Marine DrugsPub Date : 2026-08-21DOI: 10.3390/md24080290
Zhuling Shao, Luya Wang, Xin Wang
{"title":"Structural Characterization and Biological Evaluation of a Novel GlcNAc-Bearing Exopolysaccharide from the Mangrove Endophytic Fungus <i>Penicillium janthinellum</i> N29.","authors":"Zhuling Shao, Luya Wang, Xin Wang","doi":"10.3390/md24080290","DOIUrl":"10.3390/md24080290","url":null,"abstract":"<p><p>A novel, uniform acid heteropolysaccharide with a molecular weight of 13.14 kDa was isolated from the fermented broth of the mangrove endophytic fungus <i>Penicillium janthinellum</i> N29, designated as PJ3-1. A structural analysis showed that PJ3-1 is a straight-chain heteropolysaccharide containing GlcN, GlcNAc, Glc and GlcA in the ratio of 12.23:1.79:10.93:1.00. PJ3-1 markedly inhibits α-glucosidase activity and relieves insulin resistance in HepG2 cells. It alleviates lipid peroxidation and upregulates the activities of endogenous antioxidant enzymes. In addition, it also significantly scavenges hydroxyl radicals, ferrous ions, superoxide anions, DPPH radicals and ABTS radicals and enhances reducing power in a dose-dependent manner. Collectively, these findings suggest that PJ3-1 has the potential to serve as a natural antioxidant and hypoglycemic agent for functional food or pharmaceutical applications.</p>","PeriodicalId":18222,"journal":{"name":"Marine Drugs","volume":"24 8","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13514933/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148829781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Marine DrugsPub Date : 2026-08-21DOI: 10.3390/md24080291
Hyeon Seung Park, Min Seo Heo, Hyuk Nam Kwon, Yo Han Jang, Munhyung Bae, Yun Kwon
{"title":"Marine-Derived Natural Products Against Flaviviruses: Mechanisms, Evidence, and Future Directions.","authors":"Hyeon Seung Park, Min Seo Heo, Hyuk Nam Kwon, Yo Han Jang, Munhyung Bae, Yun Kwon","doi":"10.3390/md24080291","DOIUrl":"10.3390/md24080291","url":null,"abstract":"<p><p>Although flaviviruses, including DENV, ZIKV and JEV, remain important causes of febrile, congenital, and neurological diseases, treatment options remain largely supportive, with limited availability of virus-specific antiviral therapies. Marine organisms and marine-derived microorganisms produce chemically distinct antiviral materials, including sulfated polysaccharides, terpenoids, alkaloids, peptides, cyclodepsipeptides, and polyketides. However, their activities range from preliminary extract-level inhibition to direct biochemical target validation, making mechanistic comparison difficult. This review critically evaluates marine-derived anti-flaviviral agents using two complementary dimensions, the infection stage implicated by experimental assays and the strength of evidence supporting that assignment. DENV evidence is dominated by sulfated algal macromolecules that interfere with adsorption or internalization, whereas ZIKV studies encompass lipophilic algal metabolites, fungal alkaloids, cyclodepsipeptides, and a few target-oriented candidates. Across the field, most reports remain stage-associated rather than target-validated. Cross-study potency comparisons are constrained by differences in virus strains, cell models, assay formats, and treatment schedules. JEV-specific evidence is particularly sparse. Based on the DENV and ZIKV evidence map, we propose concise priorities for JEV-oriented discovery: early compound-level dereplication, parallel cytotoxicity testing, orthogonal confirmation of productive infection, stage-resolved assays, and biochemical or genetic validation of conserved flaviviral targets. This evidence-based framework can help distinguish promising chemical candidate scaffolds from preliminary antiviral signals and guide mechanism-informed development of marine-derived natural products against flaviviruses.