Introduction. Phlorotannins are secondary metabolites produced mainly by brown seaweeds and belong to the class of polyphenolic compounds with diverse bioactivities. Storm-cast brown algae, a problem for coastal biocenoses, may be a valuable source of polyphenols. The Folin-Ciocalteu reagent (FCR) is the most commonly used for the quantification of total polyphenols in natural samples. Different spectrophotometric methods with FCR for the determination of phlorotannins in algae have been described in the literature. Aim. The primary aim of this study is to standardize and validate the spec-trophotometric determination of total phlorotannins using FCR and demonstrate its applicability to analysis of storm-cast and fresh algae. Materials and methods. A. nodosum samples were collected in sheltered beach on the Olenitsa Bay (66°27'15.7"N 35°18'20.4" E), Kandalaksha Gulf (White Sea, Russia) on two tidal levels: one located at low tide at a depth of 0.6–1.0 m (fresh) and the second was located at the supralittoral in the zone of wave splashing (storm-cast). Field sampling was carried out between June and September. The cleaned seaweed were transported to the laboratory, washed accu-rately with clean water, freeze-dried, ground into powder. Functional groups present in the algae were identified using Fourier Transform Infrared (FT-IR) spectroscopy. Spectrophotometric determination of total phlorotannins content (TPhC) with FCR was used and validated according to national and international guidelines. Results and discussion. The optimum conditions for analysis time, wave-length, and standard substance were 45 min, 750 nm, and phloroglucinol, respec-tively. Under these conditions, validation by UV/Vis spectrophotometry proved the method to be linear ( R 2 > 0.99), specific, precise, accurate, reproducible, robust, and easy to perform. The limit of detection and limit of quantification were 0.005 and 0.02 mg/mL, respectively. For precision analysis, an intra-day test (RSD 2.16 %) and an inter-day test (RSD 2.84 %) were performed. Matrix effect assessment demonstrated that this had a negligible effect (1.9 %) on the phlorotannins quantification. TPhC in storm-cast algae ranged from 59 to 101 mg/g, while freshly collected algae were statistically significantly higher ( p < 0.01) and ranged from 71 to 135 mg/g. Maximum accumulation of phlorotannins in A. nodosum was observed between July and August, after which a decrease was observed. Conclusion. Results of current study could be utilised for routine analysis of TPhC in brown algae and storm-cast seaweed using optimized spectrophotometric method with FCR on readily available low-cost equipment in most laboratories to provide rapid. This methodology complies with the requirements for pharmaceutical analysis to ensure the reliability of results during pharmaceutical development and routine control both in fresh and storm-cast of A. nodosum .

Mastigonemes on the anterior flagellum (AF) of flagellated Stramenopiles (which includes diverse organisms such as diatoms, brown algae, oomycetes and others) are tripartite tubular structures. We investigated the functions of mastigonemes in gametes of the brown alga Ectocarpus species 7 strain Ec32 using a mas1 mutant generated by CRISPR-Cas9. Loss of mastigonemes in the mas1 mutant gametes could be confirmed by immunofluorescence microscopy using a specific anti-MAS1 antibody and transmission electron microscopy, showing complete loss of mastigonemes from the AF. High-speed video analysis revealed a drastic reduction in swimming speed in the mas1 mutant gametes compared to wild type gametes, despite an increase in the AF beat frequency. Additionally, waveform analysis indicated larger AF double amplitudes in the mas1 mutant gametes. These results suggested that mastigonemes enhance the AF thrust. The mas1 mutant male gametes fertilized female gametes (wild type strain Ec25). A mas1 mutant female strain was established from the heterozygous sporophyte that developed from such a zygote. Both wild type and the mas1 mutant male gametes could fertilize the mas1 mutant female gametes. Mastigonemes are therefore dispensable for gamete recognition and fusion in the brown alga Ectocarpus.

Growth and survival of sea hare (Dolabella auricularia) fed with seaweeds under cage condition in Guang-guang, Mati, Davao Oriental was studied through measuring the weight of 120 samples, which ranged from 50 to 120, for three months (November 2006-January 2007). Cages were set up using (RCBD) Random Complete Block Design, four treatments with three replications: T1 control (no feeding), T2 feed with green algae (Caulerpa racemosa), T3 feed with brown algae (Sargassum polycystum), and T4 feed with red algae (Gracilaria sp.). Feeding was done weekly, and weight measurement was done every two weeks. Environmental parameters such as water temperature, pH, salinity, and turbidity were also determined every two weeks. Growth was measured by calculating the variance (S²). Survival was determined by the actual count of every individual. Data showed that growth of sea hare in T4 exhibited faster growth (0.28 gram per day fed with red algae Gracilaria sp.) compared to other treatments. Survival of sea hare ranged from 80% to 86%. Average mean temperature ranged from 31.89°C to 31.28°C, salinity ranged from 33.42 to 33.83 ppt, pH ranged from 7.93 to 7.95, and turbidity of water is very clear. During gut analysis, there were undigested parts of algae found in T4 and T2 specimens, while in T1 and T3 specimens, no remains of algae were found.

