Marine Drugs

11 pages, 1026 KiB

Open AccessEditor’s ChoiceArticle

Synthesis and Antimalarial Evaluation of Halogenated Analogues of Thiaplakortone A

by Folake A. Egbewande, Brett D. Schwartz, Sandra Duffy, Vicky M. Avery and Rohan A. Davis

Mar. Drugs 2023, 21(5), 317; https://doi.org/10.3390/md21050317 - 22 May 2023

Viewed by 1297

The incorporation of bromine, iodine or fluorine into the tricyclic core structure of thiaplakortone A (1), a potent antimalarial marine natural product, is reported. Although yields were low, it was possible to synthesise a small nine-membered library using the previously synthesised [...] Read more.

The incorporation of bromine, iodine or fluorine into the tricyclic core structure of thiaplakortone A (1), a potent antimalarial marine natural product, is reported. Although yields were low, it was possible to synthesise a small nine-membered library using the previously synthesised Boc-protected thiaplakortone A (2) as a scaffold for late-stage functionalisation. The new thiaplakortone A analogues (3–11) were generated using N-bromosuccinimide, N-iodosuccinimide or a Diversinate™ reagent. The chemical structures of all new analogues were fully characterised by 1D/2D NMR, UV, IR and MS data analyses. All compounds were evaluated for their antimalarial activity against Plasmodium falciparum 3D7 (drug-sensitive) and Dd2 (drug-resistant) strains. Incorporation of halogens at positions 2 and 7 of the thiaplakortone A scaffold was shown to reduce antimalarial activity compared to the natural product. Of the new compounds, the mono-brominated analogue (compound 5) displayed the best antimalarial activity with IC₅₀ values of 0.559 and 0.058 μM against P. falciparum 3D7 and Dd2, respectively, with minimal toxicity against a human cell line (HEK293) observed at 80 μM. Of note, the majority of the halogenated compounds showed greater efficacy against the P. falciparum drug-resistant strain. Full article

(This article belongs to the Special Issue Marine Antiparasitic Agents)

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16 pages, 1600 KiB

Open AccessSystematic Review

Efficacy and Security of Tetrodotoxin in the Treatment of Cancer-Related Pain: Systematic Review and Meta-Analysis

by Miguel Á. Huerta, Javier de la Nava, Antonia Artacho-Cordón and Francisco R. Nieto

Mar. Drugs 2023, 21(5), 316; https://doi.org/10.3390/md21050316 - 21 May 2023

Cited by 2 | Viewed by 3462

Abstract

The pharmacological treatment of cancer-related pain is unsatisfactory. Tetrodotoxin (TTX) has shown analgesia in preclinical models and clinical trials, but its clinical efficacy and safety have not been quantified. For this reason, our aim was to perform a systematic review and meta-analysis of [...] Read more.

The pharmacological treatment of cancer-related pain is unsatisfactory. Tetrodotoxin (TTX) has shown analgesia in preclinical models and clinical trials, but its clinical efficacy and safety have not been quantified. For this reason, our aim was to perform a systematic review and meta-analysis of the clinical evidence that was available. A systematic literature search was conducted in four electronic databases (Medline, Web of Science, Scopus, and ClinicalTrials.gov) up to 1 March 2023 in order to identify published clinical studies evaluating the efficacy and security of TTX in patients with cancer-related pain, including chemotherapy-induced neuropathic pain. Five articles were selected, three of which were randomized controlled trials (RCTs). The number of responders to the primary outcome (≥30% improvement in the mean pain intensity) and those suffering adverse events in the intervention and placebo groups were used to calculate effect sizes using the log odds ratio. The meta-analysis showed that TTX significantly increased the number of responders (mean = 0.68; 95% CI: 0.19–1.16, p = 0.0065) and the number of patients suffering non-severe adverse events (mean = 1.13; 95% CI: 0.31–1.95, p = 0.0068). However, TTX did not increase the risk of suffering serious adverse events (mean = 0.75; 95% CI: −0.43–1.93, p = 0.2154). In conclusion, TTX showed robust analgesic efficacy but also increased the risk of suffering non-severe adverse events. These results should be confirmed in further clinical trials with higher numbers of patients. Full article

(This article belongs to the Special Issue Tetrodotoxins: Detection, Biosynthesis and Biological Effects)

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15 pages, 1158 KiB

Open AccessArticle

Purification and Molecular Characterization of Fucoidan Isolated from Ascophyllum nodosum Brown Seaweed Grown in Ireland

by Gaurav Rajauria, Rajeev Ravindran, Marco Garcia-Vaquero, Dilip K. Rai, Torres Sweeney and John O’Doherty

Mar. Drugs 2023, 21(5), 315; https://doi.org/10.3390/md21050315 - 21 May 2023

Cited by 3 | Viewed by 2375

Abstract

The present study investigates the molecular characteristics of fucoidan obtained from the brown Irish seaweed Ascophyllum nodosum, employing hydrothermal-assisted extraction (HAE) followed by a three-step purification protocol. The dried seaweed biomass contained 100.9 mg/g of fucoidan, whereas optimised HAE conditions (solvent, 0.1N [...] Read more.

The present study investigates the molecular characteristics of fucoidan obtained from the brown Irish seaweed Ascophyllum nodosum, employing hydrothermal-assisted extraction (HAE) followed by a three-step purification protocol. The dried seaweed biomass contained 100.9 mg/g of fucoidan, whereas optimised HAE conditions (solvent, 0.1N HCl; time, 62 min; temperature, 120 °C; and solid to liquid ratio, 1:30 (w/v)) yielded 417.6 mg/g of fucoidan in the crude extract. A three-step purification of the crude extract, involving solvents (ethanol, water, and calcium chloride), molecular weight cut-off filter (MWCO; 10 kDa), and solid-phase extraction (SPE), resulted in 517.1 mg/g, 562.3 mg/g, and 633.2 mg/g of fucoidan (p < 0.05), respectively. In vitro antioxidant activity, as determined by 1,1-diphenyl-2-picryl-hydrazyl radical scavenging and ferric reducing antioxidant power assays, revealed that the crude extract exhibited the highest antioxidant activity compared to the purified fractions, commercial fucoidan, and ascorbic acid standard (p < 0.05). The molecular attributes of biologically active fucoidan-rich MWCO fraction was characterised by quadruple time of flight mass spectrometry and Fourier-transform infrared (FTIR) spectroscopy. The electrospray ionisation mass spectra of purified fucoidan revealed quadruply ([M+4H]⁴⁺) and triply ([M+3H]³⁺) charged fucoidan moieties at m/z 1376 and m/z 1824, respectively, and confirmed the molecular mass 5444 Da (~5.4 kDa) from multiply charged species. The FTIR analysis of both purified fucoidan and commercial fucoidan standard exhibited O-H, C-H, and S=O stretching which are represented by bands at 3400 cm⁻¹, 2920 cm⁻¹, and 1220–1230 cm⁻¹, respectively. In conclusion, the fucoidan recovered from HAE followed by a three-step purification process was highly purified; however, purification reduced the antioxidant activity compared to the crude extract. Full article

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17 pages, 3278 KiB

Open AccessArticle

Design, Synthesis, and Biological Evaluation of Marine Lissodendrins B Analogues as Modulators of ABCB1-Mediated Multidrug Resistance

by Chaoming Wang, Jinman Zhang, Xianfeng Wei, Mengke Yang, Weiping Ma, Rilei Yu, Ming Liu and Tao Jiang

Mar. Drugs 2023, 21(5), 314; https://doi.org/10.3390/md21050314 - 20 May 2023

Cited by 1 | Viewed by 1514

Abstract

Multidrug resistance (MDR) caused by ATP-Binding Cassette Subfamily B Member 1 (ABCB1, P-glycoprotein, P-gp) is a major barrier for the success of chemotherapy in clinics. In this study, we designed and synthesized a total of 19 Lissodendrins B analogues and tested their ABCB1-mediated [...] Read more.

