超临界CO_2和微波辅助萃取艾叶挥发油工艺的研究

通过超临界CO2萃取均匀设计实验和微波辅助萃取艾叶挥发油的正交实验比较,考察影响提取的主要因素,寻求最佳萃取工艺。超临界CO2萃取最佳工艺条件为:萃取压力16MP,萃取温度31℃,CO2流量20kg/h和时间80min,得率3.75%;微波萃取最佳工艺条件为:辐射功率720w,辐射时间200s,溶剂量400mL,洗涤剂量50mL,得率4.85%。水蒸馏法提取率为1.87%。结果表明超临界CO2和水蒸馏法萃取艾叶挥发油品质最好;微波萃取收率最高,但品质较差。     

白果油的提取工艺及其化学成分研究

采用正交实验对超临界CO2萃取白果油的工艺条件进行优化,比较超声波提取、索氏提取、超临界CO2萃取3种方式对白果油提取率的大小,用最佳提取方式分析不同品种白果中油脂的含量,并用GC-MS分析其成分.结果表明: (1)3种提取方式对白果油提取率的大小顺序为:超临界CO2萃取(添加夹带剂)＞索氏提取＞超声波提取.(2)超临界CO2萃取白果油的最佳工艺条件为:温度40℃、压力20 MPa、流速15 L/h、时间3 h并添加石油醚夹带剂,不同品种白果干粉中油脂得率为3.6%～7.11%.(3)GC-MS分析表明:从超临界萃取白果油中鉴定出17种化学成分,其中不饱和脂肪酸占85.4%;超声波和索氏提取相似,分别从提取的白果油中鉴定出10种和9种化学成分,其中不饱和脂肪酸含量分别为90.3%和90.1%;不饱和脂肪酸以十六、十八碳的为主.     

超临界CO2萃取百合花挥发油的工艺研究

本文介绍了超临界CO2萃取百合花中挥发油的提取分离工艺,重点研究了超临界CO2萃取压力、温度、时间对出油率的影响。正交试验结果表明：影响超临界CO2萃取的主要因素为C3〉A2〉B2（A为萃取压力,B为萃取温度,C为萃取时间）;最佳工艺参数：SC-CO2萃取压力为18MPa,温度为50℃,时间为90min,流量为25L／min,所得百合花挥发油的出油率高达2．92％。     

超临界CO2萃取洋葱挥发油工艺研究

本实验采用超临界CO2萃取技术从冻干洋葱粉中萃取挥发油。以洋葱挥发油得率为考察指标,经单因素及正交试验,考察了萃取温度、萃取压力、CO2流量、萃取时间4个因素对超临界CO2流体萃取的影响。结果表明萃取压力20 MPa,萃取温度35℃,CO2流量为14 kg/h的条件下萃取2.5 h为最佳工艺,洋葱挥发油得率达0.53%。     

超临界CO2萃取石香薷挥发油工艺的研究

石香薷（Molsa chinensis）为多年生草本植物,具有重要的药用价值。本文首次探讨了超临界CO2萃取的压力,温度,流量,时间等条件对石薷挥发油收率的影响,确定其最佳萃取条件,萃取压力15MPa,温度45℃,CO2流量25kg/h和90min,得率为3.56%,水蒸气蒸馏提取得率为1.62%,石油醚提取得率为1.87%,结果表明超临界CO2萃取挥发油比后二者质优,收率大大提高,萃取时间短,无溶剂残留。     

生姜的超临界CO2提取分离工艺的研究

本文研究了超临界CO2流体萃取生姜的工艺,探讨了萃取压力、温度扣时问等因素对生姜萃取率的影响,通过正交实验确定了生姜超临界CO2流体萃取最佳工艺：生姜原料切成薄片,含水率15％以下,萃取条件为压力24Mpa、温度40℃、时间2h。     

超临界CO2萃取鱼腥草的挥发油成分

从萃取的压力、温度、流量和时间等条件探讨超临界CO2萃取对鱼腥草(Houttuynia cordata Thunb.)挥发油萃取率的影响,确定最佳萃取条件为萃取压力20mPa、温度35℃、CO2流量40kg/h和萃取时间80min,鱼腥草挥发油得率为1．76％。而水蒸气蒸馏提取和石油醚提取的得率分别为0．05％和0．08％。超临界CO2法萃取的鱼腥草挥发油收率高,萃取时间短。     

干姜超临界CO2萃取与水蒸气蒸馏工艺比较研究

目的：比较干姜的超临界CO2萃取与水蒸气蒸馏两种工艺的差别,为其在复方制剂中的应用提供工艺设计参考。方法：分别用超临界CO2萃取和水蒸气蒸馏处理干姜药材,采用GC、TLC对产物进行分析比较。结果：超临界CO2萃取产物得率为8．0％,水蒸气蒸馏得率为0．2％,GC、TLC显示超临界CO2萃取物比水蒸气蒸馏样品有较多的成分。结论：干姜的超临界CO2萃取工艺较水蒸汽蒸馏工艺的产物量高,成分较多。     

用GC-MS分析不同方法提取的茶油脂肪酸

用超临界CO2、超声波、微波和机榨4种方法提取茶油,利用GC-MS分析茶油成分。结果表明：超临界CO2萃取的茶油与超声波和微波提取的主要化学成分几乎无差异,机榨茶油的化学成分与前3种的有一些差异,未测出维生素E和角鲨烯。超临界CO2萃取的茶油已达到国家成品茶油的一级标准,超临界CO2萃取法为提取茶油的较理想方法。     

微孔草籽油的超临界CO2流体萃取及HPLC—MS分析

利用超临界CO2萃取微孔草籽油,并对籽油进行了HPLC／MS分析。实验确定的最佳超临界CO2流体萃取条件是：萃取温度45℃,萃取压力20MPa,CO2流量为35-40kg／h,萃取时间120min,在此条件下白刺籽油的萃取率为16．12％。利用HPLC／MS对微孔草籽油分析,发现其不饱和脂肪酸的相对含量高达73．19％。比较了超临界CO2萃取微孔草籽油油样和石油醚萃取微孔草籽油油样的理化性质,发现超临界CO2流体萃取的籽油质量优于传统溶剂萃取的籽油。     

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     

Pathogenic Characterization and Full Length Genome Sequence of a Reassortant Infectious Bursal Disease Virus Newly Isolated in Pakistan

<正>Dear Editor,Infectious bursal disease (IBD) is one of the most important diseases of the poultry. The IBD virus (IBDV), a nonenveloped virus belonging to the Birnaviridae family with a genome consisting of two segments of double-stranded RNA (segments A and B), targets B lymphocytes of bursa of Fabricious leading to immunosuppression. In Pakistan,poultry farming is the second biggest industry and IBD is the second biggest disease threating the poultry sector.However, there is limited genome information of IBDV