Marine Drugs

25 pages, 14025 KiB

Open AccessFeature PaperEditor’s ChoiceReview

A Soft Spot for Chemistry–Current Taxonomic and Evolutionary Implications of Sponge Secondary Metabolite Distribution

by Adrian Galitz, Yoichi Nakao, Peter J. Schupp, Gert Wörheide and Dirk Erpenbeck

Mar. Drugs 2021, 19(8), 448; https://doi.org/10.3390/md19080448 - 4 Aug 2021

Cited by 20 | Viewed by 5029

Marine sponges are the most prolific marine sources for discovery of novel bioactive compounds. Sponge secondary metabolites are sought-after for their potential in pharmaceutical applications, and in the past, they were also used as taxonomic markers alongside the difficult and homoplasy-prone sponge morphology [...] Read more.

Marine sponges are the most prolific marine sources for discovery of novel bioactive compounds. Sponge secondary metabolites are sought-after for their potential in pharmaceutical applications, and in the past, they were also used as taxonomic markers alongside the difficult and homoplasy-prone sponge morphology for species delineation (chemotaxonomy). The understanding of phylogenetic distribution and distinctiveness of metabolites to sponge lineages is pivotal to reveal pathways and evolution of compound production in sponges. This benefits the discovery rate and yield of bioprospecting for novel marine natural products by identifying lineages with high potential of being new sources of valuable sponge compounds. In this review, we summarize the current biochemical data on sponges and compare the metabolite distribution against a sponge phylogeny. We assess compound specificity to lineages, potential convergences, and suitability as diagnostic phylogenetic markers. Our study finds compound distribution corroborating current (molecular) phylogenetic hypotheses, which include yet unaccepted polyphyly of several demosponge orders and families. Likewise, several compounds and compound groups display a high degree of lineage specificity, which suggests homologous biosynthetic pathways among their taxa, which identifies yet unstudied species of this lineage as promising bioprospecting targets. Full article

(This article belongs to the Special Issue Marine Sponge Biotechnology)

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20 pages, 2067 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Identification of a New Antimicrobial, Desertomycin H, Utilizing a Modified Crowded Plate Technique

by Osama G. Mohamed, Sadaf Dorandish, Rebecca Lindow, Megan Steltz, Ifrah Shoukat, Maira Shoukat, Hussein Chehade, Sara Baghdadi, Madelaine McAlister-Raeburn, Asad Kamal, Dawit Abebe, Khaled Ali, Chelsey Ivy, Maria Antonova, Pamela Schultz, Michael Angell, Daniel Clemans, Timothy Friebe, David Sherman, Anne M. Casper, Paul A. Price and Ashootosh Tripathi Show full author list Hide full author list

Mar. Drugs 2021, 19(8), 424; https://doi.org/10.3390/md19080424 - 27 Jul 2021

Cited by 6 | Viewed by 11813

Abstract

The antibiotic-resistant bacteria-associated infections are a major global healthcare threat. New classes of antimicrobial compounds are urgently needed as the frequency of infections caused by multidrug-resistant microbes continues to rise. Recent metagenomic data have demonstrated that there is still biosynthetic potential encoded in [...] Read more.

The antibiotic-resistant bacteria-associated infections are a major global healthcare threat. New classes of antimicrobial compounds are urgently needed as the frequency of infections caused by multidrug-resistant microbes continues to rise. Recent metagenomic data have demonstrated that there is still biosynthetic potential encoded in but transcriptionally silent in cultivatable bacterial genomes. However, the culture conditions required to identify and express silent biosynthetic gene clusters that yield natural products with antimicrobial activity are largely unknown. Here, we describe a new antibiotic discovery scheme, dubbed the modified crowded plate technique (mCPT), that utilizes complex microbial interactions to elicit antimicrobial production from otherwise silent biosynthetic gene clusters. Using the mCPT as part of the antibiotic crowdsourcing educational program Tiny Earth^TM, we isolated over 1400 antibiotic-producing microbes, including 62 showing activity against multidrug-resistant pathogens. The natural product extracts generated from six microbial isolates showed potent activity against vancomycin-intermediate resistant Staphylococcus aureus. We utilized a targeted approach that coupled mass spectrometry data with bioactivity, yielding a new macrolactone class of metabolite, desertomycin H. In this study, we successfully demonstrate a concept that significantly increased our ability to quickly and efficiently identify microbes capable of the silent antibiotic production. Full article

