Fabrication of Algal Polysaccharides-Based Nanoparticles and Evaluation of Their Antioxidant and Anti-Inflammatory Potential

Molecular weight distribution and functional group profiles of TEMPO-oxidized lyocell fibers

BackgroundJujube resources are abundant in China, and Shanxi Province in particular is one of the places where they originated. The most famous 6 geographical indication (GI) jujube species in Shanxi are often masqueraded by nonoriginal jujube species, which seriously undermines the brand image. However, the current national quality standards, which have simple indicators, cannot completely trace the botanical and geographical origin of GI jujubes. Compared with small biomolecules and genes, polysaccharides possess a complicated structure and are sensitive to their geographical location and botanical origin, and these characteristics are important for botanical and geographical traceability. Therefore, we selected the 6 most famous GI jujube species in Shanxi Province, measured and analyzed their crude polysaccharide characterizations, and then selected efficient tracing indicators.ResultsThe crude polysaccharides from 6 GI jujube species of Shanxi Province were tested with several parameters, including their purity (the content of polysaccharides), uronic acid content, Mw distribution, monosaccharide composition, functional groups and bonds. In the assays that measured purity and uronic acid content, the purity varied within a very narrow band (96–99%) and presented no negative or positive correlation with uronic acid content. In the experiment that measured the Mw distribution by HPGPC, five peaks (RT1, RT2, RT3, RT4, RT5) were almost observed in 6 jujube species, and the RT3 content (240–250 Da), which showed a significant correlation to the content of RT4 and RT5, exhibited significant differences among 6 jujube species (RSD = 1.28 > 1.00). The monosaccharide composition indicated that the polysaccharides from 6 jujube species were rich in glucose (55–75%), arabinose (10–15%) and galactose acid (10–20%), with small amounts of rhamnose, glucosamine hydrochloride, galactose, xylose, and mannose (less than 5%). The FT-IR spectrum showed that crude polysaccharides from six jujube species shared similar functional groups and chemical bonds.ConclusionsThe results above indicated that in the 6 GI jujube species, both homogeneity and differences were observed in the Mw distribution of crude polysaccharides. First, five peaks (RT1, RT2, RT3, RT4, RT5), which represent the Mw of 186,646–285,262 Da (RT1), 4634–17,296 Da (RT2), 240–250 Da (RT3), 98–103 Da (RT4) and 57–64 Da (RT5), respectively, could be detected in all 6 jujube species. Second, the RT3 contents exhibited significant differences among the 6 jujube species (RSD = 1.28 > 1.00) and showed a significant correlation with RT4 and RT5. Therefore, the Mw distribution may be treated as a potential distinguishing indicator among the 6 jujube species.Graphical

Antiallergic activities of polysaccharides derived from Coptis chinensis.

The content and composition of fucoidan in six brown macroalgae were investigated. The influence of different washing steps and two types of extraction methods on the yield and composition of fucoidan were assessed. The composition of the extract was determined by using a colorimetric method to measure the total sugar, sulfate, and protein contents of the fucoidan. The monosaccharide composition was assessed using high-performance liquid chromatography. The structures of the algal polysaccharide were studied using Fourier transform infrared-attenuated total reflectance spectroscopy. The fucoidan content extracted using method I was 13.13% (of dry weight), 24.00%, and 22.67% from Sargassum glaucescens, Sargassum horneri, and Laminaria japonica, respectively. By contrast, the fucoidan content extracted using method II was 4.20%, 4.80%, and 4.64% from S. glaucescens, S. horneri, and L. japonica, respectively. The samples extracted using method II were lower in total sugar content but higher in sulfated content than those extracted using method I. Using method II yielded the highest fucose content in S. glaucescens (20.89%) and Hizikia fusiformis (15.89%). The proportion of H. fusiformis was lower than that of S. glaucescens because the biomass of the H. fusiformis was much larger in the wild. Therefore, we consider H. fusiformis to be a rich source of fucoidan for human consumption.

Comparison of physicochemical properties and antidiabetic effects of polysaccharides extracted from three seaweed species

Cordyceps cicadae is a medicinal fungus popularly used in traditional Chinese medicine for treating cancer, asthma, and kidney diseases. In this study, crude polysaccharides (CP) and water-soluble nondigestible polysaccharides (NDPs) were prepared from the fruiting bodies of cultivated C. cicadae, and their physicochemical properties and anti-inflammatory activity in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages were examined. The results showed yields of CP and NDP of 3.42% and 1.17%, respectively. CP and NDP showed a similar monosaccharide composition, of which the predominant monosaccharide was mannose, followed by galactose and glucose. Differences in molecular weight distribution between CP and NDP were apparent; CP possessed two major (3.1 kDa and 21.5 kDa) and one minor (678.2 kDa) macromolecular populations, whereas NDP contained only one macromolecular population (24.4 kDa). Furthermore, CP but not NDP had a triple helix conformation. The bioassay results showed that, although both CP and NDP possess anti-inflammatory activity, NDP had stronger inhibitory effects on nitric oxide, IL-1β, and TNF-α production in LPS-stimulated RAW264.7 macrophages. From this study, we conclude that the differences in conformation and molecular weight distribution between CP and NDP may contribute to their differences in anti-inflammatory activity.

