Marine Drugs

16 pages, 3123 KiB

Open AccessArticle

Heterologous Expression and Characterization of a pH-Stable Chitinase from Micromonospora aurantiaca with a Potential Application in Chitin Degradation

by Han-Zhong Guo, Dou Wang, Hui-Ting Yang, Yu-Le Wu, Yong-Cheng Li, Guang-Hua **a and Xue-Ying Zhang

Mar. Drugs 2024, 22(6), 287; https://doi.org/10.3390/md22060287 - 20 Jun 2024

Viewed by 385

Abstract

To promote the bioconversion of marine chitin waste into value-added products, we expressed a novel pH-stable Micromonospora aurantiaca-derived chitinase, MaChi1, in Escherichia coli and subsequently purified, characterized, and evaluated it for its chitin-converting capacity. Our results indicated that MaChi1 is [...] Read more.

To promote the bioconversion of marine chitin waste into value-added products, we expressed a novel pH-stable Micromonospora aurantiaca-derived chitinase, MaChi1, in Escherichia coli and subsequently purified, characterized, and evaluated it for its chitin-converting capacity. Our results indicated that MaChi1 is of the glycoside hydrolase (GH) family 18 with a molecular weight of approximately 57 kDa, consisting of a GH18 catalytic domain and a cellulose-binding domain. We recorded its optimal activity at pH 5.0 and 55 °C. It exhibited excellent stability in a wide pH range of 3.0–10.0. Mg²⁺ (5 mM), and dithiothreitol (10 mM) significantly promoted MaChi1 activity. MaChi1 exhibited broad substrate specificity and hydrolyzed chitin, chitosan, cellulose, soluble starch, and N-acetyl chitooligosaccharides with polymerization degrees ranging from three to six. Moreover, MaChi1 exhibited an endo-type cleavage pattern, and it could efficiently convert colloidal chitin into N-acetyl-D-glucosamine (GlcNAc) and (GlcNAc)₂ with yields of 227.2 and 505.9 mg/g chitin, respectively. Its high chitin-degrading capacity and exceptional pH tolerance makes it a promising tool with potential applications in chitin waste treatment and bioactive oligosaccharide production. Full article

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

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16 pages, 6660 KiB

Open AccessArticle

A Tripeptide (Ser-Arg-Pro, SRP) from Sipunculus nudus L. Improves Cadmium-Induced Acute Kidney Injury by Targeting the MAPK, Inflammatory, and Apoptosis Pathways in Mice

by Yanmei Pan, Zhilan Peng, Zhijia Fang, Lukman Iddrisu, Lijun Sun, Qi Deng and Ravi Gooneratne

Mar. Drugs 2024, 22(6), 286; https://doi.org/10.3390/md22060286 - 20 Jun 2024

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Abstract

Cadmium (Cd) is a toxic heavy metal that causes nephrosis, including acute kidney injury. To prevent and treat acute kidney injury (AKI) following Cd exposure, a tripeptide, Ser-Arg-Pro (SRP), from Sipunculus nudus L. was employed, and its potential efficacy in AKI was assessed. [...] Read more.

Cadmium (Cd) is a toxic heavy metal that causes nephrosis, including acute kidney injury. To prevent and treat acute kidney injury (AKI) following Cd exposure, a tripeptide, Ser-Arg-Pro (SRP), from Sipunculus nudus L. was employed, and its potential efficacy in AKI was assessed. Oral administration of SRP significantly alleviated Cd-induced kidney damage, leading to improved renal function and the attenuation of structural abnormalities. A network pharmacology analysis revealed the potential of SRP in renal protection by targeting various pathways, including mitogen-activated protein kinase (MAPK) signaling, inflammatory response, and apoptosis pathways. Mechanistic studies indicated that SRP achieves renal protection by inhibiting the activation of MAPK pathways (phosphorylation of p38, p56, ERK, and JNK) in the oxidative stress cascade, suppressing inflammatory responses (iNOS, Arg1, Cox2, TNF-α, IL-1β, and IL-6), and restoring altered apoptosis factors (caspase-9, caspase-3, Bax, and Bcl-2). Hence, SRP has the potential to be used as a therapeutic agent for the treatment of Cd-induced nephrotoxicity. Full article

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

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19 pages, 9456 KiB

Open AccessArticle

Reversed-Phase Medium-Pressure Liquid Chromatography Purification of Omega-3 Fatty Acid Ethyl Esters Using AQ-C18

by Mingxin Sang, Nan Pan, **gna Wu, **aoting Chen, Shuilin Cai, Huan Fang, Meitian **ao, **aoming Jiang and Zhiyu Liu

Mar. Drugs 2024, 22(6), 285; https://doi.org/10.3390/md22060285 - 19 Jun 2024

Viewed by 994

Abstract

Omega-3 fatty acids are in high demand due to their efficacy in treating hypertriglyceridemia and preventing cardiovascular diseases. However, the growth of the industry is hampered by low purity and insufficient productivity. This study aims to develop an efficient RP-MPLC purification method for [...] Read more.

Omega-3 fatty acids are in high demand due to their efficacy in treating hypertriglyceridemia and preventing cardiovascular diseases. However, the growth of the industry is hampered by low purity and insufficient productivity. This study aims to develop an efficient RP-MPLC purification method for omega-3 fatty acid ethyl esters with high purity and capacity. The results indicate that the AQ-C18 featuring polar end-capped silanol groups outperformed C18 and others in retention time and impurity separation. By injecting pure fish oil esters with a volume equivalent to a 1.25% bed volume on an AQ-C18 MPLC column using a binary isocratic methanol–water (90:10, v:v) mobile phase at 30 mL/min, optimal omega-3 fatty acid ethyl esters were obtained, with the notable purity of 90.34% and a recovery rate of 74.30%. The total content of EPA and DHA produced increased from 67.91% to 85.27%, meeting the acceptance criteria of no less than 84% set by the 2020 edition of the Pharmacopoeia of the People’s Republic of China. In contrast, RP-MPLC significantly enhanced the production efficiency per unit output compared to RP-HPLC. This study demonstrates a pioneering approach to producing omega-3 fatty acid ethyl esters with high purity and of greater quantity using AQ-C18 RP-MPLC, showing this method’s significant potential for use in industrial-scale manufacturing. Full article

(This article belongs to the Special Issue Fatty Acids from Marine Organisms, 2nd Edition)

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19 pages, 2677 KiB

Open AccessArticle

Optimizing the Extraction of Bioactive Compounds from Porphyra linearis (Rhodophyta): Evaluating Alkaline and Enzymatic Hydrolysis for Nutraceutical Applications

by Débora Tomazi Pereira, Paz García-García, Nathalie Korbee, Julia Vega, Francisco J. Señoráns and Félix L. Figueroa

Mar. Drugs 2024, 22(6), 284; https://doi.org/10.3390/md22060284 - 18 Jun 2024

Viewed by 1007

Abstract

Porphyra sensu lato is one of the most economically significant and widely cultured and consumed algae in the world. Porphyra species present excellent nutraceutic properties due to their bioactive compounds (BACs). This research aimed to find the most efficient aqueous extraction method for BACs [...] Read more.

