Polysaccharides from Laminaria japonica: Structural characteristics and antioxidant activity

Ultrasonic-assisted extraction, analysis and properties of purple mangosteen scarfskin polysaccharide and its acetylated derivative

Purple mangosteen scarfskin polysaccharide has many important physiological functions, but its preparation method, structure, and function need further exploration. A polysaccharide was obtained from mangosteen scarfskin by ultrasonic-assisted extraction and purified. On this basis, its structure and physicochemical properties were investigated. The Congo red experiment was used to determine whether it has a triple helix conformation. The structure of purple mangosteen scarfskin polysaccharide was further analyzed by infrared spectroscopy and nuclear magnetic analysis. The antioxidant activities of the above three polysaccharides were studied by related experiments. It was found that the monosaccharide composition of purple mangosteen scarfskin polysaccharide mainly contained a large amount of arabinose, a small amount of rhamnoose and a very small amount of galacturonic acid, and its core main chain was composed of 1,4-α-arabinose. It did not have this spatial configuration. After the acetylation of purple mangosteen scarfskin polysaccharide, the acetylated derivative with a degree of substitution of 0.33 was obtained. It was found that they had certain scavenging and inhibiting effects on hydroxyl radicals and lipid peroxidation, and their activities were related to the concentration of polysaccharides. Meanwhile, the antioxidant activity of the polysaccharide was significantly enhanced after the modified treatment of acetylation, which indicated that chemical modification could effectively improve some activities of polysaccharide. The above studies provided some reference value for the further research and development of purple mangosteen scarfskin polysaccharide.

Antioxidant activity of polysaccharide from Garcinia mangostana rind and their derivatives

BACKGROUND

Polysaccharide from Garcinia mangostana rind has many biological activities and deserves further research.

METHODS

The antioxidant properties of UAEE-GMRP, UAEE-GMRP-1 A, CM-30, and Ac-30 were evaluated through two different antioxidant activity experimental systems.

RESULTS

The four polysaccharides had a better scavenging effect on hydroxyl radicals, while their inhibitory effect on lipid peroxidation was relatively weak. However, overall, the four polysaccharides showed a certain degree of potential application in the two antioxidant experiments mentioned above, especially the chemically modified polysaccharides from Garcinia mangostana rind, which effectively improved their antioxidant activity. This also indicates that chemical modification is a better method to improve polysaccharide activity. In addition, in these two antioxidant exploration experiments, carboxymethylated polysaccharide showed stronger activity compared to the other three polysaccharides.

CONCLUSION

The carboxymethylation modification may have great potential for application.

Contribution of phospholipase B to the formation of characteristic flavor in steamed sturgeon meat

Sensory analysis and untargeted lipidomics were employed to study the impact of phospholipase B (PLB) on lipid oxidation and flavor in steamed sturgeon meat, revealing the inherent relationship between lipid oxidation and flavor regulation. The research verified that PLB effectively suppresses fat oxidation and improves the overall taste of steamed sturgeon meat. Furthermore, the PLB group identified 52 compounds, and the content of odor substances such as isoamyl alcohol and hexanal was reduced compared with other groups. Finally, lipid substances containing eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) were screened out from 32 kinds of differential phospholipids. Through Pearson correlation analysis, it was observed that certain differential phospholipids such as PC (22:6) and PC (22:5) exhibited varying correlations with odor substances like hexanal and isovaleraldehyde. These findings suggest that PLB specifically affects certain phospholipids, leading to the production of distinct volatile substances through oxidative degradation.

Characterization of Three Polysaccharide-Based Hydrogels Derived from Laminaria japonica and Their Hemostatic Properties

Three Laminaria japonica polysaccharides (LJPs) extracted via water extraction (LJP-W), acid extraction (LJP-A), and enzymatic extraction (LJP-E) were used as raw materials to be cross-linked with chitosan and polyvinyl alcohol to prepare hydrogels. Compared with conventional hydrogel systems, all three types of LJP-based polysaccharide hydrogels exhibited better swelling properties (14 times their original weight) and the absorption ability of simulated body fluid (first 2 h: 6-10%). They also demonstrated better rigidity and mechanical strength. Young's modulus of LJP-E was 4 times that of the blank. In terms of hemostatic properties, all three polysaccharide hydrogels did not show significant cytotoxic and hemolytic properties. The enzyme- and acid-extracted hydrogels (LJP-Gel-A and LJP-Gel-E) demonstrated better whole-blood coagulant ability compared with the water-extracted hydrogel (LJP-Gel-W), as evidenced by the whole blood coagulation index being half that of LJP-Gel-W. Additionally, the lactate dehydrogenase viabilities of LJP-Gel-A and LJP-Gel-E were significantly higher, at about four and three times those of water extraction, respectively. The above results suggested that LJP-Gel-A and LJP-Gel-E exhibited better blood coagulation capabilities than LJP-Gel-W, due to their enhanced platelet enrichment and adhesion properties. Consequently, these hydrogels are more conducive to promoting coagulation and have good potential for wound hemostasis.

Response Surface Optimization of Polysaccharides from Jaboticaba (Myrciaria cauliflora [Mart.] O.Berg) Fruits: Ultrasound-Assisted Extraction, Structure Properties, and Antioxidant/Hypoglycemic Activities

Ultrasound-assisted extraction (UAE) method proves to be more effective compared to traditional extraction methods. In the present study, response surface methodology (RSM) was used to determine the optimal process parameters for extracting polysaccharides (U-MCP) from jaboticaba fruit using UAE. The optimum extraction conditions were ultrasonic time 70 min, extraction temperature 60 °C, and power 350 W. Under these conditions, the sugar content of U-MCP was 52.8 %. The molecular weights of the ultrasound-assisted extracted U-MCP ranged from 9.52×102 to 3.27×103  Da, and consisted of five monosaccharides including mannose, galacturonic acid, glucose, galactose, and arabinose. Moreover, in vitro antioxidant and hypoglycaemic assay revealed that U-MCP has prominent anti-oxidant activities (1,1-diphenyl-2-picryl-hydrazyl (DPPH) radicals, hydroxyl radicals and 2,2'-Azinobis (3-ethylbenzothiazoline-6-sulfonic Acid Ammonium Salt) (ABTS) radicals scavenging activities) and hypoglycemic activities (α-amylase and α-glucosidase inhibition activities).