Marine algae are interesting as a plentiful source of many bioactive compounds, including polysaccharides, which represent various structurally different polymers of high diversity in monosaccharide composition, absolute and anomeric configuration, glycosidic linkages, molecular mass, and the presence and distribution of various functional groups. These polysaccharides are used by algae as cell wall structural components or food reserve. Algal polysaccharides are highly indicative for main algal taxa. Sulfated galactans of periodical unit/linkage sequence (agars, carrageenans) are typical for red algae, alginates, and fucoidans for brown algae; sulfated glucuronoxylorhamnans (ulvans) and other sulphated glycans for green algae. Algal cell wall polysaccharides are extracted from the raw material and further purified by preparative chromatography and/or chemical treatment. Many algal polysaccharides are assigned as phycocolloids due to their good solubility in water and their ability to create colloid systems, including gels and films. They also demonstrate various biological activities (immunomodulation, antitumor, anticoagulant, antiviral, and many other activities), which are prerequisites of pharmaceutical and medicinal applications. Finally, initially inactive or weakly active natural algal polysaccharides can be partially degraded or structurally modified to be fitted to various medicinal applications.

The endocarp of Exocarpium Citri Grandis (ECG) is abundant in various bioactive components, such as polysaccharides; however, there are few studies on them. Thus, it is highly necessary to carry out further research on the structural characterization and biological activities of ECG polysaccharides (EPs), which are important bioactive substances. In this study, water-extracted EPs were precipitated by ethanol with final concentrations of 50%, 70%, and 90% (v/v), respectively. Three crude polysaccharides (EP50, EP70, and EP90) were fractioned successively. The three polysaccharide fractions were structurally elucidated and were investigated in vitro for their biological activities related to glucose metabolism containing inhibitory effects on α-glucosidase and non-enzymatic glycosylation and their antioxidant capacities. The main results are summarized as follows: (1) Gradient ethanol precipitation and physicochemical properties of EPs: The yields of EP50, EP70, and EP90 were 11.18%, 0.57%, and 0.18%, respectively. The total sugar contents were 40.01%, 52.61%, and 53.46%, and the uronic acid contents were 30.25%, 18.11%, and 8.17%, respectively. In addition, the three fractions had the same composition of monosaccharides, including rhamnose, arabinose, galactose, glucose, xylose, mannose, galacturonic acid, and glucuronic acid, with differences in the content of neutral and acidic monosaccharides. They all may be branched polymers and spherical conformation, and they were acidic polysaccharides containing esterified and non-esterified uronic acids, pyranose-form sugars, and glycosidic linkages of α-configuration and β-configuration, with esterification degrees of 32.25%, 28.82%, and 15.58%, respectively. Meanwhile, EP50, EP70, and EP90 were mainly amorphous, and the molecular conformation in solution was a spherical branching polymer without a triple helix structure. The EPs exhibited excellent thermal stability, with their structures remaining stable below 170 °C. (2) In terms of activity research, the results showed that EPs had a good α-glucosidase inhibitory effect with IC50 values of 1.17 mg/mL, 1.40 mg/mL, and 2.72 mg/mL, respectively, among which EP50 was the best. EP50, EP70, and EP90 displayed antioxidant activity by scavenging DPPH and ABTS radicals as well as oxygen radical absorbance capacity. Among them, EP90 had the strongest antioxidant activity. Furthermore, the EPs showed prominent effects on the inhibitory activity of non-enzymatic glycosylation. In summary, the research on the extraction of polysaccharide from ECG provides a technical reference for the further utilization of ECG resources. This study on antioxidant activity provides theoretical support for their use as a natural antioxidant. As oxidation and glycation are relevant to diabetic complications, the result of this work suggests that EPs may be effective in preventing and treating diabetic complications.

SummaryThe effects of thermal treatment on the changes in the colour, the molecular weight distribution, amino acid profiles and the overall antioxidant activities of loach peptide were investigated. When the thermal temperature was rising, the browning was enhanced. The contents of free amino acids Gly, Arg, Thr and Tyr were increased, whereas those of Asp, Ser, Met, Cys, Trp and Lys were decreased. The scavenging activities (1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging activity, the oxygen radical absorbance capacity (ORAC) and the reducing power of loach peptides after different thermal treatments were lower than those of the control, whereas the Cu2+ chelating activity was higher (except from the sample treated at 100 °C, 20 min). The heat treatment at 121 °C, 15 min was shown to be the best thermal processing, as it caused the least loss in radical scavenging activity and showed relatively higher Cu2+ chelating activity.

