A rhamnan-type sulfated polysaccharide with novel structure from Monostroma angicava Kjellm (Chlorophyta) and its bioactivity

Structural characterization of a novel fucoidan from Sargassum horneri for anticancer drug delivery

A fucoidan SHF from Sargassum horneri was obtained. Nanoparticles were prepared using SHF (F) and chitosan (Cs) at F/Cs mass ratios of 1.0/3.0, 1.0/1.5, 1.0/1.0, 1.5/1.0 and 3.0/1.0. The nanoparticles showed a high binding affinity for P-selectin, especially at the ratio of 1.5/1.0. The pH-responsive drug release of doxorubicin (DOX)-loaded nanoparticles was evaluated to select the nanoparticle with low DOX release in blood (pH 7.4) but high release upon entering the endosome/lysosome (pH 4.5-5.5) of cancer cells. Results indicated that the DOX release rate significantly increased at 1.5/1.0 when the medium pH decreased from 7.4 to 5.5. Moreover, DOX-loaded nanoparticles showed improved inhibitory effects against a metastatic breast cancer cell line (MDA-MB-231) compared to free DOX at equivalent concentrations. Therefore, nanoparticles based on SHF achieved efficient delivery of DOX. SHF is an excellent material for the tumor-targeting drug delivery systems. To further understand the structural characteristics of tumor-targeting fucoidan, the fine structure of SHF was analyzed. The main chain of SHF might be cross-linked by →4)-α-l-Fucp(2,3SO4)-(1→ and →3,2)-β-d-Galp-(1→, with the →4,6)-β-d-Manp-(1 → 3,2)-β-d-Galp-(1 → 4,6)-β-d-Manp-(1→ fragment interspersed between them. Notably, dual-sulfated fucose residues accounted for a large proportion.

Alkali-extracted rhamnogalactoarabinan from Chaetomorpha linum: Characterisation and anti-type 2 diabetic effect

Sulphated galactoarabinans, extracted from members belonging to the Cladophoraceae (Chlorophyceae) family, have been reported to have potential as novel anti-diabetic agents. However, relatively few studies have investigated this research topic. In the present study, a water-soluble polysaccharide designated CBS2 was obtained from Chaetomorpha linum using dilute alkaline solution, preparative anion exchange, and size-exclusion chromatography. Chemical and high-performance liquid chromatography analyses revealed that CBS2 is a sulphated rhamnogalactoarabinan. Gas chromatography-mass spectrometry and nuclear magnetic resonance analyses revealed that the backbone of CBS2 was primarily made up of 4-linked β-L-arabinopyranose, which was sulphated at C-2/C-3. The branches were primarily composed of 4-linked-β-d-galactopyranose and positioned at C-3 of 4-linked β-L-arabinopyranose. Transmission electron microscopy and thioflavin T fluorescence experiments showed that CBS2 successfully suppressed human islet amyloid polypeptide (hIAPP) aggregation in vitro. In NIT-1 cells, CBS2 reduced hIAPP-induced cytotoxicity. CBS2 markedly lowered the production of intracellular reactive oxygen species and oxidative stress induced by hIAPP aggregation in NIT-1 cells. In addition, CBS2 co-localised with mitochondria and protected mitochondrial function from hIAPP aggregation-induced damage by stabilising the mitochondrial membrane potential. These data suggest that CBS2 may potentially serve as an anti-diabetic agent for the treatment of type 2 diabetes mellitus.

Fucoidan derived from Saccharina japonica: structural characterization and amelioration of high-fat-diet induced obesity in male C57BL/6 J mice via modulating the gut microbiota and lipid metabolites

Fucoidan has great potential for the prevention and treatment of obesity. This study aimed to determine the detailed structure of two fucoidan fractions (LF3-1 and LF4-1) from Saccharina japonica (S. japonica) and its mechanism for treating obesity. LF3-1 and LF4-1, with a molecular weight of 305.3 kDa and 182.1 kDa, respectively, were obtained from S. japonica. The backbone of LF3-1 consisted of →1,3)-α-L-Fucp4S-(1 → and →1,3)-β-D-Galp6S-(1→, branched with α-L-Fucp, β-D-Galp, and β-D-Manp. LF4-1's backbone consisted of →1,3)-α-L-Fucp4S-(1 → and →1,6)-β-D-Galp3S-(1→, branched with α-L-Fucp, β-D-Galp, and β-D-Manp. Over 24 weeks in high-fat-diet-fed C57BL/6 J mice, a mixture of LF3-1 and LF4-1 (100 and 300 mg/kg/d FUC) effectively reduced body weight and insulin resistance, ameliorated dyslipidemia, protected the intestinal barrier integrity, up-regulated Ucp-1, Prdm16 and Pgc-1α expression to inhibit fat accumulation, up-regulated Ppar-α, Ppar-γ, and Cpt-1 expression and down-regulation Fas, Lxr, and Srebp-1c expression to regulate lipid metabolism, and down-regulated expression of Tnf-α, Il-6, Il-1β, and Mcp-1 to ameliorate inflammation. In addition, FUC increased the abundance of Bacteroidetes and Lactobacillus. Lipid metabolomics analysis showed that Erysipelatoclostridium, Lachnoclostridium, Ruminococcaceae_UCG-014, and Staphylococcus may be involved in regulating sphingosine (SPH). This study revealed the structure properties and the potential of the application of FUC in the amelioration of obesity.

Anticoagulant and angiotensin-converting enzyme inhibitory activities of a fucoidan from Sargassum horneri and its low molecular weight fragments prepared by acid degradation

A purified fucoidan SF (348 kDa) was isolated from Sargassum horneri. Six low molecular weight fragments SFs (75-8.1 kDa) were prepared by acid degradation from SF. Anticoagulant properties of SF and SFs were evaluated. SF and SFs with 75-17 kDa had better anticoagulant activities with the activated partial thromboplastin time (APTT) greater than 120 s at 200 μg/mL. The decrease in the molecular weight caused a decrease in anticoagulant activity, and a slight decrease almost resulted in loss of anticoagulant activity when below 17 kDa (APTT < 59 s). Angiotensin-converting-enzyme (ACE)-inhibitory activities were also detected. Only when the molecular weight dropped to a certain extent (8.1 kDa), the fucoidan showed ACE-inhibitory activity (IC50=2.16 mg/mL). Structure analysis indicated the main change of SFs was a reduction in molecular weight. Thus molecular weight is an essential factor affecting the bioactivities. Longer chains were essential to complete thrombin inhibition, whereas ACE-inhibitory activity required shorter ones.

