An acidic exopolysaccharide α-D-galacturono-ß-D-glucan produced by the cyanobacterium Scytonema sp.

Some cyanobacteria produce a wide range of secondary metabolites, some of which are of industrial interest. Exopolysaccharides, particularly interesting among them, represent relatively complex primary structures with interesting bioactivity, biodegradability and specific applications. Cultivation of the freshwater cyanobacterium Scytonema sp. provided a proteoglycan-type exopolysaccharide with a relatively low yield and a wide spectrum of molecular weights (Mw) ranging from 2.2 to 1313 × 103 g/mol. Chemical analyses detected the presence of carbohydrates (46 wt%), proteins (10 wt%) and uronic acids (8 wt%). Monosaccharide analysis revealed up to seven neutral sugars with a dominance of glucose (23.6 wt%), galactose (7.4 wt%) and fucose (5.0 wt%) residues, while the others had a much lower content (0.9-3.4 wt%). The presence of galacturonic acid (8.0 wt%) indicated the appearance of ionic type of exopolysaccharide. A preliminary structural study indicated that the α-D-galacturono-ß-D-glucan forms a dominant part of Scytonema sp. exopolymer. Its backbone is composed of two 1,6-linked and one 1,2-linked ß-D-Glcp residues, which is branched at O6 by side chains composed of α-D-GalAp(1 â†’ 2)-ß-D-Glcp(1→ dimer or monomeric ß-D-Glcp(1→ residue.

Dendrobium officinale polysaccharides-chemical properties and pharmacodynamic effects on the airways in experimental conditions.

The study aimed to analyze the effects of Dendrobium polysaccharides on the cough and airway reactivity and compare them with the effects of clinically used antitussives (codeine phosphate and butamirate citrate) and bronchodilators (salbutamol), using the guinea pig test system. Dendrobium officinale polysaccharides contained proteins (4.0 wt%) and phenolic compounds (1.7 wt%) with a molecular weight of 25,000 g/mol. The sugar analysis revealed a dominance of glucose (93.7 wt%) and a lesser amount of mannose (5.1 wt%) while other sugar quantities were negligible. Methylation analysis indicated the presence of highly branched polysaccharides. Glucose was found mainly as terminal, 1,4- and 1,6-linked. Furthermore, some 1,4- and 1,6-linked glucose units were found branched at O2, O3, and O6/O4. Mannose was terminal and 1,4-linked. NMR spectra signals indicate the presence of the (1→4)-linked α-d-glucan, (1→4)-linked ß-d-glucan branched at position O6, (1→6)-linked ß-d-glucan branched at position O3 and (1→4)-linked glucomannan. Pharmacological studies showed statistically significant antitussive activity of Dendrobium polysaccharides, exceeding the effect of clinically used antitussives, which may be partially associated with confirmed bronchodilation and the ability of polysaccharides to increase the threshold of cough receptor activation. Dendrobium polysaccharides may increase the possibility of symptomatic treatment of cough, especially in asthmatics.

Water-extractable polysaccharide fraction PNE-P1 from Pinus koraiensis pine nut: Structural features and immunostimulatory activity.

The polysaccharide fraction PNE-P1 was isolated from hot water extract (PNE) of the defatted meal of pine nuts (Pinus koraiensis) using DEAE-cellulose column chromatography. This fraction had three components of molecular masses 1251, 616, and 303 g/mol consisting mainly of arabinose, xylose, and galacturonic acid at a molar ratio of 2:1.6:1. Structural analysis with FTIR/Raman, methylation and GC-MS, and NMR revealed that PNE-P1 is a cell wall polysaccharide complex including arabinan, heteroxylan, homogalacturonan (HM) and rhamnogalacturonan I (RG-I) parts. Being nontoxic to RAW 264.7 macrophages in the concentration range of 10-200 µg/mL, PNE-P1 promoted proliferation of these cells, significantly induced the secretion of proinflammatory cytokines (TNF-α and IL-6) and chemokines (RANTES and MIP-1α) and enhanced the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) and nitric oxide (NO). PNE-P1 also markedly induced macrophage-mediated phagocytosis of apoptotic Jurkat T cells. These results demonstrate that pine nuts Pinus koraiensis contain a complex of water-soluble plant cell wall polysaccharides, which can stimulate innate immunity by potentiating macrophage function.