Characterization of water and alkali-soluble polysaccharides from Pleurotus tuber-regium sclerotia

Ginseng polysaccharides (GPs) have shown gut microbiota-related antitumor effects. However, the relation between their structures and antitumor functions remains unknown. Here, crude polysaccharide (GP-c) and its fractions neutral polysaccharide (GP-n) and pectin (GP-a) were prepared for structure characterization and anti-B16F10 melanoma effect evaluation, and their influence on gut microbiota diversities and short-chain fatty acids (SCFAs) were also analyzed. Spearman correlations among the altered gut microbiota, SCFAs, and antitumor effects were conducted to elucidate the structure-function relationships. It was shown that the structures of GP-c, GP-n, and GP-a varied in monosaccharide composition and molecular weight distribution. GP-n and GP-c showed anti-melanoma effects, whereas GP-a promoted its growth slightly. GP-n and GP-c restored SCFAs levels such as acetic acid and butyric acid; moreover, it improved the gut microbiota ecosystem by upregulating the abundance of Allobaculum and Bifidobacterium. However, the restoration effect of GP-a was weak, or even worse. In addition, these two bacteria were negatively correlated with the tumor weight and related with the altered SCFAs. In conclusion, GP-n is essential for the anti-melanoma effects of GP, and the potential mechanisms might be related with its specific regulation of Allobaculum and Bifidobacterium abundance, and tumor-associated SCFAs levels. The outcomes highlighted here enable a deeper insight into the structure-function relationship of GP and propose new opinions on its antitumor effect.

Acidic polysaccharide, which has various biological activities, is one of the most important components of sea cucumber. In the present study, crude polysaccharide was extracted from four species of sea cucumber from three different geographical zones, Pearsonothuria graeffei (Pg) from Indo-Pacific, Holothuria vagabunda (Hv) from Norwegian Coast, Stichopus tremulu (St) from Western Indian Ocean, and Isostichopus badionotu (Ib) from Western Atlantic. The polysaccharide extract was separated and purified with a cellulose DEAE anion-exchange column to obtain corresponding sea cucumber fucans (SC-Fucs). The chemical property of these SC-Fucs, including molecular weight, monosaccharide composition and sulfate content, was determined. Their structure was compared simply with fourier infrared spectrum analyzer and identified with high temperature 1H nuclear magnetic resonance spectrum analyzer (NMR) and room temperature 13C NMR. The results indicated that Fuc-Pg obtained from the torrid zone mainly contained 2,4-O-disulfated and non-sulfated fucose residue, whereas Fuc-Ib from the temperate zone contained non-, 2-O- and 2,4-O-disulfated fucose residue; Fuc-St from the frigid zone and Fuc-Hv from the torrid zone contained mainly non-sulfated fucose residue. The proton of SC-Fucs was better resolved via high temperature 1H NMR than via room temperature 1H NMR. The fingerprint of sea cucumber in different sea regions was established based on the index of anomer hydrogen signal in SC-Fucs. Further work will help to understand whether there exists a close relationship between the geographical area of sea cucumber and the sulfation pattern of SC-Fucs.

Microwave-assisted extraction, chemical characterization of polysaccharides from Lilium davidii var. unicolor Salisb and its antioxidant activities evaluation

Biological activities of sulfated polysaccharides from tropical seaweeds

Polysaccharides from hemp seeds exhibit antioxidant activities in vitro and in vivo. However, crude polysaccharide quality is often low owing to the presence of fibres and pigment impurities, which are difficult to eliminate in the hemp seed shell. In this study, crude polysaccharides from hemp kernels (HKP) were obtained by hot water extraction and separated by membrane ultrafiltration into eight fractions with different molecular weights. Total antioxidant capacity and free radical scavenging (DPPH) assays were performed to evaluate the antioxidant activities of HKP and the fractions in vitro. The structural characteristics of HKP were determined using various analytical techniques. The Fe3+-reducing power of HKP was 7.65 ± 0.22 μmol/g, and HKP possessed the highest DPPH radical-scavenging rates (94.30 ± 2.27%), similar to 5 mg/mL Vitamin C (Vc), which had a rate of 95%. The HKP was an acidic polysaccharide with a low molecular weight (4.21 ± 0.12 kDa). The monosaccharide composition indicated that HKP primarily comprised mannose, ribose, glucuronic acid, galacturonic acid, glucose, galactose, arabinose, and fucose in a molar ratio of 0.96:1.95:8.27:0.98:9.46:1.69:6.10:2.82. The molar mass of HKP was distributed widely in a triple helical conformation. This study provides a scientific basis for further research on the use of hemp polysaccharides.