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.     

Microwave-assisted solubilization and solution properties of hyperbranched polysaccharide

A water-insoluble hyperbranched β-d-glucan (TM3a), extracted from sclerotia of Pleurotus tuber-regium, was treated by microwave exposure to improve its solubility in water. This method led to complete dissolution of the TM3a polysaccharide in 0.02 wt % aqueous NaN₃. Various treatment periods were tested, and optimal conditions corresponded to 35 s at 765 W. The solution properties of TM3a in water were studied systematically by using size-exclusion chromatography combined with laser light scattering, viscometry, and dynamic light scattering at 25 °C. The dependences of intrinsic viscosity ([η]), radius of gyration (), and hydrodynamic radius (R_h) on weight average molecular weight (M_w) for TM3a in 0.02 wt % aqueous NaN₃ at 25 °C were found to be , , and in the M_w range from 8.20 × 10⁵ to 4.88 × 10⁶. The fractal dimension, ratio of , and the <r²>_o/M_w value of TM3a were calculated and discussed. The results indicated that TM3a existed in a sphere-like conformation in 0.02 wt % aqueous NaN₃. Furthermore, by using transmission electron microscopy, we observed directly the spherical molecules of TM3a. This work gave valuable information on improvement of solubility and chain conformation characterization of the water-insoluble polysaccharide in water.     

Immunomodulation and antitumor activities of different-molecular-weight polysaccharides from Porphyridium cruentum

The extracellular polysaccharides (EPSs) isolated from Porphyridium cruentum were degraded by hermetical-microwave and H₂O₂ under ultrasonic waves. Six products were obtained with molecular weights of 6.53, 256, 606, 802.6, 903.3 and 1002 kDa. The antitumor and immunomodulatory activities of different-molecular-weight (MW) polysaccharides were evaluated by the S180-tumor-bearing mouse model in vivo and peritoneal macrophage activation in vitro. The degraded EPSs all showed clear immunomodulation to different extents. The MW of the EPSs had a notable effect on their activity. The 6.53-kDa fragment had the strongest immunoenhancing activity. Different doses of EPS all inhibited the growth of the implanted S180 tumor. The tumor inhibition index at high, middle and low doses was 53.3%, 47.5% and 40.5%, respectively. In addition, three different concentrations of EPS significantly increased lymphocyte proliferation, which indicated the unique mechanism of the antitumor effect of EPS.     

Optimization of production conditions for mushroom polysaccharides with high yield and antitumor activity

Single factor experiment and response surface methodology were conducted to optimize the production conditions for polysaccharide with higher antitumor activity from mushroom fermentation broth. Based on the results of single factor experiments, a central composite design was applied to the following optimization and second-order polynomial regression models were established. As the yield and antitumor activity of the polysaccharides were considered with equal weight, the optimal conditions were that ethanol concentration and pH of the broth was adjusted to 85.00% and 7.70 respectively, then precipitated at 12 °C for 1 h and dried the precipitates at 40 °C. The verification experiments completed under the optimal conditions gave the polysaccharides yield of 9.843 ± 0.217 g/l, and the cancer cell growth inhibitory rate of 83.69 ± 0.167% by the polysaccharides, which were in close agreement with values predicted by the models (RSD < 5%).     

Immunopontentiating and antitumor activities of the purified polysaccharides from Phellodendron chinese SCHNEID

