High Anticoagulant Activity Research Articles

Synthesis, Characterization, DFT Calculations and Anticoagulant Activity of Symmetrical and Unsymmetrical N-Aryl Thiourea Derivatives

The present study reports a methodology for the synthesis of symmetrical and unsymmetrical thiourea derivatives 1-9, which have been prepared in good overall yields from condensation reactions between phenylisothiocyanate and different primary amines. The structures of all products were confirmed by the spectroscopic analysis (UV, IR, and NMR). These derivatives were tested for anticoagulant activity using PT and APTT reagents, and those reagents are considered also a controller, the results showed that the theN-aryl thiourea derivatives have very high anticoagulant activity. Theoretical calculations based on DFT/B3LYP method have been performed in order to get insights into the molecular geometry and chemical reactivity of the studied compounds.

Annexin gene family in Spirometra mansoni (Cestoda: Diphyllobothriidae) and its phylogenetic pattern among Platyhelminthes of medical interest.

The plerocercoid larvae of Spirometra mansoni are etiological agents of human and animal sparganosis. Annexins are proteins with important roles in parasites. However, our knowledge of annexins in S. mansoni is still inadequate. In this study, 18 new members of the Annexin (ANX) family were characterized in S. mansoni. The clustering analysis demonstrated that all the SmANXs were divided into two main classes, consistent with the patterns of conserved motif organization. The 18 SmANXs were detected at all developmental stages (plerocercoid, adult, and egg) and displayed ubiquitous but highly variable expression patterns in all tissues/organs studied. The representative member rSmANX18 was successfully cloned and expressed. The protein was immunolocalized in the tegument and parenchyma of the plerocercoid and in the tegument, parenchyma, uterus and egg shell of adult worms. The recombinant protein can bind phospholipids with high affinity in a Ca2+-dependent manner, shows high anticoagulant activity and combines with FITC to recognize apoptotic cells. Annexin gene polymorphism and conservative core motif permutation were found in both cestodes and trematodes. SmANXs also revealed high genetic diversity among Platyhelminthes of medical interest. Our findings lay a foundation for further studies on the biological functions of ANXs in S. mansoni as well as other taxa in which ANXs occur.

Development of plant based bioactive, anticoagulant and antioxidant surface coatings for medical implants

Biomedical implants trigger the activation of thrombo-inflammatory cascades that can impair their performance and potentially cause the serious adverse clinical events including late thrombosis and restenosis. The activation of multifactorial cascades may be inhibited by the active ingredients from natural sources including C. cassia, P. ginseng and O. tenuiflorium . Hence, this study aimed to elucidate and evaluate the potential use of natural drugs to impede the coagulation cascades after biomedical implantation. The natural drugs were incorporated into degradable matrix of poly lactic acid (PLA) with varying concentrations ranging from 1% to 5% and a composite containing all three drugs (1% of each drug). All the compositions were characterized principally by using fourier transform infrared spectroscopy, GC-MS and scanning electron microscopy while the drug release profile of drug was determined by using UV-spectrometry. The DPPH assay, thrombin time and hemolysis tests were performed to determine the antioxidant potential, anticoagulation and hemocompatibility of the novel compositions. The drug-protein interactions were determined through molecular docking. All the films underwent initial burst release depending on their composition which was followed by the sustained release pattern. Additionally, DAPPH and hemolysis assays exhibited good antioxidant and hemocompatibility. Moreover, the films demonstrated high anticoagulation activity by possibly binding with coagulation factors/proteins of extrinsic pathway including factor II, V, VII and X which was observed through docking. The presence of anticoagulation constituents was confirmed through GC-MS. In conclusion, the proposed drug composite expressed the potential of a viable and suitable candidate for biomedical implant coatings. • Natural drugs containing PLA films can be an excellent coating for medical implants • The synergistic effect of multiple natural drugs is better than individual drugs • Increasing drug concentration, subsides rate of drug release and matrix degradation • Composite of drugs is biocompatible, antioxidant, antithrombotic and anticoagulant • Anticoagulation activity of drug composite is due to extrinsic pathway blocking

Synthesis and diverse biological activity profile of triethylammonium isatin-3-hydrazones.