Porphyra sensu lato is one of the most economically significant and widely cultured and consumed algae in the world. Porphyra species present excellent nutraceutic properties due to their bioactive compounds (BACs). This research aimed to find the most efficient aqueous extraction method for BACs by examining alkaline and enzymatic hydrolysis. Alkaline hydrolysis with 2.5% sodium carbonate (SC) and at 80 °C proved optimal for extracting all BACs (phycobiliproteins, soluble proteins, polyphenols, and carbohydrates) except mycosporine-like amino acids (MAAs), which were best extracted with water only, and at 80 °C. Enzymatic hydrolysis, particularly with the ‘Miura’ enzymatic cocktail (cellulase, xylanase, glycoside hydrolase, and β-glucanase), showed superior results in extracting phycoerythrin (PE), phycocyanin (PC), soluble proteins, and carbohydrates, with increases of approximately 195%, 510%, 890%, and 65%, respectively, compared to the best alkaline hydrolysis extraction (2.5% SC and 80 °C). Phenolic content analysis showed no significant difference between the ‘Miura’ cocktail and 2.5% SC treatments. Antioxidant activity was higher in samples from alkaline hydrolysis, while extraction of MAAs showed no significant difference between water-only and ‘Miura’ treatments. The study concludes that enzymatic hydrolysis improves the efficiency of BACs extraction in P. linearis, highlighting its potential for the nutraceutical industry, and especially with respect to MAAs for topical and oral UV-photoprotectors. Full article

(This article belongs to the Special Issue High-Value Algae Products)

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16 pages, 4839 KiB

Open AccessArticle

Isaridin E Protects against Sepsis by Inhibiting Von Willebrand Factor-Induced Endothelial Hyperpermeability and Platelet–Endothelium Interaction

by Yao-Sheng Liu, Wen-Liang Chen, Yu-Wei Zeng, Zhi-Hong Li, Hao-Lin Zheng, Ni Pan, Li-Yan Zhao, Shu Wang, Sen-Hua Chen, Ming-Hua Jiang, Chen-Chen **, Yu-Chen Mi, Zhao-Hui Cai, **n-Zhe Fang, Yong-Jun Liu, Lan Liu and Guan-Lei Wang

Mar. Drugs 2024, 22(6), 283; https://doi.org/10.3390/md22060283 - 16 Jun 2024

Viewed by 712

Abstract

Endothelial hyperpermeability is pivotal in sepsis-associated multi-organ dysfunction. Increased von Willebrand factor (vWF) plasma levels, stemming from activated platelets and endothelium injury during sepsis, can bind to integrin αvβ3, exacerbating endothelial permeability. Hence, targeting this pathway presents a potential therapeutic avenue for sepsis. [...] Read more.

Endothelial hyperpermeability is pivotal in sepsis-associated multi-organ dysfunction. Increased von Willebrand factor (vWF) plasma levels, stemming from activated platelets and endothelium injury during sepsis, can bind to integrin αvβ3, exacerbating endothelial permeability. Hence, targeting this pathway presents a potential therapeutic avenue for sepsis. Recently, we identified isaridin E (ISE), a marine-derived fungal cyclohexadepsipeptide, as a promising antiplatelet and antithrombotic agent with a low bleeding risk. ISE’s influence on septic mortality and sepsis-induced lung injury in a mouse model of sepsis, induced by caecal ligation and puncture, is investigated in this study. ISE dose-dependently improved survival rates, mitigating lung injury, thrombocytopenia, pulmonary endothelial permeability, and vascular inflammation in the mouse model. ISE markedly curtailed vWF release from activated platelets in septic mice by suppressing vesicle-associated membrane protein 8 and soluble N-ethylmaleide-sensitive factor attachment protein 23 overexpression. Moreover, ISE inhibited healthy human platelet adhesion to cultured lipopolysaccharide (LPS)-stimulated human umbilical vein endothelial cells (HUVECs), thereby significantly decreasing vWF secretion and endothelial hyperpermeability. Using cilengitide, a selective integrin αvβ3 inhibitor, it was found that ISE can improve endothelial hyperpermeability by inhibiting vWF binding to αvβ3. Activation of the integrin αvβ3-FAK/Src pathway likely underlies vWF-induced endothelial dysfunction in sepsis. In conclusion, ISE protects against sepsis by inhibiting endothelial hyperpermeability and platelet-endothelium interactions. Full article

(This article belongs to the Special Issue Pharmacological Potential of Marine Natural Products)

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10 pages, 1078 KiB

Open AccessArticle

New Cyclic Pentapeptides from the Mangrove-Derived Aspergillus fumigatus GXIMD 03099

by Yu Wang, Guang** Cao, Yuman Gan, **ao Lin, **angxi Yi, Longyan Zhao, Yonghong Liu, Chenghai Gao and Meng Bai

Mar. Drugs 2024, 22(6), 282; https://doi.org/10.3390/md22060282 - 16 Jun 2024

Viewed by 575

Abstract

Four new cyclic pentapeptides, avellanins D–G (1–4), together with four known compounds (5–8), were isolated from a mangrove-derived Aspergillus fumigatus GXIMD 03099 fungus from Acanthus ilicifolius L. Their structures were elucidated by analysis of HRESIMS, [...] Read more.

Four new cyclic pentapeptides, avellanins D–G (1–4), together with four known compounds (5–8), were isolated from a mangrove-derived Aspergillus fumigatus GXIMD 03099 fungus from Acanthus ilicifolius L. Their structures were elucidated by analysis of HRESIMS, NMR, and ESI-MS/MS data. Their absolute configurations were determined by X-ray diffraction analysis and Marfey’s method. Compounds 1–8 were screened for insecticidal and antibacterial activities. Compound 2 showed insecticidal activity against newly hatched larvae of Culex quinquefasciatus with an LC₅₀ value of 86.6 µM; compound 4 had weak activity against Vibrio harveyi with an MIC value of 5.85 µM. Full article

(This article belongs to the Special Issue Bioactive Secondary Metabolites of Marine Fungi 2.0)

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21 pages, 4077 KiB

Open AccessArticle

Innovative Alkanediol-Based Eutectic Solvents for Extracting/Pre-Formulating Dermatologically Valuable Free Fatty Acids from Spirulina and Porphyridium Cakes

by Laura Wils, Mervé Yagmur, Nicolas Bellin, Myriam Phelippe, Alia Chevalley, Charles Bodet and Leslie Boudesocque-Delaye

Mar. Drugs 2024, 22(6), 281; https://doi.org/10.3390/md22060281 - 15 Jun 2024

Viewed by 746

Abstract

The growing demand for phycobiliproteins from microalgae generates a significant volume of by-products, such as extraction cakes. These cakes are enriched with products of interest for the cosmetics market, namely free fatty acids, particularly polyunsaturated (PUFA). In this work, two cakes, one of [...] Read more.

The growing demand for phycobiliproteins from microalgae generates a significant volume of by-products, such as extraction cakes. These cakes are enriched with products of interest for the cosmetics market, namely free fatty acids, particularly polyunsaturated (PUFA). In this work, two cakes, one of spirulina and one of Porphyridium cruentum, were valorized using innovative natural hydrophobic deep eutectic solvents (NaDES) based on alkanediols. The most promising NaDES, as determined by physicochemical properties and screening, are mixtures of alkanediols and fatty acids. These include the mixtures of 1,3-propanediol and octanoic acid (1:5, mol/mol) and 1,3-propanediol and octanoic and decanoic acid (1:3:1, mol/mol). Two extractive processes were implemented: ultrasound-assisted extraction and an innovative mechanical process involving dual asymmetric centrifugation. The second process resulted in the production of extracts significantly enriched in PUFA, ranging from 65 to 220 mg/g dry matter with the two cakes. The extracts and NaDES demonstrated good safety with respect to epidermal keratinocyte viability (>80% at 200 µg/mL). The study of their impact on commensal and pathogenic cutaneous bacteria demonstrated significant effects on the viability of Staphylococcus aureus and Staphylococcus epidermidis (>50% decrease at 200 µg/mL) while preserving Corynebacterium xerosis and Cutibacterium acnes. These results highlight the potential of valorizing these co-products using alkanediol-based NaDES, in a strategy combining an active vector (NaDES) and a growth regulator extract, for the management of cutaneous dysbiosis involving staphylococci. Full article

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23 pages, 3253 KiB

Open AccessArticle

Improvement of Alginate Extraction from Brown Seaweed (Laminaria digitata L.) and Valorization of Its Remaining Ethanolic Fraction

by Ivana M. Savić Gajić, Ivan M. Savić, Aleksandra M. Ivanovska, Jovana D. Vunduk, Ivana S. Mihalj and Zorica B. Svirčev

Mar. Drugs 2024, 22(6), 280; https://doi.org/10.3390/md22060280 - 15 Jun 2024

Viewed by 748

Abstract

This study aimed to improve the conventional procedure of alginate isolation from the brown seaweed (Laminaria digitata L.) biomass and investigate the possibility of further valorization of the ethanolic fraction representing the byproduct after the degreasing and depigmentation of biomass. The acid [...] Read more.

