Degradation of sulfated polysaccharides from Enteromorpha prolifera and their antioxidant activities

Structural characterization and anti-lung cancer activity of a sulfated glucurono-xylo-rhamnan from Enteromorpha prolifera

A sulfated glucurono-xylo-rhamnan (EP-3-H) was purified from a green alga, Enteromorpha prolifera. EP-3-H and its oligomers were characterized by high performance liquid chromatography, mass spectrometry and one and two-dimensional nuclear magnetic resource spectroscopy. The structural analysis showed EP-3-H has a backbone of glucurono-xylo-rhamnan, branches with glucuronic acid and sulfated at C3 of rhamnose and/or C2 of xylose. The inhibition of EP-3-H on human lung cancer A549 cell proliferation in vitro and its therapeutic effects in BALB/c-nu mice in vivo were determined to evaluate the anti-lung cancer activity of EP-3-H. The tumor inhibition level was 59 %, suggesting that EP-3-H might be a good candidate for the treatment of lung cancer. Surface plasmon resonance (SPR) studies revealed the IC₅₀ on the binding of fibroblast growth factors, (FGF1 and FGF2), to heparin were 0.85 and 1.47 mg/mL, respectively. These results suggest that EP-3-H inhibits cancer proliferation by interacting with these growth factors.

Aging - Oxidative stress, antioxidants and computational modeling

Aging is a degenerative, biological, time-dependent, universally conserved process thus designed as one of the highest known risk factors for morbidity and mortality. Every individual has its own aging mechanisms as both environmental conditions (75%) and genetics (25%) account for aging. Several theories have been proposed until now but not even a single theory solves this mystery. There are still some queries un-answered to the scientific community regarding mechanisms behind aging. However, oxidative stress theory (OST) is considered one of the famous theories that sees mitochondria as one of the leading organelles which largely contribute to the aging process. Many reactive oxygen species (ROS) are produced endogenously and exogenously that are associated with aging. But the mitochondrial ROS contribute largely to the aging process as mitochondrial dysfunction due to oxidative stress is considered one of the contributors toward aging. Although ROS is known to damage cell machinery, new evidence suggests their role in signal transduction to regulate biological and physiological processes. Moreover, besides mitochondria, other important cell organelles such as peroxisome and endoplasmic reticulum also produce ROS that contribute to aging. However, nature has provided humans with free radical scavengers called antioxidants that protect from harmful effects of ROS. Future predictions regarding aging, biochemical mechanisms involved, biomarkers internal and external factors can be easily done with machine learning algorithms and other computational models. This review explains important aspects of aging, the contribution of ROS producing organelles in aging, importance of antioxidants fighting against ROS, different computational models developed to understand the complexities of the aging.

Improved antioxidant and immunomodulatory activities of enzymatically degraded Porphyra haitanensis polysaccharides

Porphyra haitanensis polysaccharide (CPH) was degraded by pectinase to improve its biological activities. Box-Behnken response surface design was used to optimize the hydrolysis conditions. The molecular weight of CPH and the degraded P. haitanensis polysaccharide (DCPH) were measured to be 524 and 217 kDa, respectively. GC-MS spectrometry results showed that CPH and DCPH were mainly composed of galactose. In vitro antioxidant assays indicated that DCPH possessed improved radical scavenging activity and ferric iron reducing power when compared to those of CPH. In H₂ O₂ -treated RAW264.7 cells, DCPH was also found to be more effective in reducing the generation of malondialdehyde and reactive oxygen species than CPH. The immunomodulatory assays demonstrated that DCPH possessed superior activities in enhancing the proliferation, phagocytosis, and NO secretion in a RAW264.7 macrophage cell model to those of CPH. PRACTICAL APPLICATIONS: Polysaccharide is the most abundant bioactive component of an edible red algae Porphyra haitanensis. However, the use of CPH is limited due to its relatively low biological activities. Thus, in order to fully utilize P. haitanensis, it is necessary to enhance the biological activities of CPH for its practical use. An efficient and practical method to enhance the bioactivities of P. haitanensis polysaccharide has been developed in the present work. The DCPH prepared in this work could have potential applications in food and medicinal areas.

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.

Effects of dietary Enteromorpha powder supplementation on productive performance, egg quality, and antioxidant performance during the late laying period in Zi geese

This study investigated the effects of dietary Enteromorpha powder supplementation on the productive performance, egg quality, and antioxidant performance of Zi geese during the late laying period. Three hundred twelve Zi geese (1 yr old) were randomly allocated into 2 cohorts to form a control group and an experimental group (with each cohort including 6 replicates and 21 female geese and 5 male geese in each replicate). The control group was fed a basal diet, and the experimental group was fed a diet containing 3% Enteromorpha powder. The data showed that Enteromorpha powder supplementation significantly improved egg production, laying rate, average daily egg weight (P < 0.01), and egg yolk color (P < 0.05). Supplementation decreased the ADFI and feed conversion rate (P < 0.01). Compared with the control group, glutathione peroxidase (GSH-Px) activity was significantly higher in serum and ovary tissue (P < 0.05), but GSH-Px activity was lower in liver tissue (P < 0.01). Malondialdehyde was reduced in liver and ovary tissue (P < 0.05) in the Enteromorpha powder supplementation group. Meanwhile, the expression of the CAT gene was significantly upregulated in the liver (P < 0.01) in the Enteromorpha group. These results indicate that dietary Enteromorpha powder supplementation improved productive performance and reduced the level of lipid peroxidation in Zi geese during the late laying period.