Structure and anticoagulant activity of a galactoarabinan sulfate polysaccharide and its oligosaccharide from the green algae, Codium fragile

A polysaccharide, CZS-0-1, was obtained from the marine green algae Codium fragile using ion-exchange and size-exclusion chromatography. Composition and characteristics analyses showed CZS-0-1 was a sulfated galactoarabinan consisting of arabinose, galactose and a small amount of glucose in a ratio of 9:2:1 with 21% sulfate content and a molecular weight of 810 kDa. Structural properties were determined using desulfation and methylation analyses combined with instrument analysis. The results showed that the backbone of CZS-0-1 was (1 → 3)-β-L-Arap. Its O-4 and/or O-2 positions showed sulfate modification; additionally, it had 10% of (1 → 3)-β-D-Galp branches at the O-4 position of the (1 → 3)-β-L-Arap. The galactose side chains also had sulfate modification at the O-4 or O-6 position. The structure of CZS-0-1 was further confirmed by Top-down analysis of the oligosaccharides after oxidated hydrolysis by mass spectrometry. CZS-0-1 exhibited significant heparin-like anticoagulant activity. It exerted anticoagulant effects by inhibiting FIIa and FXa activities with the presence of heparin cofactors. The anticoagulant activity of CSZ-0-1 was closely related to the molecular weight, and the reduction of molecular weight may lead to a significant decrease in the anticoagulant activity. This study demonstrated that the green algae, Codium fragile can be considered as a useful resource for bioactive polysaccharides.

An arabinoxylan (AOP70-1) isolated from Alpinia oxyphylla alleviates neuroinflammation and neurotoxicity by TLR4/MyD88/NF-κB pathway

Alpinia oxyphylla is famous for its neuroprotective and memory-improving effects. A crude polysaccharide AO70 from A. oxyphylla remarkably ameliorated neuroinflammation and cognitive dysfunction in Alzheimer's disease mice. This study aimed to explore the bioactive component of AO70 and its mechanism of action. A homogeneous polysaccharide (AOP70-1) rich in arabinose and xylose was purified from AO70, which was consisted of α-L-Araf-(1→, →5)-α-L-Araf-(1→, β-D-Xylp-(1→,→2,4)-β-D-Xylp-(1→, →2,3,4)-β-D-Xylp-(1→, α-L-Rhap-(1→, α-D-Manp-(1→, →4)-α-D-Glcp-(1→, →4)-α-D-GlcpA-(1→, β-D-Galp-(1→, →2)-α-D-Galp-(1→, →6)-α-D-Galp-(1 → and →3,6)-α-D-Manp-(1 →. AOP70-1 (2.5, 5, 10 μM) significantly suppressed NO, IL-1β, and TNF-α production in a concentration-dependent manner and inhibited the migration of BV2 microglia. AOP70-1 inhibited LPS-mediated activation of Toll-like receptor 4 (TLR4), myeloid differentiation primary response protein (MyD88), and nuclear factor kappa B (NF-κB). Moreover, AOP70-1 exerted neuroprotection on SH-SY5Y cells and primary neurons by reducing neuronal apoptosis (72 %, 44 %), alleviating ROS accumulation (63 %, 55 %), and improving mitochondrial membrane potential (63 %, 77 %). Overall, AOP70-1 is one of the major bioactive components in AO70 from A. oxyphylla, which has great potential in the prevention and treatment of neuroinflammation.

Semisynthesis of new sulfated heterorhamnan derivatives obtained from green seaweed Gayralia brasiliensis and evaluation of their anticoagulant activity

Marine green algae produce sulfated polysaccharides with diverse structures and a wide range of biological activities. This study aimed to enhance the biotechnological potential of sulfated heterorhamnan (Gb1) from Gayralia brasiliensis by chemically modifying it for improved or new biological functions. Using controlled Smith Degradation (GBS) and O-alkylation with 3-chloropropylamine, we synthesized partially water-soluble amine derivatives. GBS modification increase sulfate groups (29.3 to 37.5 %) and α-l-rhamnose units (69.9 to 81.2 mol%), reducing xylose and glucose, compared to Gb1. The backbone featured predominantly 3- and 2-linked α-l-rhamnosyl and 2,3- linked α-l-rhamnosyl units as branching points. Infrared and NMR analyses confirmed the substitution of hydroxyl groups with aminoalkyl groups. The modified compounds, GBS-AHCs and GBS-AHK, exhibited altered anticoagulant properties. GBS-AHCs showed reduced effectiveness in the APTT assay, while GBS-AHK maintained a similar anticoagulant activity level to Gb1 and GBS. Increased nitrogen content and N-alkylation in GBS-AHCs compared to GBS-AHK may explain their structural differences. The chemical modification proposed did not enhance its anticoagulant activity, possibly due to the introduction of amino groups and a positive charge to the polymer. This characteristic presents new opportunities for investigating the potential of these polysaccharides in various biological applications, such as antimicrobial and antitumoral activities.

Hypoglycemic Effects of Gynura divaricata (L.) DC Polysaccharide and Action Mechanisms via Modulation of Gut Microbiota in Diabetic Mice

Aiming to provide a basis for the application of Gynura divaricata (L.) DC polysaccharide (GDP) in functional foods, the hypoglycemic effects of GDP, and action mechanisms, were investigated. Results showed that GDP effectively inhibited α-glucosidase and remarkably increased the glucose absorption, glycogen content, and pyruvate kinase and hexokinase activities of insulin-resistant HepG2 cells, indicating its potent in vitro hypoglycemic effect. In streptozotocin-induced type 2 diabetes mice, GDP significantly improved various glycolipid metabolism-related indices in serum and liver, e.g., fasting blood glucose, oral glucose tolerance, glycosylated serum protein content, serum insulin level, antioxidant enzyme activities, TG, TC, LDL-C, and HDL-C levels, and hepatic glycogen content, and recovered the structure of gut microbiota to the normal level. It was also found that GDP significantly affected the expression of related genes in the PI3K/Akt, AMPK, and GS/GSK-3β signaling pathways. Therefore, GDP regulates blood glucose possibly by directly inhibiting α-glucosidase, exerting antioxidant activity, and regulating intestinal microbiota.

Preparation, structures, and biological functions of rhamnan sulfate from green seaweed of the genus Monostroma: A review

Rhamnan sulfate, a rhamnose-rich sulfated polysaccharide, is present in the cell walls of green seaweed belonging to the genus Monostroma. This macromolecule demonstrates promising therapeutic properties, including anti-coagulant, thrombolytic, anti-viral, anti-obesity, and anti-inflammatory activities, which hold potential applications in food and medical industries. However, rhamnan sulfate has not garnered as much attention from researchers as other seaweed polysaccharides, including alginate, carrageenan, and fucoidan. This review discusses the extraction and purification techniques of rhamnan sulfate, delves into its chemical structures and related elucidation approaches, and provides an overview of its biological functions. Future research should focus on the structure-activity relationship of rhamnan sulfate and the industrial preparation of rhamnan sulfate with a specific homogeneous structure to facilitate its practical applications.

