Activation of murine macrophages by polysaccharide fractions from marine algae (Porphyra yezoensis)

Bioactive Carbohydrate Polymers-Between Myth and Reality

Polysaccharides are complex macromolecules long regarded as energetic storage resources or as components of plant and fungal cell walls. They have also been described as plant mucilages or microbial exopolysaccharides. The development of glycosciences has led to a partial and difficult deciphering of their other biological functions in living organisms. The objectives of glycobiochemistry and glycobiology are currently to correlate some structural features of polysaccharides with some biological responses in the producing organisms or in another one. In this context, the literature focusing on bioactive polysaccharides has increased exponentially during the last two decades, being sometimes very optimistic for some new applications of bioactive polysaccharides, notably in the medical field. Therefore, this review aims to examine bioactive polysaccharide, taking a critical look of the different biological activities reported by authors and the reality of the market. It focuses also on the chemical, biochemical, enzymatic, and physical modifications of these biopolymers to optimize their potential as bioactive agents.

Viral inhibitors derived from macroalgae, microalgae, and cyanobacteria: A review of antiviral potential throughout pathogenesis

Viruses are abiotic obligate parasites utilizing complex mechanisms to hijack cellular machinery and reproduce, causing multiple harmful effects in the process. Viruses represent a growing global health concern; at the time of writing, COVID-19 has killed at least two million people around the world and devastated global economies. Lingering concern regarding the virus' prevalence yet hampers return to normalcy. While catastrophic in and of itself, COVID-19 further heralds in a new era of human-disease interaction characterized by the emergence of novel viruses from natural sources with heretofore unseen frequency. Due to deforestation, population growth, and climate change, we are encountering more viruses that can infect larger groups of people with greater ease and increasingly severe outcomes. The devastation of COVID-19 and forecasts of future human/disease interactions call for a creative reconsideration of global response to infectious disease. There is an urgent need for accessible, cost-effective antiviral (AV) drugs that can be mass-produced and widely distributed to large populations. Development of AV drugs should be informed by a thorough understanding of viral structure and function as well as human biology. To maximize efficacy, minimize cost, and reduce development of drug-resistance, these drugs would ideally operate through a varied set of mechanisms at multiple stages throughout the course of infection. Due to their abundance and diversity, natural compounds are ideal for such comprehensive therapeutic interventions. Promising sources of such drugs are found throughout nature; especially remarkable are the algae, a polyphyletic grouping of phototrophs that produce diverse bioactive compounds. While not much literature has been published on the subject, studies have shown that these compounds exert antiviral effects at different stages of viral pathogenesis. In this review, we follow the course of viral infection in the human body and evaluate the AV effects of algae-derived compounds at each stage. Specifically, we examine the AV activities of algae-derived compounds at the entry of viruses into the body, transport through the body via the lymph and blood, infection of target cells, and immune response. We discuss what is known about algae-derived compounds that may interfere with the infection pathways of SARS-CoV-2; and review which algae are promising sources for AV agents or AV precursors that, with further investigation, may yield life-saving drugs due to their diversity of mechanisms and exceptional pharmaceutical potential.

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.

Structure and Bioactivities of Porphyrans and Oligoporphyrans

BACKGROUND

Pyropia (Porphyra), commonly known as nori or laver, is an important food source in many parts of the world. Edible dried Pyropia contains numerous nutrients and biofunctional components, including proteins, vitamins, eicosapentaenoic acid, minerals, carotenoids, mycosporine-like amino acids, and carbohydrate, and one of the compounds which we are interested in is porphyran, a sulfated polysaccharide comprising the hot-water-soluble portion of Pyropia cell walls. Researchers have performed a large number of in-depth studies on the biological activity and potential therapeutic applications of porphyrans and oligoporphyrans.

METHODS

This mini review aims to provide comprehensive and update overview on the source, extraction, structure, biological activities and structure-activity relationships of porphyrans and oligoporphyrans based on the studies in the past 30 years which were included in Web of Science.

