Sargassum Fusiforme Research Articles

Survey of arsenic content in edible seaweeds and their health risk assessment

Since humans are especially sensitive to arsenic exposure, predominantly through diet, a strict control of the most widely consumed seaweeds is mandatory. Total arsenic contents and arsenic species in twenty-five different seaweeds from five different origins were studied. Seaweeds selected, included Phaeophyta (brown seaweed), Chlorophyta (green seaweed) and Rhodophyta (red seaweed) genera. The highest arsenic content appears in the Phaeophyta seaweed in the range from 11 to 162 mg kg−1 dried weight. Arsenosugars were found to be the predominant species of arsenic in most seaweeds, being up to 99.7% of total arsenic in some samples. The arsenic dietary intakes for seaweeds studied were assessed and the Target Hazard Quotients (THQ) and the Target Cancer Risk (TCR) were calculated, taking into account inorganic arsenic contents (iAs). iAs species in seaweeds showed low risk of arsenic intake except for Hizikia fusiforme samples.

In vitro and in vivo anti-inflammatory properties of an active fucoidan fraction from Sargassum fusiforme and a fraction-based hydrogel

In a previous study, we separated an active fucoidan (JHCF4) from acid-processed Sargassum fusiforme, then analyzed and confirmed its structure. In the present study, we investigated the potential anti-inflammatory properties of JHCF4 and a JHCF4-based hydrogel in vitro and in vivo. JHCF4 reliably inhibited nitric oxide (NO) production in LPS-induced RAW 264.7 macrophages, with an IC50 of 22.35 μg/ml. Furthermore, JHCF4 attenuated the secretion of prostaglandin E2, tumor necrosis factor-α, interleukin (IL)-1β, and IL-6, indicating that JHCF4 regulates inflammatory reactions. In addition, JHCF4 downregulated iNOS and COX-2 and inhibited the activation of the MAPK pathway. According to further in vivo analyses, JHCF4 significantly reduced the generation of reactive oxygen species (ROS), NO production, and cell death in an LPS-induced zebrafish model, suggesting that JHCF4 exhibits anti-inflammatory effects. Additionally, a JHCF4-based hydrogel was developed, and its properties were evaluated. The hydrogel significantly decreased inflammatory and nociceptive responses in carrageenan (carr)-induced mouse paws by reducing the increase in paw thickness and decreasing neutrophil infiltration in the basal and subcutaneous layers of the toe epidermis. These results indicate that JHCF4 exhibits potential anti-inflammatory activity in vitro and in vivo and that JHCF4-based hydrogels have application prospects in the cosmetic and pharmaceutical fields.

Therapeutic potential of seaweed extracts: In vitro and in vivo studies on alleviating inflammation and enhancing intestinal barrier function.

Rich in diverse compounds such as polysaccharides, pigments, and phenols, seaweed offers not only nutritional benefits but also functional elements such as fucoidan, which demonstrates anticoagulant, anticancer, and anti-inflammatory properties. This investigation screened 22 seaweed extracts obtained using either water or ethanol as solvents from a total of fourteen seaweed species to evaluate their potential as dietary supplement ingredients. In inflammation-induced Caco-2 cell models, Saccharina japonica, Capsosiphon fulvescens, Hizikia fusiforme, and Chondrus ocellatus exhibited a significant increase in TEER values 24 h after treatment with seaweed extracts, in contrast to the cocktail group (p < 0.05). Additionally, permeability significantly decreased compared to the cocktail group (p < 0.05). Notably, these species exhibited a reduction in mRNA expression of TNF-alpha and iNOS, coupled with an elevation in the protein expression of tight junction proteins. Moreover, when tested in DSS-induced mice, these seaweeds demonstrated enhancements in colon health indices, suggesting their potential as beneficial treatments for inflammatory bowel diseases and associated conditions. This study demonstrates the therapeutic promise of these four seaweed species and emphasizes their prospective role in treating inflammatory bowel diseases, urging further exploration of their therapeutic mechanisms and clinical applications.