A series of biorelevant triethylammonium isatin hydrazones containing various substituents in the aromatic fragment have been synthesized. Their structure and composition were confirmed by NMR- and IR-spectroscopies, mass-spectrometry and elemental analysis. It was found that some representatives show activity against Staphylococcus aureus and Bacillus cereus higher or at the level of norfloxacin, including methicillin-resistant Staphylococcus aureus strains. The study also showed low hemo- and cytotoxicity (Chang Liver) and high antiaggregatory and anticoagulant activity of these compounds. The high potential of new ammonium isatin-3-acylhydrazones in the search for antimicrobial activity against phytopathogens of bacterial and fungal nature has been shown for the first time.

Design strategy of antidote sequence for bivalent aptamer: Rapid neutralization of high‐anticoagulant thrombin‐binding bivalent DNA aptamer‐linked M08 with HD22

BackgroundBivalent thrombin‐binding aptamers (TBAs) have great potential for the treatment of thrombosis because they exhibit high anticoagulant activity, and their complementary single‐stranded DNA (ssDNA) sequences work as an antidote. However, a design strategy for antidote sequences against bivalent aptamers has not been established. ObjectivesTo develop bivalent TBAs using M08, which exhibits higher anticoagulant activity than the previously reported exosite Ⅰ–binding DNA aptamers, such as HD1, an exosite Ⅱ–binding DNA aptamer (HD22) was linked to M08 with various types of linkers. In addition, short‐length complementary ssDNAs were designed to neutralize the optimized bivalent aptamer effectively and rapidly. ResultsAmong the bivalent aptamers of M08 linked to HD22 with various types of linkers, M08‐T15‐HD22 possessed approximately 5‐fold higher anticoagulant activity than previously reported bivalent aptamers. To neutralize the activity of the 87‐meric M08‐T15‐HD22, complementary ssDNA sequences with different lengths and hybridization segments were designed. The complementary sequence against the M08 moiety played a more important role in neutralizing than that against the HD22 moiety. Hybridization of the T15 linker in the M08‐T15‐HD22 with the A15 sequence in the antidote accelerated neutralization due to toehold‐mediated strand displacement. Interestingly, some shorter‐length antidotes showed higher neutralizing activity than the full complementary 87‐meric antidote, and the shortest, 34‐meric antidote, neutralized most effectively. ConclusionsA pair comprising an 87‐meric bivalent TBA containing M08 and a 34‐meric short‐length antidote with high anticoagulant and rapid neutralizing activities was developed. This design strategy of the DNA sequence can be used for other bivalent DNA aptamers and their antidotes.

Thermally driven formation of polyphenolic carbonized nanogels with high anticoagulant activity from polysaccharides.

We have demonstrated that alginate with negligible anticoagulant activity can be converted into carbonized nanogels with potent anticoagulant activity through a solid-state heating process. The conversion of alginate into graphene-like nanosheet (GNS)-embedded polyphenolic-alginate nanogels (GNS/Alg-NGs) has been carried out through condensation and carbonization processes. The GNS/Alg-NGs exhibit much stronger anticoagulant activity (>520-fold) compared to untreated alginate, mainly because their polyphenolic structures have a high binding affinity [dissociation constant (Kd) = 2.1 × 10-10 M] toward thrombin. In addition, the thrombin clotting time delay caused by the GNS/Alg-NGs is 10-fold longer than that of natural polyphenolic compounds, such as quercetin, catechin, naringenin, caffeic acid, and ferulic acid. The thrombin- or kaolin-activated thromboelastography of whole-blood coagulation reveals that the GNS/Alg-NGs display a much stronger anticoagulant ability than that of untreated alginate and naturally sulfated polysaccharides (fucoidan). The GNS/Alg-NGs exhibit superior biocompatibility and anticoagulant activity, as observed with an in vivo rat model, revealing their potential as a blood thinner for the treatment of thrombotic disorders.