Structural properties of the biologically active Dictyosphaerium chlorelloides exopolysaccharide α-d-manno-α-l-rhamno-α-d-(2-O-methyl)-galactan.

Structure of biopolymers produced by microalgae plays an important role for their potential biological activity prediction and applications. Previously isolated and well characterized dominant fractions (Dch5-8) from ion-exchange chromatography separation of the biologically active microalga Dictyosphaerium chlorelloides exopolysaccharide (Dch) were pooled and partially acid hydrolyzed. The dominant sugar components in the combined Dch5-8 fraction were Gal and its 2-O-methyl derivative, Rha and Man, all accounting for about 94 mol% of total amount of sugars. Separation of obtained hydrolysate on Bio-Gel P-2 afforded ten fractions. Their main components were identified by NMR. Based on oligosaccharide structures, the repeating unit of the polysaccharide backbone was identified as →2)-α-L-Rhap-(1→4)-2-O-methyl-[3-O-ß-D-Galp]-α-D-Galp-(1→ branched by Man. Furthermore, the higher molecular weight fraction contained glucuronorhamnan. NMR data indicate 1,4-linked Rha units in the backbone in α and ß configuration, branched at O2 by 2,4-di-O-methyl-ß-d-glucuronic acid.

Polysaccharides extracted with hot water from wild Prunus spinosa L. berries.

Wild blackthorn berries represent an unexplored area in terms of the characterization of the natural biologically active polysaccharide complexes they contain. The antioxidant active fraction extracted from wild blackthorn fruits by hot water extraction (Hw) was subjected to ion-exchange chromatography and yielded six fractions by successive elution with salts. The purified fractions differed in the content of neutral sugars, uronic acids, proteins and phenolics. About 62% of the applied material was recovered from the column, with a higher yield of the fractions eluted with 0.25 M NaCl. Based on the sugar composition of the eluted fractions, several polysaccharide types were observed. The dominant components of Hw are the fractions eluted with 0.25 M NaCl (∼70%), which represent highly esterified homogalacturonan, containing up to 70-80% of galacturonic acids with a low content of rhamnogalacturonan associated with arabinan, galactan or arabinogalactan side chains, but no phenolics. Further, a dark brown polysaccharide material with a yield of ∼17% and with a high content of phenolic compounds, was eluted with alkali (1.0 M NaOH). It mainly represents an acidic arabinogalactan.

Structural properties of the extracellular biopolymer (ß-D-xylo-α-D-mannan) produced by the green microalga Gloeocystis vesiculosa Nägeli.

Many species of microalgae produce a relatively diverse range of metabolites that are interesting for biotechnological applications, and among them exopolysaccharides attract attention due to their structural complexity, biological activities, biodegradability or biocompatibility. An exopolysaccharide of high molecular weight (Mp) of 6.8 × 105 g/mol was obtained by cultivation of the freshwater green coccal microalga Gloeocystis vesiculosa Nägeli 1849 (Chlorophyta). Chemical analyses revealed a dominance of Manp (63.4 wt%), Xylp and its 3-O-Me-derivative (22.4 wt%), and Glcp (11.5 wt%) residues. The results of the chemical and NMR analyses showed an alternating branched 1,2- and 1,3-linked α-D-Manp backbone terminated by a single ß-D-Xylp and its 3-O-methyl derivative at O2 of the 1,3-linked α-D-Manp residues. The α-D-Glcp residues were found mainly as 1,4-linked and to a lesser extent as the terminal sugar, indicating partial contamination of ß-D-xylo-α-D-mannan with amylose (∼10 wt%) in G. vesiculosa exopolysaccharide.