Technetium-99: Sources, transport, bioaccumulation, and trophic transfer in marine ecosystem.

Seaweed beds-driven enhancement of energy metabolism functions and their multifaceted ecological effects: A case study from Xiangyun Cove marine ranch.

Co-fermentation of probiotic lactic acid bacteria and Pichia kluyveri enhances the probiotic viability and flavor profile of enzyme-hydrolyzed kombu (Saccharina japonica) slurry.

ABSTRACT In this work, surfactant‐assisted hydrodistillation using the nonionic surfactant Triton X‐100 is reported for the first time as an extraction strategy for essential oils (EOs) from the brown alga Dictyopteris membranacea , a species well known for its rich content of bioactive metabolites, including C11 hydrocarbons (sexual pheromones), sulfur‐containing compounds, and terpenoids. A range of Triton X‐100 concentrations was evaluated to optimize the extraction process, and the results were compared to conventional hydrodistillation, which yielded 0.12%. The extraction process exhibited three distinct phases: an initial increase in yield with rising surfactant concentration; a peak yield of 0.22% (w/w) observed at a Triton X‐100 concentration of 8%–12% (v/v); and a subsequent decline at higher concentrations. EOs obtained under varying surfactant conditions were analyzed by GC‐MS and GC‐FID to assess the influence of Triton X‐100 on their chemical profile. The results have extracting demonstrated a significant impact of surfactant concentration on the relative abundance of major compound classes, notably C11 hydrocarbons, terpenes, and sulfur‐containing compounds.

Diterpenoids from the brown alga Dictyota dichotoma with nematicidal activity against the plant parasitic nematode Aphelenchoidesbesseyi.

ARGONAUTE (AGO) proteins are a highly conserved family of RNA-binding proteins that play central roles in gene regulation and developmental processes across eukaryotes. Although AGO family members have been extensively studied in animals and plants, where they are typically encoded by multiple genes, their function in brown algae, a diverse and complex group of multicellular algae, remains largely unknown. Here, we show that the genomes of several brown algae encode only a single AGO protein, containing the conserved functional domains characteristic of the family. Using the model brown alga Ectocarpus and a combination of cell biology, genetic, and transcriptomic approaches, we demonstrate that AGO is essential for the transition from vegetative growth to sexual reproductive development and for germline establishment. Our results further suggest that AGO functions in concert with microRNAs to regulate target genes primarily at the posttranscriptional level, likely through translational repression. Ectocarpus thus represents a rare example of a complex multicellular organism that relies on a single AGO protein to regulate key developmental processes, pointing to a minimalistic model of RNA-based regulation in brown algae.

Fucoxanthin, a marine carotenoid abundantly derived from brown algae, has been increasingly recognized for its broad-spectrum antitumor activities; however, its role in regulating ferroptosis remains insufficiently defined. Hypopharyngeal carcinoma is a highly aggressive head and neck malignancy with limited therapeutic options, highlighting the need for novel marine-derived anticancer agents. In this study, we investigated whether fucoxanthin induces ferroptosis in human hypopharyngeal carcinoma cells (Fadu) and elucidated the underlying molecular mechanisms. Transcriptome profiling combined with in vitro validation revealed that fucoxanthin markedly upregulated heme oxygenase−1 (HO−1), leading to increased intracellular Fe2+ levels, excessive reactive oxygen species (ROS) generation, and pronounced lipid peroxide accumulation. Fucoxanthin simultaneously reduced cysteine and glutathione (GSH) levels, disrupted mitochondrial membrane potential, and triggered ferroptotic cell death, which was significantly reversed by the ferroptosis inhibitor ferrostatin−1. Mechanistically, fucoxanthin activated the p53 pathway while suppressing SLC7A11 and GPX4, thereby impairing antioxidant defenses. Pharmacological inhibition of p53 with Pifithrin−α markedly attenuated fucoxanthin-induced cytotoxicity and ferroptosis. Together, these findings identify fucoxanthin as a promising marine-derived compound capable of inducing ferroptosis via modulation of the p53/SLC7A11/GPX4 axis, providing new insights into its potential application in hypopharyngeal carcinoma therapy.

