Fucoidan from Ecklonia maxima is a powerful inhibitor of the diabetes-related enzyme, α-glucosidase

A review of healthy role of dietary fiber in modulating chronic diseases

Dietary fiber (DF) is considered an interventional diet beneficial for human health. High DF intake effectively reduces the incidence of three major chronic diseases, type 2 diabetes (T2DM), cardiovascular disease (CVD), and colorectal cancer (CRC). The health benefits of DF are closely related to their physicochemical properties with major positive roles in human digestion and intestinal health. However, mechanisms linking DF with diseases remain unclear. The development of genomics, metabolomics, and immunology, and the powerful combination of animal models and clinical trials, have facilitated a better understanding of the relationships between DF and diseases. Accumulating evidence suggests that the physical existence of DF and DF-microbiota interaction are the key parameters controlling the action mechanisms of DF in chronic diseases. Therefore, this review discusses the potential mechanism of DF modulating T2DM, CVD, and CRC, therefore providing a theoretical basis for more effective use of DF to intervene in chronic diseases.

Physiochemical changes, metabolite discrepancies of brown seaweed-derived sulphated polysaccharides in the upper gastrointestinal tract and their effects on bioactive expression

Brown seaweed-derived polysaccharides, notably fucoidan and laminarin, are known for their extensive array of bioactivities and physicochemical properties. However, the effects of upper digestive tract modification on the bioactive performance of fucoidan and laminarin fractions (FLFs) sourced from Australian native species are largely unknown. Here, the digestibility and bioaccessibility of FLFs were evaluated by tracking the dynamic changes in reducing sugar content (CR), profiling the free monosaccharide composition using LC-MS, and comparing high-performance gel permeation chromatography profile variation via LC-SEC-RI. The effects of digestive progression on bioactive performance were assessed by comparing the antioxidant and antidiabetic potential of FLFs and FLF digesta. We observed that molecular weight (Mw) decreased during gastric digestion indicating that FLF aggregates were disrupted in the stomach. During intestinal digestion, Mw gradually decreased and CR increased indicating cleavage of glycosidic bonds releasing free sugars. Although the antioxidant and antidiabetic capacities were not eliminated by the digestion progression, the bioactive performance of FLFs under a digestive environment was reduced contrasting with the same concentration level of the undigested FLFs. These data provide comprehensive information on the digestibility and bioaccessibility of FLFs, and shed light on the effects of digestive progression on bioactive expression.

Effect of in vitro simulated digestion on the physicochemical properties and pancreatic lipase inhibitory activity of fucoidan

BACKGROUND

Fucoidan has an anti-obesity effect. However, there are few studies on its mechanism. In this study, we investigated the in vitro and in silico inhibitory properties of fucoidan against pancreatic lipase for the first time. We examined the changes in composition, structure, and pancreatic lipase inhibition of fucoidan during in vitro digestion.

RESULTS

Simulated saliva-gastrointestinal digestion resulted in a slight decrease in the molecular weight of fucoidan but no significant changes in the monosaccharide composition, sulfate content, and functional groups. Moreover, the digestion process significantly increased the inhibition of pancreatic lipase by fucoidan. The study on the type of inhibition showed that the inhibition of pancreatic lipase by fucoidan belonged to mixed inhibition with competitive inhibition. Molecular docking analysis showed that fucoidan could bind to the active site of pancreatic lipase.

CONCLUSION

This study indicates that fucoidan can be a potential functional food for anti-obesity. © 2024 Society of Chemical Industry.

Biomedical potency and mechanisms of marine polysaccharides and oligosaccharides: A review

Derived from bountiful marine organisms (predominantly algae, fauna, and microorganisms), marine polysaccharides and marine oligosaccharides are intricate macromolecules that play a significant role in the growth and development of marine life. Recently, considerable attention has been paid to marine polysaccharides and marine oligosaccharides as auspicious natural products due to their promising biological attributes. Herein, we provide an overview of recent advances in the miscellaneous biological activities of marine polysaccharides and marine oligosaccharides that encompasses their anti-cancer, anti-inflammatory, antibacterial, antiviral, antioxidant, anti-diabetes mellitus, and anticoagulant properties. Furthermore, we furnish a concise summary of the underlying mechanisms governing the behavior of these biological macromolecules. We hope that this review inspires research on marine polysaccharides and marine oligosaccharides in medicinal applications while offering fresh perspectives on their broader facets.

MiR-146b-5p enriched bioinspired exosomes derived from fucoidan-directed induction mesenchymal stem cells protect chondrocytes in osteoarthritis by targeting TRAF6

Osteoarthritis (OA) is a common degenerative joint disease characterized by progressive cartilage degradation and inflammation. In recent years, mesenchymal stem cells (MSCs) derived exosomes (MSCs-Exo) have attracted widespread attention for their potential role in modulating OA pathology. However, the unpredictable therapeutic effects of exosomes have been a significant barrier to their extensive clinical application. In this study, we investigated whether fucoidan-pretreated MSC-derived exosomes (F-MSCs-Exo) could better protect chondrocytes in osteoarthritic joints and elucidate its underlying mechanisms. In order to evaluate the role of F-MSCs-Exo in osteoarthritis, both in vitro and in vivo studies were conducted. MiRNA sequencing was employed to analyze MSCs-Exo and F-MSCs-Exo, enabling the identification of differentially expressed genes and the exploration of the underlying mechanisms behind the protective effects of F-MSCs-Exo in osteoarthritis. Compared to MSCs-Exo, F-MSCs-Exo demonstrated superior effectiveness in inhibiting inflammatory responses and extracellular matrix degradation in rat chondrocytes. Moreover, F-MSCs-Exo exhibited enhanced activation of autophagy in chondrocytes. MiRNA sequencing of both MSCs-Exo and F-MSCs-Exo revealed that miR-146b-5p emerged as a promising candidate mediator for the chondroprotective function of F-MSCs-Exo, with TRAF6 identified as its downstream target. In conclusion, our research results demonstrate that miR-146b-5p encapsulated in F-MSCs-Exo effectively inhibits TRAF6 activation, thereby suppressing inflammatory responses and extracellular matrix degradation, while promoting chondrocyte autophagy for the protection of osteoarthritic cartilage cells. Consequently, the development of a therapeutic approach combining fucoidan with MSC-derived exosomes provides a promising strategy for the clinical treatment of osteoarthritis.

