Structural feature and antioxidant activity of low molecular weight laminarin degraded by gamma irradiation

Sulfated Laminarin Polysaccharides Reduce the Adhesion of Nano-COM Crystals to Renal Epithelial Cells by Inhibiting Oxidative and Endoplasmic Reticulum Stress

Purpose: Adhesion between calcium oxalate crystals and renal tubular epithelial cells is a vital cause of renal stone formation; however, the drugs that inhibit crystal adhesion and the mechanism of inhibition have yet to be explored. Methods: The cell injury model was constructed using nano-COM crystals, and changes in oxidative stress levels, endoplasmic reticulum (ER) stress levels, downstream p38 MAPK protein expression, apoptosis, adhesion protein osteopontin expression, and cell-crystal adhesion were examined in the presence of Laminarin polysaccharide (DLP) and sulfated DLP (SDLP) under protected and unprotected conditions. Results: Both DLP and SDLP inhibited nano-COM damage to human kidney proximal tubular epithelial cell (HK-2), increased cell viability, decreased ROS levels, reduced the opening of mitochondrial membrane permeability transition pore, markedly reduced ER Ca2+ ion concentration and adhesion molecule OPN expression, down-regulated the expression of ER stress signature proteins including CHOP, Caspase 12, and p38 MAPK, and decreased the apoptosis rate of cells. SDLP has a better protective effect on cells than DLP. Conclusions: SDLP protects HK-2 cells from nano-COM crystal-induced apoptosis by reducing oxidative and ER stress levels and their downstream factors, thereby reducing crystal-cell adhesion interactions and the risks of kidney stone formation.

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.

Enhancing the potential of rapeseed cake as protein-source food by γ-irradiation

Rapeseed cake serves as a by-product in the oil extraction industry, characterized by its elevated protein content. However, the presence of antinutritional factors limits the utilization of rapeseed cake as a viable protein source. In this study, different doses of γ-irradiation were used to irradiate rapeseed cake and rapeseed protein isolate was extracted through a modified alkaline solution and acid precipitation method from rapeseed cake. The chemical composition and in vivo acute toxicity of rapeseed protein isolate were determined. The protein recovery rate of rapeseed protein isolate was 39.08 ± 3.01% after irradiation, while the content of antinutritional factors was significantly reduced. Moreover, γ-irradiation did not have any experimentally related effects on clinical observations or clinicopathology in mice. Overall, the reduced antinutrients and increased functional properties suggest that the irradiation of rapeseed cake (<9 kGy) could be utilized as a pre-treatment in the development of rapeseed cake-based value-added protein products.

Effects of Oat β-Glucan and Inulin on Alleviation of Nonalcoholic Steatohepatitis Aggravated by Circadian Disruption in C57BL/6J Mice

This was the first study that examined the effects of oat β-glucan and inulin on diet-induced nonalcoholic steatohepatitis (NASH) in circadian-disrupted (CD)-male C57BL/6J mice. CD intensified NASH, significantly increasing alanine aminotransferase and upregulating hepatic tumor necrosis factor α (TNFα) and transforming growth factor β 1 (TGFβ1). However, these observations were significantly alleviated by oat β-glucan and inulin treatments. Compared to CD NASH mice, oat β-glucan significantly decreased the liver index, aspartate aminotransferase (AST), and insulin. In prebiotic-treated and CD NASH mice, significant negative correlations were found between enrichment of Muribaculaceae bacterium Isolate-036 (Harlan), Muribaculaceae bacterium Isolate-001 (NCI), and Bacteroides ovatus after oat β-glucan supplementation with TNFα and TGFβ1 levels; and enrichment of Muribaculaceae bacterium Isolate-110 (HZI) after inulin supplementation with AST level. In conclusion, oat β-glucan and inulin exhibited similar antiliver injury, anti-inflammatory, and antifibrotic activities but had no effect on cecal short-chain fatty acids and gut microbiota diversity in CD NASH mice.

Marine-Originated Materials and Their Potential Use in Biomedicine

Aquatic habitats cover almost 70% of the Earth, containing several species contributing to marine biodiversity. Marine and aquatic organisms are rich in chemical compounds that can be widely used in biomedicine (dentistry, pharmacy, cosmetology, etc.) as alternative raw biomaterials or in food supplements. Their structural characteristics make them promising candidates for tissue engineering approaches in regenerative medicine. Thus, seaweeds, marine sponges, arthropods, cnidaria, mollusks, and the biomaterials provided by them, such as alginate, vitamins, laminarin, collagen, chitin, chitosan, gelatin, hydroxyapatite, biosilica, etc., are going to be discussed focusing on the biomedical applications of these marine-originated biomaterials. The ultimate goal is to highlight the sustainability of the use of these biomaterials instead of conventional ones, mainly due to the antimicrobial, anti-inflammatory, anti-aging and anticancer effect.

