Antioxidant and anti-inflammatory activities of porphyran isolated from discolored nori (Porphyra yezoensis)

Pyropia yezoensis Extract Attenuates Osteoarthritis Progression In Vitro and In Vivo

Osteoarthritis (OA), a degenerative disease characterized by cartilage degradation and inflammation, occurs due to trauma caused by external stimuli or cartilage aging. Pyropia yezoensis is a red alga that belongs to the Porphyra family and is consumed as food in Asia, especially Korea, Japan, and China. P. yezoensis contains various bioactive substances, including carotenoids, flavonoids, and vitamins, that exert anti-inflammatory, antioxidant, and anti-photoaging effects. In the present study, the anti-osteoarthritic effects of 30% fermented alcohol extract of P. yezoensis (30% FEPY) on interleukin-1 beta (IL-1β)-stimulated chondrocytes and a destabilization of the medial meniscus (DMM)-induced OA rat model were investigated. The results showed that pretreatment with 30% FEPY significantly reduced the IL-1β-induced expression of inflammatory factors (e.g., inducible nitric oxide synthase and cyclooxygenase-2) and cartilage-degrading enzymes [matrix metalloproteinase (MMP) 1, MMP3, MMP13, a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) 4, and ADAMTS5], which was analyzed using Griess reaction, enzyme-linked immunosorbent assay, and Western blot analysis. The anti-osteoarthritic effects of 30% FEPY, which were mediated through mitogen-activated protein kinase and nuclear factor kappa-light-chain-enhancer of activated B cell signaling, were analyzed using Western blot analysis. In an in vivo study, Safranin O staining and immunohistochemistry analysis revealed that treatment with 30% FEPY significantly increased cartilage degradation and collagen type II protein expression in the DMM group. These findings collectively suggest that 30% FEPY is a promising candidate for alleviating OA progression and developing new therapeutic drugs.

The Multifaceted Applications of Seaweed and Its Derived Compounds in Biomedicine and Nutraceuticals: A Promising Resource for Future

The increasing demand for global food resources and over-dependence on terrestrial agroecosystems pose a significant challenge to the sustainable production of food commodities. Macroalgae are an essential source of food production in the marine environment, and their cultivation is a promising approach to alleviate the impending global food insecurity due to key factors, such as independence from terrestrial agriculture, rapid growth rate, unique biochemical composition, and carbon capture potential. Moreover, in many countries, seaweed has been used as food for decades because of its health and nutritional benefits. Seaweed contains bioactive components that are beneficial against various pathological conditions, including cancer, type 2 diabetes, and neurological disorders. Furthermore, the natural products derived from macroalgae have also been found to have immunostimulatory and antimicrobial properties. Macroalgae are also a significant source of rare sugars such as L-fucose, L-rhamnose, and glucuronic acid. Besides sugars, other bioactive components have been widely reported for their potential in cosmeceuticals. We have outlined the nutrient composition and functional properties of different species of macroalgae, with an emphasis on their potential as value-added products to the functional food market. Beyond being nutritional powerhouses, the variety of biological activities in human health and biomedicine makes them excellent candidates for developing novel drugs. Therefore, this review summarizes the pharmaceutical applications of macroalgae and suggests potential strategies for incorporating macroalgae-derived bioactive compounds into therapeutic products.

The potential of seaweed-derived polysaccharides as sustainable biostimulants in agriculture

Seaweed polysaccharides such as alginate, carrageenan, agar, and ulvan are emerging as key bioresources in sustainable agriculture due to their unique structural characteristics and functional properties. This review highlights their potential as eco-friendly biostimulants capable of enhancing soil health, plant growth, and stress resilience. Specific mechanisms, including the gel-forming capacity of alginate, ion exchange abilities, and the hydrophilic nature of these polysaccharides, enable improved water retention, nutrient uptake, and plant productivity under adverse conditions, including drought, salinity, and extreme temperatures. Moreover, their role as hydrogels and bio-elicitors introduces novel approaches to addressing global challenges in agriculture, such as climate change and food security. Real-world applications, such as the use of Ascophyllum nodosum extract for drought tolerance and Gracilaria tenuistipitata var. liui to boost grain yields, underscore the practicality and success of these biostimulants. Despite their promising applications, challenges like variability in seaweed quality, high extraction costs, and limited product standardization hinder their scalability. This review provides an integrated analysis of their biochemical properties, agricultural applications, and commercial products while proposing solutions to optimize their use for advancing sustainable farming practices.

Marine algal polysaccharides: Multifunctional bioactive ingredients for cosmetic formulations

Marine algal polysaccharides (MAP) are increasingly recognized as versatile bioactive ingredients in cosmetics due to their wide-ranging therapeutic benefits and eco-friendly sourcing. Sourced from red, brown, and green algae, these polysaccharides deliver numerous advantages for skin health, including antioxidant, anti-inflammatory, anti-aging, hydrating, and regenerative properties. As demand for natural and sustainable products grows, MAP offer a renewable and environmentally responsible alternative to synthetic chemicals. This review examines the chemical structures, extraction methods, biological activities, and cosmetic applications of key MAP, such as carrageenans, alginates, fucoidans, laminaran, ulvan, and sulfated rhamnan. It also discusses emerging research trends, innovative extraction techniques, and the formulation of multifunctional products that combine these polysaccharides with other bioactive compounds. As consumer preferences increasingly lean toward ethical and sustainable choices, MAP are well-positioned to contribute to the development of high-performance cosmetic products that meet both industry standards and consumer expectations.

Structural Determination and Functional Residues Analysis of a CBM99 Family Carbohydrate-Binding Module Targeting Porphyran

Porphyran is a bioactive polysaccharide extensively distributed in algae of the genus Porphyra. Carbohydrate-binding modules (CBMs) are independent domains often found in carbohydrate-active enzymes that function to bind carbohydrates and have various applications. Only one porphyran-binding CBM has been hitherto structurally characterized. The founding member (FvCBM99) of the CBM99 family was previously shown to exhibit a specific binding capacity to the primary constituent units of porphyran. In this study, the structure of FvCBM99 was determined at 1.75 Å resolution by X-ray crystallography. The protein adopts an overall β-sandwich fold with two antiparallel β-sheets comprising 7 β-strands. Site-directed mutagenesis analysis confirmed that residues W44, W49, K83, R87, and W93 are indispensable for the interaction of FvCBM99 with porphyran. The work delivers the first structural insights into the CBM99 family, which can guide the practical applications of FvCBM99 and promote the future discovery and characterization of porphyran-binding proteins.