Biochemical characterization and structural analysis of ulvan lyase from marine Alteromonas sp. reveals the basis for its salt tolerance

Marine macroalgae have gained considerable attention as renewable biomass sources. Ulvan is a water-soluble anionic polysaccharide, and its depolymerization into fermentable monosaccharides has great potential for the production of bioethanol or high-value food additives. Ulvan lyase from Alteromonas sp. (AsPL) utilizes a β-elimination mechanism to cleave the glycosidic bond between rhamnose 3-sulfate and glucuronic acid, forming an unsaturated uronic acid at the non-reducing end. AsPL was active in the temperature range of 30-50 °C and pH values ranging from 7.5 to 9.5. Furthermore, AsPL was found to be halophilic, showing high activity and stability in the presence of up to 2.5 M NaCl. The apparent K_m and k_cat values of AsPL are 3.19 ± 0.37 mg mL^-1 and 4.19 ± 0.21 s^-1, respectively. Crystal structure analysis revealed that AsPL adopts a β-propeller fold with four anti-parallel β-strands in each of the seven propeller blades. The acid residues at the protein surface and two Ca²⁺ coordination sites contribute to its salt tolerance. The research on ulvan lyase has potential commercial value in the utilization of algal resources for biofuel production to relieve the environmental burden of petrochemicals.

Anti-ageing and antioxidant effects of sulfate oligosaccharides from green algae Ulva lactuca and Enteromorpha prolifera in SAMP8 mice

Oligosaccharides from green algae Ulva lactuca (ULO) and Enteromorpha prolifera (EPO) were used for investigation of anti-ageing effects and the underlying mechanism in SAMP8 mice. The structural properties of ULO and EPO were analyzed by fourier-transform infrared spectroscopy, gas chromatography-mass spectrometry, and agarose gel electrophoresis. These oligosaccharides enhanced the glutathione, superoxide dismutase, catalase, and telomerase levels and total antioxidant capicity, and decreased the levels of malondialdehyde and advanced glycation end products. After ULO and EPO treatment, the levels of inflammatory factors, including IFN-γ, TNF-α, and IL-6, decreased; the BDNF and ChAT levels increased; and hippocampal neurons were protected. Downregulation of the p53 and FOXO1 genes and upregulation of the Sirt1 gene indicated that ULO and EPO have potential therapeutic effects in the prevention of ageing in SAMP8 mice. By 16S rRNA gene high-throughput sequencing, the abundance of Desulfovibrio was discovered to be markedly different in mice treated with ULO and EPO. The abundances of Verrucomicrobiaceae, Odoribacteraceae, Mogibacteriaceae, Planococcaceae, and Coriobacteriaceae were positively correlated with age-related indicators. These results demonstrated that oligosaccharides from U. lactuca and E. prolifera are ideal candidate compounds that can be used in functional foods and pharmaceuticals to prevent ageing.

Repair Effects of Astragalus Polysaccharides with Different Molecular Weights on Oxidatively Damaged HK-2 Cells

This study investigated the repair effects of three Astragalus polysaccharides (APSs) with different molecular weights (Mws) on injured human renal proximal tubular epithelial (HK-2) cells to reveal the effect of Mw of polysaccharide on cell repair. A damage model was established by injuring HK-2 cells with 2.6 mM oxalate, and APS0, APS1, and APS2 with Mw of 11.03, 4.72, and 2.61 KDa were used to repair the damaged cells. After repair by APSs, the morphology of damaged HK-2 cells gradually returned to normal, the destruction of intercellular junctions recovered, intracellular reactive oxygen species production amount decreased, and their mitochondrial membrane potential increased. In addition, the cell cycle progression gradually normalized, lysosome integrity increased, and cell apoptotic rates obviously declined in the repaired cells. All three APSs could promote the expression of Keap1, Nrf2, SOD1, and CAT. In addition, the expression levels of inflammation markers containing MCP-1 and IL-6 decreased after APS repair. We deduced that APSs exert their repair function by activating the Nrf2-Keap1 signaling pathway and inhibiting inflammation. Among the APSs, APS1 with a moderate Mw provided the strongest repair effect. APSs may have a preventive effect on kidney stones.