Structure and Anticoagulant Activity of a Galactofuranose-Containing Sulfated Polysaccharide from the Green Seaweed, Codium isthmocladum

A water-soluble sulfated polysaccharide, F2-1, was obtained from the marine green alga, Codium isthmocladum, using ion-exchange and size-exclusion chromatography. Structure analysis showed that the F2-1 was a sulfated arabinan comprising Ara, Rha, Man, Gal, and Xyl with an 18% sulfate content and a molecular weight of 100 kDa. Methylation analysis combined with desulfation, GC-MS, IR, and NMR spectroscopy showed that the backbone of F2-1 was →4)-β-L-Arap(1→ residue. Its 2-O and/or 3-O positions showed sulfate modification; additionally, the 2-O or 3-O position showed branch points. The side chains were composed of →5)-β-D-Galf, (1→2,6)-β-D-Galf(1→, (1→2)-β-L-Rhap4S, →4)-α-D-Glcp(1→, and terminal α-D-Galp(1→ and β-D-Xylp(1→. Polysaccharides containing β-D-galactofuranose are rarely found in seaweed. F2-1 exhibited significant anticoagulant activity in vitro. Our findings suggested that the green-tide alga, Codium isthmocladum, can be considered as a useful resource for bioactive polysaccharides.

Concise review of green algal genus Monostroma Thuret

Monostroma (Ulotrichales, Chlorophyta) is the most intensively cultivated genus among green seaweeds, accounting for over 90% of total green algal cultivation. It is commonly found in the eulittoral zones of marine and estuarine habitats, thus contributing significantly to the ecology of the coastal ecosystem. Morphologically, the frond of Monostroma is blade-like with eponymous one-cell thickness; therefore, it is also known as "Slender sea lettuce". Monostroma nitidum is often used for salad ingredients, boiled tsukudani, soups, etc., due to its health benefits. Monostroma kuroshiense is commercially cultivated in East Asia and South America for the edible product "hitoegusa-nori" or "hirohano-hitoegusa nori", popular sushi wraps. This genus remains one of the well-studied seaweed genera for ecophysiology, habitat-dependent seasonality of its growth pattern, gametangial ontogeny and phylogenetics. Moreover, rhamnan sulfate (RS), a sulfated polysaccharide, is the main component of the fiber extracted from M. nitidum and studied for various biological activities. This review presents the taxonomy, morphology, anatomy, life history, distribution, ecology, physiology, cultivation and harvesting, chemical composition, and biotechnological applications of this genus.

Structural insight into a glucomannan-type extracellular polysaccharide produced by a marine Bacillus altitudinis SORB11 from Southern Ocean

Extracellular polysaccharide (EPS) produced by a deep-sea, psychrotolerant Bacillus altitudinis SORB11 was evaluated by considering physiochemical nature and structural constituents. The productivity of crude EPS was measured ~ 13.17 g L^-1. The surface topography of the crude EPS showed a porous, webbed structure along with a branched coil-like configuration. The crystalline crude EPS contained a high amount of sulfur. Further, the crude EPS was subjected for purification. The molecular weight of purified EPS was determined ~ 9.8 × 10⁴ Da. The purified EPS was appeared to show glucomannan-like configuration that is composed of → 4)-β-Manp-(1 → and → 4)-β-Glcp-(1 → residues. So, this polysaccharide was comparable to the structure of plant-derived glucomannan. Subsequently, EPS biosynthesis protein clusters like EpsC, EpsD, EpsE, and glycosyltransferase family proteins were predicted from the genome of strain SORB11, which may provide an insight into the production of glucomannan-type of polysaccharide. This low molecular weight linear form of glucomannan-type EPS might be involved to form a network-like unattached aggregation, and helps in cell-to-cell interaction in deep-sea microbial species.

Antidiabetic-activity sulfated polysaccharide from Chaetomorpha linum: Characteristics of its structure and effects on oxidative stress and mitochondrial function

A water-soluble polysaccharide from the green alga Chaetomorpha linum, designated CHS2, was obtained by water extraction, preparative anion-exchange and size-exclusion chromatography. Results of chemical and spectroscopic analyses showed that CHS2 was a sulfated rhamnogalactoarabinan, and its backbone was mainly constituted by 4-linked and 3,4-linked β-l-arabinopyranose with sulfate groups at C-2/C-3 of 4-linked β-l-arabinopyranose. The branching contained 4-linked, 6-linked β-d-galactopyranose and terminal rhamnose residues. Based on the inhibition of human islet amyloid polypeptide (hIAPP) aggregation and morphology change of hIAPP aggregates in in vitro tests, it was proved that CHS2 effectively inhibited the hIAPP aggregation and possessed strong antidiabetic activity. CHS2 was nearly no toxicity in NIT-1 cells and could attenuate hIAPP-induced cytotoxicity. CHS2 may significantly reduce the generation of intracellular reactive oxygen species and hIAPP aggregation-induced oxidative stress in NIT-1 cells. CHS2 was co-localized with mitochondria, and largely protected mitochondria function from hIAPP aggregation-induced damage through stabilizing mitochondrial membrane potential and enhancing the mitochondrial complex I, II or III activity and ATP level. The data demonstrated that CHS2 could have potential prospect to become an antidiabetic drug for type 2 diabetes mellitus treatment.

Purification, Chemical Characterization and Immunomodulatory Activity of a Sulfated Polysaccharide from Marine Brown Algae Durvillaea antarctica

An immunomodulatory polysaccharide (DAP4) was extracted, purified, and characterized from Durvillaea antarctica. The results of chemical and spectroscopic analyses demonstrated that the polysaccharide was a fucoidan, and was mainly composed of (1→3)-α-l-Fucp and (1→4)-α-l-Fucp residues with a small degree of branching at C-3 of (1→4)-α-l-Fucp residues. Sulfate groups were at C-4 of (1→3)-α-l-Fucp, C-2 of (1→4)-α-l-Fucp and minor C-6 of (1→4)-β-d-Galp. Small amounts of xylose and galactose exist in the forms of β-d-Xylp-(1→ and β-d-Gal-(1→. The immunomodulatory activity of DAP4 was measured on RAW 264.7 cells, the results proved that DAP4 exhibited excellent immunomodulatory activities, such as promoted the proliferation of spleen lymphocytes, increased NO production, as well as enhanced phagocytic of macrophages. Besides, DAP4 could also produce better enhancement on the vitality of NK cells. For the high immunomodulatory activity, DAP4 might be a potential source of immunomodulatory fucoidan with a novel structure.