Effect of hydrochloric acid and citric acid with ultrasound processing on characteristics of superfine-ground pectic polysaccharides from okra (Abelmoschus esculentus L.) peel

The structural properties and biological activities of okra pectic polysaccharides (OPs) were impacted by various extraction methods. Based on commonly grinding (40, 100 meshes) and superfine grinding okra powders, two extraction solvents (hydrochloric acid, HA; citric acid, CA) were used firstly. Next, the extraction yield, physical and chemical properties, molecular structure and functional properties of OPs were analyzed by non-ultrasonic treatment and ultrasound-assisted superfine grinding method. The outcomes demonstrated that the extraction yield of OPs rose as the particle size of the powder decreased. HA-OPs had higher molecular weight (Mw), apparent viscosity and emulsification ability than CA-OPs. CA-OPs had higher esterification degree (DE), solubility and total sugar content, and higher amounts of rhamnogalacturonan-I (RG-I) segments. Compared with OPs without ultrasound-assisted extraction, ultrasound-assisted superfine grinding extraction exhibited higher sugar content, antioxidant capacity, emulsification ability, lower Mw, DE and apparent viscosity. Finally, the correlation between structure and function of OPs was further quantified. The antioxidant capacity was positively correlated with RG-I content, and negatively correlated with DE and Mw. The emulsification ability was mainly positively correlated with the GlcA of OPs. This study provides a theoretical basis for the development of OPs foods with clear structure-function relationship, which would be instructive for the application of OPs in food and cosmetics.

Physicochemical characterization and cosmetic application of kelp blanching water polysaccharides

Seaweeds account for half of global mariculture and have become a key player in bio-based industries. Seaweed process typically starts with hot water blanching that helps reduce postharvest quality deterioration but also generates large amounts of hydrothermal waste. This study aims to explore the feasibility of isolating water-soluble biopolymers from seaweed hydrothermal waste and their potential applications. Using Saccharina japonica (formerly Laminaria japonica) blanching water as example, 2.9 g/L of polymeric substances were efficiently isolated by ultrafiltration, implying biopolymer coproduction potential of ~5.8 kt from blanching wastewater of current kelp industry. Physicochemical characterizations revealed polysaccharidic nature of the biopolymers, with high contents of fucose, uronic acids and sulfate, showing distinct but also overlapping structural features with hot water-extracted kelp polysaccharides. The main fraction of the blanching water polymers after anion exchange chromatography was acidic polysaccharide, the major backbone residues of which were (1-4) linked mannopyranose, (1-4) linked gulopyranose and (1-2) linked fucopyranose while the branched residues were primarily 1,3,4-, 1,2,4- and 1,4,6-linked hexoses but also 1,3,4-fucopyranose. Furthermore, the polysaccharides were found to have a good compatibility in cosmetic creams with added cohesiveness and freshness, demonstrating the application potential of such natural biopolymers from currently underexplored seaweed blanching water.

Extraction, Isolation, Screening, and Preliminary Characterization of Polysaccharides with Anti-Oxidant Activities from Oudemansiella raphanipies

Response surface methodology (RSM) was used to find the optimal extraction process of Oudemansiella raphanipies polysaccharides (ORPs). The results showed that the optimal extraction parameters were an alkali concentration of 0.02 mol/L, a ratio of material to liquid of 1:112.7 g/mL, an extraction temperature of 66.0 °C, and an extraction time of 4.0 h. Under the optimal conditions, the yield of ORPs was raised to 16.2 ± 0.1%. The antioxidant activities of ORPs-I~V were determined and compared, and ORPs-V was further purified by chromatography, with an average molecular weight (Mw) of 18.86 kDa. The structure of ORPs-V was determined by Fourier transform-infrared spectroscopy (FT-IR), monosaccharide analysis, and nuclear magnetic resonance (NMR) spectroscopy. The ORPs-V comprised fucose, rhamnose, arabinose, glucose, galactose, mannose, xylose, fructose, galacturonic acid, and glucuronic acid at a ratio of 1.73:1.20:1.13:2.87:8.71:2.89:1.42:0.81. Compared to other ORPs, ORPs-V showed the strongest antioxidant activities (ABTS radical cation, hydroxyl radical and DPPH scavenging activities, and reducing power), and were able to significantly increase the activities of superoxide dismutase, catalase, lactate dehydrogenase, and glutathione peroxidase. However, they reduced the malondialdehyde content in mice fed a high-fat diet. These results indicate that ORPs-V may be good anti-oxidant agents to be applied in functional foods.

Structural Characterization, Rheological Properties, Antioxidant and Anti-Inflammatory Activities of Polysaccharides from Zingiber officinale

The structural characteristics, rheological properties, antioxidant and anti-inflammatory activities of Zingiber officinale polysaccharides (ZOP) and ZOP-1 were studied. The total soluble sugar contents of ZOP and ZOP-1 were 78.6 ± 0.6 and 79.4 ± 0.4%, respectively. Compared with ZOP, ZOP-1 had a larger molecular weight and a more uniform distribution. There were also some differences in the monosaccharide composition between ZOP and ZOP-1. The main monosaccharide of ZOP and ZOP-1 was glucose (Glc) and galactose (Gal), respectively. Ultraviolet visible spectroscopy (UV-Vis) and fourier transform infrared spectra (FT-IR) results showed that the two polysaccharides had the characteristic absorption peaks of polysaccharides and did not contain nucleic acid and protein. They had good thermal stability, trihelix structure and amorphous sheet structure. ZOP and ZOP-1 had obvious differences in microstructure. The surface of ZOP was smooth and the broken structure was compact and stable with angular shape, while the surface of ZOP-1 was uneven with spiral accumulation and not closely arranged. Moreover, ZOP and ZOP-1 were polysaccharides molecular polymers which were entangled by van der waals' force (VDW) between polysaccharides molecules and hydrogen bond association between sugar chains, and both contain α pyranose. At different concentrations, temperature, pH and salt ion concentrations, both ZOP and ZOP-1 had the properties of non-Newtonian fluids, showed shear dilution phenomenon, which had the potential as a texture modifier or thickener in food or biomedicine. Compared with ZOP, ZOP-1 showed superior antioxidant and anti-inflammatory activities in vitro.