RESULTS

The structure of porphyran has been basically determined given that its straight chain is relatively simple, and the skeleton structure has been described. The extraction methods were simplified continuously, but different extraction methods and post- processing methods still had great influence on the structure and composition of porphyran, so there was no standardized extraction process which can achieve quality control until now. In order to obtain oligoporphyrans, there are a variety of degradation methods, including chemical method, physical method and enzymatic method, but it is worth mentioning that specific degradation enzyme is still unavailable. Studies on the biological and pharmacology properties include antioxidant, anti-tumor, anti-inflammatory, immunomodulation, anti-cardiovascular and cerebrovascular diseases and drug delivery.

CONCLUSION

Owing to the therapeutic potential and drug delivery applications, porphyran and oligoporphyrans are expected to be further developed as a medicine against human diseases, as well as a supplement in cosmetics and health products.

Porphyran isolated from Pyropia yezoensis inhibits lipopolysaccharide-induced activation of dendritic cells in mice

We previously demonstrated that porphyran, a sulfated polysaccharide extracted from Pyropia yezoensis, shows protective effects on LPS-induced septic shock in the mouse. However, the immune cell-mediated inhibitory effect of porphyran in LPS-induced activation of immune cells has not been well investigated. In this study, we found that treatment of porphyran suppressed LPS-induced upregulation of costimulatory molecule and C-C chemokine receptor type 7 (CCR7) expression in bone marrow-derived dendritic cells (BMDCs) in vitro and spleen DCs in vivo. Moreover, the LPS-induced expression of IL-6, IL-12, and TNF-α in the culture medium of BMDCs and serum dose-dependently decreased by porphyran treatment, which contributed to the inhibition of the intracellular cytokine production in spleen DCs. In addition, LPS-induced differentiation of helper T1 (Th1) and cytotoxic T1 (Tc1) cells was effectively suppressed by porphyran treatment in mice. The inhibitory effect of porphyran in LPS-induced immune activation was mediated by competitive binding of porphyran with LPS in spleen DCs. Thus, these results suggest that porphyran is a promising potential therapeutic agent in endotoxin-mediated inflammatory disease and septic shock.

Immunomodulatory and Antioxidant Activities of Sulfated Polysaccharides from Laminaria ochroleuca, Porphyra umbilicalis, and Gelidium corneum

Seaweeds of the genera Laminaria, Gelidium, and Porphyra have been used in both food and non-food industries due to their unique properties and characteristic biological activity. This study assesses the antioxidant activity and immunomodulatory properties of the acidic polysaccharides extracted from Laminaria ochroleuca, Porphyra umbilicalis, and Gelidium corneum collected in the Atlantic coast of Tarifa (Cadiz, Spain). The proliferation of murine cell line RAW 264 decreased with increasing concentration of polysaccharides of the three algal species. The highest both antioxidant (25.69 μmol TE g-1 DW) and immunomodulatory activities were observed in the sulfated polysaccharides of L. ochroleuca compared to that of P. umbilicalis and G. corneum. Sulfated polysaccharides of L. ochroleuca presented high potential anticancer activity in cell lines of human colon cancer HTC-116 (IC50 = 0.44 mg mL-1), human malignant melanoma G-361 (IC50 = 5.42 mg mL-1), breast adenocarcinoma human MCF-7 (IC50 = 8.32 mg mL-1), and human leukemia U-937 (IC50 = 3.72 mg mL-1). It is concluded that metabolites of L. ochroleuca can offer significant advantages for the pharmaceutical industry, particularly when macrophage activation is required.

Quantitative Analysis of Polysaccharide Composition in Polyporus umbellatus by HPLC-ESI-TOF-MS

Polyporus umbellatus is a well-known and important medicinal fungus in Asia. Its polysaccharides possess interesting bioactivities such as antitumor, antioxidant, hepatoprotective and immunomodulatory effects. A qualitative and quantitative method has been established for the analysis of 12 monosaccharides comprising polysaccharides of Polyporus umbellatus based on high-performance liquid chromatography coupled with electrospray ionization–ion trap–time of flight–mass spectrometry. The hydrolysis conditions of the polysaccharides were optimized by orthogonal design. The results of optimized hydrolysis were as follows: neutral sugars and uronic acids 4 mol/L trifluoroacetic acid (TFA), 6 h, 120 °C; and amino sugars 3 mol/L TFA, 3 h, 100 °C. The resulting monosaccharides derivatized with 1-phenyl-3-methyl-5-pyrazolone have been well separated and analyzed by the established method. Identification of the monosaccharides was carried out by analyzing the mass spectral behaviors and chromatography characteristics of 1-phenyl-3-methyl-5-pyrazolone labeled monosaccharides. The results showed that polysaccharides in Polyporus umbellatus were composed of mannose, glucosamine, rhamnose, ribose, lyxose, erythrose, glucuronic acid, galacturonic acid, glucose, galactose, xylose, and fucose. Quantitative recoveries of these monosaccharides in the samples were in the range of 96.10–103.70%. This method is simple, accurate, and sensitive for the identification and quantification of monosaccharides, and can be applied to the quality control of Polyporusumbellatus as a natural medicine.

