天然杜仲橡胶的提取效率研究

本文首先研究了两种预处理方法,即超微粉碎和生物酶解预处理,在提取天然杜仲橡胶方面的异同之处及其对天然杜仲橡胶品质的影响;其次,研究了超声波提取方法中,提取温度、时间、超声频率对天然杜仲橡胶的提取效率的影响。     

杜仲不同部位总黄酮含量的测定

用微波法对杜仲不同部位提取总黄酮,以芦丁作为对照品,用硝酸铝-亚硝酸钠显色、用紫外-可见分光光度计测得杜仲老叶、嫩叶、细枝、粗枝、一年生枝、主杆、主杆皮、主根、主根皮、须根的总黄酮含量分别为 6.05%、4.65%、0.52%、0.33%、0.285%、0.23%、0.15%、0.15%、0.155%、0.165%。结果显示老叶中总黄酮的含量最高,可以对杜仲叶的利用进行更多的探索。     

中国杜仲资源的综合利用

杜仲（Eucommia ulmoides oliv）是我国特有植物,现有资源量大。杜仲长期仅以皮入药,资源利用率低。本文对杜仲雄花,杜仲叶,杜仲果等部位的有效成分进行了详细论述,并就其开发利用提出了建议。     

杜仲叶中总黄酮抗氧化性能研究

对杜仲叶黄酮提取物进行了抗氧化性能研究。结果表明,杜仲叶黄酮提取物具有较好的还原能力,同时对超氧阴离子有较强的清除作用,且随着黄酮添加量的增大活性增强。研究表明,杜仲叶黄酮是一种天然有效的抗氧化剂。     

杜仲胶在橡胶领域的应用及研究进展

对杜仲胶与其他合成橡胶的相容性、生物代谢合成杜仲胶的新发现、杜仲胶结晶表征新方法等进行了总结,并综述了杜仲胶的化学改性方法及应用,杜仲胶在轮胎、功能膜材料及形状记忆材料等领域的应用,提出了杜仲胶未来的发展趋势.     

杜仲叶中总黄酮抗氧化性能研究

对杜仲叶黄酮提取物进行了抗氧化性能研究。结果表明,杜仲叶黄酮提取物具有较好的还原能力,同时对超氧阴离子有较强的清除作用,且随着黄酮添加量的增大活性增强。研究表明,杜仲叶黄酮是一种天然有效的抗氧化剂。     

The geometric isomers of conjugated octadecadienoates from dehydrated methyl ricinoleate

The dehydration of methyl ricinoleate by heatingin vacuo in the presence of KHSO₄ resulted in the formation of the following conjugated octadecadienoates expressed as a percentage of the final product:cis, trans (trans, cis), 14.3;cis, cis, 11.2;trans, trans, 7.3. The isomers contained the double bonds predominantly in the 9,11 position but the possible presence of traces of 8,10 and other conjugated isomers is not excluded. Using urea “inclusion” fractionation and low temp crystallization from acetone methyl,cis-9,cis-11-octadecadienoate was isolated. The methyl esters of commercially dehydrated castor oil fatty acids on the other hand, contained the following percentages of conjugated octadecadienoate isomers:cis, trans (trans, cis), 20.3;cis, cis, 8.0;trans, trans, 5.4. From these mixtures conc ofcis, trans (trans, cis)- andtrans, trans-octadecadienoates were prepared by fractional distillation and low temp crystallization. It was found that the conjugated octadecadienoates consisted of mixtures of positional isomers with double bonds mainly in the 8,10 and 9,11 positions with lesser amounts in the 7,9 and 10,12 positions.     

杜仲皮不同萃取部位抗氧化活性研究

以Vc为阳性对照,对杜仲皮的石油醚、氯仿、乙酸乙酯、正丁醇萃取物清除羟自由基(·OH)及1,1-二苯基-2-苦苯肼自由基(·DPPH)活性进行研究。结果表明,杜仲皮不同溶剂萃取物均有一定的抗氧化活性。     

Analysis of the geometric isomers of methyl linoleate by gas chromatography

The four geometric isomers of methyl linoleate have been quantitatively determined by gas chromatography on Apiezon L and DEGS polyester capillary columns. Three peaks were eluted from the Apiezon L column: (a) the 9-cis, 12-cis isomer; (b) the 9-cis, 12-trans isomer; and (c) the 9-trans, 12-cis and 9-trans, 12-trans isomers combined. The DEGS polyester column also resolved three peaks: (a) the 9-trans, 12-trans isomer; (b) the 9-cis, 12-cis and 9-cis, 12-trans isomers combined; and (c) the 9-trans, 12-cis isomer. Since the separation of isomers was different on each column, the content of each of the four isomers could be determined from the combined results. Quantitative results agreed closely with the per centtrans bonds as determined by infrared analysis. Presented at the fall meeting of the American Oil Chemists' Society, Chicago, Illinois, October 30-November 1, 1961. Supported in part by a grant from Cargill, Ineorporated.     