Biochemical characterization and anti-cancer activity of tangential flow filtration system assisted purification of fucoglucan from Laminaria japonica

Polysaccharide from Laminaria japonica (LJPS) exhibits multiple biological functions. However, we found that crude LJPS doesn't show good anti-lung cancer activity in this study. We therefore used tangential flow filtration (TFF) system to optimize the anticancer activity of LJPS. We divided the crude LJPS into two fractions by TFF system with a 10 kDa filter and denoted as retentate (10K-R) and filtration (10K-F). The chemical assay revealed that the main molecular mass of 10K-R and 10K-F is about 985 and 3 kDa, respectively. The main components of 10K-R include fucose (19.3 %), and glucose (59.5 %); while glucose (88.6 %) is a major component of 10K-F. Biological functions showed that 10K-R but not 10K-F inhibited the viability and mobility of cancer cells. 10K-R downregulated expressions of transforming growth factor β receptor and Slug, and inhibited intracellular signaling molecules, including FAK, AKT, ERK1/2, and Smad2. This study is the first concept to purify the polysaccharide by TFF system and showed the potential mechanism of 10K-R inhibited cancer cells.

Effect of Ultrasonic Irradiation on the Physicochemical and Structural Properties of Laminaria japonica Polysaccharides and Their Performance in Biological Activities

Due to the large molecular weight and complex structure of Laminaria japonica polysaccharides (LJP), which limit their absorption and utilization by the body, methods to effectively degrade polysaccharides had received more and more attention. In the present research, hot water extraction coupled with three-phase partitioning (TPP) was developed to extract and isolate LJP. Ultrasonic L. japonica polysaccharides (ULJP) were obtained by ultrasonic degradation. In addition, their physicochemical characteristics and in vitro biological activities were investigated. Results indicated that ULJP had lower weight-average molecular weight (153 kDa) and looser surface morphology than the LJP. The primary structures of LJP and ULJP were basically unchanged, both contained α-hexo-pyranoses and were mainly connected by 1,4-glycosidic bonds. Compared with LJP, ULJP had stronger antioxidant activity, α-amylase inhibitory effect and anti-inflammatory effect on RAW264.7 macrophages. The scavenging rate of DPPH free radicals by ULJP is 35.85%. Therefore, ultrasonic degradation could effectively degrade LJP and significantly improve the biological activity of LJP, which provided a theoretical basis for the in-depth utilization and research and development of L. japonica in the fields of medicine and food.

Antioxidant and anti-aging activities of Laminaria japonica polysaccharide in Caenorhabditis elegans based on metabonomic analysis

In this study, Laminaria japonica polysaccharide (LJP) was measured in vitro against three antioxidant indicators: DPPH, ABTS, and hydroxyl. In vivo, LJP investigated thermal tolerance, H2O2-induced oxidative stress tolerance, and lipofuscin in Caenorhabditis elegans (C. elegans). Following that, after LJP treatment, the effects and underlying mechanisms were investigated at the mRNA and metabolite levels. We discovered the free radical scavenging activity of LJP. The thermal tolerance of C. elegans improved significantly, lowering levels of malondialdehyde, lipofuscin, and reactive oxygen species. Upregulation of Glp-1, Daf-16, Skn-1, and Sod-3 expression and downregulation of Age-1 and Daf-2 expression increased the ability to resist oxidative stress. Metabolomic analysis revealed that LJP promoted alanine, aspartate, and glutamate metabolism, the TCA cycle, butanoate metabolism, and the FOXO signaling pathway expression, resulting in significant changes in (R)-3-hydroxybutyric acid, palmitic acid, L-glutamic acid, L-malic acid, and oleic acid. The present study shows that LJP, as a functional food, has the potential to boost antioxidant capacity and delay aging.

Recent advances in medicinal and edible homologous polysaccharides: Extraction, purification, structure, modification, and biological activities

110 kinds of traditional Chinese medicines can be used for medicine and food from Chinese pharmacopoeia in 2021. With the deepening of research in recent years, medicinal and edible homologous (MEH) traditional Chinese medicines have great development and application prospects in many fields. Polysaccharides are one of the major and representative pharmacologically active macromolecules in traditional Chinese medicines with MEH. Moreover, traditional Chinese medicines with MEH have become the main source of natural polysaccharides with safety, high efficiency, and low side effects. Increasing researches have confirmed that MEH polysaccharides (MEHPs) have multiple biological activities both in vitro and in vivo methods, such as antioxidant, immunomodulatory, anti-tumor, anti-aging, anti-inflammatory, hypoglycemic, hypolipidemic activities, and regulating intestinal flora. Additionally, different raw materials, extraction, purification, and chemical modification methods result in differences in the structure and biological activities of MEHPs. The purpose of the present review is to provide comprehensively and systematically reorganized information in the extraction, purification, structure, modification, biological activities, and potential mechanism of MEHPs to support their therapeutic effects and health functions. New valuable insights and theoretical basis for the future researches and developments regarding MEHPs were proposed in the fields of medicine and food.

Physicochemical and antioxidant properties of Lycium barbarum seed dreg polysaccharides prepared by continuous extraction

Lycium barbarum seed dreg polysaccharides (LBSDPs) were continuously extracted with four different solvents [hot buffer (HBSS), chelating agent (CHSS), dilute alkaline (DASS), and concentrated alkaline (CASS)]. The present study characterized the physicochemical and anti-oxidant based functional properties of different LBSDPs. The monosaccharide analysis revealed xylose (64.63%, 70.00%, 44.71%, and 66.67%) as the main sugar with the molecular weights of 5985, 7062, 5962, and 8762 Da in HBSS, CHSS, DASS, and CASS, respectively. Among the four polysaccharides, CASS had the strongest DPPH radical scavenging ability and reducing power; while, CHSS had the strongest ferrous ions chelating ability and HBSS showed the strongest OH radical scavenging ability. In terms of functional properties, HBSS and CASS had better solubility and oil holding capacity, while, CASS and CHSS had higher foam capacity and foam stability. Altogether, the polysaccharides extracted from L. barbarum seed dreg exhibit a potential application prospect in functional food and cosmetics industries.