Effects of degradation on the physicochemical and antioxidant properties of carboxymethyl pachymaran

Poria cocos (Schw.) Wolf is a well-known edible and medicinal fungus. The polysaccharide in the sclerotium of P. cocos was extracted and prepared into carboxymethyl pachymaran (CMP). Three different degradation treatments including high temperature (HT), high pressure (HP) and gamma irradiation (GI) were used to process CMP. The changes in physicochemical properties and antioxidant activities of CMP were then comparatively investigated. We found that the molecular weights of HT-CMP, HP-CMP, and GI-CMP decreased from 787.9 kDa to 429.8, 569.5 and 6.0 kDa, respectively. Degradation treatments had no effect on the main chains of →3-β-D-Glcp-(1 → while changed the branched sugar residues. The polysaccharide chains of CMP were depolymerized after high pressure and gamma irradiation treatments. The three degradation methods improved the stability of CMP solution while decreased the thermal stability of CMP. In addition, we found that the GI-CMP with lowest molecular weight had the best antioxidant activity. Our results suggest that gamma irradiation treatment could degrade CMP as functional foods with strong antioxidant activity.

Enhancing effects of 60Co irradiation on the extraction and activities of phenolic components in edible Citri Sarcodactylis Fructus

In this study, the impact of ⁶⁰Co-γ ray irradiation treatment on the content of active chemicals and their functions in Citri Sarcodactylis Fructus (CSF) was assessed. Scanning electron microscopy, Fourier transform infrared spectroscopy, and γ-ray diffraction revealed physical structure changes in CSF powder. According to the findings, the content of total flavonoids in the ethanol extract of CSF increased by 9.5%-21.62%, 7-hydroxycoumarin, hesperidin, 5,7-dimethoxycoumarin, and 5-methoxypsoralen increased by 5.31%-51.8%, 10.07%-99.81%, 6.6%-62.29%, and 3.03%-300%, respectively, when the irradiation dosage was raised, and the antibacterial, anti-inflammatory, antioxidant, and anticancer properties were all raised considerably. These results imply that the principal components and activity changes are proportional to the irradiation dosage. At present, the findings of this study serve as a reference for the use of irradiation technology in assisting extraction and enhancing the effects of functional foods.

Mechanisms of action of non-enzymatic antioxidants to control oxidative stress during in vitro follicle growth, oocyte maturation, and embryo development

In vitro follicle growth and oocyte maturation still has a series of limitations, since not all oocytes matured in vitro have the potential to develop in viable embryos. One of the factors associated with low oocyte quality is the generation of reactive oxygen species (ROS) during in vitro culture. Therefore, this review aims to discuss the role of non-enzymatic antioxidants in the control of oxidative stress during in vitro follicular growth, oocyte maturation and embryonic development. A wide variety of non-enzymatic antioxidants (melatonin, resveratrol, L-ascorbic acid, L-carnitine, N-acetyl-cysteine, cysteamine, quercetin, nobiletin, lycopene, acteoside, mogroside V, phycocyanin and laminarin) have been used to supplement culture media. Some of them, like N-acetyl-cysteine, cysteamine, nobiletin and quercetin act by increasing the levels of glutathione (GSH), while melatonin and resveratrol increase the expression of antioxidant enzymes and minimize oocyte oxidative stress. L-ascorbic acid reduces free radicals and reactive oxygen species. Lycopene positively regulates the expression of many antioxidant genes. Additionally, L-carnitine protects DNA against ROS-induced damage, while acteoside and laminarin reduces the expression of proapoptotic genes. Mogrosides increases mitochondrial function and reduces intracellular ROS levels, phycocyanin reduces lipid peroxidation, and lycopene neutralizes the adverse effects of ROS. Thus, it is very important to know their mechanisms of actions, because the combination of two or more antioxidants with different activities has great potential to improve in vitro culture systems.