Immunostimulatory effect of pepsin enzymatic extract from Porphyra yezoensis on murine splenocytes

BACKGROUND

Porphyra yezoensis is a red alga consumed mainly in Korea, Japan, and China for food. This study researches the immunological effect of pepsin extract of P. yezoensis (PPEE) on murine splenocytes.

RESULTS

PPEE was not toxic on murine splenocytes and dramatically increased the proliferation of splenocytes compared with untreated control. Flow cytometry assay performed to sum up the effect of PPEE (31.3 and 62.5 µg mL^-1 ) on major immune cells revealed that PPEE had no effect on the function of CD3e⁺ CD4⁺ T-helper cells, CD3e⁺ CD8⁺ T-cytotoxic cells, or CD44⁺ CD62L^- effector T cells in splenocytes compared with untreated control. More importantly, CD45⁺ CD11b⁺ macrophage and dendritic cell populations and Ly-6C⁺ Ly-6G⁺ macrophages/monocytes in splenocytes were activated by PPEE treatment compared with untreated control. Further experiments showed that PPEE treatment increased the secretion of macrophage-derived cytokines such as interleukin-1β, tumor necrosis factor-α, and interleukin-12, and macrophage-activating cytokines interferon-γ and interleukin-10 compared with untreated control.

CONCLUSION

Taken together, these results suggest that PPEE has an immune stimulatory effect on macrophages, dendritic cells, and memory T cells. This property signifies the potential medicinal value of PPEE in clinical implications for immune-compromised diseases. © 2017 Society of Chemical Industry.

Global restriction of using antibiotic growth promoters and alternative strategies in poultry production

A growing global concern of antibiotic use in poultry diets due to its potential adverse effects on birds and human health, food safety and the environment has led to a complete ban or restricted use in some countries, and, at the same time, expanding options for the use of alternative feed additives. Multiple, rather than a single additive may replace antibiotic growth promoters (AGPs) in poultry. Blending of feeding additives and hygienic farm management, vaccination and biosecurity may help achieve good intestinal health, stabilise enteric ecosystems and result in sustainable and cost effective production performance of birds. Moreover, controlling unsolicited ingredients at the production level must have the support of different markets responsible for the supply of safe and quality poultry products for consumers. This requires the further increase and diversification of value added poultry products and the expansion of their markets through strategic planning and gradual limitation of live bird markets. More research is warranted in order to explore suitable, reliable and cost effective alternatives to AGPs for commercial use, and strategic poultry value chain development.

Isolation and Characterization of a Glycosyl Hydrolase Family 16 β-Agarase from a Mangrove Soil Metagenomic Library

A mangrove soil metagenomic library was constructed and a β-agarase gene designated as AgaML was isolated by functional screening. The gene encoded for a 659-amino-acids polypeptide with an estimated molecular mass of 71.6 kDa. The deduced polypeptide sequences of AgaML showed the highest identity of 73% with the glycoside hydrolase family 16 β-agarase from Microbulbifer agarilyticus in the GenBank database. AgaML was cloned and highly expressed in Escherichia coli BL21(DE3). The purified recombinant protein, AgaML, showed optimal activity at 50 °C and pH 7.0. The kinetic parameters of Km and Vmax values toward agarose were 4.6 mg·mL(-1) and 967.5 μM·min(-1)·mg(-1), respectively. AgaML hydrolyzed the β-1,4-glycosidic linkages of agar to generate neoagarotetraose (NA4) and neoagarohexaose (NA6) as the main products. These characteristics suggest that AgaML has potential application in cosmetic, pharmaceuticals and food industries.