Immune-Enhancing Effects of Marine Algae Extracts: Modulation of Macrophage Activation by Sargassum horneri, Sargassum fusiforme, and Undaria pinnatifida

The immune system acts as a defense mechanism against foreign antigens. Impairment of the immune system leads to the development of chronic diseases such as respiratory infections, cancer, cardiovascular diseases, and neurodegeneration. Macrophages, natural scavengers that are part of innate immunity, are known to directly participate in scavenging foreign antigens. The functional modulation of macrophages could be an effective treatment for pathogens. Seaweeds are marine macroalgae known to exhibit multiple bioactive properties. Thus, this study evaluated the immune-enhancing properties of marine brown algae extracts of Sargassum horneri (SH), Undaria pinnatifida (UP), and Sargassum fusiforme (SF) on murine macrophage cells. The results showed that all three algal extracts stimulated cell proliferation. SH and UP outshined SF in enhancing the expression levels of IL-1β, TNF-α, and IL-6 at almost all the concentrations tested as compared to SF which showed similar effects only at 200 or 400 μg/mL. A similar trend was seen in TNF-α, NO, and PGE2 production. Additionally, only SH and SF could enhance the mRNA expression levels of IL-12, and only SH upregulated the mRNA expression level of IL-10. The algal extracts also enhanced the phagocytosis activity of macrophages at 50–400 μg/mL for SH and 100–400 μg/mL for UP and SF. In conclusion, we found that these algal extracts could be considered immunomodulators that enhance the functional activity of macrophages.

Integrated biorefinery approach for seaweed Sargassum fusiforme: A step towards green circular economy

This study aims to maximize the utilization of Sargassum fusiforme (SF), embedding the concept of a green circular economy. We developed a green extraction process using water and ultrasound assistance to extract high-value SF polysaccharides (SFPS). A 2k factorial design coupled with center points evaluated the curvature effect in the extraction process. Optimal extraction conditions were identified to be a mass-liquid ratio of 1:59 (w/v), an extraction temperature of 70 °C and time of 88 min, yielding 15.30 wt% SFPS, validated through experiments. SFPS demonstrated significant antioxidant capacity, indicated by their ferric ion reduction ability and superoxide anion scavenging ability. Post-extraction, the waste ethanol solution and SF residue were employed as feedstock for hydrothermal liquefaction (HTL), aiming to produce biocrude oil. We explored various parameters affecting the yield and quality of the resultant biocrude. The optimal HTL conditions for SF residue included a temperature of 280 °C and a reaction time of 45 min. The biocrude obtained using the waste solution exhibited higher carbon content (69.83%) and higher heating value (33.42 MJ/kg) compared to freshwater, indicating enhanced energy recovery (87.65% vs. 15.39%). Also, the presence of ethanol in waste solution facilitated a decrease in fatty acid content from 48.50% to 24.50%, while simultaneously increasing ester content from 6.37% to 35.54%, presumably due to the trans-esterification of fatty acids into esters. Utilizing the waste ethanol solution as HTL processing medium also led to a much lower greenhouse gas emissions (1714.0 kg CO2-eq) compared to that of freshwater (7735.4 kg CO2-eq) as evidenced by the life cycle assessment. This study's innovative approach not only valorizes the waste streams from SFPS extraction but also adds value by generating high-quality biocrude oil, offering practical solutions for waste reduction and resource recovery, fostering sustainable development and circular economy initiatives.

Effects of temperature and irradiance on the growth of regenerated juveniles from Sargassum fusiforme holdfasts

ABSTRACT To improve the quality of Sargassum fusiforme seedlings, suitable strains of juveniles regenerated from holdfasts need to be bred. In this study, effects of different temperatures (16, 20, and 24 °C) and irradiances (100, 120, and 160 µmol photons·m−2·s−1) on the growth of juveniles (new individuals) from the holdfasts of S. fusiforme were investigated to provide strategies for the cultivation of vegetative propagation seedlings of S. fusiforme. The results demonstrated that during cultivation at 24 °C, the regenerated juveniles rotted after twenty-one days, and their relative growth rate, photosynthetic activity and pigment content decreased substantially. The low temperature of 16 °C also decreased their photosynthetic activity and growth considerably. At a high irradiance of 160 µmol photons·m−2·s−1, the growth rate and photosynthetic activity decreased. Under conditions of 20 °C and 120 µmol photons·m−2·s−1, juveniles showed higher photosynthetic activity and nitrate uptake rates, which increased the growth of the juveniles and lateral branches and promoted the accumulation of photosynthetic pigment. Therefore, culture conditions of 20 °C and 120 µmol photons·m−2·s−1 can be applied for early indoor cultivation of regenerated juveniles of S. fusiforme. This study provided technical support for solving the problem of single provenance of S. fusiforme seedlings.

