Research

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20 pages, 2246 KiB

Open AccessArticle

Would Antarctic Marine Benthos Survive Alien Species Invasions? What Chemical Ecology May Tell Us

by Conxita Avila, Xavier Buñuel, Francesc Carmona, Albert Cotado, Oriol Sacristán-Soriano and Carlos Angulo-Preckler

Mar. Drugs 2022, 20(9), 543; https://doi.org/10.3390/md20090543 - 24 Aug 2022

Cited by 1 | Viewed by 2731

Abstract

Many Antarctic marine benthic macroinvertebrates are chemically protected against predation by marine natural products of different types. Antarctic potential predators mostly include sea stars (macropredators) and amphipod crustaceans (micropredators) living in the same areas (sympatric). Recently, alien species (allopatric) have been reported to [...] Read more.

Many Antarctic marine benthic macroinvertebrates are chemically protected against predation by marine natural products of different types. Antarctic potential predators mostly include sea stars (macropredators) and amphipod crustaceans (micropredators) living in the same areas (sympatric). Recently, alien species (allopatric) have been reported to reach the Antarctic coasts, while deep-water crabs are suggested to be more often present in shallower waters. We decided to investigate the effect of the chemical defenses of 29 representative Antarctic marine benthic macroinvertebrates from seven different phyla against predation by using non-native allopatric generalist predators as a proxy for potential alien species. The Antarctic species tested included 14 Porifera, two Cnidaria, two Annelida, one Nemertea, two Bryozooa, three Echinodermata, and five Chordata (Tunicata). Most of these Antarctic marine benthic macroinvertebrates were chemically protected against an allopatric generalist amphipod but not against an allopatric generalist crab from temperate waters. Therefore, both a possible recolonization of large crabs from deep waters or an invasion of non-native generalist crab species could potentially alter the fundamental nature of these communities forever since chemical defenses would not be effective against them. This, together with the increasing temperatures that elevate the probability of alien species surviving, is a huge threat to Antarctic marine benthos. Full article

(This article belongs to the Special Issue Tribute to Dr. Guido Cimino’s 80th Birthday and His Outstanding Achievements on Marine Natural Products)

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15 pages, 1027 KiB

Open AccessArticle

Synthesis and Antifouling Activity Evaluation of Analogs of Bromosphaerol, a Brominated Diterpene Isolated from the Red Alga Sphaerococcus coronopifolius

by Kyriakos C. Prousis, Stefanos Kikionis, Efstathia Ioannou, Silvia Morgana, Marco Faimali, Veronica Piazza, Theodora Calogeropoulou and Vassilios Roussis

Mar. Drugs 2022, 20(1), 7; https://doi.org/10.3390/md20010007 - 22 Dec 2021

Cited by 7 | Viewed by 2438

Abstract

Marine biofouling is an epibiotic biological process that affects almost any kind of submerged surface, causing globally significant economic problems mainly for the shipping industry and aquaculture companies, and its prevention so far has been associated with adverse environmental effects for non-target organisms. [...] Read more.

Marine biofouling is an epibiotic biological process that affects almost any kind of submerged surface, causing globally significant economic problems mainly for the shipping industry and aquaculture companies, and its prevention so far has been associated with adverse environmental effects for non-target organisms. Previously, we have identified bromosphaerol (1), a brominated diterpene isolated from the red alga Sphaerococcus coronopifolius, as a promising agent with significant antifouling activity, exerting strong anti-settlement activity against larvae of Amphibalanus (Balanus) amphitrite and very low toxicity. The significant antifouling activity and low toxicity of bromosphaerol (1) motivated us to explore its chemistry, aiming to optimize its antifouling potential through the preparation of a number of analogs. Following different synthetic routes, we successfully synthesized 15 structural analogs (2–16) of bromosphaerol (1), decorated with different functional groups. The anti-settlement activity (EC₅₀) and the degree of toxicity (LC₅₀) of the bromosphaerol derivatives were evaluated using cyprids and nauplii of the cirriped crustacean A. amphitrite as a model organism. Derivatives 2, 4, and 6–16 showed diverse levels of antifouling activity. Among them, compounds 9 and 13 can be considered as well-performing antifoulants, exerting their activity through a non-toxic mechanism. Full article