This study aimed to improve the conventional procedure of alginate isolation from the brown seaweed (Laminaria digitata L.) biomass and investigate the possibility of further valorization of the ethanolic fraction representing the byproduct after the degreasing and depigmentation of biomass. The acid treatment of biomass supported by ultrasound was modeled and optimized regarding the alginate yield using a response surface methodology based on the Box–Behnken design. A treatment time of 30 min, a liquid-to-solid ratio of 30 mL/g, and a treatment temperature of 47 °C were proposed as optimal conditions under which the alginate yield related to the mass of dry biomass was 30.9%. The use of ultrasonic radiation significantly reduced the time required for the acid treatment of biomass by about 4 to 24 times compared to other available conventional procedures. The isolated alginate had an M/G ratio of 1.08, which indicates a greater presence of M-blocks in its structure and the possibility of forming a soft and elastic hydrogel with its use. The chemical composition of the ethanolic fraction including total antioxidant content (293 mg gallic acid equivalent/g dry weight), total flavonoid content (14.9 mg rutin equivalent/g dry weight), contents of macroelements (the highest content of sodium, 106.59 mg/g dry weight), and microelement content (the highest content of boron, 198.84 mg/g dry weight) was determined, and the identification of bioactive compounds was carried out. The results of ultra high-performance liquid chromatography–electrospray ionization–tandem mass spectrometry analysis confirmed the presence of 48 compounds, of which 41 compounds were identified as sugar alcohol, phenolic compounds, and lipids. According to the 2,2-diphenyl-1-picrylhydrazyl assay, the radical scavenging activity of the ethanolic fraction (the half-maximal inhibitory concentration of 42.84 ± 0.81 μg/mL) indicated its strong activity, which was almost the same as in the case of the positive control, synthetic antioxidant butylhydroxytoluene (the half-maximal inhibitory concentration of 36.61 ± 0.79 μg/mL). Gram-positive bacteria (Staphylococcus aureus, Enterococcus faecalis, and Bacillus cereus) were more sensitive to the ethanolic fraction compared to Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, and Shigella sonnei). The obtained results indicated the possibility of the further use of the ethanolic fraction as a fertilizer for plant growth in different species and antifouling agents, applicable in aquaculture. 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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17 pages, 3108 KiB

Open AccessArticle

Purification and Screening of the Antialgal Activity of Seaweed Extracts and a New Glycolipid Derivative against Two Ichthyotoxic Red Tide Microalgae Amphidinium carterae and Karenia mikimotoi

by Yingying Sun, Hui Li, **ao Ma, Mengxuan Pu, Yuqi Zhang, Zhuohan Dong, Peicong He and Shiyan Zheng

Mar. Drugs 2024, 22(6), 279; https://doi.org/10.3390/md22060279 - 14 Jun 2024

Viewed by 389

Abstract

Ichthyotoxic red tide is a problem that the world is facing and needs to solve. The use of antialgal compounds from marine macroalgae to suppress ichthyotoxic red tide is considered a promising biological control method. Antialgal substances were screened and isolated from Bangia [...] Read more.

Ichthyotoxic red tide is a problem that the world is facing and needs to solve. The use of antialgal compounds from marine macroalgae to suppress ichthyotoxic red tide is considered a promising biological control method. Antialgal substances were screened and isolated from Bangia fusco-purpurea, Gelidium amansii, Gloiopeltis furcate, Hizikia fusifarme, Laminaria japonica, Palmaria palmata, and Sargassum sp. to obtain new materials for the development of algaecides against ichthyotoxic red tide microalgae using bioactivity-guided isolation methods. The fractions of seven macroalgae exhibited selective inhibitory activities against Amphidinium carterae and Karenia mikimotoi, of which the ethyl acetate fractions had the strongest and broadest antialgal activities for the two tested red tide microalgae. Their inhibitory effects on A. carterae and K. mikimotoi were even stronger than that of potassium dichromate, such as ethyl acetate fractions of B. purpurea, H. fusifarme, and Sargassum sp. Thin-layer chromatography and ultraviolet spectroscopy were further carried out to screen the ethyl acetate fraction of Sargassum sp. Finally, a new glycolipid derivative, 2-O-eicosanoyl-3-O-(6-amino-6-deoxy)-β-D-glucopyranosyl-glycerol, was isolated and identified from Sargassum sp., and it was isolated for the first time from marine macroalgae. The significant antialgal effects of 2-O-eicosanoyl-3-O-(6-amino-6-deoxy)-β-D-glucopyranosyl-glycerol on A. carterae and K. mikimotoi were determined. Full article

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

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18 pages, 7033 KiB

Open AccessArticle

Dicerandrol C Suppresses Proliferation and Induces Apoptosis of HepG2 and Hela Cancer Cells by Inhibiting Wnt/β-Catenin Signaling Pathway

by Dongdong Zhou, Dandan Chen, **gwan Wu, Ting Feng, **huai Liu and **g Xu

Mar. Drugs 2024, 22(6), 278; https://doi.org/10.3390/md22060278 - 14 Jun 2024

Viewed by 517

Abstract

Overwhelming evidence points to an aberrant Wnt/β-catenin signaling as a critical factor in hepatocellular carcinoma (HCC) and cervical cancer (CC) pathogenesis. Dicerandrol C (DD-9), a dimeric tetrahydroxanthenone isolated from the endophytic fungus Phomopsis asparagi DHS-48 obtained from mangrove plant Rhizophora mangle via chemical [...] Read more.

Overwhelming evidence points to an aberrant Wnt/β-catenin signaling as a critical factor in hepatocellular carcinoma (HCC) and cervical cancer (CC) pathogenesis. Dicerandrol C (DD-9), a dimeric tetrahydroxanthenone isolated from the endophytic fungus Phomopsis asparagi DHS-48 obtained from mangrove plant Rhizophora mangle via chemical epigenetic manipulation of the culture, has demonstrated effective anti-tumor properties, with an obscure action mechanism. The objective of the current study was to explore the efficacy of DD-9 on HepG2 and HeLa cancer cells and its functional mechanism amid the Wnt/β catenin signaling cascade. Isolation of DD-9 was carried out using various column chromatographic methods, and its structure was elucidated with 1D NMR. The cytotoxicity of DD-9 on HepG2 and HeLa cells was observed with respect to the proliferation, clonality, migration, invasion, apoptosis, cell cycle, and Wnt/β-catenin signaling cascade. We found that DD-9 treatment significantly reduced tumor cell proliferation in dose- and time-dependent manners in HepG2 and HeLa cells. The subsequent experiments in vitro implied that DD-63 could significantly suppress the tumor clonality, metastases, and induced apoptosis, and that it arrested the cell cycle at the G₀/G₁ phase of HepG2 and HeLa cells. Dual luciferase assay, Western blot, and immunofluorescence assay showed that DD-9 could dose-dependently attenuate the Wnt/β-catenin signaling by inhibiting β-catenin transcriptional activity and abrogating β-catenin translocated to the nucleus; down-regulating the transcription level of β-catenin-stimulated Wnt target gene and the expression of related proteins including p-GSK3-β, β-catenin, LEF1, Axin1, c-Myc, and CyclinD1; and up-regulating GSK3-β expression, which indicates that DD-9 stabilized the β-catenin degradation complex, thereby inducing β-catenin degradation and inactivation of the Wnt/β-catenin pathway. The possible interaction between DD-9 and β-catenin and GSK3-β protein was further confirmed by molecular docking studies. Collectively, DD-9 may suppress proliferation and induce apoptosis of liver and cervical cancer cells, possibly at least in part via GSK3-β-mediated crosstalk with the Wnt/β-catenin signaling axis, providing insights into the mechanism for the potency of DD-9 on hepatocellular and cervical cancer. Full article

(This article belongs to the Special Issue Marine Bioactive Compound Discovery through OSMAC Approach)

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9 pages, 2233 KiB

Open AccessCommunication

New Meroterpenoids and α-Pyrone Derivatives Isolated from the Mangrove Endophytic Fungal Strain Aspergillus sp. GXNU-Y85

by Chungu Wang, Fanfan Wang, **fang Tao, Yuanling Shao, Qing Li, Minmin Gu, Zhixin Liao and Feng Qin

Mar. Drugs 2024, 22(6), 277; https://doi.org/10.3390/md22060277 - 13 Jun 2024

Viewed by 522

Abstract

Two new meroterpenoids, aspergienynes O and P (1 and 2), one new natural compound, aspergienyne Q (3), and a new α-pyrone derivative named 3-(4-methoxy-2-oxo-2H-pyran-6-yl)butanoic acid (4) were isolated from the mangrove endophytic fungal strain Aspergillus sp. GXNU-Y85, [...] Read more.