杜仲胶提取与规模化生产现状及其产业发展面临的问题

杜仲是我国非常宝贵的战略资源,杜仲胶是带动杜仲大产业发展的核心动力.杜仲胶产业的发展不仅能够改善我国天然橡胶不足的现状,还可以为我国提供新的来源充足的后备胶种,形成以我国杜仲胶新兴产业为龙头的国际天然橡胶市场新格局.近年来,杜仲胶产业化和应用开发虽然取得突出进展,但还远不能适应形势发展的需要,究其原因是杜仲产业链的发展...     

响应面优化杜仲总黄酮的沉淀分离工艺

用离子沉淀法分离杜仲叶中总黄酮,在单因素实验基础上,用响应面优化法考察了沉淀剂用量、沉淀温度和沉淀时间对杜仲总黄酮得率的影响。结果表明,50 m L提取液中,添加108 m L澄清石灰水作沉淀剂,60℃下沉淀50 min,总黄酮得率为5.92%。     

The occurrence of methyl methoxystearate isomers in the methyl esters prepared from sheep perinephric fat

A fraction has been isolated from sheep perinephric fat and identified by techniques which included mass and infrared spectrometry, as a mixture of the 8 to 14-methoxyoctadecanoic acid isomers. It is postulated that these isomers are artifacts produced by rigorous esterification with methanol and concentrated H₂SO₄ of a large sample of sheep perinephric fatty acids which are presumed to have contained trace amounts of constituent hydroxy fatty acids. It is estimated that these methoxystearic acid isomers represented approximately 0.08% of the total weight of fatty acids.     

响应面优化杜仲总黄酮的沉淀分离工艺

用离子沉淀法分离杜仲叶中总黄酮,在单因素实验基础上,用响应面优化法考察了沉淀剂用量、沉淀温度和沉淀时间对杜仲总黄酮得率的影响。结果表明,50 m L提取液中,添加108 m L澄清石灰水作沉淀剂,60℃下沉淀50 min,总黄酮得率为5.92%。     

酶法及半仿生法提取杜仲叶中绿原酸和黄酮

为优选杜仲叶中绿原酸和黄酮提取最佳工艺,以绿原酸和黄酮含量为考察指标,通过正交实验对半仿生法和酶法两种提取方法进行了优化。半仿生法的工艺条件为:杜仲叶为原料,以磷酸氢二钠-柠檬酸的缓冲溶液作为提取液,m(杜仲叶)∶m(提取液)=1∶20,提取液pH分别为2.0,7.5,8.3,在70℃,每次提取1 h,提取3次;在此条件下,绿原酸的得率达1.44%,黄酮得率达0.044%。果胶酶提取的工艺条件为:杜仲叶为原料,以磷酸氢二钠-柠檬酸的缓冲溶液作为提取液,m(杜仲叶)∶m(提取液)=1∶15,果胶酶酶解温度为60℃;提取液pH为3.6;每5 g杜仲叶中加入质量分数为0.5%果胶酶1.5 mL,酶解2 h后,升温至80℃,每次1 h,提取3次;在此条件下,绿原酸的得率达1.29%,黄酮得率达0.043%。     

Polymorphism in single-acid triglycerides of positional and geometric isomers of octadecenoic acid

The polymorphism of 25 glycerol trioctadecenoates with double bonds ranging from Δ4-Δ17 was investigated by differential scanning calorimetry. Triglycerides withcis bonds in odd positions Δ7-Δ13 exhibited three intermediate melting (β′-) forms, but those withcis bonds in even positions, exceptcis Δ4, lacked β′-forms. Among thetrans compounds, only Δ11, 13, and 14 showed β′-forms. Thecis andtrans Δ5 triglycerides were unusual, because they readily assumed low melting (α-) forms that were not easily converted to high melting (β-) forms. β-Form mp of compounds in each series (cis ortrans) alternated depending upon double bond position; an even position correlated with high mp. Heats of fusion (ΔH_f) for β-forms, likewise, fluctuated with double bond position but nonuniformly;trans Δ6 had the highest ΔH_f (43 cal/g),cis Δ12 the lowest (21 cal/g).     

