

The discovery of novel secondary metabolites is actively being pursued in new ecosystems. Sponge-associated bacteria have been in the limelight in recent years on account of their ability to produce bioactive compounds. In this study, heterotrophic bacteria associated with four sponge species were [...] Read more.

The discovery of novel secondary metabolites is actively being pursued in new ecosystems. Sponge-associated bacteria have been in the limelight in recent years on account of their ability to produce bioactive compounds. In this study, heterotrophic bacteria associated with four sponge species were isolated, taxonomically identified, and subjected to screening for the production of bioactive entities against a panel of nine microorganisms, including Gram-positive and negative bacteria, as well as yeast and fungi. Of the 105 isolated strains, 66% were represented by Proteobacteria, 16% by Bacteriodetes, 7% by Actinobacteria, and 11% by Firmicutes. Bioactivity screening revealed that 40% of the total isolated strains showed antimicrobial activity against one or more of the target microorganisms tested. Further, active extracts from selective species were narrowed down by bioassay-guided fractionation and subsequently identified by HR-ESI-MS analyses to locate the active peaks. Presumably responsible compounds for the observed bioactivities were identified as pentadecenoic acid, oleic acid, and palmitoleic acid. One isolate, Qipengyuania pacifica NZ-96^T, based on 16S rRNA novelty, was subjected to comparative metabolic reconstruction analysis with its closest phylogenetic neighbors, revealing 79 unique functional roles in the novel isolate. In addition, genome mining of Qipengyuania pacifica NZ-96^T revealed three biosynthetic gene clusters responsible for the biosynthesis of terpene, beta lactone, lasso peptide, and hserlactone secondary metabolites. Our results demonstrate the ability to target the sponge microbiome as a potential source of novel microbial life with biotechnological potential. Full article

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17 pages, 4036 KiB

Open AccessArticle

Connection of Isolated Stereoclusters by Combining ¹³C-RCSA, RDC, and J-Based Configurational Analyses and Structural Revision of a Tetraprenyltoluquinol Chromane Meroterpenoid from Sargassum muticum

by Juan Carlos C. Fuentes-Monteverde, Nilamoni Nath, Abel M. Forero, Elena M. Balboa, Armando Navarro-Vázquez, Christian Griesinger, Carlos Jiménez and Jaime Rodríguez

Mar. Drugs 2022, 20(7), 462; https://doi.org/10.3390/md20070462 - 18 Jul 2022

Cited by 3 | Viewed by 2916

Abstract

The seaweed Sargassum muticum, collected on the southern coast of Galicia, yielded a tetraprenyltoluquinol chromane meroditerpene compound known as 1b, whose structure is revised. The relative configuration of 1b was determined by J-based configurational methodology combined with an iJ [...] Read more.

The seaweed Sargassum muticum, collected on the southern coast of Galicia, yielded a tetraprenyltoluquinol chromane meroditerpene compound known as 1b, whose structure is revised. The relative configuration of 1b was determined by J-based configurational methodology combined with an iJ/DP4 statistical analysis and further confirmed by measuring two anisotropic properties: carbon residual chemical shift anisotropies (¹³C-RCSAs) and one-bond ¹H-¹³C residual dipolar couplings (¹D_CH-RDCs). The absolute configuration of 1b was deduced by ECD/OR/TD-DFT methods and established as 3R,7S,11R. Full article

(This article belongs to the Special Issue Marine Drugs Research in Spain)

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23 pages, 4789 KiB

Open AccessArticle

First Characterization of Ostreopsis cf. ovata (Dinophyceae) and Detection of Ovatoxins during a Multispecific and Toxic Ostreopsis Bloom on French Atlantic Coast

by Nicolas Chomérat, Elvire Antajan, Isabelle Auby, Gwenael Bilien, Liliane Carpentier, Marie-Noëlle de Casamajor, Florian Ganthy, Fabienne Hervé, Magali Labadie, Claire Méteigner, Camille Paradis, Myriam Perrière-Rumèbe, Florence Sanchez, Véronique Séchet and Zouher Amzil

Mar. Drugs 2022, 20(7), 461; https://doi.org/10.3390/md20070461 - 18 Jul 2022

Cited by 22 | Viewed by 4182

Abstract

Blooms of the benthic toxic dinoflagellate genus Ostreopsis have been recorded more frequently during the last two decades, particularly in warm temperate areas such as the Mediterranean Sea. The proliferation of Ostreopsis species may cause deleterious effects on ecosystems and can impact human [...] Read more.

Blooms of the benthic toxic dinoflagellate genus Ostreopsis have been recorded more frequently during the last two decades, particularly in warm temperate areas such as the Mediterranean Sea. The proliferation of Ostreopsis species may cause deleterious effects on ecosystems and can impact human health through skin contact or aerosol inhalation. In the eastern Atlantic Ocean, the toxic O. cf. ovata has not yet been reported to the north of Portugal, and the only species present further north was O. cf. siamensis, for which the toxic risk is considered low. During summer blooms of unidentified Ostreopsis species on the French Basque coast (Atlantic) in 2020 and 2021, people suffered from irritations and respiratory disorders, and the number of analyzed cases reached 674 in 2021. In order to investigate the causes, sampling was carried out during summer 2021 to (i) taxonomically identify Ostreopsis species present using a molecular approach, (ii) isolate strains from the bloom and culture them, and (iii) characterize the presence of known toxins which may be involved. For the first time, this study reports the presence of both O. cf. siamensis and O. cf. ovata, for which the French Basque coast is a new upper distribution limit. Furthermore, the presence of ovatoxins a, b, c, and d in the environmental sample and in a cultivated strain in culture confirmed the toxic nature of the bloom and allowed identifying O. cf. ovata as the producer. The present data identify a new health risk in the area and highlight the extended distribution of some harmful dinoflagellates, presumably in relation to climate change. Full article

(This article belongs to the Special Issue Marine Biotoxins 2.0)

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13 pages, 2518 KiB

Open AccessReview

Chitin and Chitosan: Prospective Biomedical Applications in Drug Delivery, Cancer Treatment, and Wound Healing

by Parnian Baharlouei and Azizur Rahman

Mar. Drugs 2022, 20(7), 460; https://doi.org/10.3390/md20070460 - 17 Jul 2022

Cited by 104 | Viewed by 8579

Abstract

Chitin and its derivative chitosan are highly abundant polymers in nature, appearing in both the shells and exoskeletons of various marine and non-marine species. Since they possess favorable properties, such as biocompatibility, biodegradability, non-toxicity, and non-immunogenicity, they have gained recent attention due to [...] Read more.