An arabinan isolated from the antioxidant active fraction of wild blackthorn fruits (Prunus spinosa L.).

Despite the many health benefits of wild blackthorn fruits, their use is negligible and little explored. Preliminary results suggest that this fruit is a rich source of natural antioxidants. Antioxidant active fraction, extracted from wild blackthorn fruits by cold water extraction (Cw), was subjected to ion-exchange chromatography, which gave ten fractions after a successive elution with water, sodium chloride and sodium hydroxide solutions. Fraction eluted by water contained an arabinan of a low molecular weight (Mw = 5000). Its chemical and spectroscopic studies have revealed a highly branched structure with backbone composed of 1,5-linked α-l-arabinofuranose residues; about 76% of them are branched dominantly through O3 and much less through O2, however, some arabinose units (∼8%) were fully branched. In addition to terminal α-L-Araf, the presence of ß-L-Araf unit was also identified in blackthorn L-arabinan. Antioxidant activity tests of Cw ion exchange fractions revealed significant effects only of fractions eluted with 1 M sodium chloride (6F) and sodium hydroxide (7F) solutions, while phenolic free arabinan did not possess this effect. Phenolic compounds linked via α-l-arabinosyl side chains appear to be responsible for the antioxidant effect of two Cw fractions.

Effectivity of polyphenolic polysaccharide-proteins isolated from medicinal plants as potential cellular immune response modulators.

Traditional medicinal herbs as Echinacea purpurea and Erigeron canadensis are recommended as a complementary supplementation for the treatment of diseases associated with immunological inflammation (e.g. common cold, coughs, bronchitis, upper respiratory infections, immunodeficiencies). This pathologic conditions are accompanied by the wide range of malfunctions or imbalances of the immune system, thus there is increased necessity for search of novel immunomodulation trends and immunopharmacologically active phytosubstances for effective pharmaco-immunomodulatory therapy. Anti-inflammatory immunobiological activity of polyphenolic polysaccharide-proteins of Echinacea purpurea and Erigeron canadensis are still not studied. Our results demonstrated the immunobiological effectivity of selected herbal polyphenolic polysaccharide-proteins isolated from flowers of medicinal plants Echinacea purpurea and Erigeron canadensis resulting into the significant immunostimulation of inflammatory TNF-α, IL-6, IL-1ß and IL-12 cytokines (p < 0.001). Both herbal polyphenolic polysaccharide-proteins triggered cell release of anti-inflammatory interleukin IL-10 (p < 0.001). Furthermore, the inductive cell release of growth factors M-CSF and GM-CSF has been demonstrated (p < 0.001). E. purpurea and E. canadensis polyphenolic polysaccharide-proteins accelerated the efficacy of cellular phagocytosis and free radical release, more pronounced with Erigeron treatment.

Sulfated Glucuronorhamnoxylan from Capsosiphon fulvescens Ameliorates Osteoporotic Bone Resorption via Inhibition of Osteoclastic Cell Differentiation and Function In Vitro and In Vivo.