Phytochemicals, Nutritional Value, Antioxidant, and Anticoagulant Activity of Lactuca sativa L. Leaves and Stems

The main ingredient in the daily salad dish is the leaves of Lactuca sativa, while the stems are usually discarded and not eaten. This study was conducted to compare the stems and leaves of two selected L. sativa varieties (L. sativa var. longifolia L. and L. sativa var. capitata L.) related to the preliminary phytochemical investigation, nutrient content, DPPH assay, and in vitro anticoagulant activity by determination of prothrombin time (PT) and activated partial thromboplastin time (aPTT). The findings revealed almost the same phytoconstituents in the leaves and stems of each variety, such as terpenoids, flavonoids, coumarins, and others. Exceptionally, tannins have only been detected in the leaves. Compared to the stems, the leaves of both varieties showed statistically significantly higher levels of raw protein and raw fat. For the DPPH assay, the leaves of both varieties have a statistically significantly higher antioxidant activity than the stems. The leaves and stem extract of the two selected varieties showed a significant prolongation of PT (P <0.05 vs. NS= 12:30 s). On the other hand, the aPTT test showed a significant increase in aPTT (P <0.05 vs. NS = 32:44 s) in the stem extract of both varieties, whereas there was no statistically significant increase in aPTT in the leaves of both varieties. Both parts of each variety have a diversity of phytochemicals and nutrients. The leaves of both varieties have a higher antioxidant activity than the stems. While the stems had higher anticoagulant activity than the leaves.

Antithrombin III-mediated blood coagulation inhibitory activity of chitosan sulfate derivatized with different functional groups

Acylated chitosan sulfate (ChS1), a sulfated polysaccharide with high anticoagulant activity, was chemically synthesized and structurally characterized using FT-IR analysis. The beneficial structural properties and high availability of the sulfate group in ChS1 led to greater anticoagulant activity through both the intrinsic and common pathways with antithrombin III (AT III)-mediated inhibition, particularly involving coagulation factors FXa and FIIa. The analysis of the binding affinities using surface plasma resonance found that the equilibrium dissociation constant (KD) of ChS1 for FXa and FIIa in the presence of AT III was 67.4 nM and 112.6 nM, respectively, indicating the stronger interaction of the AT III/ChS1 complex with the ligands and the inhibition of activated FX and FII. The results of amidolytic assays further demonstrated the stronger inhibition of the proteolytic conversion of factor X by the intrinsic FXase complex and of FII by the prothrombinase complex. Molecular docking analysis further validated the protein-ligand interactions of ChS1 with AT III and their binding affinity.

Anticoagulant activity of fucosylated chondroitin sulfate isolated from Cucumaria syracusana

Fucosylated chondroitin sulfate (FCScs) isolated from sea cucumber Cucumaria syracusana was characterized by Fourier Transform InfraRed spectroscopy (FT-IR), Nuclear Magnetic Resonance (NMR) spectroscopy and high performance size exclusion chromatograph, a multi-angle laser light scattering detector, a viscometer and a differential refractive index (dRI) detector (HPSEC-MALLS-dRI). The anticoagulant activities of FCScs were studied by the classical clotting time assays and the purified systems containing thrombin and antithrombin or heparin cofactor II. The effect on thrombin generation was investigated using calibrated automated thrombography (CAT). The results obtained showed that the FCS with high sulfate content 31 % and relatively low average molecular weight of 36.3 kDa was isolated from C. syracusana in amount of ∼ 35.6 mg/g dry body wall. Structural analysis of this polysaccharide revealed the presence backbone structure of chondroitin sulfate chain branched by two types of fucose 2,4-O-di and 3,4-O-disulfated residues in respective ratios of 57.5 and 42.5 %. The FCScs exhibited a high anticoagulant activity mediated essentially by heparin cofactor II (HCII) and to lesser extent by antithrombin (AT) with IC50 values of 0.05 μg/mL and 0.09 μg/mL, respectively. Furthermore, the results of CAT assay showed that the velocity index decreases 3-times at 50 μg/mL in comparison with normal plasma. The overall results showed high anticoagulant activity attributed to the high sulfate content and abundance of disulfated fucose branches of FCScs which made it a promising candidate of anticoagulation drug.

