大叶千斤拔的微波预处理-超声波提取工艺及其抑菌活性研究

对大叶千斤拔的微波预处理-超声波提取工艺及其抑菌活性进行研究。以染料木素得率和染料木苷得率为考察指标,通过单因素实验与正交实验优选大叶千斤拔中染料木苷和染料木素的最佳提取工艺,并对微波预处理-超声波提取法、超声波提取法和热水浸提法进行了对比研究,同时研究大叶千斤拔提取液和染料木素的抑菌活性。最佳提取工艺条件为:微波功率700 W,超声波功率200 W,解析剂比7∶1(m L/g),微波时间180 s,乙醇为提取溶剂,乙醇体积分数90%,液料比35∶1(m L/g),提取温度80℃,提取时间15 min。该工艺条件下,染料木苷得率为0.9047 mg/g,染料木素得率为0.4834 mg/g,总得率为1.3881 mg/g,优于超声波提取法和热水浸提法。在实验范围内染料木素和大叶千斤拔提取液对3种常见菌的抑制作用大小均为金黄色葡萄球菌枯草芽孢杆菌大肠杆菌,但染料木素对大肠杆菌无明显抑制作用。微波预处理-超声波提取法具有省时高效的特点,特别适用于大叶千斤拔染料木苷和染料木素的提取,大叶千斤拔提取液具有良好的抑菌活性,可作为天然的食品防腐剂。     

紫花苜蓿中4种黄酮类化合物抗氧化活性的DFT研究

为研究紫花苜蓿中4种黄酮类化合物抗氧化活性大小,运用密度泛函理论(DFT)方法在B3LYP/6-311++G(d,p)水平下研究了紫花苜蓿中四个活性黄酮化合物槲皮素、木犀草素、染料木素、芒柄花黄素的电子结构、自由基电子几何结构、酚羟基氢氧键离解能(BDE)以及分子前线轨道的能级差。通过数据分析,初步判断出这四个黄酮类化合物的抗氧化活性的大小顺序为:槲皮素木犀草素染料木素芒柄花黄素。理论预测结果与文献报道的实验结果一致。本研究结果表明DFT方法可为天然黄酮类抗氧化剂的筛选提供理论指导。     

基于文献计量的染料木素最新研究现状分析

目的:通过分析SCIE中染料木素领域相关论文,了解目前染料木素研究的现状与发展趋势。方法:利用Web of Science,从载文量、作者、地区与机构、关键词等角度统计分析;结果:共检索出9,446篇相关文献,涉及26222位作者及18个国家(地区)与4015个科研机构;染料木素专题学科发展趋于成熟,拥有一支实力雄厚、造诣较深的影响力较大的核心作者群。美国、日本、德国、中国、韩国、英格兰、加拿大、意大利、法国、台湾成为染料木素研究的中心国家和地区。染料木素生理学功能、提取分离方法、分析方法、药理作用、结构修饰等方面的研究为目前染料木素专题研究的主要内容。结论:染料木素该学科需要在临床实践中进一步发展成熟,生物利用度需得到进一步的提高。     

茉莉酸甲酯对木豆不定根染料木素含量及抗氧化系统影响

为探讨茉莉酸甲酯(Methyl Jasmonate,MJ)对木豆不定根影响,研究了茉莉酸甲酯的不同浓度及处理时间对木豆不定根中染料木素的含量及抗氧化系统的影响。研究结果表明,诱导子的浓度和处理时间对不定根中染料木素的含量有重要影响。在MJ浓度为100μmol·L^-1,处理时间为48 h时,染料木素的含量最高,为1.38 mg·g^-1,是对照组的4.03倍。在此基础上,研究了100μmol·L^-1的MJ处理对木豆不定根抗氧化系统的影响,结果表明,MJ处理的木豆不定根明显发生了氧化胁迫,O_2^-速率、H_2O_2和MDA含量明显升高,同时不定根中SOD和POD活性明显升高,但是抗氧化酶活性的提高并未消除不定根的氧化胁迫,这种氧化胁迫导致了木豆不定根次生代谢产物合成能力提高。     