NIRS prediction of the protein, fat, and ash of Sargassum fusiforme at different growth stages: A quality control approach

Seaweed is a sustainable source of nutrients for human consumption, and a rapid and accurate quality control approach is essential for ensuring the nutritional value and health benefits of seaweed. The nutritional constituents and quality of seaweed vary significantly along with their growth stages. The present study developed a quality control approach for seaweed Sargassum fusiforme, rapid and convenient, using near-infrared spectroscopy (NIRS) and chemometrics to predict protein, fat, and ash in S. fusiforme at different growth stages. Partial least squares (PLS) regression was utilized to construct the quantitative relationship between NIR spectral data and nutritional components. Moreover, three wavelength selection algorithms, namely, competitive adaptive reweighted sampling (CARS), genetic algorithm, backward interval (BI) and synergy interval, were implemented to optimize the PLS models and improve prediction accuracy. Results demonstrated that the CARS-PLS model exhibited superior performance with a root mean square error of prediction and a coefficient of determination of prediction of 0.1075 % and 0.9936 for protein, 0.1807 % and 0.7706 for fat, and 0.3315 % and 0.9937 for ash, respectively. The effects of different developmental stages on the nutritional quality of S. fusiforme were also investigated. The seedling and early growth stages were the preferable harvest times for preparing high-protein foods and health supplements. The overall results confirmed the strong applicability of NIRS as a rapid and accurate method for measuring the protein, fat, and ash contents of S. fusiforme. This work also recommended that S. fusiforme quality can be controlled in a more precise and refined manner on the basis of a customer-oriented strategy.

Dynamics of microbial communities, flavor, and physicochemical properties of kombucha-fermented Sargassum fusiforme beverage during fermentation

In this study, a novel kombucha-fermented Sargassum fusiforme beverage was prepared, and physicochemical properties, volatile flavor compounds, and microbial communities during the beverage fermentation were investigated. The results indicated that after fermentation, the pH decreased to 2.77 ± 0.05, titratable acid content increased to 4.42 ± 0.20 mg/mL, organic acids content increased and acetic acid became the main organic acid, values for total sugar content decreased and the reducing sugar content increased during fermentation. The clearance rates of DPPH radicals, hydroxyl radicals, superoxide anion radicals, and ABTS radicals increased after fermentation. In addition, the results of high-throughput sequencing showed that Zygosaccharomyces was the main fungi, and Komagataeibacter and Acetobacter were the main genera of bacteria in kombucha-fermented S. fusiforme beverage. Gas chromatography-ion migration spectrometry results showed that ethanol, acetic acid, acetone, and ethyl acetate were the main volatile flavor compounds. The correlation results between the dominant microbial community and the major volatile flavor compounds indicated that Pichia, Aspergillus, Zygosaccharomyces, Acetobacter, and Ralstonia had a positive effect on the flavor formation of beverages, which provided the direction for the later development and accurate screening of flavorous functional microorganisms.

Immunomodulation by extracellular vesicle-like nanoparticles from marine macroalgae Sargassum fusiforme: Enhancing Type 1 T helper and cytotoxic T lymphocyte-mediated immune responses

This study investigated the immunological features and therapeutic potential of extracellular vesicle-like nanoparticles isolated from the marine macroalgae Sargassum fusiforme (SF-NPs). SF-NPs were approximately 266.4 nm in size, and comprehensive metabolomic analysis revealed 38 metabolites. SF-NPs can upregulate dendritic cell (DC) maturation markers, increase pro-inflammatory cytokine production, and enhance antigen presentation capacity. DC maturation is regulated by the mitogen-activated protein kinase and nuclear factor-kappa B pathways. Notably, SF-NPs-primed DCs orchestrated robust CD4+ and CD8+ T-cell proliferation, fostering potent Type 1 T-helper(Th1) responses and cytotoxic T lymphocyte (CTL) activity. In a cyclophosphamide-induced immunosuppression mouse model, SF-NPs restored and activated immune cell populations, including DCs, natural killer, CD4+ T, and CD8+ T cells. SF-NPs reversed cyclophosphamide-induced Type 2 T-helperand regulatory T cell-biased responses, favoring Th1 and CTL responses, including multifunctional T cell responses. This study highlighted the potential of SF-NPs as therapeutic candidates for diseases requiring Th1 and CTL responses.