Polysaccharides from Enteromorpha Prolifera Ameliorate Acute Myocardial Infarction in Vitro and in Vivo via Up-Regulating HIF-1α

Acute myocardial infarction (AMI) is a serious heart disease and the main reason for heart failure and sudden death worldwide. This study investigated the effects of polysaccharides from Enteromorpha prolifera (PEP) on AMI in vitro and in vivo, as well as the underlying mechanisms.Human cardiac microvascular endothelial cells (HCMVEC) were cultured in vitro in an oxygen-glucose deprivation (OGD) environment to induce injury. The viability and apoptosis of HCMVEC were then detected using CCK-8 assay and Annexin V-FITC/PI staining, respectively. ELISA was performed to measure the concentrations of inflammatory cytokines. Cell transfection was conducted to reduce the expression of HIF-1α. Expression of key factors involving in cell proliferation, apoptosis, autophagy, MEK/ERK, and the NF-κB and mTOR pathways were evaluated using Western blotting. In vivo, Wistar rats were pre-treated by PEP and AMI was induced. The infarct size and cardiac functions (LVEDD, LVEF and LVFS) were measured.In vitro, PEP treatment significantly protected HCMVEC from OGD-induced viability loss, proliferation inhibition, apoptosis, inflammatory cytokine expression, and autophagy. Moreover, PEP enhanced the expression of HIF-1α in HCMVEC via the MEK/ERK pathway. HIF-1α participated in the protective effects of PEP on OGD-treated HCMVEC. Furthermore, PEP attenuated OGD-induced NF-κB pathway activation and promoted the mTOR pathway in HCMVEC. In vivo, PEP pre-treatment reduced the infarct size and enhanced the LVEDD, LVEF and LVFS of rats via up-regulation of HIF-1α.PEP ameliorated AMI in vitro and in vivo through up-regulation of HIF-1α. In vitro, PEP could activate the MEK/ERK and mTOR pathways, but inactivate the NF-κB pathway in OGD-treated HCMVEC.

Enzymatic hydrolysates obtained from Trametes versicolor polysaccharopeptides protect human skin keratinocyte against AAPH-induced oxidative stress and inflammatory

BACKGROUND

Polysaccharopeptides (PSPs) extracted from Trametes versicolor show antitumor, anti-inflammatory, and immunomodulation effects. According to our previous report, the enzymatic hydrolysates obtained from T versicolor PSPs by 80 U/mL β-1,3-D-glucanase (PSPs-EH80) did not change the functional groups of PSPs but enhanced their antioxidative activities. However, the mechanism elevating the antioxidant and anti-inflammatory effect of PSPs-EH80 is not clear.

AIMS

This research focused on the protective mechanism(s) of PSPs-EH80 against free radical and 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH)-induced oxidative damage in human keratinocyte (HaCaT) cells.

METHODS

We evaluated the anti-inflammatory potential of PSPs-EH80 by assessing its free radical-induced oxidative damage. Using the HaCaT cell as the experimental system, we tested the protective effects of PSPs-EH80 on a model of AAPH-induced cellular oxidative damage through the assessment of cell survival rate. Heme oxygenase 1 (HO-1), nuclear factor erythroid 2-related factor 2 (Nrf2), cyclooxygenase-2 (COX-2), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase were determined using MTT assays and Western blotting.

RESULTS

We demonstrated that PSPs-EH80 significantly enhanced keratinocyte viability, and augmented the antioxidant HO-1 expressions through upregulation of the Nrf2, compared with PSPs. Furthermore, PSPs-EH80 significantly reduced AAPH-induced COX-2 expressions through downregulation of the ERK, p38, and NF-κB signaling pathways.

CONCLUSION

The PSPs-EH80 exhibits a stronger antioxidant and anti-inflammatory capacity than PSPs. Therefore, PSPs-EH80 could be effective for attenuating free radical-induced oxidative damage in human skin and can be applied widely in the fields of cosmetics and medicine.

Partial Characterization, the Immune Modulation and Anticancer Activities of Sulfated Polysaccharides from Filamentous Microalgae Tribonema sp

Recently, Tribonema sp., a kind of filamentous microalgae, has been studied for biofuel production due to its accumulation of triacylglycerols. However, the polysaccharides of Tribonema sp. and their biological activities have rarely been reported. In this paper, we extracted sulfated polysaccharides from Tribonema sp. (TSP), characterized their chemical composition and structure, and determined their immunostimulation and anticancer activities on RAW264.7 macrophage cells and HepG2 cells. The results showed that TSP is a sulfated polysaccharide with a M_w of 197 kDa. TSP is a heteropolysaccharide that is composed mainly of galactose. It showed significant immune-modulatory activity by stimulating macrophage cells, such as upregulating interleukin 6 (IL-6), interleukin 10 (IL-10), and tumor necrosis factor α (TNF-α). In addition, TSP also showed significant dose-dependent anticancer activity (with an inhibition rate of up to 66.8% at 250 µg/mL) on HepG2 cells as determined by the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The cycle analysis indicated that the anticancer activity of TSP is mainly the result of induced cell apoptosis rather than affecting the cell cycle and mitosis of HepG2 cells. These findings suggest that TSP might have potential as an anticancer resource, but further research is needed, especially in vivo experiments, to explore the anticancer mechanism of TSP.

