Bioactive Compounds from Brown Algae Alleviate Nonalcoholic Fatty Liver Disease: An Extensive Review

Integrating untargeted metabolomics and computational docking for biomarker evaluation: A case study on marine algae-derived ligands

In the post-genomic era, liquid chromatography-mass spectrometry (LC-MS) has emerged as a powerful tool for profiling metabolic profiles in marine macroalgae, which are known for their chemical diversity and pharmacological potential. This study integrates untargeted metabolomics and computational chemistry to accelerate the discovery of therapeutic agents from two red algae (Jania rubens and Scinaia fascicularis) and two brown algae (Hydroclathrus clathratus and Sargassum cinereum). LC-MS-based analysis revealed genotypic variations influencing compound structures, functional groups, and physicochemical properties, which correlated with biological activity scores. Ligand-based virtual screening identified lead compounds with high therapeutic potential, while structure-based virtual screening highlighted stigmasta-5,24(28)-dien-3-ol (3α,24Z) (SM) as the top-ranked ligand, exhibiting a binding affinity of -11.40 kcal/mol. Docking optimization at exhaustiveness levels of 8, 16, and 32 demonstrated that level 8 achieved the best balance of accuracy and computational efficiency, completing in 49.74 s. Post-docking evaluation, including statistical analysis, validated the results, with ubiquinol-cytochrome-c reductase protein showing moderate-to-high activity scores for the selected compounds. These findings underscore the potential of marine algae-derived compounds as therapeutic agents, though further in vitro and in vivo studies are needed to confirm their bioactivity. This work highlights the importance of precise extraction and identification of bioactive compounds for advancing marine natural product research.

Fucoxanthin Targets β1 Integrin to Disrupt Adhesion and Migration in Human Glioma Cells

Glioblastoma, the most aggressive type of primary brain tumor, is marked by high invasiveness and metastasis, posing significant challenges in treatment. Fucoxanthin, a carotenoid derived from brown macroalgae, has demonstrated therapeutic potential in cancer therapy; however, its precise mechanisms of action remain unclear. In this study, we explored the inhibitory effects of fucoxanthin on integrin-mediated adhesion and migration in human glioma U-87 MG cells, shedding light on its potential antimetastatic properties. Our data indicated that fucoxanthin at 1 μM did not affect cell viability but inhibited integrin-mediated adhesion of human glioma U-87 MG cells to fibronectin, a key extracellular matrix (ECM) ligand for integrins, without affecting adhesion to poly-l-lysine, a nonintegrin ligand, indicating its selective impact on integrin-mediated adhesion. Fucoxanthin treatment significantly reduced the size and number of focal adhesions (FA), which play a central role in cell adhesion and migration. In addition, fucoxanthin significantly impaired U-87 MG cell migratory capacity, including a reduced accumulated migration distance and velocity, determined by time-lapse videomicroscopy. Further, fucoxanthin remarkably inhibited integrin engagement-mediated actin polymerization, Vav3 phosphorylation, and the downstream activation of Rac1, FAK, and paxillin, further supporting its role in disrupting integrin signaling and cytoskeletal remodeling. Additionally, complementary experiments utilizing protein binding assays, competitive ELISA, CETSA, DARTS, and MST collectively confirmed the direct interaction between fucoxanthin and β1 integrin as well as reduced ligand affinity of β1 integrin for fibronectin. The theoretical model of molecular docking and the dynamics simulation align with our experimental findings, providing a plausible mechanism by which fucoxanthin competitively inhibits the binding of β1 integrin to fibronectin. In summary, our study highlights fucoxanthin as a promising therapeutic agent that impairs integrin-mediated adhesion and migration in glioblastoma cells by directly targeting β1 integrin and disrupting integrin signaling pathways. These findings offer valuable insights into the potential of fucoxanthin as an antimetastatic agent in glioblastoma treatment.

