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1.
对南海石珊瑚Di ploria strigosa中一株共生放线菌ZJG1进行发酵,采用热水提取、乙醇沉淀、Sevag法脱蛋白、乙醇分级沉淀分离的方法提取纯化多糖,采用苯酚-硫酸法测定多糖含量,并以Vc为对照,采用DPPH清除法研究多糖对自由基的清除作用.结果表明,放线菌ZJG1多糖总提取率为12.70%,乙醇分级沉淀下...  相似文献   

2.
化橘红水溶性多糖的化学及体外抗氧化活性的研究   总被引:8,自引:0,他引:8  
化橘红粗粉经热水提取、乙醇沉淀、Sevage法脱除蛋白、CTAB(溴化十六烷基三甲胺 )配合法进一步分离纯化得化橘红多糖 ( ECP)。经 Saphadex- 2 0 0凝胶柱层析 ,硫酸 -酚法证实 ECP为均一多糖组分。气相色谱分析表明 ECP含有 D-木糖、D-葡萄糖、D-半乳糖、L-阿拉伯糖、D-甘露糖和一个未知物 (待定 ) ,它们的摩尔比为 1∶ 3.1∶ 3.6∶ 2 .8∶ 1 .8∶ 3.9。红外光谱分析表明 ECP具有典型的多糖吸收峰 ,并具有 α-构型糖苷键。紫外光谱显示在 2 60 ,2 80 nm处未见有核酸和蛋白质特征吸收峰。该多糖体外可清除邻苯三酚自氧化体系产生的超氧阴离子自由基 ( SAFR) ,且呈剂量依赖关系。结果表明 ECP为一杂多糖 ,体外有直接清除 SAFR的抗氧化活性  相似文献   

3.
银杏外种皮经乙醚脱脂后,用热水抽提,D900大孔弱碱阴离子交换树脂脱色提纯,浓缩后,乙醇沉淀得银杏外种皮粗多糖。银杏外种皮多糖具有抗癌、提高免疫力、降血脂、止咳祛痰等功能,所以利用银杏外种皮多糖可以配制抗癌的药品和保健食品,具有开发和应用前景。  相似文献   

4.
银杏外种皮经乙醚脱脂后,用热水抽提,D900大孔弱碱阴离子交换树脂脱色提纯,浓缩后,乙醇沉淀得银杏外种皮粗多糖。银杏外种皮多糖具有抗癌、提高免疫力、降血脂、止咳祛痰等功能,所以利用银杏外种皮多糖可以配制抗癌的药品和保健食品,具有开发和应用前景。  相似文献   

5.
黄芪经沸水浴提取、用Sevag法去蛋白纯化、经50%乙醇多糖分级、离心,得沉淀即H_1,浓缩上清液,沉淀即H_2;对H_1进行化学修饰得甲基化多糖;用DPPH·法对三种多糖进行抗氧化性测试,三种多糖抗自由基能力:H_2甲基化多糖H_1。它们对自由基的清除作用与其浓度呈正相关性。用水煮醇沉法提取多糖,并进行分级和化学修饰,来研究它们对自由基的清除作用,为更好地研究黄芪药用机理,扩大黄芪资源综合利用提供依据。  相似文献   

6.
茶多糖的纯化工艺研究   总被引:1,自引:0,他引:1  
邵立平 《广州化工》2010,38(4):118-119,122
实验研究了茶多糖的提取纯化工艺,主要考察醇沉、除蛋白、脱色工艺条件,得适宜的纯化工艺:提取液浓缩至1/4倍体积后,加入4倍体积95%乙醇沉淀6h,离心得茶多糖粗品。多糖粗品溶于水,并用Sevag法去除蛋白质,多糖溶液与Sevag试剂比为4:1,析出的蛋白质离心除去。清液最后经非极性大孔吸附树脂ADS-8脱色,冷冻干燥得到茶多糖制品,多糖含量65%,产率2.05%。  相似文献   

7.
采用大孔吸附树脂优化无花果多糖的脱色工艺。以无花果干果为原料,热水浸提得无花果多糖粗提物,经Sevage试剂去蛋白、乙醇沉淀后冻干得粗多糖粉末。以脱色率和多糖保留率为考察指标,筛选适合无花果多糖脱色的最优树脂和最佳的脱色工艺条件。结果表明,无花果多糖脱色的最优树脂为LSD-296,最佳脱色工艺条件为:树脂用量2.0g、多糖溶液浓度4 mg·mL~(-1)、pH值6、脱色温度40℃,为无花果多糖进一步分离纯化奠定了基础。  相似文献   

8.
选择超声波水提-醇沉法提取党参多糖,通过单因素实验和正交实验确定党参多糖的最佳提取工艺如下:党参干燥粉碎过60目筛,先后经石油醚、80%乙醇回流,挥干溶剂后,在提取温度为60℃、料液比为1∶12(g∶mL)、超声波功率为70%、提取时间为45min的条件下提取2次,党参多糖的提取率达到13.57%。对提取的党参多糖进行了抗氧化性研究,结果表明,当党参多糖浓度为0.4545μg·mL-1时,对羟自由基的清除率达到59.04%。  相似文献   

