Fucoidans: Downstream Processes and Recent Applications

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.

From Nature to Innovation: The Uncharted Potential of Natural Deep Eutectic Solvents

This review discusses the significance of natural deep eutectic solvents (NaDESs) as a promising green extraction technology. It employs the consolidated meta-analytic approach theory methodology, using the Web of Science and Scopus databases to analyze 2091 articles as the basis of the review. This review explores NaDESs by examining their properties, challenges, and limitations. It underscores the broad applications of NaDESs, some of which remain unexplored, with a focus on their roles as solvents and preservatives. NaDESs' connections with nanocarriers and their use in the food, cosmetics, and pharmaceutical sectors are highlighted. This article suggests that biomimicry could inspire researchers to develop technologies that are less harmful to the human body by emulating natural processes. This approach challenges the notion that green science is inferior. This review presents numerous successful studies and applications of NaDESs, concluding that they represent a viable and promising avenue for research in the field of green chemistry.

Chemical Composition, Antioxidant, and Antitumor Activity of Fucoidan from the Brown Alga Dictyota dichotoma

Brown macroalgae are a rich source of fucoidans with many pharmacological uses. This research aimed to isolate and characterize fucoidan from Dictyota dichotoma var. dichotoma (Hudson) J.V. Lamouroux and evaluate in vitro its antioxidant and antitumor potential. The fucoidan yield was 0.057 g/g algal dry wt with a molecular weight of about 48.6 kDa. In terms of fucoidan composition, the sulfate, uronic acid, and protein contents were 83.3 ± 5.20 mg/g fucoidan, 22.5 ± 0.80 mg/g fucoidan, and 26.1 ± 1.70 mg/g fucoidan, respectively. Fucose was the primary sugar component, as were glucose, galactose, mannose, xylose, and glucuronic acid. Fucoidan exhibited strong antioxidant potential that increased by more than 3 times with the increase in concentration from 0.1 to 5.0 mg/mL. Moreover, different concentrations of fucoidan (0.05-1 mg/mL) showed their ability to decrease the viability of Ehrlich ascites carcinoma cells in a time-dependent manner. These findings provided a fast method to obtain an appreciable amount of natural fucoidan with established structural characteristics as a promising compound with pronounced antioxidant and anticancer activity.

Fucoidan, a brown seaweed polysaccharide in nanodrug delivery

Fucoidan-a sulfated marine seaweed obtained from brown algae-has raised considerable interest in the scientific community over the last decade as it possesses a wide range of biological activities such as antioxidant, antiviral, anti-inflammatory, anticoagulant, antithrombotic, anticarcinogenic, and immunoregulatory. This polysaccharide finds application as a drug delivery vehicle due to its non-cytotoxicity, biocompatibility, and biodegradability. Besides, nano biomedical systems have used this marine alga for diagnostic and therapeutic purposes. Fucoidan has been extensively studied for use in regenerative medicines, in wound healing, and for sustained drug delivery due to its large biodiversity, cost-effectiveness, and mild procedures for extraction and purification. However, the main concern that limits its application is the variance in its batch-to-batch extraction owing to species type, harvesting, and climatic factors. The current review encloses a compendious overview of the origin, chemical structure, and physicochemical and biological properties of fucoidan and its significant role in nanodrug delivery systems. Special emphasis is given to the recent advances in the use of native/modified fucoidan, its combination with chitosan and metal ions for nanodrug delivery applications, especially in cancer treatment. Additionally, use of fucoidan in human clinical trials as a complementary therapeutic agent is also reviewed.

Fabrication of polyethyleneimine functionalized magnetite nanoparticles for recyclable recovery of fucoidan from aqueous solution

Fucoidan is a kind of natural water-soluble fucose-rich sulfated polysaccharide with promising applications in the food and pharmaceutical industry. However, the traditional methods for fucoidan recovery from aqueous solution are expensive, time-consuming, and environmentally unfriendly. In this work, polyethyleneimine functionalized magnetite nanoparticles (PEI-MNPs) with well-defined core-shell structures were prepared by a Layer-by-Layer (LbL) approach using sodium tripolyphosphate (STPP) as a cross-linker. The as-prepared PEI-MNPs showed improved adsorption capability towards fucoidan at pH 4-8 due to the high density of cationic groups on the surfaces and the absence of internal pores. It was found that the adsorption process of fucoidan onto PEI-MNPs can reach to equilibrium in 50 min at room temperature. The maximum qe derived from the Langmuir isotherm at room temperature was 169.1 mg per g at a pH of 7. A selective fucoidan capture over a model protein BSA can be realized by adjusting pH (6-8) and salt concentration (0.5-2.5 M). The PEI-MNPs loading with fucoidan can be isolated from the final products by a neodymium magnet and regenerated by 4 M NaCl solution as stripping reagent. Therefore, this novel kind of PEI-MNP could be a promising candidate for highly efficient and recyclable recovery of fucoidan from an aqueous solution.