Immunomodulatory functions of algal bioactive compounds

Algae, a crucial constituent of marine systems, serve an indispensable function as primary producers, supporting the marine food web, contributing to carbon sequestration, and providing habitats that sustain biodiversity. This review focuses on the bioactive constituents of algae, including polysaccharides, polyphenols, polypeptides, and terpenoid compounds, and discusses their potential applications in treating immune-related diseases, as well as the mechanisms through which they modulate immune responses. The bioactive substances derived from algae, including polyphenols, bioactive peptides, terpenes, polysaccharides and other compounds, may play a preventive role by modulating allergic responses and reducing the incidence of inflammation and cancer.

Physiological and Transcriptional Responses to Phosphorus Deficiency and Glucose-6-Phosphate Supplementation in Neopyropia yezoensis

Neopyropia yezoensis, a marine red algae species, has significant economic and ecological value. However, phosphorus (P) deficiency has emerged as a growing concern in many cultivation regions, negatively impacting its growth. To adapt to P deficiency, algae have evolved various strategies, including using dissolved organic phosphorus (DOP) sources to sustain growth. Despite its prevalence as a form of DOP, the utilization mechanism of glucose-6-phosphate (G6P) by N. yezoensis remains unclear. In this study, the physiological and transcriptional responses of N. yezoensis to P deficiency and G6P supplementation were examined. The results demonstrated that prolonged P deficiency significantly inhibited the growth of N. yezoensis and had a negative impact on physiological indicators such as photosynthetic pigments and antioxidant enzyme activity. However, G6P treatment gradually alleviated these adverse effects over time. Both P deficiency and G6P treatment were associated with increased expression of genes involved in signal transduction and P starvation responses while concurrently downregulating genes related to photosynthesis and antioxidant defenses. In contrast, the suppression of gene expression was less significant under G6P treatment. This study elucidates the adaptive strategies of N. yezoensis in response to P deficiency and clarifies the regulatory pathways involved in G6P utilization, providing novel insights into its P nutrient acquisition and metabolic regulation.

Extraction, purification, structural features, and pharmacological properties of polysaccharides from Houttuynia cordata: A review

Houttuynia cordata Thunb, also known as "Chinese medicine antibiotic", is a medicine food homology plant. It has functions of clearing heat, eliminating toxins, in folk medicine. The extraction purification and bioactivity of Houttuynia cordata polysaccharides (HCPs) have been of wide interest to researchers in recent years studies. Studies have confirmed that HCPs exhibit various biofunctionalities, such as anti-inflammatory, antiviral, antibacterial, antioxidant, immunomodulatory, regulation of gut microbiota, and gut-lung axis, as well as anti-radiation, and anti-cancer properties. Therefore, a comprehensive systematic review is needed to summarize the recent advances of HCPs and facilitate a better understanding of their biofunctionalities. This paper reviews the research progress of HCPs in extraction and purification methods, chemical structures, biological activities, possible mechanisms of action, and potential application prospects, which can provide some valuable insights and updated information for their further development and application of HCPs in the fields of therapeutic agents, functional foods, cosmetics, animal feeds.

Extraction, structural features, and pharmacological effects of the polysaccharides from Porphyra yezoensis: A review

Porphyra yezoensis, an important medicinal seaweed extensively cultivated and consumed in China, Japan, and South Korea, is traditionally considered a precious healthy food and food additive. Published studies showed that the polysaccharides are major bioactive macromolecules from P. yezoensis with great potential for the development of nutraceuticals and functional foods. As an important component of P. yezoensis, P. yezoensis polysaccharide (PYP) is mainly extracted by hot water extraction, ultrasonic-assisted extraction, and microwave-assisted extraction methods. Subsequently obtained by decolorization, deproteinization, removal of other small molecules, and separation on various chromatographic columns. The main structural components of PYP were (1 → 3)-linked β-D-galactose and (1 → 4)-linked 3,6-anhydro-α-L-galactose. Accumulating evidence has revealed that PYP has diverse biological activities, such as antioxidant, suppressing kidney stones, immunomodulatory, etc. This review systematically summarizes the recent preparation progress, chemical structures, bioactivities, and the underlying mechanisms of PYP. Information from this review provides insights into the further development of PYP as therapeutic agents and functional foods. Although there have been extensive studies on PYP, there are gaps in establishing quality standard, toxicological research, clinical application and other aspects. To enhance the utility of P. yezoensis, it is necessary to strengthen the research on these aspects.

The application of marine polysaccharides to antitumor nanocarriers

Nanotechnology has revolutionized the diagnosis, monitoring and treatment of biomedical diseases, in which nanocarriers have greatly improved the targeting and bioavailability of antitumor drugs. The marine natural polysaccharides fucoidan, chitosan, alginate, carrageenan and porphyran have broad-spectrum bioactivities and unique physicochemical properties such as excellent non-toxicity, biocompatibility, biodegradability and reproducibility, which have placed them as a principal focus in the nanocarrier field. Nanocarriers based on different types of marine polysaccharides are distinctive in addressing antitumor therapeutic challenges such as targeting, environmental responsiveness, drug resistance, tissue toxicity, enhancing diagnostic imaging, overcoming the first-pass effect and innovative 3D binding. Additionally, they all share the possibility of relatively easy chemical modification, while their separation into well-defined derivatives provide innovative structure-activity relationship possibilities. Liposomes, nanoparticles and polymer-micelles constructed from them can efficiently deliver drugs such as paclitaxel, gemcitabine, siRNA and others, which are widely used in radiotherapy, chemotherapy, immunotherapy, nucleic acid therapy and photothermal therapy, yet there are still infinite possibilities for innovation and exploration. This article reviews the recent advances and challenges of marine polysaccharide-based delivery systems as oncology drug nanocarriers.

Recent biotechnological applications of value-added bioactive compounds from microalgae and seaweeds

Microalgae and seaweed have been consumed as food for several decades to combat starvation and food shortages worldwide. The most famous edible microalgae species are Nostoc, Spirulina, and Aphanizomenon, in addition to seaweeds, which are used in traditional medicine and food, such as Nori, which is one of the most popular foods containing Pyropia alga as a major ingredient. Recently, many applications use algae-derived polysaccharides such as agar, alginate, carrageenan, cellulose, fucoidan, mannan, laminarin, ulvan, and xylan as gelling agents in food, pharmaceuticals, and cosmetics industries. Moreover, pigments (carotenoids particularly astaxanthins, chlorophylls, and phycobilins), minerals, vitamins, polyunsaturated fatty acids, peptides, proteins, polyphenols, and diterpenes compounds are accumulated under specific cultivation and stress conditions in the algal cells to be harvested and their biomass used as a feedstock for the relevant industries and applications. No less critical is the use of algae in bioremediation, thus contributing significantly to environmental sustainability.This review will explore and discuss the various applications of microalgae and seaweeds, emphasising their role in bioremediation, recent products with algal added-value compounds that are now on the market, and novel under-developing applications such as bioplastics and nanoparticle production. Nonetheless, special attention is also drawn towards the limitations of these applications and the technologies applied, and how they may be overcome.