Chitin and its derivative chitosan are highly abundant polymers in nature, appearing in both the shells and exoskeletons of various marine and non-marine species. Since they possess favorable properties, such as biocompatibility, biodegradability, non-toxicity, and non-immunogenicity, they have gained recent attention due to their enormous potential biomedical applications. The polycationic surface of chitosan enables it to form hydrogenic and ionic bonds with drug molecules, which is one of its most useful properties. Because chitosan is biocompatible, it can therefore be used in drug delivery systems. The development of chitosan-based nanoparticles has also contributed to the significance of chitin as a drug delivery system that can deliver drugs topically. Furthermore, chitin can be used in cancer treatment as a vehicle for delivering cancer drugs to a specific site and has an antiproliferative effect by reducing the viability of cells. Finally, chitosan can be used as a wound dressing in order to promote the faster regeneration of skin epithelial cells and collagen production by fibroblasts. As discussed in this review, chitin and chitosan have diverse applications in the medical field. Recognizing the biomedical applications of these two polymers is essential for future research in tissue engineering and nanobiotechnology. Full article

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16 pages, 6655 KiB

Open AccessArticle

Functional Characterization, Antimicrobial Effects, and Potential Antibacterial Mechanisms of NpHM4, a Derived Peptide of Nautilus pompilius Hemocyanin

by Chun Yuan, Xiaoying Zheng, Kunna Liu, Wenbin Yuan, Yang Zhang, Fan Mao and Yongbo Bao

Mar. Drugs 2022, 20(7), 459; https://doi.org/10.3390/md20070459 - 16 Jul 2022

Cited by 6 | Viewed by 2323

Abstract

Hemocyanins present in the hemolymph of invertebrates are multifunctional proteins that are responsible for oxygen transport and play crucial roles in the immune system. They have also been identified as a source of antimicrobial peptides during infection in mollusks. Hemocyanin has also been [...] Read more.

Hemocyanins present in the hemolymph of invertebrates are multifunctional proteins that are responsible for oxygen transport and play crucial roles in the immune system. They have also been identified as a source of antimicrobial peptides during infection in mollusks. Hemocyanin has also been identified in the cephalopod ancestor Nautilus, but antimicrobial peptides derived from the hemocyanin of Nautilus pompilius have not been reported. Here, the bactericidal activity of six predicted peptides from N. pompilius hemocyanin and seven mutant peptides was analyzed. Among those peptides, a mutant peptide with 15 amino acids (1RVFAGFLRHGIKRSR15), NpHM4, showed relatively high antibacterial activity. NpHM4 was determined to have typical antimicrobial peptide characteristics, including a positive charge (+5.25) and a high hydrophobic residue ratio (40%), and it was predicted to form an alpha-helical structure. In addition, NpHM4 exhibited significant antibacterial activity against Gram-negative bacteria (MBC = 30 μM for Vibrio alginolyticus), with no cytotoxicity to mammalian cells even at a high concentration of 180 µM. Upon contact with V. alginolyticus cells, we confirmed that the bactericidal activity of NpHM4 was coupled with membrane permeabilization, which was further confirmed via ultrastructural images using a scanning electron microscope. Therefore, our study provides a rationalization for the development and optimization of antimicrobial peptide from the cephalopod ancestor Nautilus, paving the way for future novel AMP development with broad applications. Full article

(This article belongs to the Special Issue Marine Antimicrobial Peptides and Marine Compounds for Fighting Antimicrobial Resistance)

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18 pages, 2535 KiB

Open AccessArticle

Sulfated Polysaccharide Extracted from the Green Algae Codium bernabei: Physicochemical Characterization and Antioxidant, Anticoagulant and Antitumor Activity

by Fabian A. Figueroa, Roberto T. Abdala-Díaz, Claudia Pérez, Virginia Casas-Arrojo, Aleksandra Nesic, Cecilia Tapia, Carla Durán, Oscar Valdes, Carolina Parra, Gastón Bravo-Arrepol, Luis Soto, José Becerra and Gustavo Cabrera-Barjas

Mar. Drugs 2022, 20(7), 458; https://doi.org/10.3390/md20070458 - 15 Jul 2022

Cited by 34 | Viewed by 4513

Abstract

Codium bernabei is a green alga that grows on Chilean coasts. The composition of its structural polysaccharides is still unknown. Hence, the aim of this work is to isolate and characterize the hot water extracted polysaccharide fractions. For this purpose, the water extracts [...] Read more.

Codium bernabei is a green alga that grows on Chilean coasts. The composition of its structural polysaccharides is still unknown. Hence, the aim of this work is to isolate and characterize the hot water extracted polysaccharide fractions. For this purpose, the water extracts were further precipitated in alcohol (TPs) and acid media (APs), respectively. Both fractions were characterized using different physicochemical techniques such as GC-MS, GPC, FTIR, TGA, and SEM. It is confirmed that the extracted fractions are mainly made of sulfated galactan unit, with a degree of sulfation of 19.3% (TPs) and 17.4% (ATs) and a protein content of 3.5% in APs and 15.6% in TPs. Other neutral sugars such as xylose, glucose, galactose, fucose, mannose, and arabinose were found in a molar ratio (0.05:0.6:1.0:0.02:0.14:0.11) for TPs and (0.05:0.31:1.0:0.03:0.1:0.13) for ATs. The molecular weight of the polysaccharide samples was lower than 20 kDa. Both polysaccharides were thermally stable (Tonset > 190 °C) and showed antioxidant activity according to the ABTS^•+ and DPPH tests, where TPs fractions had higher scavenging activity (35%) compared to the APs fractions. The PT and APTTS assays were used to measure the anticoagulant activity of the polysaccharide fractions. In general, the PT activity of the TPs and APs was not different from normal plasma values. The exception was the TPs treatment at 1000 µg mL⁻¹ concentration. The APTTS test revealed that clotting time for both polysaccharides was prolonged regarding normal values at 1000 µg mL⁻¹. Finally, the antitumor test in colorectal carcinoma (HTC-116) cell line, breast cancer (MCF-7) and human leukemia (HL-60) cell lines showed the cytotoxic effect of TPs and APs. Those results suggest the potential biotechnological application of sulfate galactan polysaccharides isolated from a Chilean marine resource. Full article

(This article belongs to the Section Marine-Derived Ingredients for Drugs, Cosmeceuticals and Nutraceuticals)

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13 pages, 1939 KiB

Open AccessArticle

Glucose Uptake and Oxidative Stress in Caco-2 Cells: Health Benefits from Posidonia oceanica (L.) Delile

by Camilla Morresi, Marzia Vasarri, Luisa Bellachioma, Gianna Ferretti, Donatella Degl′Innocenti and Tiziana Bacchetti

Mar. Drugs 2022, 20(7), 457; https://doi.org/10.3390/md20070457 - 14 Jul 2022

Cited by 7 | Viewed by 3239

Abstract

Posidonia oceanica (L.) Delile is an endemic Mediterranean marine plant of extreme ecological importance. Previous in vitro and in vivo studies have demonstrated the potential antidiabetic properties of P. oceanica leaf extract. Intestinal glucose transporters play a key role in glucose homeostasis and [...] Read more.

