Marine Drugs

19 pages, 8712 KiB

Open AccessArticle

Synthesis and Characterization of a Novel Chitosan-Based Nanoparticle–Hydrogel Composite System Promising for Skin Wound Drug Delivery

by Yueying Huang, Shuting Hao, Jiayu Chen, Mengyuan Wang, Ziheng Lin and Yanan Liu

Mar. Drugs 2024, 22(9), 428; https://doi.org/10.3390/md22090428 (registering DOI) - 21 Sep 2024

Abstract

As a natural preservative, nisin is widely used in the food industry, while its application in biomedicine is limited due to its susceptibility to interference from external conditions. In this study, a nanoparticle–hydrogel composite system was designed to encapsulate and release nisin. Nisin [...] Read more.

As a natural preservative, nisin is widely used in the food industry, while its application in biomedicine is limited due to its susceptibility to interference from external conditions. In this study, a nanoparticle–hydrogel composite system was designed to encapsulate and release nisin. Nisin nanoparticles were identified with a smooth, spherical visual morphology, particle size of 122.72 ± 4.88 nm, polydispersity coefficient of 0.473 ± 0.063, and zeta potential of 23.89 ± 0.37 mV. Based on the sample state and critical properties, three temperature-sensitive hydrogels based on chitosan were ultimately chosen with a rapid gelation time of 112 s, outstanding reticular structure, and optimal swelling ratio of 239.05 ± 7.15%. The composite system exhibited the same antibacterial properties as nisin, demonstrated by the composite system’s inhibition zone diameter of 17.06 ± 0.83 mm, compared to 20.20 ± 0.58 mm for nisin, which was attributed to the prolonged release effect of the hydrogel at the appropriate temperature. The composite system also demonstrated good biocompatibility and safety, making it suitable for application as short-term wound dressings in biomedicine due to its low hemolysis rate of less than 2%. In summary, our nanoparticle-based hydrogel composite system offers a novel application form of nisin while ensuring its stability, thereby deepening and broadening the employment of nisin. Full article

(This article belongs to the Special Issue Application of Marine Chitin and Chitosan, 3rd Edition)

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22 pages, 1225 KiB

Open AccessReview

Aquatic Biomaterial Repositories: Comprehensive Guidelines, Recommendations, and Best Practices for Their Development, Establishment, and Sustainable Operation

by Christiana Tourapi, Eleni Christoforou, Susana P. Gaudêncio and Marlen I. Vasquez

Mar. Drugs 2024, 22(9), 427; https://doi.org/10.3390/md22090427 (registering DOI) - 20 Sep 2024

Abstract

The alarming pace of species extinction severely threatens terrestrial and aquatic ecosystems, undermining the crucial ecological services vital for environmental sustainability and human well-being. Anthropogenic activities, such as urbanization, agriculture, industrialization, and those inducing climate change, intensify these risks, further imperilling biodiversity. Of [...] Read more.

The alarming pace of species extinction severely threatens terrestrial and aquatic ecosystems, undermining the crucial ecological services vital for environmental sustainability and human well-being. Anthropogenic activities, such as urbanization, agriculture, industrialization, and those inducing climate change, intensify these risks, further imperilling biodiversity. Of particular importance are aquatic organisms, pivotal in biodiscovery and biotechnology. They contribute significantly to natural product chemistry, drug development, and various biotechnological applications. To safeguard these invaluable resources, establishing and maintaining aquatic biomaterial repositories (ABRs) is imperative. This review explores the complex landscape of ABRs, emphasizing the need for standardized procedures from collection to distribution. It identifies key legislative and regulatory frameworks, such as the Nagoya Protocol and EU directives, essential for ensuring responsible and equitable biorepository operations. Drawing on extensive literature and database searches, this study compiles existing recommendations and practices into a cohesive framework with which to guide the establishment and sustainable management of ABRs. Through collaborative efforts and adherence to best practices, ABRs can play a transformative role in the future of marine biotechnology and environmental conservation. Full article

(This article belongs to the Special Issue Exploiting Marine ‘Omics’ Technologies for the Biodiscovery of Marine Natural Products)

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22 pages, 660 KiB

Open AccessReview

Immunomodulatory Effects of Halichondrin Isolated from Marine Sponges and Its Synthetic Analogs in Oncological Applications

by Dinusha Shiromala Dissanayake, Dineth Pramuditha Nagahawatta, Jung-Suck Lee and You-Jin Jeon

Mar. Drugs 2024, 22(9), 426; https://doi.org/10.3390/md22090426 (registering DOI) - 20 Sep 2024

Abstract

Marine natural products comprise unique chemical structures and vast varieties of biological activities. This review aims to summarize halichondrin, a marine natural product, and its synthetic analogs along with its therapeutic properties and mechanisms. Halichondrin and its analogs, derived from marine sponges, exhibit [...] Read more.