A review: Structure, bioactivity and potential application of algal polysaccharides in skin aging care and therapy

Skin is the first barrier of body which stands guard for defending aggressive pathogens and environmental pressures all the time. Cutaneous metabolism changes in harmful exposure, following with skin dysfunctions and diseases. Lots of researches have reported that polysaccharides extracted from seaweeds exhibited multidimensional bioactivities in dealing with skin disorder. However, few literature systematically reviews them. The aim of the present paper is to summarize structure, bioactivities and structure-function relationship of algal polysaccharides acting on skin. Algal polysaccharides show antioxidant, immunomodulating, hydration regulating, anti-melanogenesis and extracellular matrix (ECM) regulating abilities via multipath ways in skin. These bioactivities are determined by various parameters, including seaweed species, molecular weight, monosaccharides composition and substitute groups. In addition, potential usages of algae-derived polysaccharides in skin care and therapy are also elaborated. Algal polysaccharides are potential ingredients in formulation that providing anti-aging efficacy for skin.

Porphyran Attenuates Neuronal Loss in the Hippocampal CA1 Subregion Induced by Ischemia and Reperfusion in Gerbils by Inhibiting NLRP3 Inflammasome-Mediated Neuroinflammation

Porphyran, a sulfated polysaccharide found in various species of marine red algae, has been demonstrated to exhibit diverse bioactivities, including anti-inflammatory effects. However, the protective effects of porphyran against cerebral ischemia and reperfusion (IR) injury have not been investigated. The aim of this study was to examine the neuroprotective effects of porphyran against brain IR injury and its underlying mechanisms using a gerbil model of transient forebrain ischemia (IR in the forebrain), which results in pyramidal cell (principal neuron) loss in the cornu ammonis 1 (CA1) subregion of the hippocampus on day 4 after IR. Porphyran (25 and 50 mg/kg) was orally administered daily for one week prior to IR. Pretreatment with 50 mg/kg of porphyran, but not 25 mg/kg, significantly attenuated locomotor hyperactivity and protected pyramidal cells located in the CA1 area from IR injury. The pretreatment with 50 mg/kg of porphyran significantly suppressed the IR-induced activation and proliferation of microglia in the CA1 subregion. Additionally, the pretreatment significantly inhibited the overexpressions of nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing protein-3 (NLRP3) inflammasome complex, and pro-inflammatory cytokines (interleukin 1 beta and interleukin 18) induced by IR in the CA1 subregion. Overall, our findings suggest that porphyran exerts neuroprotective effects against brain IR injury, potentially by reducing the reaction (activation) and proliferation of microglia and reducing NLRP3 inflammasome-mediated neuroinflammation.

Characterization and structural identification of a family 16 carbohydrate-binding module (CBM): First structural insights into porphyran-binding CBM

Porphyran is a favorable functional polysaccharide widely distributed in Porphyra. It displays a linear structure majorly constituted by alternating 1,4-linked α-l-galactopyranose-6-sulfate (L6S) and 1,3-linked β-d-galactopyranose (G) units. Carbohydrate-binding modules (CBMs) are desired tools for the investigation and application of polysaccharides, including in situ visualization, on site and specific assay, and functionalization of biomaterials. However, only one porphyran-binding CBM has been hitherto reported, and its structural knowledge is lacking. Herein, a novel CBM16 family domain from a marine bacterium Aquimarina sp. BL5 was discovered and expressed. The recombinant protein AmCBM16 exhibited the desired specificity for porphyran. Bio-layer interferometry assay revealed that the protein binds to porphyran tetrasaccharide (L6S-G)2 with an association constant of 1.3 × 103 M-1. The structure of AmCBM16 was resolved by the X-ray crystallography, which displays a β-sandwich fold with two antiparallel β-sheets constituted by 10 β-strands. Site-directed mutagenesis analysis demonstrated that the residues Gly-30, Trp-31, Lys-88, Lys-123, Phe-125, and Phe-127 play dominant roles in AmCBM16 binding. This study provides the first structural insights into porphyran-binding CBM.

Ultrasound-assisted fermentation of Porphyra yezoensis sauce at different growth stages using Lactiplantibacillus plantarum: Metabolic response and biological activity

This study first employed ultrasonic-assisted fermentation of seaweed foot material with Lactiplantibacillus plantarum to produce Porphyra yezoensis sauce. The aim was to examine L. plantarum's growth and metabolism of nutritional components at different growth stages under low- (133.99 W/L) and high-ultrasonic power densities (169.17 W/L). After 24-h fermentation, L. plantarum exhibited a 21.32 % increase in the sonicated P. yezoensis sauce at 133.99 W/L and the logarithmic growth phase compared to that at 169.17 W/L. In addition, compared to the non-sonicated sauce, total phenolic and flavonoid contents increased by around 58 % and 27 % in sonicated sauce at 133.99 W/L, reaching 92.38 mg GEA/g DW and 111.08 mg RE/g DW, respectively. Principal Component Analysis (PCA) of the evaluation criteria for different fermentation stages under 133.99 W/L power ultrasonication revealed that the P. yezoensis sauce generated more phenolic compounds and exhibited stronger antioxidant capabilities in the sonicated sample at the logarithmic phase of L. plantarum. Compared to the traditional treated P. yezoensis sauce, the content of free amino acids was significantly increased in sonicated sauce, especially for logarithmic phase. Finally, GC-IMS analysis demonstrated that the ultrasonication at logarithmic phase released more volatile compounds compared to the non-sonicated sauce. This led to a reduction in the fishy odour of the Porphyra yezoensis sauce and an improved release of favourable flavour compounds.

Characterization of a novel carbohydrate-binding module specifically binding to the major structural units of porphyran

Porphyran is a promising bioactive polysaccharide majorly composed of 4-linked α-l-galactopyranose-6-sulfate (L6S) and 3-linked β-d-galactopyranose (G) disaccharide repeating units. Carbohydrate-binding modules (CBMs) have been verified to be essential tools for investigating polysaccharides. However, no confirmed CBM binding to porphyran has been hitherto reported. In this study, an unknown domain with a predicted β-sandwich fold from a potential GH86 porphyranase was discovered, and further recombinantly expressed. The CBM protein (named FvCBM99) presented a desired specificity for porphyran tetrasaccharide with an affinity constant of 1.9 × 10-4 M, while it could not bind to agarose tetrasaccharide. The sequence novelty and well-defined function of FvCBM99 and its homologs reveal a new CBM family, CBM99. Besides, the application potential of FvCBM99 in in situ visualization of porphyran was demonstrated. The discovery of FvCBM99 provides a favorable tool for future studies of porphyran.