Posidonia oceanica (L.) Delile is an endemic Mediterranean marine plant of extreme ecological importance. Previous in vitro and in vivo studies have demonstrated the potential antidiabetic properties of P. oceanica leaf extract. Intestinal glucose transporters play a key role in glucose homeostasis and represent novel targets for the management of diabetes. In this study, the ability of a hydroalcoholic P. oceanica leaf extract (POE) to modulate intestinal glucose transporters was investigated using Caco-2 cells as a model of an intestinal barrier. The incubation of cells with POE significantly decreased glucose uptake by decreasing the GLUT2 glucose transporter levels. Moreover, POE had a positive effect on the barrier integrity by increasing the Zonulin-1 levels. A protective effect exerted by POE against oxidative stress induced by chronic exposure to high glucose concentrations or tert-butyl hydroperoxide was also demonstrated. This study highlights for the first time the effect of POE on glucose transport, intestinal barrier integrity, and its protective antioxidant effect in Caco-2 cells. These findings suggest that the P. oceanica phytocomplex may have a positive impact by preventing the intestinal cell dysfunction involved in the development of inflammation-related disease associated with oxidative stress. Full article

(This article belongs to the Special Issue Marine Anti-inflammatory and Antioxidant Agents 2.0)

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12 pages, 2571 KiB

Open AccessArticle

New Insights into Xanthophylls and Lipidomic Profile Changes Induced by Glucose Supplementation in the Marine Diatom Nitzschia laevis

by Xuemei Mao, Xia Wang, Mengdie Ge, Feng Chen and Bin Liu

Mar. Drugs 2022, 20(7), 456; https://doi.org/10.3390/md20070456 - 14 Jul 2022

Cited by 5 | Viewed by 2108

Abstract

Nitzschia laevis is a candidate microorganism for bioactive compounds (fucoxanthin and eicosapentaenoic acid (EPA)) production. In this study, the impacts of glucose-induced trophic transition on biomass, photosynthesis, pigments, and lipid profiles were examined. The specific growth rate was increased under glucose addition, achieved [...] Read more.

Nitzschia laevis is a candidate microorganism for bioactive compounds (fucoxanthin and eicosapentaenoic acid (EPA)) production. In this study, the impacts of glucose-induced trophic transition on biomass, photosynthesis, pigments, and lipid profiles were examined. The specific growth rate was increased under glucose addition, achieved at 0.47 day⁻¹ (0.26 ± 0.01 day⁻¹ for the group without glucose in medium). However, the photosynthetic parameters and pigments including chlorophylls, fucoxanthin, and diatoxanthin were reduced. The net yield of EPA doubled under glucose addition, reaching 20.36 ± 1.22 mg/L in 4 days. In addition, the alteration in detailed lipid molecular species was demonstrated with a focus on EPA-enriched lipids. The effects of 2-deoxyglucose (2DG) indicated that glucose phosphorylation was involved in glucose-induced regulation. These findings provide novel data for guiding the application of this diatom strain in the functional food industries. Full article

(This article belongs to the Special Issue Marine Microalgal Functional Foods)

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19 pages, 3405 KiB

Open AccessArticle

Epoxinnamide: An Epoxy Cinnamoyl-Containing Nonribosomal Peptide from an Intertidal Mudflat-Derived Streptomyces sp.

by Sangwook Kang, Jaeho Han, Sung Chul Jang, Joon Soo An, Ilnam Kang, Yun Kwon, Sang-Jip Nam, Sang Hee Shim, Jang-Cheon Cho, Sang Kook Lee and Dong-Chan Oh

Mar. Drugs 2022, 20(7), 455; https://doi.org/10.3390/md20070455 - 12 Jul 2022

Cited by 9 | Viewed by 3638

Abstract

Cinnamoyl-containing nonribosomal peptides (CCNPs) form a unique family of actinobacterial secondary metabolites and display various biological activities. A new CCNP named epoxinnamide (1) was discovered from intertidal mudflat-derived Streptomyces sp. OID44. The structure of 1 was determined by the analysis of [...] Read more.

Cinnamoyl-containing nonribosomal peptides (CCNPs) form a unique family of actinobacterial secondary metabolites and display various biological activities. A new CCNP named epoxinnamide (1) was discovered from intertidal mudflat-derived Streptomyces sp. OID44. The structure of 1 was determined by the analysis of one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) data along with a mass spectrum. The absolute configuration of 1 was assigned by the combination of advanced Marfey’s method, ³J_HH and rotating-frame overhauser effect spectroscopy (ROESY) analysis, DP4 calculation, and genomic analysis. The putative biosynthetic pathway of epoxinnamide (1) was identified through the whole-genome sequencing of Streptomyces sp. OID44. In particular, the thioesterase domain in the nonribosomal peptide synthetase (NRPS) biosynthetic gene cluster was proposed as a bifunctional enzyme, which catalyzes both epimerization and macrocyclization. Epoxinnamide (1) induced quinone reductase (QR) activity in murine Hepa-1c1c7 cells by 1.6-fold at 5 μM. It also exhibited effective antiangiogenesis activity in human umbilical vein endothelial cells (IC₅₀ = 13.4 μM). Full article

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10 pages, 8164 KiB

Open AccessArticle

A Series of New Pyrrole Alkaloids with ALR2 Inhibitory Activities from the Sponge Stylissa massa

by Qi Wang, Chunhua Gao, Zhun Wei, Xiaowen Tang, Lixia Ji, Xiangchao Luo, Xiaoping Peng, Gang Li and Hongxiang Lou

Mar. Drugs 2022, 20(7), 454; https://doi.org/10.3390/md20070454 - 12 Jul 2022

Cited by 8 | Viewed by 2249

Abstract

Twelve new and four known alkaloids including five different structural scaffolds were isolated from the sponge Stylissa massa collected in the South China Sea. Compound 1 is the first identified precursor metabolite of the classic 5/7/5 tricyclic skeleton with unesterified guanidine and carboxyl [...] Read more.

Twelve new and four known alkaloids including five different structural scaffolds were isolated from the sponge Stylissa massa collected in the South China Sea. Compound 1 is the first identified precursor metabolite of the classic 5/7/5 tricyclic skeleton with unesterified guanidine and carboxyl groups, compounds 2–5 and 13–15 belong to the spongiacidin-type pyrrole imidazole alkaloids (PIAs). Z- and E-configurations of the spongiacidin-type PIAs often appeared concomitantly and were distinguished by the chemical shift analysis of ¹³C NMR spectra. The structures of all twelve new compounds were determined by NMR, MS, and ECD analysis combined with single-crystal data of compounds 1, 5, and 10. In the aldose reductase (ALR2) inhibitory assay, six 5/7/5 tricyclic compounds (2–5, 13–15) displayed significant activities. Compounds 13 and 14, as the representative members of spongiacidin-PIAs, demonstrated their ALR2-targeted activities in SPR experiments with K_D values of 12.5 and 6.9 µM, respectively. Full article

(This article belongs to the Special Issue Heterocyclic Compounds from Marine Organisms)

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31 pages, 2494 KiB

Open AccessArticle

Structural Characterization of Maitotoxins Produced by Toxic Gambierdiscus Species

by J. Sam Murray, Sarah C. Finch, Elizabeth M. Mudge, Alistair L. Wilkins, Jonathan Puddick, D. Tim Harwood, Lesley L. Rhodes, Roel van Ginkel, Frode Rise and Michèle R. Prinsep

Mar. Drugs 2022, 20(7), 453; https://doi.org/10.3390/md20070453 - 12 Jul 2022

Cited by 8 | Viewed by 4477

Abstract

Identifying compounds responsible for the observed toxicity of the Gambierdiscus species is a critical step to ascertaining whether they contribute to ciguatera poisoning. Macroalgae samples were collected during research expeditions to Rarotonga (Cook Islands) and North Meyer Island (Kermadec Islands), from which two [...] Read more.