Two new meroterpenoids, aspergienynes O and P (1 and 2), one new natural compound, aspergienyne Q (3), and a new α-pyrone derivative named 3-(4-methoxy-2-oxo-2H-pyran-6-yl)butanoic acid (4) were isolated from the mangrove endophytic fungal strain Aspergillus sp. GXNU-Y85, along with five known compounds (5–9). The absolute configurations of those new isolates were confirmed through extensive analysis using spectroscopic data (HRESIMS, NMR, and ECD). The pharmacological study of the anti-proliferation activity indicated that isolates 5 and 9 displayed moderate inhibitory effects against HeLa and A549 cells, with the IC₅₀ values ranging from 16.6 to 45.4 μM. Full article

(This article belongs to the Special Issue Bio-Active Products from Mangrove Ecosystems 2.0)

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17 pages, 3843 KiB

Open AccessArticle

Characterization and Biosynthetic Regulation of Isoflavone Genistein in Deep-Sea Actinomycetes Microbacterium sp. B1075

by **n Li, Yukun Cui, Weichao Wu, Zhizhen Zhang, Jiasong Fang, ** Yu and Junwei Cao

Mar. Drugs 2024, 22(6), 276; https://doi.org/10.3390/md22060276 - 13 Jun 2024

Viewed by 549

Abstract

Deep-sea environments, as relatively unexplored extremes within the Earth’s biosphere, exhibit notable distinctions from terrestrial habitats. To thrive in these extreme conditions, deep-sea actinomycetes have evolved unique biochemical metabolisms and physiological capabilities to ensure their survival in this niche. In this study, five [...] Read more.

Deep-sea environments, as relatively unexplored extremes within the Earth’s biosphere, exhibit notable distinctions from terrestrial habitats. To thrive in these extreme conditions, deep-sea actinomycetes have evolved unique biochemical metabolisms and physiological capabilities to ensure their survival in this niche. In this study, five actinomycetes strains were isolated and identified from the Mariana Trench via the culture-dependent method and 16S rRNA sequencing approach. The antimicrobial activity of Microbacterium sp. B1075 was found to be the most potent, and therefore, it was selected as the target strain. Molecular networking analysis via the Global Natural Products Social Molecular Networking (GNPS) platform identified 25 flavonoid compounds as flavonoid secondary metabolites. Among these, genistein was purified and identified as a bioactive compound with significant antibacterial activity. The complete synthesis pathway for genistein was proposed within strain B1075 based on whole-genome sequencing data, with the key gene being CHS (encoding chalcone synthase). The expression of the gene CHS was significantly regulated by high hydrostatic pressure, with a consequent impact on the production of flavonoid compounds in strain B1075, revealing the relationship between actinomycetes’ synthesis of flavonoid-like secondary metabolites and their adaptation to high-pressure environments at the molecular level. These results not only expand our understanding of deep-sea microorganisms but also hold promise for providing valuable insights into the development of novel pharmaceuticals in the field of biopharmaceuticals. Full article

(This article belongs to the Special Issue Bioactive Compounds from the Deep-Sea-Derived Microorganisms 2.0)

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13 pages, 6278 KiB

Open AccessArticle

Avellanin A Has an Antiproliferative Effect on TP-Induced RWPE-1 Cells via the PI3K-Akt Signalling Pathway

by Chang Xu, Guang** Cao, Hong Zhang, Meng Bai, **angxi Yi and **njian Qu

Mar. Drugs 2024, 22(6), 275; https://doi.org/10.3390/md22060275 - 13 Jun 2024

Viewed by 508

Abstract

Cyclic pentapeptide compounds have garnered much attention as a drug discovery resource. This study focused on the characterization and anti-benign prostatic hyperplasia (BPH) properties of avellanin A from Aspergillus fumigatus fungus in marine sediment samples collected in the Beibu Gulf of Guangxi Province [...] Read more.

Cyclic pentapeptide compounds have garnered much attention as a drug discovery resource. This study focused on the characterization and anti-benign prostatic hyperplasia (BPH) properties of avellanin A from Aspergillus fumigatus fungus in marine sediment samples collected in the Beibu Gulf of Guangxi Province in China. The antiproliferative effect and molecular mechanism of avellanin A were explored in testosterone propionate (TP)-induced RWPE-1 cells. The transcriptome results showed that avellanin A significantly blocked the ECM–receptor interaction and suppressed the downstream PI3K-Akt signalling pathway. Molecular docking revealed that avellanin A has a good affinity for the cathepsin L protein, which is involved in the terminal degradation of extracellular matrix components. Subsequently, qRT-PCR analysis revealed that the expression of the genes COL1A1, COL1A2, COL5A2, COL6A3, MMP2, MMP9, ITGA2, and ITGB3 was significantly downregulated after avellanin A intervention. The Western blot results also confirmed that it not only reduced ITGB3 and FAK/p-FAK protein expression but also inhibited PI3K/p-PI3K and Akt/p-Akt protein expression in the PI3K-Akt signalling pathway. Furthermore, avellanin A downregulated Cyclin D1 protein expression and upregulated Bax, p21^WAF1/Cip1, and p53 proapoptotic protein expression in TP-induced RWPE-1 cells, leading to cell cycle arrest and inhibition of cell proliferation. The results of this study support the use of avellanin A as a potential new drug for the treatment of BPH. Full article

(This article belongs to the Special Issue Pharmacological Potential of Marine Natural Products)

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10 pages, 2011 KiB

Open AccessCommunication

Cytotoxic Pentaketide-Sesquiterpenes from the Marine-Derived Fungus Talaromyces variabilis M22734

by Lingzhi Tang, **mei **a, Zhongwei Chen, **aohui Wu, Guangyu Li, Qiliang Lai, Zongze Shao, Weiyi Wang and Xuan Hong

Mar. Drugs 2024, 22(6), 274; https://doi.org/10.3390/md22060274 - 13 Jun 2024

Viewed by 610

Abstract

Talaromyces, a filamentous fungus widely distributed across terrestrial and marine environments, can produce a diverse array of natural products, including alkaloids, polyketones, and polyketide-terpenoids. Among these, chrodrimanins represented a typical class of natural products. In this study, we isolated three previously undescribed [...] Read more.

Talaromyces, a filamentous fungus widely distributed across terrestrial and marine environments, can produce a diverse array of natural products, including alkaloids, polyketones, and polyketide-terpenoids. Among these, chrodrimanins represented a typical class of natural products. In this study, we isolated three previously undescribed pentaketide-sesquiterpenes, 8,9-epi-chrodrimanins (1–3), along with eight known compounds (4–11). The structures of compounds 1–3 were elucidated using nuclear magnetic resonance (NMR) and mass spectrometry (MS), while their absolute configurations were determined through X-ray crystallography and electronic circular dichroism (ECD) computations. The biosynthetic pathways of compounds 1–3 initiate with 6-hydroxymellein and involve multiple stages of isoprenylation, cyclization, oxidation, and acetylation. We selected four strains of gastrointestinal cancer cells for activity evaluation. We found that compound 3 selectively inhibited MKN-45, whereas compounds 1 and 2 exhibited no significant inhibitory activity against the four cell lines. These findings suggested that 8,9-epi-chrodrimanins could serve as scaffold compounds for further structural modifications, potentially leading to the development of targeted therapies for gastric cancer. Full article

(This article belongs to the Special Issue Marine-Derived Terpenes: Chemistry, Synthesis and Their Therapeutic Potential)

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26 pages, 1684 KiB

Open AccessArticle

Exploring Bioactive Components and Assessing Antioxidant and Antibacterial Activities in Five Seaweed Extracts from the Northeastern Coast of Algeria

by Nawal Bouzenad, Nesrine Ammouchi, Nadjla Chaib, Mohammed Messaoudi, Walid Bousabaa, Chawki Bensouici, Barbara Sawicka, Maria Atanassova, Sheikh F. Ahmad and Wafa Zahnit

Mar. Drugs 2024, 22(6), 273; https://doi.org/10.3390/md22060273 - 12 Jun 2024

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Abstract

The main goal of this study was to assess the bioactive and polysaccharide compositions, along with the antioxidant and antibacterial potentials, of five seaweeds collected from the northeastern coast of Algeria. Through Fourier transform infrared spectroscopy analysis and X-ray fluorescence spectroscopy, the study [...] Read more.