Impact of Enzymatically Extracted High Molecular Weight Fucoidan on Lipopolysaccharide-Induced Endothelial Activation and Leukocyte Adhesion

The endothelial cell lining creates an interface between circulating blood and adjoining tissue and forms one of the most critical barriers and targets for therapeutical intervention. Recent studies suggest that fucoidans, sulfated and fucose-rich polysaccharides from brown seaweed, show multiple promising biological effects, including anti-inflammatory properties. However, their biological activity is determined by chemical characteristics such as molecular weight, sulfation degree, and molecular structure, which vary depending on the source, species, and harvesting and isolation method. In this study, we investigated the impact of high molecular weight (HMW) fucoidan extract on endothelial cell activation and interaction with primary monocytes (MNCs) in lipopolysaccharide (LPS)-induced inflammation. Gentle enzyme-assisted extraction combined with fractionation by ion exchange chromatography resulted in well-defined and pure fucoidan fractions. FE_F3, with a molecular weight ranging from 110 to 800 kDa and a sulfate content of 39%, was chosen for further investigation of its anti-inflammatory potential. We observed that along with higher purity of fucoidan fractions, the inflammatory response in endothelial mono- and co-cultures with MNCs was reduced in a dose-dependent manner when testing two different concentrations. This was demonstrated by a decrease in IL-6 and ICAM-1 on gene and protein levels and a reduced gene expression of TLR-4, GSK3β and NF-kB. Expression of selectins and, consequently, the adhesion of monocytes to the endothelial monolayer was reduced after fucoidan treatment. These data indicate that the anti-inflammatory effect of fucoidans increases with their purity and suggest that fucoidans might be useful in limiting the inflammatory response of endothelial cells in cases of LPS-induced bacterial infection.

Optimization of Extraction of Phlorotannins from the Arctic Fucus vesiculosus Using Natural Deep Eutectic Solvents and Their HPLC Profiling with Tandem High-Resolution Mass Spectrometry

Phlorotannins are secondary metabolites produced mainly by brown seaweeds (Phaeophyceae) and belong to the class of polyphenolic compounds with diverse bioactivities. The key factors in the extraction of polyphenols are the selection of a suitable solvent, method of extraction and selection of optimal conditions. Ultrasonic-assisted extraction (UAE) is one of the advanced energy-saving methods suitable for the extraction of labile compounds. Methanol, acetone, ethanol and ethyl acetate are the most commonly used solvents for polyphenol extraction. As alternatives to toxic organic solvents, a new class of green solvents, natural deep eutectic solvents (NADES), has been proposed for the efficient extraction of a wide range of natural compounds including polyphenols. Several NADES were screened previously for the extraction of phlorotannins; however, the extraction conditions were not optimized and chemical profiling of NADES extract was not performed. The purpose of this work was to study the effect of selected extraction parameters on the phlorotannin content in NADES extract from Fucus vesiculosus, optimization of extraction conditions and chemical profiling of phlorotannins in the NADES extract. A fast and green NADES-UAE procedure was developed for the extraction of phlorotannins. Optimization was performed through an experimental design and showed that NADES (lactic acid:choline chloride; 3:1) provides a high yield (137.3 mg phloroglucinol equivalents per g dry weight of algae) of phlorotannins under the following extraction conditions: extraction time 23 min, 30.0% water concentration and 1:12 sample to solvent ratio. The antioxidant activity of the optimized NADES extract was equal to that of EtOH extract. In total, 32 phlorotannins have been identified (one trimer, two tetramers, six pentamers, four hexamers, six heptamers, six octamers and seven nonamers) in NADES extracts from arctic F. vesiculosus using the HPLC-HRMS and MS/MS technique. It was noted that all the above-mentioned phlorotannins were identified in both EtOH and NADES extracts. Our results suggest that NADES could be considered as an alternative to the conventional techniques for the effective extraction of phlorotannins from F. vesiculosus with high antioxidant potential.

Anti-inflammatory properties of antiangiogenic fucoidan in retinal pigment epithelium cells

Age-related macular degeneration (AMD) is a multifactorial disease in which angiogenesis, oxidative stress and inflammation are important contributing factors. In this study, we investigated the anti-inflammatory effects of a fucoidan from the brown algae Fucus vesiculosus (FV) in primary porcine RPE cells. Inflammation was induced by lipopolysaccharide (LPS), polyinosinic:polycytidylic acid (Poly I:C), Pam2CSK4 (Pam), or tumor necrosis factor alpha (TNF-α). Cell viability was tested with thiazolyl blue tetrazolium bromide (MTT) test, barrier function by measuring transepithelial electric resistance (TEER), interleukin 6 (IL-6) and interleukin 8 (IL-8) secretion in ELISA, retinal pigment epithelium-specific 65 kDa protein (RPE65) and protectin (CD59) expression in Western blot, gene expression with quantitative polymerase chain reaction (qPCR) (IL6, IL8, MERTK, PIK3CA), and phagocytotic activity in a microscopic assay. FV fucoidan did not influence RPE cell viability. FV fucoidan reduced the Poly I:C proinflammatory cytokine secretion of IL-6 and IL-8. In addition, it decreased the expression of IL-6 and IL-8 in RT-PCR. LPS and TNF-α reduced the expression of CD59 in Western blot, this reduction was lost under FV fucoidan treatment. Also, LPS and TNF-α reduced the expression of visual cycle protein RPE65, this reduction was again lost under FV fucoidan treatment. Furthermore, the significant reduction of barrier function after Poly I:C stimulation is ameliorated by FV fucoidan. Concerning phagocytosis, however, the inflammation-induced reduction was not improved by FV fucoidan. FV and proinflammatory milieu did not relevantly influence phagocytosis relevant gene expression either. In conclusion, we show that fucoidan from FV can reduce proinflammatory stimulation in RPE induced by toll-like receptor 3 (TLR-3) activation and is of high interest as a potential compound for early AMD treatment.