Structural characterization of a P-selectin and EGFR dual-targeting fucoidan from Sargassum fusiforme

In this study, we obtained fucoidans SFP, SHP, STP, and FVP from Sargassum fusiforme, Sargassum horneri, Sargassumthunbergii, and Fucus vesiculosus, respectively. Chitosan/fucoidan nanoparticles (Cs/F NPs) were prepared using the fucoidans mentioned above. SFP NPs and SHP NPs showed strong binding abilities to P-selectin and epithelial growth factor receptor (EGFR). Given the yields from the alga, SFP was first selected to explore the structural characteristics of the P-selectin and EGFR dual-targeting fucoidan. SFP had an estimated molecular weight of 739 kDa and was mainly composed of galactose (26.57%, mol%) and fucose (66.81%), with minor amounts of mannose (2.54%), glucosamine (0.42%), and glucose (3.66%). Galactose and fucose accounted for thevast majority. Further investigation, including methylation analysis, one- and two-dimensional nuclear magnetic resonance, and mass spectroscopy, was performed to reveal the fine structure of SFP. The results indicated that SFP mainly consisted of → 3)-α-l-Fucp-(1→, →4)-α-l-Fucp-(1→, →3,4)-α-l-Fucp-(1→, →3)-β-d-Galp-(1→, and minor → 6)-β-d-Galp-(1→, partially sulfated at the C-4 of → 3)-α-l-Fucp-(1→, C-3 of → 4)-α-l-Fucp-(1→, C-3 of → 6)-β-d-Galp-(1→, and C-6 of → 3)-β-d-Galp-(1 → . Sulfated fuco- and galactofuco-segments formed the branches.

Structural characteristics and immunomodulatory effects of sulfated polysaccharides derived from marine algae

Marine algae are becoming an important source of valuable candidates of functional food that remain unexplored. Compositional analysis showed that marine algae contain essential nutrients, such as carbohydrates, proteins, fats, and minerals, of which polysaccharides are the main bioactive component. Depending on the source, marine algae polysaccharides are sulfated, which have diverse structures and compositions that influence their biological activities. A growing body of evidence has demonstrated that sulfated polysaccharides derived from marine algae (SPs) exhibit various bioactivities, especially immunomodulation. This review aims at summarizing the structural characteristics of SPs, their immunomodulatory effects, and the structural-immunomodulatory activity relationships between them from articles in recent decade, in order to provide a theoretical basis for the further applications of SPs as promising food or feed additives and possible health products to modulate the immune response.

Anti-diabetic activity of a sulfated galactoarabinan with unique structural characteristics from Cladophora oligoclada (Chlorophyta)

The polysaccharide from green alga Cladophora oligoclada, OHSS2, was a sulfated galactoarabinan which was constituted by a backbone of (1 → 4)-β-l-arabinopyranose units with partial sulfate at C-3 of (1 → 4)-β-l-arabinopyranose units. The side chains containing (1 → 4)-β-l-arabinopyranose, (1 → 4)-β-d-galactopyranose and/or (1 → 4,6)-β-d-galactopyranose units were in C-2/C-3 of (1 → 4)-β-l-arabinopyranose units. OHSS2 had strong anti-diabetic activity in vitro assessed by inhibition of human islet amyloid polypeptide (hIAPP) aggregation. The mechanism analysis of anti-diabetic activity showed that OHSS2 diminished the production of intracellular reactive oxygen species and alleviated hIAPP aggregation-induced oxidative stress in NIT-1 cells. OHSS2 stabilized mitochondrial membrane potential, and enhanced the mitochondrial complex I, II or III activity and ATP level. Thus, OHSS2 effectively protected mitochondria from hIAPP aggregation-induced damage. Furthermore, OHSS2 was co-localized with mitochondria and could have a direct influence on mitochondrial function. These results revealed that OHSS2 had potential as a novel anti-diabetic agent.

Structural characterization and tumor microvascular inhibition activity of total polysaccharide from Trametes sanguinea Lloyd

Trametes sanguinea Lloyd total polysaccharide (TsLTP), was obtained by water extraction and ethanol precipitation from T. sanguinea . The structural characterization of TsLTP was elucidated mutually by TsL1 and TsL2, whose mass ratio is 1 : 4. TsL1 is mainly composed of mannose, glucose, galactose, and fucose, and consist of T-Linked-Fuc p , T-Linked-Man p , T-Linked-Gal p , 1,4-Linked-Man p , 1,4-Linked-Glc p , 1,6-Linked-Man p , 1,6-Linked-Gal p , 1,3,4-Linked-Glc p , 1,4,6-Linked-Glc p and 1,3,6- Linked-Glc p , with a molar ratio of 2.1 : 1.7 : 1.4 : 1.0 : 3.6 : 2.0 : 8.6 : 1.3: 2.2: 1.2, while TsL2 mainly comprise of glucose and consist of T-Linked-Glc p , 1,3-Linked-Glc p , 1,4-Linked-Glc p and 1,4,6-Linked-Glc p , with a molar ratio of 1.0 : 2.1 : 7.6 : 1.4. TsLTP exhibited strong inhibitory effects on the migration, invasion, and tube formation of human umbilical vein endothelial cells (iHUVECs) and chick embryo chorioallantoic membrane (CAM) angiogenesis, whereas no inhibitory activity on human TNBC cell lines. Taken together, our study suggests that TsLTP possesses a significant inhibition of tumor microvascular activity both in vitro and in vivo . The study of TsLTP with novel monosaccharide composition and tumor microvascular inhibitory activity might be a beneficial attempt for application of polysaccharide from the genus Trametes in tumor therapy.

Algal polysaccharides and derivatives as potential therapeutics for obesity and related metabolic diseases

The potential and challenges of algal polysaccharides and their derivatives as potential therapeutic agents for obesity and its related metabolic diseases.

Anti-SARS-CoV-2 Activity of Rhamnan Sulfate from Monostroma nitidum

The COVID-19 pandemic is a major human health concern. The pathogen responsible for COVID-19, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), invades its host through the interaction of its spike (S) protein with a host cell receptor, angiotensin-converting enzyme 2 (ACE2). In addition to ACE2, heparan sulfate (HS) on the surface of host cells also plays a significant role as a co-receptor. Our previous studies demonstrated that sulfated glycans, such as heparin and fucoidans, show anti-COVID-19 activities. In the current study, rhamnan sulfate (RS), a polysaccharide with a rhamnose backbone from a green seaweed, Monostroma nitidum, was evaluated for binding to the S-protein from SARS-CoV-2 and inhibition of viral infectivity in vitro. The structural characteristics of RS were investigated by determining its monosaccharide composition and performing two-dimensional nuclear magnetic resonance. RS inhibition of the interaction of heparin, a highly sulfated HS, with the SARS-CoV-2 spike protein (from wild type and different mutant variants) was studied using surface plasmon resonance (SPR). In competitive binding studies, the IC₅₀ of RS against the S-protein receptor binding domain (RBD) binding to immobilized heparin was 1.6 ng/mL, which is much lower than the IC₅₀ for heparin (~750 ng/mL). RS showed stronger inhibition than heparin on the S-protein RBD or pseudoviral particles binding to immobilized heparin. Finally, in an in vitro cell-based assay, RS showed strong antiviral activities against wild type SARS-CoV-2 and the delta variant.