The polysaccharide fractions were isolated and purified from Phellodendron chinese SCHNEID, and antitumor activities were examined at dosages of 2, 5 and 10 mg/100 g. F-7 and F-8 showed the highest tumor inhibitory activities (inhibition ratio 96.4 and 98.2% in 2 mg/100 g), and in dose of 5 mg/100 g, the inhibitory ratios were 95.3 and 97.5%, respectively. Furthermore, 10 mg/100 g of intraperitoneal (i.p.) injection gave 97.3 and 98.7% of inhibition. In oral administration, the inhibitory activities were not markedly observed, indicating that the polysaccharides are directly acting to immune system. Also the polysaccharides increased the number of circulating blood leukocytes and total peritoneal exudate cells. Although implantation of tumor cells greatly decreased the productivity of antibody (antibody-mediated) and T lymphocyte reactivity (delayed-type) as 6.3 from 9.3 and 5.9 from 7.7, represented by the increase of footpad thickness, respectively. The polysaccharides elevated the reactivity of T lymphocyte in tumor-bearing mice, which were rapidly recovered by discontinuance of sample treatments. Especially, F-2, F-5, F-7 and F-8 remarkably recovered the decreased sensitivity. When the effects on thymidylate synthase (TS) and thymidine kinase (TK) activities were determined, TS activities in the F-2 and F-7-treated mice were markedly suppressed to 73.7% and 79.5% of that in the control (p < 0.01), while there was little difference in TK activity with a slight decrease in F-2 only. However, in i.p. injection, TS activities in the F-2, F-5, F-7 and F-8-treated mice were markedly suppressed to 83% to 85% of that in the control (p < 0.01). Furthermore, there were also significant differences in TK activities in F-2, F-5, F-7 and F-8-treated mice (p < 0.05). These results clearly indicated that the i.p. injection is much effective to suppress tumor growth than oral administration.     

猴头菌多糖脱色前后理化性质及生物活性的研究

以脱色前、后的猴头菌Hericium erinaceus粗多糖为研究对象,对其多糖含量、多糖中的单糖组成、分子量分布、红外光谱等理化性质和体外免疫活性、胃粘膜损伤的修复作用进行了比较研究。结果表明,猴头菌多糖脱色后,多糖含量提高、蛋白含量下降、小分子物质大量减少、单糖种类基本不变,岩藻糖所占比例略有下降、半乳糖及葡萄糖比例略有上升,红外光谱显示,脱色后多糖中的C=O基团减少;多糖脱色后体外免疫活性显著提高（P<0.05）,低浓度的未脱色多糖与模型组相比,对胃粘膜的损伤修复作用无显著性差异（P<0.05）,而低浓度的脱色多糖对胃粘膜的损伤修复作用显著提高（P<0.01）。     

Bioactivities of water-soluble polysaccharides from fruit shell of Camellia oleifera Abel: Antitumor and antioxidant activities

Polysaccharides were extracted from fruit shell of Camellia oleifera Abel. Fruit shell of Camellia oleifera Abel polysaccharide (WEP2) was a water-soluble compound. Its molecular weight was about 362 kDa. HPLC analysis showed that this polysaccharide was composed of rhamnose, fucose, arabinose, mannose, galactose and glucose in the molecular ratio of 4.05, 11.62, 1.78, 3.91, 8.76 and 27.06, respectively. The broad intense characteristic peak around 3463 cm⁻¹ due to the hydroxyl stretching vibration of the polysaccharide was observed in the polysaccharide. The characteristic absorption bands at 852 cm⁻¹ and 893 cm⁻¹ indicated that WEP2 contained both α-glycosidic and β-glycosidic linkages. WEP2 exhibited remarkable antitumor activity against Sarcoma180 cell compared to the negative control group. At the highest dose 40 mg/kg days, the tumor inhibition rate reached 65.2%. The scavenging effects of WEP2 to hydroxyl radical and superoxide radical anion were 72.5% and 86.3% at a concentration of 1.0 mg/ml, respectively.     

三个不同产地香菇多糖的理化性质及生物活性研究

本研究分析了浙江、湖北和新疆香菇多糖的结构、抗氧化及抗肿瘤活性。采用水提醇沉法,制备3个产地香菇多糖,分别利用Sevag法及透析法对其进行初步纯化,获得浙江香菇多糖（ZLP）、新疆香菇多糖（XLP）、湖北香菇多糖（HLP）。进一步通过高效阴离子交换色谱（HPAEC）测定其单糖组成,傅里叶变换红外光谱（FTIR）分析其结构。检测了3个多糖的自由基清除能力和抑制肿瘤细胞增殖能力。结果表明,3个多糖均主要由葡萄糖、半乳糖及甘露糖组成。3个多糖红外光谱的特征吸收峰相似,均含有β糖苷键。HLP、ZLP、XLP均可有效清除1,1-二苯基-2-苦基肼（DPPH）、2,2-联氮基双-3-乙基苯并噻唑啉-6-磺酸（ABTS）和羟基自由基。此外,HLP和XLP对人肝癌细胞（HpG2）、人肺癌细胞（NCI-H460）、人胃腺癌细胞（SGC-7901）的抑制增殖能力高于ZLP。     