Excessive osteoclast differentiation and/or bone resorptive function causes a gradual loss of bone, leading to the pathogenesis of bone diseases such as osteoporosis (OP). In this study, a sulfated glucuronorhamnoxylan polysaccharide (designated SPS-CF) of the green alga Capsosiphon fulvescens was evaluated for anti-osteoporotic activity using osteoclastic cells differentiated from RAW264.7 macrophages by receptor activator of NF-κB ligand (RANKL) treatment and ovariectomized (OVX) female mice as a postmenopausal OP model. With negligible cytotoxicity, SPS-CF (50 µg/mL) significantly suppressed tartrate-resistant acid phosphatase (TRAP) activity, actin ring formation, and expression of matrix metalloproteinase 9 (MMP-9), cathepsin K, TRAF6, p-Pyk2, c-Cbl, c-Src, gelsolin, carbonic anhydrase II (CA II), and integrin ß3, indicating that SPS-CF inhibits the differentiation and bone resorptive function of osteoclasts. Removal of sulfate groups from SPS-CF abolished its anti-osteoclastogenic activities, demonstrating that sulfate groups are critical for its activity. Oral administration of SPS-CF (400 mg/kg/day) to OVX mice significantly augmented the bone mineral density (BMD) and serum osteoprotegerin (OPG)/RANKL ratio. These results demonstrated that SPS-CF exerts significant anti-osteoporotic activity by dampening osteoclastogenesis and bone resorption via downregulation of TRAF6-c-Src-Pyk2-c-Cbl-gelsolin signaling and augmentation of serum OPG/RANKL ratios in OVX mice, suggesting that SPS-CF can be a novel anti-osteoporotic compound for treating postmenopausal OP.

Structural features of biologically active extracellular polysaccharide produced by green microalgae Dictyosphaerium chlorelloides.

Ion-exchange chromatography of the biologically active extracellular biopolymer produced by D. chlorelloides yielded ten fractions differing in yield, protein content, monosaccharide composition and molecular weight distribution. Their sugar compositional analyses showed rhamnogalactans, substituted to different extent by mannose and glucose, as a dominant EPS component in all fractions (91 %) except one containing arabinogalactan (7 %). In highly branched rhamnogalactans the quantity of linear (1,3-; 1,4- and 1,6-linked) and branched ß-D-galactose units (1,3,6-, 1,4,6- and 1,3,4,6-linked) was nearly equal. From various α-L-rhamnose linkages the 1,2,4-linkage was dominant. Data indicate a rhamnogalactan backbone of EPS, branched by terminal mannose and glucose units, and a lot of O-methylated derivatives of galactose residues (2-O-methyl, 2,3-O-dimethyl, 3-O-methyl and 6-O-methyl). In individual fractions their content and type varied. Detail study of the arabinogalactan showed that its backbone consists of 1,3-linked ß-D-Galp units; some of them are branched through O-4 by 6-OMe-α-D-Galp- (1 â†’ 2) -α-L-Araf side chain, other through O-6 by 3-OMe-ß-D-Galp, 6-OMe-ß-D-Galp, ß-D-Galp and ß-D-Galf.

Isolation, chemical characterization and antioxidant activity of Prunus spinosa L. fruit phenolic polysaccharide-proteins.

Wild blackthorn fruits are a slightly explored area and their use is negligible, although they show many therapeutic effects. Polysaccharide complexes were solubilized from ripe Prunus spinosa L. fruits by sequential extraction with water (cold and hot), oxalate, ammonia, and sodium hydroxide solutions. The extracted fractions were rich in carbohydrates, phenolics, and proteins, indicating the presence of complexes of these compounds. It was found that most of the material was released with 5% KOH and hot water. The aqueous fractions had a high molecular weight and also polydispersity index, while the other fractions had low molecular weight. Based on the monosaccharide composition, three groups of fractions were observed. The aqueous and oxalate fractions represent highly esterified pectin material, ammonia extraction provided a mixture of de-esterified pectin and hemicelluloses, and alkaline isolates were rich in arabinogalactan and hemicelluloses. Antioxidant activity tests revealed significant effects of blackthorn samples, alkali-extracted fractions at concentrations of 0.02 and 0.05 mg/mL achieved DPPH radical scavenging comparable to that of vitamin C. Most samples achieved maximum activity comparable to vitamin C at a concentration of 0.1 mg/mL. An analogous effect was also found by the FRAP test, all fractions had a significant reducing capacity at a concentration of 0.05 mg/mL, but only the alkaline fractions reached almost vitamin C level. Preliminary results may support interest in these "undiscovered" natural fruits as a rich source of natural antioxidants.