</p>","PeriodicalId":18222,"journal":{"name":"Marine Drugs","volume":"24 8","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13514377/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148829706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Stigmasterol-Stabilized Nanoliposomes Enhance Oral Delivery of Collagen Peptides Through Improved Systemic Exposure of Hydroxyproline-Containing Peptides.","authors":"Zifang Zhao, Wenshuo Xing, Meichao Zhang, Chengsuo Liu, Weijie Zhang, Haohao Wu, Changhu Xue","doi":"10.3390/md24080293","DOIUrl":"10.3390/md24080293","url":null,"abstract":"<p><p>Collagen peptides (CPs) possess diverse biological activities, yet their oral efficacy is limited by gastrointestinal degradation and restricted systemic exposure of intact bioactive peptide species. Herein, a stable cholesterol-free nanoliposome system was developed using soybean phospholipids and stigmasterol through high-pressure microfluidization, followed by tangential flow filtration and spray drying to obtain a stable dry formulation. The optimized nanoliposomes exhibited a particle size below 100 nm, high peptide loading, excellent redispersibility, and remarkable physicochemical stability during refrigerated storage and under different pH and thermal conditions. During simulated gastrointestinal digestion, the stigmasterol-stabilized phospholipid bilayer effectively preserved encapsulated CPs throughout the gastric phase while facilitating peptide release under intestinal conditions. Oral administration in rats significantly enhanced collagen peptide bioavailability, increasing the plasma exposure (iAUC<sub>0-8 h</sub>) of total hydroxyproline by 3.84-fold compared with free CPs. Peptide-bound hydroxyproline exposure increased 9.3-fold and accounted for approximately 94% of total absorbed hydroxyproline. UHPLC-HRMS analysis confirmed substantially enhanced systemic exposure of multiple characteristic hydroxyproline-containing dipeptides and tripeptides following nanoliposomal delivery. These findings indicate that stigmasterol-containing nanoliposomes improve the gastrointestinal stability and systemic delivery performance of collagen peptides, providing a promising strategy for enhancing the oral delivery potential of food-derived bioactive peptides.</p>","PeriodicalId":18222,"journal":{"name":"Marine Drugs","volume":"24 8","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13514345/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148829810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Marine DrugsPub Date : 2026-08-20DOI: 10.3390/md24080286
Yunhan Li, Xinhong Wang, Xiang Li, Nan Wei, Dawei Jiang, Ming Li, Chong Yu, Juan Guo, Keqiang Li, Haifeng Wang, Ning Li
{"title":"Marine Food Polysaccharides: Representative Structural Features, Immunomodulatory Effects, and Food Applications.","authors":"Yunhan Li, Xinhong Wang, Xiang Li, Nan Wei, Dawei Jiang, Ming Li, Chong Yu, Juan Guo, Keqiang Li, Haifeng Wang, Ning Li","doi":"10.3390/md24080286","DOIUrl":"10.3390/md24080286","url":null,"abstract":"<p><p>Marine food polysaccharides (MFPs) are structurally diverse biopolymers shaped by the marine environment, with emerging roles in immune regulation and food design. This review summarizes the representative structural features of MFPs, and evaluates their effects on innate and adaptive immune responses and associated signaling pathways. The influences of molecular weight, sulfation, branching, and monosaccharide composition on biological activity are also discussed. In addition, this review discusses the applications of MFPs in food additives, packaging, delivery systems, and functional foods. Despite growing evidence, challenges remain in resolving higher-order structures, understanding bidirectional immune effects and maintaining stability in complex matrices. Advancing integrated structural and food design approaches could enable the rational use of MFPs as next-generation functional ingredients.</p>","PeriodicalId":18222,"journal":{"name":"Marine Drugs","volume":"24 8","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13514180/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148829597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Marine DrugsPub Date : 2026-08-19DOI: 10.3390/md24080285
Xiaoyuan Su, Hailiang Xing, Kai Liu, Ya Zhao, Lijin Dong, Ziyan Zhou, Na Zhou, Xue Sun, Liuquan Zhang, Nianjun Xu, Chaoyang Hu
{"title":"Synergistic Application of Cytidine Monophosphate and Sodium Chloride for Enhanced Co-Production of Astaxanthin and Fatty Acids in <i>Haematococcus lacustris</i> Motile Cells Under High-Light Stress.","authors":"Xiaoyuan Su, Hailiang Xing, Kai Liu, Ya Zhao, Lijin Dong, Ziyan Zhou, Na Zhou, Xue Sun, Liuquan Zhang, Nianjun Xu, Chaoyang Hu","doi":"10.3390/md24080285","DOIUrl":"10.3390/md24080285","url":null,"abstract":"<p><p>This study evaluated the synergistic effects of sodium chloride (NaCl) and cytidine monophosphate (CMP) on enhancing the co-production of astaxanthin and fatty acids while suppressing secondary cell wall (SCW) formation in <i>Haematococcus