香菇不同发育阶段子实体多糖的理化性质及体外免疫活性研究

香菇多糖是从香菇菌丝体或子实体中提取纯化得到的高分子葡聚糖,作为香菇主要的生物活性物质,具有提高免疫力、抗病毒、抗氧化和抗真菌等生物活性。本研究对幼菇期、菌褶期、采收期、成熟期和开伞期5个不同发育阶段香菇粗多糖含量、理化性质和体外免疫活性进行比较分析。结果表明,其粗多糖含量、理化性质和体外免疫活性具有明显差异。粗多糖得率呈现先增加后降低的趋势,菌褶期得率最高;粗多糖含量也呈现先增加后降低的趋势,成熟期含量最高;多糖的分子量因发育期不同而有较大差异,发育后期所得粗多糖分子量千万级以上组分的比例增加,分子量百万级和十万级的多糖组分比例降低;不同发育阶段香菇子实体多糖的单糖组成均包含果糖、半乳糖、葡萄糖和甘露糖4种单糖,且都以葡萄糖为主;5个阶段的多糖组分均有较好的体外免疫活性,其中幼菇期粗多糖在浓度500μg/mL时表现出最高的体外免疫活性。本研究探讨了香菇不同发育阶段子实体多糖的理化性质及体外免疫活性,为香菇采收期的确定及香菇多糖的制备与利用提供理论依据。     

香菇多糖硫酸化衍生物的制备及其结构分析

采用改良的Ｗｏｌｆｒｏｍ方法制备了一系列的硫酸化香菇多糖衍生物。硫酸基含量测定结果表明,硫酸基的取代程序受反应时间和酯化试剂中氯磺酸与吡啶的比例的控制;证明甲基化分析方法不适合硫酸化香菇多糖衍生物的结构分析,＾１３Ｃ－ＮＭＲ数据表明,硫酸基取供在香菇多糖中Ｃ－６上,表明Ｃ－６位羟基的反应活性高于其他位置的羟基。     

不同分子量菊芋多糖的生物活性研究

研究不同醇沉组份的菊芋多糖分子量和其抑制α-葡萄糖苷酶活性与抗氧化活性差异。菊芋水提物分级醇沉获得粗多糖,过Sephadex G-50凝胶柱进行纯化,得到重均分子量为1959、2180、2746、2011 Da的多糖组分:JAP-1、JAP-2、JAP-3和JAP-4。测定这些组分体外抑制α-葡萄糖苷酶活性和对DPPH与羟基自由基清除能力。结果表明,JAP-4具有较明显的抑制α-葡萄糖苷酶活性,在5 mg/mL时抑制率为20.32%。JAP-1、JAP-2、JAP-3和JAP-4均有显著的抗氧化活性,其中JAP-2对DPPH自由基和羟基自由基的清除活性优于其他组分。JAP-2在2 mg/mL时对DPPH自由基和羟基自由基清除率分别达到84.50%和89.74%,接近于Vc的抗氧化活性。不同分子量菊芋多糖的活性存在差异,可能是由于分子量的不同所导致。     

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。     

海洋来源硫酸多糖体外抗氧化活性作用的初步研究

利用不同极性的溶剂提取、分离并检测裙带菜、紫菜、羊栖菜、糙海参这四种海洋生物的多糖类抗氧化活性物质,以期筛选出具有显著体外活性的海洋来源抗氧化剂。采用过氧化值(POV)、稳定自由基(DPPH·)、多酚氧化酶(PPO)、超氧阴离子自由基(O■)四种体外筛选方法表征不同来源硫酸多糖产物的抗氧化活性。结果显示,四种硫酸多糖可显著抑制猪油的过氧化,并可清除自由基和超氧阴离子,抑制多酚氧化酶的活性,抗氧化活性呈现出一定的浓度依赖性,显示了不同程度的抗氧化作用。这四种硫酸多糖具有发展为天然高效抗氧化剂的潜力。     