(This article belongs to the Special Issue Emerging Technologies and Inter-disciplinary Approaches to Explore the Therapeutic Potential of Marine Biodiversity)

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12 pages, 1968 KiB

Open AccessEditor’s ChoiceArticle

Monitoring the Emergence of Algal Toxins in Shellfish: First Report on Detection of Brevetoxins in French Mediterranean Mussels

by Zouher Amzil, Amélie Derrien, Aouregan Terre Terrillon, Audrey Duval, Coralie Connes, Françoise Marco-Miralles, Elisabeth Nézan and Kenneth Neil Mertens

Mar. Drugs 2021, 19(7), 393; https://doi.org/10.3390/md19070393 - 14 Jul 2021

Cited by 19 | Viewed by 3817

Abstract

In France, four groups of lipophilic toxins are currently regulated: okadaic acid/dinophysistoxins, pectenotoxins, yessotoxins and azaspiracids. However, many other families of toxins exist, which can be emerging toxins. Emerging toxins include both toxins recently detected in a specific area of France but not [...] Read more.

In France, four groups of lipophilic toxins are currently regulated: okadaic acid/dinophysistoxins, pectenotoxins, yessotoxins and azaspiracids. However, many other families of toxins exist, which can be emerging toxins. Emerging toxins include both toxins recently detected in a specific area of France but not regulated yet (e.g., cyclic imines, ovatoxins) or toxins only detected outside of France (e.g., brevetoxins). To anticipate the introduction to France of these emerging toxins, a monitoring program called EMERGTOX was set up along the French coasts in 2018. The single-laboratory validation of this approach was performed according to the NF V03-110 guidelines by building an accuracy profile. Our specific, reliable and sensitive approach allowed us to detect brevetoxins (BTX-2 and/or BTX-3) in addition to the lipophilic toxins already regulated in France. Brevetoxins were detected for the first time in French Mediterranean mussels (Diana Lagoon, Corsica) in autumn 2018, and regularly every year since during the same seasons (autumn, winter). The maximum content found was 345 µg (BTX-2 + BTX-3)/kg in mussel digestive glands in November 2020. None were detected in oysters sampled at the same site. In addition, a retroactive analysis of preserved mussels demonstrated the presence of BTX-3 in mussels from the same site sampled in November 2015. The detection of BTX could be related to the presence in situ at the same period of four Karenia species and two raphidophytes, which all could be potential producers of these toxins. Further investigations are necessary to understand the origin of these toxins. Full article

(This article belongs to the Special Issue Novel Methods for Marine Toxins Detection and Quantification)

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19 pages, 2525 KiB

Open AccessEditor’s ChoiceReview

From Sea to Skin: Is There a Future for Natural Photoprotectants?

by Alfonsina Milito, Immacolata Castellano and Elisabetta Damiani

Mar. Drugs 2021, 19(7), 379; https://doi.org/10.3390/md19070379 - 30 Jun 2021

Cited by 24 | Viewed by 6055

Abstract

In the last few decades, the thinning of the ozone layer due to increased atmospheric pollution has exacerbated the negative effects of excessive exposure to solar ultraviolet radiation (UVR), and skin cancer has become a major public health concern. In order to prevent [...] Read more.

In the last few decades, the thinning of the ozone layer due to increased atmospheric pollution has exacerbated the negative effects of excessive exposure to solar ultraviolet radiation (UVR), and skin cancer has become a major public health concern. In order to prevent skin damage, public health advice mainly focuses on the use of sunscreens, along with wearing protective clothing and avoiding sun exposure during peak hours. Sunscreens present on the market are topical formulations that contain a number of different synthetic, organic, and inorganic UVR filters with different absorbance profiles, which, when combined, provide broad UVR spectrum protection. However, increased evidence suggests that some of these compounds cause subtle damage to marine ecosystems. One alternative may be the use of natural products that are produced in a wide range of marine species and are mainly thought to act as a defense against UVR-mediated damage. However, their potential for human photoprotection is largely under-investigated. In this review, attention has been placed on the molecular strategies adopted by marine organisms to counteract UVR-induced negative effects and we provide a broad portrayal of the recent literature concerning marine-derived natural products having potential as natural sunscreens/photoprotectants for human skin. Their chemical structure, UVR absorption properties, and their pleiotropic role as bioactive molecules are discussed. Most studies strongly suggest that these natural products could be promising for use in biocompatible sunscreens and may represent an alternative eco-friendly approach to protect humans against UV-induced skin damage. Full article