食用菌多糖的抗氧化活性

许多食药用真菌都具有各种生理活性[1],其中多糖是最重要的生物活性成分之一,具有清除自由基、提高抗氧化酶活性和抑制脂质过氧化的活性,从而可起到保护生物膜和延缓衰老的作用,因此食用菌多糖成为保健食品和药品开发的重要来源[2]. 目前有关真菌多糖清除自由基的研究有较多的报道[3-8],一些研究认为其抗氧化活性可能与菌体的多糖含量有密切关系.本刊201 1年第10期刊登了魏磊、范黎等的论文"四种野生食用菌粗多糖的抗氧化活性"[9].     

Synthesis of phenanthroindolizidine alkaloids and evaluation of their antitumor activities and toxicities

We previously reported that phenanthroindolizidine alkaloid 3 and its derivatives had markedly potent in vitro cytotoxicity. However, they had low in vivo antitumor activities and high in vivo toxicities, which was a serious problem. To address this problem, new phenanthroindolizidine derivatives were synthesized and their antitumor activities and toxicities were evaluated. This study describes the relationship between the chemical structures, antitumor activities, and toxicities of these phenanthroindolizidine derivatives. Based on its properties, compound 8 was found to be the most suitable potential antitumor agent.     

Preparation and anticoagulant activity of a low-molecular-weight sulfated chitosan

Synthesis of chitosan sulfates with low molecular weight (M_v 9000–35,000 Da) was carried out by sulfation of low molecular weight chitosan (M_v 10,000–50,000 Da). The oleum was used as sulfating agent and dimethylfornamide as medium. The chitosans were prepared by enzymatic and acidic hydrolysis of initial high molecular weight chitosan as well as by extrusion solid-state deacetylation of chitin. As was shown by FT-IR and NMR-methods and elemental analysis, the sulfation occurred at C-6 and C-3 positions and substitution degree is 1.10–1.63. The molecular weight sulfated chitosan was determined by viscometric method and the Mark–Houwink equation [η]=10⁻⁵ 4.97 M^0.77. Study of anticoagulant activity showed that chitosan sulfates with lowered molecular weight demonstrated a regular increase of anti-Xa activity like heparins.     

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.     

Concise synthesis and antitumor activities of trisaccharide steroidal saponins

The naturally derived trisaccharide steroidal saponin 1 and structurally modified derivatives 2 and 3 bearing the same sarsasapogenin aglycon were synthesized concisely via a direct transglycosylation strategy. The antitumor activities of the synthetic trisaccharide saponins 1–3 and their corresponding α-isomers 1a–3a were preliminarily evaluated against human gastric adenocarcinoma cell (MKN-45) and human epithelial cervical cancer cell (HeLa) by CCK-8 assay.     

Antioxidant and immunological activities of water-soluble polysaccharides from Aconitum kusnezoffii Reichb

Aconitum kusnezoffii Reichb., one of the earliest recorded toxic species of genus Aconitum, has been used as traditional Chinese medicine and medicinal diet over the last 2500 years to treat heart failure congestion, neuralgia, rheumatism and gout, etc. In the present paper, four water-soluble polysaccharide fractions isolated from the tubers of A. kusnezoffii Reichb. were studied the antioxidant and immunological activities for the first time. In vitro antioxidant assays indicated that fraction WKCP-A had noticeable scavenging activities on DPPH radical, hydroxyl radical, superoxide anion, H₂O₂ and self-oxidation of 1,2,3-phentriol, ferrous ion-chelating ability and reducing power. Moreover, the in vivo immunological assay exhibited that fractions WKCP-A and WKHP could more significantly enhance splenic lymphocyte proliferation and macrophage phagocytosis than other fractions. Therefore, the water-soluble polysaccharides from A. kusnezoffii Reichb., especially WKCP-A, have the potential to be explored as novel natural antioxidants and immunostimulating agents for using in functional foods or medicine.     