Fucoidan isolated from the edible seaweed Sargassum fusiforme suppresses skin damage stimulated by airborne particulate matter

Particulate matter (PM) pollution is a major environmental factor to global health problems. It exposes to the skin of human body, induces skin diseases and aging. Sargassum fusiforme is rich in a variety of bioactive substances and possesses the potential to protect skin against PM-stimulated damage. The purpose of this study is to investigate the effect of the fucoidan (SF-F4) isolated from S. fusiforme on PM-stimulated skin damage in human keratinocytes (HaCaT cells) and human dermal fibroblasts (HDF cells). The results show that PM significantly increased ROS level and promoted the cell death in both HaCaT cells and HDF cells. However, SF-F4 effectively increased the viability of PM-treated HaCaT cells by inhibiting apoptosis via scavenging intracellular ROS. In addition, SF-F4 regulated the expressions of MMPs and pro-inflammatory molecules in PM-stimulated HDF cells in a concentration-dependent manner, thus, it increasing pro-collagen content of PM-stimulated HDF cells. In conclusion, the current findings indicate that SF-F4 can effective inhibit PM-induced oxidative stress and reduce the secretion of pro-inflammatory factors and MMPs in cells, thereby slowing down the triggering of skin damage, suggesting that SF-F4 may be a potential pharmaceutical or cosmetic ingredient.

Effects and Mechanisms of Fucoxanthin from Hizikia fusiforme on Inhibiting Tongue Squamous Cell Carcinoma Proliferation via AKT/mTOR-Mediated Glycolysis

Fucoxanthin, a natural carotenoid, contains special ene bonds and 5, 6-mono-epoxide compounds in its molecule, which has physiological activities such as anticancer, antioxidant, anti-inflammatory, antiobesity, and antidiabetic. However, the anticancer actions and underlying mechanisms of fucoxanthin on oral cancer remain to be assessed. In this study, we used tongue carcinoma (CAL-27) cells to examine the effects and underlying mechanisms of fucoxanthin derived from Hizikia fusiforme on CAL-27 proliferation. MTT assays were used to estimate fucoxanthin’s effect on the proliferative capacity of CAL-27 cells. Flow cytometry was used to examine how fucoxanthin affects apoptosis initiation and alters cell cycle progression in CAL-27 cells. Spectrophotometry was used to assess the impact of fucoxanthin on adenosine triphosphate (ATP) generation, glucose uptake, lactate production, and the enzymatic activities of pyruvate kinase and hexokinase in CAL-27 cells. Western blotting was used to investigate fucoxanthin’s impact on the protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway and glycolysis-related protein expression levels in CAL-27 cells. Fucoxanthin significantly inhibited CAL-27 cell viability time- and dose-dependently p &lt; 0.01 . Administration of fucoxanthin induced CAL-27 cell apoptosis and cell cycle arrest at the G1 phase p &lt; 0.05 . Furthermore, fucoxanthin significantly decreased glucose uptake, lactate production, and ATP production in CAL-27 cells p &lt; 0.01 and significantly inhibited glycolysis-related enzyme activities and protein expression levels p &lt; 0.05 . Fucoxanthin also substantially decreased the expression levels of phosphorylated ribosomal protein S6, phosphorylated AKT, and phosphorylated mTOR p &lt; 0.05 . In conclusion, fucoxanthin inhibited CAL-27 cell proliferation, and this mechanism may be associated with the AKT/mTOR-mediated glycolysis pathway.

Bioactivities of the Popular Edible Brown Seaweed Sargassum fusiforme: A Review.

Sargassum fusiforme has a wide range of active constituents (such as polysaccharides, sterols, polyphenols, terpenes, amino acids, trace elements, etc.) and is an economically important brown algae with a long history. In recent years, S. fusiforme has been intensively studied and has attracted wide attention in the fields of agriculture, environment, medicine, and functional food. In this review, we reviewed the current research status of S. fusiforme at home and abroad over the past decade by searching Web of science, Google Scholar, and other databases, and structurally analyzed the active components of S. fusiforme, and on this basis, we focused on summarizing the cutting-edge research and scientific issues on the role of various active substances in S. fusiforme in exerting antioxidant, anti-inflammatory, antitumor, antidiabetic, immunomodulatory, antiviral antibacterial, and anticoagulant effects. The mechanisms by which different substances exert active effects were further summarized by exploring different experimental models and are shown visually. It provides a reference to promote further development and comprehensive utilization of S. fusiforme resources.