Structure characterization of low molecular weight sulfate Ulva polysaccharide and the effect of its derivative on iron deficiency anemia

Sulfate Ulva polysaccharide with low molecular weight was prepared by enzymatic method and name SUE. The structural characterization of SUE and the effect of its derivative SUE-iron (III) on iron deficiency anemia were studied. Results showed SUE with molecular weight of 178 kDa were consisted of 57.9% rhamnose, 12.1% glucose, 16.3% glucuronic acid, and 13.7% xylose. The backbone contained (1 → 3, 4)-linked rhamnose, (1 → 4)-linked xylose, (1 → 6)-linked glucose and sulfate substitution was at C-3 of rhamnose. Due to high contents of sulfate group (23.7 ± 1.1%) and uronic acid, SUE-iron (III) with 20.3% iron content was synthesized. In order to evaluate the effects of SUE-iron (III) supplementation, an IDA animal model was created. After iron supplement administration, the SUE‑iron (III) showed effective effect on returning hemoglobin, red blood cells, serum iron, and erythropoietin to the normal levels. The hematological index of rats showed no difference from that in positive group. Besides, SUE-iron (III) is beneficial to alleviate inflammatory damage caused by IDA. These suggest that SUE-iron (III) might be exploited as safe and effective new iron supplement.

Enteromorpha prolifera oligomers relieve pancreatic injury in streptozotocin (STZ)-induced diabetic mice

The polysaccharides of Enteromorpha prolifera (PEP) displayed various bioactivities such as anti-viral, anti-inflammatory and immune-regulative effects. However, no studies were performed on the biological effect of Enteromorpha prolifera oligomers (EPO). In this study, we prepared EPO and evaluated their anti-diabetic effect. By enzymatic degradation, EPO were produced from PEP, and the average molecular weight was identified to be 44.1 kDa by Gel Permeation Chromatography (GPC) analysis. The major monosaccharide units of EPO were measured to be rhamnose, glucuronic acid, glucose, xylose and galactose by capillary electrophoresis assay. Based on the in vitro studies, EPO presented potent reducing power and antioxidant effect such as the scavenging of 1, 1-diphenyl-2-picrylhydrazyl (DPPH), superoxide and NO radicals. The in vivo studies show that EPO relieved the symptoms of polydipsia, polyphagia, emaciation and hyperglycemia in streptozotocin (STZ)-induced diabetic mice to a certain extent. Further, by using the quantitative real-time PCR (qPCR) assay and immunofluorescence staining, EPO was proved to promote the insulin secretion by reducing pancreatic inflammation and apoptosis in diabetic mice. In summary, our results indicate that the mitigation of EPO on pancreatic damage might be an effective way to ameliorate the diabetes mellitus.

Structural Characterization, Antioxidant Activity, and Biomedical Application of Astragalus Polysaccharide Degradation Products

To study the antioxidant capacity of Astragalus polysaccharides (APS) with different molecular weights, we used hydrogen peroxide to degrade original Astragalus polysaccharide (APS0) with an initial molecular weight of 11.03 kDa and obtained three degraded polysaccharides with molecular weights of 8.38 (APS1), 4.72 (APS2), and 2.60 kDa (APS3). The structures of these polysaccharides were characterized by 1H NMR, 13C NMR, FT-IR, and GC/MS. The degradation process did not cause significant changes in the main chain structure of APS. The monosaccharide component of APS before and after degradation was slightly changed. The antioxidant ability in vitro (removing hydroxyl and ABTS radicals and reducing ability) and in cells (superoxide dismutase and malondialdehyde generation) of these polysaccharides is closely related to their molecular weight. If the molecular weight of APS is very high or low, it is not conducive to their activity. Only APS2 with moderate molecular weight showed the greatest antioxidant activity and ability to repair human kidney epithelial (HK-2) cells. Therefore, APS2 can be used as a potential antistone polysaccharide drug.

Antiviral Activity against Avian Leucosis Virus Subgroup J of Degraded Polysaccharides from Ulva pertusa

Avian Leukosis Virus Subgroup J (ALV-J), a retrovirus of avian, has caused enormous economics losses to poultry industry around the world. Polysaccharides from marine algae are featured diversity bioactivities. To find the potential effect to prevent ALV-J spread, in this study, polysaccharides from Ulva pertusa (UPPs) and four low molecular weight (Mw) U. pertusa polysaccharides (LUPPs) were prepared and their functions on ALV-J were investigated. Firstly, LUPPs were obtained by hydrogen peroxide (H2O2) oxidative degradation. The effects of degradation conditions on Mw of the UPP were also investigated. Results showed that the H2O2 oxidative degradation method could degrade UPP effectively, and the degradation was positively related to H2O2 concentration and temperature and negatively to pH. The chemical characteristics of UPP and LUPPs were also determined. Afterwards, the anti-ALV-J activity of the polysaccharides were carried out in vitro. Results showed that UPP and LUPPs could inhibit ALV-J and LUPP-3 and Mw of 4.3 kDa exerted the strongest suppression. The action phase assay showed that LUPP-3 could bind with the viral particles and prevented ALV-J adsorption onto the host cells. And the ALV-J relative gene and gp85 protein expression were significantly suppressed after being administration with LUPP-3. Therefore, the low Mw polysaccharides from U. pertusa have great potential as an anti-ALV-J drug alternative.