Anticoagulant Decapeptide Interacts with Thrombin at the Active Site and Exosite-I.

Thrombin can be used as a target for its inhibitors to prevent blood coagulation. A novel peptide (TKLTEEEKNR, PfCN) identified from αS2-casein (fragments 211-220) with high anticoagulant activity was screened and prepared. The activated partial thromboplastin time, prothrombin time, and thrombin time, at the concentration of 4 mM, prolonged about 19, 2.5 and 5.5 s, respectively. At the same concentration, the fibrinogen clotting time prolonged from 25.5 ± 0.7 to 38.3 ± 1.3 s. The thrombin inhibitory efficiency in vitro (IC50 value of 29.27 mM) and antithrombosis effect in vivo were determined. The secondary structure of thrombin, which was influenced by PfCN, indicates that PfCN can bind to thrombin. Isothermal titration calorimetry and the chromogenic substrate test showed that PfCN belongs to the bivalent thrombin inhibitor like bivalirudin. Although the effect was not as good as bivalirudin, in the animal experiment, bleeding occurred in the bivalirudin group but not in the PfCN group. Moreover, molecular docking illustrates the mechanism for the antithrombin activity of PfCN. These results indicated that PfCN could be used as an effective thrombin inhibitor with broad potential for the prevention of thrombotic acute pulmonary embolism and other thrombotic events.

Anticoagulant Activity of Sulfated Ulvan Isolated from the Green Macroalga Ulva rigida.

(1) Background: Brown and red algal sulfated polysaccharides have been widely described as anticoagulant agents. However, data on green algae, especially on the Ulva genus, are limited. This study aimed at isolating ulvan from the green macroalga Ulva rigida using an acid- and solvent-free procedure, and investigating the effect of sulfate content on the anticoagulant activity of this polysaccharide. (2) Methods: The obtained ulvan fraction was chemically sulfated, leading to a doubling of the polysaccharide sulfate content in a second ulvan fraction. The potential anticoagulant activity of both ulvan fractions was then assessed using different assays, targeting the intrinsic and/or common (activated partial thromboplastin time), extrinsic (prothrombin time), and common (thrombin time) pathways, and the specific antithrombin-dependent pathway (anti-Xa and anti-IIa), of the coagulation cascade. Furthermore, their anticoagulant properties were compared to those of commercial anticoagulants: heparin and Lovenox®. (3) Results: The anticoagulant activity of the chemically-sulfated ulvan fraction was stronger than that of Lovenox® against both the intrinsic and extrinsic coagulation pathways. (4) Conclusion: The chemically-sulfated ulvan fraction could be a very interesting alternative to heparins, with different targets and a high anticoagulant activity.

Recombinant dermatan sulfate is a potent activator of heparin cofactor II-dependent inhibition of thrombin.

The glycosaminoglycan dermatan sulfate (DS) is a well-known activator of heparin cofactor II-dependent inactivation of thrombin. In contrast to heparin, dermatan sulfate has never been prepared recombinantly from material of non-animal origin. Here we report on the enzymatic synthesis of structurally well-defined DS with high anticoagulant activity. Using a microbial K4 polysaccharide and the recombinant enzymes DS-epimerase 1, dermatan 4-O-sulfotransferase 1, uronyl 2-O-sulfotransferase and N-acetylgalactosamine 4-sulfate 6-O-sulfotransferase, several new glycostructures have been prepared, such as a homogenously sulfated IdoA-GalNAc-4S polymer and its 2-O-, 6-O- and 2,6-O-sulfated derivatives. Importantly, the recombinant highly 2,4-O-sulfated DS inhibits thrombin via heparin cofactor II, approximately 20 times better than heparin, enabling manipulation of vascular and extravascular coagulation. The potential of this method can be extended to preparation of specific structures that are of importance for binding and activation of cytokines, and control of inflammation and metastasis, involving extravasation and migration.