Hybrid gelatin-sulfated alginate scaffolds as dermal substitutes can dramatically accelerate healing of full-thickness diabetic wounds

Diabetic foot ulcers (DFUs) are defined as chronic and non-healing wounds that cause skin disorders. Here, we introduce a novel biodegradable gelatin/sulfated alginate hybrid scaffold as a dermal substitute to accelerate the healing of full-thickness diabetic ulcers in a diabetic mouse model. The hybrid scaffold possessing different weight ratios of sulfated alginate, from 10 % up to 50 %, were prepared through chemical crosslinking by carbodiimide chemistry and further freeze-drying. Based on the in vitro cytotoxicity experiments, the hybrid scaffolds not only showed no cytotoxicity, but the cell growth also dramatically increased by increasing the sulfated alginate content. Finally, the pathology of hybrid scaffolds as the dermal substitutes for healing of full-thickness diabetic wounds showed the more appropriate formation of epidermal layer, more homogeneous distribution of collagenous tissue and lower penetration of immune cells for the hybrid scaffolds-treated wounds.

Characterization and Cytotoxic Activity of Microwave-Assisted Extracted Crude Fucoidans from Different Brown Seaweeds

Microwave-assisted extraction (MAE) is recognized as a green method for extraction of natural products. The current research aimed to explore the MAE for fucoidans extraction from different brown seaweeds, including Fucus vesiculosus, F. spiralis, and Laminaria saccharina. Following several solvent-extraction pre-treatment steps and MAE optimization, the algal biomasses were extracted in a ratio of 1:25 in 0.1 M HCl containing 2 M CaCl2 for 1.0 min. The results showed that L. saccharina's extract was different from the others, regarding the highest sugar content reached 0.47 mg glucose equivalent/mg extract being confirmed by monosaccharide composition analysis and the lowest fucoidan content and sulfation degree at 0.09 mg/mg extract and 0.13, respectively. Moreover, these findings were confirmed by tentative structural elucidation based on Fourier-transform infrared spectrometry which also showed a different spectrum. However, the MAE enhanced melanoidins formation in products, which was confirmed by the intense band at 1420 cm-1. Interestingly, the results of monomeric composition showed that fucoidan extract by MAE from F. vesiculosus belonged to sulfated galactofucans which are known for their potential bioactivities. Furthermore, the cytotoxic activity of the four fucoidans in concentrations ranging from 4.9 µg/mL to 2500 µg/mL was investigated and correlated with the chemical characterization showing that F. vesiculosus_MAE fucoidan was the most potent and safest. The current research revealed the chemical heterogeneity of fucoidans regarding taxonomical class and used greener extraction method of fucoidans toward the achievement of the UN sustainability goals.

Sulfated Galactans from Gracilaria fisheri with Supplementation of Octanoyl Promote Wound Healing Activity In Vitro and In Vivo

Sulfated galactans (SG) isolated from Gracilaria fisheri is partially degraded (DSG), and subsequentially supplemented with octanoyl (DSGO) and sulfate (DSGS) groups. The molecular weights of DSG, DSGO, and DSGS are 7.87, 152.79, and 97.07 kDa, respectively. The modification is confirmed using FTIR and NMR, while in vitro wound healing activity is assessed using scratched wound fibroblasts. The results reveal that DSGO exhibits highest percentage of wound closure in scratched fibroblast L929 cells. Furthermore, DSGO is able to promote proliferation and accelerate migration of scratched fibroblasts, which correspond to the regulation of proteins and mRNA (Ki67, p-FAK, vimentin, and E-cadherin) determined by Western blotting and qPCR analysis. The superior wound healing activity of DSGO is also confirmed in excision wound of rats. The results demonstrate that DSGO significantly enhances the percentage of wound closure, re-epithelialization, and collagen arrangement, increases α-smoth muscle actin (α-SMA) and vimentin expression, and decreases that of tumor necrosis factor-α (TNF-α) at the wound site. The results suggest that degraded SG supplemented with medium-chain fatty acids of octanoyl group may pass through the membrane, subsequently activating the mediators associated with proliferation and migration of fibroblasts, which can potentially lead to the promotion of wound healing activity.