9.
2-乙氧基-4-氨基苯酚合成的新方法   总被引:1,自引:0,他引:1  
以邻苯二酚和乙醇为原料,通过取代、硝化反应先制得2-乙氧基-4-硝基苯酚;然后在钯碳催化剂作用下进行加氢反应制得2-乙氧基-4-氨基苯酚粗品;粗产物用苯-石油醚进行重结晶得到纯品。产品总收率为60·5%。  相似文献   

10.
在单因素试验基础上用响应面法对油茶叶多糖的闪式提取工艺进行优化,并对较优条件下提取的多糖的抗氧化活性进行测试。研究结果表明:油茶叶多糖闪式提取的较佳工艺条件为料液比1:30(g:mL),提取温度81℃,提取时间75 s,此条件下,油茶叶多糖得率为8.43%。油茶叶多糖对DPPH·、·ABTS+、OH·都有很强的清除能力,其半数抑制浓度(IC50)值分别为1.706、0.826和4.811 g/L,表现出很好的抗氧化活性。  相似文献   

11.
考察了三白草乙醇提取物经不同溶剂萃取所得的各部分对1,1-二苯基-2-三硝基苯肼(DPPH)自由基、羟基自由基和超氧自由基的清除能力。以2,6-二叔丁基-4-甲基苯酚(BHT)为参考。结果表明,三白草乙醇提取物经不同溶剂萃取所得的各部分对DPPH自由基、羟基自由基和超氧自由基都具有清除能力,且随着提取物浓度的增加,清除能力逐渐增高;其中乙酸乙酯部分对DPPH自由基、羟基自由基和超氧自由基的清除作用最强。  相似文献   

12.
紫荆花黄酮类化合物体外抗氧化活性研究   总被引:1,自引:0,他引:1  
采用Fenton反应体系产生羟自由基和邻苯三酚自氧化产生超氧阴离子自由基,研究了紫荆花黄酮类化合物对两者的清除作用。并以芦丁为对照品,测定了其总黄酮含量。结果表明:紫荆花中总黄酮含量为9.094 mg/g。紫荆花黄酮类化合物对羟自由基和超氧阴离子自由基均有清除作用,其浓度的添加量在试验范围内与其抗氧化活性呈正相关。紫荆花黄酮类化合物对羟自由基半数清除量(IC50)为127.822μg/mL。  相似文献   

13.
In this study self‐supporting, resilient, load bearing polybutadiene ‐ soybean oil gels were obtained. The gels were made by dissolving polybutadiene (PBD) in soybean oil (SO) and selectively crosslinking PBD with a free radical source. PBD concentration, free radical source concentration, and the temperature and time of the crosslinking reaction were varied, and the effects of these changes on the mechanical properties of the gels were examined. Our experiments show that successful gelation is possible within PBD concentration limits of 7.5 to 12%, peroxide concentration between 25 to 100% (based on PBD), temperature between 110°C and 130°C and reaction times of 3 hours with tert.butyl‐peroxybenzoate as the free radical source. The crosslinking reaction was followed by IR and H‐NMR spectra, and the crosslinking density was followed by compression testing and swelling behavior. Higher radical source concentration and higher PBD concentration gave gels with better mechanical properties. The spectra and the viscosity increase of SO extracted from the gels indicate that there is dimer and trimer formation of SO during the reaction. The spectra of the PBD extracted from gels indicate that SO was added to PBD in a small but measurable amount. Integration of peak intensities in the NMR spectrum of methylene groups of PBD and methylene groups of triglyceride indicated one triglyceride molecule for approximately 45 repeating units in PBD. The modulus of the best gel sample (PBD 10%. peroxide 50%) was 1.96 × 10?2 MPa. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2240–2246, 2005  相似文献   

14.
不同预处理方法对稻秸纤维表面性质的影响   总被引:1,自引:0,他引:1  
通过对稻秸原料进行水热、酸碱和冷等离子体预处理,分析了纤维表面的浸润性及表面自由基浓度的变化。研究表明,经水热及酸碱预处理后,纤维与水的接触角为90o,稻秸纤维的浸润性改善不明显,经冷等离子改性后,稻秸纤维表面浸润性改善非常明显。水热及乙酸处理有利于提高稻秸纤维的表面自由基浓度,碱处理则降低了稻秸纤维的表面自由基浓度。  相似文献   

