Pharmacological Activities of Sulfated Fucose-Rich Polysaccharides after Oral Administration: Perspectives for the Development of New Carbohydrate-Based Drugs.

Marine organisms are a source of active biomolecules with immense therapeutic and nutraceutical potential. Sulfated fucose-rich polysaccharides are present in large quantities in these organisms with important pharmacological effects in several biological systems. These polysaccharides include sulfated fucan (as fucoidan) and fucosylated chondroitin sulfate. The development of these polysaccharides as new drugs involves several important steps, among them, demonstration of the effectiveness of these compounds after oral administration. The oral route is the more practical, comfortable and preferred by patients for long-term treatments. In the past 20 years, reports of various pharmacological effects of these polysaccharides orally administered in several animal experimental models and some trials in humans have sparked the possibility for the development of drugs based on sulfated polysaccharides and/or the use of these marine organisms as functional food. This review focuses on the main pharmacological effects of sulfated fucose-rich polysaccharides, with an emphasis on the antidislipidemic, immunomodulatory, antitumor, hypoglycemic and hemostatic effects.

Fucosylated Chondroitin Sulfates from the Sea Cucumbers Paracaudina chilensis and Holothuria hilla: Structures and Anticoagulant Activity.

Fucosylated chondroitin sulfates (FCSs) PC and HH were isolated from the sea cucumbers Paracaudina chilensis and Holothuria hilla, respectively. The purification of the polysaccharides was carried out by anion-exchange chromatography on a DEAE-Sephacel column. The structural characterization of the polysaccharides was performed in terms of monosaccharide and sulfate content, as well as using a series of nondestructive NMR spectroscopic methods. Both polysaccharides were shown to contain a chondroitin core [→3)-ß-d-GalNAc (N-acethyl galactosamine)-(1→4)-ß-d-GlcA (glucuronic acid)-(1→]n, bearing sulfated fucosyl branches at O-3 of every GlcA residue in the chain. These fucosyl residues were different in their pattern of sulfation: PC contained Fuc2S4S and Fuc4S in a ratio of 2:1, whereas HH included Fuc2S4S, Fuc3S4S, and Fuc4S in a ratio of 1.5:1:1. Moreover, some GalNAc residues in HH were found to contain an unusual disaccharide branch Fuc4S-(1→2)-Fuc3S4S-(1→ at O-6. Sulfated GalNAc4S6S and GalNAc4S units were found in a ratio of 3:2 in PC and 2:1 in HH. Both polysaccharides demonstrated significant anticoagulant activity in a clotting time assay, which is connected with the ability of these FCSs to potentiate the inhibition of thrombin and factor Xa in the presence of anti-thrombin III (ATIII) and with the direct inhibition of thrombin in the absence of any cofactors.

A novel structural fucosylated chondroitin sulfate from Holothuria Mexicana and its effects on growth factors binding and anticoagulation.

Fucosylated chondroitin sulfate (FCS), a structurally distinct glycosaminoglycan from the body wall of sea cucumber, possesses many biological properties and pharmacology functions. The refined structure of FCS isolated from sea cucumber Holothuria Mexicana (FCShm) was characterized by NMR spectra and HILIC-FTMS, which demonstrated four types of branches in FCShm. Among these, two branches were α-L-Fuc-2S4S (where Fuc is fucose and S is sulfo) and α-L-Fuc-4S linked to O-3 of glucuronic acid residues, while others were identified as α-L-Fuc-4S and α-L-Fuc-3S4S attached to O-6 of N-acetylgalactosamine residue. Furthermore, the fucosyl branches were α-1,3-linked with different degree of polymerization from 1 to 5. FCShm exhibited high affinity to fibroblast growth factor 1 and 2, growth factors involved in neovascularization. Moreover, FCShm displayed intrinsic anticoagulant activity and inhibited thrombin and factor Xa activation by antithrombin III. Our results proposed a novel structural FCS and demonstrated its favorable application prospects in anti-angiogenesis and anticoagulation.

Purification, structural characterization and anticoagulant properties of fucosylated chondroitin sulfate isolated from Holothuria mexicana.