Effect of various extraction methods on the structure of polyphenolic-polysaccharide conjugates from Fragaria vesca L. leaf.

The purpose of this study was to compare the application of several extraction methods, including cold extraction (CAE), hot extraction (HAE), ultrasonic-assisted extraction (UAE), and microwave-assisted extraction (MAE), all carried out in 0.1 M NaOH, under their respective best parameters, for obtaining products from leaf of Fragaria vesca L. The extracts with the highest anticoagulant activity were purified by multi-step extraction procedure and separated by gel permeation chromatography, giving rise to the macromolecular complexes. They were subsequently structurally characterized using colorimetric methods, FT-IR, GC-MS, and NMR (1H and 1H/13C HSQC), as polyphenolic-polysaccharide conjugates with the anticoagulant activity. The polysaccharide parts of the conjugates obtained by different extraction procedures were found to vary significantly. The most selective in their activity were the glycoconjugates extracted in UAE and MAE processes, i.e. arabinogalactan and pectin-like conjugates, respectively. In terms of their anticoagulant activity all of them were non-direct factor Xa inhibitors mediated by antithrombin.

Anticoagulant Activity of Some Ficus carica Varieties Extracts Grown in Algeria

Abstract The hemostatic system is a complex balanced system that triggers clot formation to prevent blood loss after trauma. To block abnormal bleeding and maintain intravascular blood in a liquid state, in this study we investigated the possible anticoagulant effect of leaves and fruits extracts from some fig varieties grown in Algeria by determining the quick time (QT). The blood samples of the healthy individuals were used. For in vitro coagulation assays, the clotting times obtained in the presence of polyphenols in different extracts of F.carica samples indicate that they exert a high anticoagulant activity on the exogenous pathway of coagulation. Moreover, the polyphenolic extract of ‘Roudane’ variety presented a substantial increase in coagulation. Based on these preliminary results, it can be suggested that the fig polyphenolic extracts (FPE) of this varieties have anticoagulant activity that could be useful in preventing blood clots.

The effect of heparin hydrogel embedding on glutaraldehyde fixed bovine pericardial tissues: Mechanical behavior and anticalcification potential.

Heart valve diseases remain common in industrialized countries. Bioprosthetic heart valves, introduced as free of anticoagulation therapy alternatives to mechanical substitutes. Still they suffer from long term failure due to calcification. Different treatment methods introduced to inhibit calcification, have so far been limited in success. Glycosaminoglycans (GAGs) possess properties including high negative charge, anticoagulation and anti-inflammatory activity that make them a potential solution for calcification problem. In this study, heparin hydrogel was prepared and characterized both chemically and mechanically. After that, heparin hydrogel embedded bovine pericardial tissues, fixed with glutaraldehyde, were produced and tested for their mechanical behavior and anticalcifcation potential in vitro using the constant composition model. In the calcification experiments, tissues were divided into three groups: a) Controls without treatment, b) Hydrogel treated tissues and c) Tissues with raw heparin dissolved in the calcification solution. The results showed that embedding of tissue with hydrogel had no stiffening effect on its mechanical behavior. Calcification assessment showed a significant efficacy on inhibition of calcium phosphate deposition of hydrogel treated (second group) in comparison to untreated tissues (control, first group). Calcification inhibition potential was very similar in both the second and raw heparin (third group). Histological data confirmed the obtained results, suggesting that heparin treatment is a promising anticalcification agent.