染料木素抑制人胰腺癌细胞株PANC-1细胞增殖机制的研究

目的探讨不同浓度染料木素对胰腺癌细胞作用及其抑癌基因表达的研究。方法本实验共分实验组(80,120,160,200μmol/L)的染料木素、空白对照组(PBS)和标准对照(吉西他滨)。各组培养基处理细胞12,24,36,48,60 h后,细胞计数试剂盒(CCK-8)法检测人胰腺癌细胞株PANC-1在染料木素作用下的增殖活性;流式细胞术检测人胰腺癌细胞株PANC-1在染料木素木素作用下的凋亡细胞百分率;用逆转录-聚合酶连反应(RTPCR)方法测定P53及P21抑癌基因的表达;Western-blot法检测抑癌基因P53和P21的蛋白表达水平。细胞凋亡与细胞基因mRNA采用的是LSD法,细胞增殖数据采用的是配对t检验。结果流式细胞术显示,人胰腺癌细胞株PANC-1处理后60 h时在不同浓度(80,120,160,200μmol/L)的染料木素作用下细胞凋亡率分别为(3.72±1.58)﹪、(35.98±3.76)﹪、(51.36±4.32)﹪和(64.10±2.09)﹪。吉西他滨(gemcitabine,GEM)组为(43.45±5.28)﹪,不同浓度染料木素组与标准对照组间比较差异有统计学意义(均P<0.01);细胞增殖效果:160μmol/L与200μmol/L、120μmol/L与200μmol/L、200μmol/L与吉西他滨组之间比较,均有统计学意义(P<0.01),而160μmol/L与吉西他滨组比较无统计学意义(P>0.05);Western-blot检测蛋白水平显示160μmol/L和200μmol/L染料木素相对于空白对照能够明显的增强抑癌基因P21和P53的蛋白水平的表达,相对于标准组没有明显的差异。结论染料木素可以抑制人胰腺癌细胞株PANC-1增殖,并且初步探索了这种抑制作用表现出浓度及时间依赖性。     

RP-HPLC法测定怀槐中染料木素和芒柄花黄素含量

怀槐(Maackia amurensis Rupr.et Maxim.)广泛分布于中国东北三省及内蒙古等地,尤以黑龙江省为多.怀槐作为民间药,其茎、枝可治疗风湿性关节炎; 叶、枝皮可治疗肿瘤; 内皮可治疗深度伤口及久不愈合的溃疡.另外,怀槐树皮在民间还作为祛风湿、消炎、镇痛、健胃、止血等药广泛应用,疗效甚佳.从怀槐的根、枝、叶、果实和心材中分别分得异黄酮、生物碱、NC442类化合物,据报道,其中的异黄酮类化合物表现出对心血管系统的复合作用和明显的抗肿瘤活性[1].作者在对怀槐进行系统的化学成分研究过程中,分离鉴定了9个异黄酮类化合物[2,3],并进行了抑制肿瘤细胞增殖作用研究[4],其中,染料木素(genistein)对胃腺癌细胞(BGC)增殖有一定程度的抑制作用,芒柄花黄素(formononetin)则对白血病细胞(HL-60)增殖有一定的抑制作用.染料木素和芒柄花黄素作为马鞍树属(Maackia Rupr.)植物中普遍存在的2个异黄酮类化合物,其活性研究日益受到重视.采用HPLC法测定染料木素等异黄酮类化合物含量在大豆等其他植物中曾有文献报道[5].为了尽早开发怀槐资源,同时为其资源的综合利用提供科学依据,本文采用HPLC法对怀槐不同部位的染料木素和芒柄花黄素2个有效成分进行了含量测定.     