Sulfated Galactans from Agarophytes: Review of Extraction Methods, Structural Features, and Biological Activities

Agarophytes are important seaweeds of the Rhodophyta type, which have been highly exploited for industrial use as sources of a widely consumed polysaccharide of agar. In addition to that, sulfated galactans (SGs) from agarophytes, which consist of various functional sulfate groups, have attracted the attention of scientists in current studies. SGs possess various biological activities, such as anti-tumor, anticoagulant, anti-inflammatory, antioxidant, anti-obesity, anti-diabetic, anti-microbial, anti-diarrhea, and gut microbiota regulation properties. Meanwhile, the taxonomy, ecological factors, i.e., environmental factors, and harvest period, as well as preparation methods, i.e., the pretreatment, extraction, and purification conditions, have been found to influence the chemical compositions and fine structures of SGs, which have, further, been shown to have an impact on their biological activities. However, the gaps in the knowledge of the properties of SGs due to the above complex factors have hindered their industrial application. The aim of this paper is to collect and systematically review the scientific evidence about SGs and, thus, to pave the way for broader and otherwise valuable industrial applications of agarophytes for human enterprise. In the future, this harvested biomass could be sustainably used not only as a source of agar production but also as natural materials in functional food and pharmaceutical industries.

Enhancing Immunity and Modulating Vaginal Microflora Against Candidal Vaginitis Through Nanoemulsion Supplemented with Porphyra Oligosaccharide as an Intravaginal Vaccine Adjuvant

Background

Intravaginal vaccination is an encouraging approach to prevent infectious vaginitis, with nanoemulsions showing effectiveness as mucosal adjuvants.

Purpose

This study aimed to formulate a nanoemulsion incorporating Porphyra oligosaccharide (PO@NE) and assess its effectiveness as a mucosal adjuvant in intravaginal vaccines against candidal vaginitis.

Materials and Methods

PO@NE was prepared, and the stability, immunomodulatory activity and cytotoxicity were screened in vitro. Further, the preventive effect of PO@NE as adjuvants for heat-killed Candida albicans (HK-CA) vaccines was explored in a murine model of candidal vaginitis, in comparison with those supplemented with polysaccharide (PP@NE). The mice were intravaginally vaccinated with 106 HK-CA cells, suspended in 1% NE without or with either PO or PP at a final concentration of 6.5 μg/mL, in a total volume of 20 μL. This vaccination was intravaginally administered once a week for 3 weeks. One week following the final vaccination, the mice underwent an intravaginal challenge with 107 C. albicans cells. One week after the challenge, the mice were euthanized to isolate serum, spleen, vaginal washes, and vaginal tissues for analysis.

Results

PP@NE and PO@NE, with diameters approximately around 100 nm, exhibited exceptional stability at 4°C and low cytotoxicity when used at a concentration of 1% (v/v). Intravaginal vaccination with HK-CA adjuvanted with PO@NE effectively protected against candidal vaginitis evidenced by less Candida hyphae colonization, milder mucosal damage and cell infiltration. Moreover, enhanced mucosal antibody production, induction of T helper (Th)1 and Th17-related immune responses, enlarged the population of CD8+ cells, and elevated vaginal microflora diversity were observed in vaccinated mice. Interestingly, the potency was rather attenuated when PO@NE was replaced with PP@NE.

Conclusion

These findings indicate PO@NE as a HK-CA vaccine adjuvant for candidal vaginitis prevention via enhancement of both cellular and humoral immunity and modulation of vaginal microflora, emphasizing further intravaginal vaccination development.

The antioxidant activity of polysaccharides: A structure-function relationship overview

Over the last years, polysaccharides have been linked to antioxidant effects using both in vitro chemical and biological models. The reported structures, claimed to act as antioxidants, comprise chitosan, pectic polysaccharides, glucans, mannoproteins, alginates, fucoidans, and many others of all type of biological sources. The structural features linked to the antioxidant action include the polysaccharide charge, molecular weight, and the occurrence of non-carbohydrate substituents. The establishment of structure/function relationships can be, however, biased by secondary phenomena that tailor polysaccharides behavior in antioxidant systems. In this sense, this review confronts some basic concepts of polysaccharides chemistry with the current claim of carbohydrates as antioxidants. It critically discusses how the fine structure and properties of polysaccharides can define polysaccharides as antioxidants. Polysaccharides antioxidant action is highly dependent on their solubility, sugar ring structure, molecular weight, occurrence of positive or negatively charged groups, protein moieties and covalently linked phenolic compounds. However, the occurrence of phenolic compounds and protein as contaminants leads to misleading results in methodologies often used for screening and characterization purposes, as well as in vivo models. Despite falling in the concept of antioxidants, the role of polysaccharides must be well defined according with the matrices where they are involved.

Pyropia yezoensis-derived porphyran attenuates acute and chronic colitis by suppressing dendritic cells

Porphyran is known to inhibit immune cell function. Previously, porphyran was shown to prevent lipopolysaccharide-induced sepsis in mice. However, studies on the inhibitory effects of porphyran during colitis are currently lacking. In this study, we evaluated the effects of Pyropia yezoensis-derived porphyran on dextran sodium sulfate (DSS)-induced acute and chronic colitis. The oral or intraperitoneal administration of porphyran inhibited the progression of DSS-induced colitis in mice, with the former also preventing immune cell infiltration in the colon. The levels of intracellular interferon-γ and interleukin-17 in T cells decreased when porphyran was administered orally. Porphyran inhibited T cell activation by suppressing dendritic cells (DCs) and macrophages. Porphyran prevented pathogen-associated molecular pattern and damage-associated molecular pattern-dependent DC and macrophage activation. Finally, porphyran attenuated chronic colitis caused via the long-term administration of DSS. These findings indicate that the oral administration of porphyran can inhibit DSS-induced colitis by suppressing DC and macrophage activation.

Seaweed-Derived Sulfated Polysaccharides; The New Age Chemopreventives: A Comprehensive Review

Seaweed-derived bioactive compounds are regularly employed to treat human diseases. Sulfated polysaccharides are potent chemotherapeutic or chemopreventive medications since it has been discovered. They have exhibited anti-cancer properties by enhancing immunity and driving apoptosis. Through dynamic modulation of critical intracellular signalling pathways, such as control of ROS generation and preservation of essential cell survival and death processes, sulfated polysaccharides' antioxidant and immunomodulatory potentials contribute to their disease-preventive effectiveness. Sulfated polysaccharides provide low cytotoxicity and good efficacy therapeutic outcomes via dynamic modulation of apoptosis in cancer. Understanding how sulfated polysaccharides affect human cancer cells and their molecular involvement in cell death pathways will showcase a new way of chemoprevention. In this review, the significance of apoptosis and autophagy-modulating sulfated polysaccharides has been emphasized, as well as the future direction of enhanced nano-formulation for greater clinical efficacy. Moreover, this review focuses on the recent findings about the possible mechanisms of chemotherapeutic use of sulfated polysaccharides, their potential as anti-cancer drugs, and proposed mechanisms of action to drive apoptosis in diverse malignancies. Because of their unique physicochemical and biological properties, sulfated polysaccharides are ideal for their bioactive ingredients, which can improve function and application in disease. However, there is a gap in the literature regarding the physicochemical properties and functionalities of sulfated polysaccharides and the use of sulfated polysaccharide-based delivery systems in functional cancer. Furthermore, the preclinical and clinical trials will reveal the drug's efficacy in cancer.