Optimization of fucoidan recovery by ultrasound-assisted enzymatic extraction from South African kelp, Ecklonia maxima

Fucoidan, a sulphated polysaccharide, is found exclusively in brown seaweeds and has been reported to possess a wide range of biological functionalities. Fucoidans are found within the cell wall of brown seaweeds, which is composed of recalcitrant cellulose and hemicellulose. This hampers the recovery of fucoidans. In addition, fucoidans are found within a network of viscous hydrocolloids, alginates, further complicating their recovery. Traditionally, the hot water extraction method is used to recover fucoidans from brown seaweed, however, this is characterized by low yields and long extraction time. To combat these issues, several novel extraction technologies have been introduced, these include ultrasound-assisted extraction and enzyme-assisted extraction. Thus, the main aim of this study was to investigate and optimize fucoidan recovery from Ecklonia maxima based on ultrasound-assisted enzymatic extraction. The impact of temperature (40-65 °C), ultrasound intensity (0-118 W·cm-2), enzyme dosage (0-0.05 ml·g-1) and pH (4.5-6) on total dissolved, total carbohydrates and inorganic sulphates yields was studied. The application of ultrasound-assisted enzymatic extraction mainly improved the extraction of total carbohydrates. Ultrasound significantly improves the kinetics and extraction of fucoidan, but there was no merit when it was applied with enzymes. Results reveal that at optimized conditions, the fucoidan extracted 79.13 mg⋅g-1 (7.9 % w/w) of algal dry weight. The present study provides insight into the extraction potentials of enzyme-assisted extraction, ultrasound-assisted extraction, and ultrasound-assisted enzymatic extraction.

Research progress on the hypoglycemic activity and mechanisms of natural polysaccharides

The incidence of diabetes, as a metabolic disease characterized by high blood sugar levels, is increasing every year. The predominantly western medicine treatment is associated with certain side effects, which has prompted people to turn their attention to natural active substances. Natural polysaccharide is a safe and low-toxic natural substance with various biological activities. Hypoglycemic activity is one of the important biological activities of natural polysaccharides, which has great potential for development. A systematic review of the latest research progress and possible molecular mechanisms of hypoglycemic activity of natural polysaccharides is of great significance for better understanding them. In this review, we systematically reviewed the relationship between the hypoglycemic activity of polysaccharides and their structure in terms of molecular weight, monosaccharide composition, and glycosidic bonds, and summarized underlying molecular mechanisms the hypoglycemic activity of natural polysaccharides. In addition, the potential mechanisms of natural polysaccharides improving the complications of diabetes were analyzed and discussed. This paper provides some valuable insights and important guidance for further research on the hypoglycemic mechanisms of natural polysaccharides.

A review on anti-nutritional factors: unraveling the natural gateways to human health

Humans are constantly facing multiple health challenges from both communicable and non-communicable diseases that significantly affect their health. Additionally, drug resistance or failure has made the situation even worse and poses serious challenges for researchers to develop new drugs. Hence, to address these problems, there is an urgent need to discover and develop timely and long-term-based therapeutic treatments from different sources. One such approach is harnessing the potential of plant secondary metabolites. Plants have been utilized for therapeutic purposes in addition to being used for nutritional benefits. In the last two decades, plant-based drug developments have been one of the effective means of treating human diseases owing to their multiple functions. More recently, anti-nutritional factors (ANFs) have emerged as one of the important targets for novel plant-based drug development due to their multifaceted and potential pharmacological properties. However, their anti-nutritional properties have been the major setback for their limited success in the pharmacological sector. In this review, we provide an overview of ANFs and their beneficial roles in preventing human diseases with multiple case studies. We also highlight the recent developments and applications of ANFs in the food industry, agriculture, and pharmaceutics with future perspectives. Furthermore, we evaluate meta-analyses on ANFs from the last 30 years in relation to their function in human health benefits. This review is an endeavor to reevaluate the merit of these natural compounds and explore their potential for both human and animal health.

Potential Application of Marine Fucosyl-Polysaccharides in Regulating Blood Glucose and Hyperglycemic Complications

Diabetes mellitus (DM) has become the world's third major disease after tumors and cardiovascular disease. With the exploitation of marine biological resources, the efficacy of using polysaccharides isolated from marine organisms in blood glucose regulation has received widespread attention. Some marine polysaccharides can reduce blood glucose by inhibiting digestive enzyme activity, eliminating insulin resistance, and regulating gut microbiota. These polysaccharides are mainly fucose-containing sulphated polysaccharides from algae and sea cucumbers. It follows that the hypoglycemic activity of marine fucosyl-polysaccharides is closely related to their structure, such as their sulfate group, monosaccharide composition, molecular weight and glycosidic bond type. However, the structure of marine fucosyl-polysaccharides and the mechanism of their hypoglycemic activity are not yet clear. Therefore, this review comprehensively covers the effects of marine fucosyl-polysaccharides sources, mechanisms and the structure-activity relationship on hypoglycemic activity. Moreover, the potential regulatory effects of fucosyl-polysaccharides on vascular complications caused by hyperglycemia are also summarized in this review. This review provides rationales for the activity study of marine fucosyl-polysaccharides and new insights into the high-value utilization of marine biological resources.

Sulfated Polysaccharides from Macroalgae-A Simple Roadmap for Chemical Characterization

The marine environment presents itself as a treasure chest, full of a vast diversity of organisms yet to be explored. Among these organisms, macroalgae stand out as a major source of natural products due to their nature as primary producers and relevance in the sustainability of marine ecosystems. Sulfated polysaccharides (SPs) are a group of polymers biosynthesized by macroalgae, making up part of their cell wall composition. Such compounds are characterized by the presence of sulfate groups and a great structural diversity among the different classes of macroalgae, providing interesting biotechnological and therapeutical applications. However, due to the high complexity of these macromolecules, their chemical characterization is a huge challenge, driving the use of complementary physicochemical techniques to achieve an accurate structural elucidation. This review compiles the reports (2016-2021) of state-of-the-art methodologies used in the chemical characterization of macroalgae SPs aiming to provide, in a simple way, a key tool for researchers focused on the structural elucidation of these important marine macromolecules.