Insight into Fucoidan-Based PEGylated PLGA Nanoparticles Encapsulating Methyl Anthranilic Acid: In Vitro Evaluation and In Vivo Anti-Inflammatory Study

A potential fucoidan-based PEGylated PLGA nanoparticles (NPs) offering a proper delivery of N-methyl anthranilic acid (MA, a model of hydrophobic anti-inflammatory drug) have been developed via the formation of fucoidan aqueous coating surrounding PEGylated PLGA NPs. The optimum formulation (FuP2) composed of fucoidan:m-PEG-PLGA (1:0.5 w/w) with particle size (365 ± 20.76 nm), zeta potential (-22.30 ± 2.56 mV), % entrapment efficiency (85.45 ± 7.41), drug loading (51.36 ± 4.75 µg/mg of NPs), % initial burst (47.91 ± 5.89), and % cumulative release (102.79 ± 6.89) has been further investigated for the anti-inflammatory in vivo study. This effect of FuP2 was assessed in rats' carrageenan-induced acute inflammation model. The average weight of the paw edema was significantly lowered (p ≤ 0.05) by treatment with FuP2. Moreover, cyclooxygenase-2 and tumor necrosis factor-alpha immunostaining were decreased in FuP2 treated group compared to the other groups. The levels of prostaglandin E2, nitric oxide, and malondialdehyde were significantly reduced (p ≤ 0.05) in the FuP2-treated group. A significant reduction (p ≤ 0.05) in the expression of interleukins (IL-1β and IL-6) with an improvement of the histological findings of the paw tissues was observed in the FuP2-treated group. Thus, fucoidan-based PEGylated PLGA-MA NPs are a promising anti-inflammatory delivery system that can be applied for other similar drugs potentiating their pharmacological and pharmacokinetic properties.

Preparation of Fucoxanthin Nanoemulsion Stabilized by Natural Emulsifiers: Fucoidan, Sodium Caseinate, and Gum Arabic

This study was proposed to investigate the possibility of O/W nanoemulsion stabilization via natural emulsifiers as a delivery system for fucoxanthin. Nanoemulsions were prepared using ultrasonic treatment (150 W, amplitude 80%, 10 min) with different levels (0.5%, 1%, and 2% wt) of fucoidan, gum Arabic, and sodium caseinate as natural emulsifires and they were compared with tween 80. Then, the creaming index, stability, encapsulation efficacy, Fourier-transform infrared (FT-IR) spectroscopy, and in vitro release were evaluated. The best stability and lowest creaming index were observed at 2% wt of emulsifiers. Nanoemulsions with droplet sizes (113.27−127.50 nm) and zeta potentials (−32.27 to −58.87 mV) were prepared. The droplet size of nanoemulsions was reduced by increasing the emulsifier concentration, and the best nanoemulsion stability after 15 days of storage was in the following order: tween 80 > sodium caseinate > fucoidan > gum Arabic. The encapsulation efficacy of nanoemulsions stabilized by sodium caseinate, fucoidan, and gum Arabic were 88.51 ± 0.11%, 79.32 ± 0.09%, and 60.34 ± 0.13%, respectively. The in vitro gastrointestinal fucoxanthin release of nanoemulsion stabilized with tween 80, sodium caseinate, fucoidan, and gum Arabic were 85.14 ± 0.16%, 76.91 ± 0.34%, 71.41 ± 0.14%, and 68.98 ± 0.36%, respectively. The release of fucoxanthin from nanoemulsions followed Fickian diffusion. The FTIR also confirmed the encapsulation of fucoxanthin.

Fucoidan from Marine Macroalgae: Biological Actions and Applications in Regenerative Medicine, Drug Delivery Systems and Food Industry

The marine macroalgae produce a collection of bioactive polysaccharides, of which the sulfated heteropolysaccharide fucoidan produced by brown algae of the class Phaeophyceae has received worldwide attention because of its particular biological actions that confer nutritional and health benefits to humans and animals. The biological actions of fucoidan are determined by their structure and chemical composition, which are largely influenced by the geographical location, harvest season, extraction process, etc. This review discusses the structure, chemical composition and physicochemical properties of fucoidan. The biological action of fucoidan and its applications for human health, tissue engineering, regenerative medicine and drug delivery are also addressed. The industrial scenario and prospects of research depicted would give an insight into developing fucoidan as a commercially viable and sustainable bioactive material in the nutritional and pharmacological sectors.

Sulfated Galactofucans: An Outstanding Class of Fucoidans with Promising Bioactivities

Fucoidans encompass versatile and heterogeneous sulfated biopolysaccharides of marine origin, specifically brown algae and marine invertebrates. Their chemistry and bioactivities have been extensively investigated in the last few decades. The reported studies revealed diverse chemical skeletons in which l-fucose is the main sugar monomer. However, other sugars, i.e., galactose, mannose, etc., have been identified to be interspersed, forming several heteropolymers, including galactofucans/fucogalactans (G-fucoidans). Particularly, sulfated galactofucans are associated with rich chemistry contributing to more promising bioactivities than fucans and other marine polysaccharides. The previous reports in the last 20 years showed that G-fucoidans derived from Undaria pinnatifida were the most studied; 21 bioactivities were investigated, especially antitumor and antiviral activities, and unique biomedical applications compared to other marine polysaccharides were demonstrated. Hence, the current article specifically reviews the biogenic sources, chemistry, and outstanding bioactivities of G-fucoidans providing the opportunity to discover novel drug candidates.