Multidrug resistance (MDR) caused by ATP-Binding Cassette Subfamily B Member 1 (ABCB1, P-glycoprotein, P-gp) is a major barrier for the success of chemotherapy in clinics. In this study, we designed and synthesized a total of 19 Lissodendrins B analogues and tested their ABCB1-mediated MDR reversal activity in doxorubicin (DOX)-resistant K562/ADR and MCF-7/ADR cells. Among all derivatives, compounds D₁, D₂, and D₄ with a dimethoxy-substituted tetrahydroisoquinoline fragment possessed potent synergistic effects with DOX and reversed ABCB1-mediated drug resistance. Notably, the most potent compound D₁ merits multiple activities, including low cytotoxicity, the strongest synergistic effect, and effectively reversing ABCB1-mediated drug resistance of K562/ADR (RF = 1845.76) and MCF-7/ADR cells (RF = 207.86) to DOX. As a reference substance, compound D₁ allows for additional mechanistic studies on ABCB1 inhibition. The synergistic mechanisms were mainly related to the increased intracellular accumulation of DOX via inhibiting the efflux function of ABCB1 rather than from affecting the expression level of ABCB1. These studies suggest that compound D₁ and its derivatives might be potential MDR reversal agents acting as ABCB1 inhibitors in clinical therapeutics and provide insight into a design strategy for the development of ABCB1 inhibitors. Full article

(This article belongs to the Section Marine Pharmacology)

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19 pages, 4031 KiB

Open AccessArticle

Anti-Bacterial Adhesion on Abiotic and Biotic Surfaces of the Exopolysaccharide from the Marine Bacillus licheniformis B3-15

by Vincenzo Zammuto, Antonio Spanò, Eleonora Agostino, Angela Macrì, Claudia De Pasquale, Guido Ferlazzo, Maria Giovanna Rizzo, Marco Sebastiano Nicolò, Salvatore Guglielmino and Concetta Gugliandolo

Mar. Drugs 2023, 21(5), 313; https://doi.org/10.3390/md21050313 - 20 May 2023

Cited by 7 | Viewed by 1383

Abstract

The eradication of bacterial biofilm represents a crucial strategy to prevent a clinical problem associated with microbial persistent infection. In this study we evaluated the ability of the exopolysaccharide (EPS) B3-15, produced by the marine Bacillus licheniformis B3-15, to prevent the adhesion and [...] Read more.

The eradication of bacterial biofilm represents a crucial strategy to prevent a clinical problem associated with microbial persistent infection. In this study we evaluated the ability of the exopolysaccharide (EPS) B3-15, produced by the marine Bacillus licheniformis B3-15, to prevent the adhesion and biofilm formation of Pseudomonas aeruginosa ATCC 27853 and Staphylococcus aureus ATCC 29213 on polystyrene and polyvinyl chloride surfaces. The EPS was added at different times (0, 2, 4 and 8 h), corresponding to the initial, reversible and irreversible attachment, and after the biofilm development (24 or 48 h). The EPS (300 µg/mL) impaired the initial phase, preventing bacterial adhesion even when added after 2 h of incubation, but had no effects on mature biofilms. Without exerting any antibiotic activity, the antibiofilm mechanisms of the EPS were related to the modification of the (i) abiotic surface properties, (ii) cell-surface charges and hydrophobicity, and iii) cell-to-cell aggregation. The addition of EPS downregulated the expression of genes (lecA and pslA of P. aeruginosa and clfA of S. aureus) involved in the bacterial adhesion. Moreover, the EPS reduced the adhesion of P. aeruginosa (five logs-scale) and S. aureus (one log) on human nasal epithelial cells. The EPS could represent a promising tool for the prevention of biofilm-related infections. Full article

(This article belongs to the Special Issue Marine Extremophiles)

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21 pages, 3717 KiB

Open AccessArticle

Removal of the Basic and Diazo Dyes from Aqueous Solution by the Frustules of Halamphora cf. salinicola (Bacillariophyta)

by Aleksandra Golubeva, Piya Roychoudhury, Przemysław Dąbek, Oleksandra Pryshchepa, Paweł Pomastowski, Jagoda Pałczyńska, Piotr Piszczek, Michał Gloc, Renata Dobrucka, Agnieszka Feliczak-Guzik, Izabela Nowak, Bogusław Buszewski and Andrzej Witkowski

Mar. Drugs 2023, 21(5), 312; https://doi.org/10.3390/md21050312 - 19 May 2023

Cited by 1 | Viewed by 1333

Abstract

Industrial wastes with hazardous dyes serve as a major source of water pollution, which is considered to have an enormous impact on public health. In this study, an eco-friendly adsorbent, the porous siliceous frustules extracted from the diatom species Halamphora cf. salinicola, [...] Read more.

Industrial wastes with hazardous dyes serve as a major source of water pollution, which is considered to have an enormous impact on public health. In this study, an eco-friendly adsorbent, the porous siliceous frustules extracted from the diatom species Halamphora cf. salinicola, grown under laboratory conditions, has been identified. The porous architecture and negative surface charge under a pH of 7, provided by the various functional groups via Si–O, N–H, and O–H on these surfaces, revealed by SEM, the N₂ adsorption/desorption isotherm, Zeta-potential measurement, and ATR-FTIR, respectively, made the frustules an efficient mean of removal of the diazo and basic dyes from the aqueous solutions, 74.9%, 94.02%, and 99.81% against Congo Red (CR), Crystal Violet (CV), and Malachite Green (MG), respectively. The maximum adsorption capacities were calculated from isotherms, as follows: 13.04 mg g⁻¹, 41.97 mg g⁻¹, and 33.19 mg g⁻¹ against CR, CV, and MG, respectively. Kinetic and isotherm models showed a higher correlation to Pore diffusion and Sips models for CR, and Pseudo-Second Order and Freundlich models for CV and MG. Therefore, the cleaned frustules of the thermal spring-originated diatom strain Halamphora cf. salinicola could be used as a novel adsorbent of a biological origin against anionic and basic dyes. Full article

(This article belongs to the Special Issue Ecology, Diversity and Evolution of Diatoms)

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11 pages, 1124 KiB

Open AccessArticle

Oxidative Cyclization at ortho-Position of Phenol: Improved Total Synthesis of 3-(Phenethylamino)demethyl(oxy)aaptamine

by Yuki Nakatani, Risa Kimura, Tomoyo Kimata and Naoyuki Kotoku

Mar. Drugs 2023, 21(5), 311; https://doi.org/10.3390/md21050311 - 19 May 2023

Viewed by 1254

Abstract

A shorter synthesis of the demethyl(oxy)aaptamine skeleton was developed via oxidative intramolecular cyclization of 1-(2-azidoethyl)-6-methoxyisoquinolin-7-ol followed by dehydrogenation with a hypervalent iodine reagent. This is the first example of oxidative cyclization at the ortho-position of phenol that does not involve spiro-cyclization, resulting [...] Read more.

A shorter synthesis of the demethyl(oxy)aaptamine skeleton was developed via oxidative intramolecular cyclization of 1-(2-azidoethyl)-6-methoxyisoquinolin-7-ol followed by dehydrogenation with a hypervalent iodine reagent. This is the first example of oxidative cyclization at the ortho-position of phenol that does not involve spiro-cyclization, resulting in the improved total synthesis of 3-(phenethylamino)demethyl(oxy)aaptamine, a potent anti-dormant mycobacterial agent. Full article

(This article belongs to the Special Issue Total Synthesis and Synthetic Approaches towards Marine Bioactive Natural Products and Analogues)

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Graphical abstract

14 pages, 843 KiB

Open AccessReview

Microbial Interactions between Marine Microalgae and Fungi: From Chemical Ecology to Biotechnological Possible Applications

by Chiara Lauritano and Christian Galasso

Mar. Drugs 2023, 21(5), 310; https://doi.org/10.3390/md21050310 - 19 May 2023

Cited by 2 | Viewed by 1612

Abstract

Chemical interactions have been shown to regulate several marine life processes, including selection of food sources, defense, behavior, predation, and mate recognition. These chemical communication signals have effects not only at the individual scale, but also at population and community levels. This review [...] Read more.

