Structural peculiarities of polysaccharide from sterile form of Far Eastern red alga Ahnfeltiopsis flabelliformis

Carrageenans and Their Oligosaccharides from Red Seaweeds Ahnfeltiopsis flabelliformis and Mastocarpus pacificus (Phyllophoraceae) and Their Antiproliferative Activity

Comparative structural analysis of gelling polysaccharides from A. flabelliformis and M. pacificus belonging to Phyllophoraceae and the effect of their structural features and molecular weight on human colon cancer cell lines (HT-29, DLD-1, HCT-116) was carried out. According to chemical analysis, IR and NMR spectroscopies, M. pacificus produces kappa/iota-carrageenan with a predominance of kappa units and minor amounts of mu and/or nu units, while the polysaccharide from A. flabelliformis is iota/kappa-carrageenan (predominance of iota units) and contains negligible amounts of beta- and nu-carrageenans. Iota/kappa- (Afg-OS) and kappa/iota-oligosaccharides (Mp-OS) were obtained from the original polysaccharides through mild acid hydrolysis. The content of more sulfated iota units in Afg-OS (iota/kappa 7:1) was higher than in Mp-OS (1.0:1.8). The poly- and oligosaccharides up to 1 mg/mL did not show a cytotoxic effect on all tested cell lines. Polysaccharides showed an antiproliferative effect only at 1 mg/mL. Oligosaccharides had a more pronounced effect on HT-29 and HCT-116 cells than the original polymers, while HCT-116 cells were slightly more sensitive to their action. Kappa/iota-oligosaccharides exhibit a greater antiproliferative effect and more strongly decrease the number of colonies forming in HCT-116 cells. At the same time, iota/kappa-oligosaccharides inhibit cell migration more strongly. Kappa/iota-oligosaccharides induce apoptosis in the SubG0 and G2/M phases, while iota/kappa-oligosaccharides in the SubG0 phase.

Structural peculiarities of carrageenans from Far Eastern red seaweed Mazzaella parksii (Gigartinaceae)

The sulfated polysaccharides from cystocarpic plants of Mazzaella parksii were studied. Fractionation at a given KCl concentration allowed us to assume, and stepwise fractionation to prove, that these polysaccharides consisted of several carrageenans that differed in structure and molecular weight. As a result of stepwise fractionation with KCl, nine gelling (1-9) and one non-gelling (10) fractions were obtained. Using IR spectroscopy, it was shown that fractions 3, 4 and 5 were kappa/iota-, kappa- and kappa/beta-carrageenans, respectively. The structures of the main fractions 1, 2, 9 and 10 were investigated in more detail by methylation, NMR spectroscopy and mass spectrometry. Fractions 1 and 2 were hybrid kappa/iota-carrageenans with kappa:iota ratio 79:21 and 63:37, respectively. At the same time, fraction 9 contained kappa-, iota- and small amounts of nu-carrageenans. The fraction 10 had complex structure and was built from kappa-, iota-, beta-, mu- and nu-carrageenans and included agar-like structure, which explained the inability of this fraction to gel at 15 % KCl. It was shown that isolated polysaccharides activated the classical pathway of complement system, increasing the concentration of C1 inhibitor of serine protease by 50 % compared with the negative control.

Mucoadhesive Marine Polysaccharides

Mucoadhesive polymers are of growing interest in the field of drug delivery due to their ability to interact with the body’s mucosa and increase the effectiveness of the drug. Excellent mucoadhesive performance is typically observed for polymers possessing charged groups or non-ionic functional groups capable of forming hydrogen bonds and electrostatic interactions with mucosal surfaces. Among mucoadhesive polymers, marine carbohydrate biopolymers have been attracting attention due to their biocompatibility and biodegradability, sample functional groups, strong water absorption and favorable physiochemical properties. Despite the large number of works devoted to mucoadhesive polymers, there are very few systematic studies on the influence of structural features of marine polysaccharides on mucoadhesive interactions. The purpose of this review is to characterize the mucoadhesive properties of marine carbohydrates with a focus on chitosan, carrageenan, alginate and their use in designing drug delivery systems. A wide variety of methods which have been used to characterize mucoadhesive properties of marine polysaccharides are presented in this review. Mucoadhesive drug delivery systems based on such polysaccharides are characterized by simplicity and ease of use in the form of tablets, gels and films through oral, buccal, transbuccal and local routes of administration.