The research aimed to identify the symbiont bacteria in brown alga Padina australis from the coastal waters of Molas, Manado city, Indonesia. Fresh samples were crushed with a mortar and pestle until smooth. A total of 1 g of the smooth alga was added into a test tube containing 9 mL of distilled water to obtain a 10-1 dilution. Next, 1 mL of a 10-1 solution was put into another test tube containing 9 mL of distilled water and vortexed for 15 minutes to obtain 10-2 dilution and so on until a 10-8 solution was obtained. 100 μL of solution from each series 10-4 – 10-8 was spread on NA media and incubated at a temperature of 27–29°C for 24 hours. DNA extraction was carried out following the modified Genomic DNA Mini Kit (Geneaid) protocol. DNA amplification was carried out using the 16S rRNA gene. Amplification using primers for the 16S rRNA gene BKXF (forward) and BKXR (reverse) resulted in fragments 1152 base pairs in length. The results of BLAST analysis of SK1 symbiont bacterial isolates found a Max score and total score of 1369, a query coverage of 97%, and a Percent Ident of 97.73%, which showed similarity to bacterial nucleotides of Bacillus cereus.

The brown alga Dictyopteris polypodioides produces a variety of sesquiterpene derivatives. However, its potential as an antimelanogenic agent remains unclear. In this study, we investigated the ability of D. polypodioides extract and its constituent compounds to inhibit melanin biosynthesis. Methanolic extracts of D. polypodioides significantly suppressed melanin accumulation in B16 melanoma 4A5 cells. We identified four sesquiterpene hydroquinone derivatives, zonarol (1), yahazunol (2), isozonarol (3), and chromazonarol (6), as active constituents. Structure-activity relationship analyses, including those of semisynthetic analogs, indicated that the hydroquinone moiety is crucial for the antimelanogenesis activity. Chromazonarol (6), which lacks a hydroquinone group, inhibits tyrosinase (monophenolase) in an uncompetitive manner, with 50% inhibitory concentration of 6.2 µm. Quantitative analysis revealed that these sesquiterpene derivatives accounted for approximately 5.6% of the dried algal biomass. D. polypodioides is a promising natural source of bioactive compounds with potential applications in preventing melanogenesis and food browning.

The pathogen-related protein 1 (PR-1) family plays an important role in plant response to biotic and abiotic stresses. PR-1 proteins have been studied in many plant species; however, they were not systematically studied in brown algae, which are important components of coastal ecosystems and have great economic value in the aquaculture industry. In the present study, we characterized the structure, evolution and expression of PR-1 proteins in brown algal genomes. A total of 141 PR-1s were identified in the 19 brown algal genomes, with an average of 7 genes in each species. Most PR-1s are acidic, while only 18 PR-1s are basic. Phylogenetic analysis showed that PR-1s in brown algae clustered into five clades, and showed no strong relationship with other lineages, suggesting an ancient origin. All the PR-1s contain a conserved CAP superfamily domain. Some PR-1s contain distinct functional domains, such as the WSC, Blect, and Bulb-type lectin domains, which are involved in carbohydrate binding. Their promoter regions were enriched in stress-response elements, hormone-response elements, growth and development elements. GO and KEGG annotation showed that brown algal PR-1 proteins may be involved in diverse roles and pathways. Moreover, expression analysis shows that some PR-1s, especially basic proteins are responsive to abiotic stress conditions and life stage development, further suggesting they participate in multiple functional pathways. Our results provide important data for future research on the function of brown algal PR-1 family genes.

Abstract Fermented foods are increasingly in-demand for their health-promoting properties and extended shelf-life. Seaweeds, abundant in minerals, vitamins, and bioactive metabolites, represent an underexplored resource for functional food development. In this study, two edible Scottish brown seaweeds (Alaria esculenta and Laminaria digitata) were subjected to lactic acid fermentation. Microbiological and physicochemical analyses confirmed successful fermentation, marked by a pH reduction from 6.0 to 4.5, lactic acid accumulation with the dominance of lactic acid bacteria, while the incidence of foodborne pathogens remained undetected. Metabolomic profiling by 1H-NMR and LC-HRMS revealed specific chemical changes, including the production of oxygenated unsaturated lipids and loliolide, compounds potentially linked to stress and defense responses. Functional analysis highlighted enrichment of essential unsaturated fatty acid metabolism pathways, particularly in L. digitata. Biological assays demonstrated that fermented seaweed extracts inhibited biofilm formation of methicillin-resistant Staphylococcus aureus (MRSA), with enhanced effects observed for fermented L. digitata. Together, these findings demonstrate the feasibility of lactic acid fermentation to valorise edible seaweeds into safe, metabolite-enriched functional foods with potential health benefits.