Antioxidant and Anti-Aging Properties of Polyphenol-Polysaccharide Complex Extract from Hizikia fusiforme.

Hizikia fusiforme has a long history of consumption and medicinal use in China. It has been found that natural plants containing polyphenol-polysaccharide complexes have better activity compared with polyphenols and polysaccharides. Therefore, in this study on enzymatic hydrolysis and fractional alcohol precipitation, two kinds of polyphenol-polysaccharide complexes (PPC), PPC1 and PPC2, were initially obtained from Hizikia fusiforme, while the dephenolization of PPC1 and PPC2 produced PPC3 and PPC4. Through in vitro assays, PPC2 and PPC4 were found to have higher antioxidant activity, and thus were selected for testing the PPCs' anti-aging activity in a subsequent in vivo experiment with D-gal-induced aging in mice. The results indicated that PPCs could regulate the expressions of antioxidant enzymes and products of oxidation, elevate the expressions of genes and proteins related to the Nrf2 pathway in the mouse brain, enrich the gut microbiota species and increase the Bacteroidota-Firmicute (B/F) ratio. Above all, the Hizikia fusiforme polyphenol-polysaccharide complex has potential in the development of natural anti-aging drugs.

Molecular docking and antibacterial activity of Sargassum fusiforme extracts against major coral pathogens.

The present study evaluates the antibacterial properties of alkaloids and the crude extracts (ethanol, n-hexane and ethyl acetate) from seaweed Sargassum fusiforme against coral pathogens (Photobacterium galatheae, Vibrio harveyi, Bordetella trematum,and Ochrobactrum pseudogrignonese) isolated from coral Porites lutea. To our knowledge, this is the first in vitro assay for such extracts on Porites lutea coral pathogens. Bacterial pathogens have been identified using 16S RNA and BankIt into gene bank and given the accession numbers (OR401000; OR401001; OR401336, and OR400998 respectively). GC-Mass profiling conducted for n-hexane compounds confirmed the presence of thirty-eight molecules, twelve of which have been previously reported for their bioactivity. The results revealed that alkaloids and n-hexane extract demonstrated eminent antibacterial activity compared to the other extracts against the tested coral pathogenic bacteria. Molecular docking was conducted to evaluate the twelve previously mentioned bioactive molecules to get a full understanding of the interaction of those bioactive molecules on vital bacterial proteins (Hemolysin protein (PDB ID: 1XEZ) and Cytoplasmic proteins (PDB ID: 3TZC)). Docked twelve molecules against hemolysin protein (PDB ID: 1XEZ) came exactly in line with the docked result of the same molecules with cytoplasmic proteins (PDB ID: 3TZC), proving the bioactivity of 6-O-Palmitoyl-L-ascorbic acid, 3TMS derivative; Glycerol monostearate, 2TMS derivative and Eicosanoic acid complexes in antibacterial activity action and score higher than reference ligand. Those three compounds will be investigated separately in future in vitro assay soon. Our conclusions align with the study's antibacterial in vitro assay results. The present study reports the novelty of different extracts of S. fusiforme as an antibacterial agent against coral pathogenic bacteria that trigger diseases in Porites lutea.

Physicochemical Properties and Biological Characteristics of Sargassum fusiforme Polysaccharides Prepared through Fermentation of Lactobacillus

Sargassum fusiforme polysaccharides (SFPs) have multiple activities. The fermentation of S. fusiforme by Lactobacillus can alter its polysaccharide properties and biological activities. In this study, three different Lactobacillus species (Lactobacillus plantarum (LP), Lactobacillus acidophilus (LA), and Lactobacillus rhamnosus (LR)) were selected to ferment S. fusiforme. The polysaccharides SFP (unfermented) and FSFP (fermented by LP, LA, or LR denoted as LP-SFP, LA-SFP, and LR-SFP, respectively) were extracted, and their physicochemical properties and biological activities were investigated. According to the results, fermentation caused significant changes in the physicochemical properties and biological activities of SFP. Specifically, FSFP showed a significant increase in uronic acid and fucose content and a significant decrease in molecular weight; LA-SFP and LR-SFP had stronger DPPH scavenging abilities; LR-SFP had the strongest inhibition of ROS production and cell mortality; LP-SFP and LR-SFP significantly increased SOD activity in zebrafish; LA-SFP had a significant effect on the proliferation of Lactobacillus plantarum; LP-SFP had a significant effect on the proliferation of Lactobacillus rhamnosus; and LA-SFP had a stronger food-excretion-promoting activity. In conclusion, the fermentation of Lactobacillus for the preparation of SFPs can change the physicochemical properties of polysaccharides and has broad potential for improving their biological activity.