Polysaccharides from Basidiocarps of the Polypore Fungus Ganoderma resinaceum: Isolation and Structure.

In this study, we focused on the isolation and structural characterization of polysaccharides from a basidiocarp of polypore fungus Ganoderma resinaceum. Polysaccharide fractions were obtained by successive extractions with cold water at room temperature (20 °C), hot water under reflux (100 °C), and a solution of 1 mol L-1 sodium hydroxide. The purity of all fractions was controlled mainly by Fourier transform infrared (FTIR) spectroscopy, and their composition and structure were characterized by organic elemental analysis; neutral sugar and methylation analyses by gas chromatography equipped with flame ionization detector (GC/FID) and mass spectrometry detector (GC/MS), respectively; and by correlation nuclear magnetic resonance (NMR) spectroscopy. The aqueous extracts contained two main polysaccharides identified as a branched O-2-ß-d-mannosyl-(1→6)-α-d-galactan and a highly branched (1→3)(1→4)(1→6)-ß-d-glucan. Mannogalactan predominated in the cold water extract, and ß-d-glucan was the main product of the hot water extract. The hot water soluble fraction was further separated by preparative anion exchange chromatography into three sub-fractions; two of them were identified as branched ß-d-glucans with a structure similar to the corresponding polysaccharide of the original fraction. The alkaline extract contained a linear (1→3)-α-d-glucan and a weakly branched (1→3)-ß-d-glucan having terminal ß-d-glucosyl residues attached to O-6 of the backbone. The insoluble part after all extractions was identified as a polysaccharide complex containing chitin and ß-d-glucans.

Chemical characteristics and significant antitussive effect of the Erigeron canadensis polyphenolic polysaccharide-protein complex.

ETHNOPHARMACOLOGICAL RELEVANCE: Erigeron canadensis has been used in traditional medicine to treat a variety of respiratory diseases, including acute upper and lower respiratory tract infections and cough-related asthma. There is as yet no relevant experimental or clinical study in the scientific literature evaluating the efficacy of plants in these disorders. AIM OF THE STUDY: To investigate the active ingredients in Erigeron canadensis, a complex isolated from flowering parts of a plant was tested for airway defense reflexes, in particular for cough reflexes and airway reactivity. Both were experimentally induced by a chemical irritant that simulated the inflammatory conditions of their formation. MATERIAL AND METHODS: The polyphenolic polysaccharide-protein (PPP) complex was isolated from the flowering parts of Erigeron canadensis by hot alkaline extraction and a multi-stage purification process. The antitussive activity was confirmed as a decrease in the number of citric acid-induced coughs and the bronchodilator effect was verified as a decrease in specific airway resistance (sRaw) in conscious guinea pigs. RESULTS: The dark brown Erigeron complex with a molecular weight of 38,000 g/mol contained phenolics (13.2% wt%), proteins (16.3% wt%), and uronic acids (6.3% wt%). The neutral carbohydrate part of Erigeron consisted mainly of xylose (12.1 wt%), glucose (13.3 wt%), arabinose (24.1 wt%), and galactose (41.0 wt%) residues. Arabinogalactan and 4-OMe-glucuronoxylan have been found to be the major polysaccharides in the Erigeron complex. Using a method of chemically-induced cough reflex and guinea pigs test system the Erigeron complex exhibited statistically significant, the dose-dependent antitussive activity, which was similar to that of the centrally-acting opioid agonist codeine. CONCLUSION: Pharmacological tests have revealed a new pharmacodynamic effect of the Erigeron complex, namely an antitussive effect. Its activity was most pronounced in comparison with all previously tested compounds from other medicinal plants and approached the effect of codeine, the most potent antitussive used in clinical practice. The results provide the scientific basis for the application of this herb in traditional medicine.

Lactylated acidic exopolysaccharide produced by the cyanobacterium Nostoc cf. linckia.