香菇多糖体内抗氧化活性研究

目的：探究香菇多糖的体内抗氧化活性。方法：以灌胃生理盐水的小鼠为正常对照组,将香菇多糖药物组分为低、中、高3种剂量组。小鼠在灌胃3w后,由眼眶取血,按照试剂盒要求测定小鼠血清中超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH-Px）活力以及丙二醛（MDA）含量。结果：香菇多糖可显著提高小鼠血清中SOD和GSH-Px的活力,同时减少血清中MDA含量。结论：香菇多糖对小鼠体内抗氧化活性的提高具有显著作用。     

鸡腿蘑胞外多糖的形貌结构及分子量动态变化与抗氧化的相关性研究

对鸡腿蘑多糖的结构进行检测,并在此基础上探讨结构与活性的关系,对深度发掘鸡腿蘑多糖的功效具有重要意义。制备发酵时间为72 h、96 h和120 h的鸡腿蘑胞外粗多糖,采用PMP柱前衍生化-HPLC法分析其单糖组成,结果表明发酵72 h、96 h和120 h胞外多糖均由D-甘露糖、L-鼠李糖、D-葡萄糖、D-半乳糖、D-阿拉伯糖组成,但各单糖的相对摩尔比不同。采用扫描电子显微镜和原子力显微镜对不同发酵时间的多糖形貌结构进行分析,结果显示发酵120 h多糖的板状结构更加规则,多糖分子的聚集作用更强。采用高效凝胶过滤色谱法对不同发酵时间的鸡腿蘑胞外多糖的分子量分布情况进行分析,结果显示发酵120 h的多糖分子量更大,分布范围更广。体外抗氧化试验结果显示,在相同浓度下,发酵120 h多糖的抗氧化活性较发酵72 h和96 h的多糖强。研究结果表明鸡腿蘑胞外多糖的抗氧化活性可能与其形貌结构和分子量分布有关。     

多糖硫酸酯化修饰及其抗凝血作用研究进展

硫酸多糖是一种单糖分子上的一个或多个羟基被硫酸根取代的多糖,近年来由于其良好的抗凝血活性及其较低的副作用被人们所关注.硫酸多糖包括天然硫酸多糖和化学法硫酸化多糖两种,研究证实两者都具有较好的抗凝血活性.对于硫酸多糖的抗凝血活性的构效关系的研究是改进其功能性质的核心,也是国内外研究的热点.本文综述了硫酸多糖的硫酸化方法,硫酸多糖的抗凝血活性以及机理,并对硫酸多糖的研究方向进行了展望.     

过硫酸化岩藻多糖硫酸酯

岩藻多糖硫酸酯(fucoidan或fucan sulfate,FS)是一种硫酸多糖,具有多种生物活性。硫酸基团对多糖活性起重要作用,并且多糖活性与硫酸基团含量呈正相关。近些年,国内外研究者对SF进行硫酸化修饰以获得高硫酸基团含量和高活性的过硫酸化岩藻多糖硫酸酯。为促进对FS硫酸化修饰的深入了解,本文对FS活性与硫酸基团含量及位置的关系、过硫酸化方法及过硫酸化岩藻多糖硫酸酯活性的研究进展进行了综述。     

不同品种黄麻叶多糖的理化特征及抗氧化活性研究

为提高黄麻的综合开发价值,利用热水浸提-醇沉法提取不同品种黄麻叶多糖,并对多糖的含量、结构、单糖组成、分子量以及羟基自由基、超氧阴离子自由基、DPPH自由基的清除率分别采用硫酸-苯酚法、FT-IR光谱法、水解衍生-HPLC法、凝胶渗透色谱法、水杨酸法、邻苯三酚法、二苯代苦味酰肼自由基法进行理化特征及抗氧化活性进行研究。结果表明:圆果种黄麻叶多糖的含量为80.92 mg/g,单糖组成主要为半乳糖(27.06%),分子量为59.87 kDa;长果种黄麻叶多糖的含量为60.77 mg/g,单糖组成主要为葡萄糖(44.55%),分子量为102.54 kDa;红外光谱显示此两种黄麻叶多糖结构出现相似吸收峰,均具有多糖类物质的典型特征;在多糖浓度为1 mg/mL时,圆果种黄麻叶多糖对羟基自由基、DPPH自由基、超氧阴离子自由基清除率分别为46.23%、67.30%、75.02%,长果种黄麻叶多糖相应清除率分别为41.81%、61.11%、66.81%;圆果种黄麻叶多糖对自由基清除能力的EC_(50)均低于长果种黄麻叶多糖。两种黄麻叶多糖具有一定的抗氧化能力,是潜在的抗氧化活性物质药用资源。     