(This article belongs to the Special Issue Antiphotoaging and Photoprotective Compounds from Marine Organisms)

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26 pages, 4016 KiB

Open AccessEditor’s ChoiceArticle

Untargeted Metabolomics Approach for the Discovery of Environment-Related Pyran-2-Ones Chemodiversity in a Marine-Sourced Penicillium restrictum

by Van-Tuyen Le, Samuel Bertrand, Thibaut Robiou du Pont, Fabrice Fleury, Nathalie Caroff, Sandra Bourgeade-Delmas, Emmanuel Gentil, Cedric Logé, Gregory Genta-Jouve and Olivier Grovel

Mar. Drugs 2021, 19(7), 378; https://doi.org/10.3390/md19070378 - 29 Jun 2021

Cited by 9 | Viewed by 4447

Abstract

Very little is known about chemical interactions between fungi and their mollusc host within marine environments. Here, we investigated the metabolome of a Penicillium restrictum MMS417 strain isolated from the blue mussel Mytilus edulis collected on the Loire estuary, France. Following the OSMAC [...] Read more.

Very little is known about chemical interactions between fungi and their mollusc host within marine environments. Here, we investigated the metabolome of a Penicillium restrictum MMS417 strain isolated from the blue mussel Mytilus edulis collected on the Loire estuary, France. Following the OSMAC approach with the use of 14 culture media, the effect of salinity and of a mussel-derived medium on the metabolic expression were analysed using HPLC-UV/DAD-HRMS/MS. An untargeted metabolomics study was performed using principal component analysis (PCA), orthogonal projection to latent structure discriminant analysis (O-PLSDA) and molecular networking (MN). It highlighted some compounds belonging to sterols, macrolides and pyran-2-ones, which were specifically induced in marine conditions. In particular, a high chemical diversity of pyran-2-ones was found to be related to the presence of mussel extract in the culture medium. Mass spectrometry (MS)- and UV-guided purification resulted in the isolation of five new natural fungal pyran-2-one derivatives—5,6-dihydro-6S-hydroxymethyl-4-methoxy-2H-pyran-2-one (1), (6S, 1’R, 2’S)-LL-P880β (3), 5,6-dihydro-4-methoxy-6S-(1’S, 2’S-dihydroxy pent-3’(E)-enyl)-2H-pyran-2-one (4), 4-methoxy-6-(1’R, 2’S-dihydroxy pent-3’(E)-enyl)-2H-pyran-2-one (6) and 4-methoxy-2H-pyran-2-one (7)—together with the known (6S, 1’S, 2’S)-LL-P880β (2), (1’R, 2’S)-LL-P880γ (5), 5,6-dihydro-4-methoxy-2H-pyran-2-one (8), (6S, 1’S, 2’R)-LL-P880β (9), (6S, 1’S)-pestalotin (10), 1’R-dehydropestalotin (11) and 6-pentyl-4-methoxy-2H-pyran-2-one (12) from the mussel-derived culture medium extract. The structures of 1-12 were determined by 1D- and 2D-MMR experiments as well as high-resolution tandem MS, ECD and DP4 calculations. Some of these compounds were evaluated for their cytotoxic, antibacterial, antileishmanial and in-silico PTP1B inhibitory activities. These results illustrate the utility in using host-derived media for the discovery of new natural products. Full article

(This article belongs to the Special Issue 3rd International Conference of the Marine Fungal Natural Products (MaFNaP))

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10 pages, 983 KiB

Open AccessEditor’s ChoiceArticle

Agelasine Diterpenoids and Cbl-b Inhibitory Ageliferins from the Coralline Demosponge Astrosclera willeyana

by Wei Jiang, Dongdong Wang, Brice A. P. Wilson, Unwoo Kang, Heidi R. Bokesch, Emily A. Smith, Antony Wamiru, Ekaterina I. Goncharova, Donna Voeller, Stanley Lipkowitz, Barry R. O’Keefe and Kirk R. Gustafson

Mar. Drugs 2021, 19(7), 361; https://doi.org/10.3390/md19070361 - 24 Jun 2021

Cited by 8 | Viewed by 3098

Abstract

An extract of the coralline demosponge Astrosclera willeyana inhibited the ubiquitin ligase activity of the immunomodulatory protein Cbl-b. The bioassay-guided separation of the extract provided ten active compounds, including three new N-methyladenine-containing diterpenoids, agelasines W–Y (1–3), a new [...] Read more.

