响应面分析法优化乙酸乙酯萃取番茄红素条件的研究

采用响应面方法对番茄酱提取番茄红素过程中的乙醇预处理方法、萃取剂萃取时间等工艺条件进行了优化。采用Central Composite Design(CCD)设计法,对超声波提取法和微波提取法中的乙醇预处理、萃取剂萃取时间、超声波或微波萃取功率、溶剂量4个因素对番茄红素提取率的影响进行评价。结果显示,最佳提取方法为超声波提取法,无水乙醇∶番茄酱的2.05∶1(V/W);乙酸乙酯∶番茄酱10.1∶1(V/W);提取时间为490 s;超声波提取功率为405 W;提取率为94.42%。微波提取最佳方法为,无水乙醇∶番茄酱的2.11∶1(V/W);乙酸乙酯∶番茄酱10.1∶1(V/W);提取时间为372.6 s;微波提取功率为569.5 W;提取率为81.51%。     

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。     

樟芝挥发油的微波辅助双液相萃取及其抗菌活性研究

采用微波辅助石油醚/乙醇双液相萃取技术提取樟芝发酵液中的挥发油,并考察了其对7种皮肤癣菌的最低抑制浓度(MIC)。优化的提取条件为:乙醇体积浓度56%,石油醚体积浓度30%,固液比1∶50,微波功率380 W,微波时间90 s。此时,挥发油的提取率为0.69%,真菌MIC为5-20 m L/L。微波辅助双液相萃取挥发油耗时短,提取率高,且获得的挥发油抗皮肤癣菌效果显著。     

樟芝挥发油的微波辅助双液相萃取及其抗菌活性研究北大核心CSCD

采用微波辅助石油醚/乙醇双液相萃取技术提取樟芝发酵液中的挥发油,并考察了其对7种皮肤癣菌的最低抑制浓度(MIC)。优化的提取条件为:乙醇体积浓度56%,石油醚体积浓度30%,固液比1∶50,微波功率380 W,微波时间90 s。此时,挥发油的提取率为0.69%,真菌MIC为5-20 m L/L。微波辅助双液相萃取挥发油耗时短,提取率高,且获得的挥发油抗皮肤癣菌效果显著。     

超声微波协同萃取(UMAE)番茄中番茄红素的研究

研究了超声微波协同萃取番茄中的番茄红素。以乙酸乙酯为萃取溶剂并以不同的提取时间、微波功率和液固比作为参数进行实验,并进行了工艺优化。在提取时间367s、微波功率98W和液固比10．6：1的条件下实际提取率可达到97．4％。实验结果表明：UMAE法是一种能够快速有效的提取番茄红素的方法。     

微波辅助提取补阳还五汤多糖的研究

采用单因素实验和正交实验法,进行了微波辐射萃取补阳还五汤多糖的最佳工艺条件研究。探讨了不同微波辐射时间、微波功率及料液比等条件对多糖提取率的影响。结果表明,在微波辐射时间20min,微波功率325W,料液比为1：7,补阳还五汤中多糖的提取率为7．75％。微波辅助萃取大大缩短了提取时间,节省了溶剂,提高了收率。     

密闭微波辅助间歇提取RP-HPLC测定三七中三种皂苷类化合物

本文建立了采用微波辅助间歇提取三七样品中的皂苷类化合物,并以反相高效液相色谱（RP—HPLC）测定其中三七皂苷R1、人参皂苷Rg1和人参皂苷Rb1含量的实验方法。分别通过单因素实验和正交实验设计,优化了萃取溶剂浓度、溶剂用量、微波功率和微波辐射时间等提取条件。与传统的索氏提取法、冷浸法和超声波提取法比较,微波辅助萃取法具有快速、提取率高、溶剂消耗少等优点,间歇萃取较连续萃取更是大大节省了微波能耗。     

利用微波辅助萃取技术提取五味子果实中五味子醇甲的研究

采用乙醇和水作为萃取剂,研究了用微波辅助萃取的方法从五味子果实中萃取五味子醇甲。以不同的萃取时间、萃取功率、萃取溶剂/基质比作为参数进行实验,利用高效液相色谱(HPLC)作为五味子醇甲的检测手段。实验结果表明:在萃取产率上,乙醇的萃取效果优于水(乙醇的萃取产率0.72%,水的萃取产率0.47%),但是在萃取选择性方面,水作为萃取剂优于乙醇。以乙醇和水作为溶剂的最优微波辅助萃取条件是:温度接近溶剂的沸点(乙醇设为72℃,水设为95℃),微波功率350 w,萃取时间5~8 min,萃取液固比12:1。萃取时间的延长和微波功率的增加都会导致五味子醇甲的萃取产率下降。     

微波辅助法从黎蒿中提取黄酮类化合物的研究

本文介绍了一种有效利用微波辅助从藜蒿(Artemisia selengnesisTurcz)中提取黄酮类化合物的方法。通过考察了微波辐射时间、功率、料液比及提取溶剂等因素对提取率的影响,得出的结论为:以75%乙醇做提取溶剂,密封条件下,功率200 W,料液比1 g∶25 mL,辐射时间20 s/次×3次,提取率最高。与传统提取方法相比,该方法不仅工艺简单,而且可以提高产率,缩短提取时间。     

响应面法优化微波辅助提取山苍子核仁油的研究

通过微波辅助提取技术结合响应面法优化山苍子核仁油提取条件,以期建立更高产率的提取方法。该研究在单因素设计基础上,选取液料比、微波功率、萃取时间、萃取温度4个主要因素,分析这4个因素对山苍子核仁油提取率的影响。结果表明:通过建立多元回归拟合分析,得出山苍子核仁油提取最佳工艺条件为液料比1∶16,萃取温度为69℃,微波功率为337 W,萃取时间为63 min,在此条件下山苍子核仁油提取率为37.42%,与环己烷溶剂回流法相比较提取率提高了30.11%。气质联用仪分析结果显示,山苍子核仁油主要成分有16种占总成分的88.21%,鉴定出10种脂肪酸占总成分的78.24%,饱和脂肪酸有4种占总成分的43.23%,不饱和脂肪酸有6种占总成分的35.01%,脂肪酸中含量最高的为月桂酸(31.36%)。该研究结果表明该方法严谨、可靠,采用微波辅助提取山苍子核仁油是可行的。     

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