Extraction, structure, and activity of polysaccharide from Radix astragali

Radix astragali polysaccharide (RAP) is a water-soluble heteropolysaccharide. It is an immune promoter and regulator, and has antivirus, antitumor, anti-aging, anti-radiation, anti-stress, anti-oxidation and other activitys. The extraction, separation, purification, structure, activity and modification of RAP were summarized. Some extraction methods of RAP had been introduced, and the separation and purification methods of RAP were reviewed, and the structure and activity of RAP were highly discussed. Current derivatization of RAP was outlined. Through the above discussion that the yield of crude polysaccharides from Radix astragali by enzyme-assisted extraction was significantly higher than that by other extraction methods, but each extraction method had different extraction effects under certain conditions, and the activity efficiency of RAP was also different. Therefore, it is particularly important to optimize the extraction method with known better yield for the study of RAP. In addition, the purification and separation of RAP are the key factors affecting the yield and activity of RAP. At the same time, there are still few studies on the derivatiration of Radix astragali polysaccharide, but the researches in this area are very important. RAP also has many important pharmacological effects on human body, but its practical application needs further study. Finally, studies on the structure-activity relationship of RAP still need to be carried out by many scholars. This review would provide some help for further researches on various important applications of RAP.

Comparison of the immune activation capacities of fucoidan and laminarin extracted from Laminaria japonica

Laminaria japonica is a brown alga and is composed primarily of polysaccharides. Fucoidan and laminarin are the major polysaccharides of L. japonica and exhibit biological activities, including immune modulation and anti-coagulant and antioxidant effects in animals and humans. In this study, we evaluated the ability of fucoidan and laminarin from L. japonica to induce immune cell activation and anti-cancer immunity, which has not yet been studied. The injection of fucoidan to mice promoted the upregulation of major histocompatibility complex and surface activation molecules in splenic dendritic cell subsets, whereas laminarin showed a weaker immune activation ability. In addition, fucoidan treatment elicited inflammatory cytokine production; however, laminarin did not induce the production of these cytokines. Regarding cytotoxic cell activities, fucoidan induced the activation of lymphocytes, including natural killer and T cells, whereas laminarin did not induce cell activation. Finally, fucoidan enhanced the anticancer efficacy of anti-programmed Death-Ligand 1 (PD-L1) antibody against Lewis lung carcinoma, whereas laminarin did not promote the cancer inhibition effect of anti-PD-L1 antibody. Thus, these data suggest that fucoidan from L. japonica can be used as an immune stimulatory molecule to enhance the anticancer activities of immune checkpoint inhibitors.

Structural Characteristics and Immunomodulatory Effects of a Long-Chain Polysaccharide From Laminaria japonica

Polysaccharides derived from Laminaria japonica (LJPS) have shown a variety of beneficial effects on improving human health; however, the structural features and bioactivities of long-chain LJPS remain unclear. This study aimed to investigate the structural characteristics and bioactivities of a novel long-chain LJPS. Results showed that the LJPS was composed of Fuc, Rha, Ara, Gal, Glc, Xyl, Man, Fru, Rib, GalA, GluA, GlcA, and ManA, with a molar ratio of 35.71:1.48:0.28:13.16:0.55:2.97:6.92:0.58:0.41:0.14:3.16:15.84:18.79. Of these, Fuc, Gal, Man, GlcA, and ManA were the predominant components with an accumulated proportion of 93.6%. The LJPS was found to consist of seven types of the monomer residues, and the main interchain glycosidic linkages were β -D-(1 → 2), α -D-(1 → 3), (1 → 4), and (1 → 6), and the molecular mass was 5.79 × 10⁴ g/mol. Regarding the molecular conformation, LJPS was a multi-branched, long-chain macromolecule, and appeared in a denser crosslinking network with highly branched and helix domains in the terms of morphology. Additionally, the LJPS had no toxicity to mouse macrophage cells and exhibited biphasic immuno-modulating capacity. The present findings suggested that the long-chain LJPS might be an attractive candidate as an immunopotentiating and anti-inflammatory functional food, and this study also provides a feasible approach to decipher the structural characteristics and spatial conformations of plant-derived polysaccharides.

Effects of multi-frequency ultrasonic on the physicochemical properties and bioactivities of polysaccharides from different parts of ginseng

The effect of multi-frequency ultrasonic extraction (MUE) on the yields, physicochemical properties, antioxidant and α-glucosidase inhibitory activities of polysaccharides (GPs) from different parts of ginseng were compared. Results demonstrated that yields of polysaccharides from different parts were found to vary significantly differences, in the order of roots (M-GRPs) > flowers (M-GFPs) > leaves (M-GLPs). Compared with heat reflux extraction, MUE not only increased the yield of GPs by up to 9.14%-210.87%, with higher uronic acid content (UAC: increased by 4.99%-53.48%), total phenolics content (TPC: increased by 7.60% to 42.61%), total flavonoids content (TFC: increased by 2.52%-5.45%), and lower molecular weight (Mw: reduced by 6.51%- 33.08%) and protein content (PC: reduced by 5.15%-8.95%), but also improved their functional properties and bioactivities. All six purified polysaccharides extracted by MUE were acidic pyran polysaccharide with different monosaccharide composition, possessed remarkable antioxidant and α-glucosidase inhibitory activities. Especially, M-GFP-1 exhibited the highest bioactivities, illustrated that the activities were highly correlated with UAC and TPC, Mw, and triple helical structure. These results indicate that MUE was an efficient technique for improving yields, physicochemical and functional properties and enhancing biological activities of polysaccharide.

Isolation, structural characterization and bioactivities of polysaccharides from Laminaria japonica: A review

Laminaria japonica is a familiar marine plant and is often used as food due to its abundant carbohydrates, vitamins and minerals. As one of the main types of active substances in L. japonica, polysaccharides are widely used in the food and chemical industries and in medicine and healthcare due to their health benefits, such as immunoregulatory, antioxidant, and antidiabetic effects. However, there has been no systematic summary of the isolation, structural characterization and bioactivities of L. japonica polysaccharides (LJPs). Therefore, the present review includes a survey of extraction and purification methods for these bioactive molecules, along with a dissertation on the structural characterization of the carbohydrate components. Moreover, an overview of the most recent results related to LJP biological activities is provided. This review provides a useful reference for further research, production, and application of LJPs in functional foods and therapeutic agents.