Low-Molecular-Weightt Polysaccharides From Pyropia yezoensis Enhance Tolerance of Wheat Seedlings (Triticum aestivum L.) to Salt Stress

Soil salinity is one of the major issues worldwide that affects plant growth and reduces agricultural productivity. Seaweed polysaccharides have been shown to promote crop growth and improve the resistance of plant to abiotic stresses. Pyropia yezoensis is a commercially important edible red alga in Southeast Asia. However, there is little research on the application of polysaccharides from P. yezoensis in agriculture. The molecular weight (MW) of polysaccharides influences their properties. Therefore, in this study, four representative polysaccharides from P. yezoensis (PP) with different MWs (MW: 3.2, 10.5, 29.0, and 48.8 kDa) were prepared by microwave-assisted acid hydrolysis. The relationship between the degradation of polysaccharides from P. yezoensis (DPP) and their effects on plant salt tolerance was investigated. The results showed that exogenous PP and DPPs increased wheat seedling shoot and root lengths, and fresh and dry weights, alleviated membrane lipid peroxidation, increased the chlorophyll content and enhanced antioxidant activities. The expression level examination analysis of several Na⁺/K⁺ transporter genes suggested that DPPs could protect plants from the damage of salt stress by coordinating the efflux and compartmentation of Na⁺. The results demonstrated that polysaccharides could regulate antioxidant enzyme activities and modulate intracellular ion concentration, thereby to protect plants from salt stress damage. Furthermore, there was a significant correlation between the tolerance of wheat seedlings to salt stress and MW of polysaccharides. The results suggested that the lower-MW samples (DPP1, 3.2 kDa) most effectively protect wheat seedlings against salt stress.

Directional preparation of anticoagulant-active sulfated polysaccharides from Enteromorpha prolifera using artificial neural networks

The sulfated polysaccharides from Enteromorpha prolifera (PE) are a potential source of anticoagulant agents. In this study, the PE was degraded by specific degradase and five hydrolysis products with different molecular weights were prepared. The product of 206 kDa is a kind of high rhamnose-containing polysaccharide with sulfate ester (34.29%). It could effectively prolong the activated partial thromboplastin time (APTT), which indicated inhibition of the intrinsic coagulation pathway. The artificial neural network (ANN) was built to realize the directional preparation of anticoagulant-active polysaccharides. Based on monitoring glucose concentration on-line, a visualization system of enzymatic hydrolysis was developed to simplify the operation of ANN. The model could be further applied to predict molecular weights of polysaccharides that possess diverse biological activities.

Total fractionation and characterization of the water-soluble polysaccharides isolated from Enteromorpha intestinalis

Water-soluble crude polysaccharides (WE) were extracted from the Enteromorpha intestinalis with hot water and further fractionated on a DEAE-52 Cellulose chromatography column and Sepharose CL-6B gel-permeation chromatography to afford one neutral fraction (WE-11) and five acidic fractions (WE-21, WE-31, WE-32, WE-41 and WE-42). Monosaccharide analysis showed that WE-32, WE-41 and WE-42 were all composed of Rha and GlcA, WE-21 and WE-31 contained Man and Rha, and WE-11 was composed of GlcA and Xyl. The molecular weight of WE-11, WE-21, WE-31 WE-32, WE-41 and WE-42 were 2.23 × 10⁵, 1.42 × 10⁵, 1.42 × 10⁵, 2.62 × 10⁴, 2.23 × 10⁵ and 8.09 × 10^4, respectively. Then, antioxidant activities in vitro were investigated on the basis of DPPH radical assay, reducing power assay, hydroxyl radical assay and superoxide radical assay. Of all polysaccharides fractions, WE-32 and WE-41 had relative higher content of sulfate and GlcA. In addition, WE-32 and WE-41 showed relative stronger antioxidant activity and inhibitory activity in vitro. The antioxidant activities of polysaccharides were not a function of a single factor but a combination of several factors, such as monosaccharide composition, molecular weights, protein content, uronic acid and sulfate content.

In vitro biological properties and health benefits of a novel sulfated polysaccharide isolated from Cymodocea nodosa

BACKGROUND

During the last few decades, there has been a growing interest in the search for novel bioactive compounds from marine origins.

METHODS

The present study is the first to determine the molecular characterization which it was deposited in the genebank database, to investigate and evaluate the biological properties of sulfated polysaccharide from Cymodocea nodosa (CNSP) seagrass.

