土茯苓中提取总黄酮的工艺研究

采用乙醇溶液提取土茯苓饮片中总黄酮,分析了乙醇浓度、温度、固液比、浸取时间对总黄酮提取率的影响。进行了单因素实验设计,得出优化实验条件：乙醇浓度50%,浸取温度80℃,固液比1:20,浸取时间3h,总黄酮提取率为75.8%。     

微波提取山楂中黄酮类化合物的工艺优化

以总黄酮得率为指标,采用微波法辅助提取山楂叶中的总黄酮,选取浸提时间、乙醇体积分数、微波辐射时间、液固比等参数进行单因素试验,选择影响较大的因素,利用Design-Expert 8.0.5b进行响应面分析,得到优化的提取工艺条件:乙醇体积分数56%,液固比51 m L/g,微波辐射时间3.7 min,在此条件下,山楂叶中总黄酮得率为8.923%。     

响应面法优化合萌总黄酮提取工艺

目的:利用响应面法优化合萌中总黄酮的提取工艺条件。方法:通过单因素试验分别考察提取时间、乙醇体积分数、液固比、提取温度及提取次数对合萌总黄酮得率的影响,并选取提取时间、乙醇体积分数、液固比、提取温度为影响因子,应用响应面法优化提取工艺。结果:合萌总黄酮的最佳提取条件为:提取时间60 min,乙醇浓度65%,液固比(g∶m L)25∶1,提取温度90℃,在此条件下,合萌总黄酮得率为4.08 mg/g,接近模型预测值4.11 mg/g。结论:响应面法在一定程度上可以提高合萌总黄酮得率,表明响应面法用于合萌总黄酮提取工艺的优化具有可行性。     

响应面法优化细果角茴香中总黄酮的超声提取条件

采用响应面法优化超声波辅助提取细果角茴香中总黄酮的工艺研究。在单因素试验的基础上,选择超声时间、乙醇浓度、料液比为自变量,以总黄酮的提取率为响应值,进行Box-Behnken中心组合实验设计,采用响应面法(RSM)评估了这些因素对总黄酮提取率的影响。结果表明:超声波法辅助提取细果角茴香中总黄酮的最佳工艺条件为液料比33 mL/g,乙醇浓度为58%,提取时间为34.5 min。在此条件下,总黄酮的提取率达1.525%。     

余甘子总黄酮超声波辅助提取工艺的优化

以余甘子干粉为材料,利用超声波辅助提取余甘子总黄酮。单因素试验分析液料比、乙醇浓度、超声时间、超声功率对余甘子总黄酮提取率的影响,在此基础上,利用响应面分析法对提取工艺进行优化。结果表明,余甘子总黄酮最佳提取条件为：液料比82:1(V/W)、乙醇浓度45%、超声时间41 min、超声功率210 W,在此条件下余甘子总黄酮的实际提取率为6.12%。     

均质剪切辅助响应面法提取扛板归总黄酮及其抗氧化性能研究

为了研究扛板归中总黄酮的最佳提取工艺及其体外抗氧化活性,在高剪切及回流提取单因素的基础上,采用响应面法考察了回流温度、回流时间、料液比、乙醇浓度对提取率的影响。结果显示,扛板归总黄酮最优提取工艺为:回流温度79.86℃,回流时间2.03 h,乙醇浓度51.64%,料液比1∶59(m∶V),剪切次数7次,剪切温度50℃。最优工艺下总黄酮的提取率为8.37%。提取的总黄酮抗氧化性能良好,浓度为8 mg/mL时,对DPPH·、O■和·OH三种自由基的清除率在68%～90%之间。     

响应面法优化蕤核叶片总黄酮提取工艺

采用超声波辅助提取的方法从蕤核叶片中提取总黄酮.利用响应面法(RSM法)研究了超声提取时间、乙醇浓度、液固比、提取温度等因素对总黄酮得率的影响,确定了超声波辅助提取蕤核叶片总黄酮的最佳工艺参数.结果表明,超声波辅助提取蕤核叶片总黄酮的最佳工艺务件为:超声时间50.1 min,乙醇浓度59.5%,液料比24.9:1,提取...     