Effects of foods and food components on the in vitro bioaccessibility of total arsenic and arsenic species from Hizikia fusiforme seaweed

Seaweed is an important food source, especially in many Asian countries, because of its high nutritional value; however, increasing arsenic (As) accumulation may pose serious hazards to human health. The influence of food components on As bioaccessibility and transformation in the high As-containing seaweed Hizikia fusiforme was determined using an in vitro gastrointestinal digestion method. The results showed that co-digestion with several daily foods (such as celery, broccoli, onion, green chili, tomato) produced a higher As bioaccessibility (approximately 6–11 % increase) compared with that of seaweed alone. Vegetables such as fennel (Foeniculum valgare Mill.), celery (Apium grareolens L.), blanched garlic leaves (Allium sativum L.), scallions (Allium fistulosum L.), ginger (Zingiber officinale Rosc.), and green pepper (Capsicum frutescens L. vat. grussum Bailey) decreased bioaccessible inorganic As (18–35 %) in both the gastric and small intestinal phases. Meanwhile, the process of reducing As(V) to As(III) also occurred during co-digestion with some food matrices. Egg white and other animal proteins were the most effective reducing agents, transforming >70 % As(V) into As(III) in the solution system. These results may have important implications for health risk assessment via co-consumption. The present study provides the first evidence showing that the co-consumption of some vegetables and proteins leads to a higher toxicity of inorganic arsenic-containing food. In addition, the positive and negative effects of co-digestion on the bioaccessibility of essential metals (iron, manganese) compared to single digestion were evaluated in this study.

Hypolipidemic Activity and Mechanism of Action of Sargassum fusiforme Polysaccharides.

Sargassum fusiforme polysaccharide (SFP) is a kind of biologically active macromolecule with biological functions. In this study, oxidative stress and high-fat HepG2 cell models were established to investigate its lipid-lowering activity and mechanism of action. It was found that SFP and its two isolated fractions had antioxidant effects on the cells. It was also found the polysaccharides decreased the content of total cholesterol and total triglyceride in the high-fat cells. RT-qPCR assays revealed that the three polysaccharides down-regulated the mRNA expression level of ACC, PPARγ, and SREBP-2. It could be concluded that the hypolipidemic effect of SFPs is achieved via multiple pathways, including the regulation on the expression level of lipid metabolism-related key enzymes and factors, and binding with bile acids. The hypolipidemic effect of SFPs could be partially due to their antioxidant activity. SFPs developed in the present work have potential as ingredients of functional foods with hypolipidemic effect.

Growth promotion of Sargassum fusiforme by epiphytic microbes is dependent on the extent of interspecific interactions of the microbial community

Profound growth differences such as seedling length and biomass are often observed during the cultivation of Sargassum fusiforme despite the absence of detectable variance in abiotic factors that could have affected this process. This highlights the importance of biotic factors such as epiphytic microbiota in controlling seedling growth. Yet, how, and to what extent microbial activities can affect host growth in the presence of seawater flow and continuous erosion remains debatable. Particularly, the contribution of microbial network interactions to the growth of macroalgae remains poorly understood. This study aimed to compare the physicochemical properties of S. fusiforme seedlings via 16S rRNA gene Illumina sequencing-based profiling of the epiphytic microbial communities of seedlings with different lengths. Significantly different epiphytic bacterial communities were observed among S. fusiforme seedlings of different lengths. The result showed that community from longer seedlings maintained higher bacterial diversity with the taxa Gammaproteobacteria, Burkholderiales, Alteromonadales, Vibrionaceae, Ralstonia, Colwelliaceae, and Thalassotalea being selectively enriched. More importantly, microbial interspecific interactions, which were predominantly positive, were enhanced consistently in communities of the longer seedlings, indicative of reinforced prevalent and mutually cooperative relationships among the microorganisms associated with S. fusiforme seedlings of greater length. Furthermore, longer seedlings also displayed up-regulation of microbial functional potentials involved in N fixation and mineralization, P mineralization and transportation, and ion transportation compared with shorter ones. Lastly, stochastic processes dominated the community assembly of the epiphytic microorganisms. These findings could provide new insights into the relationship between microbial communities and growth in S. fusiforme seedlings and enable us to predict the community diversity and assembly of macroalgae-associated microbial communities. This could have important implications for linking microbial community diversity and network interactions to their host productivity.