The main goal of this study was to assess the bioactive and polysaccharide compositions, along with the antioxidant and antibacterial potentials, of five seaweeds collected from the northeastern coast of Algeria. Through Fourier transform infrared spectroscopy analysis and X-ray fluorescence spectroscopy, the study investigated the elemental composition of these seaweeds and their chemical structure. In addition, this study compared and identified the biochemical makeup of the collected seaweed by using cutting-edge methods like tandem mass spectrometry and ultra-high-performance liquid chromatography, and it searched for new sources of nutritionally valuable compounds. According to the study’s findings, Sargassum muticum contains the highest levels of extractable bioactive compounds, showing a phenolic compound content of 235.67 ± 1.13 µg GAE·mg⁻¹ and a total sugar content of 46.43 ± 0.12% DW. Both S. muticum and Dictyota dichotoma have high concentrations of good polyphenols, such as vanillin and chrysin. Another characteristic that sets brown algae apart is their composition. It showed that Cladophora laetevirens has an extracted bioactive compound content of 12.07% and a high capacity to scavenge ABTS⁺ radicals with a value of 78.65 ± 0.96 µg·mL⁻¹, indicating high antioxidant activity. In terms of antibacterial activity, S. muticum seaweed showed excellent growth inhibition. In conclusion, all five species of seaweed under investigation exhibited unique strengths, highlighting the variety of advantageous characteristics of these seaweeds, especially S. muticum. Full article

(This article belongs to the Special Issue Antioxidant and Anticancer Activities of Compounds Isolated from Seagrasses and Seaweeds)

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19 pages, 4616 KiB

Open AccessArticle

Green Seaweed Caulerpa racemosa as a Novel Non-Small Cell Lung Cancer Inhibitor in Overcoming Tyrosine Kinase Inhibitor Resistance: An Analysis Employing Network Pharmacology, Molecular Docking, and In Vitro Research

by Vincent Lau, Fahrul Nurkolis, Moon Nyeo Park, Didik Setyo Heriyanto, Nurpudji Astuti Taslim, Trina Ekawati Tallei, Happy Kurnia Permatasari, Raymond R. Tjandrawinata, Seungjoon Moon and Bonglee Kim

Mar. Drugs 2024, 22(6), 272; https://doi.org/10.3390/md22060272 - 12 Jun 2024

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Abstract

The marine environment provides a rich source of distinct creatures containing potentially revolutionary bioactive chemicals. One of these organisms is Caulerpa racemosa, a type of green algae known as green seaweed, seagrapes, or green caviar. This organism stands out because it has [...] Read more.

The marine environment provides a rich source of distinct creatures containing potentially revolutionary bioactive chemicals. One of these organisms is Caulerpa racemosa, a type of green algae known as green seaweed, seagrapes, or green caviar. This organism stands out because it has great promise for use in medicine, especially in the study of cancer. Through the utilization of computational modeling (in silico) and cellular laboratory experiments (in vitro), the chemical components included in the green seaweed C. racemosa were effectively analyzed, uncovering its capability to treat non-small cell lung cancer (NSCLC). The study specifically emphasized blocking SRC, STAT3, PIK3CA, MAPK1, EGFR, and JAK1 using molecular docking and in vitro. These proteins play a crucial role in the EGFR Tyrosine Kinase Inhibitor Resistance pathway in NSCLC. The chemical Caulersin (C2) included in C. racemosa extract (CRE) has been identified as a potent and effective agent in fighting against non-small cell lung cancer (NSCLC), both in silico and in vitro. CRE and C2 showed a level of inhibition similar to that of osimertinib (positive control/NSCLC drug). Full article

(This article belongs to the Special Issue Marine Drug Discovery through Molecular Docking)

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14 pages, 2528 KiB

Open AccessReview

Exploring Sources, Biological Functions, and Potential Applications of the Ubiquitous Marine Cyclic Dipeptide: A Concise Review of Cyclic Glycine-Proline

by Lei Hu, **g Lin, Fei Qin, Li Xu and Lianzhong Luo

Mar. Drugs 2024, 22(6), 271; https://doi.org/10.3390/md22060271 - 12 Jun 2024

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Abstract

Cyclic glycine-proline (cGP), a prevalent marine cyclic dipeptide, possesses a distinct pyrrolidine-2,5-dione scaffold, which contributes to the chemical diversity and broad bioactivities of cGP. The diverse sources from marine-related, endogenous biological, and synthetic pathways and the in vitro and in [...] Read more.

Cyclic glycine-proline (cGP), a prevalent marine cyclic dipeptide, possesses a distinct pyrrolidine-2,5-dione scaffold, which contributes to the chemical diversity and broad bioactivities of cGP. The diverse sources from marine-related, endogenous biological, and synthetic pathways and the in vitro and in vivo activities of cGP are reviewed. The potential applications for cGP are also explored. In particular, the pivotal roles of cGP in regulating insulin-like growth factor-1 homeostasis, enhancing neuroprotective effects, and improving neurotrophic function in central nervous system diseases are described. The potential roles of this endogenous cyclic peptide in drug development and healthcare initiatives are also highlighted. This review underscores the significance of cGP as a fundamental building block in drug discovery with exceptional drug-like properties and safety. By elucidating the considerable value of cGP, this review aims to reignite interest in cGP-related research within marine medicinal chemistry and synthetic biology. Full article

(This article belongs to the Special Issue Bioactive Compounds from the Deep-Sea-Derived Microorganisms 2.0)

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10 pages, 2309 KiB

Open AccessArticle

Secondary Metabolites with Agricultural Antagonistic Potential from Aspergillus sp. ITBBc1, a Coral-Associated Marine Fungus

by Ailiman Abulaizi, Rong Wang, Zijun **ong, Shiqing Zhang, Yuanchao Li, Huiming Ge and Zhikai Guo

Mar. Drugs 2024, 22(6), 270; https://doi.org/10.3390/md22060270 - 11 Jun 2024

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Abstract

A marine-derived fungal strain, Aspergillus sp. ITBBc1, was isolated from coral collected from the South China Sea in Hainan province. Intensive chemical investigation of the fermentation extract of this strain afforded four new secondary metabolites (1–4), named megastigmanones A–C [...] Read more.