An extract of the coralline demosponge Astrosclera willeyana inhibited the ubiquitin ligase activity of the immunomodulatory protein Cbl-b. The bioassay-guided separation of the extract provided ten active compounds, including three new N-methyladenine-containing diterpenoids, agelasines W–Y (1–3), a new bromopyrrole alkaloid, N(1)-methylisoageliferin (4), and six known ageliferin derivatives (5–10). The structures of the new compounds were elucidated from their spectroscopic and spectrometric data, including IR, HRESIMS, and NMR, and by comparison with spectroscopic data in the literature. While all of the isolated compounds showed Cbl-b inhibitory activities, ageliferins (4–10) were the most potent metabolites, with IC₅₀ values that ranged from 18 to 35 μM. Full article

(This article belongs to the Special Issue Marine Natural Products: A Themed Issue in Honor of Professor John Blunt and Professor Murray Munro)

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75 pages, 14661 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Antitumor Profile of Carbon-Bridged Steroids (CBS) and Triterpenoids

by Valery M. Dembitsky, Tatyana A. Gloriozova and Vladimir V. Poroikov

Mar. Drugs 2021, 19(6), 324; https://doi.org/10.3390/md19060324 - 3 Jun 2021

Cited by 9 | Viewed by 4996

Abstract

This review focuses on the rare group of carbon-bridged steroids (CBS) and triterpenoids found in various natural sources such as green, yellow-green, and red algae, marine sponges, soft corals, ascidians, starfish, and other marine invertebrates. In addition, this group of rare lipids is [...] Read more.

This review focuses on the rare group of carbon-bridged steroids (CBS) and triterpenoids found in various natural sources such as green, yellow-green, and red algae, marine sponges, soft corals, ascidians, starfish, and other marine invertebrates. In addition, this group of rare lipids is found in amoebas, fungi, fungal endophytes, and plants. For convenience, the presented CBS and triterpenoids are divided into four groups, which include: (a) CBS and triterpenoids containing a cyclopropane group; (b) CBS and triterpenoids with cyclopropane ring in the side chain; (c) CBS and triterpenoids containing a cyclobutane group; (d) CBS and triterpenoids containing cyclopentane, cyclohexane or cycloheptane moieties. For the comparative characterization of the antitumor profile, we have added several semi- and synthetic CBS and triterpenoids, with various additional rings, to identify possible promising sources for pharmacologists and the pharmaceutical industry. About 300 CBS and triterpenoids are presented in this review, which demonstrate a wide range of biological activities, but the most pronounced antitumor profile. The review summarizes biological activities both determined experimentally and estimated using the well-known PASS software. According to the data obtained, two-thirds of CBS and triterpenoids show moderate activity levels with a confidence level of 70 to 90%; however, one third of these lipids demonstrate strong antitumor activity with a confidence level exceeding 90%. Several CBS and triterpenoids, from different lipid groups, demonstrate selective action on different types of tumor cells such as renal cancer, sarcoma, pancreatic cancer, prostate cancer, lymphocytic leukemia, myeloid leukemia, liver cancer, and genitourinary cancer with varying degrees of confidence. In addition, the review presents graphical images of the antitumor profile of both individual CBS and triterpenoids groups and individual compounds. Full article

(This article belongs to the Special Issue Pharmacological Activity and Biomedical Potential of Marine Antitumor Agents)

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15 pages, 3431 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Model-Free Approach for the Configurational Analysis of Marine Natural Products

by Matthias Köck, Michael Reggelin and Stefan Immel

Mar. Drugs 2021, 19(6), 283; https://doi.org/10.3390/md19060283 - 21 May 2021

Cited by 9 | Viewed by 3834

Abstract

The NMR-based configurational analysis of complex marine natural products is still not a routine task. Different NMR parameters are used for the assignment of the relative configuration: NOE/ROE, homo- and heteronuclear J couplings as well as anisotropic parameters. The combined distance geometry (DG) [...] Read more.