Identifying compounds responsible for the observed toxicity of the Gambierdiscus species is a critical step to ascertaining whether they contribute to ciguatera poisoning. Macroalgae samples were collected during research expeditions to Rarotonga (Cook Islands) and North Meyer Island (Kermadec Islands), from which two new Gambierdiscus species were characterized, G. cheloniae CAWD232 and G. honu CAWD242. Previous chemical and toxicological investigations of these species demonstrated that they did not produce the routinely monitored Pacific ciguatoxins nor maitotoxin-1 (MTX-1), yet were highly toxic to mice via intraperitoneal (i.p.) injection. Bioassay-guided fractionation of methanolic extracts, incorporating wet chemistry and chromatographic techniques, was used to isolate two new MTX analogs; MTX-6 from G. cheloniae CAWD232 and MTX-7 from G. honu CAWD242. Structural characterization of the new MTX analogs used a combination of analytical chemistry techniques, including LC–MS, LC–MS/MS, HR–MS, oxidative cleavage and reduction, and NMR spectroscopy. A substantial portion of the MTX-7 structure was elucidated, and (to a lesser extent) that of MTX-6. Key differences from MTX-1 included monosulfation, additional hydroxyl groups, an extra double bond, and in the case of MTX-7, an additional methyl group. To date, this is the most extensive structural characterization performed on an MTX analog since the complete structure of MTX-1 was published in 1993. MTX-7 was extremely toxic to mice via i.p. injection (LD₅₀ of 0.235 µg/kg), although no toxicity was observed at the highest dose rate via oral administration (155.8 µg/kg). Future research is required to investigate the bioaccumulation and likely biotransformation of the MTX analogs in the marine food web. Full article

(This article belongs to the Section Marine Toxins)

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14 pages, 1519 KiB

Open AccessReview

Dual Role of Chitin as the Double Edged Sword in Controlling the NLRP3 Inflammasome Driven Gastrointestinal and Gynaecological Tumours

by Chetan Roger Dhanjal, Rathnamegha Lingamsetty, Anooshka Pareddy, Se-Kwon Kim and Ritu Raval

Mar. Drugs 2022, 20(7), 452; https://doi.org/10.3390/md20070452 - 11 Jul 2022

Cited by 4 | Viewed by 3490

Abstract

The role of NLRP3 in the tumour microenvironment is elusive. In some cancers, the activation of NLRP3 causes a worse prognosis and in some cancers, NLRP3 increases chances of survivability. However, in many cases where NLRP3 has a protumorigenic role, inhibition of NLRP3 [...] Read more.

The role of NLRP3 in the tumour microenvironment is elusive. In some cancers, the activation of NLRP3 causes a worse prognosis and in some cancers, NLRP3 increases chances of survivability. However, in many cases where NLRP3 has a protumorigenic role, inhibition of NLRP3 would be a crucial step in therapy. Consequently, activation of NLRP3 would be of essence when inflammation is required. Although many ways of inhibiting and activating NLRP3 in cancers have been discussed before, not a lot of focus has been given to chitin and chitosan in this context. The availability of these marine compounds and their versatility in dealing with inflammation needs to be investigated further in relation with cancers, along with other natural extracts. In this review, the effects of NLRP3 on gastrointestinal and gynaecological cancers and the impact of different natural extracts on NLRP3s with special emphasis on chitin and chitosan is discussed. A research gap in using chitin derivatives as anti/pro-inflammatory agents in cancer treatment has been highlighted. Full article

(This article belongs to the Special Issue Marine Carbohydrate-Based Compounds with Medicinal Properties II)

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13 pages, 1229 KiB

Open AccessArticle

Asperopiperazines A and B: Antimicrobial and Cytotoxic Dipeptides from a Tunicate-Derived Fungus Aspergillus sp. DY001

by Diaa T. A. Youssef, Lamiaa A. Shaala and Grégory Genta-Jouve

Mar. Drugs 2022, 20(7), 451; https://doi.org/10.3390/md20070451 - 10 Jul 2022

Cited by 8 | Viewed by 2748

Abstract

Investigation of the cytotoxic fractions of the ethyl acetate extract of the fermentation broth of the tunicate-derived Aspergillus sp. DY001 afforded two new dipeptides, asperopiperazines A and B (1 and 2), along with the previously reported compounds (+)-citreoisocoumarin (3) [...] Read more.

Investigation of the cytotoxic fractions of the ethyl acetate extract of the fermentation broth of the tunicate-derived Aspergillus sp. DY001 afforded two new dipeptides, asperopiperazines A and B (1 and 2), along with the previously reported compounds (+)-citreoisocoumarin (3) and (−)-6,8-di-O-methylcitreoisocoumarin (4). Analyses of the 1D and 2D NMR spectroscopic data of the compounds supported their structural assignments. Asperopiperazine A (1) is a cyclic dipeptide of leucine and phenylalanine moieties, which are substituted with an N-methyl and an N-acetyl group, respectively. On the other hand, asperopiperazine B (2) is a cyclic dipeptide of proline and phenylalanine moieties with a hydroxyl group at C-2 of the proline part. The absolute configuration of the amino acid moieties in 1 and 2 were determined by Marfey’s analyses and DFT NMR chemical shift calculations, leading to their assignment as cyclo(l-NMe-Leu-l-NAc-Phe) and cyclo(d-6-OH-Pro-l-Phe), respectively. Asperopiperazines A and B displayed higher antimicrobial effects against Escherichia coli and Staphylococcus aureus than Candida albicans. Furthermore, compounds 1–4 displayed variable growth inhibitory effects towards HCT 116 and MDA-MB-231 cells, with asperopiperazine A as the most active one towards HCT 116. Full article

(This article belongs to the Special Issue Antimicrobial and Antiviral Agents from Marine Sources)

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21 pages, 1336 KiB

Open AccessReview

Phycobiliproteins—A Family of Algae-Derived Biliproteins: Productions, Characterization and Pharmaceutical Potentials

by Huaxin Chen, Hongtao Qi and Peng Xiong

Mar. Drugs 2022, 20(7), 450; https://doi.org/10.3390/md20070450 - 9 Jul 2022

Cited by 35 | Viewed by 4620

Abstract

Phycobiliproteins (PBPs) are colored and water-soluble biliproteins found in cyanobacteria, rhodophytes, cryptomonads and cyanelles. They are divided into three main types: allophycocyanin, phycocyanin and phycoerythrin, according to their spectral properties. There are two methods for PBPs preparation. One is the extraction and purification [...] Read more.