Biological Properties and Health-Promoting Functions of Laminarin: A Comprehensive Review of Preclinical and Clinical Studies

Marine algal species comprise of a large portion of polysaccharides which have shown multifunctional properties and health benefits for treating and preventing human diseases. Laminarin, or β-glucan, a storage polysaccharide from brown algae, has been reported to have potential pharmacological properties such as antioxidant, anti-tumor, anti-coagulant, anticancer, immunomodulatory, anti-obesity, anti-diabetic, anti-inflammatory, wound healing, and neuroprotective potential. It has been widely investigated as a functional material in biomedical applications as it is biodegradable, biocompatible, and is low toxic substances. The reported preclinical and clinical studies demonstrate the potential of laminarin as natural alternative agents in biomedical and industrial applications such as nutraceuticals, pharmaceuticals, functional food, drug development/delivery, and cosmeceuticals. This review summarizes the biological activities of laminarin, including mechanisms of action, impacts on human health, and reported health benefits. Additionally, this review also provides an overview of recent advances and identifies gaps and opportunities for further research in this field. It further emphasizes the molecular characteristics and biological activities of laminarin in both preclinical and clinical settings for the prevention of the diseases and as potential therapeutic interventions.

An α type gluco-oligosaccharide from brown algae Laminaria japonica stimulated the growth of lactic acid bacteria encoding specific ABC transport system components

Glucan is the most widely distributed glycan. Many probiotics such as lactic acid bacteria (LAB) encoded corresponding hydrolytic enzymes, which could use these glucans as energy substances. Brown alga is rich in glucan and has high edible and medicinal value, but research on its regulation to probiotics is not detailed enough. In this study, we determined a novel neutral α type gluco-oligosaccharide from the brown alga Laminaria japonica with a degree of polymerization (DP) of 2-8 and a structure that mainly consists of α-(1→4)-linked glycosidic bonds called Laminaria japonica gluco-oligosaccharide (LJGO). Fermentation in vitro and gene-phenotype correlation analyses revealed that LJGO selectively stimulated the growth of the LAB strain encoding a specific ATP-binding cassette (ABC) transport system in a GH13 gene cluster, with apparent differences among 14 tested species. Comparative genomics further revealed that this transport system is species-specific, implying a potential contribution to species evolution. Transcriptomic analysis based on LAB strains cultured on LJGO and 1H-NMR findings of LJGO residues after strain utilization showed that the GH13 gene cluster contains functional LAB genes involved in LJGO utilization. Further verification by gene knockout studies is needed to expand our findings.

Preparation and Structure Characterization of High-Value Laminaria digitata Oligosaccharides

Algae-derived marine oligosaccharides have been reported to be promising bioactive compounds because of their various properties with health benefits and potential significance in numerous applications in industrial biotechnology. In this study, laminaran oligosaccharides (LOs) with varying degrees of polymerization were obtained through partial acid hydrolysis of laminaran derived from Laminaria digitata. Based on response surface methodology, the optimum LOs yield was obtained for acid hydrolysis laminaran at a hydrolysis time of 55 min, temperature of 71°C, and acid concentration of 1.00 mol/L. The size-exclusion resin Bio-Gel P-2 was considered to be a better option for LOs purification. The structure of the purified oligosaccharides was analyzed through mass spectrometry and nuclear magnetic resonance. They demonstrated the main oligosaccharide structure corresponding to the connection of glucose with β-D-Glcp-(1→3)-β-D-Glcp, which was identified as laminaribiose (DP2), laminaritriose (DP3), laminaritetrose (DP4), and laminaripentaose (DP5). LOs demonstrate excellent antioxidant activities, as evidenced from their reactions with oxidizing free radicals, 1, 1-diphenyl-2-picryl-hydrazyl, and 2, 2′-azino-bis (3-etilbenzotiazoline-6-sulfonic acid) radicals. LOs exhibited a prebiotic effect on the growth of Bifidobacterium adolescentis and Lactobacillus plantarum. Therefore, we propose the development of LOs as natural antioxidants and prebiotics in the functional food and pharmaceutical industries.

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.

Gamma-Irradiation-Induced Degradation of the Water-Soluble Polysaccharide from Auricularia polytricha and Its Anti-Hypercholesterolemic Activity

The water-soluble polysaccharides (APPs) isolated from the edible mushroom Auricularia polytricha were irradiated by γ-ray at doses of 10, 100, and 1000 kGy. The effect of gamma irradiation on the degradation of the polysaccharide was investigated. After irradiation treatment, the viscosity and molecular weight of APPs decreased with the increase in the irradiation dose. The changes in the enthalpy of APPs after irradiation treatment were observed. Meanwhile, SEM showed that R-APPs were crushed into fragments and the surfaces became smooth and wrinkled after irradiation. In further spectrum analysis, it was found that the glycoside bonds of the polysaccharides were broken and accompanied by the formation of double bonds. This suggested that gamma irradiation could cause the depolymerization and oxidation of polysaccharides. In addition, irradiated APPs could reduce the body weight of hyperlipidemia mice. The levels of serum and liver TC, TG, and serum LDH-c significantly decreased in hyperlipidemia mice after treatment by irradiated APPs. It indicated that gamma irradiation significantly improved the anti-hypolipidemic activity of APPs. The relationship between the physicochemical properties and hypolipidemic activity of polysaccharides was interpreted, which provides a theoretical basis for the further development of APP products. Gamma irradiation is a viable technology for macromolecular modification for degradation.