Primary structure and anticoagulant activity of fucoidan from the sea cucumber Holothuria polii

Sea cucumber fucoidan is recently endowed with a variety of biological activities. In the present study, we studied the structure and anticoagulant effect of fucoidan from the sea cucumber Holothuria polii (Fuc-Hp). The Fuc-Hp was purified by anion exchange chromatography and its structure was characterized by FT-IR and NMR spectroscopy. Molecular weight measurements were performed by HPSEC-MALLS-dRI. Fuc-Hp anticoagulant activity was measured by activated partial thromboplastin and thrombin times, and by in vitro thrombin inhibition in the presence of antithrombin and heparin cofactor II. The assessment of thrombin generation was investigated using calibrated automated thrombography. Fuc-Hp with a high sulfate content (34.6%) and an average molecular mass of 1376.3 kDa was isolated from H. polii in amount of ~2.7 mg/g dry body wall. Primary structural analysis indicated that Fuc-Hp was mainly composed of a tetrafucose repeating unit branched by glucuronic acid. Fuc-Hp exhibited a high anticoagulant effect mediated essentially by heparin cofactor II and to lesser extent by antithrombin with IC50 values of 0.16 μg/mL and 0.5 μg/mL, respectively. Overall results showed a high anticoagulant activity of Fuc-Hp, which was attributed to the high sulfate content and abundance of disulfated fucose residues of H. polii fucoidan.

Can we reliably predict the level of anticoagulation after enoxaparin injection in elderly patients with renal failure?

The aim of this study was to evaluate the activity of anti-activated factor X (anti-Xa) in patients with different degrees of chronic renal failure (CRF), treated with therapeutic doses of low molecular weight heparin. This prospective study evaluated the effect of age, renal function, BMI, gender, in determining the efficacy and safety of treatment with enoxaparin, evaluated by assessing the anti-Xa. The therapeutic anticoagulant range was set between 0.20 and 0.70U/mL. Two hospital geriatric units. 98 patients (64 men, 34 women, mean age 82years) with CRF, treated with enoxaparin at therapeutic dosage, for deep vein thrombosis or acute coronary syndrome. Anti-Xa was assessed 4h after the third administration of LMWH using Chromogenix test. Renal function was assessed by calculating creatinine clearance according to Cockcroft formula. The dose of enoxaparin ranged between 53 and 200U/kg; total 4000-16000U/day. The mean anti-Xa was 0.41U/mL (95% CI 0.36-0.45). Multiple regression analysis selected only the dose of enoxaparin, but not age, creatinine clearance, BMI, gender, as a predictor of anti-Xa serum levels. In seven patients anti-Xa was above the range but none of them received more than 150U/Kg enoxaparin (100U/kg if creatinine clearance <30mL/min). Ten patients (eight men, two women) showed suboptimal levels of anti-Xa, regardless enoxaparin dose or creatinine clearance. Enoxaparin dose reduction according to renal function decreases the risk of overdosing and potentially the risk of bleeding. The risk of under dosing seems less predictable; therefore, anti-Xa assay may be useful in severe clinical situations that require higher anticoagulant activity.

Quality Assessment of Panax notoginseng from Different Regions through the Analysis of Marker Chemicals, Biological Potency and Ecological Factors.