(This article belongs to the Special Issue Tribute to Dr. Guido Cimino’s 80th Birthday and His Outstanding Achievements on Marine Natural Products)

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14 pages, 966 KiB

Open AccessArticle

Expanding the Repertoire of Spongian-16-One Derivatives in Australian Nudibranchs of the Genus Goniobranchus and Evaluation of Their Anatomical Distribution

by Louise C. Forster, Jack K. Clegg, Karen L. Cheney and Mary J. Garson

Mar. Drugs 2021, 19(12), 680; https://doi.org/10.3390/md19120680 - 29 Nov 2021

Cited by 2 | Viewed by 2181

Abstract

Extracts of the mantle and viscera of the Indo-Pacific nudibranchs Goniobranchus aureopurpureus and Goniobranchus sp. 1 afforded 11 new diterpenoids (1–11), all of which possess a tetracyclic spongian-16-one scaffold with extensive oxidation at C-6, C-7, C-11, C-12, C-13, and/or [...] Read more.

Extracts of the mantle and viscera of the Indo-Pacific nudibranchs Goniobranchus aureopurpureus and Goniobranchus sp. 1 afforded 11 new diterpenoids (1–11), all of which possess a tetracyclic spongian-16-one scaffold with extensive oxidation at C-6, C-7, C-11, C-12, C-13, and/or C-20. The structures and relative configuration were investigated by NMR experiments, while X-ray crystallography provided the absolute configuration of 1, including a 2′S configuration for the 2-methylbutanoate substituent located at C-7. Dissection of animal tissue revealed that the mantle and viscera tissues differed in their metabolite composition with diterpenes 1–11 present in the mantle tissue of the two nudibranch species. Full article

(This article belongs to the Special Issue Tribute to Dr. Guido Cimino’s 80th Birthday and His Outstanding Achievements on Marine Natural Products)

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17 pages, 2317 KiB

Open AccessFeature PaperArticle

Diterpenoids from the Brown Alga Rugulopteryx okamurae and Their Anti-Inflammatory Activity

by Belén Cuevas, Ana I. Arroba, Carolina de los Reyes, Laura Gómez-Jaramillo, M. Carmen González-Montelongo and Eva Zubía

Mar. Drugs 2021, 19(12), 677; https://doi.org/10.3390/md19120677 - 27 Nov 2021

Cited by 15 | Viewed by 3937

Abstract

Brown algae of the Family Dictyotaceae produce an array of structurally diverse terpenoids, whose biomedical potential in the anti-inflammatory area has been scarcely explored. Herein, the chemical study of the alga Rugulopteryx okamurae has led to the isolation of ten new diterpenoids: rugukadiol [...] Read more.

Brown algae of the Family Dictyotaceae produce an array of structurally diverse terpenoids, whose biomedical potential in the anti-inflammatory area has been scarcely explored. Herein, the chemical study of the alga Rugulopteryx okamurae has led to the isolation of ten new diterpenoids: rugukadiol A (1), rugukamurals A–C (2–4), and ruguloptones A–F (6–10). The structures of the new compounds were established by spectroscopic means. Compound 1 exhibits an unprecedented diterpenoid skeleton featuring a bridged tricyclic undecane system. Compounds 2–10 belong to the secospatane class of diterpenoids and differ by the oxygenated functions that they contain. In anti-inflammatory assays, the new diterpenoid 1 and the secospatanes 5 and 10 significantly inhibited the production of the inflammatory mediator NO in LPS-stimulated microglial cells Bv.2 and macrophage cells RAW 264.7. Moreover, compounds 1 and 5 were found to strongly inhibit the expression of Nos2 and the pro-inflammatory cytokine Il1b in both immune cell lines. Full article

(This article belongs to the Special Issue Tribute to Dr. Guido Cimino’s 80th Birthday and His Outstanding Achievements on Marine Natural Products)