Marine natural products comprise unique chemical structures and vast varieties of biological activities. This review aims to summarize halichondrin, a marine natural product, and its synthetic analogs along with its therapeutic properties and mechanisms. Halichondrin and its analogs, derived from marine sponges, exhibit potent antineoplastic properties, making them promising candidates for cancer therapeutics. These compounds, characterized by their complex molecular structures, have demonstrated significant efficacy in inhibiting microtubule dynamics, leading to cell cycle arrest and apoptosis in various cancer cell lines. Several types of halichondrins such as halichondrins B, C, norhalichondrin B, and homohalichondrin B have been discovered with similar anticancer and antitumor characteristics. Since naturally available halichondrins show hurdles in synthesis, recent advancements in synthetic methodologies have enabled the development of several halichondrin analogs, such as E7389 (eribulin), which have shown improved therapeutic indices. Eribulin has shown excellent immunomodulatory properties by several mechanisms such as reprogramming tumor microenvironments, facilitating the infiltration and activation of immune cells, and inhibiting microtubule dynamics. Despite promising results, challenges remain in the synthesis and clinical application of these compounds. This review explores the mechanisms underlying the immunomodulatory activity of halichondrin and its analogs in cancer therapy, along with their clinical applications and potential for future drug development. Full article

(This article belongs to the Special Issue Marine Natural Products with Immunomodulatory Activity)

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12 pages, 2262 KiB

Open AccessPerspective

Synthesis of Marine (-)-Pelorol and Future Perspectives

by Antonio Rosales Martínez and Ignacio Rodríguez-García

Mar. Drugs 2024, 22(9), 425; https://doi.org/10.3390/md22090425 - 19 Sep 2024

Abstract

Meroterpenoid-type marine natural compounds have attracted an increasing amount of attention due to their peculiar chemical structures and their potential for the development of therapeutically important probes. Within this group of substances pelorol stands out; it is a natural compound isolated from marine [...] Read more.

Meroterpenoid-type marine natural compounds have attracted an increasing amount of attention due to their peculiar chemical structures and their potential for the development of therapeutically important probes. Within this group of substances pelorol stands out; it is a natural compound isolated from marine organisms with a unique structure and an interesting biological profile. In this article, we summarize and highlight the most interesting aspects of the synthetic procedures towards this compound, which have two common key steps. The first is the coupling of a drimanyl derivative with a compound derived from an arene. The second is a Friedel–Crafts cyclization which forms the C ring of the natural product. Despite the synthetic advances achieved so far, we consider that a more efficient synthetic procedures could be carried out, since their synthetic routes are difficult to scale up due to numerous reaction steps and the limitations imposed by the use of some reagents. In this article, we present a new and versatile retrosynthetic analysis of (-)-pelorol and analogs, which is highly desirable for their easy preparation and subsequent broad study of their biological activities. This is a retrosynthetic route that could improve those reported in the literature in terms of cost-effectiveness. Full article

(This article belongs to the Special Issue Perspectives for the Development of New Multitarget Marine Drugs)

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27 pages, 7852 KiB

Open AccessReview

Recent Advances in Anti-Inflammatory Compounds from Marine Microorganisms

by Guihua Yang, Miaoping Lin, Kumaravel Kaliaperumal, Yaqi Lu, Xin Qi, Xiaodong Jiang, Xinya Xu, Chenghai Gao, Yonghong Liu and Xiaowei Luo

Mar. Drugs 2024, 22(9), 424; https://doi.org/10.3390/md22090424 - 18 Sep 2024

Abstract

Marine microbial secondary metabolites with diversified structures have been found as promising sources of anti-inflammatory lead compounds. This review summarizes the sources, chemical structures, and pharmacological properties of anti-inflammatory natural products reported from marine microorganisms in the past three years (2021–2023). Approximately 252 [...] Read more.

Marine microbial secondary metabolites with diversified structures have been found as promising sources of anti-inflammatory lead compounds. This review summarizes the sources, chemical structures, and pharmacological properties of anti-inflammatory natural products reported from marine microorganisms in the past three years (2021–2023). Approximately 252 anti-inflammatory compounds, including 129 new ones, were predominantly obtained from marine fungi and they are structurally divided into polyketides (51.2%), terpenoids (21.0%), alkaloids (18.7%), amides or peptides (4.8%), and steroids (4.3%). This review will shed light on the development of marine microbial secondary metabolites as potential anti-inflammatory lead compounds with promising clinical applications in human health. Full article

(This article belongs to the Special Issue Marine Anti-inflammatory and Antioxidant Agents 4.0)

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12 pages, 1638 KiB

Open AccessArticle

Staurosporine as a Potential Treatment for Acanthamoeba Keratitis Using Mouse Cornea as an Ex Vivo Model

by Rubén L. Rodríguez-Expósito, Ines Sifaoui, Lizbeth Salazar-Villatoro, Carlos J. Bethencourt-Estrella, José J. Fernández, Ana R. Díaz-Marrero, Robert Sutak, Maritza Omaña-Molina, José E. Piñero and Jacob Lorenzo-Morales

Mar. Drugs 2024, 22(9), 423; https://doi.org/10.3390/md22090423 - 18 Sep 2024

Abstract

Acanthamoeba is a ubiquitous genus of amoebae that can trigger a severe and progressive ocular disease known as Acanthamoeba Keratitis (AK). Furthermore, current treatment protocols are based on the combination of different compounds that are not fully effective. Therefore, an urgent need to [...] Read more.

