The Structure-Activity Relationship between Marine Algae Polysaccharides and Anti-Complement Activity

Bioactive carbohydrate polymers from marine sources as potent nutraceuticals in modulating obesity: a review

The majority of bioactive polysaccharides are present in some marine creatures. These polysaccharides are considered as promising anti-obesity agents, their anti-obesity properties involve a number of mechanisms, including suppression of lipid metabolism and absorption, impact on satiety, and prevention of adipocyte differentiation. Obesity is linked to type 2 diabetes, cardiovascular disease, and other metabolic syndromes. In this review various bioactive polysaccharides like chitin, chitosan, fucosylated chondroitin sulphate, chitooligosaccharides and glycosaminoglycans have been discussed for their anti-obesity effects through various pathways. Critical evaluation of observational studies and intervention trials on obesity, lipid hypertrophy, dyslipidemia, and type 2 diabetes was done with a primary focus on specific marine fauna polysaccharide as a source of seafood that is consumed all over the world. It has been observed that consumption of individual seafood constituents was effective in reducing obesity. Thus, marine derived novel bioactive polysaccharides have potential applications in food and pharmaceutical industries.

Functional properties, structural characteristics, and anti-complementary activities of two degraded polysaccharides from strawberry fruits

Two low-molecular-weight polysaccharides (DPSP50 and DPSP70) were obtained using hydrogen peroxide-vitamin C (H2O2-Vc) treatment at 50 °C and 70 °C, respectively. Both DPSP50 and DPSP70 comprised the same six monosaccharides in different ratios, and their molecular weights (Mws) were 640 kDa and 346 kDa, respectively. Functional properties analyses demonstrated that DPSP50 and DPSP70 each had an excellent water holding capacity, oil absorption capacity, and emulsion properties, as well as shear-thinning characteristics and viscoelastic properties. Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopic assays confirmed the existence of α-, β-pyranose rings and the same six sugar residues in DPSP50 and DPSP70. The results of Congo red test, scanning electron microscopy (SEM), and X-ray diffraction (XRD) demonstrated that DPSP50 and DPSP70 did not contain triple-helix conformations, but were amorphous aggregates with flake-like shape and rough surface. Additionally, both DPSP50 and DPSP70 showed strong anti-complementary activities through the classical pathway and the alternative pathway. The results support the potential utility of these degraded polysaccharides from strawberry fruits in functional foods and medicines.

Fucoidans inhibited tau interaction and cellular uptake

Tau spreading in Alzheimer's disease is mediated by cell surface heparan sulfate (HS). As a class of sulfated polysaccharides, fucoidans might compete with HS to bind tau, resulting in the cessation of tau spreading. The structural determinants of fucoidans for competition with HS binding to tau are not well understood. Sixty previously prepared fucoidans/glycans with different structural determinants were used to determine their binding abilities to tau using SPR and AlphaLISA. Finally, it was found that fucoidans had two fractions (sulfated galactofucan (SJ-I) and sulfated heteropolysaccharide (SJ-GX-3)), which exhibited strong binding abilities than heparin. Tau cellular uptake assays using wild type mouse lung endothelial cell lines were performed. It was shown SJ-I and SJ-GX-3 inhibited tau-cell interaction and tau cellular uptake, suggesting that fucoidans might be good candidates for inhibiting tau spreading. NMR titration mapped fucoidans binding sites, which could provide the theoretical basis for the design of tau spreading inhibitors.

Interactions of marine sulfated glycans with antithrombin and platelet factor 4

The molecular interactions of sulfated glycans, such as heparin, with antithrombin (AT) and platelet factor 4 (PF4) are essential for certain biological events such as anticoagulation and heparin induced thrombocytopenia (HIT). In this study, a library including 84 sulfated glycans (polymers and oligomers) extracted from marine algae along with several animal-originated polysaccharides were subjected to a structure-activity relationship (SAR) study regarding their specific molecular interactions with AT and PF4 using surface plasmon resonance. In this SAR study, multiple characteristics were considered including different algal species, different methods of extraction, molecular weight, monosaccharide composition, sulfate content and pattern and branching vs. linear chains. These factors were found to influence the binding affinity of the studied glycans with AT. Many polysaccharides showed stronger binding than the low molecular weight heparin (e.g., enoxaparin). Fourteen polysaccharides with strong AT-binding affinities were selected to further investigate their binding affinity with PF4. Eleven of these polysaccharides showed strong binding to PF4. It was observed that the types of monosaccharides, molecular weight and branching are not very essential particularly when these polysaccharides are oversulfated. The sulfation levels and sulfation patterns are, on the other hand, the primary contribution to strong AT and PF4 interaction.