Study of antioxidant activities of sulfated polysaccharides from Laminaria japonica

The composition, molecular weight and in vitro antioxidant activity of various sulfated polysaccharides obtained by anion exchange chromatography, acid hydrolysis and radical process degradation of the crude sulfated polysaccharide extracted from Laminaria japonica were compared. The low sulfated F-A2, with a peak-molecular weight (Mp) of 5–15 kDa, 14.5% sulfated ester and 21.8% glucuronic acid, exhibited a very strong antioxidant activity on superoxide and hydroxyl radicals, with activity even higher than that of large molecular weight fractions F-A and F-B. However, highly sulfated fractions with a peak-molecular weight below 15 kDa had much lower antioxidant activities than other fractions. These results indicated that the sulfate group of the low molecular weight fractions represents a physical block for the reaction with oxygen radicals. The chemical properties and antioxidant activities of sulfated polysaccharide fractions obtained by radical process degradation of crude sulfated polysaccharide were quite different from those obtained by acid hydrolysates. By radical process degradation, the high molecular weight was decreased to give LM2 (Mp 8 kDa) and LM1 (Mp 1.5 kDa), with a yield of 40% and 15%, respectively. LM2 was enriched with fucose and sulfated ester, while containing low amounts of glucuronic acid. The antioxidant activity showed that LM2 was unable to scavenge either superoxide or hydroxyl radical, which suggested that radical process degradation targeted mainly ascopyllan-like species rich in glucuronic acid, while the fraction rich in sulfated l-fucose remained unchanged. However, LM1 with Mp 1.5 kDa still retained apparent scavenging ability for superoxide radical, although it contained no glucuronic acid and certain amounts of galactose and mannose as main neutral sugars. These result suggest that the antioxidant activity of sulfated polysaccharides is apparently related not only to molecular weight and sulfated ester content, as previously determined, but also to glucuronic acid and fucose content.     

Physicochemical properties and antitumor activities for sulfated derivatives of lentinan

Five fractions of lentinan, a β-(1→3)-d-glucan bearing β-(1→6)-d-glucopyranosyl branches, were treated with chlorosulfonic acid for 90 min at 60 °C in pyridine medium to synthesize water-soluble sulfated derivatives having the substitution degree of 1.44–1.76. The ¹³C NMR spectra of the sulfated β-glucans indicated that the C-6 position was preferentially substituted by the sulfate groups. The values of the weight-average molecular weight (M_w), radius of gyration (), and intrinsic viscosity ([η]) of the sulfated lentinan fractions were determined by size-exclusion chromatography with multi-angle laser light scattering (SEC–MALLS) and viscometry in 0.15 M aq NaCl at 25 °C, respectively. The dependence of [η] on M_w for the sulfated lentinan was found to be [η] = 8.93 × 10⁻³ (mL/g) in 0.15 M aq NaCl (for M_w ranging from 14.6 × 10⁴ to 50.4 × 10⁴). On the basis of the Yamakawa–Fujii–Yoshizaki (YFY) theory, the conformational parameters of the sulfated lentinan were calculated as 950 nm⁻¹ for the molar mass per unit contour length (M_L), 4.8 nm for the persistence length (q), and 13.9 for the characteristic ratio (C_∞), indicating relatively extended single flexible chains in solution. The sulfated glucan fractions exhibited in vitro antiproliferative activities against sarcoma 180 (S-180) cells, and their inhibition ratios were lower than that of the triple-helix lentinan, but higher than that for the one with single random-coil lentinan chains.     