A fucoidan from Sargassum fusiforme with novel structure and its regulatory effects on intestinal microbiota in high-fat diet-fed mice

A fucoidan SFP, having novel structure, was extracted from Sargassum fusiforme. It had a molecular weight of 703 kDa and was composed of fucose and galactose with the ratio of 73.16:26.84 (mol%). Structural analyses showed that it mainly consisted of 1,3-, 1,4-, 1,3,4-linked-α-l-Fucp and 1,3-, 1,6-linked-β-d-Galp, with partial sulfation at C-4, C-3 of fucose units and C-6, C-3 of galactose units. The branches consisted of sulfated fucosyl and galactofucosyl oligosaccharides. The regulatory effects of SFP on the intestinal microbiota in high-fat diet-fed mice were investigated. The high-dosage SFP exhibited good hypolipidemic effects, especially in regulating the high-densitylipoproteincholesterol, non-esterified fatty acid levels and lipase activity. It also significantly decreased the ratio of phyla Firmicutes/Bacteroidetes (P < 0.05). Besides, SFP had certain effects on the richness and diversity of intestinal microbiota. Therefore, SFP exhibited novel structure and certain beneficial effects on the disorder of intestinal microbiota in high-fat diet-fed mice.

Chemical Structure and Anticoagulant Property of a Novel Sulfated Polysaccharide from the Green Alga Cladophora oligoclada

Marine macroalgae are efficient producers of sulfated polysaccharides. The algal sulfated polysaccharides possess diverse bioactivities and peculiar chemical structures, and represent a great potential source to be explored. In the present study, a heparinoid-active sulfated polysaccharide was isolated from the green alga Cladophora oligoclada. Results of chemical and spectroscopic analyses indicated that the sulfated polysaccharide was composed of →6)-β-d-Galp-(1→, β-d-Galp-(1→, →6)-α-d-Glcp-(1→ and →3)-β-d-Galp-(1→ units with sulfate esters at C-2/C-4 of →6)-β-d-Galp-(1→, C-6 of →3)-β-d-Galp-(1→ and C-3 of →6)-α-d-Glcp-(1→ units. The branches consisting of β-d-Galp-(1→ and →6)-β-d-Galp-(1→ units were located in C-3 of →6)-β-d-Galp-(1→ units. The sulfated polysaccharide exhibited potent anticoagulant activity in vitro and in vivo as evaluated by activated partial thromboplastin time (APTT), thrombin time, and the fibrinogen level. For the APTT, the signal for clotting time was more than 200 s at 100 μg/mL in vitro and at 15 mg/kg in vivo. The obvious thrombolytic activity of the sulfated polysaccharide in vitro was also found. The mechanism analysis of anticoagulant action demonstrated that the sulfated polysaccharide significantly inhibited the activities of all intrinsic coagulation factors, which were less than 1.0% at 50 μg/mL, but selectively inhibited common coagulation factors. Furthermore, the sulfated polysaccharide strongly stimulated the inhibition of thrombin by potentiating antithrombin-III (AT-III) or heparin cofactor-II, and it also largely promoted the inhibition of factor Xa mediated by AT-III. These results revealed that the sulfated polysaccharide from C. oligoclada had potential to become an anticoagulant agent for prevention and therapy of thrombotic diseases.

Structure, Antioxidant Activity and In Vitro Hypoglycemic Activity of a Polysaccharide Purified from Tricholoma matsutake

The structure, antioxidant activity and hypoglycemic activity in vitro of a novel homogeneous polysaccharide from Tricholoma matsutake (Tmp) were investigated. Structural features suggested that Tmp was consisted of arabinose (Ara), mannose (Man), glucose (Glc) and galactose (Gal) with a molar ratio of 1.9:13.6:42.7:28.3, respectively, with a molecular weight of 72.14 kDa. The structural chain of Tmp was confirmed to contain →2,5)-α-l-Arabinofuranose (Araf)-(1→, →3,5)-α-l-Araf-(1→, β-d-Glucopyranose (Glcp)-(1→, α-d-Mannopyranose (Manp)-(1→, α-d-Galacopyranose (Galp)-(1→, →4)-β-d-Galp-(1→, →3)-β-d-Glcp-(1→, →3)-α-d-Manp-(1→, →6)-3-O-Methyl (Me)-α-d-Manp-(1→, →6)-α-d-Galp-(1→, →3,6)-β-d-Glcp-(1→, →6)-α-d-Manp-(1→ residues. Furthermore, Tmp possessed strong antioxidant activity and showed the strong inhibitory effect on α-glucosidase and α-amylase activities. Then, a further evaluation found that there was a dramatic improvement in the glucose consumption, glycogen synthesis and the activities of pyruvate kinase and hexokinase when the insulin-resistant-human hepatoma cell line (IR-HepG2) was treated with Tmp. The above results indicated that Tmp had good hypoglycemic activity and also exhibited great potentials in in terms of dealing with type 2 diabetes mellitus.

Chemical structure of native and modified sulfated heterorhamnans from the green seaweed Gayralia brasiliensis and their cytotoxic effect on U87MG human glioma cells

A water-soluble sulfated heterorhamnan (Gb1) was isolated from the green seaweed Gayralia brasiliensis and purified by ultrafiltration, yielding a homogeneous polysaccharide (Gb1r). Both fractions contained rhamnose, xylose, galacturonic and glucuronic acids, galactose, and glucose. Chemical and spectroscopic methods allowed the determination of Gb1 and Gb1r chemical structure. Their backbones were constituted by 3-, 2-, and 2,3-linked rhamnosyl units (1:0.49:0.13 and 1:0.58:0.17, respectively), which are unsulfated (13.5 and 14.6%), disulfated (16.6 and 17.8%) or monosulfated at C-2 (8 and 8.6%) and C-4 (24.5 and 23.4%). Gb1 was oversulfated giving rise to Gb1-OS, which presented ~2.5-fold higher content of disulfated rhamnosyl units than Gb1, as determined by methylation analyses and NMR spectroscopy. Gb1 and Gb1-OS potently reduced the viability of U87MG human glioblastoma cells. Gb1 caused cell cycle arrest in the G₁ phase, increased annexin V-stained cells, and no DNA fragmentation, while Gb1-OS increased the percentage of cells in the S and G₂ phases and the levels of fragmented DNA and cells double-stained with annexin V/propidium iodide, suggesting an apoptosis mechanism. The results suggest that the different effects of Gb1 and Gb1-OS were related to differences in the sulfate content and position of these groups along the polysaccharide chains.