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9 pages, 1702 KiB

Open AccessArticle

An Alternative Approach towards C-12 Functionalized Scalaranic Sesterterpenoids Synthesis of 17-Oxo-20-norscalaran-12α,19-O-lactone

by Olga Morarescu, Marina Grinco, Veaceslav Kulciţki, Sergiu Shova and Nicon Ungur

Mar. Drugs 2021, 19(11), 636; https://doi.org/10.3390/md19110636 - 12 Nov 2021

Cited by 3 | Viewed by 1575

Abstract

Scalarane sesterterpenoids emerged as interesting bioactive natural products which were isolated extensively from marine sponges and shell-less mollusks. Some representatives were also reported recently from superior plants. Many scalarane sesterterpenoids displayed a wide spectrum of valuable properties, such as antifeedant, antimicrobial, antifungal, antitubercular, [...] Read more.

Scalarane sesterterpenoids emerged as interesting bioactive natural products which were isolated extensively from marine sponges and shell-less mollusks. Some representatives were also reported recently from superior plants. Many scalarane sesterterpenoids displayed a wide spectrum of valuable properties, such as antifeedant, antimicrobial, antifungal, antitubercular, antitumor, anti-HIV properties, cytotoxicity and stimulation of nerve growth factor synthesis, as well as anti-inflammatory activity. Due to their important biological properties, many efforts have been undertaken towards the chemical synthesis of natural scalaranes. The main synthetic challenges are connected to their complex polycyclic framework, chiral centers and different functional groups, in particular the oxygenated functional groups at the C-12 position, which are prerequisites of the biological activity of many investigated scalaranes. The current work addresses this problem and the synthesis of 17-oxo-20-norscalaran-12α,19-O-lactone is described. It was performed via the 12α-hydroxy-ent-isocopal-13(14)-en-15-al obtained from (-)-sclareol as an accessible starting material. The tetracyclic lactone framework was built following an addition strategy, which includes the intramolecular Michael addition of a diterpenic acetoacetic ester and an intramolecular aldol condensation reaction as key synthetic steps. The structure and stereochemistry of the target compound have been proven by X-Ray diffraction method. Full article

(This article belongs to the Special Issue Tribute to Dr. Guido Cimino’s 80th Birthday and His Outstanding Achievements on Marine Natural Products)

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17 pages, 1914 KiB

Open AccessArticle

Unravelling the Anti-Inflammatory and Antioxidant Potential of the Marine Sponge Cliona celata from the Portuguese Coastline

by Joana Alves, Helena Gaspar, Joana Silva, Celso Alves, Alice Martins, Fernando Teodoro, Patrícia Susano, Susete Pinteus and Rui Pedrosa

Mar. Drugs 2021, 19(11), 632; https://doi.org/10.3390/md19110632 - 12 Nov 2021

Cited by 5 | Viewed by 2713

Abstract

Inflammation is a double-edged sword, as it can have both protective effects and harmful consequences, which, combined with oxidative stress (OS), can lead to the development of deathly chronic inflammatory conditions. Over the years, research has evidenced the potential of marine sponges as [...] Read more.

Inflammation is a double-edged sword, as it can have both protective effects and harmful consequences, which, combined with oxidative stress (OS), can lead to the development of deathly chronic inflammatory conditions. Over the years, research has evidenced the potential of marine sponges as a source of effective anti-inflammatory therapeutic agents. Within this framework, the purpose of this study was to evaluate the antioxidant and the anti-inflammatory potential of the marine sponge Cliona celata. For this purpose, their organic extracts (C1–C5) and fractions were evaluated concerning their radical scavenging activity through 2,2-diphenyl-1-picrylhydrazyl radical (DPPH), ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC), and anti-inflammatory activity through a (lipopolysaccharides (LPS)-induced inflammation on RAW 264.7 cells) model. Compounds present in the two most active fractions (F5 and F13) of C4 were tentatively identified by gas chromatography coupled to mass spectrometry (GC-MS). Even though samples displayed low antioxidant activity, they presented a high anti-inflammatory capacity in the studied cellular inflammatory model when compared to the anti-inflammatory standard, dexamethasone. GC-MS analysis led to the identification of n-hexadecanoic acid, cis-9-hexadecenal, and 13-octadecenal in fraction F5, while two major compounds, octadecanoic acid and cholesterol, were identified in fraction F13. The developed studies demonstrated the high anti-inflammatory activity of the marine sponge C. celata extracts and fractions, highlighting its potential for further therapeutic applications. Full article