Enzymatic Preparation of Low-Molecular-Weight Laminaria japonica Polysaccharides and Evaluation of Its Effect on Modulating Intestinal Microbiota in High-Fat-Diet-Fed Mice

Recent studies have shown that seaweed polysaccharides can ameliorate high-fat-diet (HFD)-induced metabolic syndromes associated with the regulatory function of gut microbiota. However, kelp, a natural source of seaweed polysaccharides, is highly viscous, making it difficult to prepare dietary fiber by simple degradation. Therefore, we developed a novel method of preparing low-molecular-weight polysaccharides from Laminaria japonica by combining high-pressure pretreatment and composite enzymatic degradation and evaluated the obesity prevention activity of these polysaccharides. Seaweed L. japonica polysaccharides (SJP) were rapidly utilized by the human fecal microbiota in vitro, resulting in the generation of short-chain fatty acids (SCFAs), specifically acetate and propionate. The in vivo effects of SJP on the intestinal microbiota were also investigated using HFD-fed C57BL/6J mice. SJP reduced weight gain and fat deposition in HFD-fed mice and increased the concentration of total SCFAs, including acetate, propionate, and butyrate in the feces. SJP ameliorated HFD-induced gut microbiota dysbiosis, resulting in increased abundance of Faecalibaculum, Romboutsia, and Clostridium sensu stricto 1 and decreased abundance of Blautia and Lactobacillus. Further, SJP enhanced the abundance of Akkermansia muciniphila in mice provided with HFD and normal chow. Single-strain culture experiments also revealed that SJP promoted the growth of A. muciniphila. This study highlights the potential use of SJP, prepared using composite enzymatic degradation (cellulase and recombinant alginate lyase), in preventing obesity and restoring intestinal homeostasis in obese individuals.

Soluble Polysaccharide Derived from Laminaria japonica Attenuates Obesity-Related Nonalcoholic Fatty Liver Disease Associated with Gut Microbiota Regulation

In this study, the effects of a polysaccharide derived from Laminaria japonica (LJP) on obesity were investigated in mice fed a high-fat diet (HFD). LJP significantly attenuated obesity-related features, lowering serum triglycerides, glucose, total cholesterol and low-density lipoprotein cholesterol levels. HFD-induced liver steatosis and hepatocellular ballooning were significantly attenuated by LJP. Additionally, LJP was found to significantly modulate hepatic gene expressions of AMPK and HMGCR, which are key regulators of lipid and cholesterol metabolism. We further found that LJP ameliorated HFD-induced gut microbiota (GM) dysbiosis by significantly reducing the obesity-related Firmicutes to Bacteroidetes ratio, meanwhile promoting the growth of Verrucomicrobia at the phylum level. At the genus level, propionate-producing bacteria Bacteroides and Akkermansia were elevated by LJP, which might explain the result that LJP elevated fecal propionate concentration. Taken together, these findings suggest that dietary intake of LJP modulates hepatic energy homeostasis to alleviate obesity-related nonalcoholic fatty liver disease associated with GM regulation.

Composition-Activity Relationships of Polysaccharides from Saccharina japonica in Regulating Gut Microbiota in Short-Term High-Fat Diet-Fed Mice

Saccharina japonica polysaccharide could modulate gut microbiota composition; however, the composition-activity relationship remains unclear, thus restricting its application. In the current study, we investigated the impact of eight different S. japonica polysaccharide fractions on the gut microbiota after day 2 and day 14 treatments on high-fat diet (HFD) feeding mice. The results showed that a 2 day HFD dramatically altered gut microbiota composition, and the additional 12 day HFD further strengthened the gut microbiota dysbiosis in the HFD group. LjA-1 and LjA-3 could partially alleviate the dysbiosis of gut microbiota composition and significantly alter gut microbiota function. Multiple linear regression analysis revealed that the sulfate content and the molecular weight distributions were the main factors affecting the dominant gut bacterial genera. Our findings reveal that gut microbiota homeostasis could be disordered by HFD at day 2 and provide insights into the quantitative composition-activity relationships of polysaccharides in regulating gut microbiota.

Regulation of Laminaria Polysaccharides with Different Degrees of Sulfation during the Growth of Calcium Oxalate Crystals and their Protective Effects on Renal Epithelial Cells

The original Laminaria polysaccharide (LP0) was sulfated using the sulfur trioxide-pyridine method, and four sulfated Laminaria polysaccharides (SLPs) were obtained, namely, SLP1, SLP2, SLP3, and SLP4. The sulfated (-OSO3 -) contents were 8.58%, 15.1%, 22.8%, and 31.3%, respectively. The structures of the polysaccharides were characterized using a Fourier transform infrared (FT-IR) spectrometer and nuclear magnetic resonance (NMR) techniques. SLPs showed better antioxidant activity than LP0, increased the concentration of soluble Ca2+ in the solution, reduced the amount of CaOx precipitation and degree of CaOx crystal aggregation, induced COD crystal formation, and protected HK-2 cells from damage caused by nanometer calcium oxalate crystals. These effects can inhibit the formation of CaOx kidney stones. The biological activity of the polysaccharides increased with the content of -OSO3 -, that is, the biological activities of the polysaccharides had the following order: LP0 < SLP1 < SLP2 < SLP3 < SLP4. These results reveal that SLPs with high -OSO3 - contents are potential drugs for effectively inhibiting the formation of CaOx stones.