Anti-hypertensive and cardioprotective activities of traditional Chinese medicine-derived polysaccharides: A review

Cardiovascular diseases (CVDs), a leading cause of death in modern society, have become a major public health issue globally. Although numerous approaches have been proposed to reduce morbidity and mortality, the pursuit of pharmaceuticals with more preventive and/or therapeutic value remains a focus of attention. Being a vast treasure trove of natural drug molecules, Traditional Chinese Medicine (TCM) has a long history of clinical use in the prophylaxis and remedy of CVDs. Increasing lines of preclinical evidence have demonstrated the effectiveness of TCM-derived polysaccharides on hindering the progression of CVDs, e.g. hypertension, myocardial infarction. However, to the best of our knowledge, there are few reviews on the application of TCM-derived polysaccharides in combating CVDs. Hence, we provide an overview of primary literature on the anti-hypertensive and cardioprotective activities of herbal polysaccharides. Additionally, we also discuss the current limitations and propose a new hypothesis about how polysaccharides exert cardiovascular effects based on the metabolism of polysaccharides.

Effect of γ-irradiation on the structure and antioxidant activity of polysaccharide isolated from the fruiting bodies of Morchella sextelata

The molecular weight of the polysaccharide and the chemical groups it contains has an important influence on its biological activity, relatively low molecular weight polysaccharides may have better antioxidant activity. Polysaccharides isolated from the fruiting bodies of Morchella sextelata (MSP) were treated by γ-irradiation at 10, 100 and 1000 kGy doses, and the physicochemical properties and antioxidant activity of irradiated MSP were investigated. Microscopic observation under a scanning electron microscope (SEM) showed that breakage and pores appeared on the surface of the irradiated polysaccharide. As the irradiation dose increased, the average molecular weight of MSP decreased significantly, while the particle size and thermal stability of MSP first increased at 10 and 100 kGy doses and then decreased at 1000 kGy doses. The antioxidant activities, measured by free radical scavenging tests and protective effect on PC12 cells injured by H₂O₂, were all increased after irradiation, especially when the concentration of MSP was low (50 and 100 μg/ml). Therefore, irradiation treatment was an effective method to enhance the activity of polysaccharides.

Anti-Photoaging and Potential Skin Health Benefits of Seaweeds

The skin health benefits of seaweeds have been known since time immemorial. They are known as potential renewable sources of bioactive metabolites that have unique structural and functional features compared to their terrestrial counterparts. In addition, to the consciousness of green, eco-friendly, and natural skincare and cosmetics products, their extracts and bioactive compounds such as fucoidan, laminarin, carrageenan, fucoxanthin, and mycosporine like amino acids (MAAs) have proven useful in the skincare and cosmetic industries. These bioactive compounds have shown potential anti-photoaging properties. Furthermore, some of these bioactive compounds have been clinically tested and currently available in the market. In this contribution, the recent studies on anti-photoaging properties of extracts and bioactive compounds derived from seaweeds were described and discussed.

Molar mass effect in food and health

It is demanded to supply foods with good quality for all the humans. With the advent of aging society, palatable and healthy foods are required to improve the quality of life and reduce the burden of finance for medical expenditure. Food hydrocolloids can contribute to this demand by versatile functions such as thickening, gelling, stabilising, and emulsifying, controlling texture and flavour release in food processing. Molar mass effects on viscosity and diffusion in liquid foods, and on mechanical and other physical properties of solid and semi-solid foods and films are overviewed. In these functions, the molar mass is one of the key factors, and therefore, the effects of molar mass on various health problems related to noncommunicable diseases or symptoms such as cancer, hyperlipidemia, hyperglycemia, constipation, high blood pressure, knee pain, osteoporosis, cystic fibrosis and dysphagia are described. Understanding these problems only from the viewpoint of molar mass is limited since other structural characteristics, conformation, branching, blockiness in copolymers such as pectin and alginate, degree of substitution as well as the position of the substituents are sometimes the determining factor rather than the molar mass. Nevertheless, comparison of different behaviours and functions in different polymers from the viewpoint of molar mass is expected to be useful to find a common characteristics, which may be helpful to understand the mechanism in other problems.