Cyanobacteria produce a wide range of metabolites of interest for industrial or medical use. The cultivation of freshwater Nostoc cf. linckia yielded 5.4 g/L of a crude exopolysaccharide (cEPS) with a molecular weight of 1.31 × 105 g/mol. Ion-exchange chromatography of cEPS yielded two dominant fractions, EPS-1 and EPS-2, differing in molecular weight. The lower molecular weight fraction (EPS-1) was subjected to structural studies. Results of chemical and spectroscopic analyses showed that three of the four dominant sugars, glucose, galactose and xylose are 1,4-linked in the backbone in the following order: [→4)-ß-D-Xylp-(1 â†’ 4)-ß-D-Glcp-(1 â†’ 4)-α-D-Galp-(1 â†’ 4)-ß-D-Glcp-(1→]n. Terminal mannose residues were identified as side chains linked at C3 of every third backbone xylose and every second glucose is branched at C6 by 3-O-lactyl-ß-D-glucuronic acid (nosturonic acid). Antioxidant properties of EPS were tested using two in vitro methods. Both assays showed that the cEPS was more active than purified EPS-1 and EPS-2 fractions and deproteinized EPS.

Optimizing acid hydrolysis for monosaccharide compositional analysis of Nostoc cf. linckia acidic exopolysaccharide.

The exact estimation of monosaccharide composition is important in the primary structure elucidation of polysaccharides. An acid hydrolysis is usually performed for glycosidic bonds cleavage and releasing of monosaccharides. In this study, optimal conditions of total acid hydrolysis using trifluoroacetic acid (TFA) of acidic lactylated Nostoc cf. linckia exopolysaccharide (EPS) were investigated by NMR spectroscopy. Results of a series of experiments with modified acid concentration, temperature and time of hydrolysis, have shown 2 M TFA, 110 °C, 3 h as the most optimal. The stability of EPS monosaccharide components was also explored. Low stability was found at all tested conditions already during the first hour of hydrolysis; all neutral monosaccharides were degraded from 25% to 40% and glucuronic acid to 75%. NMR, contrary to standard techniques used in monosaccharide compositional analysis (HPLC, HPAEC), allowed simultaneous quantification of all GlcA forms; the free one, that one linked in oligosaccharides, as well as GlcA degradation product γ-lactone. NMR as detection method improves information about uronic acid content in EPS.

Structural characterization and anti-asthmatic effect of α-l-arabino(4-O-methyl-α-d-glucurono)-ß-d-xylan from the roots of Rudbeckia fulgida.

Many native plant biopolymers or derivatives thereof have interesting biological effects and therefore the search for additional biological activities is important to map their overall effects. A low molecular weight (Mw = 7600 g/mol) hemicellulose polymer α-L-arabino(4-O-methyl-α-D-glucurono)-ß-D-xylan (AGX) was isolated from the crushed roots of the Rudbeckia fulgida medicinal plant by alkaline extractions and anion-exchange chromatography. Analysis of neutral sugars revealed a predominance of xylose (82.3 wt%) and arabinose (6.8 wt%), while other neutral sugars were found only in small amounts as contaminants. The uronic acid content in Rudbeckia AGX was determined to be 8.8 wt%. Pharmacological tests showed that Rudbeckia AGX effectively suppressed cough and the initial amplitude of histamine/methacholine-induced bronchoconstriction in healthy OVA-sensitive guinea pigs. In addition, its effect at a dose of 100 mg/kg was similar to or greater than that of the positive control bronchodilator salbutamol and the antitussive codeine agent. These findings support the fact that Rudbeckia AGX could be a suitable candidate for alternative treatment of allergic asthma.

Optimization of Ultrasound-Assisted Extraction of Functional Food Fiber from Canadian Horseweed (Erigeron canadensis L.).