Chemical interactions have been shown to regulate several marine life processes, including selection of food sources, defense, behavior, predation, and mate recognition. These chemical communication signals have effects not only at the individual scale, but also at population and community levels. This review focuses on chemical interactions between marine fungi and microalgae, summarizing studies on compounds synthetized when they are cultured together. In the current study, we also highlight possible biotechnological outcomes of the synthetized metabolites, mainly for human health applications. In addition, we discuss applications for bio-flocculation and bioremediation. Finally, we point out the necessity of further investigating microalgae-fungi chemical interactions because it is a field still less explored compared to microalga–bacteria communication and, considering the promising results obtained until now, it is worthy of further research for scientific advancement in both ecology and biotechnology fields. Full article

(This article belongs to the Section Marine Chemoecology for Drug Discovery)

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19 pages, 8245 KiB

Open AccessArticle

Comparative Genomic Analysis of Cold-Water Coral-Derived Sulfitobacter faviae: Insights into Their Habitat Adaptation and Metabolism

by Shituan Lin, Yunxue Guo, Zixian Huang, Kaihao Tang and Xiaoxue Wang

Mar. Drugs 2023, 21(5), 309; https://doi.org/10.3390/md21050309 - 19 May 2023

Viewed by 1583

Abstract

Sulfitobacter is one of the major sulfite-oxidizing alphaproteobacterial groups and is often associated with marine algae and corals. Their association with the eukaryotic host cell may have important ecological contexts due to their complex lifestyle and metabolism. However, the role of Sulfitobacter in [...] Read more.

Sulfitobacter is one of the major sulfite-oxidizing alphaproteobacterial groups and is often associated with marine algae and corals. Their association with the eukaryotic host cell may have important ecological contexts due to their complex lifestyle and metabolism. However, the role of Sulfitobacter in cold-water corals remains largely unexplored. In this study, we explored the metabolism and mobile genetic elements (MGEs) in two closely related Sulfitobacter faviae strains isolated from cold-water black corals at a depth of ~1000 m by comparative genomic analysis. The two strains shared high sequence similarity in chromosomes, including two megaplasmids and two prophages, while both contained several distinct MGEs, including prophages and megaplasmids. Additionally, several toxin-antitoxin systems and other types of antiphage elements were also identified in both strains, potentially helping Sulfitobacter faviae overcome the threat of diverse lytic phages. Furthermore, the two strains shared similar secondary metabolite biosynthetic gene clusters and genes involved in dimethylsulfoniopropionate (DMSP) degradation pathways. Our results provide insight into the adaptive strategy of Sulfitobacter strains to thrive in ecological niches such as cold-water corals at the genomic level. Full article

(This article belongs to the Special Issue Genomic Studies on Marine Extreme Microbes)

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66 pages, 7625 KiB

Open AccessEditor’s ChoiceReview

Advanced Methods for Natural Products Discovery: Bioactivity Screening, Dereplication, Metabolomics Profiling, Genomic Sequencing, Databases and Informatic Tools, and Structure Elucidation

by Susana P. Gaudêncio, Engin Bayram, Lada Lukić Bilela, Mercedes Cueto, Ana R. Díaz-Marrero, Berat Z. Haznedaroglu, Carlos Jimenez, Manolis Mandalakis, Florbela Pereira, Fernando Reyes and Deniz Tasdemir

Mar. Drugs 2023, 21(5), 308; https://doi.org/10.3390/md21050308 - 19 May 2023

Cited by 16 | Viewed by 9087

Abstract

Natural Products (NP) are essential for the discovery of novel drugs and products for numerous biotechnological applications. The NP discovery process is expensive and time-consuming, having as major hurdles dereplication (early identification of known compounds) and structure elucidation, particularly the determination of the [...] Read more.

Natural Products (NP) are essential for the discovery of novel drugs and products for numerous biotechnological applications. The NP discovery process is expensive and time-consuming, having as major hurdles dereplication (early identification of known compounds) and structure elucidation, particularly the determination of the absolute configuration of metabolites with stereogenic centers. This review comprehensively focuses on recent technological and instrumental advances, highlighting the development of methods that alleviate these obstacles, paving the way for accelerating NP discovery towards biotechnological applications. Herein, we emphasize the most innovative high-throughput tools and methods for advancing bioactivity screening, NP chemical analysis, dereplication, metabolite profiling, metabolomics, genome sequencing and/or genomics approaches, databases, bioinformatics, chemoinformatics, and three-dimensional NP structure elucidation. Full article

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23 pages, 840 KiB

Open AccessReview

Ten Years of Research on Fucoidan and Cancer: Focus on Its Antiangiogenic and Antimetastatic Effects

by Eleonora Turrini, Francesca Maffei and Carmela Fimognari

Mar. Drugs 2023, 21(5), 307; https://doi.org/10.3390/md21050307 - 18 May 2023

Cited by 4 | Viewed by 3892

Abstract

Angiogenesis and metastasis represent two challenging targets to combat cancer development in the later stages of its progression. Numerous studies have indicated the important role of natural products in blocking tumor angiogenesis signaling pathways in several advanced tumors. In recent years, the marine [...] Read more.

Angiogenesis and metastasis represent two challenging targets to combat cancer development in the later stages of its progression. Numerous studies have indicated the important role of natural products in blocking tumor angiogenesis signaling pathways in several advanced tumors. In recent years, the marine polysaccharides fucoidans emerged as promising anticancer compounds showing potent antitumor activity in both in vitro and in vivo models of different types of cancers. The objective of this review is to focus on the antiangiogenic and antimetastatic activities of fucoidans with special emphasis on preclinical studies. Independently from their source, fucoidans inhibit several angiogenic regulators, primarily vascular endothelial growth factor (VEGF). A glance towards fucoidans’ ongoing clinical trials and pharmacokinetic profile is provided to present the main challenges that still need to be addressed for their bench-to-bedside translation. Full article

(This article belongs to the Special Issue Discovery of Marine-Derived Anticancer Agents)

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Graphical abstract

29 pages, 5248 KiB

Open AccessArticle

Photoprotective and Anti-Aging Properties of the Apical Frond Extracts from the Mediterranean Seaweed Ericaria amentacea

by Serena Mirata, Valentina Asnaghi, Mariachiara Chiantore, Annalisa Salis, Mirko Benvenuti, Gianluca Damonte and Sonia Scarfì

Mar. Drugs 2023, 21(5), 306; https://doi.org/10.3390/md21050306 - 18 May 2023

Cited by 2 | Viewed by 2347

Abstract

There is a growing interest in using brown algal extracts thanks to the bioactive substances they produce for adaptation to the marine benthic environment. We evaluated the anti-aging and photoprotective properties of two types of extracts (50%-ethanol and DMSO) obtained from different portions, [...] Read more.