The NMR-based configurational analysis of complex marine natural products is still not a routine task. Different NMR parameters are used for the assignment of the relative configuration: NOE/ROE, homo- and heteronuclear J couplings as well as anisotropic parameters. The combined distance geometry (DG) and distance bounds driven dynamics (DDD) method allows a model-free approach for the determination of the relative configuration that is invariant to the choice of an initial starting structure and does not rely on comparisons with (DFT) calculated structures. Here, we will discuss the configurational analysis of five complex marine natural products or synthetic derivatives thereof: the cis-palau’amine derivatives 1a and 1b, tetrabromostyloguanidine (1c), plakilactone H (2), and manzamine A (3). The certainty of configurational assignments is evaluated in view of the accuracy of the NOE/ROE data available. These case studies will show the prospective breadth of application of the DG/DDD method. Full article

(This article belongs to the Special Issue Configurational and Conformational Studies on the Structures of Marine Natural Products)

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14 pages, 2451 KiB

Open AccessEditor’s ChoiceArticle

N-Amino-l-Proline Methyl Ester from an Australian Fish Gut-Derived Fungus: Challenging the Distinction between Natural Product and Artifact

by Osama G. Mohamed, Zeinab G. Khalil and Robert J. Capon

Mar. Drugs 2021, 19(3), 151; https://doi.org/10.3390/md19030151 - 12 Mar 2021

Cited by 11 | Viewed by 3307

Abstract

Further investigation into a fish gut-derived fungus Evlachovaea sp. CMB-F563, previously reported to produce the unprecedented Schiff base prolinimines A–B (1–2), revealed a new cryptic natural product, N-amino-l-proline methyl ester (5)—only the second reported [...] Read more.

Further investigation into a fish gut-derived fungus Evlachovaea sp. CMB-F563, previously reported to produce the unprecedented Schiff base prolinimines A–B (1–2), revealed a new cryptic natural product, N-amino-l-proline methyl ester (5)—only the second reported natural occurrence of an N-amino-proline, and the first from a microbial source. To enable these investigations, we developed a highly sensitive analytical derivitization methodology, using 2,4-dinitrobenzaldehyde (2,4-DNB) to cause a rapid in situ transformation of 5 to the Schiff base 9, with the latter more readily detectable by UHPLC-DAD (400 nm) and HPLC-MS analyses. Moreover, we demonstrate that during cultivation 5 is retained in fungal mycelia, and it is only when solvent extraction disrupts mycelia that 5 is released to come in contact with the furans 7–8 (which are themselves produced by thermal transformation of carbohydrates during media autoclaving prior to fungal inoculation). Significantly, on contact, 5 undergoes a spontaneous condensation with 7–8 to yield the Schiff base prolinimines 1–2, respectively. Observations made during this study prompted us to reflect on what it is to be a natural product (i.e., 5), versus an artifact (i.e., 1–2), versus a media component (i.e., 7–8). Full article

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29 pages, 1665 KiB

Open AccessEditor’s ChoiceReview

Microalgae n-3 PUFAs Production and Use in Food and Feed Industries

by Marine Remize, Yves Brunel, Joana L. Silva, Jean-Yves Berthon and Edith Filaire

Mar. Drugs 2021, 19(2), 113; https://doi.org/10.3390/md19020113 - 18 Feb 2021

Cited by 92 | Viewed by 9739

Abstract

N-3 polyunsaturated fatty acids (n-3 PUFAs), and especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are essential compounds for human health. They have been proven to act positively on a panel of diseases and have interesting anti-oxidative, anti-inflammatory or anti-cancer properties. For these [...] Read more.