Marine polysaccharides from algae with potential biomedical applications

There is a current tendency towards bioactive natural products with applications in various industries, such as pharmaceutical, biomedical, cosmetics and food. This has put some emphasis in research on marine organisms, including macroalgae and microalgae, among others. Polysaccharides with marine origin constitute one type of these biochemical compounds that have already proved to have several important properties, such as anticoagulant and/or antithrombotic, immunomodulatory ability, antitumor and cancer preventive, antilipidaemic and hypoglycaemic, antibiotics and anti-inflammatory and antioxidant, making them promising bioactive products and biomaterials with a wide range of applications. Their properties are mainly due to their structure and physicochemical characteristics, which depend on the organism they are produced by. In the biomedical field, the polysaccharides from algae can be used in controlled drug delivery, wound management, and regenerative medicine. This review will focus on the biomedical applications of marine polysaccharides from algae.

The beneficial properties of marine polysaccharides in alleviation of allergic responses

Marine polysaccharides have been found as the principle component in cell wall structures of seaweeds or exoskeletons of crustaceans. Due to numerous pharmaceutical properties of marine polysaccharides such as antioxidant, anti-inflammatory, antiallergic, antitumor, antiobesity, antidiabetes, anticoagulant, antiviral, immunomodulatory, cardioprotective, and antihepatopathy activities, they have been applied in many fields of biomaterials, food, cosmetic, and pharmacology. Recently, several marine polysaccharides such alginate, porphyran, fucoidan, and chitin and its derivatives have been evidenced as downregulators of allergic responses due to enhancement of innate immune system, alteration of Th1/Th2 balance forward to Th1 cells, inhibition of IgE production, and suppression of mast cell degranulation. This contribution, therefore, focuses on antiallergic properties of marine polysaccharides and emphasizes their potential application as bioactive food ingredients as well as nutraceuticals for prevention of allergic disorders.

Analysis of the monosaccharide composition of water-soluble polysaccharides from Sargassum fusiforme by high performance liquid chromatography/electrospray ionisation mass spectrometry

Sargassum fusiforme (hijiki) is the well-known edible algae, whose polysaccharides have been proved to possess interesting bioactivities like antitumor, antioxidant, antimicrobial and immunomodulatory activities. A facile and sensitive method based on high-performance liquid chromatography method of pre-column derivatization with 1-phenyl-3-methyl-5-pyrazolone (PMP) coupled with electrospray ionisation mass spectrometry (HPLC/ESI-MS) has been established for the analysis of the monosaccharide composition of polysaccharides in S. fusiforme. Monosaccharides have been converted into PMP-labelled derivatives with aqueous ammonia as a catalyst at 70 °C for 30 min. The optimisation of the pre-column derivatization process was studied. The LODs of the monosaccharides were in the range from 0.01 to 0.02 nmol. PMP-labelled mixture of monosaccharides has been well separated by a reverse-phase HPLC and detected by on-line ESI-MS method under optimised conditions. The mobile phase of elution system was chosen as acetonitrile (solvent A) and 20mM aqueous ammonium acetate (solvent B) (pH 3.0) with Zorbax XDB-C18 column at 30 °C for the separation of the monosaccharide derivatives. Identification of the monosaccharides composition was carried out by analysis with mass spectral behaviour and chromatography characteristics of 1-phenyl-3-methyl-5-pyrazolone (PMP) labelled monosaccharides. All PMP-labelled derivatives display high chemical stabilities, whose regular MS fragmentation is specific for reducing labelled sugars. The result showed that the S. fusiforme polysaccharide consisted of mannose, glucose, galactose, xylose, fucose and glucuronic acid or galacturonic acid, or both uronic acids.