Phycobiliproteins (PBPs) are colored and water-soluble biliproteins found in cyanobacteria, rhodophytes, cryptomonads and cyanelles. They are divided into three main types: allophycocyanin, phycocyanin and phycoerythrin, according to their spectral properties. There are two methods for PBPs preparation. One is the extraction and purification of native PBPs from Cyanobacteria, Cryptophyta and Rhodophyta, and the other way is the production of recombinant PBPs by heterologous hosts. Apart from their function as light-harvesting antenna in photosynthesis, PBPs can be used as food colorants, nutraceuticals and fluorescent probes in immunofluorescence analysis. An increasing number of reports have revealed their pharmaceutical potentials such as antioxidant, anti-tumor, anti-inflammatory and antidiabetic effects. The advances in PBP biogenesis make it feasible to construct novel PBPs with various activities and produce recombinant PBPs by heterologous hosts at low cost. In this review, we present a critical overview on the productions, characterization and pharmaceutical potentials of PBPs, and discuss the key issues and future perspectives on the exploration of these valuable proteins. Full article

(This article belongs to the Special Issue Pharmacological Activity of Marine Algae Compounds)

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12 pages, 2076 KiB

Open AccessArticle

Two New Phenylhydrazone Derivatives from the Pearl River Estuary Sediment-Derived Streptomyces sp. SCSIO 40020

by Wei Liu, Liang Ma, Liping Zhang, Yuchan Chen, Qingbo Zhang, Haibo Zhang, Weimin Zhang, Changsheng Zhang and Wenjun Zhang

Mar. Drugs 2022, 20(7), 449; https://doi.org/10.3390/md20070449 - 9 Jul 2022

Cited by 7 | Viewed by 2433

Abstract

Two new phenylhydrazone derivatives and one new alkaloid, penzonemycins A–B (1–2) and demethylmycemycin A (3), together with three known compounds including an alkaloid (4) and two sesquiterpenoids (5–6), were isolated from [...] Read more.

Two new phenylhydrazone derivatives and one new alkaloid, penzonemycins A–B (1–2) and demethylmycemycin A (3), together with three known compounds including an alkaloid (4) and two sesquiterpenoids (5–6), were isolated from the Streptomyces sp. SCSIO 40020 obtained from the Pearl River Estuary sediment. Their structures and absolute configurations were assigned by 1D/2D NMR, mass spectroscopy and X-ray crystallography. Compound 1 was evaluated in four human cancer cell lines by the SRB method and displayed weak cytotoxicity in three cancer cell lines, with IC₅₀ values that ranged from 30.44 to 61.92 µM, which were comparable to those of the positive control cisplatin. Bioinformatic analysis of the putative biosynthetic gene cluster indicated a Japp–Klingemann coupling reaction involved in the hydrazone formation of 1 and 2. Full article

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11 pages, 1754 KiB

Open AccessArticle

Exophilone, a Tetrahydrocarbazol-1-one Analogue with Anti-Pulmonary Fibrosis Activity from the Deep-Sea Fungus Exophiala oligosperma MCCC 3A01264

by Ming-Jun Hong, Meng-Jiao Hao, Guang-Yu Zhang, Hou-Jin Li, Zong-Ze Shao, Xiu-Pian Liu, Wen-Zhe Ma, Jun Xu, Taifo Mahmud and Wen-Jian Lan

Mar. Drugs 2022, 20(7), 448; https://doi.org/10.3390/md20070448 - 9 Jul 2022

Cited by 3 | Viewed by 2495

Abstract

A new compound, exophilone (1), together with nine known compounds (2–10), were isolated from a deep-sea-derived fungus, Exophiala oligosperma. Their chemical structures, including the absolute configuration of 1, were elucidated using nuclear magnetic resonance (NMR) spectroscopy, [...] Read more.

A new compound, exophilone (1), together with nine known compounds (2–10), were isolated from a deep-sea-derived fungus, Exophiala oligosperma. Their chemical structures, including the absolute configuration of 1, were elucidated using nuclear magnetic resonance (NMR) spectroscopy, high-resolution electrospray ionization mass spectroscopy (HRESIMS), and electronic circular dichroism (ECD) calculation. Compounds were preliminarily screened for their ability to inhibit collagen accumulation. Compounds 1, 4, and 7 showed weaker inhibition of TGF-β1-induced total collagen accumulation in compared with pirfenidone (73.14% inhibition rate). However, pirfenidone exhibited cytotoxicity (77.57% survival rate), while compounds 1, 4, and 7 showed low cytotoxicity against the HFL1 cell line. Particularly, exophilone (1) showed moderate collagen deposition inhibition effect (60.44% inhibition rate) and low toxicity in HFL1 cells (98.14% survival rate) at a concentration of 10 μM. A molecular docking study suggests that exophilone (1) binds to both TGF-β1 and its receptor through hydrogen bonding interactions. Thus, exophilone (1) was identified as a promising anti-pulmonary fibrosis agent. It has the potential to be developed as a drug candidate for pulmonary fibrosis. Full article

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

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20 pages, 3981 KiB

Open AccessArticle

Immunomodulatory Activity In Vitro and In Vivo of a Sulfated Polysaccharide with Novel Structure from the Green Alga Ulvaconglobata Kjellman

by Sujian Cao, Yajing Yang, Shan Liu, Zhuling Shao, Xiao Chu and Wenjun Mao

Mar. Drugs 2022, 20(7), 447; https://doi.org/10.3390/md20070447 - 8 Jul 2022

Cited by 12 | Viewed by 2962

Abstract

Algae accumulate large amounts of polysaccharides in their cell walls or intercellular regions. Polysaccharides from algae possess high potential as promising candidates for marine drug development. In this study, a sulfated polysaccharide, UCP, from the green alga Ulva conglobata Kjellman was obtained by [...] Read more.

Algae accumulate large amounts of polysaccharides in their cell walls or intercellular regions. Polysaccharides from algae possess high potential as promising candidates for marine drug development. In this study, a sulfated polysaccharide, UCP, from the green alga Ulva conglobata Kjellman was obtained by water extraction, anion-exchange, and size-exclusion chromatography purification, and its structure was characterized by a combination of chemical and spectroscopic methods. UCP mainly consisted of →4)-α/β-l-Rhap-(1→, →4)-β-d-Xylp-(1→ and →4)-β-d-GlcAp-(1→ residues. Sulfate ester groups were substituted mainly at C-3 of →4)-l-Rhap-(1→ and C-2 of →4)-β-d-Xylp-(1→. Partial glycosylation was at C-2 of →4)-α-l-Rhap-(1→ residues. UCP possessed a potent immunomodulatory effect in vitro, evaluated by the assays of lymphocyte proliferation and macrophage phagocytosis. The immunomodulatory activity of UCP in vivo was further investigated using immunosuppressive mice induced by cyclophosphamide. The results showed that UCP markedly increased the spleen and thymus indexes and ameliorated the cyclophosphamide-induced damage to the spleen and thymus. UCP could increase the levels of white blood cells, lymphocytes, and platelets, and improve the hematopoietic inhibition caused by cyclophosphamide. Moreover, UCP significantly promoted the secretions of the immunoglobulin (Ig)G, IgE, and IgM. The data demonstrated that UCP is a novel sulfated polysaccharide and may be a promising immunomodulatory agent. Full article

(This article belongs to the Collection Marine Polysaccharides)

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7 pages, 1028 KiB

Open AccessCommunication

Monocaprin Enhances Bioavailability of Fucoxanthin in Diabetic/Obese KK-A^y Mice

by Kodai Nagata, Naoki Takatani, Fumiaki Beppu, Aya Abe, Etsuko Tominaga, Tomohisa Fukuhara, Makoto Ozeki and Masashi Hosokawa

Mar. Drugs 2022, 20(7), 446; https://doi.org/10.3390/md20070446 - 7 Jul 2022

Cited by 4 | Viewed by 2047

Abstract

Fucoxanthin is a marine carotenoid found in brown seaweeds and several microalgae. It has been reported that fucoxanthin has health benefits such as anti-obesity and anti-diabetic effects. To facilitate fucoxanthin applications in the food industry, it is important to improve its low bioavailability. [...] Read more.