RESULTS

The results revealed that CNSP had high activity in total antioxidant assay (59.03 mg ascorbic acid equivalents/g extract), reducing power (OD = 0.3), DPPH radical scavenging (IC₅₀ = 1.22 mg/ml) and ABTS radical scavenging (IC₅₀ = 1.14 mg/ml). It was also noted to exhibit antimicrobial activity against a wide range of microorganisms, with important inhibition zones. The results revealed that CNSP was able to inhibit the proliferation of Hela cell lines with a dose-dependent manner.

CONCLUSION

Overall, the results presented in this study demonstrate that CNSP has several attractive antioxidant, antimicrobial and antiproliferative properties with potential benefits towards health.

A novel low molecular weight Enteromorpha polysaccharide-iron (III) complex and its effect on rats with iron deficiency anemia (IDA)

Iron deficiency anemia (IDA) is a common nutritional disease that affects normal erythropoiesis. Traditional iron supplements usually cause gastrointestinal irritation. In this study, a novel low-molecular-weight polysaccharide from Enteromorpha prolifera (LPE) was prepared by oxidation degradation, and LPE-iron (III) complex was synthesized and characterized. The molecular weight of LPE-iron (III) complex was 21.25kDa, and iron content was 25%. The therapeutic effects of LPE-iron (III) complex on IDA were investigated in rats. The hematological indices and organ coefficients of the rats were analyzed. Results showed a dose-dependent relationship, and a prior intragastric administration of LPE-iron (III) complex (2mg Fe/kg body weight) exhibited considerable effect when compared with the positive control. Therefore, LPE-iron (III) complex could be exploited as a new iron fortifier.

Degradation of Polysaccharides from Grateloupia filicina and Their Antiviral Activity to Avian Leucosis Virus Subgroup J

In this study, polysaccharides from Grateloupia filicinia (GFP) were extracted and several low molecular weight (Mw) G. filicina polysaccharides (LGFPs) were prepared by the hydrogen peroxide (H₂O₂) oxidation method. Additionally, the effect of different experimental conditions on the degradation of GFP was determined. Results showed that the GFP degradation rate was positively related to H₂O₂ concentration and temperature, and negatively related to pH. Chemical analysis and Fourier transform infrared spectra (FT-IR) of GFP and LGFPs showed that the degradation caused a slight decrease of total sugar and sulfate content. However, there was no obvious change for monosaccharide contents. Then, the anti-ALV-J activity of GFP and LGFPs were determined in vitro. Results revealed that all of the samples could significantly inhibit ALV-J and lower Mw LGFPs exhibited a stronger suppression, and that the fraction LGFP-3 with Mw 8.7 kDa had the best effect. In addition, the reaction phase assays showed that the inhibition effect was mainly because of the blocking virus adsorption to host cells. Moreover, real-time PCR, western-blot, and IFA were further applied to evaluate the blocking effects of LGFP-3. Results showed that the gene relative expression and gp85 protein for LGFPS-3 groups were all reduced. Data from IFA showed that there was less virus infected cells for 1000 and 200 μg/mL LGFPS-3 groups when compared to virus control. Therefore, lower Mw polysaccharides from G. filicina might supply a good choice for ALV-J prevention and treatment.

Development of genipin-crosslinked fucoidan/chitosan-N-arginine nanogels for preventing Helicobacter infection

AIM

This study aims to validate the anti-Helicobacter pylori efficacy of amoxicillin-loaded nanoparticles and nanogels with pH-responsive and site-specific drug release properties against H. pylori infection.

MATERIALS & METHODS

Genipin-crosslinked low molecular weight fucoidan/chitosan-N-arginine nanogels (FCSA) were prepared for targeted delivery of amoxicillin to the site of H. pylori infected AGS gastric epithelial cells.

RESULTS

The negatively charged nanogels (n-FCSA) adhered to H. pylori and exhibited pH-responsive drug release property to reduce cytotoxic effects in H. pylori infected AGS cells.

CONCLUSION

These in vitro findings suggest that n-FCSA nanogels are potential carriers for H. pylori specific delivery of antibacterial agents, and provide the basis for further studies on the clinical use of the nanogels.

Sulfated modification, characterization, and antioxidant and moisture absorption/retention activities of a soluble neutral polysaccharide from Enteromorpha prolifera

A purified polysaccharide from Enteromorpha prolifera (PEP) with a molecular mass of 147.8kDa, was prepared by hot-water extraction method and purified by anion-exchange chromatography and gel filtration chromatography. Low Mw polysaccharide of E. prolifera (LEP, 44.8kDa) was obtained by enzymatic degradation. Sulfated derivatives of the two different Mw polysaccharides were synthesized by chlorosulfonic acid/pyridine method, and the degrees of substitution of SPEP and SLEP were 0.57 and 0.81, respectively. Physicochemical properties and FT-IR spectra showed that enzymatic degradation and sulfated modification of polysaccharides were successful. ¹³C NMR analysis showed that the sulfate groups mainly attached to C-6 of rhamnose. Moreover, the study revealed that enzymatic degradation and sulfated modification of polysaccharides improved significantly superoxide, hydroxyl and DPPH radicals scavenging activities in vitro, and enhanced obviously moisture absorption/retention capacities. Therefore, these results demonstrated that molecular weight and sulfate groups had obvious effects on antioxidant activities and moisture absorption/retention abilities of the polysaccharides from E. prolifera.