Much attention has been recently paid to the design of sustainable processes for the production of functional food additives based on renewable resources. Thus, methods for incorporation of green techniques in treatment of undeveloped biomass, resulting in value-added bioproducts, are in great demand. We focus here on the biological activity and chemical properties of Erigeron canadensis (horseweed) functional food fiber, which can be strongly affected by the extraction procedure employed. In the present contribution, we report on an attempt to introduce a sustainable and energy-efficient ultrasound-assisted extraction process, followed by a multistep purification procedure, resulting in a macromolecular plant-derived anticoagulant agent. The most efficient ultrasound-assisted process was determined by optimization through the response surface methodology I-optimal design (24). A comparison with the conventional procedure for retrieval of horseweed biomacromolecules revealed that the optimized ultrasound-assisted extraction was more sustainable, with the cumulative energy demand being 38% lower (12.2 MJ), 6.6 times reduced water consumption (3.5 L), and 1.2 times shorter (41 h) total processing time. Moreover, the optimal ultrasound-assisted extraction process-purified food fiber turned out to be a better anticoagulant agent by 57%, compared to a conventional product, and was a more selective indirect inhibitor of the human Xa coagulation factor.

Structural features of the bioactive cyanobacterium Nostoc sp. exopolysaccharide.

Microalgal biopolymers are studied mainly in terms of physico-chemical characterization, biological effects as well as possible biotechnological applications. Due to the significant antitussive, bronchodilator, anti-inflammatory and immunomodulatory effects of the previously isolated crude extracellular polysaccharide (EPS) produced by the cyanobacterium Nostoc sp., the purified biopolymer and its oligosaccharides, obtained after partial acid hydrolysis, were subjected to an in-depth NMR structural study. Analyses of the data obtained by chemical methods and NMR showed that the EPS backbone is composed of the repeating unit [→4)-ß-D-Xylp-(1 → 4)-ß-D-Glcp-(1 → 4)-α-L-Arap-(1 → 3)-ß-D-Manp-(1→]n, in which about 60% of glucose units are substituted at C6 by uronic acids, in particular by the unusual unsaturated 3-O-lactyl-4-deoxy-α-erythro-hex-4-enopyranuronic acid, and to a lesser extent by ß-D-glucuronic acid and 3-O-lactyl-ß-D-glucuronic acid. These findings, structural features and identified biological effects, suggest the potential use of this biopolymer in the medical-pharmaceutical field.

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-ß-xylo-(1→3)-ß-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.

Chlorella vulgaris α-L-arabino-α-L-rhamno-α,ß-D-galactan structure and mechanisms of its anti-inflammatory and anti-remodelling effects.

Microalgal exopolysaccharides (EPSs) are given great attention due to their potential biotechnology applications. Purified C. vulgaris EPS was subjected to compositional and sugar linkage analyses, and partial acid hydrolysis. Hydrolysate separation by gel chromatography afforded oligosaccharide fractions. Both, EPS and oligomers were studied by NMR spectroscopy. Data suggest very complex highly branched α-L-arabino-α-L-rhamno-α,ß-D-galactan structure. Backbone repeating unit is formed by →2)-α-L-Rha (1 â†’ 3)-α-L-Rha(1 â†’ sequence, highly branched by long 1,6-linked α-D-Galp side chains, further branched at C2, C3 or C4 by α-L-Araf, α-D-Galf and ß-D-Galf residues. α-L-Araf form longer 1,2-linked chains branched at C3, C4 or C5. Galf residues are localized as terminal units predominantly in the ß configuration, while α-D-Galp and α-L-Araf may be partially O-methylated. Ex vivo biological assays showed increased interleukin-12 (IL-12) and interferon-gamma (INF-γ) levels corresponding to transforming growth factor beta (TGF-ß) decrease in guinea pig model experimental asthma. These facts point to the anti-remodelling effect of Chlorella EPS and suggest its possible application in the treatment of asthma and chronic obstructive pulmonary disorder.