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Branched architecture of fucoidans (sulfated fucose-rich polysaccharides) gained considerable interest in recent years in view of the effect of this branching on fucoidan’s biological activity. The aim of this work was to characterize the branching architecture of the pristine and hydrolyzed fucoidan macromolecules of the marine seaweed Fucus vesiculosus. We studied the influence of the duration of acidic hydrolysis on the fucoidan macromolecules. The structure-sensitive ratios of macromolecular radii, obtained by dynamic and static (SLS) light scattering, and capillary viscometry corresponded to spherical form of the macromolecules, indicating their branched architecture. The structure-sensitive ratios were analyzed with respect to the molecular weight distributions obtained by size-exclusion chromatography. The Kratky representation of the angular dependences of SLS intensity provided a spectacular evidence for the fucoidans’ branching. For the first time, the fucoidans’ branching was characterized quantitatively by fitting the scattering form factor developed for hyperbranched macromolecules. Under acidic hydrolysis, the molecular mass and size of the fucoidan macromolecules decreased, but the globular form of macromolecules remained unchanged. Upon increasing the time of the acidic hydrolysis, the ζ-potential of the fucoidans changed from − 14 to − 27 mV. The hydrolyzed fucoidans, in turn, exhibited pronounced polyelectrolyte expansion in aqueous solutions when compared with the unhydrolyzed one.

Simple Summary The continuous emergence of new pathogenic strains of bacteria resistant to antibiotics highlights the importance of search for the new natural sources of antimicrobial compounds. Fucoidans, sulfated polysaccharides from the cell walls of brown algae, attract the attention of many researchers due to their wide range of biological activities. Being natural and practically non-toxic, they are considered as a promising antimicrobial component that could, where possible, replace the use of strong chemical antiseptics and modern antibiotics. Natural fucoidans are polydisperse polysaccharides whose composition can vary greatly depending on the species, habitat, as well as on the way of purification. In this work, we investigate the structure and antibacterial properties of fucoidans from the brown algae Fucus vesiculosus gathered in the littoral of the Barents Sea. These fucoidans appear to have a significant bacteriostatic effect on the growth of four tested bacterial strains. Such an effect was more pronounced for crude fucoidan samples that did not undergo additional steps of purification. Abstract Fucoidans, sulfated polysaccharides found in cell walls of brown algae, are considered as a promising antimicrobial component for various applications in medicine and the food industry. In this study, we compare the antibacterial properties of two fractions of fucoidan from the brown algae Fucus vesiculosus gathered in the littoral of the Barents Sea and sampled at different stages of purification. The crude fraction of fucoidan was isolated from algae by extraction with aqueous ethanol and sonication. The purified fraction was obtained by additional treatment of the crude fraction with a solution of calcium chloride. The structural features of both fractions were characterized in detail and their antibacterial effects against several Gram-positive and Gram-negative bacteria were compared by photometry, acridine orange staining assay, and atomic force microscopy. Fucoidan inhibited growth in all of the above microorganisms, showing a bacteriostatic effect with minimum inhibitory concentrations (MIC) in the range between 4 and 6 mg/mL, with E. coli being the most sensitive to both fractions. Changes in the chemical composition after treatment of the crude fraction with a solution of calcium chloride led to a decrease in the content of sulfates and uronic acids and diminished antibacterial activity.

Two fractions of fucoidans were identified and characterized, and their effects on bacteria were investigated. The values of the minimum inhibitory concentration (MIC) were determined, and the effect on the formation of biofilms was studied.

The aim of this study was to compare the effects of sulfated fucopolysaccharides isolated from Fucus vesiculosus on HeLa G-63, Hep G2, and Chang liver cells. Native fucoidan F3 and two fractions (F3-0.5 and F3-1) obtained by anion-exchange chromatography were analyzed using chemical methods and IR spectroscopy. It was demonstrated that F3 and F3-1 are characterized by a higher content of sulfates, location of sulfo groups mostly at the C4 atom of fucose residue, and low content of uronic acids inhibited cell proliferation. Human liver carcinoma Hep G2 appeared to be the most sensitive to fucoidan, whereas nonmalignant human Chang liver cells were the least sensitive.

The aim of the present study was to compare the effect of sulfated fucopolysaccharides isolated from Fucus vesiculosus on cell lines HeLa G-63, Hep G2 and Chang liver. Native fucoidan F3 and two fractions (F3-0.5 and F3-1), obtained by anion-exchange chromatography, were analyzed using chemical methods and IR-spectroscopy. Their action on cells demonstrates that F3 and F3-1, characterized by higher content of sulfates, preferable location of sulfo-groups at C4 atom of fucose residue and low content of uronic acids, inhibit cell proliferation more efficiently. Human liver tumor cells Hep G2 appeared to be the most sensitive to fucoidan treatment whereas nonmalignant human cells Chang liver were the least sensitive.