A marine-derived fungal strain, Aspergillus sp. ITBBc1, was isolated from coral collected from the South China Sea in Hainan province. Intensive chemical investigation of the fermentation extract of this strain afforded four new secondary metabolites (1–4), named megastigmanones A–C and prenylterphenyllin H, along with four known compounds (5–8). Their structures were elucidated by extensive spectroscopic analysis including one-and two-dimensional (1D and 2D) NMR spectroscopy and high-resolution electrospray ionization mass spectrometry (HR-ESI-MS). The modified Mosher’s method was undertaken to determine the absolute configurations of new compounds. The phytotoxic activity test showed that compounds 6–8 exhibited significant antagonistic activity against the germination of Triticum aestivum L. and Oryza sativa L. seeds with a dose-dependent relationship. Full article

(This article belongs to the Special Issue Bioactive Metabolites from Marine-Derived Penicillium or Aspergillus Species)

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16 pages, 3543 KiB

Open AccessArticle

Multifunctional Cell Regulation Activities of the Mussel Lectin SeviL: Induction of Macrophage Polarization toward the M1 Functional Phenotype

by Yuki Fujii, Kenichi Kamata, Marco Gerdol, Imtiaj Hasan, Sultana Rajia, Sarkar M. A. Kawsar, Somrita Padma, Bishnu Pada Chatterjee, Mayuka Ohkawa, Ryuya Ishiwata, Suzuna Yoshimoto, Masao Yamada, Namiho Matsuzaki, Keita Yamamoto, Yuka Niimi, Nobumitsu Miyanishi, Masamitsu Konno, Alberto Pallavicini, Tatsuya Kawasaki, Yukiko Ogawa, Yasuhiro Ozeki and Hideaki Fujita Show full author list Hide full author list

Mar. Drugs 2024, 22(6), 269; https://doi.org/10.3390/md22060269 - 11 Jun 2024

Viewed by 662

Abstract

SeviL, a galactoside-binding lectin previously isolated from the mussel Mytilisepta virgata, was demonstrated to trigger apoptosis in HeLa ovarian cancer cells. Here, we show that this lectin can promote the polarization of macrophage cell lines toward an M1 functional phenotype at low [...] Read more.

SeviL, a galactoside-binding lectin previously isolated from the mussel Mytilisepta virgata, was demonstrated to trigger apoptosis in HeLa ovarian cancer cells. Here, we show that this lectin can promote the polarization of macrophage cell lines toward an M1 functional phenotype at low concentrations. The administration of SeviL to monocyte and basophil cell lines reduced their growth in a dose-dependent manner. However, low lectin concentrations induced proliferation in the RAW264.7 macrophage cell line, which was supported by the significant up-regulation of TOM22, a component of the mitochondrial outer membrane. Furthermore, the morphology of lectin-treated macrophage cells markedly changed, shifting from a spherical to an elongated shape. The ability of SeviL to induce the polarization of RAW264.7 cells to M1 macrophages at low concentrations is supported by the secretion of proinflammatory cytokines and chemokines, as well as by the enhancement in the expression of IL-6- and TNF-α-encoding mRNAs, both of which encode inflammatory molecular markers. Moreover, we also observed a number of accessory molecular alterations, such as the activation of MAP kinases and the JAK/STAT pathway and the phosphorylation of platelet-derived growth factor receptor-α, which altogether support the functional reprogramming of RAW264.7 following SeviL treatment. These results indicate that this mussel β-trefoil lectin has a concentration-dependent multifunctional role in regulating cell proliferation, phenotype, and death in macrophages, suggesting its possible involvement in regulating hemocyte activity in vivo. Full article

(This article belongs to the Special Issue Marine Glycomics 2nd Edition)

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13 pages, 1539 KiB

Open AccessArticle

Cellulamides: A New Family of Marine-Sourced Linear Peptides from the Underexplored Cellulosimicrobium Genus

by Mariana Girão, José Murillo-Alba, Jesús Martín, Ignacio Pérez-Victoria, Ricardo B. Leite, Ralph Urbatzka, Pedro N. Leão, Maria F. Carvalho and Fernando Reyes

Mar. Drugs 2024, 22(6), 268; https://doi.org/10.3390/md22060268 - 11 Jun 2024

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Abstract

Bioprospecting the secondary metabolism of underexplored Actinomycetota taxa is a prolific route to uncover novel chemistry. In this work, we report the isolation, structure elucidation, and bioactivity screening of cellulamides A and B (1 and 2), two novel linear peptides obtained [...] Read more.

Bioprospecting the secondary metabolism of underexplored Actinomycetota taxa is a prolific route to uncover novel chemistry. In this work, we report the isolation, structure elucidation, and bioactivity screening of cellulamides A and B (1 and 2), two novel linear peptides obtained from the culture of the macroalga-associated Cellulosimicrobium funkei CT-R177. The host of this microorganism, the Chlorophyta Codium tomentosum, was collected in the northern Portuguese coast and, in the scope of a bioprospecting study focused on its associated actinobacterial community, strain CT-R177 was isolated, taxonomically identified, and screened for the production of antimicrobial and anticancer compounds. Dereplication of a crude extract of this strain using LC-HRMS(/MS) analysis unveiled a putative novel natural product, cellulamide A (1), that was isolated following mass spectrometry-guided fractionation. An additional analog, cellulamide B (2) was obtained during the chromatographic process and chemically characterized. The chemical structures of the novel linear peptides, including their absolute configurations, were elucidated using a combination of HRMS, 1D/2D NMR spectroscopy, and Marfey’s analysis. Cellulamide A (1) was subjected to a set of bioactivity screenings, but no significant biological activity was observed. The cellulamides represent the first family of natural products reported from the Actinomycetota genus Cellulosimicrobium, showcasing not only the potential of less-explored taxa but also of host-associated marine strains for novel chemistry discovery. 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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13 pages, 2442 KiB

Open AccessArticle

Purification and Characterization of a Novel Fibrinolytic Enzyme from Marine Bacterium Bacillus sp. S-3685 Isolated from the South China Sea

by Zibin Ma, Jeevithan Elango, Jianhua Hao and Wenhui Wu

Mar. Drugs 2024, 22(6), 267; https://doi.org/10.3390/md22060267 - 10 Jun 2024

Viewed by 524

Abstract

A novel fibrinolytic enzyme, BSFE1, was isolated from the marine bacterium Bacillus sp. S-3685 (GenBank No.: KJ023685) found in the South China Sea. This enzyme, with a molecular weight of approximately 42 kDa and a specific activity of 736.4 U/mg, exhibited its highest [...] Read more.

A novel fibrinolytic enzyme, BSFE1, was isolated from the marine bacterium Bacillus sp. S-3685 (GenBank No.: KJ023685) found in the South China Sea. This enzyme, with a molecular weight of approximately 42 kDa and a specific activity of 736.4 U/mg, exhibited its highest activity at 37 °C in a phosphate buffer at pH 8.0. The fibrinolytic enzyme remained stable over a pH range of 7.5 to 10.0 and retained about 76% of its activity after being incubated at 37 °C for 2 h. The K_m and V_max values of the enzyme at 37 °C were determined to be 2.1 μM and 49.0 μmol min⁻¹ mg⁻¹, respectively. The fibrinolytic activity of BSFE1 was enhanced by Na⁺, Ba²⁺, K⁺, Co²⁺, Mn²⁺, Al³⁺, and Cu²⁺, while it was inhibited by Fe³⁺, Ca²⁺, Mg²⁺, Zn²⁺, and Fe²⁺. These findings indicate that the fibrinolytic enzyme isolated in this study exhibits a strong affinity for fibrin. Moreover, the enzyme we have purified demonstrates thrombolytic enzymatic activity. These characteristics make BSFE1 a promising candidate for thrombolytic therapy. In conclusion, the results obtained from this study suggest that our work holds potential in the development of agents for thrombolytic treatment. Full article

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

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15 pages, 3527 KiB

Open AccessArticle

Halenaquinol Blocks Staphylococcal Protein A Anchoring on Cell Wall Surface by Inhibiting Sortase A in Staphylococcus aureus

by Jaepil Lee, Jae-Hyeong Choi, Jayho Lee, Eunji Cho, Yeon-Ju Lee, Hyi-Seung Lee and Ki-Bong Oh

Mar. Drugs 2024, 22(6), 266; https://doi.org/10.3390/md22060266 - 10 Jun 2024

Viewed by 506

Abstract

Sortase A (SrtA) is a cysteine transpeptidase that binds to the periplasmic membrane and plays a crucial role in attaching surface proteins, including staphylococcal protein A (SpA), to the peptidoglycan cell wall. Six pentacyclic polyketides (1–6) were isolated from [...] Read more.