Catalytic synthesis and antioxidant activity of sulfated polysaccharide from Momordica charantia L.

Sulfated derivatives of polysaccharide from Momordica charantia L. (MCPS) with different degree of sulfation (DS) were synthesized by chlorosulfonic acid method with ionic liquids as solvent. Fourier transform infrared spectra and ¹³C nuclear magnetic resonance spectra indicated that C‐6 substitution was predominant in MCPS compared with the C‐2 position. Compared with the native polysaccharide from Momordica charantia L. (MCP), MCPS exhibited more excellent antioxidant activities in vitro, which indicated that sulfated modification could enhance antioxidant activities of MCP. Furthermore, high DS and moderate molecular weight could improve the antioxidant activities of polysaccharide. © 2013 Wiley Periodicals, Inc. Biopolymers 101: 210–215, 2014.     

Separation,purification and preliminary characterization of sulfated polysaccharides from Sargassum plagiophyllum and its in vitro anticancer and antioxidant activity

Sulfated polysaccharides (SPs) were identified in different portions of the thallus of Sargassum plagiophyllum C. Agardh, with TBO staining. SPs were extracted using a blade and purified by Q sepharose fast flow anion-exchange chromatography, resulting in SP fractions F1, F2 and F3, with molecular weights of 30, 35 and 20 kDa, respectively. An SP yield of 43.1% was obtained in F3, while F2 yielded a sulfate content of 21.9%. Furthermore, the in vitro anticancer and antioxidant activities of the polysaccharide fractions were evaluated. The F2 fraction showed higher anticancer activity against HepG2 and A549 cells than the other two fractions, with IC₅₀ values of 600 μg/mL and 700 μg/mL, respectively. The normal breast epithelial cell line (HBL-100) exhibited IC₅₀ concentrations of 1200 and 1400 μg/mL for crude sulfated polysaccharides (CSPs) and all SP fractions (F1–F3). These results indicated that the anticancer activity of F2 could be related to its sulfate content. However, the antioxidant activities of F1–F3 were low at their tested concentrations.     

Binding of heparin fractions and other polysulfated polysaccharides to plasma fibronectin: effects of molecular size and degree of sulfation of polysaccharides

Heparin was divided into four fractions on fibronectin-Sepharose. The higher affinity fraction for fibronectin was larger in molecular size, higher in sulfate content and higher in affinity for anti-thrombin III. Together with these heparin fractions, the following three series of heparin samples were examined to compare the affinity for fibronectin-Sepharose: four fractions separated on Sephadex G-100; five fractions separated on antithrombin III-Sepharose, and six partially and completely N-desulfated heparins. The result showed that the affinity of heparin for fibronectin was dependent exclusively on its molecular size, and that an appropriate level of sulfate content in heparin (1.9-2.4 mol/disaccharide) was essential for the affinity. The sulfated preparations of glycosaminoglycans (heparan sulfate, dermatan sulfate and chondroitin 4-sulfate) and neutral polysaccharides (amylose and dextran) having higher sulfate content than heparin were found to display higher affinity for fibronectin than heparin. This suggested that highly sulfated polysaccharides showed potent affinity irrespective of their polysaccharide structure. The sulfated chondroitin 4-sulfate having a sulfate content and molecular size comparable to those of heparin was inferior to heparin with respect to affinity. A competitive dissociation experiment indicated that heparin and other polysulfated polysaccharides share a common binding site on the fibronectin molecule.     

Sulfated modification and antioxidant activity of exopolysaccahrides produced by Enterobacter cloacae Z0206

Nine modification conditions were designed to sulfate exopolysaccharides (EPS) produced by Enterobacter cloacae Z0206 by chlorosulfonic acid-pyridine (CSA-Pyr) method according to the orthogonal test and focusing on three affecting factors such as the ratio of CSA to Pyr, reaction temperature and reaction time. And nine sulfated derivatives with various degrees of substitution (DS) were obtained. Their antioxidant activities were evaluated in vitro, by scavenging abilities on superoxide radical and hydroxyl radical. The results indicated that sulfated derivatives of EPS showed noticeable effects on scavenging superoxide radical and hydroxyl radical compared with native one, and sulfated derivative with moderate DS of 0.60 showed highest antioxidant activities. The optimum sulfated conditions of EPS were the ratio of CSA to Pyr of 1:2, the reaction time of 2h and reaction temperature of 70 °C.     