天然多糖羧甲基化对其生物活性影响的研究进展

多糖由于具有抗氧化、抗肿瘤、调节免疫、降血糖等生物活性而受到诸多领域的关注。多糖的结构与其生物活性相关,经过化学修饰会增强其生物活性或产生新的活性。本文就天然多糖的羧甲基化修饰及对其生物活性的影响进行综述,以期为多糖的研发与应用提供理论参考。     

The antitumor and antioxidative activities of polysaccharides isolated from Isaria farinosa B05

The water-soluble intra-polysaccharides WIPS1 and water-soluble extra-polysaccharides WEPS1 were isolated from Isaria farinosa B05 through ethanol precipitation and gel permeation chromatography (GPC). Their characteristics were determined by chemical analysis, gas chromatography, GPC and IR spectroscopy. The results show that WIPS1 contained 90.3% carbohydrate, 8.00% uronic acid, 7.15% protein and three kinds of monosaccharides including mannose, galactose and glucose with a molar ratio of 8.0:4.8:1.0. WEPS1 contained 93.4% carbohydrate, 8.06% uronic acid, 4.40% protein and three kinds of monosaccharides including mannose, galactose and glucose with a molar ratio of 21.6:4.7:1.0. WIPS1 and WEPS1 had a molecular weight of 42 and 208kDa, respectively. The in vivo tests in mice indicate that WIPS1 and WEPS1 had significant antitumor and antioxidative activities to some extent.     

Antioxidant activities of sulfated polysaccharides from brown and red seaweeds

The in vitro antioxidant activities of the following six sulfated polysaccharides were investigated: iota, kappa and lambda carrageenans, which are widely used in the food industry, fucoidan (homofucan) from the edible seaweed Fucus vesiculosus and fucans (heterofucans) F0.5 and F1.1 from the seaweed Padina gymnospora. With respect to the inhibition of superoxide radical formation, fucoidan had an IC₅₀ (the half maximal inhibitory concentration) of 0.058 mg·mL⁻¹, while the IC₅₀ for the kappa, iota and lambda carrageenans were 0.112, 0.332 and 0.046 mg·mL⁻¹, respectively. All of the samples had an inhibitory effect on the formation of hydroxyl radicals. The results of peroxidation tests showed that fucoidan had an IC₅₀ of 1.250 mg·mL⁻¹ and that the kappa, iota and lambda carrageenans had an IC₅₀ of 2.753 and 2.338 and 0.323 mg·mL⁻¹, respectively. Fucan fractions showed low antioxidant activity relative to fucoidan. These results clearly indicate the beneficial effect of algal polysaccharides as antioxidants.     

Structural studies of water-soluble polysaccharides of an edible mushroom, Termitomyces eurhizus. A reinvestigation

The structure of two polysaccharides isolated from the hot aqueous extract of fruiting bodies of the mushroom, Termitomyces eurhizus, have been reinvestigated. These consist of two homogeneous fractions PS-I and PS-II. PS-I contains only D-glucose as the monosaccharide constituent. From methylation analysis and periodate oxidation studies, followed by GLC-MS analysis the linkages, the sugar units in PS-I were identified as (1-->3)-D-Glcp and (1-->6)-D-Glcp. PS-II contains D-glucose, and the mode of linkage of d-glucose was identified as (1-->6)-D-Glcp. Finally, the following possible structures of the polysaccharides were assigned using 1H, 2D-COSY, TOCSY, NOESY and 13C NMR spectral analysis: [carbohydrate structure: see text].