N-3 polyunsaturated fatty acids (n-3 PUFAs), and especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are essential compounds for human health. They have been proven to act positively on a panel of diseases and have interesting anti-oxidative, anti-inflammatory or anti-cancer properties. For these reasons, they are receiving more and more attention in recent years, especially future food or feed development. EPA and DHA come mainly from marine sources like fish or seaweed. Unfortunately, due to global warming, these compounds are becoming scarce for humans because of overfishing and stock reduction. Although increasing in recent years, aquaculture appears insufficient to meet the increasing requirements of these healthy molecules for humans. One alternative resides in the cultivation of microalgae, the initial producers of EPA and DHA. They are also rich in biochemicals with interesting properties. After defining macro and microalgae, this review synthesizes the current knowledge on n-3 PUFAs regarding health benefits and the challenges surrounding their supply within the environmental context. Microalgae n-3 PUFA production is examined and its synthesis pathways are discussed. Finally, the use of EPA and DHA in food and feed is investigated. This work aims to define better the issues surrounding n-3 PUFA production and supply and the potential of microalgae as a sustainable source of compounds to enhance the food and feed of the future. Full article

(This article belongs to the Special Issue Marine Fatty Acids-2021)

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75 pages, 4941 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Marine Pharmacology in 2016–2017: Marine Compounds with Antibacterial, Antidiabetic, Antifungal, Anti-Inflammatory, Antiprotozoal, Antituberculosis and Antiviral Activities; Affecting the Immune and Nervous Systems, and Other Miscellaneous Mechanisms of Action

by Alejandro M. S. Mayer, Aimee J. Guerrero, Abimael D. Rodríguez, Orazio Taglialatela-Scafati, Fumiaki Nakamura and Nobuhiro Fusetani

Mar. Drugs 2021, 19(2), 49; https://doi.org/10.3390/md19020049 - 21 Jan 2021

Cited by 40 | Viewed by 7191

Abstract

The review of the 2016–2017 marine pharmacology literature was prepared in a manner similar as the 10 prior reviews of this series. Preclinical marine pharmacology research during 2016–2017 assessed 313 marine compounds with novel pharmacology reported by a growing number of investigators from [...] Read more.

The review of the 2016–2017 marine pharmacology literature was prepared in a manner similar as the 10 prior reviews of this series. Preclinical marine pharmacology research during 2016–2017 assessed 313 marine compounds with novel pharmacology reported by a growing number of investigators from 54 countries. The peer-reviewed literature reported antibacterial, antifungal, antiprotozoal, antituberculosis, and antiviral activities for 123 marine natural products, 111 marine compounds with antidiabetic and anti-inflammatory activities as well as affecting the immune and nervous system, while in contrast 79 marine compounds displayed miscellaneous mechanisms of action which upon further investigation may contribute to several pharmacological classes. Therefore, in 2016–2017, the preclinical marine natural product pharmacology pipeline generated both novel pharmacology as well as potentially new lead compounds for the growing clinical marine pharmaceutical pipeline, and thus sustained with its contributions the global research for novel and effective therapeutic strategies for multiple disease categories. Full article

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16 pages, 8950 KiB

Open AccessEditor’s ChoiceArticle

Bioactive Steroids from the Red Sea Soft Coral Sinularia polydactyla

by Mohamed A. Tammam, Lucie Rárová, Marie Kvasnicová, Gabriel Gonzalez, Ahmed M. Emam, Aldoushy Mahdy, Miroslav Strnad, Efstathia Ioannou and Vassilios Roussis

Mar. Drugs 2020, 18(12), 632; https://doi.org/10.3390/md18120632 - 10 Dec 2020

Cited by 23 | Viewed by 4038

Abstract

Six new (1, 2, 6, 8, 13, and 20) and twenty previously isolated (3–5, 7, 9–12, 14–19, and 21–26) steroids featuring thirteen different [...] Read more.

Six new (1, 2, 6, 8, 13, and 20) and twenty previously isolated (3–5, 7, 9–12, 14–19, and 21–26) steroids featuring thirteen different carbocycle motifs were isolated from the organic extract of the soft coral Sinularia polydactyla collected from the Hurghada reef in the Red Sea. The structures and the relative configurations of the isolated natural products have been determined based on extensive analysis of their NMR and MS data. The cytotoxic, anti-inflammatory, anti-angiogenic, and neuroprotective activity of compounds 3–7, 9–12, 14–20, and 22–26, as well as their effect on androgen receptor-regulated transcription was evaluated in vitro in human tumor and non-cancerous cells. Steroids 22 and 23 showed significant cytotoxicity in the low micromolar range against the HeLa and MCF7 cancer cell lines, while migration of endothelial cells was inhibited by compounds 11, 12, 22, and 23 at 20 µM. The results of the androgen receptor (AR) reporter assay showed that compound 11 exhibited the strongest inhibition of AR at 10 µM, while it is noteworthy that steroids 10, 16, and 20 displayed increased inhibition of AR with decreasing concentrations. Additionally, compounds 11 and 23 showed neuroprotective activity on neuron-like SH-SY5Y cells. Full article

