昆布多糖硫酸酯化修饰及抗肿瘤活性的研究

对昆布多糖进行硫酸酯化修饰,考察修饰前后多糖结构及抗肿瘤活性的变化。采用氯磺酸-吡啶法进行多糖硫酸酯化修饰,考察了昆布多糖及其硫酸酯的红外光谱、核磁光谱特征,扫描电镜观察了表面形态,采用MTT比色法进行抗肿瘤活性评价。结果表明,昆布多糖及其硫酸酯都具有典型的多糖红外吸收,昆布多糖硫酸酯具有硫酸基的特征吸收峰;昆布多糖及其硫酸酯均是以β-(1→3)糖苷键为主链的多糖,昆布多糖硫酸酯的硫酸基取代位置在C2-OH与C6-OH。昆布多糖及其硫酸酯表面立体形态差异显著,昆布多糖表面呈云雾状或海绵状,昆布多糖硫酸酯表面呈片状或块状。昆布多糖及其硫酸酯对人肠癌细胞LOVO生长都具有明显的抑制作用,并且昆布多糖硫酸酯的抗肿瘤作用强于昆布多糖。     

岩藻多糖的提取、化学改性、降血糖活性及机理研究进展

岩藻多糖(fucoidans, FU)主要来源于海洋褐藻和海洋无脊椎动物,是一种复杂的硫酸化多糖。FU主要单糖组成为岩藻糖,含有大量硫酸基团,是一种多聚阴离子同型杂多糖。FU具有广泛的潜在健康功效及治疗作用,包括抗肿瘤、调节免疫、抗病毒、降血糖等。FU的化学结构及硫酸基团含量对功能活性具有重要影响,不同提取方法影响FUs的结构组成,而化学改性可以进一步提高其生物活性。因此,本文旨在概述FU的提取、化学改性方法及降血糖活性和机理,展望了FU提取、化学改性、结构及降血糖活性及其他生物活性构效关系方面未来研究方向,为今后的加工和创新利用提供理论参考。     

功能性低分子量岩藻多糖的研究进展

低分子量岩藻多糖来源于褐藻,是一类含有硫酸基团的多糖,具有多种生物学功能,如抗凝血、抗病毒、抗血栓、抗肿瘤等功能,因此可被广泛地应用于医药、食品等领域。着重介绍了低分子量岩藻多糖的制备及其生物学功能的研究进展。     

多糖硫酸化修饰和多糖硫酸酯的研究进展

硫酸多糖是一类糖羟基上带有硫酸根的多糖,包括从植物中提取的各种硫酸多糖、肝素、天然多糖的硫酸衍生物及人工合成的各种硫酸多糖。硫酸多糖具有抗病毒、抗肿瘤、抗凝血和增强免疫等生物活性,为提高中药多糖的生物活性,可通过硫酸化修饰的方法进行结构改造,获取多糖硫酸酯。本文就多糖的硫酸化修饰方法、多糖硫酸酯的生物学活性及其影响因素、作用机制和临床应用进行了综述。     

不同硫取代度昆布多糖硫酸酯的合成及理化性质初步研究

目的:对昆布多糖进行不同硫取代度的硫酸酯化修饰,并对其产物的硫酸基含量、糖含量与分子量进行检测,为研究不同硫取代度昆布多糖硫酸酯的生物活性奠定物质基础。方法:采用氯磺酸-吡啶法对昆布多糖进行硫酸化修饰,通过改变硫酸化修饰条件,来制取不同硫酸基取代度的昆布多糖硫酸酯;利用盐酸水解-硫酸钡比浊法测定昆布多糖硫酸酯的硫酸基含量,并通过公式求得其硫取代度;用苯酚-硫酸法测定昆布多糖硫酸酯的多糖含量,并使用HPGPC法测定其分子量。结果:两种不同硫取代度昆布多糖硫酸酯的硫酸基含量分别为37.8%、45.92%,取代度分别为1.07、1.51,糖含量分别为44.52%、37.19%,分子量分别为13000、16000。结论:利用氯磺酸-吡啶法对昆布多糖进行硫酸酯化修饰,该方法可以获取不同取代度产物,酯化率高。     

海洋微生物来源的岩藻多糖降解酶

近年来研究发现,岩藻多糖及其降解产物具有多种重要的生物学活性,对岩藻多糖降解酶的关注日益增多。本文概述了海洋微生物来源的岩藻多糖降解酶的发现、活性检测方法、性质、应用等方面的研究进展。同时展望了现代组学及结构生物学技术快速发展对海洋微生物来源的新型岩藻多糖降解酶研究的推动作用。     