There is a growing interest in using brown algal extracts thanks to the bioactive substances they produce for adaptation to the marine benthic environment. We evaluated the anti-aging and photoprotective properties of two types of extracts (50%-ethanol and DMSO) obtained from different portions, i.e., apices and thalli, of the brown seaweed, Ericaria amentacea. The apices of this alga, which grow and develop reproductive structures during summer when solar radiation is at its peak, were postulated to be rich in antioxidant compounds. We determined the chemical composition and pharmacological effects of their extracts and compared them to the thallus-derived extracts. All the extracts contained polyphenols, flavonoids and antioxidants and showed significant biological activities. The hydroalcoholic apices extracts demonstrated the highest pharmacological potential, likely due to the higher content of meroditerpene molecular species. They blocked toxicity in UV-exposed HaCaT keratinocytes and L929 fibroblasts and abated the oxidative stress and the production of pro-inflammatory cytokines, typically released after sunburns. Furthermore, the extracts showed anti-tyrosinase and anti-hydrolytic skin enzyme activity, counteracting the collagenase and hyaluronidase degrading activities and possibly slowing down the formation of uneven pigmentation and wrinkles in aging skin. In conclusion, the E. amentacea apices derivatives constitute ideal components for counteracting sunburn symptoms and for cosmetic anti-aging lotions. Full article

(This article belongs to the Special Issue Marine Anti-inflammatory and Antioxidant Agents 3.0)

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20 pages, 2745 KiB

Open AccessArticle

Effect of Deployment and Harvest Date on Growth and High-Value Compounds of Farmed Alaria esculenta

by Silvia Blanco, Maria Sapatinha, Mick Mackey, Julie Maguire, Simona Paolacci, Susana Gonçalves, Helena Maria Lourenço, Rogério Mendes, Narcisa Maria Bandarra and Carla Pires

Mar. Drugs 2023, 21(5), 305; https://doi.org/10.3390/md21050305 - 17 May 2023

Cited by 1 | Viewed by 1374

Abstract

Alaria esculenta is a brown seaweed farmed in many European countries for its biomass rich in useful bio compounds. This study aimed to identify the optimal growing season to maximise biomass production and quality. The seeded longlines of the brown seaweed were deployed [...] Read more.

Alaria esculenta is a brown seaweed farmed in many European countries for its biomass rich in useful bio compounds. This study aimed to identify the optimal growing season to maximise biomass production and quality. The seeded longlines of the brown seaweed were deployed in the southwest of Ireland in October and November 2019 and samples of the biomass were harvested in different dates, between March and June 2020. Biomass gain and composition, phenolic and flavonoid content (TPC and TFC) and biological activities (antioxidant and anti-hypertensive activities) of seaweed extracts prepared with Alcalase were evaluated. The biomass production was significantly higher for the line deployed in October (>20 kg·m⁻¹). In May and June, an increasing amount of epiphytes was observed on the surface of A. esculenta. The protein content of A. esculenta varied between 11.2 and 11.76% and fat content was relatively low (1.8–2.3%). Regarding the fatty acids profile, A. esculenta was rich in polyunsaturated fatty acids (PUFA), especially in eicosapentaenoic acid (EPA). The samples analysed were very rich in Na, K, Mg, Fe, Mn, Cr and Ni. The content of Cd, Pb Hg was relatively low and below the maximum levels allowed. The highest TPC and TFC were obtained in extracts prepared with A. esculenta collected in March and levels of these compounds decreased with time. In general, the highest radical scavenging activities (ABTS and DPPH), as well as chelating activities (Fe²⁺ and Cu²⁺) were observed in early spring. Extracts from A. esculenta collected in March and April presented higher ACE inhibitory activity. The extracts from seaweeds harvested in March exhibited higher biological activity. It was concluded that an earlier deployment allows for maximising growth and harvest of biomass earlier when its quality is at the highest levels. The study also confirms the high content of useful bio compounds that can be extracted from A. esculenta and used in the nutraceutical and pharmaceutical industry. Full article

(This article belongs to the Special Issue Sustainable Valorization of Seafood By-Products through Recovery of Valuable Bioactive Compounds)

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18 pages, 1192 KiB

Open AccessReview

Polyvinyl Alcohol-Chitosan Scaffold for Tissue Engineering and Regenerative Medicine Application: A Review

by Kavitha Ganesan Nathan, Krishnamurithy Genasan and Tunku Kamarul

Mar. Drugs 2023, 21(5), 304; https://doi.org/10.3390/md21050304 - 17 May 2023

Cited by 6 | Viewed by 2495

Abstract

Tissue engineering and regenerative medicine (TERM) holds great promise for addressing the growing need for innovative therapies to treat disease conditions. To achieve this, TERM relies on various strategies and techniques. The most prominent strategy is the development of a scaffold. Polyvinyl alcohol-chitosan [...] Read more.

Tissue engineering and regenerative medicine (TERM) holds great promise for addressing the growing need for innovative therapies to treat disease conditions. To achieve this, TERM relies on various strategies and techniques. The most prominent strategy is the development of a scaffold. Polyvinyl alcohol-chitosan (PVA-CS) scaffold emerged as a promising material in this field due to its biocompatibility, versatility, and ability to support cell growth and tissue regeneration. Preclinical studies showed that the PVA-CS scaffold can be fabricated and tailored to fit the specific needs of different tissues and organs. Additionally, PVA-CS can be combined with other materials and technologies to enhance its regenerative capabilities. Furthermore, PVA-CS represents a promising therapeutic solution for developing new and innovative TERM therapies. Therefore, in this review, we summarized the potential role and functions of PVA-CS in TERM applications. Full article

(This article belongs to the Special Issue Collagen and Chitin from Marine Resources and Their Interdisciplinary Applications)

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15 pages, 3868 KiB

Open AccessArticle

Tisochrysis lutea F&M-M36 Mitigates Risk Factors of Metabolic Syndrome and Promotes Visceral Fat Browning through β3-Adrenergic Receptor/UCP1 Signaling

by Mario D’Ambrosio, Elisabetta Bigagli, Lorenzo Cinci, Manuela Gencarelli, Sofia Chioccioli, Natascia Biondi, Liliana Rodolfi, Alberto Niccolai, Francesca Zambelli, Annunziatina Laurino, Laura Raimondi, Mario R. Tredici and Cristina Luceri

Mar. Drugs 2023, 21(5), 303; https://doi.org/10.3390/md21050303 - 17 May 2023

Cited by 2 | Viewed by 1560

Abstract

Pre-metabolic syndrome (pre-MetS) may represent the best transition phase to start treatments aimed at reducing cardiometabolic risk factors of MetS. In this study, we investigated the effects of the marine microalga Tisochrysis lutea F&M-M36 (T. lutea) on cardiometabolic components of pre-MetS [...] Read more.

Pre-metabolic syndrome (pre-MetS) may represent the best transition phase to start treatments aimed at reducing cardiometabolic risk factors of MetS. In this study, we investigated the effects of the marine microalga Tisochrysis lutea F&M-M36 (T. lutea) on cardiometabolic components of pre-MetS and its underlying mechanisms. Rats were fed a standard (5% fat) or a high-fat diet (20% fat) supplemented or not with 5% of T. lutea or fenofibrate (100 mg/Kg) for 3 months. Like fenofibrate, T. lutea decreased blood triglycerides (p < 0.01) and glucose levels (p < 0.01), increased fecal lipid excretion (p < 0.05) and adiponectin (p < 0.001) without affecting weight gain. Unlike fenofibrate, T. lutea did not increase liver weight and steatosis, reduced renal fat (p < 0.05), diastolic (p < 0.05) and mean arterial pressure (p < 0.05). In visceral adipose tissue (VAT), T. lutea, but not fenofibrate, increased the β3-adrenergic receptor (β3ADR) (p < 0.05) and Uncoupling protein 1 (UCP-1) (p < 0.001) while both induced glucagon-like peptide-1 receptor (GLP1R) protein expression (p < 0.001) and decreased interleukin (IL)-6 and IL-1β gene expression (p < 0.05). Pathway analysis on VAT whole-gene expression profiles showed that T. lutea up-regulated energy-metabolism-related genes and down-regulated inflammatory and autophagy pathways. The multitarget activity of T. lutea suggests that this microalga could be useful in mitigating risk factors of MetS. Full article

(This article belongs to the Special Issue Marine Anti-inflammatory and Antioxidant Agents 3.0)

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12 pages, 2353 KiB

Open AccessArticle

Fucoidan from Fucus vesiculosus Inhibits Inflammatory Response, Both In Vitro and In Vivo

by Lingzhi Wang, Catarina Oliveira, Qiu Li, Andreia S. Ferreira, Cláudia Nunes, Manuel A. Coimbra, Rui L. Reis, Albino Martins, Chunming Wang, Tiago H. Silva and Yanxian Feng

Mar. Drugs 2023, 21(5), 302; https://doi.org/10.3390/md21050302 - 17 May 2023

Cited by 2 | Viewed by 1532

Abstract

Fucoidan has been reported to present diverse bioactivities, but each extract has specific features from which a particular biological activity, such as immunomodulation, must be confirmed. In this study a commercially available pharmaceutical-grade fucoidan extracted from Fucus vesiculosus, FE, was characterized and [...] Read more.