Freshness Analysis of Raw Laver (Pyropia yenzoensis) Conserved under Supercooling Conditions

Freezing raw laver is unsuitable for the laver industry due to process characteristics and economic problems. Therefore, this study attempted to investigate supercooled storage to extend the storage period without freezing, rather than refrigeration. To compare and analyze the storage ability of supercooling, the experiment was performed under refrigeration (5 °C), constant supercooling (CS, -2 °C), stepwise supercooling (SS, -2 °C), and freezing (-18 °C) conditions for 15 days, and the physicochemical changes according to the treatment and period were investigated. All SS samples, which were designed for stable supercooling, were kept in a supercooled state for 15 days. Two samples among the twelve total subjected to CS were frozen. At 9 days, the drip losses of the CS and SS samples were 6.32% and 6.48%, respectively, which was two times lower than that of refrigeration and three times lower than that of the frozen samples. The VBN of the refrigerated samples was 108.33 mg/100 g at 6 days, which exceeded the decomposition criterion. Simultaneously, the VBN of the other treatments was under the decomposition criterion of 30 mg/100 g. However, the VBN of both supercooling samples at 15 days increased to higher than the decomposition criterion. Regarding appearance, the refrigerated samples showed tissue destruction at 9 days, but tissue destruction of the CS and CC samples was observed at 15 days, and tissue destruction of the frozen samples was not observed until 15 days. Consequently, supercooling did not maintain quality for longer periods than freezing, but it did extend the shelf life more than refrigeration, and effectively preserved the quality for a short period.

Rhodophyta as Potential Sources of Photoprotectants, Antiphotoaging Compounds, and Hydrogels for Cosmeceutical Application

Seaweeds are macroscopic, multicellular, eukaryotic and photosynthetic organisms, and are a source of chemical diversity with powerful biological activities for diversified industrial applications including cosmeceuticals. Red seaweeds (Rhodophyta) are good sources of Mycosporine-like amino acids (MAA) for photoprotectant and antiphotoaging compounds. In addition, Rhodophyta are also good sources for hydrogel compounds that are used widely in the food, pharmaceutical and cosmeceutical industries as gelling agents, moisturizers or for their antiphotoaging effects. Our survey and ongoing studies revealed that the biodiversity of Indonesian Rhodophyta is rich and is a treasure trove for cosmeceutical agents including MAA and hydrogels. This study delivers valuable information for identifying potential red seaweeds in screening and searching for cosmeceutical agents.

Effect of the harvest period on the structure and anti-allergic activity of Porphyra haitanensis polysaccharides

Polysaccharides are a major functional component of seaweeds with various biological activities. Porphyra haitanensis is usually harvested in different growth periods, but how the harvest periods influence the Porphyra haitanensis polysaccharide (PHP) activity is unclear. This work aimed to evaluate the anti-allergic activity of PHP from different harvest periods and investigate the potential structure-activity relationship. The water-soluble polysaccharide of P. haitanensis from three different harvest periods was purified and administered to an ovalbumin-sensitized food allergy mouse model. Results showed that PHPs significantly alleviated the allergic symptoms and reduced the production of histamine and allergen-specific IgE. Further experiments elucidated that PHPs suppressed the allergic activity of intestinal epithelial cells, dendritic cells, and Th2 cells and downregulated the proportion of Th2 cells. Noticeably, the molecular weight and sulfate content gradually decreased as the harvest period was delayed; simultaneously, the anti-allergic activity gradually increased, implying a relationship between the harvest period, structure, and anti-allergic activity of PHPs. This work elucidated the anti-allergic activity of PHPs from different harvest periods, facilitated the deep-processing and efficient application of Porphyra haitanensis, and shed light on the development of novel anti-allergic functional foods.

Natural Products from Plants and Algae for Treatment of Alzheimer’s Disease: A Review

Neurodegenerative disorders including Parkinson’s disease (PD), Huntington’s disease (HD) and the most frequent, Alzheimer’s disease (AD), represent one of the most urgent medical needs worldwide. Despite a significantly developed understanding of disease development and pathology, treatments that stop AD progression are not yet available. The recent approval of sodium oligomannate (GV-971) for AD treatment in China emphasized the potential value of natural products for the treatment of neurodegenerative disorders. Many current clinical studies include the administration of a natural compound as a single and combination treatment. The most prominent mechanisms of action are anti-inflammatory and anti-oxidative activities, thus preserving cellular survival. Here, we review current natural products that are either approved or are in testing for a treatment of neurodegeneration in AD. In addition to the most important compounds of plant origin, we also put special emphasis on compounds from algae, given their neuroprotective activity and their underlying mechanisms of neuroprotection.

Anti-inflammatory, anti-infectious and anti-cancer potential of marine algae and sponge: A review

Marine organisms are potentially a pretty good source of highly bioactive secondary metabolites that are best known for their anti-inflammation, anti-infection, and anti-cancer potential. The growing threat of bacterial resistance to synthetic antibiotics, is a potential source to screen terrestrial and marine natural organisms to discover promising anti-inflammatory and antimicrobial agents which can synergistically overcome the inflammatory and infectious disases. Algae and sponge have been studied enormously to evaluate their medicinal potential to fix variety of diseases, especially inflammation, infections, cancers, and diabetes. Cytarabine is the first isolated biomolecule from marine organism which was successfully practiced in clinical setup as chemotherapeutic agent against xylogenous leukemia both in acute and chronic conditions. This discovery opened the horizon for systematic evaluation of broad range of human disorders. This review is designed to look into the literature reported on anti-inflammatory, anti-infectious, and anti-cancerous potential of algae and sponge to refine the isolated compounds for value addition process.