Acanthamoeba is a ubiquitous genus of amoebae that can trigger a severe and progressive ocular disease known as Acanthamoeba Keratitis (AK). Furthermore, current treatment protocols are based on the combination of different compounds that are not fully effective. Therefore, an urgent need to find new compounds to treat Acanthamoeba infections is clear. In the present study, we evaluated staurosporine as a potential treatment for Acanthamoeba keratitis using mouse cornea as an ex vivo model, and a comparative proteomic analysis was conducted to elucidate a mechanism of action. The obtained results indicate that staurosporine altered the conformation of actin and tubulin in treated trophozoites of A. castellanii. In addition, proteomic analysis of treated trophozoites revealed that this molecule induced overexpression and a downregulation of proteins related to key functions for Acanthamoeba infection pathways. Additionally, the ex vivo assay used validated this model for the study of the pathogenesis and therapies of AK. Finally, staurosporine eliminated the entire amoebic population and prevented the adhesion and infection of amoebae to the epithelium of treated mouse corneas. Full article

(This article belongs to the Special Issue Marine-Derived Bioactive Substances and Their Mechanisms of Action)

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38 pages, 5610 KiB

Open AccessArticle

Morphological, Toxicological, and Biochemical Characterization of Two Species of Gambierdiscus from Bahía de La Paz, Gulf of California

by Leyberth José Fernández-Herrera, Erick Julián Núñez-Vázquez, Francisco E. Hernández-Sandoval, Daniel Octavio Ceseña-Ojeda, Sara García-Davis, Andressa Teles, Marte Virgen-Félix and Dariel Tovar-Ramírez

Mar. Drugs 2024, 22(9), 422; https://doi.org/10.3390/md22090422 - 16 Sep 2024

Abstract

We describe five new isolates of two Gambierdiscus species from Bahía de La Paz in the southern Gulf of California. Batch cultures of Gambierdiscus were established for morphological characterization using light microscopy (LM) and scanning electron microscopy (SEM). Pigment and amino acid profiles [...] Read more.

We describe five new isolates of two Gambierdiscus species from Bahía de La Paz in the southern Gulf of California. Batch cultures of Gambierdiscus were established for morphological characterization using light microscopy (LM) and scanning electron microscopy (SEM). Pigment and amino acid profiles were also analyzed using high-performance liquid chromatography (HPLC-UV and HPLC-DAD). Finally, toxicity (CTX-like and MTX-like activity) was evaluated using the Artemia salina assay (ARTOX), mouse assay (MBA), marine fish assay (MFA), and fluorescent receptor binding assay (fRBA). These strains were identified as Gambierdiscus cf. caribaeus and Gambierdiscus cf. carpenteri. Toxicity for CTX-like and MTX-like activity was confirmed in all evaluated clones. Seven pigments were detected, with chlorophyll a, pyridine, Chl2, and diadinoxanthin being particularly noteworthy. For the first time, a screening of the amino acid profile of Gambierdiscus from the Pacific Ocean was conducted, which showed 14 amino acids for all strains except histidine, which was only present in G. cf. caribeaus. We report the presence of Gambierdiscus and Fukuyoa species in the Mexican Pacific, where ciguatera fish poisoning (CFP) cases have occurred. Full article

(This article belongs to the Special Issue Commemorating the Launch of the Section "Marine Toxins")

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17 pages, 5163 KiB

Open AccessArticle

Fermented Fish Collagen Attenuates Melanogenesis via Decreasing UV-Induced Oxidative Stress

by Kyung-A Byun, So Young Lee, Seyeon Oh, Sosorburam Batsukh, Jong-Won Jang, Bae-Jin Lee, Kyoung-min Rheu, Sichao Li, Min-Seok Jeong, Kuk Hui Son and Kyunghee Byun

Mar. Drugs 2024, 22(9), 421; https://doi.org/10.3390/md22090421 - 15 Sep 2024

Abstract

Excessive melanogenesis leads to hyperpigmentation-related cosmetic problems. UV exposure increases oxidative stress, which promotes melanogenesis-related signal pathways such as the PKA, microphthalmia-associated transcription factor (MITF), tyrosinase (TYR), tyrosinase-related protein-1 (TRP1), and tyrosinase-related protein-2 (TRP2) pathways. Glycine is a source of endogenous antioxidants, including [...] Read more.