(This article belongs to the Special Issue Bioactive Natural Products from the Red Sea)

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20 pages, 5856 KiB

Open AccessEditor’s ChoiceArticle

Structure Elucidation and Functional Studies of a Novel β-hairpin Antimicrobial Peptide from the Marine Polychaeta Capitella teleta

by Pavel V. Panteleev, Andrey V. Tsarev, Victoria N. Safronova, Olesia V. Reznikova, Ilia A. Bolosov, Sergei V. Sychev, Zakhar O. Shenkarev and Tatiana V. Ovchinnikova

Mar. Drugs 2020, 18(12), 620; https://doi.org/10.3390/md18120620 - 4 Dec 2020

Cited by 20 | Viewed by 3463

Abstract

Endogenous antimicrobial peptides (AMPs) are evolutionary ancient molecular factors of innate immunity that play a key role in host defense. Among the most active and stable under physiological conditions AMPs are the peptides of animal origin that adopt a β-hairpin conformation stabilized by [...] Read more.

Endogenous antimicrobial peptides (AMPs) are evolutionary ancient molecular factors of innate immunity that play a key role in host defense. Among the most active and stable under physiological conditions AMPs are the peptides of animal origin that adopt a β-hairpin conformation stabilized by disulfide bridges. In this study, a novel BRICHOS-domain related AMP from the marine polychaeta Capitella teleta, named capitellacin, was produced as the recombinant analogue and investigated. The mature capitellacin exhibits high homology with the known β-hairpin AMP family—tachyplesins and polyphemusins from the horseshoe crabs. The β-hairpin structure of the recombinant capitellacin was proved by CD and NMR spectroscopy. In aqueous solution the peptide exists as monomeric right-handed twisted β-hairpin and its structure does not reveal significant amphipathicity. Moreover, the peptide retains this conformation in membrane environment and incorporates into lipid bilayer. Capitellacin exhibits a strong antimicrobial activity in vitro against a wide panel of bacteria including extensively drug-resistant strains. In contrast to other known β-hairpin AMPs, this peptide acts apparently via non-lytic mechanism at concentrations inhibiting bacterial growth. The molecular mechanism of the peptide antimicrobial action does not seem to be related to the inhibition of bacterial translation therefore other molecular targets may be assumed. The reduced cytotoxicity against human cells and high antibacterial cell selectivity as compared to tachyplesin-1 make it an attractive candidate compound for an anti-infective drug design. Full article

(This article belongs to the Special Issue Marine Bioactive Peptides II: Structure, Function, and Therapeutic Potential)

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47 pages, 5509 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Progress in Modern Marine Biomaterials Research

by Yuliya Khrunyk, Slawomir Lach, Iaroslav Petrenko and Hermann Ehrlich

Mar. Drugs 2020, 18(12), 589; https://doi.org/10.3390/md18120589 - 25 Nov 2020

Cited by 77 | Viewed by 9073

Abstract

The growing demand for new, sophisticated, multifunctional materials has brought natural structural composites into focus, since they underwent a substantial optimization during long evolutionary selection pressure and adaptation processes. Marine biological materials are the most important sources of both inspiration for biomimetics and [...] Read more.

The growing demand for new, sophisticated, multifunctional materials has brought natural structural composites into focus, since they underwent a substantial optimization during long evolutionary selection pressure and adaptation processes. Marine biological materials are the most important sources of both inspiration for biomimetics and of raw materials for practical applications in technology and biomedicine. The use of marine natural products as multifunctional biomaterials is currently undergoing a renaissance in the modern materials science. The diversity of marine biomaterials, their forms and fields of application are highlighted in this review. We will discuss the challenges, solutions, and future directions of modern marine biomaterialogy using a thorough analysis of scientific sources over the past ten years. Full article

(This article belongs to the Special Issue Marine Biomaterials 2020)

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