Panax notoginseng (Burk.) F.H. Chen, called Sanqi in China, is a perennial herb that has been used as a medicinal herb in traditional Chinese medicine for more than 400 years. Because notoginseng is included in many proprietary Chinese medicines, the quality of notoginseng directly affects its efficacy and safety. However, considering the complex and special growth environment requirements of notoginseng, it is insufficient to evaluate its quality based solely on the analysis of marker chemicals. Thus, in this study, we tried to evaluate the quality of notoginseng with integrated indicators: (1) the concentration of five marker chemicals, notoginsenoside R1, ginsenoside Rg1, ginsenoside Re, ginsenoside Rb1 and ginsenoside Rd; (2) the anticoagulant activity (ACA); and (3) twenty-one ecological factors (e.g., longitude, latitude, elevation and soil data). Using these 27 parameters, notoginseng from different regions could be distinguished effectively, indicating a remarkable divergence of quality. A correlation analysis showed that variations of the ecological factors were closely associated with the saponins content and biopotency. For instance, the total nitrogen (TN), alkali hydrolysis nitrogen (AHN) and rapidly available potassium (RAPT) were significantly correlated with ACA, and RAPT was significantly correlated with the content of ginsenoside Rd and notoginsenoside R1. The results demonstrated that the high-quality notoginseng was produced from the emerging regions such as Kunming, Qujing and Honghe, which had higher ACA and saponin content than the notoginseng produced in traditional regions such as Wenshan and Baise.

Identification and characterization of novel anticoagulant peptide with thrombolytic effect and nutrient oligopeptides with high branched chain amino acid from Whitmania pigra protein.

Natural and nutrient substances for cardiovascular disease are promising and capture researchers' minds. Two kinds of novel bioactive peptides (high Fischer's ratio oligopeptides and anticoagulant peptides) were obtained from Whitmania pigra protein via enzymatic hydrolysis. An oligopeptide (MW<874.0Da) named as HF2 was obtained via chromatography purification procedures with a high Fischer's ratio of 31.92±1.36 and low phenylalanine+tyrosine content of 0.98±0.04%. Another peptide (WA3-1), prepared by alcalase AF 2.4L-catalyzed hydrolysis and then purified by DEAE Sepharose FF, gel Sephadex G-15 chromatography, exhibited high anticoagulant activity with prolonging significantly plasma clotting time on activated partial thromboplastin time, prothrombin time, thrombin time (p<0.01) and powerful thrombolytic activity. Amino acid composition and MALDI-TOF/TOF MS analysis showed that WA3-1 contained 11 amino acids (MW: 1422.0Da) with the sequence as NH2-His-Asp-Phe-Leu-Asn-Asn-Lys-Leu-Glu-Tyr-Glu-COOH. Abundant negatively charged amino acids in C-terminal, as well as the special residue Lys contribute to its anticoagulant capacity. This research provided a novel natural candidate for the manufacture of nutrient oligopeptides with high branched chain amino acid, and anticoagulant thrombolytic agent in pharmaceutical industry with helping prevent from thrombosis and related cardiovascular diseases.

Chemically sulfated natural galactomannans with specific antiviral and anticoagulant activities

Naturally occurring galactomannans were sulfated to give sulfated galactomannans with degrees of substitution of 0.7–1.4 per sugar unit and molecular weights of M¯n=0.6×104–2.4×104. Sulfated galactomannans were found to have specific biological activities in vitro such as anticoagulant, anti-HIV and anti-Dengue virus activities. The biological activities were compared with those of standard dextran and curdlan sulfates, which are polysaccharides with potent antiviral activity and low cytotoxicity. It was found that sulfated galactomannans had moderate to high anticoagulant activity, 13.4–36.6unit/mg, compared to that of dextran and curdlan sulfates, 22.7 and 10.0unit/mg, and high anti-HIV and anti-Dengue virus activities, 0.04–0.8μg/mL and 0.2–1.1μg/mL, compared to those curdlan sulfates, 0.1μg/mL, respectively. The cytotoxicity on MT-4 and LCC-MK2 cells was low. Surface plasmon resonance (SPR) of sulfated galactomannans revealed strong interaction with poly-l-lysine as a model compound of virus proteins, and suggested that the specific biological activities might originate in the electrostatic interaction of negatively charged sulfate groups of sulfated galactomannans and positively charged amino groups of surface proteins of viruses. These results suggest that sulfated galactomannans effectively prevented the infection of cells by viruses and the degree of substitution and molecular weights played important roles in the biological activities.