Separation, characterization and hypoglycemic activity in vitro evaluation of a low molecular weight heteropolysaccharide from the fruiting body of Phellinus pini

Edible mushrooms have potential in anti-diabetic phytotherapy. They are rich in natural compounds such as polysaccharides, which have been known to have antihyperlipidemic effects since ancient times. A polysaccharide fraction of PP80 and a contained low molecular-weight (Mw), water-soluble polysaccharide (PPW-1, Mw: 3.2 kDa) were isolated from the fruiting body of Phellinus pini. Both PP80 and PPW-1 possess α-glucosidase inhibition and glucose consumption amelioration in an insulin-resistant HepG2 cell model. The α-glucosidase inhibitory activity of PPW-1 (IC50 = 2.2 ± 0.1 mg mL-1) is significantly (P < 0.01) higher than those of PP80 (IC50 = 13.1 ± 0.5 mg mL-1) and acarbose (IC50 = 4.3 ± 0.2 mg mL-1), behaving in a non-competitive inhibition manner. The structural characterization results indicated that PPW-1 is a homogeneous heteropolysaccharide composed of d-glucose, d-mannose, d-galactose and l-rhamnose. The major backbone of PPW-1 is primarily comprised of 1,6-linked glucopyranose, every third residue of which is branched at the O-3 position by a side chain consisting of 1,3-linked and terminal glucopyranose. In addition, small amounts of 1,2-linked-α-d-Manp, 1,6-linked-3-O-Me-α-d-Galp and rhamnose exist in PPW-1. In summary, PPW-1 is a novel heteropolysaccharide with potent in vitro hypoglycemic activity, and it may be a potential dietary component for improving glucose homeostasis.

Recent advances in marine algae oligosaccharides: structure, analysis, and potential prebiotic activities

Marine algae contain abundant polysaccharides that support a range of health-promoting activities; however, the high molecular weight, high viscosity, and low solubility of marine algae polysaccharides (MAPs) limit their application in food, agriculture and medicine. Thus, as the degradation products of MAPs, marine algae oligosaccharides (MAOs) have drawn increasing attention. Most MAOs are non-digestible by digestive enzyme in the human gastrointestinal tract, but are fermented by bacteria in the gut and converted into short-chain fatty acids (SCFAs). MAOs can selectively enhance the activities of some populations of beneficial bacteria and stimulate a series of prebiotic effects, such as anti-oxidant, anti-diabetic, anti-tumour. However, the exact structures of MAOs and their prebiotic activities are, to a large extent, unexplored. This review summarizes recent advances in the sources, categories, and structure analysis methods of MAOs, emphasizing their effects on gut microbiota and its metabolite SCFAs as well as the resulting range of probiotic activities.

A comparative analysis of the essential oils from two species of garlic seedlings cultivated in China: chemical profile and anticoagulant potential

Garlic seedlings (GS) and blanched garlic seedlings (BGS) are two kinds of common garlic-derived vegetables in China, but little information is available on their bioactive constituents. In this work, chemical profiles and anticoagulant activities of essential oils from GS (EOGS) and BGS (EOBGS) were disclosed and compared for the first time. Sixteen and fourteen volatile compounds were identified in EOGS and EOBGS by GC-MS analysis, and both of them were rich in sulfur-containing compounds, particularly diallyl sulfides accounting for 74.77% and 85.87%, respectively. EOGS and EOBGS exerted anticoagulant activities via intrinsic, extrinsic, and common coagulation pathways as well as by lowering the content of fibrinogen; EOGS exceeded EOBGS in the activation of intrinsic and extrinsic coagulation pathways, while EOBGS outperformed EOGS on the activation of the common coagulation pathway, which was even superior to that of heparin at the same dose. Herein, the results of the present investigation will give a strong clue that EOGS and EOBGS are more likely to lead to a promising way to vegetable-based anticoagulants.

Immunoactive polysaccharides produced by heterotrophic mutant of green microalga Parachlorella kessleri HY1 (Chlorellaceae)

Hot water extract from biomass of heterotrophic mutant green alga Parachlorella kessleri HY1 (Chlorellaceae) was deproteinised, and three polysaccharidic fractions were obtained by preparative chromatography. The low-molecular fraction (1.5 × 10⁴g mol^-1) was defined mainly as branched O-2-β-xylo-(1→3)-β-galactofuranan where xylose is partially methylated at O-4. Two high-molecular fractions (3.05 × 10⁵ and 9.84 × 10⁴g mol^-1) were complex polysaccharides containing α-l-rhamnan and xylogalactofuranan parts in different ratios. The polysaccharides were well soluble in hot water and, upon cooling, tended to self-segregate. Immunomodulatory activities of the obtained fractions were preliminary tested using ELISA, FACS and ImmunoSpot kits. The polysaccharides increased the TNF-α production in melanoma bearing mice with much higher intensity than in healthy mice. This was in agreement with the FACS results on T and B cells indicating their possibly secondary activation by innate immunity cells.

Anticoagulant-active sulfated arabinogalactan from Chaetomorpha linum: Structural characterization and action on coagulation factors

A sulfated polysaccharide from the green alga Chaetomorpha linum, designated CLS4, was isolated by water extraction, anion-exchange and size-exclusion chromatography. Chemical and spectroscopic analyses demonstrated that CLS4 was a sulfated arabinogalactan, which was constituted by (1→6)-β-d-galactopyranose and (1→5)-α-l-arabinofuranose residues with sulfate groups at C-2/ C-3 of (1→5)-α-l-arabinofuranose and C-2/C-4 of (1→6)-β-d-galactopyranose. CLS4 possessed strong anticoagulant activity in vitro or in vivo as evaluated by activated partial thromboplastin time and thrombin time assays. CLS4 largely inhibited the activities of the coagulation factors XII, XI, IX and VIII. CLS4 was a potent thrombin inhibitor mediated by antithrombin III (ATIII) or heparin cofactor II, and it also effectively stimulated the factor Xa inhibition by potentiating ATIII. Moreover, CLS4 had a high thrombolytic activity in vitro as assessed by clot lytic rate assay. The results suggested that CLS4 could be a promising source of anticoagulant agent.

Biological Activities of Rhamnan Sulfate Extract from the Green Algae Monostroma nitidum (Hitoegusa)

Monostroma nitidum is a green single-cell layered algae that grows on the southwest coast of Japan. It is often used for salad ingredients, boiled tsukudani, soups, etc., due to its health benefits. M. nitidum is composed of many cell aggregates, and the various substances that fill the intercellular space are dietary fibers, vitamins, and minerals. Rhamnan sulfate (RS), a sulfated polysaccharide, is main the component of the fiber extracted from M. nitidum. Recently, some biological properties of RS have been demonstrated by in vitro and in vivo studies that probably protect human subjects from viruses and ameliorate vascular dysfunction caused by metabolic disorders, especially lifestyle-related diseases. In this review, we focus on the antithrombotic effects of RS and introduce its antiviral and other biological activities.