Marine-derived polysaccharides for regulation of allergic responses

Polysaccharides are macromolecules made up of many monosaccharides joined together by glycosidic bonds. Polysaccharides from marine sources are widely distributed as the principle component in cell wall structures of seaweeds or exoskeletons of crustaceans. So far, marine polysaccharides have been used in many fields of biomaterials, food, cosmetic, and pharmacology. Especially, numerous pharmaceutical properties of marine polysaccharides have been revealed such as antioxidant, anti-inflammatory, antiallergic, antitumor, antiobesity, antidiabetes, anticoagulant, antiviral, immunomodulatory, cardioprotective, antihepatopathy, antiuropathy, and antirenalpathy activities. Recently, several marine polysaccharides such alginate, porphyran, fucoidan, and chitin and its derivatives have been found as modulators of allergic responses due to enhancing innate immune system, altering Th1/Th2 balance, inhibiting IgE production, and suppressing mast cell degranulation. This contribution, therefore, focuses specially on the immunomodulatory effect of marine polysaccharides and emphasizes their potential application as candidates of pharmaceuticals as well as nutraceuticals to prevent allergic disorders.

Enhancement of intestinal IgA production by Ajoene in mice

We investigated the effects of ajoene on intestinal IgA production. Ajoene (1.35, 4.5, and 13.5 µg/kg/d) was administered to mice for 4 weeks. The fecal IgA level in the 13.5 µg/kg/d group increased after 3 weeks. The intestinal IgA level also increased in a dose-dependent manner upon ajoene administration. An oil-macerated garlic extract, with 1500 µg/g of ajoene, enhanced the intestinal IgA production.

Effect of dietary porphyran from the red alga, Porphyra yezoensis, on glucose metabolism in diabetic KK-Ay mice

Porphyran (POR) from the red alga Porphyra yezoensis is a water soluble dietary fiber. In this study, we investigated the effect of dietary POR on glucose metabolism in KK-Ay mice (a model for type 2 diabetes). Mice were divided into 4 groups and fed a diet containing 5% cellulose (control), POR, POR Arg or POR K. After 3 wk of feeding, plasma insulin levels and the calculated homeostasis model assessment-insulin resistance (HOMA-IR) index were significantly lower in the POR group than in the control group. Compared with the control group, plasma adiponectin levels were significantly increased in the POR, POR Arg and POR K groups. These results suggest that dietary POR should improve glucose metabolism in diabetes via up-regulation of adiponectin levels. In addition, the amount of propionic acid in the cecum of the POR group was significantly higher than in the control group and the profile of bacterial flora was changed by dietary POR. In the cecum of the POR, POR Arg and POR K groups, Bacteroides was significantly increased and Clostridium coccoides was significantly decreased compared with in the control group. The effects of dietary POR on the hindgut environment might contribute to the improvement of glucose metabolism.

Natural alternatives to in-feed antibiotics in pig production: can immunomodulators play a role?

As a result of the European ban of in-feed growth-promoting antibiotics, new strategies are being developed to increase the resistance to disease in farm animals. In pig production, this is of particular importance during the weaning transition when piglets are subjected to major stressful events, making them highly sensitive to digestive disorders. At this time, the development of both innate and adaptive immunity at the mucosal surface is critical in preventing the potential harmful effects of intestinal pathogenic agents. Strategies aiming at stimulating natural host defences through the use of substances able to modulate immune functions have gained increasing interest in animal research, and different bioactive components a priori sharing those properties have been the subject of in vivo nutritional investigations in pig. Among these, yeast derivates (β-glucans and mannans) are able to interact with immune cells, particularly phagocytic cells. However, studies where they have been fed to pigs have shown inconsistent results, suggesting that their ability to target the sensitive immune cells through the oral route is questionable. The plant extracts, which would benefit from a positive image in the public opinion, have also been tested. However, due to a lack of data on the bioactive components of particular plants and the large diversity of species, it has proved difficult to prepare extracts of equivalent potency and thus, the literature on their influence on pig immunity remains inconclusive. In considering piglet immunity and health benefits, the most promising results to date have been obtained with spray-dried animal plasma, whose positive effects would be provided by specific antibodies and non-specific competition of some plasma components with bacteria for intestinal receptors. The major positive effect of spray-dried animal plasma is in reducing the infiltration of gut-associated lymphoid tissue by immune cells, which is likely to be the result of a decreased colonisation by potentially harmful bacteria. This review also highlights the limitations of some of the published in vivo studies on the immunomodulatory activity of certain feed additives. Among those, the lack of standardisation of extracts and the heterogeneity of piglet-rearing conditions (e.g. exposure to pathogens) are likely the most limiting.