The effect of polydisperse fucoidans from brown algae Fucus vesiculosus on Hep G2 and Chang liver cells was studied. Despite the high molecular weight and polydispersity, these fucoidans exhibited antitumor activity, whereas the difference in the inhibitory effects on cell proliferation between the native and the partially hydrolyzed fucoidans was not statistically significant. Fucoidans were internalized by cells of both cell lines through endocytosis, with Chang liver cells metabolizing fucopolysaccharides more rapidly compared to the Hep G2. In both cell lines treatment with fucoidans was shown to induce apoptosis and autophagy, with apoptosis more pronounced in Hep G2 cells, whereas autophagy - in Chang liver cells.

Enzymes capable of modifying the sulfated polymeric molecule of fucoidan are mainly produced by different groups of marine organisms: invertebrates, bacteria, and also some fungi. We have discovered and identified a new strain of filamentous fungus Fusarium proliferatum LE1 (deposition number in Russian Collection of Agricultural Microorganisms is RCAM02409), which is a potential producer of fucoidan-degrading enzymes. The strain LE1 (RCAM02409) was identified on the basis of morphological characteristics and analysis of ITS sequences of ribosomal DNA. During submerged cultivation of F. proliferatum LE1 in the nutrient medium containing natural fucoidan sources (the mixture of brown algae Laminaria digitata and Fucus vesiculosus), enzymic activities of α-L-fucosidase and arylsulfatase were inducible. These enzymes hydrolyzed model substrates, para-nitrophenyl α-L-fucopyranoside and para-nitrophenyl sulfate, respectively. However, the α-L-fucosidase is appeared to be a secreted enzyme while the arylsulfatase was an intracellular one. No detectable fucoidanase activity was found during F. proliferatum LE1 growth in submerged culture or in a static one. Comparative screening for fucoidanase/arylsulfatase/α-L-fucosidase activities among several related Fusarium strains showed a uniqueness of F. proliferatum LE1 to produce arylsulfatase and α-L-fucosidase enzymes. Apart them, the strain was shown to produce other glycoside hydrolyses.

The aim of the research was to investigate cytotoxicity of fucoidans on mammals cells. Three different samples of fucoidans were isolated from mechanically grounded brown algae Laminaria digitata and Fucus ve- siculosus. The sample F2 that differed from the others by higher sulfatation level and suppression of HeLa G-63 line culture growth was taken for further study in cell lines HeLa G-63, ECV 304 and PC 12. We have shown that fucoidan preparation F2 inhibits proliferation and induces cell death in a dose- and time-dependent manner for all investigated cell lines. Neuroendocrine tumor rat cell line PC 12 appeared to be the most sensitive to fucoidan treatment whereas endothelial human cells ECV 304 were the least sensitive.

All isomers of (aminomethyl)furancarboxylic acids were prepared by the Delepine reaction from alkyl (halomethyl)furancarboxylates. Treatment of the initially formed quaternary salt with an ethanolic HCl solution yielded the salts of the corresponding unstable amino acid esters. A procedure for their purification to a high degree of purity was developed. Hydrolysis of the crude esters yielded stable amino acid salts.

Acylation of aromatic amino acids with furancarboxylic acid chlorides effectively proceeds in water-acetone medium at pH 8-9. Aliphatic amino acids are acylated at higher pH values, but under these conditions hydrolysis of acid chlorides becomes the main process. Acylation of chlorohydrates of methyl esters of aliphatic amino acids proceeds smoothly in chloroform in the presence of triethylamine. Alkaline hydrolysis of obtained products leads to N-acylated amino acids containing furan heteroring in the acyl radical.

Aminomethyl derivatives of furancarboxylic acids react with 1,4-dicarbonyl compounds under Paal-Knorr reaction conditions to form the pyrrole ring. It is found that α-aminomethyl derivatives of furancarboxylic acids react faster than their β analogs. The carboxy group adjacent to the aminomethyl fragment decelerates the process.

The study was aimed at assessing the efficacy of ozonized normal salines in experimental endophthalmitis. Experiments demonstrated that, as the control group developed grave endophthalmitis and the clinical picture deteriorated by the end of experiment, eventuating in melting of tissues both in the anterior and posterior segments of the eye, in experimental animals, to which ozonized normal saline was administered directly after infection, endophthalmitis either did not develop at all or was less severe. The anterior segment of the eyeball was not involved in the infectious process, and the changes in the vitreous body were not so grave as in the controls, and by the end of experiment the inflammation ceased completely. By the end of the infectious process in the experimental group the majority of tissue structures of the posterior pole of the eyeball, including the retina, were retained. After administration of ozonized normal saline to animals with full-blood endophthalmitis the symptoms of the inflammatory process abated and the disease took a more favorable course than in control. Hence, experiments demonstrated that even a single intravitreal instillation of ozonized solution during an infectious process brings about a high prophylactic and therapeutic effect.