15.
A new dinitroxide (1,4‐di (1‐oxy‐2,2,6,6‐tetramethyl‐1‐piperidin‐4‐yl)‐xylene) (DTPX) was synthesized and successfully used in stable free radical polymerization of styrene. The results of the polymerizations showed that the DTPX was a suitable mediating agent for stable free radical polymerization of styrene. However, it was found that the dinitroxide mediating process resulted in a higher level of decomposition of the internal bisalkoxyamine linkage in the polymer chain, which resulted in polymers possessing a terminal alkoxyamine and an adjacent hydroxylamine, and the decomposition became more obvious at high conversion through monitoring the change of molecular weights with the conversion by gel permeation chromatography and the polymer structure by 1H‐NMR. The reaction temperature showed obvious effects on the polymerization, and the polymerization of styrene at 110°C led to a better controlled polymerization than that at 125°C with narrower molecular weight distributions and slight decomposition of the nitroxide up to monomer conversions of 76.7%, however, the rate of the polymerization was decreased and an induction period appeared at 110°C. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1137–1145,2006  相似文献   

16.
N‐Benzyl‐3‐methylenepyrrolidin‐2‐one ( 3 ) was synthesized and homopolymerized under free radical conditions. The configurational microstructure of poly(N‐benzyl‐3‐methylenepyrrolidin‐2‐one) ( 4 ) is isotactic with a minor tendency to syndiotacticity. Monomer 3 was also homopolymerized in water in the presence of methylated β‐cyclodextrin. The glass transition temperature of 4 of 124 °C was compared with the lower value of 61 °C of the ring‐opened analogue poly(N‐benzyl‐N‐ethylacrylamide). © 2015 Society of Chemical Industry  相似文献   

17.
以精C9馏分为原料,丙烯酸为接枝单体,选择偶氮二异丁腈和无水乙醇作为引发剂和溶剂,石油醚作为萃取剂,采用自由基溶液聚合法合成了C9-AA石油树脂。采用正交试验法考察了反应中原料配比、溶剂用量、引发剂用量、反应时间等对可聚组分转化率的影响,确定了最佳反应条件。结果表明:引发剂用量为10%,溶剂用量为25%,在65°C下反应5.5 h,当n(C9馏分)∶n(丙烯酸)为1∶2时,可聚组分转化率可达96.74%。红外光谱分析证实了接枝产物的生成。  相似文献   

18.
In this paper, the high value-added (ultra-low degree of polymerization [ULDP]) polyvinyl alcohol (PVA) product was successfully prepared by oxidative chain scission method with sodium hypochlorite as an oxidant. When the molar ratio of PVA to NaClO is not less than 1:1.8, the reaction is stirred for several hours (≥2 h) at a temperature not exceeding 50°C. After precipitation and washing in methanol, PVA with polymerization degree of 38–150 can be obtained after drying. The infrared spectrum (IR) and nuclear magnetic hydrogen spectrum (1H-NMR) test proved that the product obtained by this method is indeed PVA. The results of 1H-NMR also showed that the chain broken has no selectivity and the stereoregularity of hydroxyl group did not change significantly. Through radical quenching experiment and electron paramagnetic resonance (EPR) analysis, it is proved that OCl is the main active oxide, ·Cl makes the oxidative chain scission process can be realized quickly, and ·OH is an indispensable factor for obtaining ULDP PVA. Under the combined action of these three, high value-added PVA with ULDP was successfully prepared. Additionally, the sodium hypochlorite oxidized the ·OH captured by 5,5-dimethyl-1-pyrroline-n-oxide (DMPO-OH) to 2-hydroxy-5,s-dimethyl-1-pyrroline-N-oxide (HDMPO-OH) in an alkaline environment.  相似文献   

19.
An experimental investigation of the kinetics of the bulk free radical copolymerization of styrene/butyl acrylate initiated with 2,2′-azobisisobutyronitrile (AIBN) was conducted at 50°C using various initiator concentrations and initial monomer ratios including the azeotropic composition. Reactivity ratios were determined by analyzing composition data using the error-in-variables model. The experiments, designed using the Tidwell-Mortimer criterion, were conducted in sealed ampoules at 50°C to low conversion levels (< 7%). From the calculated reactivity ratios, the azeotropic composition was determined and further experiments were run at these conditions as well as at two other initial monomer feed compositions in order to collect composition, rate and molecular weight data. The experiments were run through the full conversion range at two different initiator concentrations.  相似文献   

20.
Polyether polyurethane networks were prepared in solution at 25 and 60°C, using various organotin catalysts. The presence of a free‐radical initiator [viz. azobisisobutyronitrile (AIBN)] in the reaction media has no effect on the catalytic efficiency of organotin(IV) compounds, whereas it causes severe deactivation of organotin(II) compounds. This effect was explained by the following mechanism: formation of a cyclic 1 : 1 complex by coordination of the nitrile groups of AIBN with the tin(II) atom, which both reduces the effective catalyst concentration and allows the early decomposition into radicals, as previously seen, leading to tin oxidation. The addition of a free‐radical scavenger such as 3‐tert‐butyl pyrocatechol allows the maintenance of the catalyst efficiency of organotin(II) compounds at their reference level. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1929–1937, 2002  相似文献   

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