Intermolecular Interactions in the Formation of Polysaccharide-Gelatin Complexes: A Spectroscopic Study

Gelatin, due to its gelling and stabilizing properties, is one of the widely used biopolymers in biotechnology, medicine, pharmaceuticals, and the food industry. One way to modify the characteristics of gelatin is molecular modification by forming non-covalent polyelectrolyte complexes with polysaccharides based on the self-organization of supramolecular structures. This review summarizes recent advances in the study of various types and the role of intermolecular interactions in the formation of polysaccharide-gelatin complexes, and conformational changes in gelatin, with the main focus on data obtained by spectroscopic methods: UV, FT-IR, and 1H NMR spectroscopy. In the discussion, the main focus is on the complexing polysaccharides of marine origin-sodium alginate, κ-carrageenan, and chitosan. The prospects for creating polysaccharide-gelatin complexes with desired physicochemical properties are outlined.

Influence of the Structural Features of Carrageenans from Red Algae of the Far Eastern Seas on Their Antiviral Properties

The structural diversity and unique physicochemical properties of sulphated polysaccharides of red algae carrageenans (CRGs), to a great extent, determine the wide range of their antiviral properties. This work aimed to compare the antiviral activities of different structural types of CRGs: against herpes simplex virus type 1 (HSV-1) and enterovirus (ECHO-1). We found that CRGs significantly increased the resistance of Vero cells to virus infection (preventive effect), directly affected virus particles (virucidal effect), inhibited the attachment and penetration of virus to cells, and were more effective against HSV-1. CRG1 showed the highest virucidal effect on HSV-1 particles with a selective index (SI) of 100. CRG2 exhibited the highest antiviral activity by inhibiting HSV-1 and ECHO-1 plaque formation, with a SI of 110 and 59, respectively, when it was added before virus infection. CRG2 also significantly reduced the attachment of HSV-1 and ECHO-1 to cells compared to other CRGs. It was shown by molecular docking that tetrasaccharides—CRGs are able to bind with the HSV-1 surface glycoprotein, gD, to prevent virus–cell interactions. The revealed differences in the effect of CRGs on different stages of the lifecycle of the viruses are apparently related to the structural features of the investigated compounds.

Physicochemical characterization and antioxidant activity of sulphated polysaccharides derived from Porphyra haitanensis

This study was designed to fully characterize Porphyra haitanensis polysaccharides, and to evaluate their antioxidant activity. The polysaccharides primarily contained galactose and 3,6-anhydrogalactose in a molar ratio of 1.2:1.0, respectively and sulfate content about 3.8%. The molecular weight of polysaccharides is 2.5 × 10⁵ Da. Scanning electron microscopy and atomic force microscopy of the polysaccharides pointed towards an irregular network with more or less hexagonal and a few rectangular pores. The chemical structure was confirmed through Fourier transform infrared spectroscopy, and 1D and 2D nuclear magnetic resonance structural characterization wherein → 4-3,6-anhydro-α-L-galactopyranose-(1 → 3)-β-D-galactopyranose segments. The extracted polysaccharides revealed relatively high 2, 2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid radical scavenging activity (53.16% at 2 mg/mL), moderate 2,2-diphenyl-1-picrylhydrazyl radical scavenging efficacy (34.63% at 2 mg/mL), and low hydroxyl radical scavenging potential (23.80% at 2 mg/mL). Further purification of these polysaccharides, hence, is advised for their potential role as antioxidants in the food, pharmaceutical and cosmeceutical industry.

Structural characteristics of carrageenans of red alga Mastocarpus pacificus from sea of Japan

The sulfated polysaccharide from sterile alga Mastocarpus pacificus was investigated. Partial reductive hydrolysis and NMR spectroscopy showed that the extracted polysaccharides were only carrageenans. According to FT-IR- and NMR spectroscopy this polysaccharide was a hybrid kappa/iota-carrageenan with a predominance of kappa-type units. According to MALDI-TOFMS, oligosaccharide fragments obtained by mild acid hydrolysis had a polymerization degree of 1-9, while chains built up of galactose residues were up to 3. Tandem ESI mass spectrometry together with innovative ¹⁸O-labelling method showed that the polymer chain of the carrageenan included kappa-carrabiose, kappa-carratetraose, iota-carrabiose, hybrid kappa/iota oligosaccharide units and contained minor insertions of mu-carrageenan (the precursor of kappa-carrageenan). Parallel artificial membrane permeability assay shown that the studied carrageenan inhibited bile salts permeation through an artificial membrane imitating the gastrointestinal barrier by 50 % on average compared to negative control independent of incubation time. However, its action was less pronounced than the hindering ability of cholestyramine.