An Overview of Potential Seaweed-Derived Bioactive Compounds for Pharmaceutical Applications

Nowadays, seaweeds are widely involved in biotechnological applications. Due to the variety of bioactive compounds in their composition, species of phylum Ochrophyta, class Phaeophyceae, phylum Rhodophyta and Chlorophyta are valuable for the food, cosmetic, pharmaceutical and nutraceutical industries. Seaweeds have been consumed as whole food since ancient times and used to treat several diseases, even though the mechanisms of action were unknown. During the last decades, research has demonstrated that those unique compounds express beneficial properties for human health. Each compound has peculiar properties (e.g., antioxidant, antimicrobial, antiviral activities, etc.) that can be exploited to enhance human health. Seaweed's extracted polysaccharides are already involved in the pharmaceutical industry, with the aim of replacing synthetic compounds with components of natural origin. This review aims at a better understanding of the recent uses of algae in drug development, with the scope of replacing synthetic compounds and the multiple biotechnological applications that make up seaweed's potential in industrial companies. Further research is needed to better understand the mechanisms of action of seaweed's compounds and to embrace the use of seaweeds in pharmaceutical companies and other applications, with the final scope being to produce sustainable and healthier products.

Antiviral Activities of Algal-Based Sulfated Polysaccharides

An antiviral agent is urgently needed based on the high probability of the emergence and re-emergence of future viral disease, highlighted by the recent global COVID-19 pandemic. The emergence may be seen in the discovery of the Alpha, Beta, Gamma, Delta, and recently discovered Omicron variants of SARS-CoV-2. The need for strategies besides testing and isolation, social distancing, and vaccine development is clear. One of the strategies includes searching for an antiviral agent that provides effective results without toxicity, which is well-presented by significant results for carrageenan nasal spray in providing efficacy against human coronavirus-infected patients. As the primary producer of sulfated polysaccharides, marine plants, including macro- and microalgae, offer versatility in culture, production, and post-isolation development in obtaining the needed antiviral agent. Therefore, this review will describe an attempt to highlight the search for practical and safe antiviral agents from algal-based sulfated polysaccharides and to unveil their features for future development.

Ecological and evolutionary diversification of sulphated polysaccharides in diverse photosynthetic lineages: A review

Sulphated polysaccharides (SPs) are carbohydrate macromolecules with sulphate esters that are found among marine algae, seagrasses, mangroves and some terrestrial plants. The sulphate concentration in the ocean (28 mM) since ancient time could have driven the production of SPs in marine algae. SPs have a gelatinous property that can protect marine algae against desiccation and salinity stress. Agar and carrageenan are red algal SPs that are widely used as gelling agents in the food and pharmaceutical industries. The information on the SPs from freshwater and land plants are limited. In this review, we reviewed the taxonomic distribution and composition of SPs in different photosynthetic lineages, and explored the association of SP production in these diversified photosynthetic organisms with evolution history and environmental stresses. We also reviewed the genes/proteins involved in SP biosynthesis. Insights into SP biosynthetic machinery may shed light on the evolution that accompanied adaptation to life on earth.

Development and Characterization of Films for Food Application Incorporating Porphyran Extracted from Porphyra dioica

Non-biodegradable plastic is one of the biggest environmental problems of our lifetime and, considering the present societal needs, it will get worse. Consequently, there is an urgent need to develop sustainable and renewable alternatives to plastic, such as plastic-like materials obtained from biodegradable polymers, namely sulfated polysaccharides, considered one of the most viable alternatives. There is also a need to obtain these materials in an environmentally and economically sustainable way. The hereby developed process of obtaining film-forming solutions from semi-refined porphyran (PorphSR) uses a green solvent (hot water) with a high extraction yield of semi-refined porphyran (26.66 ± 0.27%) in a reproducible way and with low levels of contaminants. The obtained semi-refined porphyran showed good antioxidant potential in all tests performed: HPSA (Δ0.066 ± 0.002), DPPH (2.23 ± 0.78%), FRAP (0.420 ± 0.014 eq. ascorbic acid µg mg−1 of extract) and ABTS (20.46 ± 0.90%). After being cast into films, the most notable antioxidant properties were those of the semi-refined porphyran in the DPPH, FRAP and ABTS assays and of the pectin, (PorphSR_PcT and PorphSR_PcT_Gly) in the HPSA assay. Morphologically, the films showed relatively homogeneous and low roughness surfaces. It is concluded that the described method to obtain semi-refined porphyran is feasible and reproducible, and that the developed films, mainly PorfP2_PcT_Gly, proved to be a potential candidate for non-biodegradable plastic substitutes.

Porphyra yezoensis Sauces Fermented With Lactic Acid Bacteria: Fermentation Properties, Flavor Profile, and Evaluation of Antioxidant Capacity in vitro

The demand for roasted seaweed sandwich (Porphyra yezoensis) product has risen in recent years. The product slicing process has created a huge number of scraps that are not utilized effectively. Three lactic acid bacteria (LAB) strains were used to ferment P. yezoensis sauces in this study, including Lactobacillus fermentum, Lactobacillus casei, Streptococcus thermophilus, and the mixed strains (1:1:1, v/v). The fermentation characteristics, antioxidant capacity in vitro, sensory properties, and flavoring substances of fermented P. yezoensis sauces were analyzed. After 21 days of fermentation, all LAB strains grew well in the P. yezoensis sauces, with protease activity increased to 6.6, 9.24, 5.06, and 5.5 U/mL, respectively. Also, the flavors of P. yezoensis sauces fermented with L. casei and L. fermentum were satisfactory. On this premise, gas chromatography-mass spectrometry (GC-MS) was used to investigate the changes in gustatory compounds in P. yezoensis sauces fermented with L. casei and L. fermentum. In general, 42 and 41 volatile flavor chemicals were identified after the fermentation of L. casei and L. fermentum. Furthermore, the fermented P. yezoensis sauce possessed greater DPPH scavenging activity and ferric-reducing ability power than the unfermented P. yezoensis. Overall, the flavor and taste of P. yezoensis sauce fermented by L. casei was superior.

Bioactive polysaccharides from red seaweed as potent food supplements: a systematic review of their extraction, purification, and biological activities

Most marine macroalgae such as red seaweeds are potential alternative sources of useful bioactive compounds. Beside serving as food source, recent studies have shown that red seaweeds are rich sources of bioactive polysaccharides. Red seaweed polysaccharides (RSPs) have various physiological and biological activities, which allow them to be used as immunomodulators, anti-obesity agents, and prebiotic ingredients. Lack of summary information and human clinical trials on the various polysaccharides from red seaweeds, however limits industrial-scale utilization of RSPs in functional foods. This review summarizes recent information on the approaches used for RSPs extraction and purification, mechanistic investigations of their biological activities, and related molecular principles behind their purported ability to prevent diseases. The information here also provides a theoretical foundation for further research into the structure and mechanism of action of RSPs and their potential applications in functional foods.