Eckmaxol Isolated from Ecklonia maxima Attenuates Particulate-Matter-Induced Inflammation in MH-S Lung Macrophage

Airborne particulate matter (PM) originating from industrial processes is a major threat to the environment and health in East Asia. PM can cause asthma, collateral lung tissue damage, oxidative stress, allergic reactions, and inflammation. The present study was conducted to evaluate the protective effect of eckmaxol, a phlorotannin isolated from Ecklonia maxima, against PM-induced inflammation in MH-S macrophage cells. It was found that PM induced inflammation in MH-S lung macrophages, which was inhibited by eckmaxol treatment in a dose-dependent manner (21.0−84.12 µM). Eckmaxol attenuated the expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) in PM-induced lung macrophages. Subsequently, nitric oxide (NO), prostaglandin E-2 (PGE-2), and pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α) were downregulated. PM stimulated inflammation in MH-S lung macrophages by activating Toll-like receptors (TLRs), nuclear factor-kappa B (NF-κB), and mitogen-activated protein kinase (MAPK) pathways. Eckmaxol exhibited anti-inflammatory properties by suppressing the activation of TLRs, downstream signaling of NF-κB (p50 and p65), and MAPK pathways, including c-Jun N-terminal kinase (JNK) and p38. These findings suggest that eckmaxol may offer substantial therapeutic potential in the treatment of inflammatory diseases.

Isolation and characterization of fucoidan from four brown algae and study of the cardioprotective effect of fucoidan from Sargassum wightii against high glucose-induced oxidative stress in H9c2 cardiomyoblast cells

Oxidative stress plays a vital role in the initiation and progression of diabetic cardiomyopathy (DCM). Increased cardiac dysfunction and apoptosis in DCM are independent factors associated with hypertension or coronary artery disease. Fucoidan, a class of sulfated polysaccharides, is widely used as food supplements and reported to have various pharmacological properties. However, the pharmacological property of Indian seaweeds remains unexplored. The present study is focused on isolating and characterizing the fucoidan from four brown seaweeds such as Sargassum wightii (SwF), Sargassum swartzii (SsF), Sargassum polycystum (SpF), Turbinaria ornata (ToF), and aimed to investigate cardioprotective effect of fucoidan against High Glucose (HG) induced oxidative stress in H9c2 cells. The mild acid hydrolysis method was used to isolate crude fucoidan from four brown seaweeds purified by the FPLC system. The biochemical composition analysis showed that SwF had a high content of fucoidan and sulfate, followed by SsF, SpF, and ToF. Further, FTIR, XRD, NMR, and SEM analysis confirmed the isolated fucoidan structures. SwF showed higher DPPH activity compared to another isolated fucoidan. In vitro studies with SwF revealed significantly decreased cytotoxicity, prevented the loss of MMP, reduced lipid peroxidation, and increased cellular enzymatic and non-enzymatic activity. qRT-PCR results showed SwF significantly upregulated the Nrf2, HO-1, NQO1, and Bcl2 and down-regulated the Bax and Caspase-3 mRNA expression compared to HG-treated cells. In conclusion, SwF could be used to develop functional foods for diabetic-mediated CVD complications compared to another isolated fucoidan. PRACTICAL APPLICATIONS: Bioactive carbohydrates have gained significant interest among researchers to improve human health. The biomedical field showed great interest in seaweed research in managing various diseases. In particular, seaweeds contain many bioactive compounds because of their chemical and biological diversity. Despite the various beneficial effects of fucoidan in CVD, the therapeutic potential of Indian seaweeds remains largely unexplored. Hence, this study isolated fucoidan from four brown seaweeds and studied their bioactive properties. Results revealed that SwF showed higher free radical scavenging activity compared to another isolated fucoidan. Therefore, SwF was selected for the in vitro study. SwF increased the cytoprotection through increasing antioxidant levels against oxidative stress in H9c2 cells. Staining analysis showed SwF increased cellular protection via inhibiting ROS protection and increasing MMP. Overall, fucoidan from SwF could be developed as a functional food for CVD.

Design, Synthesis and Pharmacological Evaluation of 2-(3-BenzoyI-4-Hydroxy-1,1-Dioxido-2H-Benzo[e][1,2]thiazin-2-yI)-N-(2-Bromophenyl) Acetamide as Antidiabetic Agent

PURPOSE

The present study is based on screening new and potent synthetic heterocyclic compounds as anti-diabetic drugs using various computational tools, lab experiments, and animal models.

METHODS

A potent synthetic compound 2-(3-benzoyl-4-hydroxy-1,1-dioxido-2H-benzo[e][1,2]thiazin-2-yl)-1-(2-bromophenyl) acetamide (FA2) was checked against diabetes and screened via enzyme inhibition assays, enzyme kinetics against alpha-glucosidase and alpha-amylase. Protein-ligand interaction was analyzed via molecular docking and toxicological analysis via ADMET. Experimental animals were used to examine the compound FA2 safety, delivery, and check various biochemical tests related to diabetes like fasting glucose sugar, cholesterol, triglyceride, HbAc1, creatinine, and insulin level. Histography of liver, kidney, and pancreas was also performed.

RESULTS

Results showed that FA2 had binding energy of -7.02 Kcal/mol and -6.6 kcal/mol against α-glucosidase (PDB ID: 2ZE0) and α-amylase (PDB ID: 1B2Y), respectively. Moreover, in vitro enzyme inhibition assays and enzyme kinetics against α-glucosidase and α-amylase were performed, and FA2 showed IC50 at 5.17 ± 0.28 µM and 18.82 ± 0.89 µM concentrations against α-glucosidase and α-amylase, respectively. Kinetics studies showed that the FA2 compound impeded α-glucosidase and α-amylase as a non-competitive mode of inhibition with Ki' values -0.320 ± 0.001 and 0.141 ± 0.01, respectively. FA2 was further analyzed on alloxan-induced mice for 21 days. Biochemical tests (fasting glucose sugar, cholesterol, triglyceride, HbAc1, creatinine, and insulin levels) and histological examination of liver and kidney showed that the FA2 compound showed better results than acarbose. Histology of pancreas found to show the maintenance of normal pancreatic acini and Langerhans islets in FA2 treated mice compared to acarbose and nontreated diabetic controls.

CONCLUSION

Investigating anti-diabetic potential of FA2 compound showed that the selected benzothiazine derivative has tremendous importance in reducing dose concentration and side effects.