Fucoidan has been reported to present diverse bioactivities, but each extract has specific features from which a particular biological activity, such as immunomodulation, must be confirmed. In this study a commercially available pharmaceutical-grade fucoidan extracted from Fucus vesiculosus, FE, was characterized and its anti-inflammatory potential was investigated. Fucose was the main monosaccharide (90 mol%) present in the studied FE, followed by uronic acids, galactose, and xylose that were present at similar values (3.8–2.4 mol%). FE showed a molecular weight of 70 kDa and a sulfate content of around 10%. The expression of cytokines by mouse bone-marrow-derived macrophages (BMDMs) revealed that the addition of FE upregulated the expression of CD206 and IL-10 by about 28 and 22 fold, respectively, in respect to control. This was corroborated in a stimulated pro-inflammatory situation, with the higher expression (60 fold) of iNOS being almost completely reversed by the addition of FE. FE was also capable of reverse LPS-caused inflammation in an in vivo mouse model, including by reducing macrophage activation by LPS from 41% of positive CD11C to 9% upon fucoidan injection. Taken together, the potential of FE as an anti-inflammatory agent was validated, both in vitro and in vivo. Full article

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14 pages, 1365 KiB

Open AccessArticle

Elicitor Activity of Low-Molecular-Weight Alginates Obtained by Oxidative Degradation of Alginates Extracted from Sargassum muticum and Cystoseira myriophylloides

by Meriem Aitouguinane, Zainab El Alaoui-Talibi, Halima Rchid, Imen Fendri, Slim Abdelkafi, Mohamed Didi Ould El-Hadj, Zakaria Boual, Didier Le Cerf, Christophe Rihouey, Christine Gardarin, Pascal Dubessay, Philippe Michaud, Guillaume Pierre, Cédric Delattre and Cherkaoui El Modafar

Mar. Drugs 2023, 21(5), 301; https://doi.org/10.3390/md21050301 - 16 May 2023

Cited by 3 | Viewed by 1243

Abstract

Alginates extracted from two Moroccan brown seaweeds and their derivatives were investigated for their ability to induce phenolic metabolism in the roots and leaves of tomato seedlings. Sodium alginates (ALSM and ALCM) were extracted from the brown seaweeds Sargassum muticum and Cystoseira myriophylloides [...] Read more.

Alginates extracted from two Moroccan brown seaweeds and their derivatives were investigated for their ability to induce phenolic metabolism in the roots and leaves of tomato seedlings. Sodium alginates (ALSM and ALCM) were extracted from the brown seaweeds Sargassum muticum and Cystoseira myriophylloides, respectively. Low-molecular-weight alginates (OASM and OACM) were obtained after radical hydrolysis of the native alginates. Elicitation was carried out by foliar spraying 20 mL of aqueous solutions (1 g/L) on 45-day-old tomato seedlings. Elicitor capacities were evaluated by monitoring phenylalanine ammonia-lyase (PAL) activity, polyphenols, and lignin production in the roots and leaves after 0, 12, 24, 48, and 72 h of treatment. The molecular weights (M_w) of the different fractions were 202 kDa for ALSM, 76 kDa for ALCM, 19 kDa for OACM, and 3 kDa for OASM. FTIR analysis revealed that the structures of OACM and OASM did not change after oxidative degradation of the native alginates. These molecules showed their differential capacity to induce natural defenses in tomato seedlings by increasing PAL activity and through the accumulation of polyphenol and lignin content in the leaves and roots. The oxidative alginates (OASM and OACM) exhibited an effective induction of the key enzyme of phenolic metabolism (PAL) compared to the alginate polymers (ALSM and ALCM). These results suggest that low-molecular-weight alginates may be good candidates for stimulating the natural defenses of plants. Full article

(This article belongs to the Special Issue Bioactive Polysaccharides from Seaweeds)

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17 pages, 1055 KiB

Open AccessReview

Immunomodulatory, Antioxidant, Anticancer, and Pharmacokinetic Activity of Ulvan, a Seaweed-Derived Sulfated Polysaccharide: An Updated Comprehensive Review

by Biswajita Pradhan, Prajna Paramita Bhuyan and Jang-Seu Ki

Mar. Drugs 2023, 21(5), 300; https://doi.org/10.3390/md21050300 - 16 May 2023

Cited by 13 | Viewed by 2690

Abstract

Cancer is one of the most worldwide spread diseases and causes maximum death. Treatment of cancer depends on the host immune system and the type of drugs. The inefficiency of conventional cancer treatments as a result of drug resistance, nontargeted delivery, and chemotherapy-related [...] Read more.

Cancer is one of the most worldwide spread diseases and causes maximum death. Treatment of cancer depends on the host immune system and the type of drugs. The inefficiency of conventional cancer treatments as a result of drug resistance, nontargeted delivery, and chemotherapy-related negative side effects has caused bioactive phytochemicals to come into focus. As a result, recent years have seen an increase in research into screening and identifying natural compounds with anticancer properties. Recent studies on the isolation and use of polysaccharides derived from various marine algal species have revealed a variety of biological activities, including antioxidant and anticancer properties. Ulvan is a polysaccharide derived from various green seaweeds of the Ulva species in the family Ulvaceae. It has been demonstrated to have potent anticancer and anti-inflammatory properties through the modulation of antioxidants. It is vital to understand the mechanisms underlying the biotherapeutic activities of Ulvan in cancer and its role in immunomodulation. In this context, we reviewed the anticancer effects of ulvan based on its apoptotic effects and immunomodulatory activity. Additionally, we also focused on its pharmacokinetic studies in this review. Ulvan is the most conceivable candidate for use as a cancer therapeutic agent and could be used to boost immunity. Moreover, it may be established as an anticancer drug once its mechanisms of action are understood. Due to its high food and nutritive values, it can be used as a possible dietary supplement for cancer patients in the near future. This review may provide fresh perspectives on the potential novel role of ulvan, reveal a brand-new cancer-prevention strategy, and improve human health. Full article

(This article belongs to the Special Issue The Mechanisms of Action of Bioactive Marine Natural Products)

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20 pages, 1063 KiB

Open AccessReview

Extraction, Modification and Biomedical Application of Agarose Hydrogels: A Review

by Feng Jiang, Xin-Wei Xu, Fu-Quan Chen, Hui-Fen Weng, Jun Chen, Yi Ru, Qiong Xiao and An-Feng Xiao

Mar. Drugs 2023, 21(5), 299; https://doi.org/10.3390/md21050299 - 14 May 2023

Cited by 10 | Viewed by 4669

Abstract

Numerous compounds present in the ocean are contributing to the development of the biomedical field. Agarose, a polysaccharide derived from marine red algae, plays a vital role in biomedical applications because of its reversible temperature-sensitive gelling behavior, excellent mechanical properties, and high biological [...] Read more.