Isolation, characterization and anticomplementary activity of polysaccharides from the rhizomes of Belamcanda chinensis (L.) DC

The polysaccharides from the rhizomes of Belamcanda chinensis (L.) DC. (BCPs) were obtained by optimal water extraction (extraction temperature 84℃, liquid to solid ratio 42 mL/g and extraction time 100 min), the extraction yield of BCPs was 23.01 ± 0.27% (n=3). Furthermore, two novel polysaccharides (BCP-A1 and BCP-B1) were purified by column chromatography. The BCP-A1 (6.0820×104 kDa) was composed of β -D-Manp-(1→, β -D-Glcp-(1→, →4)-α-D-Galp-(1→ and →3,4)- β-D-Galp-(1→, and BCP-B1 (2.2744×104 kDa) was composed of →5)-α-L-Araf -(1→, β -D-Manp-(1→, β-D-Glcp-(1→, →4)-α-D-Glcp, →4)-α-D-Galp-(1→, →4)-α-D-Galp A-(1→ and →3,4)-β-D-Galp-(1→. In anticomplementary experiments, BCP-A1 (CH50: 0.009 ± 0.003 mg/mL; AP50: 0.015 ± 0.003 mg/mL) and BCP-B1 (CH50: 0.004 ± 0.001 mg/mL; AP50: 0.028 ± 0.005 mg/mL) exhibited potent anticomplementary activity, and acted on C2-, C4- and Factor B components. Our study provides a foundation for BCP-A1 and BCP-B1 as potential complement inhibitors to treat diseases involving with excessive activation of the complement system.

Sulfated Galactofucans: An Outstanding Class of Fucoidans with Promising Bioactivities

Fucoidans encompass versatile and heterogeneous sulfated biopolysaccharides of marine origin, specifically brown algae and marine invertebrates. Their chemistry and bioactivities have been extensively investigated in the last few decades. The reported studies revealed diverse chemical skeletons in which l-fucose is the main sugar monomer. However, other sugars, i.e., galactose, mannose, etc., have been identified to be interspersed, forming several heteropolymers, including galactofucans/fucogalactans (G-fucoidans). Particularly, sulfated galactofucans are associated with rich chemistry contributing to more promising bioactivities than fucans and other marine polysaccharides. The previous reports in the last 20 years showed that G-fucoidans derived from Undaria pinnatifida were the most studied; 21 bioactivities were investigated, especially antitumor and antiviral activities, and unique biomedical applications compared to other marine polysaccharides were demonstrated. Hence, the current article specifically reviews the biogenic sources, chemistry, and outstanding bioactivities of G-fucoidans providing the opportunity to discover novel drug candidates.

Advance research in biomedical applications on marine sulfated polysaccharide

Marine ecosystem associated organisms are an affluent source of bioactive compounds. Polysaccharides with unique structural and practical entities have gained special studies interest inside the current biomedical zone. Polysaccharides are the main components of marine algae, plants, animals, insects, and microorganisms. In recent times research on seaweed is more persistent for extraction of natural bioactive "Sulfated polysaccharides" (SPs). The considerable amount of SP exists in the algae in the form of fucans, fucoidans, carrageenans, ulvan, etc. Major function of SPs is to act as a defensive lattice towards the infective organism. All SPs possess the high potential and possess a broad range of therapeutic applications as antitumor, immunomodulatory, vaccine adjuvant, anti-inflammatory, anticoagulant, antiviral, antiprotozoal, antimicrobial, antilipemic, therapy of regenerative medicine, also in drug delivery and tissue engineering application. This review aims to discuss the biomedicine applications of sulfated polysaccharides from marine seaweeds.