Functional polysaccharides of fucoidan, laminaran and alginate from Malaysian brown seaweeds (Sargassum polycystum, Turbinaria ornata and Padina boryana)

Brown seaweeds are rich source of functional polysaccharides that exhibit various bioactivities. However, Malaysian seaweeds are under-utilised, leading to low revenue throughout the supply chain of the seaweed industry. The aims of this study were to extract the functional polysaccharides, namely fucoidan (F), laminaran (L) and alginate (A) from Malaysian brown seaweeds (Sargassum polycystum, Turbinaria ornata and Padina boryana) and subsequently evaluate the properties of the extracted polysaccharides. P. boryana recorded the significantly (p ≤ 0.05) highest carbohydrate content (74.78 ± 1.63%) with highest fucoidan yield (Fpad = 1.59 ± 0.16%) while T. ornata contained significantly (p ≤ 0.05) highest alginate yield (Atur = 105.19 ± 3.45%). Water activities of these extracted polysaccharides varied from 0.63-0.71 with average score of browning indexes (~40). Fourier transform infrared (FTIR) spectroscopy analysis demonstrated that the extracted polysaccharides exhibited similar spectral pattern of spectra with the respective standards. Meanwhile, laminaran extracts showed the significantly highest (p ≤ 0.05) total phenolic contents (Lsar = 43.29 ± 0.43 mgGAE/g) and superoxide anion scavenging activity (Lsig = 21.7 ± 3.6%). On the other hand, the significantly highest (p ≤ 0.05) DPPH scavenging activity was recorded in alginate with Asar at 85.3 ± 0.8%. These findings reported the properties and bioactivities of natural polysaccharides from Malaysian brown seaweeds that revealed the potential to develop high-value functional ingredients from Malaysian brown seaweeds.

Gallic Acid-Laminarin Conjugate Is a Better Antioxidant than Sulfated or Carboxylated Laminarin

A 12.4 kDa laminarin (LM) composed of β(1→3)-glucan with β(1→6)-branches was extracted from brown seaweed Lobophora variegata and modified via carboxylation using dielectric barrier discharge (LMC), conjugation with gallic acid (LMG), and sulfation (LMS). Analyses of the chemical composition of LMC, LMG, and LMS yielded 11.7% carboxyl groups, 1.5% gallic acid, and 1.4% sulfate content, respectively. Antioxidant activities of native and modified laminarins were assessed using six different in vitro methods. Sulfation stopped the antioxidant activities of LM. On the other hand, carboxylation improved cooper chelation (1.2 times). LMG was found to be a more efficient antioxidant agent than LM in terms of copper chelation (1.3 times), reducing power (1.3 times), and total antioxidant capacity (80 times). Gallic acid conjugation was further confirmed using Fourier transform infrared spectroscopy (FT-IR) and one- and two-dimensional NMR spectroscopy analyses. LMG also did not induce cell death or affect the cell cycle of Madin–Darby canine kidney (MDCK) cells. On the contrary, LMG protected MDCK cells from H₂O₂-induced oxidative damage. Taken together, these results show that LMG has the potent antioxidant capacity, and, therefore, potential applications in pharmacological and functional food products.

Macroalgal dietary glycans: potential source for human gut bacteria and enhancing immune system for better health

Macroalgae are the diverse group of photosynthetic algae found at the intertidal regions of oceans. Recent advances suggest that macroalgal derived glycans have tremendous potential to maintain gut microbiome and immune system. The human gut bacteria harbor unique arsenals for utilizing a variety of macroalgal glycans, and produce a variety of oligosaccharides in vivo. Those oligosaccharides interact with immune cell receptors, and also are available for microbial fermentation, thus play magnificent roles in balancing the gut homeostasis. However, this area of research is still in infancy condition in term to understand their molecular interactions. For wooing this area, we urge to emphasize more studies on mechanistic level sympathetic of depolymerizing marine dietary glycans by gut bacteria and elucidating molecular aspect of glycans to cell receptors interactions. This will invent new nutraceutical strategies to purposefully manipulate the microbial composition to improve health. Therefore, review focuses on the recent development of mechanistic understanding of human gut bacterial communities for utilizing macroalgal derived glycans. Recent trends of application of glycans in modulating immune system at mechanistic level and their available evidences are discussed.