Occurrence of different fucoidanase genes in Flavobacterium sp. SW and enzyme characterization

Fucoidans are hetero-sulfated polysaccharides that are widely distributed in brown algae and have been extensively studied for their various biological activities. The structure-function relationship of fucoidans remains unclear but can be studied using fucoidan-degrading enzymes (fucoidanases). Here, we isolated and identified Flavobacterium sp. SW as a microbial strain that can grow on fucoidan from Cladosiphon okamuranus as the sole carbon source. Genomic analysis of this strain revealed the presence of two genes, swfct and swfcn2, that are homologous to fct114 from Luteolibacter algae H18 and fcnA from Psychromonas sp. SW5A, respectively. The gene products were produced in Escherichia coli and showed significantly different specificities for fucoidan. Swfct catalyzed the degradation of deacetylated fucoidan from C. okamuranus, and Swfcn2 degraded fucoidans from Saccharina sculpera and Macrocystis pyrifera. The general properties of Swfct were examined by measuring the amounts of reducing ends produced by the enzymatic reaction, and the enzyme properties of Swfcn2 were evaluated by carbohydrate-polyacrylamide gel electrophoresis. Our findings indicate that one microbial strain can harbor genes encoding two different types of fucoidanases.

Inhibitory Potential of Six Brown Algae from the Persian Gulf on α-Glucosidase and In Vivo Antidiabetic Effect of Sirophysalis Trinodis

Background

Brown algae have gained worldwide attention due to their significant biological activities, such as antidiabetic properties. In the present study, the antidiabetic properties of six brown algae from the Persian Gulf were investigated.

Methods

An experimental study was conducted from 2017 to 2019 to examine the inhibitory effects of six brown algae against the α-glucosidase activity. Methanol (MeOH) and 80% MeOH extracts of Colpomenia sinuosa, Sargassum acinaciforme, Iyengaria stellata, Sirophysalis trinodis, and two accessions of Polycladia myrica were analyzed. The effect of 80% MeOH extracts of Sirophysalis trinodis on blood glucose levels in streptozotocin-induced diabetic rats was evaluated. Chemical constituents of brown algae were analyzed using thin-layer chromatography and liquid chromatography-mass spectrometry techniques. Data were analyzed using SPSS software, and P<0.05 was considered statistically significant.

Results

The 80% MeOH extracts of Iyengaria stellata (IC50=0.33±0.15 μg/mL) and Colpomenia sinuosa (IC50=3.50±0.75 μg/mL) as well as the MeOH extracts of Colpomenia sinuosa (IC50=3.31±0.44 μg/mL) exhibited stronger inhibitory effect on α-glucosidase than the acarbose (IC50=160.15±27.52 μg/mL, P<0.001). The 80% MeOH extracts of Sirophysalis trinodis reduced postprandial blood glucose levels in diabetic rats compared to the control group (P=0.037). Fucoxanthin was characterized as the major antidiabetic agent in most of the algal extracts.

Conclusion

Sirophysalis trinodis is recommended as a novel source for isolation and identification of potential antidiabetic compounds due to its high in vivo and in vitro antidiabetic effects.

Marine Bioactive Compounds Derived from Macroalgae as New Potential Players in Drug Delivery Systems: A Review

The marine algal ecosystem is characterized by a rich ecological biodiversity and can be considered as an unexploited resource for the discovery and isolation of novel bioactive compounds. In recent years, marine macroalgae have begun to be explored for their valuable composition in bioactive compounds and opportunity to obtain different nutraceuticals. In comparison with their terrestrial counterparts, Black Sea macroalgae are potentially good sources of bioactive compounds with specific and unique biological activities, insufficiently used. Macroalgae present in different marine environments contain several biologically active metabolites, including polysaccharides, oligosaccharides, polyunsaturated fatty acids, sterols, proteins polyphenols, carotenoids, vitamins, and minerals. As a result, they have received huge interest given their promising potentialities in supporting antitumoral, antimicrobial, anti-inflammatory, immunomodulatory, antiangiogenic, antidiabetic, and neuroprotective properties. An additional advantage of ulvans, fucoidans and carrageenans is the biocompatibility and limited or no toxicity. This therapeutic potential is a great natural treasure to be exploited for the development of novel drug delivery systems in both preventive and therapeutic approaches. This overview aims to provide an insight into current knowledge focused on specific bioactive compounds, which represent each class of macroalgae e.g., ulvans, fucoidans and carrageenans, respectively, as valuable potential players in the development of innovative drug delivery systems.

Isolation and Characterization of Efficient Active Compounds Using High-Performance Centrifugal Partition Chromatography (CPC) from Anti-Inflammatory Activity Fraction of Ecklonia maxima in South Africa

Ecklonia maxima is a brown seaweed, which is abundantly distributed in South Africa. This study investigated an efficient approach using high-performance centrifugal partition chromatography (HPCPC), which has been successfully developed for the isolation and purification of phlorotannins, eckmaxol, and dieckol from the ethyl acetate fraction of E. maxima (EEM). We evaluated EEM for its inhibitory effect against lipopolysaccharide (LPS)-induced inflammatory responses in zebrafish embryos. The separation of eckmaxol and dieckol from samples of EEM using HPCPC was found to be of high purity and yield under an optimal solvent system composed of n-hexane:ethyl acetate:methanol:water (2:7:3:7, v/v/v/v). To evaluate the anti-inflammatory efficacy of EEM containing active compounds, zebrafish embryos exposed to LPS were compared with and without EEM treatment for nitric oxide (NO) production, reactive oxygen species (ROS) generation, and cell death two days after fertilization. These evaluations indicate that EEM alleviated inflammation by inhibiting cell death, ROS, and NO generation induced by LPS treatment. According to these results, eckmaxol and dieckol isolated from brown seaweed E. maxima could be considered effective anti-inflammatory agents as pharmaceutical and functional food ingredients.