Protective effects of Trifuhalol A, a Phlorotannin derived from edible Brown seaweed Agarum cribrosum, on dexamethasone-induced muscle atrophy in muscle cells and zebrafish models

Muscle atrophy, characterized by declines in muscle mass and functionality, currently lacks effective therapeutic options, highlighting an urgent need for further research. This research aimed to elucidate the protective effects of Trifuhalol A (TFA), a phlorotannin derived from Agarum cribrosum, against dexamethasone (Dexa)-induced muscle atrophy in zebrafish and C2C12 cells. TFA enhanced differentiation of myoblasts and myotube formation by upregulating MyHC, myogenin, MyoD, p-Akt, and p-mTOR, as well as activation of key downstream effectors of the mTOR pathway, enhancing protein synthesis. It also inhibited key markers associated with muscle atrophy, such as FoxO3a, MuRF-1, and MAFbx. In vivo, TFA treatment prevented the Dexa-induced reduction in myofiber diameter and cross-sectional area (CSA). Zebrafish exploratory behavior tests revealed that TFA improved swimming patterns and food-tracking velocity, indicating improved swimming performance and responsiveness. In conclusion, TFA mitigates Dexa-triggered muscle atrophy, and these effects are associated with improvements in muscle morphology and swimming performance. While the underlying mechanisms remain to be fully elucidated, the observed effects may involve modulation of the Akt/mTOR/FoxO3a signaling pathway. These findings suggest that TFA holds promise as a potential functional ingredient for supporting muscle health and mitigating muscle atrophy.

Protective effects of Kaempferol on hepatic apoptosis via miR-26a-5p enhancement and regulation of TLR4/NF-κB and PKCδ in a rat model of nonalcoholic fatty liver

This study aimed to evaluate kaempferol's, a dietary flavonoid widely present in plants, potential impact on nonalcoholic fatty liver disease (NAFLD) and its underlying mechanisms. In this study, 60 adult male rats were used and divided into a control group receiving a standard pellet diet, a kaempferol-treated group receiving kaempferol (250 mg/kg), a high-fat diet (HFD) group receiving HFD, and a kaempferol-treated HFD group. At the end of the experiment, the total lipid profile and liver enzymes were assayed in the serum. Additionally, oxidative stress (malondialdehyde and superoxide dismutase), inflammatory (tumor necrosis factor-alpha), apoptotic (caspase 3) markers, and nuclear factor-κB (NF-κB) and Toll-like receptor 4 (TLR4) concentrations were assayed in the liver tissues. Furthermore, miR-26a and PKCδ gene expression and beclin 1 immunohistochemical expression were determined in liver tissues. Our findings revealed that kaempferol significantly protects against the development of NAFLD in rats as well as inflammatory, oxidative, and apoptotic changes in their liver tissues by inhibiting PKCδ and the TLR-4/NF-κB signaling pathway while enhancing autophagy (Beclin 1 expression) via upregulating miR-26a expression. Accordingly, kaempferol holds promise as a complementary medication for the prevention of NAFLD. Nonetheless, more research is needed to fully understand its additional effects on liver tissue and to develop novel medications that activate miR-26a. A link between lipid metabolic abnormalities and miRNAs was demonstrated as upregulating miR-26a-5p by kaempferol mitigates the inflammation, apoptosis, and disrupted autophagy via regulating TLR4/NF-κB pathway and PKC in NAFLD.

Gradient experiment reveals physiological stress from heavy metal zinc on the economically valuable seaweed Sargassum fusiforme

Zn is a common heavy metal pollutant in water bodies and accounts for the largest proportion of heavy metal pollutants in many rivers entering the sea. This study investigated the growth and physiological response characteristics of Sargassum fusiforme under different divalent Zn ion concentration gradients. We observed that low concentration Zn2+ treatment (<2 mg L-1) exerted no significant effect on the growth rate, photosynthesis, and nitrogen metabolism-related indicators of S. fusiforme. Treatment with medium to high Zn2+ concentrations (2-25 mg L-1) significantly affected the growth rate, photosynthetic activity, nitrogen absorption rate, antioxidant enzyme activity, membrane lipids, and DNA peroxidation damage-related indicators of S. fusiforme. Under medium-to-high concentration treatments, the SOD activity of S. fusiforme decreased with increasing concentration, and the CAT activity increased with increasing treatment concentration. The MDA and H2O2 contents increased with increasing Zn2+ concentrations. At a Zn2+ concentration of 5 mg L-1, the relative conductivity of S. fusiforme significantly increased. Treatment with higher Zn2+ concentrations significantly increased the 8-hydroxydeoxyguanosine (8-OHdG) content, poly ADP-ribose polymerase (PARP) activity, and Histone H2AX content of S. fusiforme, thus indicating that Zn2+ stress causes DNA damage. All Zn2+ concentrations induced mannitol accumulation, and soluble protein content decreased with increasing Zn2+ concentration. In summary, we observed that a Zn2+ concentration of 2-5 mg L-1 may be the critical value for the response of S. fusiforme to Zn2+ stress. Higher concentrations of Zn in the environment can exert toxic effects on the growth, development, and biomass accumulation of S. fusiforme. This study provides a reference for the risk assessment and aquaculture management of seaweeds.