Excessive melanogenesis leads to hyperpigmentation-related cosmetic problems. UV exposure increases oxidative stress, which promotes melanogenesis-related signal pathways such as the PKA, microphthalmia-associated transcription factor (MITF), tyrosinase (TYR), tyrosinase-related protein-1 (TRP1), and tyrosinase-related protein-2 (TRP2) pathways. Glycine is a source of endogenous antioxidants, including glutathione. Fermented fish collagen (FC) contains glycine; thus, we evaluated the effect of FC on decreasing melanogenesis via decreasing oxidative stress. The glycine receptor (GlyR) and glycine transporter-1 (GlyT1) levels were decreased in UV-irradiated keratinocytes; however, the expression levels of these proteins increased upon treatment with FC. The FC decreased oxidative stress, as indicated by the decreasing expression of NOX1/2/4, increased expression of GSH/GSSG, increased SOD activity, and decreased 8-OHdG expression in UV-irradiated keratinocytes. Administration of conditioned media from FC-treated keratinocytes to melanocytes led to decreased p38, PKC, MITF, TRP1, and TRP2 expression. These changes induced by the FC were also observed in UV-irradiated animal skin. FC treatment increased the expression of GlyR and GlyT, which was accompanied by decreased oxidative stress in the UV-irradiated skin. Moreover, the FC negatively regulated the melanogenesis signaling pathways, leading to decreased melanin content in the UV-irradiated skin. In conclusion, FC decreased UV-induced oxidative stress and melanogenesis in melanocytes and animal skin. FC could be used in the treatment of UV-induced hyperpigmentation problems. Full article

(This article belongs to the Special Issue Marine Cosmeceuticals)

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15 pages, 3407 KiB

Open AccessArticle

In Vitro In Silico Screening Strategy and Mechanism of Novel Tyrosinase Inhibitory Peptides from Nacre of Hyriopsis cumingii

by Haisheng Lin, Fei Li, Jiaao Kang, Shaohe Xie, Xiaoming Qin, Jialong Gao, Zhongqin Chen, Wenhong Cao, Huina Zheng and Wenkui Song

Mar. Drugs 2024, 22(9), 420; https://doi.org/10.3390/md22090420 - 15 Sep 2024

Abstract

For thousands of years, pearl and nacre powders have been important traditional Chinese medicines known for their skin whitening effects. To prepare the enzymatic hydrolysates of Hyriopsis cumingii nacre powder (NP-HCH), complex enzymatic hydrolysis by pineapple protease and of neutral protease was carried [...] Read more.

For thousands of years, pearl and nacre powders have been important traditional Chinese medicines known for their skin whitening effects. To prepare the enzymatic hydrolysates of Hyriopsis cumingii nacre powder (NP-HCH), complex enzymatic hydrolysis by pineapple protease and of neutral protease was carried out after the powder was pre-treated with a high-temperature and high-pressure method. The peptides were identified using LC-MS/MS and picked out through molecular docking and molecular dynamics simulations. Subsequently, the tyrosinase inhibitory and antioxidant properties of novel tyrosinase inhibitory peptides were investigated in vitro. In addition, the enzymatic activity of tyrosinase in B16F10 cells as well as melanin content and antioxidant enzyme levels were also examined. The results showed that a tyosinase inhibitory peptide (Tyr-Pro-Asn-Pro-Tyr, YPNPY) with an efficient IC₅₀ value of 0.545 ± 0.028 mM was identified. The in vitro interaction results showed that YPNPY is a reversible competitive inhibitor of tyrosinase, suggesting that it binds to the free enzyme. The B16F10 cell whitening test revealed that YPNPY can reduce the melanin content of B16F10 cells by directly inhibiting the activity of intracellular tyrosinase. Additionally, it indirectly affects melanin production by acting as an antioxidant. These results suggest that YPNPY could be widely used as a tyrosinase inhibitor in whitening foods and drugs. Full article

(This article belongs to the Special Issue Marine Alkaloids: Sources, Discovery, Diversity, and Bioactivities)

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14 pages, 5606 KiB

Open AccessArticle

Enantioselectivity in Vanadium-Dependent Haloperoxidases of Different Marine Sources for Sulfide Oxidation to Sulfoxides

by Yun-Han Zhang, Ya-Ting Zou, Yong-Yi Zeng, Lan Liu and Bi-Shuang Chen

Mar. Drugs 2024, 22(9), 419; https://doi.org/10.3390/md22090419 - 14 Sep 2024

Abstract

This study explores the reasons behind the variations in the enantioselectivity of the sulfoxidation of methyl phenyl sulfide by marine-derived vanadium-dependent haloperoxidases (VHPOs). Twelve new VHPOs of marine organisms were overexpressed, purified, and tested for their ability to oxidize sulfide. Most of these [...] Read more.

This study explores the reasons behind the variations in the enantioselectivity of the sulfoxidation of methyl phenyl sulfide by marine-derived vanadium-dependent haloperoxidases (VHPOs). Twelve new VHPOs of marine organisms were overexpressed, purified, and tested for their ability to oxidize sulfide. Most of these marine enzymes exhibited nonenantioselective behavior, underscoring the uniqueness of AnVBPO from the brown seaweed Ascophyllum nodosum and CpVBPO from the red seaweed Corallina pilulifera, which produce (R)- and (S)-sulfoxides, respectively. The enantioselective sulfoxidation pathway is likely due to direct oxygen transfer within the VHPO active site. This was demonstrated through molecular docking and molecular dynamics simulations, which revealed differences in the positioning of sulfide within AnVBPO and CpVBPO, thus explaining their distinct enantioselectivities. Nonenantioselective VHPOs probably follow a different oxidation pathway, initiating with sulfide oxidation to form a positively charged radical. Further insights were gained from studying the catalytic effect of VO₄³⁻ on H₂O₂-driven sulfoxidation. This research improves the understanding of VHPO-mediated sulfoxidation and aids in developing biocatalysts for sulfoxide synthesis. Full article