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

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

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

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

Salt-Tolerant Metabolomics for Exometabolomic Measurements of Marine Bacterial Isolates

Identifying and quantifying metabolites secreted by microbial isolates can aid in understanding the physiological traits of diverse species and their interaction with the environment. Mass spectrometry-based metabolomics has potential to provide a holistic view of the exometabolism of marine isolates, but the high salt content of such samples interferes with chromatography and ionization during the measurement of polar exometabolites. The most common desalting methods are faced with major limitations, including limited separation of small polar metabolites from salts, the use of organic solvents that cannot accommodate large salt quantities, and sample throughput. Here, we utilize a cyano stationary phase to develop a high-throughput, isocratic liquid chromatography-mass spectrometry (LC-MS) desalting method that mitigates these shortcomings. We demonstrate that counterions present in a common marine growth medium experience distinct elution times, which prevents their coelution with 73 physiologically relevant polar metabolites, effectively minimizing the effects of salt content on ion suppression. We determined optimal salt concentrations for quadrupole time-of-flight (QTOF) MS measurements and limits of quantification in the low micromolar range in the salty matrix. The efficacy of this method was demonstrated through the measurement of exometabolites secreted by three marine bacterial isolates originating from a carrageenan degrading microbial community. This method provides a simple, versatile desalting method for measuring exometabolites of environmental isolates and other biological matrices.

The structure-activity relationship of the interactions of SARS-CoV-2 spike glycoproteins with glucuronomannan and sulfated galactofucan from Saccharina japonica

The SARS-CoV-2 spike glycoproteins (SGPs) and human angiotensin converting enzyme 2 (ACE2) are the two key targets for the prevention and treatment of COVID-19. Host cell surface heparan sulfate (HS) is believed to interact with SARS-CoV-2 SGPs to facilitate host cell entry. In the current study, a series of polysaccharides from Saccharina japonica were prepared to investigate the structure-activity relationship on the binding abilities of polysaccharides (oligosaccharides) to pseudotype particles, including SARS-CoV-2 SGPs, and ACE2 using surface plasmon resonance. Sulfated galactofucan (SJ-D-S-H) and glucuronomannan (Gn) displayed strongly inhibited interaction between SARS-CoV-2 SGPs and heparin while showing negligible inhibition of the interaction between SARS-CoV-2 SGPs and ACE2. The IC50 values of SJ-D-S-H and Gn in blocking heparin SGP binding were 27 and 231 nM, respectively. NMR analysis showed that the structure of SJ-D-S-H featured with a backbone of 1, 3-linked α-L-Fucp residues sulfated at C4 and C2/C4 and 1, 3-linked α-L-Fucp residues sulfated at C4 and branched with 1, 6-linked β-D-galacto-biose; Gn had a backbone of alternating 1, 4-linked β-D-GlcAp residues and 1, 2-linked α-D-Manp residues. The sulfated galactofucan and glucuronomannan showed strong binding ability to SARS-CoV-2 SGPs, suggesting that these polysaccharides might be good candidates for preventing and/or treating SARS-CoV-2.

Interactions of fibroblast growth factors with sulfated galactofucan from Saccharina japonica

A total 68 types of marine algae oligosaccharides and polysaccharides were prepared and used to study the structure-activity relationship of oligosaccharides and polysaccharides in their interactions with fibroblast growth factors (FGF) 1 and 2. Factors considered include different types of algae, extraction methods, molecular weight, sulfate content and fractions. In the case of low molecular weight polysaccharide (SJ-D) from Saccharina japonica and its fractions eluting from anion exchange column, both 1.0 M NaCl fraction (SJ-D-I) and 2.0 M NaCl fraction (SJ-D-S) had stronger binding affinity than the parent SJ-D, suggesting that sulfated galactofucans represented the major tight binding component. Nuclear magnetic resonance showed that SJ-D-I was a typical sulfated galactofucan, composed of four units: 1, 3-linked 4-sulfated α-L-fucose (Fuc); 1, 3-linked 2, 4-disulfated α-L-Fuc; 1, 6-linked 4-sulfated β-D-Gal and/or 1, 6-linked 3, 4-sulfated β-D-Gal. Modification by autohydrolysis to oligosaccharides and desulfation decreased the FGF binding affinity while oversulfation increased the affinity. The solution-based affinities of SJ-D-I to FGF1 and FGF2 were 69 nM and 3.9 nM, suggesting that SJ-D-I showed better preferentially binding to FGF1 than a natural ligand, heparin, suggesting that sulfated galactofucan might represent a good regulator of FGF1.