Multiple health outcomes associated with algae and its extracts supplementation: An umbrella review of systematic reviews and meta-analyses

Algae and its extracts, widely consumed as functional foods, offer numerous health benefits; however, a comprehensive systematic summary of clinical evidence is currently lacking. The study was to assess the available evidence and provide an accurate estimate of the overall effects of algae and its extracts supplementation on various health outcomes. The comprehensive searches in PubMed, Scopus, Embase, Web of Science, and the Cochrane Library until December 22, 2023 were implemented. The random-effects model was employed to pool the overall effect sizes (ESs) and the corresponding 95% confidence intervals (CIs) using Stata software. Moreover, detecting the methodological quality and evidence level of the eligible studies were employed by A Measurement Tool to Assess Systematic Review 2 (AMSTAR2) and the Grading of Recommendations Assessment Development and Evaluation. Ultimately, 25 articles covering 133 health outcomes were included in this umbrella review. The pooled results demonstrated that the algae and its extracts could significantly decrease body weight (ES = -1.65; 95% CI: -1.97, -1.34; p < 0.001), body mass index (BMI) (ES = -0.42; 95% CI: -0.78, -0.07; p = 0.020), waist circumference (WC) (ES = -1.40; 95% CI: -1.40, -1.39; p < 0.001), triglyceride (TG) (ES = -1.38; 95% CI: -2.15, -0.62; p < 0.001), total cholesterol (TC) (ES: -1.40; 95% CI: -2.09, -0.72; p < 0.001), very low-density lipoprotein cholesterol (VLDL-C) (ES = -7.85; 95% CI: -8.55, -7.15; p < 0.001), fasting blood glucose (ES = -2.68; 95% CI: -4.57, -0.79; p = 0.005), glycated hemoglobin (HbA1c) (ES = -0.15; 95% CI: -0.24, -0.07; p < 0.001), systolic blood pressure (ES = -3.21; 95% CI: -5.25, -1.17; p = 0.002), diastolic blood pressure (ES = -3.84; 95% CI: -7.02, -0.65; p = 0.018), alanine transaminase (ES = -0.42; 95% CI: -0.70, -0.14; p = 0.003), and alkaline phosphatase (ES = -0.54; 95% CI: -0.99, -0.10; p = 0.017). Due to the limited number of studies, no benefit was displayed on markers of inflammation and oxidative stress. Considering the suboptimal quality of studies and the insufficient articles pertaining to certain outcomes, further well-designed research is imperative to substantiate the observed findings.

Feed supplementation with the seaweed (Ascophllum Nodosum) extract reduces fat deposition in broiler chickens