Antiviral Polymers: A Review

Polymers, due to their high molecular weight, tunable architecture, functionality, and buffering effect for endosomal escape, possess unique properties as a carrier or prophylactic agent in preventing pandemic outbreak of new viruses. Polymers are used as a carrier to reduce the minimum required dose, bioavailability, and therapeutic effectiveness of antiviral agents. Polymers are also used as multifunctional nanomaterials to, directly or indirectly, inhibit viral infections. Multifunctional polymers can interact directly with envelope glycoproteins on the viral surface to block fusion and entry of the virus in the host cell. Polymers can indirectly mobilize the immune system by activating macrophages and natural killer cells against the invading virus. This review covers natural and synthetic polymers that possess antiviral activity, their mechanism of action, and the effect of material properties like chemical composition, molecular weight, functional groups, and charge density on antiviral activity. Natural polymers like carrageenan, chitosan, fucoidan, and phosphorothioate oligonucleotides, and synthetic polymers like dendrimers and sialylated polymers are reviewed. This review discusses the steps in the viral replication cycle from binding to cell surface receptors to viral-cell fusion, replication, assembly, and release of the virus from the host cell that antiviral polymers interfere with to block viral infections.

Systematic comparison of eight methods for preparation of high purity sulfated fucans extracted from the brown alga Pelvetia canaliculata

Sulfated fucans from brown algae are a heterogeneous group of biologically active molecules. To learn more on their structure and to analyze and exploit their biological activities, there is a growing need to develop reliable and cost effective protocols for their preparation. In the present study, a brown alga Pelvetia canaliculata (Linnaeus) was used as a rich source of sulfated fucans. Sulfated fucan preparation methods included neutral and acidic extractions followed by purification with activated charcoal (AC), polyvinylpolypyrrolidone (PVPP), or cetylpyridinium chloride (CPC). Final products were compared in terms of yield, purity, monosaccharide composition and molecular weight. Acidic extractions provided higher yields compared to neutral ones, whereas the AC purification provided sulfated fucan products with the highest purity. Mass spectrometry analyses were done on oligosaccharides produced by the fucanase MfFcnA from the marine bacterium Mariniflexille fucanivorans. This has provided unique insight into enzyme specificity and the structural characteristics of sulfated fucans.

Anti-Inflammatory Mechanisms of Fucoidans to Treat Inflammatory Diseases: A Review

Fucoidans are sulfated heteropolysaccharides found in the cell walls of brown seaweeds (Phaeophyceae) and in some marine invertebrates. Generally, fucoidans are composed of significant amounts of L-fucose and sulfate groups, and lesser amounts of arabinose, galactose, glucose, glucuronic acid, mannose, rhamnose, and xylose. In recent years, fucoidans isolated from brown seaweeds have gained considerable attention owing to their promising bioactive properties such as antioxidant, immunomodulatory, anti-inflammatory, antiobesity, antidiabetic, and anticancer properties. Inflammation is a complex immune response that protects the organs from infection and tissue injury. While controlled inflammatory responses are beneficial to the host, leading to the removal of immunostimulants from the host tissues and restoration of structural and physiological functions in the host tissues, chronic inflammatory responses are often associated with the pathogenesis of tumor development, arthritis, cardiovascular diseases, diabetes, obesity, and neurodegenerative diseases. In this review, the authors mainly discuss the studies since 2016 that have reported anti-inflammatory properties of fucoidans isolated from various brown seaweeds, and their potential as a novel functional material for the treatment of inflammatory diseases.

Efficacy of Natural Deep Eutectic Solvents for Extraction of Hydrophilic and Lipophilic Compounds from Fucus vesiculosus

The impact of the composition of natural deep eutectic solvents (NADES) and extraction conditions on the simultaneous extraction of hydrophilic ascorbic acid (AA), phlorotannins (TPhC), and lipophilic fucoxanthin (FX) from Fucus vesiculosus was investigated for the first time. In biological tests, the NADES extracts showed the promising ability to scavenge DPPH radicals. A positive correlation was observed between DPPH scavenging activity and AA, TPhC, and FX contents. We calculate the synergistic effect of antioxidants extracted by NADES from F. vesiculosus based on the mixture effect (ME). The addition of 30% water to the NADES and the prolongation of sonication time from 20 min up to 60 min were favorable for the ME. The ME for extracts with the NADES was increased by two folds (ME > 2). In contrast, conventional extraction by maceration with steering at 60 °C does not lead to the synergistic effect (ME = 1). It is notable that the NADES provides high stability and preserves the antioxidant activity of the extracts from F. vesiculosus during storage.

Controlled sulfation of mixed-linkage glucan by Response Surface Methodology for the development of biologically applicable polysaccharides

Endogenous and exogenous sulfated polysaccharides exhibit potent biological activities, including inhibiting blood coagulation and protein interactions. Controlled chemical sulfation of alternative polysaccharides holds promise to overcome limited availability and heterogeneity of naturally sulfated polysaccharides. Here, we established reaction parameters for the controlled sulfation of the abundant cereal polysaccharide, mixed-linkage β(1,3)/β(1,4)-glucan (MLG), using Box-Behnken Design of Experiments (BBD) and Response Surface Methodology (RSM). The optimization of the degree-of-substitution (DS) was externally validated through the production of sulfated MLGs (S-MLGs) with observed DS and M_w values deviating less than 20% and 30% from the targeted values, respectively. Simultaneous optimization of DS and M_w resulted in the same range of deviation from the targeted value. S-MLGs with DS > 1 demonstrated a modest anticoagulation effect versus heparin, and a greater P-selectin affinity than fucoidan. As such, this work provides a route to medically important polymers from an economical agricultural polysaccharide.