Application of power plant flue gas in a photobioreactor to grow Spirulina algae, and a bioactivity analysis of the algal water-soluble polysaccharides

A novel photobioreactor was developed with a total volume of 30 m(3) which required merely 100 m(3) of land footprint. The bioreactor was capable of utilizing CO(2) in the flue gas of a power plant as the carbon source for the growth of a freshwater alga, Spirulina platensis, mitigating the greenhouse effect caused by the same amount of CO(2) discharge. Results of the study indicated that the photobioreactor was capable of fixing 2,234 kg of CO(2) per annum. Upon deducting the energy consumption of operating the bioreactor unit, the estimated amount of CO(2) to be fixed by a scaled-up reactor would be 74 tons ha(-1)year(-1). In addition, the study prove that protein-free polysaccharides of S. platensis could induce the production of pro-IL-1 and IL-1 proteins through the mediation of ERK, JNK, and p38 MAPKs pathways. As a consequence, immunogenic activities of the macrophage cells were enhanced.

Physicochemical properties and inhibition effect on iron deficiency anemia of a novel polysaccharide-iron complex (LPPC)

Porphyran (P) was extracted from red algae Porphyra by boiling water. A novel polysaccharide-iron complex (LPPC) was prepared under the alkaline condition by adding a ferric chloride solution to the low molecular weight porphyran (LP) solution. Physicochemical properties and inhibition effect on iron deficiency anemia of this complex were studied. The content of iron(III) in the complex is 21.57% determined with iodometry. The results indicate that LPPC was product required. The complex can increase red blood cell count (RBC), hemoglobin (Hb), Serum iron (SI), spleen index, spleen mass and mass of mice with iron deficiency anemia (IDA). Although the structure and deeper mechanisms on hemolytic anemia of LPPC should be further studied, LPPC is hoped to be developed as a late-model iron supplement which has a synergism on anemia.

Medicinal benefits of sulfated polysaccharides from sea vegetables

The cell walls of sea vegetables or marine algae are rich in sulfated polysaccharides (SPs) such as fucoidans in brown algae, carrageenans in red algae, and ulvans in green algae. These SPs exhibit various biological activities such as anticoagulant, antiviral, antioxidative, and anticancer activities with potential health benefits. Therefore, SPs derived from sea vegetables have great potential in further development as nutraceuticals and medicinal foods. This chapter presents an overview of biological activities and potential medicinal benefits of SPs derived from sea vegetables.

Marine polysaccharides in pharmaceutical applications: an overview

The enormous variety of polysaccharides that can be extracted from marine plants and animal organisms or produced by marine bacteria means that the field of marine polysaccharides is constantly evolving. Recent advances in biological techniques allow high levels of polysaccharides of interest to be produced in vitro. Biotechnology is a powerful tool to obtain polysaccharides from a variety of micro-organisms, by controlling the growth conditions in a bioreactor while tailoring the production of biologically active compounds. Following an overview of the current knowledge on marine polysaccharides, with special attention to potential pharmaceutical applications and to more recent progress on the discovering of new polysaccharides with biological appealing characteristics, this review will focus on possible strategies for chemical or physical modification aimed to tailor the final properties of interest.

Preparation of the different derivatives of the low-molecular-weight porphyran from Porphyra haitanensis and their antioxidant activities in vitro

Porphyran extracted from Porphyra haitanensis is a sulfated polysaccharide, which possesses excellent antioxidant activities. In this study, we prepared one low-molecular-weight porphyran and its sulfated, acetylated, phosphorylated and benzoylated derivatives. Their antioxidant activities were investigated including scavenging effect of superoxide, hydroxyl and 1,1-diphenyl-2-picrylhydrazyl radicals. The results of chemical analysis and FT-IR spectrums showed the modification was successful. And in addition, we found that certain derivative exhibited stronger antioxidant activity than low-molecular-weight porphyran. The benzoylated derivative showed the most excellent antioxidant activity in three assays, so this derivative needs to be attended to.