Current Trends on Seaweeds: Looking at Chemical Composition, Phytopharmacology, and Cosmetic Applications

Seaweeds have received huge interest in recent years given their promising potentialities. Their antioxidant, anti-inflammatory, antitumor, hypolipemic, and anticoagulant effects are among the most renowned and studied bioactivities so far, and these effects have been increasingly associated with their content and richness in both primary and secondary metabolites. Although primary metabolites have a pivotal importance such as their content in polysaccharides (fucoidans, agars, carragenans, ulvans, alginates, and laminarin), recent data have shown that the content in some secondary metabolites largely determines the effective bioactive potential of seaweeds. Among these secondary metabolites, phenolic compounds feature prominently. The present review provides the most remarkable insights into seaweed research, specifically addressing its chemical composition, phytopharmacology, and cosmetic applications.

A sulfated glucuronorhamnan from the green seaweed Monostroma nitidum: Characteristics of its structure and antiviral activity

A water-soluble polysaccharide from Monostroma nitidum, designated MWS, was isolated using water extraction, anion-exchange and size-exclusion chromatography. MWS was a sulfated glucuronorhamnan consisting of →3)-α-l-Rhap-(1→, →4)-β-d-GlcpA-(1→ and →2)-α-l-Rhap-(1→ units. Sulfate ester groups located at C-4/C-2 of →3)-α-l-Rhap-(1→ and C-4/C-3 of →2)-α-l-Rhap-(1→ units. In in vitro tests, it was proved that MWS possessed broad spectrum against different viruses, especially for enterovirus 71 (EV71) with nearly no toxicity in relation to cell lines used. MWS may largely inhibit EV71 infection before or during viral adsorption through binding to virus particles and block some early steps of virus life cycle by down-regulating host phosphoinositide 3-kinase /protein kinase B signaling pathway. Intramuscular injection of MWS markedly reduced viral titers in EV71-infected mice. The data demonstrated that MWS could have great promising to become an antiviral drug for prevention and therapy of EV71 infection.

Pharmacologic Application Potentials of Sulfated Polysaccharide from Marine Algae

With the advent of exploration in finding new sources for treating different diseases, one possible natural source is from marine algae. Having an array of potential benefits, researchers are interested in the components which comprise one of these activities. This can lead to the isolation of active compounds with biological activities, such as antioxidation of free radicals, anti-inflammation, antiproliferation of cancer cells, and anticoagulant to name a few. One of the compounds that are isolated from marine algae are sulfated polysaccharides (SPs). SPs are complex heterogenous natural polymers with an abundance found in different species of marine algae. Marine algae are known to be one of the most important sources of SPs, and depending on the species, its chemical structure varies. This variety has important physical and chemical components and functions which has gained the attention of researchers as this contributes to the many facets of its pharmacologic activity. In this review, recent pharmacologic application potentials and updates on the use of SPs from marine algae are discussed.

Structure and in vitro hypoglycemic activity of a homogenous polysaccharide purified from Sargassum pallidum

This study aimed at investigating the structure, hypoglycemic activity and the underlying mechanism of a homogeneous polysaccharide (PSP-2) purified from Sargassum pallidum. Structural characterization revealed that PSP-2 with a molecular weight of 144.8 kDa was composed of fucose (21.6%), arabinose (2.5%), galactose (22.4%), glucose (2.2%), xylose (18.8%), mannose (1.2%), glucuronic acid (7.7%) and galacturonic acid (23.6%). The backbone chain of PSP-2 was composed of →1)-β-d-Xylp-(3→, →1,3)-β-l-Fucp-(4→, →1)-α-d-Galp-(6→, and →1)-α-d-GlcpNAc-(2→, and the side chains were composed of →1,3,6)-α-d-Galp-(2→, →3)-β-l-Fucp-(1,4→, β-d-GalpNAc-(1→, and α-d-Manp-(1→. In vitro hypoglycemic assays indicated that PSP-2 could significantly enhance glucose consumption, glycogen synthesis, and pyruvate kinase (PK) and hexokinase (HK) activities of insulin-resistant HepG2 cells. Furthermore, the underlying mechanistic studies revealed that PSP-2 could ameliorate insulin resistance by up-regulating the expression levels of insulin receptor substrate-1 (IRS-1), glycogen synthase (GS), phosphoinositide-3-kinase (PI3K) and glucose transporter-4 (GLUT4). These results suggested that PSP-2 may be a potential candidate for the prevention and treatment of Type 2 diabetes mellitus.

Anticoagulant and Antithrombotic Properties in Vitro and in Vivo of a Novel Sulfated Polysaccharide from Marine Green Alga Monostroma nitidum

Sulfated polysaccharides from marine algae have high potential as promising candidates for marine drug development. In this study, a homogeneous sulfated polysaccharide from the marine green alga Monostroma nitidum, designated MS-1, was isolated using water extraction and anion-exchange and size-exclusion chromatography. Results of chemical and spectroscopic analyses showed that MS-1 mainly consisted of →3)-α-l-Rhap-(1→ and →2)-α-l-Rhap-(1→ residues, with additional branches consisting of 4-linked β-d-xylose, 4-/6-linked d-glucose, terminal β-d-glucuronic acid, and 3-/2-linked α-l-rhamnose. Sulfate ester groups substituted mainly at C-2/C-4 of →3)-α-l-Rhap-(1→ and C-4 of →2)-α-l-Rhap-(1→ residues, slightly at C-2 of terminal β-d-glucuronic residues. MS-1 exhibited strong anticoagulant activity in vitro and in vivo as evaluated by the activated partial thromboplastin time and thrombin time assays, and significantly decreased platelet aggregation. The anticoagulant activity mechanism of MS-1 was mainly attributed to strong potentiation thrombin by heparin cofactor-II, and it also hastened thrombin and coagulation factor Xa inhibitions by potentiating antithrombin-III. MS-1 possessed markedly thrombolytic activity evaluated by plasminogen activator inhibitior-1, fibrin degradation products, and D-dimer levels using rats plasma, and recanalization rate by FeCl₃-induced carotid artery thrombosis in mice. MS-1 exhibited strong antithrombotic activity in vitro and in vivo evaluated by the wet weighs and lengths of thrombus, and thrombus occlusion time by electrically-induced carotid artery thrombosis in rats. These results suggested that MS-1 could be a promising marine drug for prevention and therapy of thromboembolic disease.