In poultry industry, the strategies for elevating of protein accretion with minimizing fat deposition have been applied, and seaweed algae has been focused one of the potential candidates. Accordingly, the purpose of this study was to investigate the effects of algae (Ascophllum Nodosum) extract (AE) on the growth performance and body composition of broiler chickens. A total of 240 one-day-old Ross 308 broiler chickens were allotted to 4 dietary treatment groups and fed experimental diets containing different concentrations of AE for 35 d as follows: 0 mg/kg (control, CON), 1,250 mg/kg (LAE), 2,500 mg/kg (MAE), or 5,000 mg/kg (HAE). At the end of the experiment, 40 chickens were sacrificed and samples of their blood, breast muscle, liver, and abdominal fat were collected and analyzed. Growth performance was improved in the LAE group compared to that in the CON (P < 0.05). The weight of abdominal fat was lower in the HAE group than in the CON group (P < 0.05). Serum triglyceride levels were also decreased in the HAE group compared to those in the CON and LAE groups (P < 0.05). Adipocytes were smaller in the HAE group than in all other treatments, and their size distribution was shifted more towards smaller adipocytes compared to those in the LAE group (P < 0.05). Relative mRNA levels in abdominal adipose tissue of fatty acid synthase and stearyl-CoA desaturase, which are involved in fatty acid synthesis, were all downregulated by supplementation with AE (P < 0.05). In addition, the protein levels of peroxisome proliferator-activated receptor gamma were decreased and the ratio of phosphorylated acetyl-CoA carboxylase to total ACC was increased, both of which indicate that lipogenesis was suppressed (P < 0.05). Hepatic transcript levels of sterol regulatory element-binding protein and its downstream enzymes fatty acid synthase and sterol-CoA desaturase were also lower in all AE treatments compared to those in the CON group (P < 0.05). These results indicate that the seaweed algae (Ascophllum Nodosum) extract reduces fat accumulation in both adipose tissue and the liver by modulating lipogenesis.

Fucoxanthin Mitigates High-Fat-Induced Lipid Deposition and Insulin Resistance in Skeletal Muscle through Inhibiting PKM1 Activity

Glucose and lipid metabolism dysregulation in skeletal muscle contributes to the development of metabolic disorders. The efficacy of fucoxanthin in alleviating lipid metabolic disorders in skeletal muscle remains poorly understood. In this study, we systematically investigated the impact of fucoxanthin on mitigating lipid deposition and insulin resistance in skeletal muscle employing palmitic acid-induced lipid deposition in C2C12 cells and ob/ob mice. Fucoxanthin significantly alleviated PA-induced skeletal muscle lipid deposition and insulin resistance. In addition, fucoxanthin prominently upregulated the expression of lipid metabolism-related genes (Pparα and Cpt-1), promoting fatty acid β-oxidation metabolism. Additionally, fucoxanthin significantly increased the expression of Pgc-1α and Tfam, elevated the mtDNA/nDNA ratio, and reduced ROS levels. Further, we identified pyruvate kinase muscle isozyme 1 (PKM1) as a high-affinity protein for fucoxanthin by drug affinity-responsive target stability and LC-MS and confirmed their robust interaction by CETSA, microscale thermophoresis, and circular dichroism. Supplementation with pyruvate, the product of PKM1, significantly attenuated the beneficial effects of fucoxanthin on lipid deposition and insulin resistance. Mechanistically, fucoxanthin reduced glucose glycolysis rate and enhanced mitochondrial biosynthesis and fatty acid β-oxidation through inhibiting PKM1 activity, thereby alleviating lipid metabolic stress. These findings present a novel clinical strategy for treating metabolic diseases using fucoxanthin.

Expression and Characterization of an Efficient Alginate Lyase from Psychromonas sp. SP041 through Metagenomics Analysis of Rotten Kelp

Alginate is derived from brown algae, which can be cultivated in large quantities. It can be broken down by alginate lyase into alginate oligosaccharides (AOSs), which exhibit a higher added value and better bioactivity than alginate. In this study, metagenomic technology was used to screen for genes that code for high-efficiency alginate lyases. The candidate alginate lyase gene alg169 was detected from Psychromonas sp. SP041, the most abundant species among alginate lyase bacteria on selected rotten kelps. The alginate lyase Alg169 was heterologously expressed in Escherichia coli BL21 (DE3), Ni-IDA-purified, and characterized. The optimum temperature and pH of Alg169 were 25 °C and 7.0, respectively. Metal ions including Mn2+, Co2+, Ca2+, Mg2+, Ni2+, and Ba2+ led to significantly increased enzyme activity. Alg169 exhibited a pronounced dependence on Na+, and upon treatment with Mn2+, its activity surged by 687.57%, resulting in the highest observed enzyme activity of 117,081 U/mg. Bioinformatic analysis predicted that Alg169 would be a double-domain lyase with a molecular weight of 65.58 kDa. It is a bifunctional enzyme with substrate specificity to polyguluronic acid (polyG) and polymannuronic acid (polyM). These results suggest that Alg169 is a promising candidate for the efficient manufacturing of AOSs from brown seaweed.