(This article belongs to the Special Issue Advances of Marine-Derived Enzymes)

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20 pages, 4189 KiB

Open AccessArticle

Regulation of Safracin Biosynthesis and Transport in Pseudomonas poae PMA22

by J. Gerardo Hernández Delgado, Miguel G. Acedos, Fernando de la Calle, Pilar Rodríguez, José Luis García and Beatriz Galán

Mar. Drugs 2024, 22(9), 418; https://doi.org/10.3390/md22090418 - 13 Sep 2024

Abstract

Pseudomonas poae PMA22 produces safracins, a family of compounds with potent broad-spectrum anti-bacterial and anti-tumor activities. The safracins’ biosynthetic gene cluster (BGC sac) consists of 11 ORFs organized in two divergent operons (sacABCDEFGHK and sacIJ) that are controlled by P_a [...] Read more.

Pseudomonas poae PMA22 produces safracins, a family of compounds with potent broad-spectrum anti-bacterial and anti-tumor activities. The safracins’ biosynthetic gene cluster (BGC sac) consists of 11 ORFs organized in two divergent operons (sacABCDEFGHK and sacIJ) that are controlled by P_a and P_i promoters. Contiguous to the BGC sac, we have located a gene that encodes a putative global regulator of the LysR family annotated as MexT that was originally described as a transcriptional activator of the MexEF-OprN multidrug efflux pump in Pseudomonas. Through both in vitro and in vivo experiments, we have demonstrated the involvement of the dual regulatory system MexT-MexS on the BGC sac expression acting as an activator and a repressor, respectively. The MexEF-OprN transport system of PMA22, also controlled by MexT, was shown to play a fundamental role in the metabolism of safracin. The overexpression of mexEF-oprN in PMA22 resulted in fourfold higher production levels of safracin. These results illustrate how a pleiotropic regulatory system can be critical to optimizing the production of tailored secondary metabolites, not only through direct interaction with the BGC promoters, but also by controlling their transport. Full article

(This article belongs to the Special Issue From Seaside to Bedside: Dedicated to Professor José María Fernández Sousa-Faro)

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18 pages, 7588 KiB

Open AccessArticle

Optimizing Antioxidant Potential: Factorial Design-Based Formulation of Fucoidan and Gallic Acid-Conjugated Dextran Blends

by Cynthia Haynara Ferreira Silva, Maylla Maria Correia Leite Silva, Weslley Souza Paiva, Mayara Jane Campos de Medeiros, Moacir Fernandes Queiroz, Luciana Duarte Martins Matta, Everaldo Silvino dos Santos and Hugo Alexandre Oliveira Rocha

Mar. Drugs 2024, 22(9), 417; https://doi.org/10.3390/md22090417 - 13 Sep 2024

Abstract

The role of oxidative stress in health and homeostasis has generated interest in the scientific community due to its association with cardiovascular and neurodegenerative diseases, cancer, and other diseases. Therefore, extensive research seeks to identify new exogenous antioxidant compounds for supplementation. Polysaccharides are [...] Read more.

The role of oxidative stress in health and homeostasis has generated interest in the scientific community due to its association with cardiovascular and neurodegenerative diseases, cancer, and other diseases. Therefore, extensive research seeks to identify new exogenous antioxidant compounds for supplementation. Polysaccharides are recognized for their antioxidant properties. However, polysaccharide chemical modifications are often necessary to enhance these properties. Therefore, dextran was conjugated with gallic acid (Dex-Gal) and later combined with fucoidan A (FucA) to formulate blends aimed at achieving superior antioxidant activity compared to individual polysaccharides. A factorial design was employed to combine FucA and Dex-Gal in different proportions, resulting in five blends (BLD1, BLD2, BLD3, BLD4, and BLD5). An analysis of surface graphs from in vitro antioxidant tests, including total antioxidant capacity (TAC), reducing power, and hydroxyl radical scavenging, guided the selection of BLD4 as the optimal formulation. Tests on 3T3 fibroblasts under various conditions of oxidative stress induced by hydrogen peroxide revealed that BLD4 provided enhanced protection compared to its isolated components. The BLD4 formulation, resulting from the combination of Dex-Gal and FucA, showed promise as an antioxidant strategy, outperforming its individual components and suggesting its potential as a supplement to mitigate oxidative stress in adverse health conditions. Full article

(This article belongs to the Special Issue Polysaccharides from Marine Environment)

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80 pages, 28457 KiB

Open AccessReview

A Chemical Toolbox to Unveil Synthetic Nature-Inspired Antifouling (NIAF) Compounds

by Ana Rita Neves, Sara Godinho, Catarina Gonçalves, Ana Sara Gomes, Joana R. Almeida, Madalena Pinto, Emília Sousa and Marta Correia-da-Silva

Mar. Drugs 2024, 22(9), 416; https://doi.org/10.3390/md22090416 - 12 Sep 2024

Abstract

The current scenario of antifouling (AF) strategies to prevent the natural process of marine biofouling is based in the use of antifouling paints containing different active ingredients, believed to be harmful to the marine environment. Compounds called booster biocides are being used with [...] Read more.