Sortase A (SrtA) is a cysteine transpeptidase that binds to the periplasmic membrane and plays a crucial role in attaching surface proteins, including staphylococcal protein A (SpA), to the peptidoglycan cell wall. Six pentacyclic polyketides (1–6) were isolated from the marine sponge Xestospongia sp., and their structures were elucidated using spectroscopic techniques and by comparing them to previously reported data. Among them, halenaquinol (2) was found to be the most potent SrtA inhibitor, with an IC₅₀ of 13.94 μM (4.66 μg/mL). Semi-quantitative reverse transcription PCR data suggest that halenaquinol does not inhibit the transcription of srtA and spA, while Western blot analysis and immunofluorescence microscopy images suggest that it blocks the cell wall surface anchoring of SpA by inhibiting the activity of SrtA. The onset and magnitude of the inhibition of SpA anchoring on the cell wall surface in S. aureus that has been treated with halenaquinol at a value 8× that of the IC₅₀ of SrtA are comparable to those for an srtA-deletion mutant. These findings contribute to the understanding of the mechanism by which marine-derived pentacyclic polyketides inhibit SrtA, highlighting their potential as anti-infective agents targeting S. aureus virulence. Full article

(This article belongs to the Section Marine Pharmacology)

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15 pages, 3785 KiB

Open AccessArticle

Purification and Structural Analyses of Sulfated Polysaccharides from Low-Value Sea Cucumber Stichopus naso and Anticoagulant Activities of Its Oligosaccharides

by Lige Cui, Huifang Sun, **aolei Shang, **g Wen, Pengfei Li, Shengtao Yang, Linxia Chen, **angyang Huang, Haoyang Li, Ronghua Yin and **hua Zhao

Mar. Drugs 2024, 22(6), 265; https://doi.org/10.3390/md22060265 - 8 Jun 2024

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Abstract

Three polysaccharides (SnNG, SnFS and SnFG) were purified from the body wall of Stichopus naso. The physicochemical properties, including monosaccharide composition, molecular weight, sulfate content, and optical rotation, were analyzed, confirming that SnFS and SnFG are sulfated polysaccharides commonly found in sea [...] Read more.

Three polysaccharides (SnNG, SnFS and SnFG) were purified from the body wall of Stichopus naso. The physicochemical properties, including monosaccharide composition, molecular weight, sulfate content, and optical rotation, were analyzed, confirming that SnFS and SnFG are sulfated polysaccharides commonly found in sea cucumbers. The highly regular structure {3)-L-Fuc_2S-(α1,}_n of SnFS was determined via a detailed NMR analysis of its oxidative degradation product. By employing β-elimination depolymerization of SnFG, tri-, penta-, octa-, hendeca-, tetradeca-, and heptadeca-saccharides were obtained from the low-molecular-weight product. Their well-defined structures confirmed that SnFG possessed the backbone of {D-GalNAc_4S6S-β(1,4)-D-GlcA}, and each GlcA residue was branched with Fuc_2S4S. SnFS and SnFG are both structurally the simplest version of natural fucan sulfate and fucosylated glycosaminoglycan, facilitating the application of low-value sea cucumbers S. naso. Bioactivity assays showed that SnFG and its derived oligosaccharides exhibited potent anticoagulation and intrinsic factor Xase (iXase) inhibition. Moreover, a comparative analysis with the series of oligosaccharides solely branched with Fuc_3S4S showed that in oligosaccharides with lower degrees of polymerization, such as octasaccharides, Fuc_2S4S led to a greater increase in APTT prolongation and iXase inhibition. As the degree of polymerization increases, the influence from the sulfation pattern diminishes, until it is overshadowed by the effects of molecular weight. Full article

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

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22 pages, 1623 KiB

Open AccessArticle

Status of Fishery Discards and By-Products in Greece and Potential Valorization Scenarios towards a National Exploitation Master Plan

by Efstratios Roussos, George Triantaphyllidis, Vassiliki Ilia, Konstantinos Tsagarakis, Athanasios Machias, Leto-Aikaterini Tziveleka, Vassilios Roussis, Efstathia Ioannou and Yannis Kotzamanis

Mar. Drugs 2024, 22(6), 264; https://doi.org/10.3390/md22060264 - 7 Jun 2024

Viewed by 630

Abstract

The valorization of aquaculture/fishery processing by-products, as well as unavoidable/unwanted catches and discards in Greece, is currently an underutilized activity despite the fact that there are several best practices in Northern Europe and overseas. One of the main challenges is to determine whether [...] Read more.

The valorization of aquaculture/fishery processing by-products, as well as unavoidable/unwanted catches and discards in Greece, is currently an underutilized activity despite the fact that there are several best practices in Northern Europe and overseas. One of the main challenges is to determine whether the available quantities for processing are sufficient to warrant the valorization of discards and fish side streams. This is the first attempt to systematically record and analyze the available quantities of fish by-products and discards in Greece spatially and temporally in an effort to create a national exploitation Master Plan for the valorization of this unavoidable and unwanted biomass. A thorough survey conducted within the VIOAXIOPIO project unveiled a substantial biomass of around 19,000 tonnes annually that could be harnessed for valorization. Furthermore, the production of various High-Added-Value Biomolecules (HAVBs) was investigated and experimental trials were conducted to assess the potential yields, with the collected data used to formulate four valorization scenarios. Full article

(This article belongs to the Special Issue Fishery Discards, Processing Waste and Marine By-Products)

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15 pages, 1932 KiB

Open AccessArticle

Elements in Serum, Muscle, Liver, and Kidney of Rabbits Fed Macroalgae-Supplemented Diets

by Sabela Al-Soufi, Marta Miranda, Javier García, Antonio Muíños, Eugenio Cegarra, Nuria Nicodemus, Carlos Herrero-Latorre and Marta López-Alonso

Mar. Drugs 2024, 22(6), 263; https://doi.org/10.3390/md22060263 - 7 Jun 2024

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Abstract

The addition of marine macroalgae to animal feed has garnered interest due to the demonstrated benefits of gut health in many livestock species. Most macroalgae have a higher mineral content than terrestrial vegetables, making them an attractive, sustainable source of minerals. However, some [...] Read more.

The addition of marine macroalgae to animal feed has garnered interest due to the demonstrated benefits of gut health in many livestock species. Most macroalgae have a higher mineral content than terrestrial vegetables, making them an attractive, sustainable source of minerals. However, some macroalgae contain elevated concentrations of iodine and arsenic, which may be transferred to the meat of livestock fed with macroalgae. This study evaluated the mineral profile of rabbit serum, muscle, liver, and kidney of rabbits fed diets supplemented with different marine macroalgae, with the goal of improving post-weaning gut health and reducing reliance on antibiotics. We found increased deposition of iodine in muscle, liver, and kidney due to macroalgae supplementation, which is particularly promising for regions with low iodine endemicity. Higher, though relatively low arsenic concentrations, compared to those in other animal meats and food sources, were also detected in the muscle, liver, and kidney of macroalgae-fed rabbits. The absence of apparent interactions with other micronutrients, particularly selenium, suggests that the inclusion of macroalgae in rabbit diets will not affect the overall mineral content. Enhanced bioavailability of elements such as phosphorus and iron may provide additional benefits, potentially reducing the need for mineral supplementation. Full article

(This article belongs to the Special Issue Marine Natural Products in Anti-obesity and Metabolic Syndrome)

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9 pages, 1036 KiB

Open AccessCommunication

The Discovery of Cyclic Lipopeptide Olenamidonins in a Deepsea-Derived Streptomyces Strain by Knocking Out a DtxR Family Regulator

by Qiannan Sun, Dongqi Yu, Xueqing Zhang, Fei **ao and Wenli Li

Mar. Drugs 2024, 22(6), 262; https://doi.org/10.3390/md22060262 - 6 Jun 2024

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Abstract

Three new cyclic lipopeptides, olenamidonins A-C (1–3), in addition to two previously reported metabolites (4 and 5), were accumulated in the ΔdtxR_so deletion mutant of deepsea-derived Streptomyces olivaceus SCSIO 1071. The structures of these cyclic [...] Read more.