Structure and Anti-Tumor Activities of Exopolysaccharides from Alternaria mali Roberts

In this study, an extracellular polysaccharide from Alternaria mali Roberts (AMEP) was extracted, and its structure was characterized, in addition to its antitumor activity in vitro. Neutral polysaccharide AMEP-1 and anionic polysaccharide AMEP-2 were isolated from AMEP, and their monosaccharide compositions consisted of mannose (Man), glucose (Glc), and galactose (Gal) but at different ratios. The linking mode of both AMEP-1 and AMEP-2 is Manp-(1→4) and Glcp-(1→6), and the branched chains are connected to the main chain through O-6. AMEP-2 inhibited the proliferation of BGC-823 cells in a time- and concentration-dependent manner. AMEP-2 also induced the apoptosis of BGC-823 cells, and showed anti-tumor effects by inducing cell cycle arrest in the S phase, reactive oxygen species production, and mitochondrial membrane potential reduction in BGC-823 cells. Therefore, AMEP-2 shows potential for further development as a novel anti-tumor agent.

Anticoagulant Properties of a Green Algal Rhamnan-type Sulfated Polysaccharide and Its Low-molecular-weight Fragments Prepared by Mild Acid Degradation

The active sulfated polysaccharide from seaweed possesses important pharmaceutical and biomedical potential. In the study, Monostroma sulfated polysaccharide (MSP) was obtained from Monostroma angicava, and the low-molecular-weight fragments of MSP (MSP-Fs: MSP-F1–MSP-F6) were prepared by controlled acid degradation. The molecular weights of MSP and MSP-F1–MSP-F6 were 335 kDa, 240 kDa, 90 kDa, 40 kDa, 24 kDa, 12 kDa, and 6.8 kDa, respectively. The polysaccharides were sulfated rhamnans that consisted of →3)-α-l-Rhap-(1→ and →2)-α-l-Rhap-(1→ units with partial sulfation at C-2 of →3)-α-l-Rhap-(1→ and C-3 of →2)-α-l-Rhap-(1→. Anticoagulant properties in vitro of MSP and MSP-F1–MSP-F6 were evaluated by studying the activated partial thromboplastin time, thrombin time, and prothrombin time. Anticoagulant activities in vivo of MSP and MSP-F4 were further evaluated; their fibrin(ogen)olytic activities in vivo and thrombolytic properties in vitro were also assessed by D-dimer, fibrin degradation products, plasminogen activator inhibitior-1, and clot lytic rate assays. The results showed that MSP and MSP-F1–MSP-F4 with molecular weights of 24–240 kDa had strong anticoagulant activities. A decrease in the molecular weight of MSP-Fs was accompanied by a decrease in the anticoagulant activity, and higher anticoagulant activity requires a molecular weight of over 12 kDa. MSP and MSP-F4 possessed strong anticoagulant activities in vivo, as well as high fibrin(ogen)olytic and thrombolytic activities. MSP and MSP-F4 have potential as drug or helpful food supplements for human health.

Structural Characteristics and Anticoagulant Property In Vitro and In Vivo of a Seaweed Sulfated Rhamnan

Great diversity and metabolite complexity of seaweeds offer a unique and exclusive source of renewable drug molecules. Polysaccharide from seaweed has potential as a promising candidate for marine drug development. In the present study, seaweed polysaccharide (SPm) was isolated from Monostroma angicava, the polymeric repeat units and anticoagulant property in vitro and in vivo of SPm were investigated. SPm was a sulfated polysaccharide which was mainly constituted by 3-linked, 2-linked-α-l-rhamnose residues with partially sulfate groups at C-2 of 3-linked α-l-rhamnose residues and C-3 of 2-linked α-l-rhamnose residues. Small amounts of xylose and glucuronic acid exist in the forms of β-d-Xylp(4SO₄)-(1→ and β-d-GlcA-(1→. SPm effectively prolonged clotting time as evaluated by the activated partial thromboplastin time and thrombin time assays, and exhibited strong anticoagulant activity in vitro and in vivo. The fibrin(ogen)olytic and thrombolytic properties of SPm were evaluated by plasminogen activator inhibitior-1, fibrin degradation products, D-dimer and clot lytic rate assays using rats plasma, and the results showed that SPm possessed high fibrin(ogen)olytic and thrombolytic properties. These results suggested that SPm has potential as a novel anticoagulant agent.

A sulfated heterorhamnan with novel structure isolated from the green alga Monostroma angicava

A sulfated polysaccharide, designated MAP2, was isolated from Monostroma angicava by water extraction, anion-exchange and size-exclusion chromatography. The structural characteristics of MAP2 were investigated by chemical and spectroscopic methods, including methylation analysis, one- and two-dimensional nuclear magnetic resonance and electrospray mass spectrometry with collision-induced dissociation spectroscopic analyses. The results showed that MAP2 was primarily composed of rhamnose with small amounts of xylose, glucuronic acid and glucose. The molecular weight of MAP2 was estimated to be about 671 kDa. The backbone of MAP2 was mainly constituted by 3-linked, 2-linked-á-l-rhamnose residues. Sulfate substitutions were at C-2/C-4 of 3-linked-á-l-rhamnose and C-3/C-4 of 2-linked-á-l-rhamnose residues. The branches consisted of 3-linked and 2-linked-á-l-rhamnose with monosulfate/unsulfate, as well as small amounts of β-d-GlcA-(1→ and β-d-GlcA (2SO₄)-(1 → . Minor amounts of →4)-d-Glcp-(1→ and β-d-Xylp (4SO₄)-(1→ might also be existent in MAP2. The investigation demonstrated that MAP2 was a novel sulfated rhamnan distinguishing from other algal sulfated rhamnans.

Physicochemical characterization and in vitro hypoglycemic activities of polysaccharides from Sargassum pallidum by microwave-assisted aqueous two-phase extraction

Microwave-assisted aqueous two-phase extraction (MAATPE) was applied for simultaneous extraction and separation of polysaccharides from Sargassum pallidum (SPPs). The optimal extraction parameters, physicochemical properties, and hypoglycemic activities in vitro of SPPs were investigated. The results revealed that the optimal extraction conditions were as follows: 21.0% ethanol (w/w) and 22.0% ammonium sulfate (w/w) for ATPS, ratio of material to liquid 1:60 (g/mL), extraction time 15 min, microwave power 830 W, and extraction temperature 95 °C. Under the optimal these conditions, the maximum yields of SPPs were 0.75 ± 0.04% of the top phase (SPP-1) and 6.81 ± 0.33% of the bottom phase (SPP-2). SPP-1 and SPP-2 were homogeneous with molecular weights of 1518.6 and 50.6 kDa, respectively. SPP-1 mainly consisted of fucose, galactose, mannose, and glucuronic acid with a molar ratio of 4.97:9.75:6.44:6.07, whereas SPP-2 was mainly composed of fucose, galactose, glucose, and mannose with a molar ratio of 4.20:2.88:18.05:7.83. SPP-1 and SPP-2 exhibited favorable α-amylase and α-glucosidase inhibitory activities, and could remarkably improve glucose consumption in insulin resistance (IR) model cells. Notably, SPP-1 exhibited stronger α-glucosidase inhibitory activity than SPP-2, and even was comparable with acarbose.