Low molecular weight fucoidan alleviates cerebrovascular damage by promoting angiogenesis in type 2 diabetes mice

Diabetes leading to brain glucose metabolism disorders and cerebrovascular complications. Fucoidan is a kind of sulfated polysaccharides which found in brown algae, has multiply bioactivities and considered to be a promising therapeutic agent. Despite the increasing amount of evidence suggesting the diabetes protective role of fucoidans, the effect of fucoidan on brain abnormalities in type 2 diabetes mellitus patients remains unclear. In this study a low molecular weight fucoidan (LMWF) was obtained from Saccharina japonica and its effect on the cerebrovascular damage in db/db mice was investigated. Results were shown after LMWF treatment, the degree of cerebrovascular damage, the number of apoptotic neuronal cells and the inflammation were all decreased in db/db mice. Moreover, LMWF could up-regulates CD34 and VEGFA expression in db/db mice brain, and the subintestinal vessel angiogenesis in zebrafish was also promoted by LMWF. Moreover, the lumen formation of HUVEC endothelial cells was rescued by LMWF which was destroyed in high glucose treated endothelial cells. Further study found, LMWF alleviates vascular injury by up-regulating the expression level of phosphorylated PI3K and phosphorylated AKT. Our study indicates that LMWF has the potential to develop a cerebrovascular protection agent for type 2 diabetes patients.

Anti-Fine Dust Effect of Fucoidan Extracted from Ecklonia maxima Laves in Macrophages via Inhibiting Inflammatory Signaling Pathways

Brown seaweeds contain fucoidan, which has numerous biological activities. Here, the anti-fine-dust activity of fucoidan extracted from Ecklonia maxima, an abundant brown seaweed from South Africa, was explored. Fourier transmittance infrared spectroscopy, high-performance anion-exchange chromatography with pulsed amperometric detection analysis of the monosaccharide content, and nuclear magnetic resonance were used for the structural characterization of the polysaccharides. The toll-like receptor (TLR)-mediated nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways were evaluated. The results revealed that E. maxima purified leaf fucoidan fraction 7 (EMLF7), which contained the highest sulfate content, showed the best anti-inflammatory activity by attenuating the TLR-mediated NF-κB/MAPK protein expressions in the particulate matter-stimulated cells. This was solidified by the successful reduction of Prostaglandin E2, NO, and pro-inflammatory cytokines, such as TNF-α, IL-6, and IL-1β. The current findings confirm the anti-inflammatory activity of EMLF7, as well as the potential use of E. maxima as a low-cost fucoidan source due to its abundance. This suggests its further application as a functional ingredient in consumer products.

Structural characterization of a novel polysaccharide from sweet corncob that inhibits glycosylase in STZ-induced diabetic rats : Structural characterization of a novel polysaccharide

In the current study, we extracted a polysaccharide from sweet corncob and evaluated its hypoglycemic function. After collection in water, alcohol precipitation, and purification by DEAE-52 and Sephadex G-100 columns, we obtained a polysaccharide (SCP50) that was composed primarily of mannose and glucose (9.73:190.27), with a molecular weight of 9280.33 Da. We demonstrated that SCP50 exhibited significant inhibition of α-glucosidase activity, with an IC50 of 4.866 mg/mL, K_m of 1.297 × 10^-3, and V_max of 0.076 mol/L·min^-1 in vitro. We also observed that SCP50 markedly attenuated disaccharidase (maltase, sucrase, and lactase) activity in a rat model of T2DM. We conclude that SCP50 exerts a hypoglycemic effect via inhibition of intestinal glycosylase. These results thus provide new insight into the hypoglycemic action underlying sweet corncob polysaccharide's effects.

Beneficial effects of seaweed-derived dietary fiber: Highlights of the sulfated polysaccharides

Seaweeds and their derivatives are important bioresources of natural bioactive compounds. Nutritional studies indicate that dietary fibers derived from seaweeds have great beneficial potentials in human health and can be developed as functional food. Moreover, sulfated polysaccharides are more likely to be the main bioactive components which are widely distributed in various species of seaweeds including Phaeophyceae, Rhodophyceae and Chlorophyceae. The catabolism by gut microbiota of the seaweeds-derived dietary fibers (DFs) may be one of the pivotal pathways of their physiological functions. Therefore, in this review, we summarized the latest results of the physiological characteristics of seaweed-derived dietary fiber and highlighted the roles of sulfated polysaccharides in the potential regulatory mechanisms against disorders. Meanwhile, the effects of different types of seaweed-derived dietary fiber on gut microbiota were discussed. The analysis of the structure-function correlations and gut microbiota related mechanisms and will contribute to further better applications in food and biotherapeutics.

Health benefits and potential applications of fucoidan (FCD) extracted from brown seaweeds in aquaculture: An updated review

Nowadays, the application of immunomodulators in aquaculture has become of an urgent need because of high incidence of fish and shrimp diseases. For a long time, researchers have paid great interest to find suitable, relatively economical, and environmentally safe immunostimulant products to be used either as feed or water additives to boost immunity and increase the resistance of fish and shrimp against the challenging pathogens. Probiotics, prebiotics, synbiotics, phytobiotics, herbal extracts, microalgae, macroalgae, and essential oils have been extensively evaluated. Brown seaweeds (Phaeophyceae) are a large group of multi-cellular macroalgae that are widely distributed in marine aquatic environments. They are abundant in several bioactive sulfated polysaccharides known as fucoidan (FCD). Research studies demonstrated the beneficial functions of FCD in human medicine because of its immunomodulating, antioxidant, anti-allergic, antitumor, antiviral, anti-inflammatory, and hepatoprotective effects. In aquaculture, several researchers have tested the benefits and potential applications of FCD in aquafeed. This literature review provides an updated information and key references of research studies that focused principally on using FCD in aquaculture. Its effects on growth, intestinal health, antioxidant capacity, and immune responses of several finfish and shellfish species will be discussed. This review paper will also highlight the potential efficacy and mechanisms of FCD in the modulation of toxicity signs and increasing the resistance of fish and shrimp against bacterial and viral infections. Hence, this contribution will be valuable to maintain aquaculture sustainability and to improve the health and welfare of farmed fish and shrimp.

Seaweeds as Ingredients to Lower Glycemic Potency of Cereal Foods Synergistically-A Perspective

Seaweeds are traditional food ingredients mainly in seaside regions. Modern food science and nutrition researchers have identified seaweed as a source of functional nutrients, such as dietary soluble and insoluble fibers, proteins, omega-3 fatty acids, prebiotic polysaccharides, polyphenols, and carotenoids. Owing to the rich nutrients, seaweeds and seaweed extract can be used as functional ingredients by modifying the nutrients composition to reduce the proportion of available carbohydrates, delaying the gastric emptying time and the absorption rate of glucose by increasing the digesta viscosity, and attenuating the digesting rate by blocking the activity of digestive enzymes. This review presents the concept of using seaweed as unconventional ingredients that can function synergistically to reduce the glycemic potency of cereal products.

