淫羊藿属木脂素类化学成分研究进展

目的是对淫羊藿属木脂素类成分研究进展进行综述,为其进一步开发研究提供参考;方法是对国内外相关文献进行分析、整理和归纳;结果是综述了近40种木脂素类成分,其中有10余种属于自然界首次发现的新化合物,文中均给出其英文名称、文献来源等内容;结论是以往淫羊藿木脂素类成分的报道相对较少,其化学成分和药理活性亟待进一步研究。     

五味子科植物木脂素成分的化学

木脂素是五味子科植物中的主要生物活性成分 ,具有抗肝炎、抗癌、抗爱滋病毒、PAF拮抗及保护中枢神经系统等作用。为了确定木脂素的结构及寻求活性更高的成分 ,对五味子科植物木脂素成分的化学反应作了总结     

内消旋二芳基丁烷类木脂素的合成研究

以简单的芳香醛为起始原料,经Knoevenagel反应、还原成酮、频哪醇偶联和消除反应得到重要中间体二芳基丁烯类化合物;分步结晶分离出顺式二芳基丁烯类化合物,将其催化氢化得到终产品内消旋二芳基丁烷类木脂素。其结构经1H-NMR和MS确认。本方法不仅路线短、反应条件温和、收率较高,而且关键中间体顺式二芳基丁烯类化合物易于分离得到,具有很高的立体异构纯度。     

五味子藤总木脂素抗氧化活性研究

目的：通过体外抗氧化测试,评价五味子藤总木脂素固形物的抗氧化活性。方法：采用分光光度法检测五味子藤总木脂素固形物的总抗氧化能力（T-AOC）及对超氧阴离子自由基的清除能力。结果：五味子藤总木脂素固形物的总抗氧化值及对超氧阴离子自由基的抑制率均呈现浓度依赖性;当浓度为0.2 mg/mL时,总抗氧化值为（8.89±0.34） U/mg,约为同浓度VC的1/5,对超氧阴离子自由基的抑制率为（26.932±1.031）%,约为同浓度VC的1/4。结论：五味子藤总木脂素固形物具有一定的抗氧化活性。     

五味子中总木脂素的提取工艺优化研究

用乙醇提取五味子中总木脂素,考察了乙醇浓度、料液比、超声时间和提取温度对总木脂素提取率的影响。结果表明,五味子中总木脂素最佳提取工艺条件为:采用70%的乙醇作为提取溶剂,以1∶14(g/mL)的料液比冷浸12 h后,超声提取30 min,提取温度为50℃。五味子中总木脂素提取工艺简便、合理,为总木脂素的分离纯化、含量测定及生理活性的开发研究奠定了基础。     

索氏法提取五味子中木脂素

采用索氏提取法提取水浸预处理后的五味子中的木脂素,考察了虹吸次数、液固比、颗粒粒径及乙醇浓度对萃取率的影响,采用响应面法进行优化. 结果表明,五味子醇甲的最佳提取条件为：乙醇浓度98.05%(j),液固比67.20 mL/g,颗粒平均粒度0.33 mm,该条件下理论萃取率为80.90%,实际萃取率为77.17%;五味子甲素的最佳提取条件为：乙醇浓度96.38%(j),液固比72.52 mL/g,颗粒平均粒度0.21 mm,该条件下五味子甲素理论萃取率为77.11%,实际萃取率为74.31%;五味子乙素的提取最佳条件为：乙醇浓度96.38%(j),液固比72.52 mL/g,颗粒平均粒度0.21 mm,该条件下理论萃取率为77.13%,实际萃取率为74.23%. 各因素对木脂素提取率影响的显著性顺序为乙醇浓度>液固比>颗粒粒径.     

碳酸钾催化合成芳基萘内酯类木脂素

以二氯乙烷作溶剂,炔酸烯丙酯在K2CO3催化下,可以顺利发生分子内串联环化反应得标题化合物,产率65％ ～88％.产物经1HNMR、13CNMR和GC-MS确证.     