Structural characteristics and anti-complement activities of polysaccharides from Sargassum hemiphyllum

Three polysaccharides (SH-1, SH-2 and SH-3) were purified from a brown macroalgea, Sargassum hemiphyllum. The autohydrolysis products from each polysaccharide were separated to three fractions (S fractions as oligomers, L fractions as low molecular weight polysaccharides and H fractions as high molecular weight polysaccharides). Mass spectroscopy of S fractions (SH-1-S, SH-2-S and SH-3-S) showed that these three polymers all contained short stretches of sulfated fucose. The structures of L fractions (SH-1-L, SH-2-L and SH-3-L) were determined by nuclear magnetic resonance (NMR). SH-1-L was composed of two units, unit A (sulfated galactofucan) and unit B (sulfated xylo-glucuronomannan). Unit A contained a backbone of (1, 6-linked β-D-Gal) n1, (1, 3-linked 4-sulfated α-L-Fuc) n2, (1, 3-linked 2, 4-di-sulfated α-L-Fuc) n3, (1, 4-linked α-L-Fuc) n4 and (1, 3-linked β-D-Gal) n5, accompanied by some branches, such as sulfated fuco-oligomers, sulfated galacto-oligomers or sulfated galacto-fuco-oligomers. And unit B consisted of alternating 1, 4-linked β-D-glucuronic acid (GlcA) and 1, 2-linked α-D-mannose (Man) with the Man residues randomly sulfated at C6 or branched with xylose (Xyl) at C3. Both SH-2-L and SH-3-L were composed of unit A and their difference was attributed to the ratio of n1: n2: n3: n4: n5. Based on monosaccharide analysis, we hypothesize that both SH-1-H and SH-2-H contained unit A and unit B while SH-3-H had a structure similar to SH-3-L. An assessment of anti-complement activities showed that the sulfated galactofucan had higher activities than sulfated galacto-fuco-xylo-glucuronomannan. These results suggest that the sulfated galactofucans might be a good candidate for anti-complement drugs.

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.

Resource, chemical structure and activity of natural polysaccharides against alcoholic liver damages

Many natural polysaccharides from bio-resources hold advantages of multi-functions, high efficiency, non-toxicity or low side effect, and have strong potentials in protection against alcoholic liver damages. This review summarized the bio-resources, chemical and structural characteristics of natural polysaccharides with potentials in inhibition against alcoholic liver damages, and also emphasized knowledge on correlations between their chemical structure and function. Approximately 95 species were confirmed in generation of hepatoprotective polysaccharides. Products as crude polysaccharides originated from 17 species were sum up despite the indetermination of their accurate structure. Additional four polysaccharides were described for their known chemical structures. Possible roles of hepatoprotective polysaccharides were provided with evidence on antioxidant promotion, lipids regulation, apoptosis inhibition and anti-inflammation, as well as confirmations in immune enhancement, iron removal and anti-fibrosis when currently treated against the alcoholic liver damages. To sum up, this overview could serve to guide development and utilization of natural hepatoprotective polysaccharides.

Analysis of the complete genome sequence of a marine-derived strain Streptomyces sp. S063 CGMCC 14582 reveals its biosynthetic potential to produce novel anti-complement agents and peptides

Genome sequences of marine streptomycetes are valuable for the discovery of useful enzymes and bioactive compounds by genome mining. However, publicly available complete genome sequences of marine streptomycetes are still limited. Here, we present the complete genome sequence of a marine streptomycete Streptomyces sp. S063 CGMCC 14582. Species delineation based on the pairwise digital DNA-DNA hybridization and genome comparison ANI (average nucleotide identity) value showed that Streptomyces sp. S063 CGMCC 14582 possesses a unique genome that is clearly different from all of the other available genomes. Bioactivity tests showed that Streptomyces sp. S063 CGMCC 14582 produces metabolites with anti-complement activities, which are useful for treatment of numerous diseases that arise from inappropriate activation of the human complement system. Analysis of the genome reveals no biosynthetic gene cluster (BGC) which shows even low similarity to that of the known anti-complement agents was detected in the genome, indicating that Streptomyces sp. S063 CGMCC 14582 may produce novel anti-complement agents of microbial origin. Four BGCs which are potentially involved in biosynthesis of non-ribosomal peptides were disrupted, but no decrease of anti-complement activities was observed, suggesting that these four BGCs are not involved in biosynthesis of the anti-complement agents. In addition, LC-MS/MS analysis and subsequent alignment through the Global Natural Products Social Molecular Networking (GNPS) platform led to the detection of novel peptides produced by the strain. Streptomyces sp. S063 CGMCC 14582 grows rapidly and is salt tolerant, which benefits efficient secondary metabolite production via seawater-based fermentation. Our results indicate that Streptomyces sp. S063 has great potential to produce novel bioactive compounds, and also is a good host for heterologous production of useful secondary metabolites for drug discovery.