HILIC-ESI-HCD-MS/MS寡糖图谱分析用于海参褐藻糖胶的结构鉴定

褐藻糖胶也称为岩藻黄质、岩藻多糖、褐藻多糖,是一种硫化的多糖,常见于海参、海藻等褐藻纲及海藻类的植物中。研究发现,具有特定硫酸化结构的糖类结构域在生物功能中起着至关重要的作用。因此,对褐藻糖胶寡糖进行精细的结构表征,尤其是确定其硫酸化结构,对于理解褐藻糖胶的结构-功能关系至关重要。     

正交实验法优选香菇多糖的提取工艺及其硫酸酯化研究

目的:考察香菇多糖的提取工艺,制备香菇多糖硫酸酯。方法:采用正交试验法考察加水量、提取时间、提取温度和粒度4个因素对香菇多糖硫酸酯提取率及其中总糖含量的影响,应用硫酸法制备香菇多糖硫酸酯并对得到的成分进行鉴别。结果:通过对正交实验结果的极差分析。得出提取温度和加水量对多糖提取率影响比较著性,提取温度和提取时间对多糖含量的影响比较著性。确定香菇多糖提取的最佳工艺为:应用40倍量的水,每次提取4 h,提取温度90℃,香菇粒度为80目。制备的多糖硫酸酯中硫酸基含量为22.80%,显示了相对较强的生物活性。结论:本实验成功的确定了提取香菇多糖的最佳工艺,制备了硫酸基含量较高的硫酸酯化香菇多糖。     

响应面法优化猴头菌硫酸化多糖

[目的]为了获得猴头菌多糖的最佳硫酸化修饰条件,提高猴头菌硫酸化多糖硫酸基团的取代度。[方法]采用单因素比较氯磺酸-吡啶摩尔比、反应温度和反应时间对猴头菌硫酸化多糖取代度的影响,利用响应面法对各因素的最佳水平以及各因素之间的交互作用进一步研究。[结果]猴头菌多糖的最佳硫酸化修饰条件为:氯磺酸-吡啶摩尔比为1:4、反应温度为59℃、反应时间为2. 6 h,取代度为0. 457,与模型的预测值基本相符。[结论]响应面法优化得到猴头菌多糖的硫酸化修饰条件参数准确,该模型可以用于猴头菌多糖硫酸化修饰条件的优化。     

薤白多糖的硫酸化修饰及体外抗氧化活性

为探讨薤白多糖硫酸化修饰的最佳条件,以及硫酸化修饰提高薤白多糖活性的可能性,采用氯磺酸-吡啶法对醇沉法得到的薤白多糖和柱层析纯化的3种分级薤白多糖进行硫酸化修饰,以氯磺酸-吡啶配比、反应温度和反应时间为自变量,修饰产物的硫酸基取代度(DS)为响应值,应用响应面设计法确定硫酸化修饰的最佳条件,用H2O2/Fe2+体系法和邻苯三酚自氧化法测定修饰产物的抗氧化活性。结果表明:薤白多糖氯磺酸-吡啶法修饰的最佳条件为氯磺酸∶吡啶=1∶3,反应温度65℃,反应时间2 h,此条件下硫酸根取代度为0.470,硫酸化修饰能提高薤白多糖的体外抗氧化活性。     

Sulfated galactofucan from <Emphasis Type="Italic">Lobophora variegata</Emphasis>: Anticoagulant and anti-inflammatory properties

Sulfated polysaccharides (fucans and fucoidans) from brown algae show several biological activities, including anticoagulant and anti-inflammatory activities. We have extracted a sulfated heterofucan from the brown seaweed Lobophora variegata by proteolytic digestion, followed by acetone fractionation, molecular sieving, and ion-exchange chromatography. Chemical analyses and ¹³C-NMR and IR spectroscopy showed that this fucoidan is composed of fucose, galactose, and sulfate at molar ratios of 1:3:2. We compared the anticoagulant activity of L. variegata fucoidan with those of a commercial sulfated polysaccharide (also named fucoidan) from Fucus vesiculosus and heparin. The experimental inflammation models utilized in this work revealed that fucoidan from L. variegata inhibits leukocyte migration to the inflammation site. Ear swelling caused by croton oil was also inhibited when sulfated polysaccharides from F. vesiculosus and L. variegata were used. The precise mechanism of different action between homo-and heterofucans is not clear; nevertheless, the polysaccharides studied here may have therapeutic potential in inflammatory disorders. Published in Russian in Biokhimiya, 2008, Vol. 73, No. 9, pp. 1265–1273.     