Fucoidans as Scientifically and Commercially Important Algal Polysaccharides

As a highly bioactive seaweed substance with many promising physiological activities, fucoidan has attracted attention from many industries all over the world [...].

The Therapeutic Potential of the Anticancer Activity of Fucoidan: Current Advances and Hurdles

Several types of cancers share cellular and molecular behaviors. Although many chemotherapy drugs have been designed to weaken the defenses of cancer cells, these drugs may also have cytotoxic effects on healthy tissues. Fucoidan, a sulfated fucose-based polysaccharide from brown algae, has gained much attention as an antitumor drug owing to its anticancer effects against multiple cancer types. Among the anticancer mechanisms of fucoidan are cell cycle arrest, apoptosis evocation, and stimulation of cytotoxic natural killer cells and macrophages. Fucoidan also protects against toxicity associated with chemotherapeutic drugs and radiation-induced damage. The synergistic effect of fucoidan with existing anticancer drugs has prompted researchers to explore its therapeutic potential. This review compiles the mechanisms through which fucoidan slows tumor growth, kills cancer cells, and interacts with cancer chemotherapy drugs. The obstacles involved in developing fucoidan as an anticancer agent are also discussed in this review.

Whole Alga, Algal Extracts, and Compounds as Ingredients of Functional Foods: Composition and Action Mechanism Relationships in the Prevention and Treatment of Type-2 Diabetes Mellitus

Type-2 diabetes mellitus (T2DM) is a major systemic disease which involves impaired pancreatic function and currently affects half a billion people worldwide. Diet is considered the cornerstone to reduce incidence and prevalence of this disease. Algae contains fiber, polyphenols, ω-3 PUFAs, and bioactive molecules with potential antidiabetic activity. This review delves into the applications of algae and their components in T2DM, as well as to ascertain the mechanism involved (e.g., glucose absorption, lipids metabolism, antioxidant properties, etc.). PubMed, and Google Scholar databases were used. Papers in which whole alga, algal extracts, or their isolated compounds were studied in in vitro conditions, T2DM experimental models, and humans were selected and discussed. This review also focuses on meat matrices or protein concentrate-based products in which different types of alga were included, aimed to modulate carbohydrate digestion and absorption, blood glucose, gastrointestinal neurohormones secretion, glycosylation products, and insulin resistance. As microbiota dysbiosis in T2DM and metabolic alterations in different organs are related, the review also delves on the effects of several bioactive algal compounds on the colon/microbiota-liver-pancreas-brain axis. As the responses to therapeutic diets vary dramatically among individuals due to genetic components, it seems a priority to identify major gene polymorphisms affecting potential positive effects of algal compounds on T2DM treatment.

Valorization and extraction optimization of Citrus seeds for food and functional food applications

Valorization of food byproducts has attracted recently considerable attention. Citrus fruits provide considerable non-edible residues reach 80% in juice production. They are considered agri-wastes to comprise peel, pulp and seeds. Previous investigations have focused on peel and pulp to recover value-added products. The review presents for the first-time phytochemical composition of Citrus seeds' products, i.e., oil and extracts. Fatty acids, phytosterols and tocopherols amounted as the major bioactives in Citrus seeds, in addition to limonoids, dietary fibers and flavonoids. Besides their nutritional values, these chemicals have promising applications including production of biodiesel, food enhancers and antioxidants, especially from mandarin and grapefruit seeds. Optimum conditions of the different Citrus seeds' valorization are discussed to improve extraction yield and lessen environmental hazards of solvent extraction. This review presents the best utilization practices for one of the largest cultivated fruit seeds worldwide and its different applications.

Bioproduction of biomacromolecules for antiviral applications

The societal damage brought on by viral epidemics indicates that next-generation antiviral treatments must be developed and deployed. Biomacromolecules are a diverse class of compounds that can potentially exhibit potent antiviral activity. Their efficacy and mechanisms of action are dependent upon multiple structural factors, including molecular weight, degree and position of sulfation, and backbone stereochemistry. Extracting biomacromolecules from animals and plants for healthcare applications is undesirable, as these methods are unable to yield products with well-defined chemical structures. Modern advances utilizing recombinant microbes and metabolic pathway engineering can be a key step towards large-scale bioproduction of tailored biomacromolecules for targeted antiviral applications.