染料木素的乳糖糖苷化修饰及其产物的结构表征

为了改善染料木素在机体内作用的靶向性,本文研究了用具有与肿瘤细胞表面受体定向结合的乳糖来修饰染料木素。采用相转移催化法,首次合成了两种新的化合物:染料木素7-O-β-D-吡喃乳糖苷(4)和染料木素7,4′-二-O-β-D-吡喃乳糖苷(5),并对其进行了IR、MS、1HNMR和13C NMR结构表征。     

高效液相色谱法测定大鼠血清染料木素浓度

目的:建立大鼠血清中染料木素浓度的HPLC测定方法.方法:大鼠血清以叔丁基甲醚萃取,萃取物用氮气吹干后,用甲醇溶解用于色谱分析.色谱条件:采用Thermo C18柱(250ram×4.6mm,5μm);以乙腈-0.02mol/L磷酸二氢钾(35:65,pH=4.3)为流动相;流速为1.0mL/min;检测波长为260hm;柱温为40℃;进样量为10μL.结果:染料木素最低检测浓度为0.01mg/L;标准曲线线性范围为0.01～10.00μg/mL(r=0.9998);相对回收率为(101.31±3.47)%;日内RSD与日间RSD均小于10.00%.结论:该方法简便、快速、灵敏度高,重现性及稳定性较好,适用于大鼠血清染料木素浓度测定和药代动力学的研究.     

兔肠道大豆异黄酮还原菌株的分离鉴定及其转化特性

【目的】从兔新鲜粪样中分离对大豆异黄酮黄豆苷原和染料木素具有转化作用的特定细菌菌株。【方法】在厌氧工作站内对獭兔新鲜粪样进行梯度稀释后涂板,挑取单菌落与底物黄豆苷原和染料木素分别厌氧混合培养,用高效液相色谱检测底物被转化情况。【结果】分离得到一株对大豆异黄酮黄豆苷原和染料木素均具有转化作用的革兰氏阳性严格厌氧细菌菌株AUH-JLR41(KJ188150)。根据产物的高效液相保留时间、紫外吸收图谱和质谱分析结果,将菌株AUH-JLR41代谢底物黄豆苷原和染料木素生成的产物分别鉴定为二氢黄豆苷原和二氢染料木素。经手性高效液相系统检测,产物二氢黄豆苷原和二氢染料木素均呈现两个等面积物质峰,表明这两个产物的对映体过量率均为0。通过转化动态研究发现,菌株AUH-JLR41分别在底物黄豆苷原和染料木素加入48 h和72 h后将底物全部转化为产物,该菌株能转化底物黄豆苷原和染料木素的最大浓度均为0.6 mmol/L。经BLAST比对,菌株AUH-JLR41的16S r RNA基因序列与斯奈克氏菌属菌株Slackia equolifaciens DZE(EU377663)的相似性高达99.6%。【结论】兔肠道分离的斯奈克氏菌属菌株Slackia sp.AUH-JLR41在厌氧条件下能将大豆异黄酮黄豆苷原和染料木素分别还原为二氢黄豆苷原和二氢染料木素。     

新型染料木素磺酸酯的前药判定与大鼠体内生物利用度

为寻找染料木素(GE)新的前药,采用建立的生物样品中药物浓度测定的液相色谱法对新型大豆异黄酮染料木素磺酸酯(GB)进行前药判定以及大鼠体内药物动力学研究,以考察前药中染料木素的口服生物利用度是否改善.在大鼠体内药物代谢实验中,灌胃给予GB的大鼠血浆中能检测到明显的GE.在临床前药物动力学实验中,该前体静注给药和以40 mg/kg灌胃药后,GE在大鼠体内的动力学过程均符合一室模型.GB中GE的相对口服生物利用度为原药的110.9％.研究表明,相对于原药GE,前药中GE的相对口服生物利用度达到预期的改善,该前药有进一步研究意义.     

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.     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.     

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).