Fucoxanthin is a marine carotenoid found in brown seaweeds and several microalgae. It has been reported that fucoxanthin has health benefits such as anti-obesity and anti-diabetic effects. To facilitate fucoxanthin applications in the food industry, it is important to improve its low bioavailability. We attempted the combined feeding of fucoxanthin-containing seaweed oil (SO) and monocaprin in a powder diet and analyzed the fucoxanthin metabolite contents in the liver, small intestine and serum of diabetic/obese KK-A^y mice. After 4 weeks of feeding with the experimental diets, the serum fucoxanthinol concentrations of the mice fed 0.2% SO and 0.5% monocaprin were higher than those of the 0.2% SO-fed mice. Furthermore, fucoxanthinol accumulation in the liver and small intestine tended to increase in a combination diet of 0.2% SO and 0.125–0.5% monocaprin compared with a diet of 0.2% SO alone, although amarouciaxanthin A accumulation was not different among the 0.2% SO-fed groups. These results suggest that a combination of monocaprin with fucoxanthin-containing SO is an effective treatment for improving the bioavailability of fucoxanthin. Full article

(This article belongs to the Special Issue Fucoxanthin and Astaxanthin—Production, Biofunction, and Application)

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44 pages, 3057 KiB

Open AccessReview

Seaweed Phenolics as Natural Antioxidants, Aquafeed Additives, Veterinary Treatments and Cross-Linkers for Microencapsulation

by Tharuka Gunathilake, Taiwo O. Akanbi, Hafiz A. R. Suleria, Tim D. Nalder, David S. Francis and Colin J. Barrow

Mar. Drugs 2022, 20(7), 445; https://doi.org/10.3390/md20070445 - 7 Jul 2022

Cited by 37 | Viewed by 6573

Abstract

Driven by consumer demand and government policies, synthetic additives in aquafeed require substitution with sustainable and natural alternatives. Seaweeds have been shown to be a sustainable marine source of novel bioactive phenolic compounds that can be used in food, animal and aqua feeds, [...] Read more.

Driven by consumer demand and government policies, synthetic additives in aquafeed require substitution with sustainable and natural alternatives. Seaweeds have been shown to be a sustainable marine source of novel bioactive phenolic compounds that can be used in food, animal and aqua feeds, or microencapsulation applications. For example, phlorotannins are a structurally unique polymeric phenolic group exclusively found in brown seaweed that act through multiple antioxidant mechanisms. Seaweed phenolics show high affinities for binding proteins via covalent and non-covalent bonds and can have specific bioactivities due to their structures and associated physicochemical properties. Their ability to act as protein cross-linkers means they can be used to enhance the rheological and mechanical properties of food-grade delivery systems, such as microencapsulation, which is a new area of investigation illustrating the versatility of seaweed phenolics. Here we review how seaweed phenolics can be used in a range of applications, with reference to their bioactivity and structural properties. Full article

(This article belongs to the Section Marine-Derived Ingredients for Drugs, Cosmeceuticals and Nutraceuticals)

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18 pages, 30010 KiB

Open AccessArticle

The Ameliorative Effect of COST on Diet-Induced Lipid Metabolism Disorders by Regulating Intestinal Microbiota

by Huimin You, Xiaoyi Deng, Yan Bai, Jincan He, Hua Cao, Qishi Che, Jiao Guo and Zhengquan Su

Mar. Drugs 2022, 20(7), 444; https://doi.org/10.3390/md20070444 - 7 Jul 2022

Cited by 7 | Viewed by 2202

Abstract

Background: Chitosan oligosaccharides, with an average molecular weight ≤ 1000 Da (COST), is a natural marine product that has the potential to improve intestinal microflora and resist lipid metabolism disorders. Methods: First, by establishing a mice model of lipid metabolism disorder induced by [...] Read more.

Background: Chitosan oligosaccharides, with an average molecular weight ≤ 1000 Da (COST), is a natural marine product that has the potential to improve intestinal microflora and resist lipid metabolism disorders. Methods: First, by establishing a mice model of lipid metabolism disorder induced by a high fat and high sugar diet, it is proven that COST can reduce lipid metabolism disorder, which may play a role in regulating intestinal microorganisms. Then, the key role of COST in the treatment of intestinal microorganisms is further confirmed through the method of COST-treated feces and fecal bacteria transplantation. Conclusions: intestinal microbiota plays a key role in COST inhibition of lipid metabolism disorder induced by a high fat and high sugar diet. In particular, COST may play a central regulatory role in microbiota, including Bacteroides, Akkermansia, and Desulfovibrio. Taken together, our work suggests that COST may improve the composition of gut microbes, increase the abundance of beneficial bacteria, improve lipid metabolism disorders, and inhibit the development of metabolic disorders. Full article

(This article belongs to the Special Issue Marine Natural Products, Gut Microbiota and Health Benefits)

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12 pages, 1831 KiB

Open AccessArticle

Rare Carbon-Bridged Citrinin Dimers from the Starfish-Derived Symbiotic Fungus Penicillium sp. GGF16-1-2

by Hao Fan, Zhi-Mian Shi, Yan-Hu Lei, Mei-Xia Si-Tu, Feng-Guo Zhou, Chan Feng, Xia Wei, Xue-Hua Shao, Yang Chen and Cui-Xian Zhang

Mar. Drugs 2022, 20(7), 443; https://doi.org/10.3390/md20070443 - 6 Jul 2022

Cited by 18 | Viewed by 2611

Abstract

Four novel, rare carbon-bridged citrinin dimers, namely dicitrinones G–J (1–4), and five known analogs (5–9) were isolated from the starfish-derived fungus Penicillium sp. GGF 16-1-2. Their structures were elucidated by extensive spectroscopic analysis and quantum [...] Read more.

Four novel, rare carbon-bridged citrinin dimers, namely dicitrinones G–J (1–4), and five known analogs (5–9) were isolated from the starfish-derived fungus Penicillium sp. GGF 16-1-2. Their structures were elucidated by extensive spectroscopic analysis and quantum chemical calculations. Compounds 1–9 exhibited strong antifungal activities against Colletotrichum gloeosporioides with LD₅₀ values from 0.61 μg/mL to 16.14 μg/mL. Meanwhile, all compounds were evaluated for their cytotoxic activities against human pancreatic cancer BXPC-3 and PANC-1 cell lines; as a result, compound 1 showed more significant cytotoxicities than the positive control against both cell lines. In addition, based on the analyses of the protein-protein interaction (PPI) network and Western blot, 1 could induce apoptosis by activating caspase 3 proteins (CASP3). Full article

(This article belongs to the Special Issue Bioactive Compounds from the Deep-Sea-Derived Microorganisms)

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16 pages, 3105 KiB

Open AccessArticle

Identification, Characteristics and Function of Phosphoglucomutase (PGM) in the Agar Biosynthesis and Carbon Flux in the Agarophyte Gracilariopsis lemaneiformis (Rhodophyta)

by Qionglin Chen, Xinlei Yu, Shixia Liu, Suya Luo, Xiaojiao Chen, Nianjun Xu and Xue Sun

Mar. Drugs 2022, 20(7), 442; https://doi.org/10.3390/md20070442 - 2 Jul 2022

Cited by 7 | Viewed by 2968

Abstract

Agar is widely applied across the food, pharmaceutical and biotechnology industries, owing to its various bioactive functions. To better understand the agar biosynthesis in commercial seaweed Gracilariopsis lemaneiformis, the activities of four enzymes participating in the agar biosynthesis were detected, and phosphoglucomutase [...] Read more.