Monthly fluctuations in the content and monosaccharide composition of fucoidan from Undaria pinnatifida sporophylls from northern Patagonia

The invasive brown seaweed Undaria pinnatifida was first recorded in 1992 in Golfo Nuevo, northern Patagonia, Argentina (hereafter Undaria). Like other brown seaweeds, Undaria synthesizes fucoidans, a unique class of sulfated polysaccharides, which display an array of biological activities and have important commercial value. In this work we have measured the content, sulfate, and monosaccharide composition of fucoidans in Undaria sporophylls from Golfo Nuevo. These results were analyzed in relation to harvest month and development stage of algal thalli. Samples were collected between November 2015 and March 2016 and classified according to morphological traits into previously defined development stages. Acid extraction (0.01 M HCl, pH 2) was carried out at room temperature and at 70 °C. Average fucoidan content was 18.1% dry wt. and slightly increased with month progression and in senescent individuals. Average sulfate content in fucoidan extracts was 20.3% dry wt. decreasing with month and development. Predominant sugars were fucose and galactose averaging a total of 91 mol% of neutral sugars. This study confirms that sporophyll fucoidans from Patagonian Undaria are sulfated galactofucans. Fucoidan content significantly increases from 14.5 to 19.2% dry wt. with sporophyte development. Slight increments with month progression are not statistically significant. Molar proportion of neutral sugars is constant between maturity stages and varies slightly with month progression. Sulfate content of fucoidan decreased significantly with development and month progression. Pooled with previous reports about abundance and seasonality of Undaria in Patagonia, our results suggest that sporophylls could be harvested for fucoidan production at least during 5 months between November and March.

     

A comparative study of the anti-inflammatory, anticoagulant, antiangiogenic, and antiadhesive activities of nine different fucoidans from brown seaweeds

The anti-inflammatory, antiangiogenic, anticoagulant, and antiadhesive properties of fucoidans obtained from nine species of brown algae were studied in order to examine the influence of fucoidan origin and composition on their biological activities. All fucoidans inhibited leucocyte recruitment in an inflammation model in rats, and neither the content of fucose and sulfate nor other structural features of their polysaccharide backbones significantly affected the efficacy of fucoidans in this model. In vitro evaluation of P-selectin-mediated neutrophil adhesion to platelets under flow conditions revealed that only polysaccharides from Laminaria saccharina, L. digitata, Fucus evanescens, F. serratus, F. distichus, F. spiralis, and Ascophyllum nodosum could serve as P-selectin inhibitors. All fucoidans, except that from Cladosiphon okamuranus carrying substantial levels of 2-O-alpha-D-glucuronopyranosyl branches in the linear (1-->3)-linked poly-alpha-fucopyranoside chain, exhibited anticoagulant activity as measured by activated partial thromboplastin time whereas only fucoidans from L. saccharina, L. digitata, F. serratus, F. distichus, and F. evanescens displayed strong antithrombin activity in a platelet aggregation test. The last fucoidans potently inhibited human umbilical vein endothelial cell (HUVEC) tubulogenesis in vitro and this property correlated with decreased levels of plasminogen-activator inhibitor-1 in HUVEC supernatants, suggesting a possible mechanism of fucoidan-induced inhibition of tubulogenesis. Finally, fucoidans from L. saccharina, L. digitata, F. serratus, F. distichus, and F. vesiculosus strongly blocked MDA-MB-231 breast carcinoma cell adhesion to platelets, an effect which might have critical implications in tumor metastasis. The data presented herein provide a new rationale for the development of potential drugs for thrombosis, inflammation, and tumor progression.     