The skeletal muscle system is particularly susceptible to degenerative and inflammatory processes that threaten mobility, quality of life, and systemic health. Marine plants, including brown, red, and green algae, are valuable yet understudied sources of bioactive compounds with therapeutic potential against skeletal muscle inflammation and degeneration. This narrative review provides the first overview of polyphenols, polysaccharides, carotenoids, and multiminerals derived from marine plants, with a particular focus on their effects on skeletal muscle, bone, and joint tissues. It highlights both the therapeutic potential and the limitations of marine plant-derived bioactive compounds in the musculoskeletal system. The compounds discussed, such as phlorotannins, ulvan, fucoidan, carotenoids, spirulina derivatives, and Aquamin, modulate key signaling pathways, including NF-κB, JAK/STAT3, and the NLRP3 inflammasome. Among these, MAPK emerges as the most consistently affected axis across all compound classes, leading to a reduction in TNF-α, IL-1β, IL-6, and oxidative stress markers. These bioactive compounds have been shown in both in vitro and in vivo models to reduce muscle catabolism, enhance osteoblast differentiation and mineralization, and reduce cartilage inflammation. Despite favorable safety, biocompatibility, and biodegradability profiles, current evidence shows that systemic applications significantly dominate over local delivery, highlighting the untapped potential of localized delivery strategies. Overall, this narrative review underscores the growing importance of marine plant-derived bioactives as promising natural agents for maintaining musculoskeletal integrity and alleviating degenerative disorders.

Background/Objectives: The rise in antimicrobial resistance is one of the major challenges to global health systems, which necessitates the development of new antibacterial compounds. The bioactive compounds of brown seaweed Sargassum duplicatum have demonstrated potential antibacterial activity. This study applied metabolomic profiling and molecular networking in combination with antibacterial screening assays to assess the antimicrobial properties of S. duplicatum extracts against multidrug-resistant bacteria. Methods: Two extraction methods, i.e., maceration and microwave extraction, were used. Therewith, untargeted metabolomic profiling was performed using Liquid Chromatography-High Resolution Mass Spectrometry (LC-HRMS). Molecular networks (MNs) were established and compound dereplication was conducted using the spectral database of the Global Natural Products Social Molecular Networking platform (GNPS). Additionally, antimicrobial assays were conducted against Gram-positive and Gram-negative bacterial strains, including multidrug-resistant bacteria, i.e., methicillin-resistant Staphyloccocus aureus ATCC 33592 (MRSA) and β-lactamase, producing Escherichia coli ATCC 35218 (TEM-1 positive strain). Result: Dereplication resulted in the prediction of six compounds with reported antimicrobial properties, i.e., 13-docosenamide, 9-octadecenamide, pheophorbide A, ouabain, sarmentoside B and AC1L1X1Z. Antibacterial screening of the extracts revealed that the ethyl acetate maceration extracts exhibited the strongest inhibitory activity, with inhibition values between 85 and 98% against S. aureus ATCC 33592. Conclusions: This metabolomics study requires further research to isolate, purify, confirm, and validate the dereplicated compounds that may have potential antibacterial activity.

Brown seaweeds are marine bioresources rich in bioactive compounds such as carbohydrates, proteins, pigments, fatty acids, polyphenols, vitamins, and minerals. Among these substances, brown algae-derived polysaccharides (alginate, fucoidan, and laminarin) have promising industrial prospects owing to their distinctive structural features and diverse biological activities. Consequently, processing technologies have advanced substantially to address industrial requirements for biopolymer quality, cost-effectiveness, and sustainability. Over the years, significant progress has been made in developing various advanced methods for the sake of extracting, purifying, and structurally characterizing polysaccharides. Aside from that, numerous studies reported their broad spectrum of biological activities, such as antioxidant, anti-inflammatory, anticoagulant, and antimicrobial properties. Furthermore, these substances have various industrial, pharmaceutical, bioenergy, food, and other biotechnology applications. The present review systematically outlines the brown algae-derived polysaccharides treatment process, covering the entire value chain from seaweed harvesting to advanced extraction methods, while highlighting their biological activities and industrial potential as well.