Effect of Ultrasonic Degradation on In Vitro Antioxidant Activity of Polysaccharides from Porphyra yezoensis (Rhodophyta)

This article aims to study the effect of ultrasonic degradation on antioxidant activity of polysaccharides from Porphyra yezoensis (Rhodophyta) (PSPY), and to look for the relationship between molecular structure of fractions (F1, F2, and F3) from ultrasonic-degraded PSPY (UDPSPY) and their activities of scavenging hydroxyl and superoxide anion radicals, chelating ability of iron ion and reducing power. Results of antioxidant assays indicated that the UDPSPY had higher antioxidant activity of scavenging superoxide anion radical and hydroxyl radical than that of the PSPY. As antioxidant activities of the fractions are concerned, this result might suggest that decreasing molecular weight and increasing sulfate group content in the molecule were vital and necessary factors for improving antioxidant activity of PSPY. Decrease of molecular weight was the dominant reason for increasing activities of scavenging non-site and site specific hydroxyl radical and reducing power of F1, F2, and F3, and increase of sulfate group content in the molecule was the dominant reason for increasing activities of scavenging superoxide anion radical and chelating ferrous ions of F1, F2, and F3. It was possible that ultrasonic treatment could be a new and effective method for enhancing PSPY's antioxidant activity.

Immunomodulating activities of acidic sulphated polysaccharides obtained from the seaweed Ulva rigida C. Agardh

Water-soluble acidic polysaccharides from the cell walls of Ulva rigida are mainly composed of disaccharides that contain glucuronic acid and sulphated rhamnose. The structure of disaccharides resembles that of glycosaminoglycans (GAGs) as they both contain glucuronic acid and sulphated sugars. Glycosaminoglycans occur in the extracellular matrix of animal connective tissues but can also be produced by leucocytes at inflammatory sites. Certain types of GAGs can even activate macrophages and therefore the acidic polysaccharides from U. rigida probably modulate macrophage activity. In the present study, we evaluated the effects of U. rigida polysaccharides on several RAW264.7 murine macrophage activities, including expression of inflammatory cytokines and receptors, nitric oxide and prostaglandin E2 (PGE(2)) production, and nitric oxide synthase 2 (NOS-2) and cyclooxygenase-2 (COX-2) gene expression. U. rigida acidic polysaccharides induced a more than two-fold increase in the expression of several chemokines (chemokine (C motif) ligand 1, chemokine (C-X-C motif) ligand 12, chemokine (C-C motif) ligand 22 and chemokine (C-X-C motif) ligand 14 (Cxcl14)) and in the expression of IL6 signal transducer and IL12 receptor beta 1. Incubation of macrophages with U. rigida polysaccharides also induced an increase in nitrite production, although this effect decreased considerably after desulphation of polysaccharides, suggesting that the sulphate group is important for the stimulatory capacity of these molecules. U. rigida polysaccharides also stimulated macrophage secretion of PGE(2) and induced an increase in COX-2 and NOS-2 expression. The results indicate that U. rigida acid polysaccharide can be used as an experimental immunostimulant for analysing inflammatory responses related to macrophage functions. In addition, these polysaccharides may also be of clinical interest for modifying certain macrophage activities in diseases where macrophage function is impaired or needs to be boosted.

Porphyran induces apoptosis related signal pathway in AGS gastric cancer cell lines

Porphyrans, the sulfated polysaccharides, are the main components of Porphyra. The potential apoptotic activities of porphyran were evaluated using AGS human gastric cancer cells. Porphyran did not affect the growth of normal cells, but did induce cancer cell death in a dose-dependent manner. The addition of 0.1% porphyran also reduced DNA synthesis after 24 h of exposure, suggesting that porphyran inhibits cancer cell growth by both decreasing cell proliferation and inducing apoptosis. AGS cells treated with porphyran displayed a marked increase in poly(ADP-ribose) polymerase (PARP) cleavage, as well as caspase-3 activation. The ability of porphyran to promote apoptosis may contribute to its usefulness as an agent capable of significantly inhibiting cell growth in AGS human gastric cancer cells. Insulin-like growth factor-I receptor (IGF-IR) phosphorylation was decreased in porphyran-treated AGS cells compared to control cells, which correlated with Akt activation. Thus, porphyran appears to negatively regulate IGF-IR phosphorylation by causing a decrease in the expression levels in AGS gastric cancer cells, and then inducing caspase-3 activation.