Review: Prospects for the Use of Extracts and Polysaccharides from Marine Algae to Prevent and Treat the Diseases Caused by Helicobacter pylori

Helicobacter pylori possesses a broad spectrum of pathogenic factors that allow it to survive and colonize the gastric mucosa, and thus, the pathogenetic targets, which have the same diversity, require search for and the development of alternative, effective, and innocuous means for the eradication of H. pylori. In recent years, fucoidans have been extensively studied due to the numerous interesting biological activities, including the anti‐adhesive, anti‐oxidative, antitoxic, immunomodulatory, anticoagulant, and anti‐infection effects. This review summarizes the data on the effects of extracts and sulfated polysaccharides of marine algae, mainly fucoidans, on pathogenic targets in Helicobacter infection. The pathogenetic targets for therapeutic agents after H. pylori infection, such as flagellas, urease, and other enzymes, including adhesins, cytotoxin A (VacA), phospholipase, and L‐8, are characterized here. The main target for the sulfated polysaccharides of seaweed is cell receptors of the gastric mucosa. This review presents the published data about the pleiotropic anti‐inflammatory effects of polysaccharides on the gastric mucosa. It is known that fucoidan and other sulfated polysaccharides from algae have anti‐ulcer effects, prevent the adhesion of H. pylori to, and reduce the formation of biofilm. The authors speculate that the effect of sulfated polysaccharides on the infectious process caused by H. pylori is related to their action on innate and adaptive immunity cells, and also anti‐oxidant and antitoxic potential. Presented in the review are materials indicated for the study of extracts and sulfated polysaccharides from seaweed during H. pylori infection, as these compounds are characterized by multimodality actions. Based on the analysis of literary materials in recent years, the authors concluded that fucoidan can be attributed to the generation of new candidates to create drugs intended for the inclusion in the scheme of eradication therapy of H. pylori infection.     

Inhibition of complement activation by water-soluble polysaccharides of some far-eastern brown seaweeds

Fucoidans and laminarans from Laminaria cichorioides, Laminaria japonica, Fucus evanescens, laminaran from Laminaria gurjanovae, other beta-D-glucans (translam, pustulan and zymosan) and lambda-carrageenan from Chondrus armatus were used to study the effect of water-soluble polysaccharides from seaweeds on the alternative pathway of complement (APC). beta-D-Glucans and fucoidans under study differed appreciably from each other by structural characteristics, and also by degree of purification. beta-D-glucans, on ability to bind complement, ranked in a line according to a degree of their purification. Highly purified beta-D-glucans under study did not reveal an ability to bind complement. The fucoidans were divided conventionally into three groups according to their action on APC. Highly sulfated alpha-L-fucan from L. cichorioides with the greatest activity toward APC and caused 50% inhibition of reaction of activation (RA) of APC in a concentration of 0.5-0.7 mg/ml. Opposite 50% of inhibition of lysis of erythrocytes by sulfated heterogeneous fucoidan from L. japonica was achieved with 20 mg/ml. All other fucoidans and lambda-carrageenan have activity at 6-10 mg/ml concentration. Decreasing the sulfate content from 36% up to 9% in sample fucoidans under study was not reflected practically in the 50% inhibition concentration. Apparently, the degree of sulfating of fucoidans did not influence their action on APC. But the positive influence of fucose in structure of polysaccharide was obvious.     

Anticoagulant activity of fucoidans from brown algae

The anticoagulant activity of polysaccharide fucoidans from 11 species of brown algae was studied. The anticoagulant activity was measured by the activated partial thromboplastin time (APTT), prothrombin time, and thrombin time. Inhibitory action of these fucoidans significantly varied from one species to another. Fucoidans from Laminaria saccharina and Fucus distichus exhibited high anticoagulant activity, while fucoidans from Cladosiphon okamuranus and Analipus japonicus were almost inactive. Other fucoidans exhibited intermediate inhibitory activity. The inhibitory effect of fucoidans on thrombin and factor Xa was investigated in the presence or in the absence of natural thrombin inhibitor, antithrombin III (AT III). In contrast to the best-studied anticoagulant, heparin, most of these fucoidans inhibited thrombin in the absence of AT III. In the presence of AT III the inhibitory effect of fucoidans considerably increased. In contrast to heparin, fucoidans weakly influenced factor Xa activity in the presence of AT III and their inhibitory effect was not observed in the absence of AT III. There was no correlation between the anticoagulant activities of this series of fucoidans and their anti-inflammatory action, studied earlier. It is suggested that these two types of fucoidan activities depend on different structural features of fucoidans. Results of this study demonstrate a possibility of preparation of fucoidans with high anti-inflammatory activity but low anticoagulant activity. Anticoagulant activity of the fucoidans did not exhibit direct dependence on the content of fucose, the other neutral sugars and sulfates; no dependence was also found between the anticoagulant activity and the structure of the backbone of their molecules.     