Inhibitory effects of a low-molecular-weight sulfated fucose-containing saccharide on α-amylase and α-glucosidase prepared from ascophyllan

To find natural and safe anti-diabetic foods or potential drugs, low-molecular-weight saccharide fragments LMWAs-H (M_w 33.48 kDa) and LMWAs-L (M_w 6.71 kDa) from the sulfated polysaccharide ascophyllan of Ascophyllum nodosum using alginate lyase (EC 4.2.2.3) were investigated. The results revealed that LMWAs-H possessed potent inhibition activity against α-glucosidase or α-amylase in a concentration-dependent manner, which were higher than native ascophyllan or LMWAs-L. LMWAs-H exhibited a stronger inhibitory activity against α-glucosidase than α-amylase because it differently affects the conformational structures of these enzymes. Structural analysis revealed LMWAs-H to be →4)-α-L-Fucp-(1 → 4)-α-L-Fucp-(1 → 3)-β-D-Xylp-(1 → 3)-α-L-Fucp4S(1→ as main chain, and T-α-D-Glcp-(1→ and →3)-β-D-ManpA_red residues were attached to the ends of main chain as non-reducing- and reducing-end residues, respectively. The 4-deoxy-L-erythro-hex-4-enuronosyluronate linked the O-4 position of →3,4)-β-D-ManpA_red residue as side branches. Our results suggest that LMWAs-H is the main active structural motif responsible for the enzymes-inhibiting activities, which is probably derived from the fucose-containing branches of ascophyllan. Our findings reveal that the strong inhibition of LMWAs-H on α-glucosidase but mild inhibition on α-amylase is highly related to its structural properties, suggesting its desirable characteristics as an anti-diabetic agent.

Antidiabetic potential of seaweed and their bioactive compounds: a review of developments in last decade

Diabetes Mellitus is a public health problem worldwide due to high morbidity and mortality rate associated with it. Diabetes can be managed by synthetic hypoglycemic drugs, although their persistent uses have several side effects. Hence, there is a paradigm shift toward the use of natural products having antidiabetic potential. Seaweeds, large marine benthic algae, are an affluent source of various bioactive compounds, including phytochemicals and antioxidants thus exhibiting various health promoting properties. Seaweed extracts and its bioactive compounds have antidiabetic potential as they inhibit carbohydrate hydrolyzing enzymes in vitro and exhibit blood glucose lowering effect in random and post prandial blood glucose tests in vivo. In addition, they have been associated with reduced weight gain in animals probably by decreasing mRNA expression of pro-inflammatory cytokines with concomitant increase in mRNA expression levels of anti-inflammatory cytokines. Their beneficial effect has been seen in serum and hepatic lipid profile and antioxidant enzymes indicating the protective role of seaweeds against free radicals mediated oxidative stress induced hyperglycemia and associated hyperlipidemia. However, the detailed and in-depth studies of seaweeds as whole, their bioactive isolates and their extracts need to be explored further for their health benefits and wide application in food, nutraceutical and pharmaceutical industries.

Therapeutic Potential of Seaweed-Derived Bioactive Compounds for Cardiovascular Disease Treatment

Cardiovascular diseases are closely related to hypertension, type 2 diabetes mellitus, obesity, and hyperlipidemia. Many studies have reported that an unhealthy diet and sedentary lifestyle are critical factors that enhance these diseases. Recently, many bioactive compounds isolated from marine seaweeds have been studied for their benefits in improving human health. In particular, several unique bioactive metabolites such as polyphenols, polysaccharides, peptides, carotene, and sterol are the most effective components responsible for these activities. This review summarizes the current in vitro, in vivo, and clinical studies related to the protective effects of bioactive compounds isolated from seaweeds against cardiovascular disorders, including anti-diabetic, anti-hypertensive, anti-hyperlipidemia, and anti-obesity effects. Therefore, this present review summarizes these concepts and provides a basis for further in-depth research.

Comparative study on the structural characterization and α-glucosidase inhibitory activity of polysaccharide fractions extracted from Sargassum fusiforme at different pH conditions

Sargassum fusiforme polysaccharides (SFPs), including SFP-3-40, SFP-3-60, SFP-3-80, SFP-7-40, SFP-7-60, SFP-7-80, SFP-10-40, SFP-10-60, and SFP-10-80, were extracted at different pH (3, 7, and 10), and then precipitated with graded precipitation of 40%, 60% and 80% (v/v) ethanol solution, respectively. Their physicochemical properties and α-glucosidase inhibitory activity were determined. Results showed that SFPs significantly differed in the contents of total sugar, protein, uronic acid, sulfate, the zeta potential, and molecular weight distribution. SFPs, including SFP-10-40, SFP-10-60, and SFP-10-80, had bigger absolute zeta potential value and higher respective average molecular weight in the same ethanol concentration precipitate. All samples were mainly composed of fucose, glucuronic acid, and mannose with different molar ratios. The extraction pH and precipitation ethanol solution concentration caused little changes in functional groups, but significantly altered surface morphology of SFPs. Congo red test revealed that all polysaccharides were not helical polysaccharides. Rheological measurements indicated that SFPs were pseudoplastic fluids and showed elastic behavior of the gel. Except SFP-3-40 and SFP-3-60, all other samples had a stronger α-glucosidase inhibitory activity than that of acarbose. The inhibition type of SFPs against α-glucosidase varied owing to different extraction pH and precipitation ethyl concentration. This study shows that extraction pH can significantly affect the structure and hypoglycemic activity of SFPs and provide a data support for the scientific use of Sargassum fusiforme in industrial production.