Laminarans and 1,3-β-D-glucanases

The laminarans are biologically active water-soluble polysaccharide (1,3;1,6-β-D-glucans) of brown algae. These polysaccharides are an attractive object for research due to its relatively simple structure, low toxicity, and various biological effects. 1,3-β-D-glucanases are an effective tool for studying the structure of laminarans, and can also be used to obtain new biologically active derivatives. This review is to outline what is currently known about laminarans and enzymes that catalyze of their transformation. We focused on information about sources, structure and properties of laminarans and 1,3-β-D-glucanases, methods of obtaining and structural elucidation of laminarans, and biological activity of laminarans and products of their enzymatic transformation. It has an increased focus on the immunomodulating and anticancer activity of laminarans and their derivatives.

A Critical Review of the Abilities, Determinants, and Possible Molecular Mechanisms of Seaweed Polysaccharides Antioxidants

Oxidative stress induces various cardiovascular, neurodegenerative, and cancer diseases, caused by excess reactive oxygen species (ROS). It is attributed to the lack of sufficient antioxidant defense capacity to eliminate unnecessary ROS. Seaweeds are largely cultivated for their edible and commercial purposes. Excessive proliferation of some seaweeds has occurred in coastal areas, causing environmental and economic disasters, and even threating human health. Removing and disposing of the excess seaweeds are costly and labor-intensive with few rewards. Therefore, improving the value of seaweeds utilizes this resource, but also deals with the accumulated biomass in the environment. Seaweed has been demonstrated to be a great source of polysaccharides antioxidants, which are effective in enhancing the antioxidant system in humans and animals. They have been reported to be a healthful method to prevent and/or reduce oxidative damage. Current studies indicate that they have a good potential for treating various diseases. Polysaccharides, the main components in seaweeds, are commonly used as industrial feedstock. They are readily extracted by aqueous and acetone solutions. This study attempts to review the current researches related to seaweed polysaccharides as an antioxidant. We discuss the main categories, their antioxidant abilities, their determinants, and their possible molecular mechanisms of action. This review proposes possible high-value ways to utilize seaweed resources.

Gamma-irradiation degraded sulfated polysaccharide from a new red algal strain Pyropia yezoensis Sookwawon 104 with in vitro antiproliferative activity

Pyropia yezoensis Sookwawon 104 is a newly cultivated strain of red marine algae. The present study aimed to investigate the in vitro antiproliferative activity of sulfated polysaccharide extracted from P. yezoensis Sookwawon 104 (PYSP), as well as that of its low molecular weight (Mw) derivatives. PYSP is a heterogeneous sulfated polysaccharide mainly composed of galactose, glucose and fucose. PYSP was degraded by gamma-irradiation at doses of 20 and 100 kGy to produce two derivatives, named as PYSP-20 and PYSP-100, respectively. Comparison of PYSP, PYSP-20 and PYSP-100 revealed clear differences in their molecular weight (Mw) distributions, and distinct in vitro antiproliferative activities against Hep3B, MDA-MB-231 and HeLa cancer cell lines. PYSP-20 and PYSP-100 exhibited stronger antiproliferative effects than PYSP, suggesting that the reduction in Mw may have increased the in vitro antiproliferative activity. Furthermore, the mRNA expression levels of the antitumor gene P53 and cell cycle-associated genes P21, Cyclin B1 and cyclin dependent kinase 1 (Cdk1) were further analyzed by reverse transcription-quantitative PCR in PYSP-20 and PYSP-100-treated cancer cells. PYSP and its derivatives were shown to inhibit the proliferation of tumor cells by regulating the expression of P53, P21, Cyclin B1 and Cdk1. In conclusion, low-Mw polysaccharide derivatives prepared from P. yezoensis Sookwawon 104 by gamma-irradiation exhibit significant inhibition effects on cancer cell proliferation in vitro and may be a novel source of potential anticancer therapeutic agents.

Recent Advances in Chain Conformation and Bioactivities of Triple-Helix Polysaccharides

Natural polysaccharides derived from renewable biomass sources are regarded as environmentally friendly and sustainable polymers. As the third most abundant biomacromolecule in nature, after proteins and nucleic acids, polysaccharides are also closely related with many different life activities. In particular, β-glucans are one of the most widely reported bioactive polysaccharides and are usually considered as biological response modifiers. Among them, β-glucans with triple-helix conformation have been the hottest and most well-researched polysaccharides at present, especially lentinan and schizophyllan, which are clinically used as cancer therapies in some Asian countries. Thus, creation of these active triple-helix polysaccharides is beneficial to the research and development of sustainable "green" biopolymers in the fields of food and life sciences. Therefore, full fundamental research of triple-helix polysaccharides is essential to discover more applications for polysaccharides. In this Review, the recent research progress of chain conformations, bioactivities, and structure-function relationships of triple-helix β-glucans is summarized. The main contents include the characterization methods of the macromolecular conformation, proof of triple helices, bioactivities, and structure-function relationships. We believe that the governments, enterprises, universities, and institutes dealing with the survival and health of human beings can expect the development of natural bioproducts in the future. Hence, a deep understanding of β-glucans with triple-helix chain conformation is necessary for application of natural medicines and biologics for a sustainable world.