Fucoidan, a complex sulfated polysaccharide derived from marine brown seaweeds, exhibits broad biological activities, including anticoagulant, antitumor, antiviral, anti-inflammatory and lipid-lowering effects. Fucoidan confers neuroprotection in animal models of a broad spectrum of brain disorders such as Parkinson’s disease (PD) and depression. However, the effect of fucoidan on gut-derived neuroinflammation and associated behavioral changes has been scarcely investigated. In comparison to fucoidan from other brown seaweeds, that from Fucus vesiculosus exhibited a better neuroprotective effect in vivo and more potent radical scavenging activity in vitro. Fucoidan from Laminaria japonica ameliorates behavioral disorders related to acute ulcerative colitis (UC) in aged mice. It is of interest to assess the effects of fucoidan administration on intestinal and brain inflammation in the acute colitis mouse model. Fucoidan treatment ameliorated DSS-induced intestinal pathology, reduced the inflammatory mediator expression in the gut and brain, and activated intestinal macrophages and cortical microglia in the UC mice. It also protected the intestinal mucosal barrier and blood–brain barrier as well as prevented neuronal damage, while alleviating anxiety-like behavior in UC mice. These results suggest fucoidan supplementation may help prevent brain disorders, such as depression and PD, potentially involving gut–brain axis-related mechanisms, as fucoidan suppresses gut-derived neuroinflammation.

Eutrophication of freshwater and saltwater is a natural phenomenon that is currently exacerbated by human activities, resulting in increased nutrient concentrations, especially nitrogen and phosphorus. This study reveals that observations indicate a decline in biodiversity in Lake Santa Maria Tasi Tolu Dili, which is in line with the deterioration of ecological conditions and the destruction of its habitat. This study aims to explore indicators of eutrophication in Lake Santa Maria, specifically focusing on human activities and their impacts on environmental pollution, eutrophication, and algal blooms in freshwater lakes, saltwater lakes, and rivers. The main objective of this study is to explain the mechanism of eutrophication and identify factors contributing to algal blooms in Lake Santa Maria waters. In addition, this study will discuss the relationship between eutrophication and algal blooms, as well as the consequences of environmental pollution in lake water. Qualitative methodology, as described by Oranga and Matere (2023), involves an in-depth analysis of specific cases within a broader category of phenomena, which are generally referred to as case studies. While this approach may not yield universally applicable insights, it can be a valuable tool in the early stages of research, facilitating the development of hypotheses that can be rigorously tested with a larger sample size. As highlighted by Hunter et al. (2019), this research adopted an exploratory approach to data collection, which included direct field data collection or primary data generation to gain a deeper understanding of a particular subject, phenomenon, or issue. The findings of this investigation reveal that the eutrophication of Lake Santa Maria is influenced by a variety of factors. Lake Santa Maria is predominantly characterized by the presence of green, red, brown, and golden algae, as well as various macrophytes. These algal species create floating colonies within the lake, while others are situated along the shores, coexisting with macrophytes. They flourish within a temperature range of 25°C to 32°C and have demonstrated adaptability to a pH range of 7.12 to 7.43, along with salinity levels between 14‰ and 15‰. Notably, there is evidence of eutrophication occurring in the lake's waters. The cyanobacterial species identified include Anabaena, Oscillatoria, Nodularia, Nostoc, and Microcystis aeruginosa. The effects of eutrophication and drought on the lake's biotic community are profound, particularly due to elevated evaporation rates resulting from daily high temperatures and dry winds, which further exacerbate fish mortality alongside lake pollution. To avert further degradation of the lake's water quality, it is essential to implement clear regulations and provide comprehensive information to the surrounding community.

Brown algae of the Cystoseira genus are recognized as valuable sources of bioactive compounds, including polysaccharides. Within the framework of current restoration efforts regarding damaged Ericaria amentacea populations in the Mediterranean Sea, the valorization of apices derived from ex situ cultivation waste represents a sustainable opportunity for industrial and biomedical applications. In this study, sodium alginate (SA) was extracted from E. amentacea apex by-products using a hydrothermal–alkaline method and subsequently chemically characterized. FTIR analysis showed O-H, C-H, and COO- stretching compatible with commercial alginates, while 1H-NMR spectroscopy indicated high β-D-mannuronic acid content, with an M/G ratio of 2.33. The extracted SA displayed a molecular weight of 1 × 104 g/mol and a polydispersity index of 3.5. The bioactive properties of the SA extract were investigated in chemico and in vitro. SA exhibited remarkable antioxidant activity, showing significant DPPH and nitric oxide-radical-scavenging capacity. Furthermore, SA demonstrated a strong anti-inflammatory effect in LPS-stimulated macrophages through modulation of several inflammatory mediators (i.e., IL-6, IL-8/CXCL5, MCP-1, and TNF-α). In particular, SA promoted a striking iNOS gene expression inhibition, which, paired with its direct NO-scavenging ability, paves the way for future pharmacological use of E. amentacea derivatives, particularly if sustainably obtained from restoration activity waste.