The current scenario of antifouling (AF) strategies to prevent the natural process of marine biofouling is based in the use of antifouling paints containing different active ingredients, believed to be harmful to the marine environment. Compounds called booster biocides are being used with copper as an alternative to the traditionally used tributyltin (TBT); however, some of them were recently found to accumulate in coastal waters at levels that are deleterious for marine organisms. More ecological alternatives were pursued, some of them based on the marine organism mechanisms’ production of specialized metabolites with AF activity. However, despite the investment in research on AF natural products and their synthetic analogues, many studies showed that natural AF alternatives do not perform as well as the traditional metal-based ones. In the search for AF agents with better performance and to understand which molecular motifs were responsible for the AF activity of natural compounds, synthetic analogues were produced and investigated for structure–AF activity relationship studies. This review is a comprehensive compilation of AF compounds synthesized in the last two decades with highlights on the data concerning their structure–activity relationship, providing a chemical toolbox for researchers to develop efficient nature-inspired AF agents. Full article

(This article belongs to the Special Issue Marine Natural Products with Antifouling Activity, 3rd Edition)

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20 pages, 7968 KiB

Open AccessArticle

Blood Coagulation Activities and Influence on DNA Condition of Alginate—Calcium Composites Prepared by Freeze-Drying Technique

by Małgorzata Świerczyńska, Paulina Król, César I. Hernández Vázquez, Klaudia Piekarska, Katarzyna Woźniak, Michał Juszczak, Zdzisława Mrozińska and Marcin H. Kudzin

Mar. Drugs 2024, 22(9), 415; https://doi.org/10.3390/md22090415 - 10 Sep 2024

Abstract

The aim of this research was to synthesize and characterize alginate–calcium composites using a freeze-drying method, with a focus on their potential applications in biomedicine. This study specifically explored the biochemical properties of these composites, emphasizing their role in blood coagulation and their [...] Read more.

The aim of this research was to synthesize and characterize alginate–calcium composites using a freeze-drying method, with a focus on their potential applications in biomedicine. This study specifically explored the biochemical properties of these composites, emphasizing their role in blood coagulation and their capacity to interact with DNA. Additionally, the research aimed to assess how the cross-linking process influences the structural and chemical characteristics of the composites. Detailed analyses, including microscopic examination, surface area assessment, and atomic absorption spectrometry, yielded significant results. The objective of this study was to examine the impact of calcium chloride concentration on the calcium content in alginate composites. Specifically, the study assessed how varying concentrations of the cross-linking solution (ranging from 0.5% to 2%) influence the calcium ion saturation within the composites. This investigation is essential for understanding the physicochemical properties of the materials, including calcium content, porosity, and specific surface area. The results are intended to identify the optimal cross-linking conditions that maximize calcium enrichment efficiency while preserving the material’s structural integrity. The study found that higher calcium chloride concentrations in alginate cross-linking improve the formation of a porous structure, enhanced by two-stage freeze-drying. Increased calcium levels led to a larger surface area and pore volume, and significantly higher calcium content. Furthermore, assays of activated partial thromboplastin time (aPTT) showed a reduction in clotting time for alginate composites containing calcium ions, indicating their potential as hemostatic agents. The aPTT test showed shorter clotting times with higher calcium ion concentrations, without enhanced activation of the extrinsic clotting pathway. The developed alginate material with calcium effectively supports hemostasis and reduces the risk of infection. The study also explored the capacity of these composites to interact with and modify the structure of plasmid DNA, underscoring their potential for future biomedical applications. Full article

(This article belongs to the Section Biomaterials of Marine Origin)

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16 pages, 3244 KiB

Open AccessArticle

Genome Analysis of a Potential Novel Vibrio Species Secreting pH- and Thermo-Stable Alginate Lyase and Its Application in Producing Alginate Oligosaccharides

by Ke Bao, Miao Yang, Qianhuan Sun, Kaishan Zhang and Huiqin Huang

Mar. Drugs 2024, 22(9), 414; https://doi.org/10.3390/md22090414 - 10 Sep 2024

Abstract

Alginate lyase is an attractive biocatalyst that can specifically degrade alginate to produce oligosaccharides, showing great potential for industrial and medicinal applications. Herein, an alginate-degrading strain HB236076 was isolated from Sargassum sp. in Qionghai, Hainan, China. The low 16S rRNA gene sequence identity [...] Read more.