Numerous compounds present in the ocean are contributing to the development of the biomedical field. Agarose, a polysaccharide derived from marine red algae, plays a vital role in biomedical applications because of its reversible temperature-sensitive gelling behavior, excellent mechanical properties, and high biological activity. Natural agarose hydrogel has a single structural composition that prevents it from adapting to complex biological environments. Therefore, agarose can be developed into different forms through physical, biological, and chemical modifications, enabling it to perform optimally in different environments. Agarose biomaterials are being increasingly used for isolation, purification, drug delivery, and tissue engineering, but most are still far from clinical approval. This review classifies and discusses the preparation, modification, and biomedical applications of agarose, focusing on its applications in isolation and purification, wound dressings, drug delivery, tissue engineering, and 3D printing. In addition, it attempts to address the opportunities and challenges associated with the future development of agarose-based biomaterials in the biomedical field. It should help to rationalize the selection of the most suitable functionalized agarose hydrogels for specific applications in the biomedical industry. Full article

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

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19 pages, 10468 KiB

Open AccessArticle

New Insights into the Mechanism of Ulva pertusa on Colitis in Mice: Modulation of the Pain and Immune System

by Alessio Ardizzone, Deborah Mannino, Anna Paola Capra, Alberto Repici, Alessia Filippone, Emanuela Esposito and Michela Campolo

Mar. Drugs 2023, 21(5), 298; https://doi.org/10.3390/md21050298 - 13 May 2023

Cited by 6 | Viewed by 1543

Abstract

Inflammatory bowel diseases (IBDs) involving Crohn’s disease (CD) and ulcerative colitis (UC) are gastrointestinal (GI) disorders in which abdominal pain, discomfort, and diarrhea are the major symptoms. The immune system plays an important role in the pathogenesis of IBD and, as indicated by [...] Read more.

Inflammatory bowel diseases (IBDs) involving Crohn’s disease (CD) and ulcerative colitis (UC) are gastrointestinal (GI) disorders in which abdominal pain, discomfort, and diarrhea are the major symptoms. The immune system plays an important role in the pathogenesis of IBD and, as indicated by several clinical studies, both innate and adaptative immune response has the faculty to induce gut inflammation in UC patients. An inappropriate mucosal immune response to normal intestinal constituents is a main feature of UC, thus leading to an imbalance in local pro- and anti-inflammatory species. Ulva pertusa, a marine green alga, is known for its important biological properties, which could represent a source of beneficial effects in various human pathologies. We have already demonstrated the anti-inflammatory, antioxidant, and antiapoptotic effects of an Ulva pertusa extract in a murine model of colitis. In this study, we aimed to examine thoroughly Ulva pertusa immunomodulatory and pain-relieving properties. Colitis was induced by using the DNBS model (4 mg in 100 μL of 50% ethanol), whereas Ulva pertusa was administered daily at the dosage of 50 and 100 mg/kg by oral gavage. Ulva pertusa treatments have been shown to relieve abdominal pain while modulating innate and adaptative immune-inflammatory responses. This powerful immunomodulatory activity was specifically linked with TLR4 and NLRP3 inflammasome modulation. In conclusion, our data suggest Ulva pertusa as a valid approach to counteract immune dysregulation and abdominal discomfort in IBD. Full article

(This article belongs to the Special Issue Marine Immunomodulatory Compounds)

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24 pages, 5012 KiB

Open AccessArticle

Sargassum natans I Algae: An Alternative for a Greener Approach for the Synthesis of ZnO Nanostructures with Biological and Environmental Applications

by Jose Luis López-Miranda, Fabian Mares-Briones, Gustavo A. Molina, M. A. González-Reyna, Isaac Velázquez-Hernández, Beatriz Liliana España-Sánchez, Rodolfo Silva, Rodrigo Esparza and Miriam Estévez

Mar. Drugs 2023, 21(5), 297; https://doi.org/10.3390/md21050297 - 13 May 2023

Cited by 4 | Viewed by 1977

Abstract

In this work, the influence of the Sargassum natans I alga extract on the morphological characteristics of synthesized ZnO nanostructures, with potential biological and environmental applications, was evaluated. For this purpose, different ZnO geometries were synthesized by the co-precipitation method, using Sargassum natans [...] Read more.

In this work, the influence of the Sargassum natans I alga extract on the morphological characteristics of synthesized ZnO nanostructures, with potential biological and environmental applications, was evaluated. For this purpose, different ZnO geometries were synthesized by the co-precipitation method, using Sargassum natans I alga extract as stabilizing agent. Four extract volumes (5, 10, 20, and 50 mL) were evaluated to obtain the different nanostructures. Moreover, a sample by chemical synthesis, without the addition of extract, was prepared. The characterization of the ZnO samples was carried out by UV-Vis spectroscopy, FT-IR spectroscopy, X-ray diffraction, and scanning electron microscopy. The results showed that the Sargassum alga extract has a fundamental role in the stabilization process of the ZnO nanoparticles. In addition, it was shown that the increase in the Sargassum alga extract leads to preferential growth and arrangement, obtaining well-defined shaped particles. ZnO nanostructures demonstrated significant anti-inflammatory response by the in vitro egg albumin protein denaturation for biological purposes. Additionally, quantitative antibacterial analysis (AA) showed that the ZnO nanostructures synthesized with 10 and 20 mL of extract demonstrated high AA against Gram (+) S. aureus and moderate AA behavior against Gram (-) P. aeruginosa, depending on the ZnO arrangement induced by the Sargassum natans I alga extract and the nanoparticles’ concentration (ca. 3200 µg/mL). Additionally, ZnO samples were evaluated as photocatalytic materials through the degradation of organic dyes. Complete degradation of both methyl violet and malachite green were achieved using the ZnO sample synthesized with 50 mL of extract. In all cases, the well-defined morphology of ZnO induced by the Sargassum natans I alga extract played a key role in the combined biological/environmental performance. Full article

(This article belongs to the Special Issue Nanoparticles Synthesis with Marine Substances)

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15 pages, 6315 KiB

Open AccessArticle

Citrinin Is a Potential Quorum Sensing Inhibitor against Pseudomonas aeruginosa

by Hongrui Ji, Lu Zhao, Kaiwen Lv, Yuzhu Zhang, Haibo Gao, Qianhong Gong and Wengong Yu

Mar. Drugs 2023, 21(5), 296; https://doi.org/10.3390/md21050296 - 12 May 2023

Viewed by 1639

Abstract

Pseudomonas aeruginosa is an opportunistic pathogen that infects patients by regulating virulence factors and biofilms through a quorum sensing (QS) system to protect itself from antibiotics and environmental stress. Therefore, the development of quorum sensing inhibitors (QSIs) is expected to become a new [...] Read more.

Pseudomonas aeruginosa is an opportunistic pathogen that infects patients by regulating virulence factors and biofilms through a quorum sensing (QS) system to protect itself from antibiotics and environmental stress. Therefore, the development of quorum sensing inhibitors (QSIs) is expected to become a new strategy for studying drug resistance to P. aeruginosa infections. Marine fungi are valuable resources for screening QSIs. A marine fungus, Penicillium sp. JH1, with anti-QS activity was isolated from the offshore waters of Qingdao (China), and citrinin, a novel QSI, was purified from secondary metabolites of this fungus. Citrinin could significantly inhibit the production of violacein in Chromobacterium violaceum CV12472 and the production of three virulence factors (elastase, rhamnolipid and pyocyanin) in P. aeruginosa PAO1. It could also inhibit the biofilm formation and motility of PAO1. In addition, citrinin downregulated the transcript levels of nine genes (lasI, rhlI, pqsA, lasR, rhlR, pqsR, lasB, rhlA and phzH) associated with QS. Molecular docking results showed that citrinin bound to PqsR and LasR with better affinity than the natural ligands. This study laid a foundation for the further study of the structure optimization and structure–activity relationship of citrinin. Full article

(This article belongs to the Section Marine Chemoecology for Drug Discovery)

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30 pages, 7419 KiB

Open AccessArticle

A Screening Approach to Assess the Impact of Various Commercial Sources of Crude Marine λ-Carrageenan on the Production of Oligosaccharides with Anti-heparanase and Anti-migratory Activities

by Chanez Manseur, Hugo Groult, Manon Porta, Pierre-Edouard Bodet, Rachida Mersni-Achour, Raphaëlle Petit, Samir Ali-Moussa, Benjamin Musnier, Didier Le Cerf, Tony Varacavoudin, Oualid Haddad, Angela Sutton, Cíntia Emi Yanaguibashi Leal, Edilson Beserra Alencar-Filho, Jean-Marie Piot, Nicolas Bridiau, Thierry Maugard and Ingrid Fruitier-Arnaudin

Mar. Drugs 2023, 21(5), 295; https://doi.org/10.3390/md21050295 - 11 May 2023

Viewed by 1748

Abstract

Oligosaccharides derived from λ-carrageenan (λ-COs) are gaining interest in the cancer field. They have been recently reported to regulate heparanase (HPSE) activity, a protumor enzyme involved in cancer cell migration and invasion, making them very promising molecules for new therapeutic applications. However, one [...] Read more.