芳基二氢萘类木脂素的不对称合成研究进展

天然木脂素是由含酚羟基的苯丙素类化合物在生物酶催化下,通过氧化偶联反应而形成的。因此,以氧化偶联反应为关键步骤来仿生合成各类木脂素是最常用也是最快捷的合成途径。文章将就如何利用氧化偶联反应,在生物体外进行简单快捷的构建芳基萘类木脂素的基本骨架结构展开相关论述。     

木脂素的生物合成及其微生物法生产的研究进展

木脂素是一类分布于植物中的次级代谢产物,由两分子苯丙素衍生物聚合而成。木脂素具有抗细菌、抗病毒和抗真菌活性,被广泛用于药物和食品中。目前,木脂素的生产主要依赖于植物提取。植物生长周期长、木脂素含量低等问题,限制了木脂素的商业应用。随着木脂素合成路径和关键酶的不断解析,木脂素的生物催化合成过程受到了越来越多的关注。本文总结了典型木脂素的生物活性、生物合成路径和微生物法生产的研究进展,可以为深入研究木脂素的微生物合成提供参考。     

溶剂萃取五味子粗提液中的木脂素

以水蒸气蒸馏提油、超声醇提、减压浓缩后得到的五味子木脂素粗提液为原料,用溶剂萃取法对五味子木脂素进行提取.选择了合适的萃取溶剂,探讨了石油醚萃取五味子木脂素机理.结果表明,此萃取过程为分子萃取,过程动力学为扩散控制.考察了相比、萃取温度、时间、搅拌速度及萃取级数对五味子木脂素萃取率的影响.在单因素实验的基础上选择萃取温...     

一种从富含多酚多糖的西葫芦组织中快速提取RNA的方法

对比研究了一步法、尿素／氯化锂法、热酚法、LUG法等4种方法,建立了一种适合西葫芦组织RNA提取的改进的CTAB方法。用该方法从西葫芦叶中提取的RNA在琼脂糖凝胶电泳上清楚显示出28S和18S两条链．A250／280值为2.08、A250/280值为2．0,表明提取的RNA没有多酚、多糖、蛋白质污染;RNA产量为210μg·g^-1鲜质量;对RT—PCR的结果进行测序,通过NCBI—BLAST比对可知,与印度南瓜的同源性达89％。用该方法从西葫芦果肉中也获取了高质量的RNA。改进的CTAB法全程只需2h,不用液氮、亚精胺、二硫苏糖醇、蛋白酶K等试剂。     

Seeds and oil of the Styrian oil pumpkin: Components and biological activities

Cucurbita pepo subsp. pepo var. Styriaca is a phylogenetically young member of the Cucurbita spp. since the mutation leading to dark green seeds with stunted outer hulls arose only in the 19^th century. This mutation defined the so‐called Styrian oil pumpkin and facilitated the production of Styrian pumpkin seed oil. It is a regional specialty oil in the south‐eastern part of Europe. In this article, we describe the production and economic value of this edible oil as well as its composition on a molecular basis, including fatty acids, vitamins, phytosterols, minerals, polyphenols, and the compounds responsible for its pigments, taste and flavor. We also describe contaminants of Styrian pumpkin seed oil and the most relevant field pests of the Styrian oil pumpkin plant. Finally, we review the putative beneficial health effects of Styrian oil pumpkin seeds and of their products.     

Biologically Active Digests from Pumpkin Oil Cake Protein: Effect of Cross-linking by Transglutaminase