响应面法优化益母草总黄酮的提取工艺研究

采用响应面法优化超声提取益母草总黄酮的工艺条件。方法:在超声时间、超声功率、超声温度、料液比等单因素的基础上,通过中心组合设计原理采用三因子三水平的响应面分析法设计,对单因子显著性和交互作用进行分析。结果:超声提取益母草总黄酮的最佳工艺条件为:超声时间35.54 min,料液比1∶30.63,乙醇浓度73.41%。此时吸光度为0.295 9。在此条件下益母草的总黄酮提取率为1.21%。结论:优化的提取工艺条件,益母草的总黄酮提取率高,节约资源。     

响应面法优化提取宽叶独行菜总黄酮工艺研究

研究了乙醇浓度、提取温度、提取时间、液料比对超声辅助提取宽叶独行菜总黄酮提取率的影响。采用Box-Bohnken试验响应面分析法优化提取工艺。结果表明最佳提取条件:乙醇浓度75%,提取时间89 min,液料比22.5 mL/g,提取温度79℃,所得的总黄酮提取量为36.5 mg/g。本试验为更好的开发利用宽叶独行菜资源提供一定科学依据。     

响应面法优化微波法提取荷叶中总黄酮的研究

采用微波提取法对荷叶总黄酮进行提取,通过响应面试验分析确定最佳的荷叶总黄酮的最佳提取工艺:微波功率346.57W,微波时间1.04min,料液比1:28.21,乙醇浓度69.65%,理论提取率为5.02%。经3次平行试验的实际平均提取率为4.98%。     

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     

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.     

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.     

Enterovirus 71 3C proteolytically processes the histone H3 N-terminal tail during infection

Highlights
1. The N-terminal tail of histone H3 is specifically cleaved during EV71 infection.
2. Viral protease 3C is identified as a protease responsible for proteolytically processing the N-terminal H3 tail.
3. Our finding reveals a new epigenetic regulatory mechanism for Enterovirus 71 in virus-host interactions.     

Detection of EBV and HHV6 in the Brain Tissue of Patients with Rasmussen’s Encephalitis

Rasmussen’s encephalitis (RE) is a rare pediatric neurological disorder, and the exact etiology is not clear. Viral infection may be involved in the pathogenesis of RE, but conflicting results have reported. In this study, we evaluated the expression of both Epstein-Barr virus (EBV) and human herpes virus (HHV) 6 antigens in brain sections from 30 patients with RE and 16 control individuals by immunohistochemistry. In the RE group, EBV and HHV6 antigens were detected in 56.7% (17/30) and 50% (15/30) of individuals, respectively. In contrast, no detectable EBV and HHV6 antigen expression was found in brain tissues of the control group. The co-expression of EBV and HHV6 was detected in 20.0% (6/30) of individuals. In particular, a 4-year-old boy had a typical clinical course, including a medical history of viral encephalitis, intractable epilepsy, and hemispheric atrophy. The co-expression of EBV and HHV6 was detected in neurons and astrocytes in the brain tissue, accompanied by a high frequency of CD8⁺ T cells. Our results suggest that EBV and HHV6 infection and the activation of CD8⁺ T cells are involved in the pathogenesis of RE.     

Perinatal Vertical Transmission of Chikungunya Virus in Ruili,a Town on the Border between China and Myanmar

正Dear Editor,Chikungunya virus (CHIKV), an arbovirus in the family of Togaviridae, genus Alphavirus, is transmitted by the A.aegyptii or A. albopictus mosquito, and causes disease in humans characterized by fever, rash, and arthralgia (Silva and Dermody 2017; Suhrbier 2019). It was first reported in 1953 in Tanzania, and caused only a few outbreaks and sporadic cases in Africa and Asia in last century. However, in the epidemic in 2004, CHIKV acquired mutations that conferred enhanced transmission by the A. albopictus mosquito(Schuffenecker et al. 2006). Since then, it has successively caused outbreaks in Africa, the Indian Ocean, South East Asia, the South America, and Europe (Zeller et al. 2016).     

Development of a Novel Reverse Transcription Loop-Mediated Isothermal Amplification Method for Rapid Detection of SARS-CoV-2

In conclusion, the novel visual RT-LAMP assay is a simple, rapid, and sensitive approach for detection of SARS-CoV-2, and it is ready for application in primary care and community hospitals or health care centers, and even patients' own houses in response to the current SARS-CoV-2 epidemic because the assay does not require sophisticated equipment and skilled personnel. Furthermore, it is also ready to be used in fields for screening samples from wild animals and environments to facilitate the identification of potential intermediate hosts that mediate the cross-species transmission of SARS-CoV-2 from bats to humans.