Antioxidant, antibacterial and anti-aging activities of intracellular zinc polysaccharides from Grifola frondosa SH-05

In present work, the strain of Grifola frondosa SH-05 was used as a vector of zinc biotransformation to produce the IZPS. The bioactivities including antioxidant and antibacterial activities in vitro and anti-aging properties in vivo of IZPS were investigated comparing with the IPS. The results which were in consistent with the results of histopathology assay demonstrated that the IZPS had superior antioxidant and anti-aging activities by scavenging the hydroxyl and DPPH radicals, increasing enzyme activities, decreasing the MDA contents and ameliorating the anile condition of mice. Besides, the IZPS also showed potential antibacterial activities. The IZPS with higher bioactivities was composed of were Rha, Ino and Glu with a molar ratio of 4.7:3.6:1. These conclusions indicated that the IZPS might be a potential source of natural antioxidant, antibacterial agent and anti-aging agent.

In vitro fermentation of sulfated polysaccharides from E. prolifera and L. japonica by human fecal microbiota

In vitro fermentation of the sulfated polysaccharides from seaweeds Enteromorpha prolifera and Laminaria japonica and their prebiotic effects on human fecal microbiota were investigated in this study. The sulfated polysaccharides were fermented in vitro for 48h by human fecal cultures. When 0.8g MWCOL (polysaccharides MWCO<30kD) from L. japonica was fermented, the pH in fecal cultures decreased from 6.5 to 5.1 and the levels of short chain fatty acids, such as acetic, butyric and lactic acids all significantly increased. After 48h fermentation, 0.8g MWCOL showed good effect on modulating the gut microflora balance, because the beneficial strains (Lactobacillus and Bifidobacterium) were both significantly higher than those in control group (p<0.05). As far as we know, this is the first report that consumption of sulfated polysaccharides from E. prolifera and L. japonica is beneficial to the ecosystem of the intestinal tract by increasing the populations of probiotics and short chain fatty acids. Furthermore, our reports indicated that molecular weight of sulfated polysaccharide from marine algae is related to its prebiotic effects.

Enhancing the Antioxidant Ability of Trametes versicolor Polysaccharopeptides by an Enzymatic Hydrolysis Process

Polysaccharopeptides (PSPs) are among the main bioactive constituents of Trametes versicolor (T. versicolor). The purpose of this research was to investigate the antioxidant activities of enzymatic hydrolysates obtained from T.versicolor polysaccharopeptides by 80 U/mL β-1,3-glucanase (PSPs-EH80). The half-inhibitory concentration (IC₅₀) of PSPs-EH80 in metal chelating assay, ABTS and DPPH radical scavenging test results were 0.83 mg/mL, 0.14 mg/mL and 0.52 mg/mL, respectively, which were lower than that of PSPs-EH 20 U/mL. The molecular weights of the PSPs-EH80 hydrolysates were 300, 190, 140 and 50 kDa, respectively, and the hydrolysis of polysaccharides by β-1,3-glucanase did not change the original functional group. PSPs-EH80 reduced the reactive oxygen species (ROS) content at least twice that of treatment without PSPs-EH80. In addition, an oxidative damage test showed that PSPs-EH80 can improve HaCaT cell survival. According to our results, PSP demonstrates the potential of anti-oxidative damage; besides, enzyme hydrolysis can improve the ability of the PSP.

Optimization of Mycelia Selenium Polysaccharide Extraction from Agrocybe cylindracea SL-02 and Assessment of their Antioxidant and Anti-Ageing Activities

The aim of the present study was to optimize the purification of mycelia selenium polysaccharides (MSPS) from Agrocybe cylindracea SL-02 and characterize their in vitro antioxidant and in vivo anti-ageing activities. The Box-Behnken experimental design (BBD) was evaluated, which showed that the optimum conditions included an extraction temperature of 94.99°C, a pH of 9 and a precipitation temperature of 12°C, and the predicted yield was 11.036 ± 0.31%. The in vitro antioxidant assay demonstrated that MSPS had potential effects on scavenging and enhanced the reducing power of reactive oxygen species. The in vivo anti-ageing evaluation showed that MSPS significantly reduced the malonaldehyde (MDA) contents and total cholesterol (CHOL) levels, and remarkably improved the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and total antioxidant capacity (T-AOC) in mice in response to D-galactose-induced ageing. Furthermore, the characteristic analysis of MSPS indicated a selenium content of 1.76 ± 0.10 mg/g at a concentration of 6 μg/mL in liquid media and a monosaccharide composition of rhamnose, arabinose, mannose, glucose and galactose at a molar ratio of 29:3:1:18.8:2.7. These results suggest that MSPS might be suitable for functional foods and natural drugs on preventing the ageing progress induced by toxic chemicals.