Antioxidant activities of sulfated polysaccharide fractions from Porphyra haitanesis

Three sulfated polysaccharide fractions (F1, F2, and F3) were isolated from Porphyra haitanesis, an important economic alga in China, through anion-exchange column chromatography and their in vitro antioxidant activities were investigated in this study. Galactose was the main sugar unit of the three fractions. The analytical results indicated that polysaccharide fractions from P. haitanesis had similar chemical components to porphyran from other species, but differed in their high sulfate content. The sulfate content of F1, F2 and F3 was 17.4%, 20.5% and 33.5% respectively. All three polysaccharide fractions showed antioxidant activities. They had strong scavenging effect on superoxide radical, and much weaker effect on hydroxyl free radical. Lipid peroxide in rat liver microsome was significantly inhibited, and H₂O₂ induced hemolysis of rat erythrocyte was partly inhibited by F1, F2 and F3. Among them, F3 showed strongest scavenging effect on superoxide radical; F2 had strongest effect on hydroxyl radical and lipid peroxide.     

Antioxidant activity of sulfated polysaccharide fractions extracted from Laminaria japonica

Fucoidan, a group of sulfated heteropolysaccharide, was extracted from Laminaria japonica, an important economic alga species in China. Three sulfated polysaccharide fractions (F1, F2, and F3) were successfully isolated through anion-exchange column chromatography and had their antioxidant activities investigated employing various established in vitro systems, including superoxide and hydroxyl radical scavenging activity, chelating ability, and reducing power. Chemical analysis suggested that F1 and F3 were heteropolysaccharide in which galactose was the major component, while F2 was a typical fucoidan. All fractions possessed considerable antioxidant activity, and F1, F2 and F3 had stronger antioxidant ability than fucoidan in certain tests. The correlation between the sulfate content and scavenging superoxide radical ability was positive. Available data obtained with in vitro models suggested that the ratio of sulfate content/fucose was an effective indicator to antioxidant activity of the samples.     

Correlation between antitumor activity, molecular weight, and conformation of lentinan

A (1-->3)-beta-D-glucan having (1-->6) branching (L-FV-IB) from Lentinus edodes in water was degraded into seven fractions of different molecular weights by ultrasonic irradiation, and each was further fractionated into three parts, by precipitation from water into acetone at room temperature. The weight-average molecular weight (M(w)), radius of gyration ((z)(1/2)), and intrinsic viscosity ([eta]) of lentinan and its fractions in 0.9% NaCl aqueous solution and dimethyl sulfoxide (Me(2)SO) were determined by size-exclusion chromatography combined with multi-angle laser light scattering (SEC-LLS), LLS, and viscometry. Analysis of M(w), [eta], and (z)(1/2) in terms of known theory for worm-like chains yielded 2240 +/- 100 nm(-1), and 100 +/- 10 nm for molar mass per unit contour length (M(L)), and persistence length (q), respectively, corresponding with theoretical data for triple-helical chains. The [alpha](D) of lentinan in water-Me(2)SO mixtures indicated an order-disorder transition. The results indicated that lentinan exists as a triple helix in 0.9% NaCl aqueous solution and as a single flexible chain in Me(2)SO. Assays in vivo and in vitro against the growth of Sarcoma 180 solid tumor as well as the colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method for lentinan showed that the triple-helix sample exhibited a relatively high inhibition ratio. Interestingly, the triple-helix lentinan with M(w) of 1.49 x 10(6) exhibited the highest antitumor activity in vivo, having an inhibition ratio (xi) of 49.5%, close to that of 5-fluorouracil (xi = 50.5%), whereas the bioactivity (xi = 12.3%) of its single flexible chains almost disappeared. The triple-helix conformation plays an important role in enhancing the antitumor effects of lentinan.