Structural Features of Sulfated Glucuronomannan Oligosaccharides and Their Antioxidant Activity

Glucuronomannan oligosaccharides (Gs) were derived from fucoidan, which was extracted from the brown alga Sargassum thunbergii. Sulfated glucuronomannan oligosaccharides (SGs) were obtained by the sulfation of Gs. NMR techniques were used to reveal that the order of sulfation was Man-C6 > Man-C4 > Man-C1R > GlcA-C3 > Man-C3 > GlcA-C2. Finally, the antioxidant activities (hydroxyl radical scavenging activity, superoxide radical scavenging activity, reducing power and DPPH radical scavenging activity) of Gs and SGs were determined. The findings showed that the higher the degree of polymerization, the better the activity, except for the hydroxyl radical scavenging activity. In addition, the higher the sulfate content, the lower the activities for the reducing power and DPPH radical scavenging activity. Opposite results were found for the superoxide radical scavenging activity. Finally, compared with fucoidan, most Gs and SGs had higher antioxidant activity, suggesting that they might be good candidates for antioxidants.

The Sulfated Polysaccharides of Brown Algae and Products of Their Enzymatic Transformation as Potential Vaccine Adjuvants

The review is devoted to critical analysis of literature data, deal with effects and mechanisms of action of sulfated polysaccharides (PSs) – fucoidans from brown algae and products of their enzymatic transformation as potential adjuvants for enhancement of anti-infective and antitumor immune response. Numerous experimental data indicate that sulfated PSs demonstrate properties of vaccine adjuvants. Application perspectiveness of fucoidans as vaccine adjuvants is defined by their high biocompatibility, low-toxicity, safety and good tolerance by macroorganism, and also mechanisms of their immunomodulatory action. In particular, fucoidans are agonists of receptors of innate immunity and strong inducers of cellular and humoral immune response. At presenting the data of structural - functional interrelations, attention focused to the defining role of degree of sulfation, uronic acids and polyphenols contents, and also molecular mass in actions of fucoidans to innate and adaptive immunity cells. Insufficiency of literary data on studying of correlation of structure – physicochemical characteristics with adjuvanticities of the sulfated PSs, and also the problem of standardization of their active fractions are noted. Special attention is paid to the analysis of immunomodulatory and adjuvant activity of fucoidan oligosaccharides. Presented here results of experimental trial indicate that, despite the difficulties due to preparation of highly purified structurally characterized fractions and complex structure of fucoidans, these substances can be used as safe and effective adjuvants in vaccines against various pathogens including viruses, and also in antitumor vaccines.

Genome Mining of the Marine Actinomycete Streptomyces sp. DUT11 and Discovery of Tunicamycins as Anti-complement Agents

Marine actinobacteria are potential producers of various secondary metabolites with diverse bioactivities. Among various bioactive compounds, anti-complement agents have received great interest for drug discovery to treat numerous diseases caused by inappropriate activation of the human complement system. However, marine streptomycetes producing anti-complement agents are still poorly explored. In this study, a marine-derived strain Streptomyces sp. DUT11 showing superior anti-complement activity was focused, and its genome sequence was analyzed. Gene clusters showing high similarities to that of tunicamycin and nonactin were identified, and their corresponding metabolites were also detected. Subsequently, tunicamycin I, V, and VII were isolated from Streptomyces sp. DUT11. Anti-complement assay showed that tunicamycin I, V, VII inhibited complement activation through the classic pathway, whereas no anti-complement activity of nonactin was detected. This is the first time that tunicamycins are reported to have such activity. In addition, genome analysis indicates that Streptomyces sp. DUT11 has the potential to produce novel lassopeptides and lantibiotics. These results suggest that marine Streptomyces are rich sources of anti-complement agents for drug discovery.