Molecular Mechanism of Anti-Inflammatory Activities of a Novel Sulfated Galactofucan from Saccharina japonica

Seaweed of Saccharina japonica is the most abundantly cultured brown seaweed in the world, and has been consumed in the food industry due to its nutrition and the unique properties of its polysaccharides. In this study, fucoidan (LJNF3), purified from S. japonica, was found to be a novel sulfated galactofucan, with the monosaccharide of only fucose and galactose in a ratio of 79.22:20.78, and with an 11.36% content of sulfate groups. NMR spectroscopy showed that LJNF3 consists of (1→3)-α-l-fucopyranosyl-4-SO₃ residues and (1→6)-β-d-galactopyranose units. The molecular mechanism of the anti-inflammatory effect in RAW264.7 demonstrated that LJNF3 reduced the production of nitric oxide (NO), and down-regulated the expression of MAPK (including p38, ENK and JNK) and NF-κB (including p65 and IKKα/IKKβ) signaling pathways. In a zebrafish experiment assay, LJNF3 showed a significantly protective effect, by reducing the cell death rate, inhibiting NO to 59.43%, and decreasing about 40% of reactive oxygen species. This study indicated that LJNF3, which only consisted of fucose and galactose, had the potential to be developed in the biomedical, food and cosmetic industries.

Structure Differences of Water Soluble Polysaccharides in Astragalus membranaceus Induced by Origin and Their Bioactivity

Astragalus membranaceus is a functional food with multiple bioactivities. It presents differentiated health benefits due to origins. Polysaccharides (APS) are the leading bioactive macromolecules of A. membranaceus, which are highly related to its health benefits. However, the effect of origin on the structural characteristics of APSs remains unclear. In this work, polysaccharides from four origins were isolated and identified by NMR. The results showed APSs of four origins had identical monosaccharide composition and glycosidic linkage. Rhamnogalacturonan II pectins and α-(1→4)-glucan were the dominant polysaccharides. However, the level of methyl ester in pectins varied to a large extent. The molecular weight profiles of APSs were also different. Inner Mongolia APS had the largest percentage of 20-40 kDa polysaccharides. Molecular weight and methyl ester level were two important parameters determining the difference of APSs from four origins. These results were helpful to recognize the origin-related quality of A. membranaceus.

Reviews on mechanisms of in vitro antioxidant, antibacterial and anticancer activities of water-soluble plant polysaccharides

Degenerative diseases such as cancer and cardiovascular diseases, and antimicrobial resistance are becoming prominent health problems needing utmost public health attention. Curative interventions such as the use of pharmaceutical drugs and alternative plant medicines are increasingly being explored. Plant polysaccharides have gained attention for their promising bioactivities such as antioxidant, antimicrobial and anticancer activities. Bioactive plant polysaccharides are also being preferred for their relatively few side effects compared to conventional pharmaceuticals. The elucidation of the bioactive potential of plant polysaccharides in disease treatment entails an understanding of the factors that determine their biofunctional properties using functional and mechanistic assays. This review summarizes the literature on the composition, structural, functional, and mechanistic determinations of the antioxidant, anticancer and antimicrobial activities of plant polysaccharides. The outcome of this review highlights the leading trends in the elucidation of the antioxidant, anticancer and antimicrobial activities of plant polysaccharides and underscores the promising health benefits of plant polysaccharides.

Polysaccharides from Laminaria japonica: an insight into the current research on structural features and biological properties

Laminaria japonica, one of the most widespread seafood consumed in China and many other nations, has been traditionally utilized as an effective therapeutically active substance for treating weight loss, phlegm elimination, and detumescence for more than 2000 years. Numerous studies have found that the polysaccharides play an indispensable role in the nutritional and medicinal value of L. japonica. Water extraction and alcohol precipitation method is the most used method. Approximately 56 LJPs were successfully isolated and purified from L. japonica, whereas only few of them were well characterized. Modern pharmacological studies have shown that L. japonica polysaccharides (LJPs) have high-order structural features and multiple biological activities, including anti-tumor, anti-thrombotic, anti-atherosclerosis, hypolipidemic, hypoglycemic, antioxidant, anti-inflammatory, renoprotective, and immunomodulatory. In addition, the structural characteristics of LJPs are closely related to their biological activity. In this review, the extraction and purification methods, structural characteristics, biological activities, clinical settings, toxicities, and structure-activity relationships of LJPs are comprehensively summarized. The structural characteristics and biological activities as well as the underlying molecular mechanisms of LJPs were also outlined. Furthermore, the clinical settings and structure-activity functions of LJPs were highlighted. Some research perspectives and challenges in the study of LJPs were also proposed.

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.

Characterization of polysaccharides from Tetrastigma hemsleyanum Diels et Gilg Roots and their effects on antioxidant activity and H2O2-induced oxidative damage in RAW 264.7 cells

This work presents an investigation on the composition and structure of polysaccharides from the roots of Tetrastigma hemsleyanum (THP) and its associated antioxidant activity. It further explores the protective effect of THP on RAW264.7 cells against cytotoxicity induced by H₂O₂. Ion chromatography (IC) revealed that THP contained glucose, arabinose, mannose, glucuronic acid, galactose and galacturonic acid, in different molar ratios. Furthermore, gel permeation chromatography-refractive index-multiangle laser light scattering (GPC-RI-MALS) was employed to deduce the relative molecular mass (M_w) of the polysaccharide, which was 177.1 ± 1.8 kDa. Fourier transform infrared spectroscopy (FT-IR) and Congo red binding assay highlighted that the THP had a steady α-triple helix conformation. Similarly, assays of antioxidant activity disclosed that THP had reasonable concentration-dependent hydroxyl radical and superoxide radical scavenging activities, peroxidation inhibition ability and ferrous ion chelating potency, in addition to a significant 1,1-diphenyl-2-picrylhydrazyl radical scavenging capacity. Moreover, THP could protect RAW264.7 cells against H₂O₂-induced cytotoxicity by decreasing intracellular ROS levels, reducing catalase (CAT) and superoxide dismutase (SOD) activities, increasing lactate dehydrogenase (LDH) activity and increment in malondialdehyde (MDA) level. Data retrieved from the in vitro models explicitly established the antioxidant capability of polysaccharides from T. hemsleyanum root extracts.