Very low-carbohydrate diet with higher protein ratio improves lipid metabolism and inflammation in rats with diet-induced nonalcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is commonly associated with obesity, and it is mainly treated through lifestyle modifications. The very low-carbohydrate diet (VLCD) can help lose weight rapidly but the possible effects of extreme dietary patterns on lipid metabolism and inflammatory responses in individuals with NAFLD remain debatable. Moreover, VLCD protein content may affect its effectiveness in weight loss, steatosis, and inflammatory responses. Therefore, we investigated the effects of VLCDs with different protein contents in NAFLD rats and the mechanisms underlying these effects. After a 16-week inducing period, the rats received an isocaloric normal diet (NC group) or a VLCD with high or low protein content (NVLH vs. NVLL group, energy ratio:protein/carbohydrate/lipid=20/1/79 vs. 6/1/93) for the next 8 weeks experimental period. We noted that the body weight decreased in both the NVLH and NVLL groups; nevertheless, the NVLH group demonstrated improvements in ketosis. The NVLL group led to hepatic lipid accumulation, possibly by increasing very-low-density lipoprotein receptor (VLDLR) expression and elevating liver oxidative stress, subsequently activating the expression of Nrf2, and inflammation through the TLR4/TRIF/NLRP3 and TLR4/MyD88/NF-κB pathway. The NVLH was noted to prevent the changes in VLDLR and the TLR4-inflammasome pathway partially. The VLCD also reduced the diversity of gut microbiota and changed their composition. In conclusion, although low-protein VLCD consumption reduces BW, it may also lead to metabolic disorders and changes in microbiota composition; nevertheless, a VLCD with high protein content may partially alleviate these limitations.

Integrative proteomics and metabolomics explore the effect and mechanism of Qiyin granules on improving nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) has emerged as a prominent global health concern, representing a substantial burden within the spectrum of chronic liver diseases. Despite its escalating prevalence, a definitive therapeutic strategy or efficacious pharmacological intervention for NAFLD has yet to receive official approval to date. While Fu Fang Qiyin granules have exhibited efficacy in addressing NAFLD, the intricacies of their underlying mechanism of action remain inadequately elucidated. In this study, we substantiated the ameliorative impact of Qiyin on highfat diet (HFD)induced NAFLD in rat models. The results of metabonomics showed that 108 potential biomarkers in serum and urine related to amino acid metabolism, energy metabolism, and pyrimidine metabolism, have returned to normal levels compared to the model group. Hepatic transcriptomics further indicated that Qiyin potentially confers protective effects against NAFLD by mediating liver inflammation and fibrosis through lumican (LUM) and decorin (DCN). In summation, our investigation provides compelling evidence affirming the therapeutic promise of Qiyin for NAFLD. It elucidates the underlying mechanistic pathways, furnishing a compelling rationale for its prospective clinical application.

Laminaria japonica Aresch-Derived Fucoidan Ameliorates Hyperlipidemia by Upregulating LXRs and Suppressing SREBPs

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality worldwide, and hyperlipidemia is one major inducing factor of CVD. It is worthy to note that fucoidans are reported to have hypolipidemic activity with species specificity; however, the underlying mechanisms of action are far from clarification. This study is aimed at investigating the plasma lipid-lowering mechanisms of the fucoidan from L. japonica Aresch by detecting the levels of hepatic genes that are involved in lipid metabolism. Our results demonstrated that the fucoidan F3 significantly lowered total cholesterol and triglyceride in C57BL/6J mice fed a high-fat diet. In the mouse liver, fucoidan F3 intervention significantly increased the gene expression of peroxisome proliferator-activated receptor (PPAR) α, liver X receptor (LXR) α and β, and ATP-binding cassette transporter (ABC) G1 and G8 and decreased the expression of proprotein convertase subtilisin/kexin type 9 (PCSK9), low-density lipoprotein receptor, cholesterol 7 alpha-hydroxylase A1, and sterol regulatory element-binding protein (SREBP) 1c and SREBP-2. These results demonstrated that the antihyperlipidemic effects of fucoidan F3 are related to its activation of PPARα and LXR/ABC signaling pathways and inactivation of SREBPs. In conclusion, fucoidan F3 may be explored as a potential compound for prevention or treatment of lipid disorders.