The objective of this study was to show that biologically active hydrolysates can be obtained by simulated human gastrointestinal digestion (HGD) of transglutaminase cross-linked pumpkin oil cake protein (Tg-C) which was previously reported as a potential functional food additive. A two-stage in vitro digestion model system (by pepsin and α chymotrypsin and trypsin, simultaneously) was used to simulate the process of HGD on native and Tg-C major storage pumpkin oil seed/cake protein, cucurbitin (C). The biologically active potential of the digests was evaluated, measuring the angiotensin-converting-I enzyme (ACE) inhibitory and anti-oxidant capacity. The ACE inhibitory activity was determined in both final digests, with IC₅₀ = 0.30 ± 0.04 mg/ml for C and IC₅₀ = 0.28 ± 0.01 for Tg-C. The anti-oxidant potency of the examined proteins was enhanced by the digestion process. The 2,2-diphenyl-1-picrylhydrazyl and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical cation activities and reducing power testing showed that all the hydrolysates act as a radical quencher and reducing agents. Overall, the results showed that the cross-linking by Tg did not influence the digestion process, as well as having no effect on the biological activity of the hydrolysates. These also indicate that Tg-C, if used as functional food additive, after food consumption can be digested and become a source of peptides exerting positive effects on human health.     

Genome-Wide Identification and Characterization of Members of the ACS Gene Family in Cucurbita maxima and Their Transcriptional Responses to the Specific Treatments

Ethylene biosynthesis and signal transduction play critical roles in plant sex differentiation. ACS (1-aminocyclopropane-1-carboxylic acid synthase) is a rate-limiting enzyme in ethylene biosynthesis. However, the understanding of the ACS gene family in Cucurbita maxima is limited. Here, we identified and characterized 13 ACS genes in the C. maxima genome. All ACS genes could be divided into three groups according to a conserved serine residue at the C-terminus. Thirteen CmaACS genes were found to be randomly distributed on 10 of the 20 chromosomes of C. maxima. The ACS gene exhibits different tissue-specific expression patterns in pumpkin, and four ACS genes (CmaACS1, CmaACS4, CmaACS7, and CmaACS9) were expressed specifically in both the female and male flowers of C. maxima. In addition, the expression levels of CmaACS4 and CmaACS7 were upregulated after ethephon and IAA treatments, which ultimately increased the number of female flowers, decreased the position of the first female flower and decreased the number of bisexual flowers per plant. These results provide relevant information for determining the function of the ACS genes in C. maxima, especially for regulating the function of ethylene in sex determination.     

毛竹纳米纤丝化纤维素/TiO2气凝胶的制备及表征

以钛酸四丁酯为原料,纳米纤丝化纤维素(NFC)为模板,制备NFC/TiO₂气凝胶。采用扫描电子显微镜(SEM)、X射线衍射(XRD)、傅里叶变换红外光谱(FT-IR)、比表面积及孔径分析仪对其进行表征。结果表明:NFC/TiO₂气凝胶中NFC保留了其原有的空间网络结构;TiO₂主要以颗粒的形式附着在NFC表面;通过BET分析可知其比表面积为12.55 m²/g,平均孔径为17.07 nm。     

云南产五味子科药用植物化学成分研究进展

五味子科药用植物中的主要生物活性成分为木脂素、羊毛甾烯型三萜酸及内酯 ,具有抗肝炎、抗癌、抗爱滋病毒、PAF拮抗及保护中枢神经系统等多方面的药理作用。为促进进一步的研究与开发利用 ,本文结合自己的工作 ,对云南产五味子科药用植物化学成分研究进展进行了综述。     

Cucurbitacins fromCucurbita texana: Evidence for the role of isocucurbitacins

In addition to cucurbitacins E andI, cucurbitacins D,1, 3-epi-isocucurbitacin D,2, and B,3, were isolated from the fruits ofCucurbita texana and structurally identified by UV, IR,¹H NMR,¹³C NMR, and MS, and 2-O--glucopyranosylcucurbitacin I was identified. These compounds have not been reported previously as constituents of this species. The isolation of 3-epi-isocucurbitacin D2 together with normal cucurbitacins suggests that isocucurbitacins occur naturally. Evidence is also discussed that isocucurbitacins are biosynthesized one step ahead of normal cucurbitacin.     

超临界流体CO2萃取南瓜籽油的初步研究

以超临界流体CO2萃取技术对南瓜籽中的油脂提取进行了初步研究.研究了不同物料粒度、萃取压力、萃取温度、萃取时间及CO2流量对南瓜籽油萃取率的影响.