Biomedical applications of laminarin

The ocean is par excellence a fertile territory of biodiversity on our planet. Marine-derived polysaccharides have been applied as functional materials in biomedicine due to their attractive bioactive properties, safety, high availability and low-cost production. Laminarin (or laminaran), a low molecular weight β-glucan storage polysaccharide present in brown algae, can be (bio-) chemically modified to enhance its biological activity and employed in cancer therapies, drug/gene delivery, tissue engineering, antioxidant and anti-inflammatory functions. This review provides a brief overview on laminarin characteristics, modification strategies and highlights its pivotal biomedical applications.

Storage stability of soluble pigments, chlorophylls, and carotenoids in electron-beam-irradiated edible lavers (Porphyra umbilicalis) with impact on microbial safety and sensory characteristics

BACKGROUND

In this study, we investigated whether electron beam (e-beam) irradiation can inactivate microbial populations, including aerobic bacteria plate count, fungi, and coliforms, in two types of lavers (dried and roasted). The impact of e-beam doses of 4 and 7 kGy on microbial populations, color values, total soluble pigments, chlorophylls, and carotenoid content immediately and after storage at 4, 15, 25, and 35 °C for 4, 8, and 12 weeks was also evaluated.

RESULTS

The initial microbial load of approximately 10⁶ and 10⁵  CFU g^-1 in both dried and roasted lavers was reduced to 10⁴ and 10¹  CFU g^-1 , respectively, after irradiation at 7 kGy. No further proliferation was observed in irradiated dried lavers during 4 weeks of storage at 4 and 15 °C. When stored at low temperature, the shelf-life was extended for up to 12 weeks in 7 kGy irradiated dried and roasted lavers. High amounts of soluble pigments and carotenoids were observed during storage in the 7 kGy irradiated dried laver samples at the end of 12 weeks irrespective of temperature. Although the chlorophyll content decreased under the storage conditions, it was comparatively stable in the 7 kGy-irradiated dried laver. Maximum degradation of color was observed in laver samples subjected to the roasting process.

CONCLUSION

Overall, this study indicated that e-beam irradiation of laver at 7 kGy maintains microbial safety as well as quality attributes during storage for up to 12 weeks. Further, dried laver had more essential compounds than roasted laver. © 2019 Society of Chemical Industry.

Laminarin enhances the quality of aged pig oocytes by reducing oxidative stress

Laminarin (LAM) is a β-glucan oligomer known to possess biological activities such as anticancer and antioxidant effects. This study explored the influence of LAM supplementation on in vitro aged porcine oocytes and the underlying mechanisms behind this influence. We found that LAM delayed the aging process and improved the quality of aged oocytes. LAM supplementation enhanced the subsequent developmental competence of aged oocytes during the in vitro aging process. The blastocyst formation rate was significantly increased in aged oocytes treated with 20 µg/ml LAM compared to non-treated aged oocytes (45.3% vs. 28.7%, P < 0.01). The mRNA levels of apoptosis-related genes, B cell lymphoma-2-associated X protein (Bax) and Caspase-3, were significantly lower in blastocysts derived from the LAM-treated aged oocytes during the in vitro aging process. Furthermore, the level of intracellular reactive oxygen species was significantly decreased and that of glutathione was significantly increased in aged oocytes following LAM treatment. Mitochondrial membrane potential was increased, and the activities of caspase-3 and cathepsin B were significantly reduced in the LAM-treated aged oocytes compared with the non-treated aged oocytes. Taken together, these results suggest that LAM is beneficial for delaying the aging process in porcine oocytes.