Agar is widely applied across the food, pharmaceutical and biotechnology industries, owing to its various bioactive functions. To better understand the agar biosynthesis in commercial seaweed Gracilariopsis lemaneiformis, the activities of four enzymes participating in the agar biosynthesis were detected, and phosphoglucomutase (PGM) was confirmed as highly correlated with agar accumulation. Three genes of PGM (GlPGM1, GlPGM2 and GlPGM3) were identified from the G. lemaneiformis genome. The subcellular localization analysis validated that GlPGM1 was located in the chloroplast and GlPGM3 was not significantly distributed in the organelles. Both the GlPGM1 and GlPGM3 protein levels showed a remarkable consistency with the agar variations, and GlPGM3 may participate in the carbon flux between (iso)floridoside, floridean starch and agar synthesis. After treatment with the PGM inhibitor, the agar and floridean starch contents and the activities of floridean starch synthase were significantly decreased; products identified in the Calvin cycle, the pentose phosphate pathway, the Embden-Meyerhof-Parnas pathway and the tricarboxylic acid cycle were depressed; however, lipids, phenolic acids and the intermediate metabolites, fructose-1,6-phosphate were upregulated. These findings reveal the essential role of PGM in regulating the carbon flux between agar and other carbohydrates in G. lemaneiformis, providing a guide for the artificial regulation of agar accumulation. Full article

(This article belongs to the Special Issue Carbohydrate-Containing Marine Compounds of Mixed Biogenesis II)

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13 pages, 744 KiB

Open AccessArticle

Antioxidant Efficacy of a Spirulina Liquid Extract on Oxidative Stress Status and Metabolic Disturbances in Subjects with Metabolic Syndrome

by N’Deye Lallah Nina Koite, N’gouro Issa Sanogo, Olivier Lépine, Jean-Marie Bard and Khadija Ouguerram

Mar. Drugs 2022, 20(7), 441; https://doi.org/10.3390/md20070441 - 1 Jul 2022

Cited by 8 | Viewed by 4691

Abstract

Lipid peroxidation is associated with the development of some pathologies, such as cardiovascular diseases. Reduction in oxidative stress by antioxidants, such as Arthrospira (formely Spirulina), helps improving this redox imbalance. The aim of the study was to evaluate the effect of the [...] Read more.

Lipid peroxidation is associated with the development of some pathologies, such as cardiovascular diseases. Reduction in oxidative stress by antioxidants, such as Arthrospira (formely Spirulina), helps improving this redox imbalance. The aim of the study was to evaluate the effect of the Arthrospira liquid extract “Spirulysat^®” on oxidative markers—in particular, oxidized LDL (oxLDL)/total LDL cholesterol—and isoprostanes and to investigate its impact on lipid and glucose metabolism in the metabolic syndrome subject. A controlled, randomised, double-blind design was conducted in 40 subjects aged 18 to 65 years with metabolic syndrome after a daily intake of Spirulysat^® or placebo for twelve weeks. Blood and urinary samples were collected at three visits (V1, V2, V3) in the two groups for parameters determination. Although the Spirulysat^® group showed a decrease at all visits of the oxLDL/total cholesterol ratio, there was no significant difference compared to the placebo (p = 0.36). The urinary isoprostanes concentration in the Spirulysat^® group was reduced (p = 0.014) at V3. Plasma triglycerides decreased at V3 (p = 0.003) and HDL-cholesterol increased (p = 0.031) at all visits with Spirulysat^®. In conclusion, Spirulysat^® did not change the oxidized LDL (oxLDL)/LDL ratio but decreased the urinary isoprostanes, plasma triglycerides and increased HDL cholesterol, suggesting a beneficial effect on metabolic syndrome. Full article

(This article belongs to the Special Issue Microalgal Bioactive Molecules and Their Implication in Health and Disease)

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25 pages, 2699 KiB

Open AccessReview

Random Mutagenesis as a Promising Tool for Microalgal Strain Improvement towards Industrial Production

by Mafalda Trovão, Lisa M. Schüler, Adriana Machado, Gabriel Bombo, Sofia Navalho, Ana Barros, Hugo Pereira, Joana Silva, Filomena Freitas and João Varela

Mar. Drugs 2022, 20(7), 440; https://doi.org/10.3390/md20070440 - 30 Jun 2022

Cited by 53 | Viewed by 8129

Abstract

Microalgae have become a promising novel and sustainable feedstock for meeting the rising demand for food and feed. However, microalgae-based products are currently hindered by high production costs. One major reason for this is that commonly cultivated wildtype strains do not possess the [...] Read more.

Microalgae have become a promising novel and sustainable feedstock for meeting the rising demand for food and feed. However, microalgae-based products are currently hindered by high production costs. One major reason for this is that commonly cultivated wildtype strains do not possess the robustness and productivity required for successful industrial production. Several strain improvement technologies have been developed towards creating more stress tolerant and productive strains. While classical methods of forward genetics have been extensively used to determine gene function of randomly generated mutants, reverse genetics has been explored to generate specific mutations and target phenotypes. Site-directed mutagenesis can be accomplished by employing different gene editing tools, which enable the generation of tailor-made genotypes. Nevertheless, strategies promoting the selection of randomly generated mutants avoid the introduction of foreign genetic material. In this paper, we review different microalgal strain improvement approaches and their applications, with a primary focus on random mutagenesis. Current challenges hampering strain improvement, selection, and commercialization will be discussed. The combination of these approaches with high-throughput technologies, such as fluorescence-activated cell sorting, as tools to select the most promising mutants, will also be discussed. Full article

(This article belongs to the Topic Microalgal Biotechnology for Bioproducts and Food Applications, 2nd Volume)

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21 pages, 8014 KiB

Open AccessArticle

Porphyra tenera Protects against PM_2.5-Induced Cognitive Dysfunction with the Regulation of Gut Function

by Seon Kyeong Park, Jin Yong Kang, Jong Min Kim, Min Ji Kim, Hyo Lim Lee, Jong Hyun Moon, Hye Rin Jeong, Hyun-Jin Kim, Min-Yu Chung and Ho Jin Heo

Mar. Drugs 2022, 20(7), 439; https://doi.org/10.3390/md20070439 - 30 Jun 2022

Cited by 3 | Viewed by 2983

Abstract

To evaluate the biological effects of Porphyra tenera (P. tenera), we tried to confirm the possibility that the intake of P. tenera could modulate cognitive and intestinal functions in PM_2.5-induced cognitive decline mice. P. tenera attenuated PM_2.5-induced [...] Read more.