Size-dependent pharmacological activities of differently degraded fucoidan fractions from Fucus vesiculosus

Fucose-containing sulfated glycans (syn. fucoidans) from brown algae exhibit a wide range of bioactivities and are therefore considered promising candidates for health-supporting and medical applications. In this study, we investigated the pharmacological activities of fucoidan from Fucus vesiculosus and 18 gradually depolymerized fractions, which were obtained by hydrothermal and H2O2 treatment, respectively. All the activities decreased with decreasing molecular mass (Mw) but to a different extent resulting in some modified pharmacological profiles in dependence on the Mw as well as on the degradation method. H2O2 treatment was not only more efficient, simpler and cheaper than hydrothermal degradation, but also led to superior activity profiles and additionally eliminated co-extracted contaminants. Compared to heparin, the prime example of biologically active sulfated glycans, evenly sized H2O2 fractions exhibited considerable effects being relevant for anti-inflammatory activity, however only negligible anticoagulant activity and FXII activating potency. Due to their improved biopharmaceutical characteristics and favorable activities, degraded fucoidan fractions are worth to be further investigated as anti-inflammatory and anticomplementary agents.

Melanoma and brown seaweed: an integrative hypothesis

Although relatively rare, melanoma accounts for 2 % of cancer diagnoses globally and accounts for about 1 % of all cancer deaths. Worldwide, the annual incidence of melanoma is 272,000 cases which vary hugely, ranging from Japan where it is incredibly infrequent, to Queensland, Australia, where it is nearly 100 times higher. Based on epidemiology and laboratory studies, there is compelling evidence suggesting that seaweed might be protective against different types of cancers such as breast cancer in seaweed consuming populations. By comparing countries where melanoma is more common with countries where it is infrequent, it is possible to construct a hypothesis for how consuming brown seaweeds which may hold clues to the differences in melanoma susceptibility between Japanese and Western nations. Unlike in these other countries, where melanoma incidence has increased dramatically over the last two decades, in Japan, rates have remained remarkably low and stable. There is limited evidence from clinical studies and animal models that have used whole seaweed or isolated fractions from seaweed and measured changes in biomarkers. They have demonstrated the effectiveness of seaweed at inhibiting melanoma development and progression. In this review, the various results will be described. Although there are several effective fractions, it is proposed that consuming whole seaweeds may hold additional benefits that could be lost by consuming only a single extract.

Structure characterization of two novel polysaccharides isolated from the spikes of Prunella vulgaris and their anticomplement activities

ETHNOPHARMACOLOGICAL RELEVANCE

The spikes of Prunella vulgaris have long been used as a traditional Chinese medicine to treat various inflammation-related diseases. The aim of this study was to isolate and characterize homogenous polysaccharides from this herb and to evaluate their anticomplement activity.

MATERIALS AND METHODS

Anticomplement activity-guided fractionation of the hot water extract of P. vulgaris was performed by DEAE-cellulose and size-exclusion chromatography, yielding two homogeneous polysaccharides PW-PS1 and PW-PS2. The homogeneity, molecular weight, monosaccharide composition and linkage of the two polysaccharides were determined in addition to other chemical characterizations. The anticomplement activity of the polysaccharides was evaluated and expressed as 50% hemolytic inhibition concentration through the classical pathway (CH₅₀ value) and alternative pathway (AP₅₀ value). The preliminary mechanism for the complement activation cascade was also assessed.

RESULTS

PW-PS1 and PW-PS2 were both branched acidic polysaccharides. PW-PS1 was composed of Ara, Xyl, and 4-methoxy-Glc A in a ratio of 1.0: 2.6: 0.8. The main linkages of the sugar residues of PW-PS1 included terminal β-d-Xylp, 1,4-linked β-d-Xylp, 1,3-linked α-d-Arap, 1,3,5-linked α-d-Arap, and terminal 4-methoxy-α-d-Glcp A. PW-PS2 was composed of Rha, Ara, Xyl, Gal, and Gal A in a ratio of 0.6: 1.0: 1.3: 1.8: 3.4. The main linkages between the sugar residues of PW-PS2 included terminal Araf, 1,4-linked β-d-Xylp, 1,3-linked α-d-Rhap, terminal α-d-Galp, and 1,4,6-linked α-d-Galp. PW-PS1 and PW-PS2 inhibited complement activation through both the classical and alternative pathways with CH₅₀ values of 0.28 and 0.13mg/mL, respectively, and AP₅₀ values of 0.40 and 0.35mg/mL, respectively. Preliminary mechanism studies using complement component-depleted sera showed that PW-PS1 acted on the C1q, C3, and C9 components and that PW-PS2 acted on the C1q, C2, C3, C5, and C9 components.

CONCLUSION

Our study suggested that PW-PS1 and PW-PS2 could be valuable for the treatment of diseases associated with the excessive activation of the complement system.