Antioxidant, antibacterial and in vivo wound healing properties of laminaran purified from Cystoseira barbata seaweed

Laminaran, a polysaccharide extracted from marine algae, exhibits attractive properties being non-toxic, hydrophilic and biodegradable. The aim of this study was to investigate the effectiveness of a cream based on the brown seaweed Cystoseira barbata laminaran (CBL) for healing full thickness wounds induced on rats. The antibacterial activity of CBL was evaluated against Gram positive and Gram negative bacteria and the antioxidant properties were assessed using five different assays. To highlight the healing effectiveness of CBL-based cream, the response to treatment was assessed by macroscopic, histologic and biochemical parameters and was compared to controls. CBL, recovered (7.27%) by ultrafiltration (1-10 kDa) and predominantly consisted of (1 → 3)-linked β-d-glucopyranose residues with a small level of (1 → 6)-glycosidic bonds, showed noticeable antioxidant and antibacterial properties. The cream containing CBL as an active ingredient exerted a promoting healing effect. The wound contraction reached 98.57 ± 1.31% after thirteen days of treatment. The derma in CBL treated group is properly arranged and revealed an improved collagen deposition and an increased fibroblast and vascular densities compared with the control groups. Overall, these results established, for the first time, a scientific in vivo evidence of the efficiency of CBL as a wound healing agent of interest in modern medicine.

Effect of gamma irradiation on structure, physicochemical and immunomodulatory properties of Astragalus polysaccharides

Astragalus polysaccharides (APS) were treated with different gamma irradiation doses (10, 25, 50, 100 and 150 kGy) to investigate the effects of gamma radiation processing on structure, physicochemical and immunomodulatory properties. The results revealed both the number-average and weight-average molecular weight of APS significantly decreased with increasing irradiation dose, whereas the solubility was increased after irradiation. A decrease in the apparent viscosity, as well as an increase in amount of small fragments of APS granules was also observed with increasing irradiation dose. FT-IR spectra indicated that gamma irradiation introduced no significant changes into the functional group status of APS. High irradiation dose (>50 kGy) caused a significant increase of yellowness and a slightly decrease of thermal stability of APS. Further, the immunomodulatory activity of irradiated APS was evaluated on Caco2 cells. APS irradiated at dose of 25 kGy exhibited the highest ability to induce nitric oxide production and up-regulate the mRNA expression of inflammatory cytokines, occludin, zonula occludens protein-1 (ZO-1) and toll-like receptor 4 (TLR4), as well as the protein expression of ZO-1 and TLR4. These findings indicate that gamma irradiation modification with a proper dose enhance immunomodulatory activity of APS by improving physicochemical properties without changing the functional groups.

Enzymatic properties and the gene structure of a cold-adapted laminarinase from Pseudoalteromonas species LA

We isolated a laminarin-degrading cold-adapted bacterium strain LA from coastal seawater in Sagami Bay, Japan and identified it as a Pseudoalteromonas species. We named the extracellular laminarinase LA-Lam, and purified and characterized it. LA-Lam showed high degradation activity for Laminaria digitata laminarin in the ranges of 15-50°C and pH 5.0-9.0. The major terminal products degraded from L. digitata laminarin with LA-Lam were glucose, laminaribiose, and laminaritriose. The degradation profile of laminarioligosaccharides with LA-Lam suggested that the enzyme has a high substrate binding ability toward tetrameric or larger saccharides. Our results of the gene sequence and the SDS-PAGE analyses revealed that the major part of mature LA-Lam is a catalytic domain that belongs to the GH16 family, although its precursor is composed of a signal peptide, the catalytic domain, and three-repeated unknown regions.

Magnetic graphene oxide modified by imidazole-based ionic liquids for the magnetic-based solid-phase extraction of polysaccharides from brown alga

Magnetic graphene oxide was modified by four imidazole-based ionic liquids to synthesize materials for the extraction of polysaccharides by magnetic solid-phase extraction. Fucoidan and laminarin were chosen as the representative polysaccharides owing to their excellent pharmaceutical value and availability. Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, and thermogravimetric analysis were applied to characterize the synthesized materials. Single-factor experiments showed that the extraction efficiency of polysaccharides was affected by the amount of ionic liquids for modification, solid-liquid ratio of brown alga and ethanol, the stirring time of brown alga and ionic liquid-modified magnetic graphene oxide materials, and amount of 1-(3-aminopropyl)imidazole chloride modified magnetic graphene oxide materials added to the brown alga sample solution. The results indicated that 1-(3-aminopropyl)imidazole chloride modified magnetic graphene oxide possessed better extraction ability than graphene oxide, magnetic graphene oxide, and other three ionic-liquid-modified magnetic graphene oxide materials. The highest extraction recoveries of fucoidan and laminarin extracted by 1-(3-aminopropyl)imidazole chloride modified magnetic graphene oxide were 93.3 and 87.2%, respectively. In addition, solid materials could be separated and reused easily owing to their magnetic properties.