lacustris</i> (synonym: <i>H. pluvialis</i>) under high-light stress. An orthogonal design identified the optimal combination (0.5 g/L NaCl and 0.5 mM CMP), which significantly increased astaxanthin yield by over 35.6% and total fatty acid yield by 28%, while maintaining 96.8% of cells in motile state (SCW-deficient). Physiological analyses revealed elevated reactive oxygen species levels, concomitant with higher actual photochemical efficiency (Fv'/Fm') and relative electron transport rates II (rETR(II)) along with enhanced non-photochemical quenching (NPQ) capacity, and metabolic reprogramming characterized by the accumulation of lipids, sugars, and starch alongside decreased protein yield. Metabolomics indicated reduced carbon supply for SCW polysaccharide biosynthesis, coupled with decreased protein yield and altered amino acid profiles characteristic of nitrogen-limited metabolism, which collectively favored the reallocation of carbon resources toward nitrogen-free high-value products. Transcriptomics confirmed the downregulation of SCW component biosynthetic genes and the upregulation of the methylerythritol phosphate (MEP) pathway and astaxanthin biosynthetic pathway. Scale-up experiments validated this strategy for producing astaxanthin-rich motile cells, offering a promising approach for microalgal biorefinery.</p>","PeriodicalId":18222,"journal":{"name":"Marine Drugs","volume":"24 8","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13514649/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148829820","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Marine DrugsPub Date : 2026-08-19DOI: 10.3390/md24080284
Juwan Son, Hyeon Seung Park, Sang Heon Jung, Min Seo Heo, Yun Kwon, Munhyung Bae
{"title":"Marine-Derived Rare Actinomycetes: Metabolites and Their Biosynthesis.","authors":"Juwan Son, Hyeon Seung Park, Sang Heon Jung, Min Seo Heo, Yun Kwon, Munhyung Bae","doi":"10.3390/md24080284","DOIUrl":"10.3390/md24080284","url":null,"abstract":"<p><p>Marine-derived rare actinomycetes are a chemically prolific yet underexploited source of structurally diverse secondary metabolites. In this review, rare actinomycetes are operationally defined as marine-derived non-<i>Streptomyces</i> actinomycetes that remain comparatively underexplored yet possess demonstrated or predicted capacity for specialized-metabolite biosynthesis. Genome sequencing has revealed that their biosynthetic potential greatly exceeds the range of metabolites recovered under standard cultivation conditions. However, many reported compounds remain only loosely associated with the gene clusters that encode them. This review provides a biosynthesis-centered perspective on marine-derived rare actinomycetes, focusing on secondary metabolites for which biosynthetic gene clusters (BGCs) or pathways have been proposed, experimentally assessed, or functionally validated. It focuses on compounds reported after 2017, along with earlier metabolites whose biosynthetic origins were resolved only later. Representative examples are organized by genus and structural class and weighed according to the level of evidence linking each metabolite to its BGC, ranging from bioinformatic prediction and metabolomic correlation to validation by gene inactivation, heterologous expression, and enzymatic characterization. The surveyed metabolites include polyketides, nonribosomal peptides, polyketide synthase-nonribosomal peptide synthetase (PKS-NRPS) hybrids, siderophores, angucyclines, anthracyclines, macrolides, diketopiperazine derivatives, and other unusual scaffolds. Collectively, these findings indicate how integrating genome mining, metabolomics, and molecular networking with targeted biosynthetic experiments can accelerate marine natural product discovery and unravel novel enzymatic functions and biosynthetic mechanisms in rare actinomycetes.</p>","PeriodicalId":18222,"journal":{"name":"Marine Drugs","volume":"24 8","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13514850/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148829792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Marine DrugsPub Date : 2026-08-17DOI: 10.3390/md24080283
Jan Cichoński, Patrycja Michalik, Wiktor Nowak, Paweł Czerniewicz, Ewelina Kuna, Magdalena Słowik-Borowiec, Grzegorz Chrzanowski