A Review on Molecular Mechanisms and Patents of Marine-derived Anti-thrombotic Agents

Thrombosis is a condition of major concern worldwide as it is associated with life-threatening diseases related to the cardiovascular system. The condition affects 1 in 1000 adults annually, whereas 1 in 4 dies due to thrombosis, and this increases as the age group increases. The major outcomes are considered to be a recurrence, bleeding due to commercially available anti-coagulants, and deaths. The side effects associated with available anti-thrombotic drugs are a point of concern. Therefore, it is necessary to discover and develop an improvised benefit-risk profile drug, therefore, in search of alternative therapy for the treatment of thrombosis, marine sources have been used as promising treatment agents. They have shown the presence of sulfated fucans/galactans, fibrinolytic proteases, diterpenes, glycosaminoglycan, glycoside, peptides, amino acids, sterols, polysaccharides, polyphenols, vitamins, and minerals. Out of these marine sources, many chemicals were found to have anti-thrombotic activities. This review focuses on the recent discovery of anti-thrombotic agents obtained from marine algae, sponges, mussels, and sea cucumber, along with their mechanism of action and patents on its extraction process, preparation methods, and their applications. Further, the article concludes with the author's insight related to marine drugs, which have a promising future.

Structure and Biological Activity Analysis of Fucoidan Isolated from Sargassum siliquosum

Fucoidans are heterologous polysaccharides commonly seen in brown macroalgae and are known for their biological activity including anticancer, antiangiogenic, immunomodulation, and antiviral properties. The brown macroalga Sargassum siliquosum was used for the extraction and analysis of fucoidan in this study. The S. siliquosum fucoidan was indicated as a galactofucoidan composed of sugars, uronate, and sulfate at a ratio of 12:1:4 and its purity was 85% based on the abovementioned three major components. Structural analysis by electrospray ionization collision-induced dissociation tandem mass spectroscopy revealed that the purified fucoidan consisted of a carbohydrate chain composed of (1→3)-linked or (1→4)-linked l-fucose residues, with sulfate groups at C-2 and C-4 positions. Galactose residues with (1→4)-linkages function as the branch points and they are located at the C-3 or C-4 position of fucose residues. Galactose residues are sulfated mainly at C-4 and C-6, while some sulfation can also be seen at C-2. The fucoidan purified from S. siliquosum demonstrated antioxidant, anti-inflammatory, and antilipogenic activities.

Synthesis, Characterization, and Catalytic Properties of Magnetic Fe3O4@FU: A Heterogeneous Nanostructured Mesoporous Bio-Based Catalyst for the Synthesis of Imidazole Derivatives

In this protocol, Fucoidan (FU), a fucose-rich sulfated polysaccharide extracted from brown algae Fucus vesiculosus was used for in situ preparation of magnetic Fe₃O₄@FU. Nanoco magnetic properties of Fe₃O₄@FU were investigated by energy dispersive X-ray (EDX) spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) adsorption method, and vibrating sample magnetometer (VSM). The catalytic activity of Fe₃O₄@FU was employed for the synthesis of tri- and tetra-substituted imidazoles through three- and four-component reactions respectively, between benzyl, aldehydes, NH₄OAc and benzyl, aldehydes, NH₄OAc, and amine under reflux in ethanol. It is worth nothing that excellent yields, short reaction times, chromatography-free purification, and environmental friendliness are highlighted features of this protocol.

Fucoidan Characterization: Determination of Purity and Physicochemical and Chemical Properties

Fucoidans are marine sulfated biopolysaccharides that have heterogenous and complicated chemical structures. Various sugar monomers, glycosidic linkages, molecular masses, branching sites, and sulfate ester pattern and content are involved within their backbones. Additionally, sources, downstream processes, and geographical and seasonal factors show potential effects on fucoidan structural characteristics. These characteristics are documented to be highly related to fucoidan potential activities. Therefore, numerous chemical qualitative and quantitative determinations and structural elucidation methods are conducted to characterize fucoidans regarding their physicochemical and chemical features. Characterization of fucoidan polymers is considered a bottleneck for further biological and industrial applications. Consequently, the obtained results may be related to different activities, which could be improved afterward by further functional modifications. The current article highlights the different spectrometric and nonspectrometric methods applied for the characterization of native fucoidans, including degree of purity, sugar monomeric composition, sulfation pattern and content, molecular mass, and glycosidic linkages.

The Development of Hyaluronan/Fucoidan-Based Nanoparticles as Macrophages Targeting an Epigallocatechin-3-Gallate Delivery System

The aim of this study was to develop a macrophage-targeted nanoparticle composed of hyaluronan/fucoidan complexes with polyethylene glycol-gelatin to encapsulate and deliver epigallocatechin-3-gallate (EGCG), a compound that can regulate macrophage activation and pro-inflammatory mediator production. We show that our nanoparticles can successfully bond to macrophages and deliver more EGCG than an EGCG solution treatment, confirming the anti-inflammatory effects of these nanoparticles in lipopolysaccharide-stimulated macrophages. The prepared nanoparticles were established with a small mean particle size (217.00 ± 14.00 nm), an acceptable polydispersity index (0.28 ± 0.07), an acceptable zeta potential value (-33.60 ± 1.30 mV), and a high EGCG loading efficiency (52.08% ± 5.37%). The targeting abilities of CD44 binding were increased as the hyaluronan concentration increased and decreased by adding a competitor CD44 antibody. Moreover, we found that fucoidan treatment significantly reduced macrophage migration after lipopolysaccharide treatment in a dose-responsive manner. In summary, we successfully created macrophage-targeted nanoparticles for effective targeted delivery of EGCG, which should aid in the development of future anti-inflammatory drugs against macrophage-related diseases.

