落叶松树皮原花青素提取工艺的研究

本文考察了落叶松树皮原花青素的料液比、乙醇浓度、提取温度、超声时间对原花青素提取效果的影响。采用正交实验,对提取工艺进行了优化。结果表明各因素对原花青素的提取效果的影响程度为提取温度>提取时间>乙醇浓度>料液比。从而确定落叶松树皮中原花青素的最佳工艺条件为:提取温度为35℃,提取时间为0.5 h,乙醇浓度为50%,料液比为1∶15(g/mL)。     

锈毛莓总黄酮的提取工艺优化

采用乙醇回流提取法,对提取温度、乙醇浓度、时间、料液比进行单因素考察,结合正交试验,确定锈毛莓总黄酮最佳提取工艺。结果显示,最佳提取工艺为料液比1∶25、乙醇浓度60%、提取温度70 ℃、提取时间2.5 h,提取2次,总黄酮得率可达6.78%。     

野西瓜低聚糖的提取及含量测定

目的:确定野西瓜低聚糖提取工艺参数并测定其含量.方法:对提取温度、提取时间、料液比和乙醇浓度进行了单因素和L9(34)正交试验;用分光光度法测定了野西瓜中低聚糖含量.结果:影响野西瓜低聚糖提取率的4个因素的影响程度依次为:提取时间>提取温度>乙醇浓度>料液比.最佳提取条件为:提取温度70℃、提取时间70min、料液比1/25、乙醇浓度80%,在此实验条件下低聚糖得率为3.70%.结论:实验结果为野西瓜低聚糖的进一步研究提供科学依据.     

枇杷叶中黄酮类化合物提取工艺研究

以枇杷叶为原料,对黄酮类化合物的提取工艺进行研究,考察乙醇浓度、提取温度、提取时间、料液比对枇杷叶中黄酮类化合物提取率的影响,并采用正交实验进行优化。结果表明四种因素对枇杷叶中黄酮类化合物提取率影响的大小顺序为:乙醇浓度>提取时间>提取温度>料液比,枇杷叶中黄酮类化合物提取的最佳工艺条件为提取时间30min、提取温度80℃、乙醇浓度40%、料液比1:20(g/mL),最佳条件下黄酮类化合物提取率为6.92%。     

正交实验优选月腺大戟根总黄酮的提取工艺

目的：研究月腺大戟根中总黄酮类化合物的提取工艺,为研发新型植物源农药提供理论基础。方法：采用索氏提取法对月腺大戟根总黄酮进行提取,以乙醇体积分数、提取时间、提取温度、料液比为实验因素,以提取的总黄酮含量为指标,对提取工艺进行考察,确定最佳提取条件。结果和结论：根总黄酮提取的优化条件为：提取时间2h,提取温度70℃,料液比1：40,乙醇浓度50％;影响提取的主次顺序为：料液比〉提取时间〉乙醇浓度〉提取温度;其中料液比和提取时间是影响根总黄酮提取效果的显著因素。     

超声波辅助大米草总黄酮提取及抗氧化活性研究

应用超声波技术,以大米草为原料提取黄酮类化合物,设计正交实验,研究乙醇浓度、料液比、超声处理温度和提取时间对总黄酮提取效果的影响,分析得出最佳提取工艺条件。并测定大米草黄酮体外抗氧化活性。结果表明:大米草总黄酮提取的最佳工艺条件为:乙醇浓度80%,提取时间20 min,料液比1∶30(g·mL-1),提取温度45℃。影响大米草黄酮提取率的主次因素是:料液比乙醇浓度提取温度提取时间。大米草黄酮总抗氧化活性和抗超氧阴离子活力随着浓度的增加逐渐增加,呈明显的量效关系,并且能有效清除氧化脂质(MDA)。     

陇蜀杜鹃叶中金丝桃苷提取工艺研究

通过单因素和正交实验,提取陇蜀杜鹃叶中主要活性成分金丝桃苷,采用高效液相色谱法测定,确定金丝桃苷的最佳提取工艺。结果显示影响陇蜀杜鹃叶中金丝桃苷得率的主要因素是乙醇浓度,各因素影响顺序为乙醇浓度料液比提取温度提取时间,金丝桃苷最佳提取工艺为:乙醇浓度50%、料液比1∶25、提取温度80℃、提取时间1 h,得率为0.68%。该方法提取陇蜀杜鹃叶中的金丝桃苷得率高,稳定性好,工艺可控性强。     

壮药山风总黄酮提取工艺的优化研究

采用正交试验对超声辅助提取壮药山风中总黄酮的工艺进行优化,通过考察黄酮的提取温度、乙醇浓度、料液比、提取时间,得到山风总黄酮的最优提取条件为:提取温度80℃、乙醇浓度60%、料液比1∶40 g·mL-1、提取时间20 min,提取率为24.72 mg·g-1,为进一步开发壮药山风的药用及功能性食品利用价值提供理论参考。     

莲子心总黄酮的超声波萃取工艺研究

研究了超声波萃取法从莲子心中提取总黄酮的最佳工艺。通过单因素控制法和正交试验,以乙醇为溶剂,总黄酮提取率为考察指标,在超声波辅助下研究了乙醇浓度、提取时间、料液比和提取温度对总黄酮提取率的影响。结果表明影响莲子心中总黄酮提取率的主要因素是乙醇的浓度,其次依次为提取温度、料液比、超声波萃取时间;提取的最佳条件是:乙醇的浓度为60%,提取温度是70℃,料液比为1:24,超声波萃取时间为30 min,此条件下得到的总黄酮的提取率是10.86 mg/g。     

少花龙葵茎总黄酮提取工艺及其抗氧化性研究

采用乙醇浸提法对Solanum photeinocar pum茎总黄酮的提取工艺及其抗氧化性能进行了研究,探讨了溶剂浓度、温度、提取时间、料液比等因素对总黄酮含量提取的影响,并采用正交实验对提取工艺进行优化。结果表明,最佳提取工艺参数乙醇浓度为40%,提取温度为80℃,时间为1h,料液比1:16(g:mL)。在此条件下测得总黄酮含量为4.39mg/g,提取物对羟自由基具有较好的清除效果。     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen derAlismataceae,Liliaceae, Juncaceae,Cyperaceae, Poaceae undAraceae

Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout.

     

Identification and Characterization of the First Equine Parainfluenza Virus 5

正Dear Editor,Parainfluenza virus 5 (PIV5), known as canine parainfluenza virus in the veterinary field, is a negative-sense,nonsegmented, single-stranded RNA virus belonging to the Paramyxoviridae family (Chen 2018). The virus was first reported in primary monkey kidney cells in 1954 (Hsiung1972), then it has been frequently discovered in various