To evaluate the biological effects of Porphyra tenera (P. tenera), we tried to confirm the possibility that the intake of P. tenera could modulate cognitive and intestinal functions in PM_2.5-induced cognitive decline mice. P. tenera attenuated PM_2.5-induced learning and memory impairment through antioxidant and anti-inflammatory effects by regulating the mitochondrial function and TLR-initiated NF-κB signaling. In addition, P. tenera effectively alleviated Aβ production/tau phosphorylation by inhibiting the JNK phosphorylation. Also, the bioactive constituents of P. tenera determined the sulfated galactan, mycosporine-like amino acids (MAAs), and chlorophyll derivatives. Moreover, the bioactive compounds of P. tenera by gut fermentation protected against gut dysbiosis and intestinal tight junction damage with a decrease in inflammatory response and short-chain fatty acid production. Based on these results, our findings suggest that P. tenera with sulfated galactan and MAAs is a potential material for cognitive function improvement. Full article

(This article belongs to the Special Issue Neuroprotective Effects of Marine Natural Products 2022)

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14 pages, 4022 KiB

Open AccessArticle

Synthesis of 6-Halo-Substituted Pericosine A and an Evaluation of Their Antitumor and Antiglycosidase Activities

by Yoshihide Usami, Yoshino Mizobuchi, Mai Ijuin, Takeshi Yamada, Mizuki Morita, Koji Mizuki, Hiroki Yoneyama and Shinya Harusawa

Mar. Drugs 2022, 20(7), 438; https://doi.org/10.3390/md20070438 - 30 Jun 2022

Cited by 1 | Viewed by 2003

Abstract

The enantiomers of 6-fluoro-, 6-bromo-, and 6-iodopericosine A were synthesized. An efficient synthesis of both enantiomers of pericoxide via 6-bromopericosine A was also developed. These 6-halo-substituted pericosine A derivatives were evaluated in terms of their antitumor activity against three types of tumor cells [...] Read more.

The enantiomers of 6-fluoro-, 6-bromo-, and 6-iodopericosine A were synthesized. An efficient synthesis of both enantiomers of pericoxide via 6-bromopericosine A was also developed. These 6-halo-substituted pericosine A derivatives were evaluated in terms of their antitumor activity against three types of tumor cells (p388, L1210, and HL-60) and glycosidase inhibitory activity. The bromo- and iodo-congeners exhibited moderate antitumor activity similar to pericosine A against the three types of tumor cell lines studied. The fluorinated compound was less active than the others, including pericosine A. In the antitumor assay, no significant difference in potency between the enantiomers was observed for any of the halogenated compounds. Meanwhile, the (−)-6-fluoro- and (−)-6-bromo-congeners inhibited α-glucosidase to a greater extent than those of their corresponding (+)-enantiomers, whereas (+)-iodopericosine A showed increased activity when compared to its (−)-enantiomer. Full article

(This article belongs to the Special Issue Chemical Modification and Structural Elucidation of Marine Natural Products)

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20 pages, 8475 KiB

Open AccessArticle

Preparation and Characterization of Tilapia Collagen-Thermoplastic Polyurethane Composite Nanofiber Membranes

by Sijia Wu, Longhe Yang and Junde Chen

Mar. Drugs 2022, 20(7), 437; https://doi.org/10.3390/md20070437 - 30 Jun 2022

Cited by 5 | Viewed by 2343

Abstract

Marine collagen is an ideal material for tissue engineering due to its excellent biological properties. However, the limited mechanical properties and poor stability of marine collagen limit its application in tissue engineering. Here, collagen was extracted from the skin of tilapia (Oreochromis [...] Read more.

Marine collagen is an ideal material for tissue engineering due to its excellent biological properties. However, the limited mechanical properties and poor stability of marine collagen limit its application in tissue engineering. Here, collagen was extracted from the skin of tilapia (Oreochromis nilotica). Collagen-thermoplastic polyurethane (Col-TPU) fibrous membranes were prepared using tilapia collagen as a foundational material, and their physicochemical and biocompatibility were investigated. Fourier transform infrared spectroscopy results showed that thermoplastic polyurethane was successfully combined with collagen, and the triple helix structure of collagen was retained. X-ray diffraction and differential scanning calorimetry results showed relatively good compatibility between collagen and TPU.SEM results showed that the average diameter of the composite nanofiber membrane decreased with increasing thermoplastic polyurethane proportion. The mechanical evaluation and thermogravimetric analysis showed that the thermal stability and tensile properties of Col-TPU fibrous membranes were significantly improved with increasing TPU. Cytotoxicity experiments confirmed that fibrous membranes with different ratios of thermoplastic polyurethane content showed no significant toxicity to fibroblasts; Col-TPU fibrous membranes were conducive to the migration and adhesion of cells. Thus, these Col-TPU composite nanofiber membranes might be used as a potential biomaterial in tissue regeneration. Full article

(This article belongs to the Special Issue Biomedical and Pharmacological Applications of Marine Collagen)

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16 pages, 1964 KiB

Open AccessArticle

S-Assimilation Influences in Carrageenan Biosynthesis Genes during Ethylene-Induced Carposporogenesis in Red Seaweed Grateloupia imbricata

by Diana del Rosario-Santana, Rafael R. Robaina and Pilar Garcia-Jimenez

Mar. Drugs 2022, 20(7), 436; https://doi.org/10.3390/md20070436 - 29 Jun 2022

Cited by 3 | Viewed by 2347

Abstract

The synthesis of cell-wall sulfated galactans proceeds through UDP galactose, a major nucleotide sugar in red seaweed, whilst sulfate is transported through S-transporters into algae. Moreover, synthesis of ethylene, a volatile plant growth regulator that plays an important role in red seaweed reproduction, [...] Read more.

The synthesis of cell-wall sulfated galactans proceeds through UDP galactose, a major nucleotide sugar in red seaweed, whilst sulfate is transported through S-transporters into algae. Moreover, synthesis of ethylene, a volatile plant growth regulator that plays an important role in red seaweed reproduction, occurs through S-adenosyl methionine. This means that sulfur metabolism is involved in reproduction events as well as sulfated galactan synthesis of red seaweed. In this work we study the effects of methionine and MgSO₄ on gene expression of polygalactan synthesis through phosphoglucomutase (PGM) and galactose 1 phosphate uridyltransferase (GALT) and of sulfate assimilation (S-transporter and sulfate adenylyltransferase, SAT) using treatment of ethylene for 15 min, which elicited cystocarp development in Grateloupia imbricata. Also, expressions of carbohydrate sulfotransferase and galactose-6-sulfurylase in charge of the addition and removal of sulfate groups to galactans backbone were examined. Outstanding results occurred in the presence of methionine, which provoked an increment in transcript number of genes encoding S-transporter and assimilation compared to controls regardless of the development stage of thalli. Otherwise, methionine diminished the transcript levels of PGM and GALT and expressions are associated with the fertilization stage of thalli of G. imbricata. As opposite, methionine and MgSO₄ did not affect the transcript number of carbohydrate sulfotransferase and galactose-6-sulfurylase. Nonetheless, differential expression was obtained for sulfurylases according to the development stages of thalli of G. imbricata. Full article

(This article belongs to the Special Issue Marine Drugs Research in Spain)

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