Mucoadhesive properties of sulphated polysaccharides carrageenans from red seaweed families Gigartinaceae and Tichocarpaceae

The mucoadhesive properties of different types of carrageenan (kappa-, kappa/beta-, iota/kappa- and lambda-CRGs) isolated from red seaweed families Gigartinaceae and Tichocarpaceae collected on the Pacific coast were studied. We examined the interaction between CRGs and pig stomach mucin in dilute aqueous solutions using a set of methods. Measurements of the dynamic light scattering of mucin in the presence of CRG showed that the polysaccharides cause aggregation of mucin particles, as confirmed by microscopy data. The addition of CRGs to solutions of mucin resulted in the formation of a mixture that changed the charge of mucin, especially in the case of kappa- and kappa/beta-CRGs. The interaction between CRG and porcine gastric mucin in the presence of various additives confirmed that hydrogen bonds and electrostatic interactions are complemented when CRG and mucin are mixed in an aqueous medium, which is also confirmed by in vitro methods based on measurements of work of adhesion and shear stress. Kappa- and kappa/beta-CRGs that contain 3,6-anhydro-α-d-galactopyranose chains (DA) have high molecular weight and exhibit a high density of available hydrogen bonding groups able to interact more strongly with mucin glycoproteins.

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.

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update for 2013-2014

This review is the eighth update of the original article published in 1999 on the application of Matrix-assisted laser desorption/ionization mass spectrometry (MALDI) mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2014. Topics covered in the first part of the review include general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation, and arrays. The second part of the review is devoted to applications to various structural types such as oligo- and poly- saccharides, glycoproteins, glycolipids, glycosides, and biopharmaceuticals. Much of this material is presented in tabular form. The third part of the review covers medical and industrial applications of the technique, studies of enzyme reactions, and applications to chemical synthesis. © 2018 Wiley Periodicals, Inc. Mass Spec Rev 37:353-491, 2018.

Recent Advances in Marine Algae Polysaccharides: Isolation, Structure, and Activities

Marine algae have attracted a great deal of interest as excellent sources of nutrients. Polysaccharides are the main components in marine algae, hence a great deal of attention has been directed at isolation and characterization of marine algae polysaccharides because of their numerous health benefits. In this review, extraction and purification approaches and chemico-physical properties of marine algae polysaccharides (MAPs) are summarized. The biological activities, which include immunomodulatory, antitumor, antiviral, antioxidant, and hypolipidemic, are also discussed. Additionally, structure-function relationships are analyzed and summarized. MAPs' biological activities are closely correlated with their monosaccharide composition, molecular weights, linkage types, and chain conformation. In order to promote further exploitation and utilization of polysaccharides from marine algae for functional food and pharmaceutical areas, high efficiency, and low-cost polysaccharide extraction and purification methods, quality control, structure-function activity relationships, and specific mechanisms of MAPs activation need to be extensively investigated.

Further studies on structure of fucoidan from brown alga Saccharina gurjanovae

A sulfated galactofucan SgF (MW 123kDa) was purified from the brown alga Saccharina gurjanovae. Polysaccharide was depolymerized by autohydrolysis at 25 and 60°C, and products were studied by mass spectrometry and (13)C NMR spectroscopy. According to results of investigation, the main chain of this polysaccharide is built of a repeating units →3)-α-L-Fucp-(2,4-OSO3(-))-(1→. Fucose chains could be sometimes terminated by (1→3)-linked galactose residues. Shorter (1→4)- and/or (1→6)-linked sulfated galactose chains are attached at positions C-2, C-3 of fucose residues. Sulfate groups can occupy positions C-2 and/or sometimes C-3 of Gal residues, but a sulfation at C-4 of the galactofucan could not be excluded. The SgF-AH25-H preparation (71kDa) was obtained by autohydrolysis of SgF at 25°C, which leaded to a selective desulfation at C-2 and, probably, to a cleavage of galactose chains, since structure of SgF-AH25-H represented a repeating unit →3)-α-l-Fucp-(4-OSO3(-))-(1→, which was definitely established by (13)C NMR spectroscopy. Galactofucan SgF and its derivative SgF-AH25-H exhibited no cytotoxic activity and leaded to about the same colony formation inhibition in colon cancer DLD-1 cells. Hence, structural simplification of SgF by lowering its molecular weight, desulfation at C-2 and removing of galactose residues by autohydrolysis at 25°C did not decrease its anticancer activity. This procedure allows obtaining standardized products which can be used as medical.