The positive effects and underlying mechanisms of Undaria pinnatifida polysaccharides on type 2 diabetes mellitus in rats

The aim of the current work was to investigate the anti-diabetic effects and underlying mechanisms of Undaria pinnatifida polysaccharides (UPP) based on a type 2 diabetes (T2DM) rat model. The starch loading test showed that UPP administration could reduce blood glucose fluctuations caused by eating. Analysis of diabetic symptoms and biochemical profiles showed that UPP intervention markedly decreased fasting blood glucose level, mitigated insulin resistance, improved glucose tolerance, dyslipidemia and liver and kidney damage in diabetic rats. The 16S rRNA analysis demonstrated that UPP intervention could markedly change the intestinal microflora composition, causing increases in Alistipes, Bacteroides, Christensenellaceae_R-7_group, Desulfovibrio, Muribaculaceae_norank, Ruminococcaceae_UCG-013, and Ruminococcaceae_UCG-014, and a decrease in Escherichia-Shigella. Furthermore, RT-qPCR analysis results clarified that UPP administration distinctly activated the IRS/PI3K/AKT signaling pathway, restrained PEPCK, G-6-Pase and Egr-1 genes, and affected the relative expression of HMGCR and LDLR genes. This study demonstrates that UPP could be applied as an adjuvant agent for the management of T2DM.

A Combination Approach in Inhibiting Type 2 Diabetes-Related Enzymes Using Ecklonia radiata Fucoidan and Acarbose

Although there are chemotherapeutic efforts in place for Type 2 diabetes mellitus (T2DM), there is a need for novel strategies (including natural products) to manage T2DM. Fucoidan, a sulphated polysaccharide was extracted from Ecklonia radiata. The integrity of the fucoidan was confirmed by structural analysis techniques such as FT-IR, NMR and TGA. In addition, the fucoidan was chemically characterised and tested for cell toxicity. The fucoidan was investigated with regards to its potential to inhibit α-amylase and α-glucosidase. The fucoidan was not cytotoxic and inhibited α-glucosidase (IC50 19 µg/mL) more strongly than the standard commercial drug acarbose (IC50 332 µg/mL). However, the fucoidan lacked potency against α-amylase. On the other hand, acarbose was a more potent inhibitor of α-amylase (IC50 of 109 µg/mL) than α-glucosidase. Due to side effects associated with the use of acarbose, a combination approach using acarbose and fucoidan was investigated. The combination showed synergistic inhibition (>70%) of α-glucosidase compared to when the drugs were used alone. The medicinal implication of this synergism is that a regimen with a reduced acarbose dose may be used, thus minimising side effects to the patient, while achieving the desired therapeutic effect for managing T2DM.

Pressurized Hot Liquid Extraction with 15% v/v Glycerol-Water as An Effective Environment-Friendly Process to Obtain Durvillaea incurvata and Lessonia spicata Phlorotannin Extracts with Antioxidant and Antihyperglycemic Potential

Brown seaweed phlorotannins have shown the potential to promote several health benefits. Durvillaea incurvata and Lessonia spicata-species that are widely distributed in central and southern Chile-were investigated to obtain phlorotannin extracts with antioxidant and antihyperglycemic potential. The use of an environmentally friendly and food-grade glycerol-based pressurized hot liquid extraction (PHLE) process (15% v/v glycerol water) was assessed for the first time to obtain phlorotannins. Multiple effects were analyzed, including the effect of the species, harvesting area (Las Cruces and Niebla), and anatomical part (holdfast, stipe, and frond) on the extracts' polyphenol content (TPC), antioxidant capacity (AC), and carbohydrate-hydrolyzing enzyme-α-glucosidase and α-amylase-inhibitory activity. Contaminants, such as mannitol, heavy metals (As, Cd, Pb, Hg, and Sn), and 5-hydroxymethylfurfural (HMF), were also determined. The anatomical part used demonstrated a significant impact on the extracts' TPC and AC, with holdfasts showing the highest values (TPC: 95 ± 24 mg phloroglucinol equivalents/g dry extract; DPPH: 400 ± 140 μmol Trolox equivalents/g dry extract; ORAC: 560 ± 130 μmol TE/g dry extract). Accordingly, holdfast extracts presented the most potent α-glucosidase inhibition, with D. incurvata from Niebla showing an activity equivalent to fifteen times that of acarbose. Only one frond and stipe extract showed significant α-glucosidase inhibitory capacity. No α-amylase inhibition was found in any extract. Although no HMF was detected, potentially hazardous cadmium levels (over the French limit) and substantial mannitol concentrations-reaching up to 50% of the extract dry weight-were found in most seaweed samples and extracts. Therefore, further purification steps are suggested if food or pharmaceutical applications are intended for the seaweed PHLE extracts obtained in this study.

Characterization and hypoglycemic effects of sulfated polysaccharides derived from brown seaweed Undaria pinnatifida

The brown seaweed Undaria pinnatifida polysaccharides show various biological activities, but their hypoglycemic activity and the underlying mechanism remain unclear. Here, three fractions of sulfated polysaccharides Up-3, Up-4, and Up-5 were prepared by microwave-assisted extraction from U. pinnatifida. In vitro assays demonstrated that Up-3 and Up-4 had strong α-glucosidase inhibitory activity, and Up-3, Up-4, and Up-5 could improve the glucose uptake in insulin-resistant HepG2 cells without affecting their viability. In vivo studies indicated Up-3 and Up-4 markedly reduced postprandial blood glucose levels. Up-U (a mixture of Up-3, Up-4, and Up-5), reduced fasting blood glucose levels, increased glucose tolerance and alleviated insulin resistance in HFD/STZ-induced hyperglycemic mice. Histopathological observation and hepatic glycogen measurement showed that Up-U alleviated the damage of the pancreas islet cell, reduced hepatic steatosis, and promoted hepatic glycogen synthesis. These findings suggest that Up-U could alleviate postprandial and HFD/STZ-induced hyperglycemia and was a potential agent for diabetes treatment.

Current developments in the oral drug delivery of fucoidan

Fucoidan is well known to have various biological functions and is often investigated for pharmaceutical applications. Several studies have been conducted on clinical applications of fucoidan in recent years, especially regarding its oral drug delivery. Although fucoidan has shown promising results in various dosage forms, its potential applications as a dietary supplement have been demonstrated, and recent studies show that oral administration of fucoidan is preferred. However, the focus on the oral delivery of fucoidan in recent studies has caused its potency in therapy to be understudied. This review aims to provide results on the promising fucoidan activity by oral administration with in vivo studies. In addition to using it as an active ingredient, the utilization of fucoidan as an excipient in oral drug delivery systems will be discussed. An overview of fucoidan administration by oral delivery in recent promising studies will provide a direction for further investigations in clinical applications, particularly for fucoidan, which has a broad spectrum of bioactive properties.