Fucoidans in Nanomedicine

Fucoidans are widespread cost-effective sulfated marine polysaccharides which have raised interest in the scientific community over last decades for their wide spectrum of bioactivities. Unsurprisingly, nanomedicine has grasped these compounds to develop innovative therapeutic and diagnostic nanosystems. The applications of fucoidans in nanomedicine as imaging agents, drug carriers or for their intrinsic properties are reviewed here after a short presentation of the main structural data and biological properties of fucoidans. The origin and the physicochemical specifications of fucoidans are summarized in order to discuss the strategy of fucoidan-containing nanosystems in Human health. Currently, there is a need for reproducible, well characterized fucoidan fractions to ensure significant progress.

Structural characterization and anti-aging activity of a novel extracellular polysaccharide from fungus Phellinus sp. in a mammalian system

Little is known about the chemical structure of purified extracellular polysaccharides from Phellinus sp., a fungal species with known medicinal properties. A combination of IR spectroscopy, methylation analysis and NMR were performed for the structural analysis of a purified extracellular polysaccharide derived from Phellinus sp. culture, denoted as SHP-1, along with an evaluation of the anti-aging effect in vivo of the polysaccharide supplementation. The structure of SHP-1 was established, with a backbone composed of →2,4)-α-d-glucopyranose-(1→ and →2)-β-d-mannopyranose-(1→ and two terminal glucopyranose branches. Biochemical analysis from mammalian animal experiments demonstrated that SHP-1 possesses the ability to enhance antioxidant enzyme activities, such as catalase (CAT) and superoxide dismutase (SOD) activities, Trolox equivalent antioxidant capacity (TEAC) in serum of d-galactose-aged mice, while reducing lipofuscin levels, another indicator of cell aging, indicating a potential association with anti-aging activities in a dose dependent manner. This compound had a favourable influence on immune organ indices, and a marked amelioration ability of histopathological hepatic lesions such as necrosis, karyolysis and reduced inflammation and apoptosis in mouse hepatocytes. These results suggest that SHP-1 has strong antioxidant activities and a significant protective effect against oxidative stress or hepatotoxicity induced by d-galactose in mice and it could be developed as a food ingredient or a pharmaceutical to prevent many age-associated diseases such as major depressive disorder and hepatotoxicity. To our knowledge, this is the first report on the antioxidant effects of a novel purified exopolysaccharide derived from Phellinus sp.

Inhibition of hydrogen peroxide induced injuring on human skin fibroblast by Ulva prolifera polysaccharide

Ulva prolifera can protect human skin fibroblast from being injured by hydrogen peroxide. This work studied the composition of Ulva prolifera polysaccharide and identified its physicochemical properties. The results showed that the cell proliferation of 0.5mg/mL crude polysaccharide was 154.4% of that in negative control group. Moreover, ROS detection indices, including DCFH-DA, GSH-PX, MDA and CAT, indicated that crude polysaccharide could improve cellular ability to scavenge free radical and decrease the injury on human skin fibroblast by hydrogen peroxide. In purified polysaccharide, the activity of fraction P1-1 was the highest, with 174.6% of that in negative control group. The average molecular weight of P1-1 was 137kD with 18.0% of sulfate content. This work showed the inhibition of hydrogen peroxide induced injuries on human skin fibroblast by Ulva prolifera polysaccharide, which may further evaluate the application of U. prolifera on cosmetics.

Bacterial Diversity in Submarine Groundwater along the Coasts of the Yellow Sea

Submarine groundwater (SGD) is one of the most significant pathways for the exchange of groundwater and/or source of nutrients, metals and carbon to the ocean, subsequently cause deleterious impacts on the coastal ecosystems. Microorganisms have been recognized as the important participators in the biogeochemical processes in the SGD. In this study, by utilizing 16S rRNA-based Illumina Miseq sequencing technology, we investigated bacterial diversity and distribution in both fresh well water and brackish recirculated porewater along the coasts in the Yellow Sea. The results showed that Actinobacteria and Betaproteobacteria, especially Comamonas spp. and Limnohabitans spp. were dominated in fresh well samples. Distinct patterns of bacterial communities were found among the porewater samples due to different locations, for examples, Cyanbacteria was the most abundant in the porewater samples far from the algal bloomed areas. The analysis of correlation between representative bacterial taxonomic groups and the contexture environmental parameters showed that fresh well water and brackish porewater might provide different nutrients to the coastal waters. Potential key bacterial groups such as Comamonas spp. may be excellent candidates for the bioremediation of the natural pollutants in the SGD. Our comprehensive understanding of bacterial diversity in the SGD along the coasts of the Yellow Sea will create a basis for designing the effective clean-up approach in-situ, and provide valuable information for the coastal management.