Mild acid hydrolysis of fucoidan: characterization by electrophoresis and FT-Raman spectroscopy

Along with proteins, lipids, water and minerals, polysaccharides are the main chemical compounds of which macroalgae are built. Among the chemical compounds now widely examined is fucoidan (fucan, fucosan, sulfate fucan or sulfated fucan), a fucose-containing sulfated polysaccharide. Fucoidans isolated from different species have been extensively studied because of their varied biological properties, including anticoagulant and antitumor effects. Methodology based on mild acid hydrolysis can be used as an efficient tool to study the relationship between molecular weight of the sulfated polysaccharides and their biological activities. Anticancer activity of fucoidans can be significantly enhanced by lowering their molecular weight only when they are depolymerized under mild conditions. In this study, fucoidan was identified during extraction with H₂SO₄ and HCl; its presence was confirmed by FT-Raman spectroscopy in aqueous solution. In particular, shifts at 840 cm⁻¹ were analysed, which are due to the presence of sulfate at the axial C-4 position, as were the shifts at about 811–809 cm⁻¹, for which the sulfated fucoidan is responsible. Shifts of electrophoretic bands of fucoidan resulting from mild acid hydrolysis in H₂SO₄ and HCl were also analysed. The analytical procedure was developed using apparatus for cellulose acetate membrane electrophoresis and this was supplemented by semi-quantitative analysis.     

Polysaccharides composition from tropical brown seaweeds

Polysaccharides composition of the tropical brown seaweeds Turbinaria turbinata, Sargassum filipendula, Dictyota caribaea and Padina perindusiata collected at Yucatan Peninsula (Mexico) was determined in this study. Crude fucoidan extracted with HCl and alginate extracted with a hot alkali solution were characterized in terms of their molecular weight, sulfate content, uronic acid, total carbohydrate and neutral sugar components. Low molecular weight sulfated‐fucoidan was the major component in all species studied. Fucoidan from T. turbinata and from D. caribaea were characterized as a homofucan, with fucose as the neutral sugar. Fucoidan from S. filipendula was composed of a galactofucan, and fucoidan from P. perindusiata was characterized as a heterofucan consisting of fucose, glucose and galactose. The Fourier transform infrared (FT‐IR) spectra of fucoidan extracted from species studied indicated that the majority of sulfate groups are located at C‐4 and to a lesser extent at C‐2 and/or C‐3 of the fucopyranose residues. This could be advantageous since several therapeutic effects have been reported for fucoidans with similar characteristics. FT‐IR spectra from D. caribaea and P. perindusiata revealed the presence of O‐acetyl groups in crude fucoidan, which could be potentially utilized as an immune stimulant. Molecular weight of alginate varied between 595 and 1301 kDa with similar uronic acid content in all species. Alginate M : G ratio inferred from FT‐IR spectra suggests a high content of G‐block in all species. Potential applications of these polysaccharides are discussed.     

In Vitro Anti-influenza Virus Activities of Sulfated Polysaccharide Fractions from Gracilaria lemaneiformis

In this paper, in vitro anti-influenza virus activities of sulfated polysaccharide fractions from Gracilaria lemaneiformis were investigated. Cytotoxicities and antiviral activities of Gracilaria lemaneiformis polysaccharides (PGL), Gracilaria lemaneiformis polysaccharide fraction-1 (GL-1), Gracilaria lemaneiformis polysaccharide fraction-2 (GL-2) and Gracilaria lemaneiformis polysaccharide fraction-3 (GL-3) were studied by the Methyl thiazolyl tetrazolium (MTT) method, and the inhibitory effect against Human influenza virus H1-364 induced cytopathic effect (CPE) on MDCK cells were observed by the CPE method. In addition, the antiviral mechanism of PGL was explored by Plaque forming unit (PFU), MTT and CPE methods. The results showed: i) Cytotoxicities were not significantly revealed, and H1-364 induced CPE was also reduced treated with sulfated polysaccharide fractions from Gracilaria lemaneiformis; ii) Antiviral activities were associated with the mass percentage content of sulfate groups in polysaccharide fractions, which was about 13%, in polysaccharides (PGL and GL-2) both of which exhibited higher antiviral activity; iii) A potential antiviral mechanism to explain these observations is that viral adsorption and replication on host cells were inhibited by sulfated polysaccharides from Gracilaria lemaneiformis. In conclusion, Anti-influenza virus activities of sulfated polysaccharide fractions from Gracilaria lemaneiformis were revealed, and the antiviral activities were associated with content of sulfate groups in polysaccharide fractions.