Activation of Liver X Receptors and Peroxisome Proliferator-Activated Receptors by Lipid Extracts of Brown Seaweeds: A Potential Application in Alzheimer's Disease?

The nuclear liver X receptors (LXRα/β) and peroxisome proliferator-activated receptors (PPARα/γ) are involved in the regulation of multiple biological processes, including lipid metabolism and inflammation. The activation of these receptors has been found to have neuroprotective effects, making them interesting therapeutic targets for neurodegenerative disorders such as Alzheimer's Disease (AD). The Asian brown seaweed Sargassum fusiforme contains both LXR-activating (oxy)phytosterols and PPAR-activating fatty acids. We have previously shown that dietary supplementation with lipid extracts of Sargassum fusiforme prevents disease progression in a mouse model of AD, without inducing adverse effects associated with synthetic pan-LXR agonists. We now determined the LXRα/β- and PPARα/γ-activating capacity of lipid extracts of six European brown seaweed species (Alaria esculenta, Ascophyllum nodosum, Fucus vesiculosus, Himanthalia elongata, Saccharina latissima, and Sargassum muticum) and the Asian seaweed Sargassum fusiforme using a dual luciferase reporter assay. We analyzed the sterol and fatty acid profiles of the extracts by GC-MS and UPLC MS/MS, respectively, and determined their effects on the expression of LXR and PPAR target genes in several cell lines using quantitative PCR. All extracts were found to activate LXRs, with the Himanthalia elongata extract showing the most pronounced efficacy, comparable to Sargassum fusiforme, for LXR activation and transcriptional regulation of LXR-target genes. Extracts of Alaria esculenta, Fucus vesiculosus, and Saccharina latissima showed the highest capacity to activate PPARα, while extracts of Alaria esculenta, Ascophyllum nodosum, Fucus vesiculosus, and Sargassum muticum showed the highest capacity to activate PPARγ, comparable to Sargassum fusiforme extract. In CCF-STTG1 astrocytoma cells, all extracts induced expression of cholesterol efflux genes (ABCG1, ABCA1, and APOE) and suppressed expression of cholesterol and fatty acid synthesis genes (DHCR7, DHCR24, HMGCR and SREBF2, and SREBF1, ACACA, SCD1 and FASN, respectively). Our data show that lipophilic fractions of European brown seaweeds activate LXRs and PPARs and thereby modulate lipid metabolism. These results support the potential of brown seaweeds in the prevention and/or treatment of neurodegenerative diseases and possibly cardiometabolic and inflammatory diseases via concurrent activation of LXRs and PPARs.

Polysaccharide extracted from the Sargassum fusiforme induces cell cycle arrest and apoptosis of B16F10 melanoma cells through the PI3K/AKT pathway.

SARGASSUM FUSIFORME: (S. fusiforme) is a brown alga that has been utilized as a medicine for a long time. Polysaccharides extracted from S. fusiforme demonstrate antitumor activities. The impact of S. fusiforme polysaccharides (SFPS 191,212) on the proliferation, apoptosis, and cell cycle kinetics of B16F10 murine melanoma cells were thoroughly investigated in this work. The anticancer activities of the SFPS 191,212 compounds were assayed in the B16F10 cells at both transcriptional and translational levels. The compound exhibited concentration-dependent effects. Moreover, SPFS 191,212 increased the numbers of apoptotic cells and arrested the cell cycle in the S phase of the quantitative real-time PCR. From western blotting, it was verified that the SFPS 191,212 treatment improved the expression of Bax, Caspase-9, and Caspase-3 genes and proteins, while it reduced phosphatidylinositol 3 kinase and Bcl-2 genes and proteins, suggesting the involvement of mitochondria. Overall, SFPS 191,212 can be further explored as a potential functional food or adjuvant agent for the prevention or treatment of melanoma.