Enhancing Effect of a Roasting Treatment on the Radical Scavenging Activity of a Marine Brown Alga Polysaccharide (Alginic acid)

We found an effective roasting method that enhances the effects on various radical scavenging activities of polysaccharide (alginic acid) derived from the marine brown alga Lessonia trabeculata. These enhancing effects were observed by a roasting treatment under relatively high temperature conditions (160ºC and 180ºC), which were measured by (i) a stable radical compound diphenylpicrylhydrazyl (DPPH), (ii) a hydroperoxide generating system of linoleic acid autooxidation, and (iii) an opsonized zymosan (Opz)-induced oxygen radical generating system in human blood neutrophils. Although a significant enhancing effect of the roasting treatment on the radical scavenging activity of the alginic acid itself was not detected under relatively low temperature conditions (100ºC and 130ºC), the roasting treatment of a mixture of alginic acid and several specific amino acids caused considerable radical scavenging activities under the same roasting conditions. When alginic acid was roasted at relatively high temperatures (160ºC or 180ºC), the mixture of the alginic acid and specific amino acids exhibited much higher radical scavenging activities than did the alginic acid alone. The significance of this finding is discussed from the viewpoint of healthy food science.

Galactofucan from Laminaria japonica is not degraded by the human digestive system but inhibits pancreatic lipase and modifies the intestinal microbiota

The effects of galactofucan from Laminaria japonica on the digestion and intestinal microbiota of human were investigated in the present study. Crude fraction of the sulfated polysaccharide from L. japonica (CF) and its molecular-weight homogeneous fraction (CGF-3) were prepared and characterized. In the simulated digestion model for the human saliva and gastrointestinal tract, no obvious changes in the molecular weight or the reducing sugar content of CGF-3 were observed, indicating CGF-3 is resistant to the human digestive system. Then CGF-3 did not affect the α-amylase activity while it dose-dependently inhibited the activity of pancreatic lipase partly depending on its sulfate groups. In the in vitro fermentation with the human fecal microbiota, CF did not change the total carbohydrate, reducing sugar and short chain fatty acids contents, which indicated CF was not utilized by the microbiota. However, the microbiota composition was modulated greatly by CF intervention. These findings shed a light on the better understanding of the impacts of dietary galactofucan on the digestion and intestinal microbiota.

A review for natural polysaccharides with anti-pulmonary fibrosis properties, which may benefit to patients infected by 2019-nCoV

Pulmonary fibrosis (PF) is a lung disease with highly heterogeneous and mortality rate, but its therapeutic options are now still limited. Corona virus disease 2019 (COVID-19) has been characterized by WHO as a pandemic, and the global number of confirmed COVID-19 cases has been more than 8.0 million. It is strongly supported for that PF should be one of the major complications in COVID-19 patients by the evidences of epidemiology, viral immunology and current clinical researches. The anti-PF properties of naturally occurring polysaccharides have attracted increasing attention in last two decades, but is still lack of a comprehensively understanding. In present review, the resources, structural features, anti-PF activities, and underlying mechanisms of these polysaccharides are summarized and analyzed, which was expected to provide a scientific evidence supporting the application of polysaccharides for preventing or treating PF in COVID-19 patients.

Screening active fractions from Pinus massoniana pollen for inhibiting ALV-J replication and their structure activity relationship investigation

The objective was to identify the active fractions of polysaccharide against replication of ALV-J and elucidate their structure activity relationship. The optimal extraction conditions were extracting temperature 90℃, pH 9 and the ratio of liquid to solid 30:1. Under these conditions, extraction yield of total polysaccharide was 6.5 % ± 0.19 %. Total polysaccharide was then purified by DEAE-52 cellulose and Sephadex G-200 gel. Three fractions, PPP-1, PPP-2, and PPP-3, were identified with molecular weight of 463.70, 99.41, and 26.97 kDa, respectively. Three polysaccharide fractions were all composed of 10 monosaccharides in different proportions. Compared with PPP-1, which was mainly composed of glucose, PPP-2 and PPP-3 contained a higher proportion of galactose, glucuronic acid and galacturonic acid. The Congo red assay indicated that the PPP-2 may have a triple helical structure, while PPP-1 and PPP-3 were absent. In vitro assay showed that there was no significant cytotoxicity among the polysaccharide fractions under the concentration of 800 μg mL^-1 (P > 0.05). The antiviral test showed that PPP-2 had the strongest activity, indicating PPP-2 was the major antiviral component. The structure-activity relationship showed that the antiviral activities of polysaccharide fractions were affected by their monosaccharide composition, molecular weight, and triple helical structure, which was a result of a combination of multiple molecular structural factors. These results showed that the PPP-2 could be exploited as a valued product for replacing synthetic antiviral drugs, and provided support for future applications of polysaccharide from Pinus massoniana pollen as a useful source for antiviral agent.

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.

Sulfation, structural analysis, and anticoagulant bioactivity of ginger polysaccharides

In this study, ginger polysaccharide (GP), ginger polysaccharide 1 (GP1), and ginger polysaccharide 2 (GP2) from ginger were firstly modified by sulfation. Fourier transform infrared, and nuclear magnetic resonance spectra investigation of sulfated ginger polysaccharide (SGP), sulfated ginger polysaccharide 1 (SGP1), and sulfated ginger polysaccharide 2 (SGP2) revealed that the sulfation successfully occurred with the characteristic absorption peak of polysaccharide. Congo red experiment showed that triple helical structure existed in SGP and SGP1, but random coils existed in SGP2. SGP, SGP1, and SGP2 all showed a rough and rugged surface with plenty of small pores. The blood clotting time of SGP2 or SGP at 2 mg/mL in activated partial thromboplastin time (APTT) assay was 41.42 or 38.01 s, respectively, which were approximately 1.33- and 1.22-fold longer than that of the physiological saline. Compared to the saline control group, prothrombin time (PT) was increased by 1.22-fold with the addition of GP at 2 mg/mL. However, no clotting inhibition phenomenon was observed in thrombin time test even at the concentrations that APTT and PT were obviously prolonged. It indicated that GP2, SGP2, and SGP inhibited the intrinsic pathway of coagulation, but GP inhibited both the intrinsic and extrinsic pathways of coagulation. Hence, ginger polysaccharides might be used as anticoagulants and therapeutic reagents for thrombosis.