Fucoidan Structure and Its Impact on Glucose Metabolism: Implications for Diabetes and Cancer Therapy

Fucoidans are complex polysaccharides derived from brown seaweeds which consist of considerable proportions of L-fucose and other monosaccharides, and sulphated ester residues. The search for novel and natural bioproduct drugs (due to toxicity issues associated with chemotherapeutics) has led to the extensive study of fucoidan due to reports of it having several bioactive characteristics. Among other fucoidan bioactivities, antidiabetic and anticancer properties have received the most research attention in the past decade. However, the elucidation of the fucoidan structure and its biological activity is still vague. In addition, research has suggested that there is a link between diabetes and cancer; however, limited data exist where dual chemotherapeutic efforts are elucidated. This review provides an overview of glucose metabolism, which is the central process involved in the progression of both diseases. We also highlight potential therapeutic targets and show the relevance of fucoidan and its derivatives as a candidate for both cancer and diabetes therapy.

Bioactive Metabolites from Marine Algae as Potent Pharmacophores against Oxidative Stress-Associated Human Diseases: A Comprehensive Review

In addition to cancer and diabetes, inflammatory and ROS-related diseases represent one of the major health problems worldwide. Currently, several synthetic drugs are used to reduce oxidative stress; nevertheless, these approaches often have side effects. Therefore, to overcome these issues, the search for alternative therapies has gained importance in recent times. Natural bioactive compounds have represented, and they still do, an important source of drugs with high therapeutic efficacy. In the ''synthetic'' era, terrestrial and aquatic photosynthetic organisms have been shown to be an essential source of natural compounds, some of which might play a leading role in pharmaceutical drug development. Marine organisms constitute nearly half of the worldwide biodiversity. In the marine environment, algae, seaweeds, and seagrasses are the first reported sources of marine natural products for discovering novel pharmacophores. The algal bioactive compounds are a potential source of novel antioxidant and anticancer (through modulation of the cell cycle, metastasis, and apoptosis) compounds. Secondary metabolites in marine Algae, such as phenolic acids, flavonoids, and tannins, could have great therapeutic implications against several diseases. In this context, this review focuses on the diversity of functional compounds extracted from algae and their potential beneficial effects in fighting cancer, diabetes, and inflammatory diseases.

Multifunctional role of fucoidan, sulfated polysaccharides in human health and disease: A journey under the sea in pursuit of potent therapeutic agents

Fucoidan is a complex polysaccharide (molecular weight 10,000-100,000 Da) derived from brown algae which comprises of L-fucose and sulfate groups have potential as therapeutic diligences against several human diseases. The fucoidan has expanded a widespread range of pharmacological properties as an anti-inflammatory, anticoagulant, antiangiogenic, immunomodulatory, anti-adhesive, anticancer, antidiabetic, antiviral and anti-neurodegenerative agents owing to their diverse chemical conformation and potent antioxidant activity. The antioxidant and immunomodulatory activities of the fucoidan contribute towards their disease preventive potency through dynamic modulation of key intracellular signalling pathways, regulation of ROS accumulation, and maintenance of principal cell survival and death pathways. Additionally, it also reduces cancer-associated cachexia. Despite the wide range of therapeutic potency, the fucoidan is heavily regarded as an unexplored plethora of druggable entities in the current situation. The isolation, screening, biological application, pre-clinical, and clinical assessment along with large scale cost-effective production remain a foremost task to be assessed. Moreover, the chemical synthesis of the present bioactive drug with confirmational rearrangement for enhanced availability and bioactivity also need tenacious investigation. Hence, in the present review, we give attention to the source of isolation of fucoidan, their principle strategic deployment in disease prevention, and the mechanistic investigation of how it works to combat different diseases that can be used for future therapeutic intervention.

The Potential of Sulfated Polysaccharides Isolated from the Brown Seaweed Ecklonia maxima in Cosmetics: Antioxidant, Anti-melanogenesis, and Photoprotective Activities

Sulfated polysaccharides prepared from marine algae are potential ingredients in nutraceutical, pharmaceutical, and cosmeceutical industries. In the present study, the antioxidant, anti-melanogenesis, and photoprotective effects of sulfated polysaccharides obtained from Ecklonia maxima (EMC) were investigated to evaluate their potential in cosmetic. EMC was successfully prepared through Celluclast-assisted extraction and ethanol precipitation, and it contained 79.88% of sulfated polysaccharides that with 69.37% carbohydrates and 10.51% sulfate. EMC effectively suppressed 2,2-azobis(2-amidinopropane) hydrochloride (AAPH)-induced oxidative stress in vitro in Vero cells and in vivo in zebrafish. Furthermore, EMC significantly inhibited mushroom tyrosinase and reduced melanin synthesis in alpha-melanocyte-stimulating hormone-stimulated B16F10 cells. In addition, EMC remarkably attenuated photodamage induced by UVB irradiation in vitro in human keratinocytes (HaCaT cells) and in vivo in zebrafish. Furthermore, EMC effectively inhibited wrinkle-related enzymes and improved collagen synthesis in UVB-irradiated human dermal fibroblasts (HDF cells). These results indicate that EMC possesses strong antioxidant, anti-melanogenesis, and photoprotective activities, and suggest that EMC may be an ideal ingredient in the pharmaceutical and cosmeceutical industries.

Advances in the Study of Marine Products with Lipid-Lowering Properties

With twice the number of cancer's deaths, cardiovascular diseases have become the leading cause of death worldwide. Atherosclerosis, in particular, is a progressive, chronic inflammatory cardiovascular disease caused by persistent damage to blood vessels due to elevated cholesterol levels and hyperlipidemia. This condition is characterized by an increase in serum cholesterol, triglycerides, and low-density lipoprotein, and a decrease in high-density lipoprotein. Although existing therapies with hypolipidemic effects can improve the living standards of patients with cardiovascular diseases, the drugs currently used in clinical practice have certain side effects, which insists on the need for the development of new types of drugs with lipid-lowering effects. Some marine-derived substances have proven hypolipidemic activities with fewer side effects and stand as a good alternative for drug development. Recently, there have been thousands of studies on substances with lipid-lowering properties of marine origin, and some are already implemented in clinical practice. Here, we summarize the active components of marine-derived products having a hypolipidemic effect. These active constituents according to their source are divided into algal, animal, plant and microbial and contribute to the development and utilization of marine medicinal products with hypolipidemic effects.