不同方式处理杜仲雄花总黄酮的提取及抗氧化性研究

以杜仲雄花为原料,单因素结合正交实验,研究了超声辅助杜仲雄花总黄酮的最佳提取工艺条件,并评价不同处理方式对其总黄酮含量的影响及抗氧化性。结果表明,杜仲雄花总黄酮的最佳提取工艺为:乙醇浓度60%,超声温度60℃,超声功率250 W,超声时间20 min,料液比1∶30(g/m L)。该条件下,阴干、杀青、炒制和花粉样品的提取率分别是2.18%,1.85%,3.58%和2.46%,杜仲雄花总黄酮能够有效地清除羟基自由基、超氧阴离子自由基和亚硝酸盐,优于同浓度条件下抗氧化剂VC。     

不同方式处理杜仲雄花总黄酮的提取及抗氧化性研究

以杜仲雄花为原料,单因素结合正交实验,研究了超声辅助杜仲雄花总黄酮的最佳提取工艺条件,并评价不同处理方式对其总黄酮含量的影响及抗氧化性。结果表明,杜仲雄花总黄酮的最佳提取工艺为:乙醇浓度60%,超声温度60℃,超声功率250 W,超声时间20 min,料液比1∶30(g/m L)。该条件下,阴干、杀青、炒制和花粉样品的提取率分别是2.18%,1.85%,3.58%和2.46%,杜仲雄花总黄酮能够有效地清除羟基自由基、超氧阴离子自由基和亚硝酸盐,优于同浓度条件下抗氧化剂VC。     

张家界不同产地杜仲叶/皮中矿质元素含量的测定及比较

采用火焰原子吸收分光光度法测定了张家界不同产地杜仲叶及皮中Fe、zn、Cu、Mn、Mg、K、Ca等7种矿质元素的含量,结果表明杜仲叶及皮中各种矿质元素含量丰富,各元素含量的高低趋势在杜仲叶中大致为：Mg〉K〉Ca〉Zn〉Fe〉Mn≥Cu,在杜仲皮中大致为：Mg〉Ca〉K〉Fe〉Zn〉Mn≥Cu。K—S检验可以看出杜仲叶及皮中各矿质元素含量均服从正态分布,LSD检验可以得出张家界不同产地杜仲叶中Fe、Mn、Mg及杜仲皮中Fe、Mn、K元素的含量存在差异性显著。这一结果可以为不同产地杜仲叶／皮的药理活性及其品质的差异提供一定的理论依据。     

杜仲中环烯醚萜类化合物的快速制备色谱制备及反相高效液相色谱/核磁共振鉴定

建立了杜仲中环烯醚萜类化合物京尼平甙酸(GPA)和京尼平甙(GPS)的快速制备色谱制备及反相高效液相色谱/核磁共振(RP-HPLC/NMR)鉴定方法。杜仲皮醇提物用硅胶柱层析法纯化后,进行快速制备液相色谱分离,根据制备色谱图收集流出液,采用HPLC-PDA和核磁共振(NMR)法定性定量分析。制备色谱条件为:流动相,V(甲醇)∶V(水)∶V(乙酸)=40∶60∶0.5;流速,2.5 mL/m in;检测波长,254 nm;进样体积,2.5 mL;进样量,100 mg;柱温,室温。结果表明,RP-HPLC分析制得产品的质量分数分别为w(GPA)=94.69%和w(GPS)=93.27%,核磁共振法测定结果与文献报道一致,确定实验所得两种单体为京尼平甙酸和京尼平甙。     

Diet‐dependent occurrence of CLA isomers in rumen and duodenal digesta of slaughtered bulls

This study examined the effects of linolenic acid‐rich vs. linoleic acid‐rich feeding system on the occurrence of individual CLA isomers in the rumen and duodenum digesta of German Holstein and German Simmental bulls using Ag⁺‐HPLC/DAD. The diet affected the biosynthesis of individual CLA isomers in the rumen of the bulls of both breeds. The isomer t‐11,c‐13 CLA was detected as the most abundant isomer in the rumen of linolenic acid‐rich diet‐fed bulls, up to six times higher compared to linoleic acid‐rich diet‐fed bulls. However, the main isomer in muscle lipid, c‐9,t‐11 CLA, was produced to a low extent in the rumen of linolenic acid‐rich diet‐fed bulls compared to higher concentrations of this isomer in the rumen of linoleic acid‐rich diet‐fed bulls. The isomers t‐7,c‐9 CLA and t‐8,c‐10 CLA were not present in the rumen samples of bulls fed both diets; however, abundant t‐7,c‐9 CLA was identified in the duodenum. The CLA isomers t‐12,t‐14 CLA and t‐11,t‐13 CLA were identified as the main t,t CLA isomers in the rumen, and were significantly enhanced in the rumen of linolenic acid‐rich diet‐fed compared to linoleic acid‐rich diet‐fed bulls. In contrast to c‐9,t‐11 CLA, the t,t CLA isomers seem to be biosynthesized predominantly in the rumen, further transported via the duodenum and finally deposited in the tissue lipids mainly in linolenic acid‐rich diet‐fed bulls. This was shown earlier for muscle and subcutaneous fat samples from the same animal experiment.