Insights on preparation, structure and activities of Gracilaria lemaneiformis polysaccharide

Gracilaria lemaneiformis is a kind of edible economic red algae, which is rich in polysaccharide, phycobiliprotein, pigments, minerals and other nutrients and functional components. Polysaccharide is one of the main active components of Gracilaria lemaneiformis, which has been reported to present various physiological bioactivities, including regulation of glycolipid metabolism, immune, anti-tumor, anti-inflammatory and other biological activities. This paper aims to provide a brief summary of extraction, purification, structural characteristics, and physiological activities of Gracilaria lemaneiformis polysaccharide (GLP). This article is able to provide theoretical basis for the future research and exploitation of GLP, and improve its potential development to promote the healthy and sustainable processing and high value utilization industry of Gracilaria lemaneiformis.

Immunomodulatory effects of polysaccharides from marine algae for treating cancer, infectious disease, and inflammation

A significant rise in the occurrence and severity of adverse reactions to several synthetic drugs has fueled considerable interest in natural product-based therapeutics. In humans and animals, polysaccharides from marine microalgae and seaweeds have immunomodulatory effects. In addition, these polysaccharides may possess antiviral, anticancer, hypoglycemic, anticoagulant, and antioxidant properties. During inflammatory diseases, such as autoimmune diseases and sepsis, immunosuppressive molecules can serve as therapeutic agents. Similarly, molecules that participate in immune activation can induce immune responses against cancer and infectious diseases. We aim to discuss the chemical composition of the algal polysaccharides, namely alginate, fucoidan, ascophyllan, and porphyran. We also summarize their applications in the treatment of cancer, infectious disease, and inflammation. Recent applications of nanoparticles that are based on algal polysaccharides for the treatment of cancer and inflammatory diseases have also been addressed. In conclusion, these applications of marine algal polysaccharides could provide novel therapeutic alternatives for several diseases.

Applying Seaweed Compounds in Cosmetics, Cosmeceuticals and Nutricosmetics

The interest in seaweeds for cosmetic, cosmeceutics, and nutricosmetics is increasing based on the demand for natural ingredients. Seaweeds offer advantages in relation to their renewable character, wide distribution, and the richness and versatility of their valuable bioactive compounds, which can be used as ingredients, as additives, and as active agents in the formulation of skin care products. Bioactive compounds, such as polyphenols, polysaccharides, proteins, peptides, amino acids, lipids, vitamins, and minerals, are responsible for the biological properties associated with seaweeds. Seaweed fractions can also offer technical features, such as thickening, gelling, emulsifying, texturizing, or moistening to develop cohesive matrices. Furthermore, the possibility of valorizing industrial waste streams and algal blooms makes them an attractive, low cost, raw and renewable material. This review presents an updated summary of the activities of different seaweed compounds and fractions based on scientific and patent literature.

Potential Antiviral Properties of Industrially Important Marine Algal Polysaccharides and Their Significance in Fighting a Future Viral Pandemic

Over the decades, the world has witnessed diverse virus associated pandemics. The significant inhibitory effects of marine sulfated polysaccharides against SARS-CoV-2 shows its therapeutic potential in future biomedical applications and drug development. Algal polysaccharides exhibited significant role in antimicrobial, antitumor, antioxidative, antiviral, anticoagulant, antihepatotoxic and immunomodulating activities. Owing to their health benefits, the sulfated polysaccharides from marine algae are a great deal of interest globally. Algal polysaccharides such as agar, alginate, carrageenans, porphyran, fucoidan, laminaran and ulvans are investigated for their nutraceutical potential at different stages of infection processes, structural diversity, complexity and mechanism of action. In this review, we focus on the recent antiviral studies of the marine algae-based polysaccharides and their potential towards antiviral medicines.

Porphyran-derived oligosaccharides alleviate NAFLD and related cecal microbiota dysbiosis in mice

Porphyran and its derivatives possess a variety of biological activities, such as ameliorations of oxidative stress, inflammation, hyperlipemia, and immune deficiencies. In this study, we evaluated the potential efficacy of porphyran-derived oligosaccharides from Porphyra yezoensis (PYOs) in alleviating nonalcoholic fatty liver disease (NAFLD) and preliminarily clarified the underlying mechanism. NAFLD was induced by a high-fat diet for six months in C57BL/6J mice, followed by treatment with PYOs (100 or 300 mg/kg/d) for another six weeks. We found that PYOs reduced hepatic oxidative stress in mice with NAFLD, which plays a critical role in the occurrence and development of NAFLD. In addition, PYOs could markedly decrease lipid accumulation in liver by activating the IRS-1/AKT/GSK-3β signaling pathway and the AMPK signaling pathway in mice with NAFLD. PYOs also apparently relieved the hepatic fibrosis induced by oxidative stress via downregulation of TGF-β and its related proteins, so that liver injury was markedly alleviated. Furthermore, PYOs treatment relieved cecal microbiota dysbiosis (such as increasing the relative abundance of Akkermansia, while decreasing the Helicobacter abundance), which could alleviate oxidative stress, inflammation, and lipid metabolism, and protect the liver to a certain degree. In summary, PYOs treatment remarkably improved NAFLD via a specific molecular mechanism and reshaped the cecal microbiota.

Seaweed Components as Potential Modulators of the Gut Microbiota

Macroalgae, or seaweeds, are a rich source of components which may exert beneficial effects on the mammalian gut microbiota through the enhancement of bacterial diversity and abundance. An imbalance of gut bacteria has been linked to the development of disorders such as inflammatory bowel disease, immunodeficiency, hypertension, type-2-diabetes, obesity, and cancer. This review outlines current knowledge from in vitro and in vivo studies concerning the potential therapeutic application of seaweed-derived polysaccharides, polyphenols and peptides to modulate the gut microbiota through diet. Polysaccharides such as fucoidan, laminarin, alginate, ulvan and porphyran are unique to seaweeds. Several studies have shown their potential to act as prebiotics and to positively modulate the gut microbiota. Prebiotics enhance bacterial populations and often their production of short chain fatty acids, which are the energy source for gastrointestinal epithelial cells, provide protection against pathogens, influence immunomodulation, and induce apoptosis of colon cancer cells. The oral bioaccessibility and bioavailability of seaweed components is also discussed, including the advantages and limitations of static and dynamic in vitro gastrointestinal models versus ex vivo and in vivo methods. Seaweed bioactives show potential for use in prevention and, in some instances, treatment of human disease. However, it is also necessary to confirm these potential, therapeutic effects in large-scale clinical trials. Where possible, we have cited information concerning these trials.