Oligosaccharides derived from λ-carrageenan (λ-COs) are gaining interest in the cancer field. They have been recently reported to regulate heparanase (HPSE) activity, a protumor enzyme involved in cancer cell migration and invasion, making them very promising molecules for new therapeutic applications. However, one of the specific features of commercial λ-carrageenan (λ-CAR) is that they are heterogeneous mixtures of different CAR families, and are named according to the thickening-purpose final-product viscosity which does not reflect the real composition. Consequently, this can limit their use in a clinical applications. To address this issue, six commercial λ-CARs were compared and differences in their physiochemical properties were analyzed and shown. Then, a H₂O₂-assisted depolymerization was applied to each commercial source, and number- and weight-averaged molar masses (M_n and M_w) and sulfation degree (DS) of the λ-COs produced over time were determined. By adjusting the depolymerization time for each product, almost comparable λ-CO formulations could be obtained in terms of molar masses and DS, which ranged within previously reported values suitable for antitumor properties. However, when the anti-HPSE activity of these new λ-COs was screened, small changes that could not be attributed only to their small length or DS changes between them were found, suggesting a role of other features, such as differences in the initial mixture composition. Further structural MS and NMR analysis revealed qualitative and semi-quantitative differences between the molecular species, especially in the proportion of the anti-HPSE λ-type, other CARs types and adjuvants, and it also showed that H₂O₂-based hydrolysis induced sugar degradation. Finally, when the effects of λ-COs were assessed in an in vitro migration cell-based model, they seemed more related to the proportion of other CAR types in the formulation than to their λ-type-dependent anti-HPSE activity. Full article

(This article belongs to the Special Issue Extraction, Characterization and Applications of Marine Polysaccharides)

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11 pages, 624 KiB

Open AccessArticle

Mineral Bioaccessibility and Antioxidant Capacity of Protein Hydrolysates from Salmon (Salmo salar) and Mackerel (Scomber scombrus) Backbones and Heads

by Beatriz de la Fuente, Tone Aspevik, Francisco J. Barba, Katerina Kousoulaki and Houda Berrada

Mar. Drugs 2023, 21(5), 294; https://doi.org/10.3390/md21050294 - 11 May 2023

Cited by 3 | Viewed by 1596

Abstract

Information on the bioaccessibility of minerals is essential to consider a food ingredient as a potential mineral fortifier. In this study, the mineral bioaccessibility of protein hydrolysates from salmon (Salmo salar) and mackerel (Scomber scombrus) backbones and heads was [...] Read more.

Information on the bioaccessibility of minerals is essential to consider a food ingredient as a potential mineral fortifier. In this study, the mineral bioaccessibility of protein hydrolysates from salmon (Salmo salar) and mackerel (Scomber scombrus) backbones and heads was evaluated. For this purpose, the hydrolysates were submitted to simulated gastrointestinal digestion (INFOGEST method), and the mineral content was analyzed before and after the digestive process. Ca, Mg, P, Fe, Zn, and Se were then determined using an inductively coupled plasma spectrometer mass detector (ICP-MS). The highest bioaccessibility of minerals was found in salmon and mackerel head hydrolysates for Fe (≥100%), followed by Se in salmon backbone hydrolysates (95%). The antioxidant capacity of all protein hydrolysate samples, which was measured by Trolox Equivalent Antioxidant Capacity (TEAC), increased (10–46%) after in vitro digestion. The heavy metals As, Hg, Cd, and Pb were determined (ICP-MS) in the raw hydrolysates to confirm the harmlessness of these products. Except for Cd in mackerel hydrolysates, all toxic elements were below the legislation levels for fish commodities. These results suggest the possibility of using protein hydrolysates from salmon and mackerel backbones and heads for food mineral fortification, as well as the need to verify their safety. Full article

(This article belongs to the Special Issue High-Value Compounds from Marine Unutilized Resources)

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10 pages, 2044 KiB

Open AccessArticle

Diketopiperazine Alkaloids and Bisabolene Sesquiterpenoids from Aspergillus versicolor AS-212, an Endozoic Fungus Associated with Deep-Sea Coral of Magellan Seamounts

by Yu-Liang Dong, Xiao-Ming Li, Xiao-Shan Shi, Yi-Ran Wang, Bin-Gui Wang and Ling-Hong Meng

Mar. Drugs 2023, 21(5), 293; https://doi.org/10.3390/md21050293 - 10 May 2023

Cited by 1 | Viewed by 1346

Abstract

Two new quinazolinone diketopiperazine alkaloids, including versicomide E (2) and cottoquinazoline H (4), together with ten known compounds (1, 3, and 5–12) were isolated and identified from Aspergillus versicolor AS-212, an endozoic fungus [...] Read more.

Two new quinazolinone diketopiperazine alkaloids, including versicomide E (2) and cottoquinazoline H (4), together with ten known compounds (1, 3, and 5–12) were isolated and identified from Aspergillus versicolor AS-212, an endozoic fungus associated with the deep-sea coral Hemicorallium cf. imperiale, which was collected from the Magellan Seamounts. Their chemical structures were determined by an extensive interpretation of the spectroscopic and X-ray crystallographic data as well as specific rotation calculation, ECD calculation, and comparison of their ECD spectra. The absolute configurations of (−)-isoversicomide A (1) and cottoquinazoline A (3) were not assigned in the literature reports and were solved in the present work by single-crystal X-ray diffraction analysis. In the antibacterial assays, compound 3 exhibited antibacterial activity against aquatic pathogenic bacteria Aeromonas hydrophilia with an MIC value of 18.6 μM, while compounds 4 and 8 exhibited inhibitory effects against Vibrio harveyi and V. parahaemolyticus with MIC values ranging from 9.0 to 18.1 μM. Full article

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

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13 pages, 390 KiB

Open AccessReview

Microalgae from Cold Environments and Their Possible Biotechnological Applications

by Eleonora Montuori, Maria Saggiomo and Chiara Lauritano

Mar. Drugs 2023, 21(5), 292; https://doi.org/10.3390/md21050292 - 08 May 2023

Cited by 4 | Viewed by 1667

Abstract

Cold environments include deep ocean, alpine, and polar areas. Even if the cold conditions are harsh and extreme for certain habitats, various species have been adapted to survive in them. Microalgae are among the most abundant microbial communities which have adapted to live [...] Read more.

Cold environments include deep ocean, alpine, and polar areas. Even if the cold conditions are harsh and extreme for certain habitats, various species have been adapted to survive in them. Microalgae are among the most abundant microbial communities which have adapted to live in low light, low temperature, and ice coverage conditions typical of cold environments by activating different stress-responsive strategies. These species have been shown to have bioactivities with possible exploitation capabilities for human applications. Even if they are less explored compared to species living in more accessible sites, various activities have been highlighted, such as antioxidant and anticancer activities. This review is focused on summarizing these bioactivities and discussing the possible exploitation of cold-adapted microalgae. Thanks to the possibility of mass cultivating algae in controlled photobioreactors, eco-sustainable exploitation is in fact possible by sampling a few microalgal cells without impacting the environment. Full article

(This article belongs to the Section Marine Chemoecology for Drug Discovery)

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17 pages, 3573 KiB

Open AccessReview

Theonella: A Treasure Trove of Structurally Unique and Biologically Active Sterols

by Carmen Festa, Simona De Marino, Angela Zampella and Stefano Fiorucci

Mar. Drugs 2023, 21(5), 291; https://doi.org/10.3390/md21050291 - 08 May 2023

Viewed by 1439

Abstract

The marine environment is considered a vast source in the discovery of structurally unique bioactive secondary metabolites. Among marine invertebrates, the sponge Theonella spp. represents an arsenal of novel compounds ranging from peptides, alkaloids, terpenes, macrolides, and sterols. In this review, we summarize [...] Read more.