A novel fucosylated chondroitin sulfate (HmG) was isolated from sea cucumber Holothuria mexicana, the structure of which was characterized by monosaccharide composition, disaccharide composition, IR, 1H and 13C NMR spectrum, additionally with two dimensional NMR spectrum of degraded HmG (DHmG). The backbone of HmG was identified as chondroitin 6-O sulfate, while the major O-4 sulfated fucose branches linked to O-3 position of glucuronic acid in almost every disaccharide unit. The anticoagulant activities of HmG and DHmG were assessed and compared with heparin and low molecular weight heparin. The results indicated that HmG and DHmG both could significantly prolong the activated partial thrombo-plastin time, and the properties were well related to its molecular weight. DHmG showed similar anticoagulant properties to low molecular weight heparin with less bleeding risks, making it a safer anticoagulant drug.

Occurrence of sulfated fucose branches in fucosylated chondroitin sulfate are essential for the polysaccharide effect preventing muscle damage induced by toxins and crude venom from Bothrops jararacussu snake.

Snake envenoming is an important public health problem around the world, particularly in tropics. Beyond deaths, morbidity induced by snake venoms, such as myotoxicity, is of pivotal consequence to population. Bothrops jararacussu is the main venomous snake in southeast region of Brazil, and particularly presents strong myotoxic effect. The only available therapy, antibothropic antivenom, poorly affects venom-induced myotoxicity. The aim of this study is to assess the ability of fucosylated chondroitin sulfate (fucCS), a glycosaminoglycan with anticoagulant and antithrombotic properties, and its derivatives to inhibit toxic activities of B. jararacussu crude venom and its isolated toxins, named bothropstoxins (BthTX-I and BthTX-II). The in vitro myotoxic activities induced by crude venom, by BthTX-I alone and by toxins together were abolished by fucCS. Carboxyl reduction (fucCS-CR) kept this ability whereas defucosilation (defucCS) abrogates myoprotection. We observed the same pattern in the response of these polysaccharides in antagonizing the increase in plasma creatine kinase (CK) levels, the reduction of skeletal muscle CK content and the rise of myeloperoxidase (MPO) activity induced by crude venom and isolated toxins. FucCS inhibited edematogenic activity and partially prevented the reduction of total leukocytes in blood when pre-incubated with crude venom. Furthermore, the venom procoagulant effect was completely antagonized by increasing concentrations of fucCS, although this polyanion could stop neither the tail bleeding nor the skin hemorrhage induced by Bothrops jararaca venom. The B. jararacussu phospholipase, hyaluronidase, proteolytic and collagenase activities were inhibited in vitro. The results suggest that fucCS could be able to interact with both toxins, and it is able to inhibit BthTX-II phospholipase activity. Light microscopy of extensor digitorum longus muscle (EDL) muscle showed myoprotection by fucCS, once necrotic areas, edema and inflammatory cells were all decreased as compared to venom injection alone. Altogether, data show that fucCS was able to inhibit myotoxicity and inflammation induced by B. jararacussu venom and its phospholipase toxins, BthTX-I and BthTX-II. Thus, fucosylated chondroitin sulfate is a new polyanion with potential to be used as an adjuvant in the treatment of snakebites in the future.

Specific sulfation and glycosylation-a structural combination for the anticoagulation of marine carbohydrates.

Based on considered achievements of the last 25 years, specific combinations of sulfation patterns and glycosylation types have been proved to be key structural players for the anticoagulant activity of certain marine glycans. These conclusions were obtained from comparative and systematic analyses on the structure-anticoagulation relationships of chemically well-defined sulfated polysaccharides of marine invertebrates and red algae. These sulfated polysaccharides are known as sulfated fucans (SFs), sulfated galactans (SGs) and glycosaminoglycans (GAGs). The structural combinations necessary for the anticoagulant activities are the 2-sulfation in α-L-SGs, the 2,4-di-sulfation in α-L-fucopyranosyl units found as composing units of certain sea-urchin and sea-cucumber linear SFs, or as branching units of the fucosylated chondroitin sulfate, a unique GAG from sea-cucumbers. Another unique GAG type from marine organisms is the dermatan sulfate isolated from ascidians. The high levels of 4-sulfation at the galactosamine units combined with certain levels of 2-sulfation at the iduronic acid units is the anticoagulant structural requirements of these GAGs. When the backbones of red algal SGs are homogeneous, the anticoagulation is proportionally dependent of their sulfation content. Finally, 4-sulfation was observed to be the structural motif required to enhance the inhibition of thrombin via heparin cofactor-II by invertebrate SFs.