Degradation of porphyran from Porphyra haitanensis and the antioxidant activities of the degraded porphyrans with different molecular weight

In the present paper, ascorbate and hydrogen peroxide (H2O2) were used to degrade porphyran. It was found that porphyran could be degraded by free radical that was generated by ascorbate and H2O2 in combination. It was possible to prepare desired porphyran products with different molecular weight by adjusting ascorbate to H2O2 proportions and their concentrations. The molar ratio of 1 was demonstrated more effective than in other ratios. Higher concentrations accelerated the degradation. Moreover, results of chemical analysis and FT-IR spectra suggested that the main structure of degraded products still remained although some changes happened. The degraded and natural porphyrans possessed scavenging 1,1-diphenyl-2-picrylhydrazyl (DPPH)-radical activity and reducing power. Higher antioxidant activities were found in both systems when the molecular weight was reduced. The results indicated that the antioxidant activities were closely related to the molecular weight. The degraded porphyrans are potential antioxidant in vitro.

Characterization of a novel β-agarase from marine Alteromonas sp. SY37–12 and its degrading products

The phenotypic and agarolytic features of an unidentified marine bacteria isolated from the southern ocean of China was studied. The strain was gram-negative, aerobic, and polarly flagellated. It was identified as the genus Alteromonas according to its morphological and physiological characterization. In solid agar, the isolate produced a diffusible agarase that caused agar softening around the colonies. An extracellular agarase was purified by the procedure of ammonium sulfate precipitation, gel filtration on Sephacryl S-100HR, and ion-exchange chromatography on diethylaminoethyl-Sepharose. The purified protein exhibited a single band on SDS-PAGE with a molecular mass of 39.5 kDa. The enzyme hydrolyzed the beta-1,4-glycosidic linkages of agar, yielding neoagarotetraose and neoagarohexaose as the main products. The optimum reaction temperature of the agarase was 35 degrees C, with a narrow range from 30 to 45 degrees C. The enzyme activity reached the maximum at pH 7.0 and in the presence of 2% NaCl. Molecular mass and degrading products showed that the agarase from Alteromonas sp. SY 37-12 was much different from those previously reported.

Botanical polysaccharides: macrophage immunomodulation and therapeutic potential

Botanical polysaccharides exhibit a number of beneficial therapeutic properties, and it is thought that the mechanisms involved in these effects are due to the modulation of innate immunity and, more specifically, macrophage function. In this review, we summarize our current state of understanding of the macrophage modulatory effects of botanical polysaccharides isolated from a wide array of different species of flora, including higher plants, mushrooms, lichens and algae. Overall, the primary effect of botanical polysaccharides is to enhance and/or activate macrophage immune responses, leading to immunomodulation, anti-tumor activity, wound-healing and other therapeutic effects. Furthermore, botanical and microbial polysaccharides bind to common surface receptors and induce similar immunomodulatory responses in macrophages, suggesting that evolutionarily conserved polysaccharide structural features are shared between these organisms. Thus, the evaluation of botanical polysaccharides provides a unique opportunity for the discovery of novel therapeutic agents and adjuvants that exhibit beneficial immunomodulatory properties.

Preparation and in vitro antioxidant activity of kappa-carrageenan oligosaccharides and their oversulfated, acetylated, and phosphorylated derivatives

In order to study the relationship between chemical structure and properties of modified carrageenans versus antioxidant activity in vitro, kappa-carrageenan oligosaccharides were prepared through mild hydrochloric acid hydrolysis of the polysaccharide, and these were used as starting materials for the partial synthesis of their oversulfated, acetylated, and phosphorylated derivatives. The structure and substitution pattern of the oligosaccharides and their derivatives were studied using FTIR and (13)C NMR spectroscopy, and their in vitro antioxidant activities were investigated. Certain derivatives of the carrageenan oligosaccharides exhibited higher antioxidant activity than the polysaccharides and oligosaccharides in certain antioxidant systems. The oversulfated and acetylated derivatives, which scavenge superoxide radicals, the phosphorylated and low-DS acetylated derivatives, which scavenge hydroxyl radicals, and the phosphorylated derivatives, which scavenge DPPH radicals, all exhibited significant antioxidant activities in the systems examined. The effect of the molecular weight of the carrageenan on antioxidant activities, however, is not obvious from these studies.