Potential benefits of dietary seaweeds as protection against COVID-19

The coronavirus disease 2019 (COVID-19) pandemic in Japan is not as disastrous as it is in other Western countries, possibly because of certain lifestyle factors. One such factor might be the seaweed-rich diet commonly consumed in Japan. COVID-19 is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which binds to angiotensin-converting enzyme 2 (ACE2) on the cell surface and downregulates ACE2, likely elevating the ratio of angiotensin-converting enzyme (ACE) to ACE2. The overreaction of the immune system, combined with the cytokine storm and ACE dominance, is purported to cause the condition of COVID-19 patients to deteriorate rapidly. Dietary seaweeds contain numerous components, including ACE inhibitory peptides, soluble dietary fibers (eg, fucoidan, porphyran), omega-3 fatty acids, fucoxanthin, fucosterol, vitamins D3 and B12, and phlorotannins. These components exert antioxidant, anti-inflammatory, and antiviral effects directly as well as indirectly through prebiotic effects. It is possible that ACE inhibitory components could minimize the ACE dominance caused by SARS-CoV-2 infection. Thus, dietary seaweeds might confer protection against COVID-19 through multiple mechanisms. Overconsumption of seaweeds should be avoided, however, as seaweeds contain high levels of iodine.

Enhancement of the Antioxidant and Antimicrobial Activities of Porphyran through Chemical Modification with Tyrosine Derivatives

The chemical modification of porphyran hydrocolloid is attempted, with the objective of enhancing its antioxidant and antimicrobial activities. Sulfated galactan porphyran is obtained from commercial samples of the red algae Porphyra dioica using Soxhlet extraction with water at 100 °C and precipitation with isopropyl alcohol. The extracted porphyran is then treated with modified L-tyrosines in aqueous medium in the presence of NaOH, at ca. 70 °C. The modified tyrosines L1 and L2 are prepared through a Mannich reaction with either thymol or 2,4-di-tert-butylphenol, respectively. While the reaction with 2,4-di-tert-butylphenol yields the expected tyrosine derivative, a mixture of products is obtained with thymol. The resulting polysaccharides are structurally characterized and the respective antioxidant and antimicrobial activities are determined. Porphyran treated with the N-(2-hydroxy-3,5-di-tert-butyl-benzyl)-L-tyrosine derivative, POR-L2, presents a noticeable superior radical scavenging and antioxidant activity compared to native porphyran, POR. Furthermore, it exhibited some antimicrobial activity against S. aureus. The surface morphology of films prepared by casting with native and modified porphyrans is studied by SEM/EDS. Both POR and POR-L2 present potential applicability in the production of films and washable coatings for food packaging with improved protecting characteristics.

Medicinal Prospects of Antioxidants From Algal Sources in Cancer Therapy

Though cancer therapeutics can successfully eradicate cancerous cells, the effectiveness of these medications is mostly restricted to several deleterious side effects. Therefore, to alleviate these side effects, antioxidant supplementation is often warranted, reducing reactive species levels and mitigating persistent oxidative damage. Thus, it can impede the growth of cancer cells while protecting the normal cells simultaneously. Moreover, antioxidant supplementation alone or in combination with chemotherapeutics hinders further tumor development, prevents chemoresistance by improving the response to chemotherapy drugs, and enhances cancer patients' quality of life by alleviating side effects. Preclinical and clinical studies have been revealed the efficacy of using phytochemical and dietary antioxidants from different sources in treating chemo and radiation therapy-induced toxicities and enhancing treatment effectiveness. In this context, algae, both micro and macro, can be considered as alternative natural sources of antioxidants. Algae possess antioxidants from diverse groups, which can be exploited in the pharmaceutical industry. Despite having nutritional benefits, investigation and utilization of algal antioxidants are still in their infancy. This review article summarizes the prospective anticancer effect of twenty-three antioxidants from microalgae and their potential mechanism of action in cancer cells, as well as usage in cancer therapy. In addition, antioxidants from seaweeds, especially from edible species, are outlined, as well.

Purification, structural characterization, and biological activities of degraded polysaccharides from Porphyra yezoensis

The degraded polysaccharides from Porphyra yezoensis (DPPY) prepared using the H₂ O₂ -Vc method under optimized conditions were isolated and purified by DEAE Cellulose-52, and Sephadex G-100, providing four pure components, namely, DPPY-0, DPPY-0.1, DPPY-0.3, and DPPY-0.5. Their relative molecular weights were measured to be 10.8, 10.7, 18.7, and 35.5 kDa, respectively. GC-MS analysis revealed that all the four fractions were mainly composed of galactose, together with a small portion of glucose, mannose, xylose, and rhamnose. Structural analysis revealed that the purified polysaccharides mainly possess a backbone of (1 → 3)-β-D-galactose (1 → 4)-3,6-anhydro-α-L-galactopyranose (G-A) units and (1 → 3)-β-D-galactose (1 → 4)-α-L-galactose-6-sulfate (G-L6S) units. They were found to promote the proliferation of RAW264.7 macrophages and enhance phagocytosis of the RAW264.7 cells. Antioxidant assays indicated that DPPY-0.5 possessed the most potent reducing power and free radical scavenging ability among the four purified polysaccharides. High sulfate content and proper molecular weight of these fractions are favorable to their immunomodulatory and antioxidant activities. PRACTICAL APPLICATIONS: Porphyra yezoensis, common economic red algae widely distributed in East Asian countries, contains a high content of polysaccharides with a variety of biological activities. However, P. yezoensis polysaccharide (PPY) has not been well utilized due to the relatively low biological activities and lack of understanding of its structure-activity relationship. Thus, it is necessary to improve the bioactivities and elucidate the structure-activity relationship of this polysaccharide for its practical use. In the present work, four purified fractions (DPPY-0, DPPY-0.1, DPPY-0.3, and DPPY-0.5) were isolated from the degraded P. yezoensis polysaccharide, and were investigated for their antioxidant and immunoregulatory activities. The results of the present work will lay a foundation for the application of the degraded P. yezoensis polysaccharide in the food industry as a functional food ingredient.

Porphyran and oligo-porphyran originating from red algae Porphyra: Preparation, biological activities, and potential applications

Porphyra is one of the most economically important red algae in the world. The functional components extracted from Porphyra such as porphyrans, proteins, lipids, and minerals have strong physiological activities. Porphyran, a sulfated galactan, is composed of alternating 1,4-linked α-l-galactopyranose-6-sulfate (L6S) and 1,3-linked β-d-galactopyranose (G). Porphyran and oligo-porphyran have a series of pharmacological and biological functions, such as antioxidation, anticancer, antiaging, antiallergic, immunomodulatory, hypoglycaemic, and hypolipidemic effects. Thus, red algae Porphyra-derived porphyran and oligo-porphyran have various potential applications in food, medicine, and cosmetic fields. For better application, this review introduces and summarizes the structure and source of porphyran as well as the preparation methods, biological activities, and potential applications of porphyran and oligo-porphyran. Moreover, the future research directions and emphasis of porphyran and oligo-porphyran preparation as well as their functional activities and applications are highlighted and prospected.