{"title":"Concentration-Dependent Effects of Salicylic Acid and Methyl Salicylate on Chlorophylls, Carotenoids, Fatty Acids, and Phenolic Compounds in the Green Microalga <i>Planktochlorella nurekis</i>.","authors":"Jan Cichoński, Patrycja Michalik, Wiktor Nowak, Paweł Czerniewicz, Ewelina Kuna, Magdalena Słowik-Borowiec, Grzegorz Chrzanowski","doi":"10.3390/md24080283","DOIUrl":"10.3390/md24080283","url":null,"abstract":"<p><p>Microalgae are a rich source of bioactive metabolites, including unsaturated fatty acids, chlorophylls, carotenoids, and phenolic compounds with antioxidant and nutraceutical potential. Salicylic acid (SA) and its volatile ester, methyl salicylate (MS), are well-known elicitors of secondary metabolism in higher plants, yet their mechanisms of action in green microalgae, particularly the effects of MS, remain poorly understood. Therefore, we evaluated how salicylates applied at concentrations of 0.1, 1, and 10 µM affect the growth and accumulation of bioactive compounds in a high-productivity clone of <i>Planktochlorella nurekis</i>, combining gas chromatography coupled mass spectrometry (GC-MS) fatty acid profiling with spectrophotometric determination of pigment levels, total phenols, and L-phenylalanine ammonia-lyase (PAL) activity. SA increased cell number and size, whereas 0.1 µM MS resulted in a six-fold gain in cell number. Accordingly, 10 µM MS raised chlorophyll <i>b</i> levels-nearly three-fold (from 76 to 211 µg per g D.W.)-and total carotenoids-roughly four-fold (129 to 520 µg per g D.W.)-while both elicitors significantly increased the monounsaturated fatty acid fraction (from 29% to about 40%). Notably, 10 µM SA lowered the levels of saturated fatty acids. Moreover, 10 µM MS doubled the PAL activity and increased the total phenols by 17% compared to the control. Thus, SA and MS act as effective elicitors of high-value metabolites in <i>P. nurekis</i>.</p>","PeriodicalId":18222,"journal":{"name":"Marine Drugs","volume":"24 8","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13514797/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148829548","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Marine DrugsPub Date : 2026-08-16DOI: 10.3390/md24080282
Man Zhang, Haoyu Li, Feichao Du, Yuhua Li, Haixing Li
{"title":"Fucoxanthin Bioproduction from Marine Diatoms: Regulatory Strategies and Industrial Potential of <i>Phaeodactylum tricornutum</i> and <i>Odontella aurita</i>-A Review.","authors":"Man Zhang, Haoyu Li, Feichao Du, Yuhua Li, Haixing Li","doi":"10.3390/md24080282","DOIUrl":"10.3390/md24080282","url":null,"abstract":"<p><p>Fucoxanthin is a high-value marine xanthophyll with a unique epoxy-allene structure, predominantly produced by brown macroalgae and marine diatoms, and additionally reported in other heterokont lineages including chrysophytes and certain haptophytes. As a core light-harvesting pigment, it exhibits multiple bioactivities including lipid-lowering, antioxidant, and anti-inflammatory effects, with broad applications in functional foods, dietary supplements, and pharmaceuticals. Currently, over 70% of commercial fucoxanthin is extracted from brown macroalgae such as <i>Saccharina japonica</i> and <i>Undaria pinnatifida</i>. However, due to low endogenous pigment content and significant extraction losses, the industrial yield is only 0.05-0.1% of dry weight, failing to meet the growing downstream demand for stable high-purity supply. Marine diatoms, characterized by short growth cycles, high pigment content, and controllable culture conditions, have emerged as a core direction for industrial upgrading. Among them, <i>Phaeodactylum tricornutum</i> and <i>Odontella aurita</i> are the two most systematically studied high-yield strains with outstanding potential. This review adopts volumetric productivity (mg/(L·d)) as the core evaluation metric, which integrates biomass concentration, pigment content, and production cycle, and reflects industrial efficiency more reliably than single intracellular content data. We summarize high-yield induction methods from the dimensions of nutrient regulation, light optimization, exogenous induction, and strain improvement, and systematically compare downstream processing, safety profiles, and regulatory status between the two diatoms. Furthermore, we evaluate multi-product co-production potential and scale-up performance from a techno-economic perspective. This review provides a side-by-side benchmark of these two marine diatoms, offering a data-driven reference for process development and industrial deployment of microalgae-derived fucoxanthin.