(This article belongs to the Special Issue Tribute to Dr. Guido Cimino’s 80th Birthday and His Outstanding Achievements on Marine Natural Products)

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Review

Jump to: Research

22 pages, 969 KiB

Open AccessReview

Marine Demospongiae: A Challenging Treasure of Bioactive Compounds

by Roberta Esposito, Serena Federico, Marco Bertolino, Valerio Zupo and Maria Costantini

Mar. Drugs 2022, 20(4), 244; https://doi.org/10.3390/md20040244 - 31 Mar 2022

Cited by 9 | Viewed by 3458

Abstract

In the last decades, it has been demonstrated that marine organisms are a substantial source of bioactive compounds with possible biotechnological applications. Marine sponges, in particular those belonging to the class of Demospongiae, have been considered among the most interesting invertebrates for their [...] Read more.

In the last decades, it has been demonstrated that marine organisms are a substantial source of bioactive compounds with possible biotechnological applications. Marine sponges, in particular those belonging to the class of Demospongiae, have been considered among the most interesting invertebrates for their biotechnological potential. In this review, particular attention is devoted to natural compounds/extracts isolated from Demospongiae and their associated microorganisms with important biological activities for pharmacological applications such as antiviral, anticancer, antifouling, antimicrobial, antiplasmodial, antifungal and antioxidant. The data here presented show that this class of sponges is an exciting source of compounds, which are worth developing into new drugs, such as avarol, a hydroquinone isolated from the marine sponge Disidea avara, which is used as an antitumor, antimicrobial and antiviral drug. Full article

(This article belongs to the Special Issue Tribute to Dr. Guido Cimino’s 80th Birthday and His Outstanding Achievements on Marine Natural Products)

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39 pages, 11268 KiB

Open AccessReview

Marine-Derived Indole Alkaloids and Their Biological and Pharmacological Activities

by Joko Tri Wibowo, Peni Ahmadi, Siti Irma Rahmawati, Asep Bayu, Masteria Yunovilsa Putra and Anake Kijjoa

Mar. Drugs 2022, 20(1), 3; https://doi.org/10.3390/md20010003 - 21 Dec 2021

Cited by 28 | Viewed by 5211

Abstract

Novel secondary metabolites from marine macroorganisms and marine-derived microorganisms have been intensively investigated in the last few decades. Several classes of compounds, especially indole alkaloids, have been a target for evaluating biological and pharmacological activities. As one of the most promising classes of [...] Read more.

Novel secondary metabolites from marine macroorganisms and marine-derived microorganisms have been intensively investigated in the last few decades. Several classes of compounds, especially indole alkaloids, have been a target for evaluating biological and pharmacological activities. As one of the most promising classes of compounds, indole alkaloids possess not only intriguing structural features but also a wide range of biological/pharmacological activities including antimicrobial, anti-inflammatory, anticancer, antidiabetic, and antiparasitic activities. This review reports the indole alkaloids isolated during the period of 2016–2021 and their relevant biological/pharmacological activities. The marine-derived indole alkaloids reported from 2016 to 2021 were collected from various scientific databases. A total of 186 indole alkaloids from various marine organisms including fungi, bacteria, sponges, bryozoans, mangroves, and algae, are described. Despite the described bioactivities, further evaluation including their mechanisms of action and biological targets is needed to determine which of these indole alkaloids are worth studying to obtain lead compounds for the development of new drugs. Full article

(This article belongs to the Special Issue Tribute to Dr. Guido Cimino’s 80th Birthday and His Outstanding Achievements on Marine Natural Products)

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