Alginate lyase is an attractive biocatalyst that can specifically degrade alginate to produce oligosaccharides, showing great potential for industrial and medicinal applications. Herein, an alginate-degrading strain HB236076 was isolated from Sargassum sp. in Qionghai, Hainan, China. The low 16S rRNA gene sequence identity (<98.4%), ANI value (<71.9%), and dDDH value (<23.9%) clearly indicated that the isolate represented a potential novel species of the genus Vibrio. The genome contained two chromosomes with lengths of 3,007,948 bp and 874,895 bp, respectively, totaling 3,882,843 bp with a G+C content of 46.5%. Among 3482 genes, 3332 protein-coding genes, 116 tRNA, and 34 rRNA sequences were predicted. Analysis of the amino acid sequences showed that the strain encoded 73 carbohydrate-active enzymes (CAZymes), predicting seven PL7 (Alg1–7) and two PL17 family (Alg8, 9) alginate lyases. The extracellular alginate lyase from strain HB236076 showed the maximum activity at 50 °C and pH 7.0, with over 90% activity measured in the range of 30–60 °C and pH 6.0–10.0, exhibiting a wide range of temperature and pH activities. The enzyme also remained at more than 90% of the original activity at a wide pH range (3.0–9.0) and temperature below 50 °C for more than 2 h, demonstrating significant thermal and pH stabilities. Fe²⁺ had a good promoting effect on the alginate lyase activity at 10 mM, increasing by 3.5 times. Thin layer chromatography (TLC) and electrospray ionization mass spectrometry (ESI-MS) analyses suggested that alginate lyase in fermentation broth could catalyze sodium alginate to produce disaccharides and trisaccharides, which showed antimicrobial activity against Shigella dysenteriae, Aeromonas hydrophila, Staphylococcus aureus, Streptococcus agalactiae, and Escherichia coli. This research provided extended insights into the production mechanism of alginate lyase from Vibrio sp. HB236076, which was beneficial for further application in the preparation of pH-stable and thermo-stable alginate lyase and alginate oligosaccharides. Full article

(This article belongs to the Special Issue Marine Functional Carbohydrates: Enzymatic Manufacturing and Activity Evaluation)

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20 pages, 849 KiB

Open AccessArticle

pH-Dependent Extraction of Antioxidant Peptides from Red Seaweed Palmaria palmata: A Sequential Approach

by Sakhi Ghelichi, Ann-Dorit Moltke Sørensen, Grazielle Náthia-Neves and Charlotte Jacobsen

Mar. Drugs 2024, 22(9), 413; https://doi.org/10.3390/md22090413 - 10 Sep 2024

Abstract

This study employed a diverse approach to extract antioxidant peptides from red seaweed Palmaria palmata, recognized for its comparatively high protein content. Initially, an aqueous extraction of the entire seaweed was performed, followed by enzymatic hydrolysis of the solid residues prepared from [...] Read more.

This study employed a diverse approach to extract antioxidant peptides from red seaweed Palmaria palmata, recognized for its comparatively high protein content. Initially, an aqueous extraction of the entire seaweed was performed, followed by enzymatic hydrolysis of the solid residues prepared from the first step. The effects of three different pH levels (3, 6, and 9) during the aqueous extraction were also examined. Results indicated that the solid fraction from the sequential extraction process contained significantly higher levels of proteins and amino acids than other fractions (p < 0.05). Furthermore, the solid fractions (IC₅₀ ranging from 2.29 to 8.15 mg.mL⁻¹) demonstrated significantly greater free radical scavengers than the liquid fractions (IC₅₀ ranging from 9.03 to 10.41 mg.mL⁻¹ or not obtained at the highest concentration tested) at both stages of extraction (p < 0.05). Among the solid fractions, those produced fractions under alkaline conditions were less effective in radical scavenging than the produced fractions under acidic or neutral conditions. The fractions with most effective metal ion chelating activity were the solid fractions from the enzymatic stage, particularly at pH 3 (IC₅₀ = 0.63 ± 0.04 mg.mL⁻¹) and pH 6 (IC₅₀ = 0.89 ± 0.07 mg.mL⁻¹), which were significantly more effective than those from the initial extraction stage (p < 0.05). Despite no significant difference in the total phenolic content between these solid fractions and their corresponding liquid fractions (3.79 ± 0.05 vs. 3.48 ± 0.02 mg.mL⁻¹ at pH 3 and 2.43 ± 0.22 vs. 2.51 ± 0.00 mg.mL⁻¹ at pH 6) (p > 0.05), the observed antioxidant properties may be attributed to bioactive amino acids such as histidine, glutamic acid, aspartic acid, tyrosine, and methionine, either as free amino acids or within proteins and peptides. Full article

(This article belongs to the Special Issue Isolation, Identification and Applications of Marine Source Polysaccharides and Peptides—2nd Edition)

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14 pages, 4314 KiB

Open AccessArticle

Screening of Lipid-Reducing Activity and Cytotoxicity of the Exometabolome from Cyanobacteria

by Rúben Luz, Rita Cordeiro, Vítor Gonçalves, Vitor Vasconcelos and Ralph Urbatzka

Mar. Drugs 2024, 22(9), 412; https://doi.org/10.3390/md22090412 - 10 Sep 2024

Abstract

Cyanobacteria are rich producers of secondary metabolites, excreting some of these to the culture media. However, the exometabolome of cyanobacteria has been poorly studied, and few studies have dwelled on its characterization and bioactivity assessment. In this work, exometabolomes of 56 cyanobacterial strains [...] Read more.