</p>","PeriodicalId":18222,"journal":{"name":"Marine Drugs","volume":"24 8","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13514920/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148829581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Integrated Multi-Omics Analysis of Antarctic Krill Oil in Alleviating DSS-Induced Colitis and Modulating Gut Microbiota in Mice.","authors":"Shuyin Yang, Xinnan Zhao, Tiantian Chen, Yichen Lin, Yan Di, Zhijun Tan, Ningning He, Shangyong Li, Jixing Peng","doi":"10.3390/md24080281","DOIUrl":"10.3390/md24080281","url":null,"abstract":"<p><p>Ulcerative colitis (UC) is a chronic inflammatory bowel disease with elusive etiology and limited therapeutic options, accompanied by potential side effects. In this study, to investigate the therapeutic potential of Antarctic krill oil (AKO) in a dextran sulfate sodium (DSS)-induced mouse colitis model, animal experiments, molecular assays, transcriptomics, metabolomics, and 16S rRNA gene sequencing were conducted. Our results revealed that supplementation of AKO significantly alleviated colitis symptoms, such as weight loss, and inflammatory responses. Moreover, multi-omics analyses demonstrated that AKO inhibited the PI3K/Akt signaling pathway, remodeled beneficial gut microbiota, and reshaped metabolite profiles associated with glycerolphospholipid metabolism. Remarkably, AKO alleviated DSS-induced colitis, accompanied by coordinated changes in the gut microbiota, metabolites, and transcriptome, which were associated with suppression of key inflammatory pathways. These findings present experimental evidence for the potential of AKO as a marine-based nutritional intervention for UC, and offer novel perspectives on microbiota-targeted therapies for inflammatory diseases.</p>","PeriodicalId":18222,"journal":{"name":"Marine Drugs","volume":"24 8","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13514700/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148829614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Marine DrugsPub Date : 2026-08-12DOI: 10.3390/md24080280
James Blee, Peter O'Hara, Jialun Wu, Conor O'Byrne, Thomas J P Smyth, Owen Kenny
{"title":"Transcriptomic Responses of MRSA to Penicillin-Modulating Phlorotannins Derived from <i>Pelvetia canaliculata</i>.","authors":"James Blee, Peter O'Hara, Jialun Wu, Conor O'Byrne, Thomas J P Smyth, Owen Kenny","doi":"10.3390/md24080280","DOIUrl":"10.3390/md24080280","url":null,"abstract":"<p><p>Methicillin-resistant <i>Staphylococcus aureus</i> (MRSA) infections contribute significantly to the mortality rate associated with antimicrobial resistance, while also increasing medical complications when compared to methicillin-sensitive isolates. Consequently, increasing the efficacy of β-lactams may alleviate the burden associated with this drug-pathogen combination. Dialysed extracts, derived from <i>Pelvetia canaliculata</i>, were further partitioned to generate phlorotannin enriched extracts (PEEs). Minimum inhibitory concentrations (MICs) of extracts were used to determine the antimicrobial and antibiotic-modulating activity against seven clinical MRSA isolates. Whole-transcriptomic sequencing was carried out to determine potential mechanisms of action on the strongest extract-antibiotic combination against an MRSA isolate, determined by the fractional inhibitory concentration index (FICI). The most pronounced β-lactam modulatory effects were seen in the >100 kDa PEE from <i>P. canaliculata</i> in conjunction with amoxicillin (MIC fold-reductions = 12.8-214), while >30 kDa PEE resulted in the strongest FIC index value when combined with penicillin (0.23), indicating a synergistic effect. Whole-transcriptome analysis of this treatment identified multiple differentially expressed genes (Log2FC +1/-1) of statistical significance (<i>p</i> adj < 0.05), namely related to accelerated autolysis, cell-envelope stability, protein synthesis, DNA replication, iron homeostasis and active transport. This study highlights preliminary transcriptomic evidence of biological processes associated with penicillin modulation by <i>P. canaliculata</i> > 30 kDa PEE, providing a foundation for further investigation of its antibiotic-modulating activity.</p>","PeriodicalId":18222,"journal":{"name":"Marine Drugs","volume":"24 8","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13514743/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148829789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}