Sulfated Polysaccharides from Marine Algae as a Basis of Modern Biotechnologies for Creating Wound Dressings: Current Achievements and Future Prospects

Wound healing involves a complex cascade of cellular, molecular, and biochemical responses and signaling processes. It consists of successive interrelated phases, the duration of which depends on a multitude of factors. Wound treatment is a major healthcare issue that can be resolved by the development of effective and affordable wound dressings based on natural materials and biologically active substances. The proper use of modern wound dressings can significantly accelerate wound healing with minimum scar mark. Sulfated polysaccharides from seaweeds, with their unique structures and biological properties, as well as with a high potential to be used in various wound treatment methods, now undoubtedly play a major role in innovative biotechnologies of modern natural interactive dressings. These natural biopolymers are a novel and promising biologically active source for designing wound dressings based on alginates, fucoidans, carrageenans, and ulvans, which serve as active and effective therapeutic tools. The goal of this review is to summarize available information about the modern wound dressing technologies based on seaweed-derived polysaccharides, including those successfully implemented in commercial products, with a focus on promising and innovative designs. Future perspectives for the use of marine-derived biopolymers necessitate summarizing and analyzing results of numerous experiments and clinical trial data, developing a scientifically substantiated approach to wound treatment, and suggesting relevant practical recommendations.

Seaweed's Bioactive Candidate Compounds to Food Industry and Global Food Security

The world population is continuously growing, so it is important to keep producing food in a sustainable way, especially in a way that is nutritious and in a sufficient quantity to overcome global needs. Seaweed grows, and can be cultivated, in seawater and generally does not compete for arable land and freshwater. Thus, the coastal areas of the planet are the most suitable for seaweed production, which can be an alternative to traditional agriculture and can thus contribute to a reduced carbon footprint. There are evolving studies that characterize seaweed's nutritional value and policies that recognize them as food, and identify the potential benefits and negative factors that may be produced or accumulated by seaweed, which are, or can be, dangerous for human health. Seaweeds have a high nutritional value along with a low caloric input and with the presence of fibers, proteins, omega 3 and 6 unsaturated fatty acids, vitamins, and minerals. Moreover, several seaweed sub-products have interesting features to the food industry. Therefore, the focus of this review is in the performance of seaweed as a potential alternative and as a safe food source. Here described is the nutritional value and concerns relating to seaweed consumption, and also how seaweed-derived compounds are already commercially explored and available in the food industry and the usage restrictions to safeguard them as safe food additives for human consumption.

Mechanisms of Bioactivities of Fucoidan from the Brown Seaweed Fucus vesiculosus L. of the Barents Sea

The aim of this study was to elucidate some mechanisms of radical scavenging and the anti-inflammatory, anti-hyperglycemic, and anti-coagulant bioactivities of high molecular weight fucoidan from Fucus vesiculosus in several in vitro models. Fucoidan has displayed potent 1, 1-diphenyl-2-picryl hydrazil radical scavenging and reduction power activities. It significantly inhibits the cyclooxygenase-2 (COX-2) enzyme (IC₅₀ 4.3 μg mL⁻¹) with a greater selectivity index (lg(IC₈₀ COX-2/IC₈₀COX-1), −1.55) than the synthetic non-steroidal anti-inflammatory drug indomethacin (lg(IC₈₀ COX-2/IC₈₀COX-1), −0.09). A concentration-dependent inhibition of hyaluronidase enzyme with an IC₅₀ of 2.9 μg mL⁻¹ was observed. Fucoidan attenuated the lipopolysaccharide-induced expression of mitogen-activated protein kinase p38. Our findings suggest that the inhibition of dipeptidyl peptidase-IV (DPP-IV) (IC₅₀ 1.11 μg mL⁻¹) is one of the possible mechanisms involved in the anti-hyperglycemic activity of fucoidan. At a concentration of 3.2 μg mL⁻¹, fucoidan prolongs the activated partial thromboplastin time and thrombin time by 1.5-fold and 2.5-fold compared with a control, respectively. A significant increase of prothrombin time was observed after the concentration of fucoidan was increased above 80 μg mL⁻¹. This evidenced that fucoidan may have an effect on intrinsic/common pathways and little effect on the extrinsic mechanism. This study sheds light on the multiple pathways of the bioactivities of fucoidan. As far as we know, the inhibition of hyaluronidase and DPP-IV by high molecular fucoidan was studied for the first time in this work. Our results and literature data suggest that molecular weight, sulfate content, fucose content, and polyphenols may contribute to these activities. It seems that high molecular weight fucoidan has promising therapeutic applications in different pharmacological settings. Anti-oxidant, anti-inflammatory and anti-coagulant drugs have been used for the management of complications of COVID19. Taken as a whole, fucoidan could be considered as a prospective candidate for the treatment of patients with COVID19; however, additional research in this field is required.