Three new cyclic lipopeptides, olenamidonins A-C (1–3), in addition to two previously reported metabolites (4 and 5), were accumulated in the ΔdtxR_so deletion mutant of deepsea-derived Streptomyces olivaceus SCSIO 1071. The structures of these cyclic lipopeptides were determined by a combination of spectroscopic methods and circular dichroism (CD) measurement. The antibacterial assay results showed that compounds 1–5 displayed different degrees of growth inhibition against multidrug-resistant (MDR) bacterial strains Enterococcus faecalis CCARM 5172 and Enterococcus faecium CCARM 5203 with minimum inhibitory concentrations (MICs) of 1.56−6.25 μg/mL. Full article

(This article belongs to the Special Issue Bioactive Natural Products from the Deep-Sea-Sourced Microbes)

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11 pages, 1964 KiB

Open AccessArticle

Quality Assessment of Fish Oil Obtained after Enzymatic Hydrolysis of a Mixture of Rainbow Trout (Oncorhynchus mykiss) and Atlantic Salmon (Salmo salar) Rest Raw Material Pretreated by High Pressure

by Elissavet Kotsoni, Egidijus Daukšas, Grete Hansen Aas, Turid Rustad, Brijesh K. Tiwari and Janna Cropotova

Mar. Drugs 2024, 22(6), 261; https://doi.org/10.3390/md22060261 - 5 Jun 2024

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Abstract

Utilization of fish rest raw material for fish oil extraction has received interest with the increasing demand for sustainable food sources. Enzymatic hydrolysis is an efficient method for the extraction of value-added compounds, but its effectiveness may be enhanced by high-pressure processing (HPP). [...] Read more.

Utilization of fish rest raw material for fish oil extraction has received interest with the increasing demand for sustainable food sources. Enzymatic hydrolysis is an efficient method for the extraction of value-added compounds, but its effectiveness may be enhanced by high-pressure processing (HPP). However, HPP can induce lipid oxidation, affecting the quality of the oil. This study aimed to evaluate the quality of fish oil obtained after enzymatic hydrolysis of a mixture of rainbow trout (Oncorhynchus mykiss) and Atlantic salmon (Salmo salar) rest raw material pretreated by HPP. Six pretreatments were tested prior to enzymatic hydrolysis; 200 MPa × 4 min, 200 MPa × 8 min, 400 MPa × 4 min, 400 MPa × 8 min, 600 MPa × 4 min, and 600 MPa × 8 min. The oil samples were analyzed for lipid oxidation parameters, free fatty acid content, fatty acid composition, and color changes over 8 weeks. The results confirmed that HPP may induce lipid oxidation and revealed significant influence of HPP parameters on lipid oxidation, with higher pressures leading to increased oxidation. Fatty acid composition varied among samples, but it was not substantially affected by HPP. Full article

(This article belongs to the Special Issue Fishery Discards, Processing Waste and Marine By-Products)

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19 pages, 6277 KiB

Open AccessArticle

TRAF6 Inhibitors from Marine Compound Library: Pharmacophore, Virtual Screening, Fragment Replacement, ADMET, and Molecular Dynamics

by Xuexuan Wu, Saiyi Zhong, Nan Zhou and Lianxiang Luo

Mar. Drugs 2024, 22(6), 260; https://doi.org/10.3390/md22060260 - 5 Jun 2024

Viewed by 539

Abstract

TRAF6 is an E3 ubiquitin ligase that plays a crucial role in cell signaling. It is known that MMP is involved in tumor metastasis, and TRAF6 induces MMP-9 expression by binding to BSG. However, inhibiting TRAF6’s ubiquitinase activity without disrupting the RING domain [...] Read more.

TRAF6 is an E3 ubiquitin ligase that plays a crucial role in cell signaling. It is known that MMP is involved in tumor metastasis, and TRAF6 induces MMP-9 expression by binding to BSG. However, inhibiting TRAF6’s ubiquitinase activity without disrupting the RING domain is a challenge that requires further research. To address this, we conducted computer-based drug screening to identify potential TRAF6 inhibitors. Using a ligand–receptor complex pharmacophore based on the inhibitor EGCG, known for its anti-tumor properties, we screened 52,765 marine compounds. After the molecular docking of 405 molecules with TRAF6, six compounds were selected for further analysis. By replacing fragments of non-binding compounds and conducting second docking, we identified two promising molecules, CMNPD9212-16 and CMNPD12791-8, with strong binding activity and favorable pharmacological properties. ADME and toxicity predictions confirmed their potential as TRAF6 inhibitors. Molecular dynamics simulations showed that CMNPD12791-8 maintained a stable structure with the target protein, comparable to EGCG. Therefore, CMNPD12791-8 holds promise as a potential inhibitor of TRAF6 for inhibiting tumor growth and metastasis. Full article

(This article belongs to the Special Issue Bioinformatics of Marine Natural Products 3.0)

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11 pages, 1552 KiB

Open AccessArticle

Chrysomycins, Anti-Tuberculosis C-Glycoside Polyketides from Streptomyces sp. MS751

by Jiaming Yu, Hui Guo, **g Zhang, Jiansen Hu, Hongtao He, Caixia Chen, Na Yang, Fan Yang, Zexu Lin, Huanqin Dai, Liming Ouyang, Cuihua Liu, **aoguang Lei, Lixin Zhang, Guoliang Zhu and Fuhang Song

Mar. Drugs 2024, 22(6), 259; https://doi.org/10.3390/md22060259 - 3 Jun 2024

Viewed by 511

Abstract

A new dimeric C-glycoside polyketide chrysomycin F (1), along with four new monomeric compounds, chrysomycins G (2), H (3), I (4), J (5), as well as three known analogues, chrysomycins A (6 [...] Read more.

A new dimeric C-glycoside polyketide chrysomycin F (1), along with four new monomeric compounds, chrysomycins G (2), H (3), I (4), J (5), as well as three known analogues, chrysomycins A (6), B (7), and C (8), were isolated and characterised from a strain of Streptomyces sp. obtained from a sediment sample collected from the South China Sea. Their structures were determined by detailed spectroscopic analysis. Chrysomycin F contains two diastereomers, whose structures were further elucidated by a biomimetic [2 + 2] photodimerisation of chrysomycin A. Chrysomycins B and C showed potent anti-tuberculosis activity against both wild-type Mycobacterium tuberculosis and a number of clinically isolated MDR M. tuberculosis strains. Full article

(This article belongs to the Special Issue Marine Streptomyces-Derived Natural Products 2024)

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15 pages, 2188 KiB

Open AccessArticle

Distribution and Level of Bioactive Monoacylglycerols in 12 Marine Microalgal Species

by Giovanna Santaniello, Gianna Falascina, Marcello Ziaco, Laura Fioretto, Angela Sardo, Martina Carelli, Mariarosaria Conte, Giovanna Romano and Adele Cutignano

Mar. Drugs 2024, 22(6), 258; https://doi.org/10.3390/md22060258 - 31 May 2024

Viewed by 680

Abstract

Microalgae are currently considered an attractive source of highly valuable metabolites potentially exploitable as anticancer agents, nutraceuticals and cosmeceuticals and for bioenergy purposes. Their ease of culturing and their high growth rates further promote their use as raw material for the production of [...] Read more.

Microalgae are currently considered an attractive source of highly valuable metabolites potentially exploitable as anticancer agents, nutraceuticals and cosmeceuticals and for bioenergy purposes. Their ease of culturing and their high growth rates further promote their use as raw material for the production of specialty products. In the present paper, we focused our attention on specific glycerol-based lipid compounds, monoacylglycerols (MAGs), which displayed in our previous studies a selective cytotoxic activity against the haematological U-937 and the colon HCT-116 cancer cell lines. Here, we performed a quali/quantitative analysis of MAGs and total fatty acids (FAs) along with a profiling of the main lipid classes in a panel of 12 microalgal species, including diatoms and dinoflagellates. Our results highlight an inter- and intraspecific variability of MAG profile in the selected strains. Among them, Skeletonema marinoi (strain FE7) has emerged as the most promising source for possible biotechnological production of MAGs. Full article

(This article belongs to the Special Issue Biotechnological Applications of Marine Microalgae)

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