Cyanobacteria are rich producers of secondary metabolites, excreting some of these to the culture media. However, the exometabolome of cyanobacteria has been poorly studied, and few studies have dwelled on its characterization and bioactivity assessment. In this work, exometabolomes of 56 cyanobacterial strains were characterized by HR-ESI-LC-MS/MS. Cytotoxicity was assessed on two carcinoma cell lines, HepG2 and HCT116, while the reduction in lipids was tested in zebrafish larvae and in a steatosis model with fatty acid-overloaded human liver cells. The exometabolome analysis using GNPS revealed many complex clusters of unique compounds in several strains, with no identifications in public databases. Three strains reduced viability in HCT116 cells, namely Tolypotrichaceae BACA0428 (30.45%), Aphanizomenonaceae BACA0025 (40.84%), and Microchaetaceae BACA0110 (46.61%). Lipid reduction in zebrafish larvae was only observed by exposure to Dulcicalothrix sp. BACA0344 (60%). The feature-based molecular network shows that this bioactivity was highly correlated with two flavanones, a compound class described in the literature to have lipid reduction activity. The exometabolome characterization of cyanobacteria strains revealed a high chemodiversity, which supports it as a source for novel bioactive compounds, despite most of the time being overlooked. Full article

(This article belongs to the Collection Bioactive Compounds from Marine Plankton)

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23 pages, 2764 KiB

Open AccessReview

Enzymes from Fishery and Aquaculture Waste: Research Trends in the Era of Artificial Intelligence and Circular Bio-Economy

by Zied Khiari

Mar. Drugs 2024, 22(9), 411; https://doi.org/10.3390/md22090411 - 10 Sep 2024

Abstract

In the era of the blue bio-economy, which promotes the sustainable utilization and exploitation of marine resources for economic growth and development, the fisheries and aquaculture industries still face huge sustainability issues. One of the major challenges of these industries is associated with [...] Read more.

In the era of the blue bio-economy, which promotes the sustainable utilization and exploitation of marine resources for economic growth and development, the fisheries and aquaculture industries still face huge sustainability issues. One of the major challenges of these industries is associated with the generation and management of wastes, which pose a serious threat to human health and the environment if not properly treated. In the best-case scenario, fishery and aquaculture waste is processed into low-value commodities such as fishmeal and fish oil. However, this renewable organic biomass contains a number of highly valuable bioproducts, including enzymes, bioactive peptides, as well as functional proteins and polysaccharides. Marine-derived enzymes are known to have unique physical, chemical and catalytic characteristics and are reported to be superior to those from plant and animal origins. Moreover, it has been established that enzymes from marine species possess cold-adapted properties, which makes them interesting from technological, economic and sustainability points of view. Therefore, this review centers around enzymes from fishery and aquaculture waste, with a special focus on proteases, lipases, carbohydrases, chitinases and transglutaminases. Additionally, the use of fishery and aquaculture waste as a substrate for the production of industrially relevant microbial enzymes is discussed. The application of emerging technologies (i.e., artificial intelligence and machine learning) in microbial enzyme production is also presented. Full article

(This article belongs to the Special Issue Enzymes from Marine By-Products and Wastes)

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15 pages, 6260 KiB

Open AccessArticle

Altechromone A Ameliorates Inflammatory Bowel Disease by Inhibiting NF-κB and NLRP3 Pathways

by Lei Li, Jing Huang, Lixin Feng, Liyan Xu, Houwen Lin, Kechun Liu, Xiaobin Li and Rongchun Wang

Mar. Drugs 2024, 22(9), 410; https://doi.org/10.3390/md22090410 - 9 Sep 2024

Abstract

Altechromone A, also known as 2,5-dimethyl-7-hydroxychromone, is a hydroxyketone containing one hydroxyl and one ketone group. In this study, we isolated Altechromone A from the marine-derived fungus Penicillium Chrysogenum (XY-14-0-4). Previous reports show that Altechromone A has various activities including tumor suppression, antibacterial, [...] Read more.

Altechromone A, also known as 2,5-dimethyl-7-hydroxychromone, is a hydroxyketone containing one hydroxyl and one ketone group. In this study, we isolated Altechromone A from the marine-derived fungus Penicillium Chrysogenum (XY-14-0-4). Previous reports show that Altechromone A has various activities including tumor suppression, antibacterial, and antiviral activities. However, there is no study about its anti-inflammatory activity in inflammatory bowel disease (IBD). Here, we assess the anti-inflammatory activity, especially in IBD, and its potential mechanism using the zebrafish model. Our results indicated that Altechromone A has anti-inflammatory activity in a CuSO₄-, tail-cutting-, and LPS-induced inflammatory model in zebrafish, respectively. In addition, Altechromone A greatly reduced the number of neutrophils, improved intestinal motility and efflux efficiency, alleviated intestinal damage, and reduced reactive oxygen species production in the TNBS-induced IBD zebrafish model. The transcriptomics sequencing and real-time qPCR indicated that Altechromone A inhibited the expression of pro-inflammatory genes including TNF-α, NF-κB, IL-1, IL-1β, IL-6, and NLRP3. Therefore, these data indicate that Altechromone A exhibits therapeutic effects in IBD by inhibiting the inflammatory response. Full article

(This article belongs to the Special Issue Zebrafish Models in Marine Drug Discovery)

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