Different extraction methods bring about distinct physicochemical properties and antioxidant activities of Sargassum fusiforme fucoidans

Fucoidan is a complex sulfated polysaccharide and an active component found in the cell wall of brown seaweeds. In the present study, fucoidans were obtained from Sargassum fusiforme using different extraction methods, including hot water (prepared fucoidan was named as WSFF), dilute hydrochloric acid (ASFF), and calcium chloride solution (CSFF). The assessments were performed on S. fusiforme fucoidans based on their chemical composition, molecular conformations, and in vitro antioxidant activities. ASFF showed the maximum extraction yield (11.24%), whereas CSFF exhibited the minimum yield (3.94%). The monosaccharide composition of WSFF, ASFF, and CSFF was similar, but the molar ratio of monosaccharide was quite different. Moreover, their molecular weight, Fourier transform infrared (FT-IR) spectrum, surface morphology, uronic acid content and degree of sulfation were distinct. The Congo red test and Circular dichroism spectroscopy analysis displayed some differences in solution conformation of these samples. Furthermore, WSFF, ASFF, and CSFF showed distinct in vitro antioxidant activities evaluated by DPPH and hydroxyl radical scavenging assays. The present study provides scientific evidence on the influences of extraction methods on the physicochemical characteristics, conformation behaviors and antioxidant activities of S. fusiforme fucoidans.

Structural Characterization and α-Glucosidase Inhibitory and Antioxidant Activities of Fucoidans Extracted from Saccharina japonica

Two sulfated fucoidan fractions (Lj3 and Lj5) were extracted from Saccharina japonica and then subjected to acid hydrolysis to obtain Lj3h and Lj5h. Lj3h and Lj5h were characterized using IR, methylation analysis, and mass spectrometry. It was found that Lj3h and Lj5h were homogeneous low molecular weight fucoidans. Specifically, Lj3h was composed of the main chain of 1,3-linked α-L-fucopyranose residues with sulfate at C-2 and/or C-4 and three different monosaccharides (galactose, glucose, mannose) branched at C-2 and/or C-4 of fucose residue. Lj5h contained backbones of alternating galactopyranose residues and fucopyranose residues attached via a 1→3 linkage (galactofucan) and 1→6 linked galactan. The sulfation pattern was mainly located at C2/C4 fucose or galactose residues and more branches occupied at C-4 of fucose residue and C-2, C-3 or/and C-6 of galactose residue. In vitro assay indicated that, among the four fucoidans tested, only Lj5 showed potent α-glucosidase inhibitory activity with IC50 of 153.27±22.89 μg/mL, and the two parent fucoidans, Lj3 and Lj5, showed better antioxidant activity than their derivatives. These findings highlight the structure and bioactivity diversity of Saccharina japonica-derived fucoidans.

Response surface methodology for the fermentation of polysaccharides from Auricularia auricula using Trichoderma viride and their antioxidant activities

Fermentation technology was used to improve the antioxidant activities of Auricularia auricula polysaccharide (AAP). Response surface methodology (RSM) was used to optimize the fermentation conditions. The effects of 4 independent factors: water content (X₁: 40-80%), inoculation amount (X₂: 2-20%), temperature (X₃: 24-32 °C), and time (X₄: 4-6 d) on the biological degradation efficiency were evaluated. The RSM results showed that the optimal fermentation conditions were: X₁: 61.7%, X₂: 12.4%, X₃: 31.0 °C, X₄: 5.5 d. Verification tests showed no significant differences between the practical and the predictive values for each response. Under the optimal conditions, the degradation rate was 26.89 ± 0.14%, without significant differences with the predicted value (27.03%). The degradation products were classified to different molecular weight (M_w) polysaccharide fragments using membrane separation technology. The FT-IR analysis and monosaccharide composition analysis of degraded AAP (D-AAP-VI) showed that D-AAP-VI was a furan type polysaccharide, which was different from the total AAP (pyran type). In addition, compared to total AAP, the antioxidant activities in vitro of D-AAP-VI were significantly improved (p < 0.05) and D-AAP-VI showed the strongest antioxidant activity. These results indicated that biological degradation may be a suitable way to improve the antioxidant activities of natural polysaccharides.

Optimizing the Extraction of Polysaccharides from Bletilla ochracea Schltr. Using Response Surface Methodology (RSM) and Evaluating their Antioxidant Activity

Bletilla ochracea Schltr. polysaccharides (BOP) have a similar structure to Bletilla striata (Thunb.) Reichb.f. (Orchidaceae) polysaccharides (BSP). Therefore, BOP can be considered as a substitute for BSP in the food, pharmaceuticals and cosmetics fields. To the best of our knowledge, little information is available regarding the optimization of extraction and antioxidant activity of BOP. In this study, response surface methodology (RSM) was firstly used for optimizing the extraction parameters of BOP. The results suggested that the optimal conditions included a temperature of 82 °C, a duration of 85 min and a liquid/material ratio of 30 mL/g. In these conditions, we received 26.45% ± 0.18% as the experimental yield. In addition, BOP exhibited strong concentration-dependent antioxidant abilities in vitro. The half-maximal effective concentration (EC50) values of BOP against 1,1-diphenyl-2-picrylhydrazyl (DPPH·), 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonate) (ABTS+·), hydroxyl (·OH) and superoxide anion (·O2−) radicals and ferrous ions (Fe2+) were determined as 692.16, 224.09, 542.22, 600.53 and 515.70 µg/mL, respectively. In conclusion, our results indicate that BOP can be a potential natural antioxidant, deserving further investigation.

The Antioxidant Activity of Polysaccharides Derived from Marine Organisms: An Overview

Marine-derived antioxidant polysaccharides have aroused extensive attention because of their potential nutritional and therapeutic benefits. However, the comprehensive comparison of identified marine-derived antioxidant polysaccharides is still inaccessible, which would facilitate the discovery of more efficient antioxidants from marine organisms. Thus, this review summarizes the sources, chemical composition, structural characteristics, and antioxidant capacity of marine antioxidant polysaccharides, as well as their protective in vivo effects mediated by antioxidative stress reported in the last few years (2013-2019), and especially highlights the dominant role of marine algae as antioxidant polysaccharide source. In addition, the relationships between the chemical composition and structural characteristics of marine antioxidant polysaccharides with their antioxidant capacity were also discussed. The antioxidant activity was found to be determined by multiple factors, including molecular weight, monosaccharide composition, sulfate position and its degree.