The marine environment is considered a vast source in the discovery of structurally unique bioactive secondary metabolites. Among marine invertebrates, the sponge Theonella spp. represents an arsenal of novel compounds ranging from peptides, alkaloids, terpenes, macrolides, and sterols. In this review, we summarize the recent reports on sterols isolated from this amazing sponge, describing their structural features and peculiar biological activities. We also discuss the total syntheses of solomonsterols A and B and the medicinal chemistry modifications on theonellasterol and conicasterol, focusing on the effect of chemical transformations on the biological activity of this class of metabolites. The promising compounds identified from Theonella spp. possess pronounced biological activity on nuclear receptors or cytotoxicity and result in promising candidates for extended preclinical evaluations. The identification of naturally occurring and semisynthetic marine bioactive sterols reaffirms the utility of examining natural product libraries for the discovery of new therapeutical approach to human diseases. Full article

(This article belongs to the Special Issue Characterization of Structure-Activity Relationships in Marine Natural Products)

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17 pages, 370 KiB

Open AccessReview

Antimicrobial Peptides from Photosynthetic Marine Organisms with Potential Application in Aquaculture

by José María García-Beltrán, Marta Arizcun and Elena Chaves-Pozo

Mar. Drugs 2023, 21(5), 290; https://doi.org/10.3390/md21050290 - 08 May 2023

Cited by 4 | Viewed by 1767

Abstract

Aquaculture production is at a record level and is estimated to increase in the coming years. However, this production can be negatively affected by infectious diseases produced by viruses, bacteria, and parasites, causing fish mortality and economic losses. Antimicrobial peptides (AMPs) are small [...] Read more.

Aquaculture production is at a record level and is estimated to increase in the coming years. However, this production can be negatively affected by infectious diseases produced by viruses, bacteria, and parasites, causing fish mortality and economic losses. Antimicrobial peptides (AMPs) are small peptides that may be promising candidates to replace antibiotics because they are the first line of defense in animals against a wide variety of pathogens and have no negative effects; they also show additional activities such as antioxidant or immunoregulatory functions, which makes them powerful alternatives for use in aquaculture. Moreover, AMPs are highly available in natural sources and have already been used in the livestock farming and food industries. Photosynthetic marine organisms can survive under all kinds of environmental conditions and under extremely competitive environments thanks to their flexible metabolism. For this reason, these organisms represent a powerful source of bioactive molecules as nutraceuticals and pharmaceuticals, including AMPs. Therefore, in this study we reviewed the present knowledge about AMPs from photosynthetic marine organism sources and analyzed whether they could be suitable for use in aquaculture. Full article

(This article belongs to the Special Issue Pharmaceutical Potential of Marine Microorganisms)

18 pages, 109634 KiB

Open AccessArticle

Anti-Leukemia Activity of Polysaccharide from Sargassum fusiforme via the PI3K/AKT/BAD Pathway In Vivo and In Vitro

by Haofei Du, Xudong Jin, Sizhou Jin, Donglei Zhang, Qiande Chen, Xuanan Jin, Caisheng Wang, Guoying Qian and Haomiao Ding

Mar. Drugs 2023, 21(5), 289; https://doi.org/10.3390/md21050289 - 08 May 2023

Cited by 3 | Viewed by 1501

Abstract

Studies have shown that Sargassum fusiforme and its extracts are effective herbal treatments for leukemia. We previously found that a polysaccharide from Sargassum fusiforme, SFP 2205, stimulated apoptosis in human erythroleukemia (HEL) cells. However, the structural characterization and antitumoral mechanisms of SFP [...] Read more.

Studies have shown that Sargassum fusiforme and its extracts are effective herbal treatments for leukemia. We previously found that a polysaccharide from Sargassum fusiforme, SFP 2205, stimulated apoptosis in human erythroleukemia (HEL) cells. However, the structural characterization and antitumoral mechanisms of SFP 2205 remain uncertain. Here, we studied the structural characteristics and anticancer mechanisms of SFP 2205 in HEL cells and a xenograft mouse model. The results demonstrated that SFP 2205, with a molecular weight of 41.85 kDa, consists of mannose, rhamnose, galactose, xylose, glucose, and fucose with monosaccharides composition of 14.2%, 9.4%, 11.8%, 13.7%, 11.0%, and 38.3%, respectively. On animal assays, SFP 2205 significantly inhibited growth of HEL tumor xenografts with no discernible toxicity to normal tissues. Western blotting showed that SFP 2205 therapy improved Bad, Caspase-9, and Caspase-3 protein expression, and ultimately induced HEL tumor apoptosis, indicating mitochondrial pathway involvement. Furthermore, SFP 2205 blocked the PI3K/AKT signaling pathway and 740 Y-P, an activator of the PI3K/AKT pathway, rescued the effects of SFP 2205 on HEL cell proliferation and apoptosis. Overall, SFP 2205 may be a potential functional food additive or adjuvant for preventing or treating leukemia. Full article

(This article belongs to the Topic Advances on the Extraction, Functionalities and Applications of Polysaccharides)

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21 pages, 5287 KiB

Open AccessArticle

Structural Manipulations of Marine Natural Products Inspire a New Library of 3-Amino-1,2,4-Triazine PDK Inhibitors Endowed with Antitumor Activity in Pancreatic Ductal Adenocarcinoma

by Daniela Carbone, Michele De Franco, Camilla Pecoraro, Davide Bassani, Matteo Pavan, Stella Cascioferro, Barbara Parrino, Girolamo Cirrincione, Stefano Dall’Acqua, Stefania Sut, Stefano Moro, Valentina Gandin and Patrizia Diana

Mar. Drugs 2023, 21(5), 288; https://doi.org/10.3390/md21050288 - 04 May 2023

Cited by 5 | Viewed by 2083

Abstract

Pancreatic ductal adenocarcinoma (PDAC) is one of the main aggressive types of cancer, characterized by late prognosis and drug resistance. Among the main factors sustaining PDAC progression, the alteration of cell metabolism has emerged to have a key role in PDAC cell proliferation, [...] Read more.

Pancreatic ductal adenocarcinoma (PDAC) is one of the main aggressive types of cancer, characterized by late prognosis and drug resistance. Among the main factors sustaining PDAC progression, the alteration of cell metabolism has emerged to have a key role in PDAC cell proliferation, invasion, and resistance to standard chemotherapeutic agents. Taking into account all these factors and the urgency in evaluating novel options to treat PDAC, in the present work we reported the synthesis of a new series of indolyl-7-azaindolyl triazine compounds inspired by marine bis-indolyl alkaloids. We first assessed the ability of the new triazine compounds to inhibit the enzymatic activity of pyruvate dehydrogenase kinases (PDKs). The results showed that most of derivatives totally inhibit PDK1 and PDK4. Molecular docking analysis was executed to predict the possible binding mode of these derivatives using ligand-based homology modeling technique. Evaluation of the capability of new triazines to inhibit the cell growth in 2D and 3D KRAS-wild-type (BxPC-3) and KRAS-mutant (PSN-1) PDAC cell line, was carried out. The results showed the capacity of the new derivatives to reduce cell growth with a major selectivity against KRAS-mutant PDAC PSN-1 on both cell models. These data demonstrated that the new triazine derivatives target PDK1 enzymatic activity and exhibit cytotoxic effects on 2D and 3D PDAC cell models, thus encouraging further structure manipulation for analogs development against PDAC. Full article

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Mar. Drugs, Volume 21, Issue 5 (May 2023) – 59 articles

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