不同地区红景天植物红景天苷含量比较研究

采用高效液相色谱法(HPLC)测定了6种不同地区红景天植物红景天苷含量.以甲醇为提取溶剂,室温超声提取45 min,HPLC测定条件:岛津C18柱(4.6×250 mm,5 μm);流动相为甲醇∶水=3∶7;柱温25℃;检测波长为275 nm.结果表明,红景天苷含量分别为:大花红景天0.36%,狭叶红景天(狮子七)0.32%,宽果红景天0.14%,白三七0.04%,在小丛红景天、洮河红景天中未检测到红景天苷.     

化橘红果实生长发育过程中类黄酮的动态变化

该研究建立了化橘红(Citrus grandis cv.‘Tomentosa’)果实中4种类黄酮成分的提取分离、HPLC定量和指纹图谱分析方法,利用该方法测定了果实生长发育过程中类黄酮的动态变化。结果表明,用60%乙醇超声辅助提取果实干燥粉末2小时,柚皮苷提取率达到98%以上。用HPLC分离和测定提取物中柚皮苷、野漆树苷、柚皮素和芹菜素的含量及其指纹图谱。结果显示,15–60天不同果龄的果实中类黄酮含量(占果实干重)随着果龄的增大而降低,柚皮苷、野漆树苷、柚皮素和芹菜素分别从52.5%、0.74%、0.57%和0.23%降低至16.1%、0.11%、0.06%和0.03%;每果中类黄酮总量则随着果龄的增加而大幅提高,从15天的0.55 g提高至60天的7.99 g。上述研究结果表明,果龄对化橘红类黄酮含量、产量及药材质量均有很大的影响。该研究为化橘红的工业生产和质量监控提供了重要依据。     

青海油菜蜂花粉黄酮类化合物含量的研究

采用正交试验设计,研究了青海油菜蜂花粉中黄酮类化合物的最佳提取条件,分别采用HPLC法和比色法测定了黄酮类化合物的含量。最佳提取条件是选用95％的乙醇作为溶剂,以10倍总量的乙醇用量,水浴热回流提取。以槲皮素、山奈酚、异鼠李素为对照品,采用HPLC法,测定出黄酮类化合物平均含量为3．194％;以芦丁为对照物,采用比色法,测定出总黄酮平均含量为3．70％。     

黄连副产物中生物碱含量测定及提取工艺研究

目的:用HPLC对黄连生产副产物的生物碱含量进行测定,探究黄连生物碱在叶柄和须根中的分布。选择副产物生物碱的最佳提取工艺回收利用生物碱。方法:采用HPLC法建立黄连生物碱的含量测定方法,结合HPLC指纹图谱对黄连生产副产物进行生物碱含量测定。采用单因素试验法,分别对提取酸度、料液比和提取次数进行试验,分析并选取最佳提取条件。结果:黄连生产副产物中黄连生物碱的含量非常可观,其中黄连须含有大量的黄连生物碱,值得进一步开发利用。提取条件为:H2SO4浓度1.5%;料液比1∶15;提取时间1 h。结论:从黄连生物碱含量、资源的综合及可持续利用角度考虑,黄连生产副产物有很好的商业利用前景。     

HPLC法测定抗宫炎凝胶剂中金石蚕苷含量的研究

目的:采用高效液相色谱法(HPLC)测定抗宫炎凝胶剂中金石蚕苷的含量,为制定其质量标准提供基础。方法:采用十八烷基硅烷键合胶为填充剂,乙腈-0.5%磷酸(18:82)为流动相;检测波长为332 nm;流速为1.0 ml/min,探讨HPLC测定抗宫炎凝胶剂中金石蚕苷含量的专属性、精密度、稳定性、重现性等。结果:金石蚕苷在0.104~0.468 mg/ml范围内呈良好的线性关系(r=0.9999),平均回收率为99.76%,RSD为1.56%。结论:采用HPLC测定抗宫炎凝胶剂中金石蚕苷含量的专属性、精密度、稳定性、重现性均良好,该方法简便可靠,可用于抗宫炎凝胶剂的质量标准的研究。     

复方新会陈皮含片药材提取工艺优选

目的 优选复方新会陈皮含片中甘草、桔梗药材的水提取工艺条件。方法 采用单因素试验和正交试验法,以得膏率和甘草中指标性成分甘草苷、甘草酸的保留率为考察指标,高效液相色谱法测定甘草苷、甘草酸的含量;以加水量、煎煮次数、煎煮时间、浸泡时间为考察因素,优选提取工艺条件。结果 甘草、桔梗药材的水煮提取工艺优选条件分别为加水量9、8、8倍煎煮3次,每次2 h,不浸泡。验证试验指标成分甘草苷和甘草酸保留率分别约为87.0%、64.0%。结论 优选的提取工艺得膏率、甘草苷、甘草酸的含量较高,提取工艺稳定、合理可行。     

高效液相色谱法测定妇血荣胶囊中芍药苷的含量

目的:建立妇血荣胶囊中芍药苷含量的HPLC检测方法.方法:采用甲醇提取样品;色谱条件:Alltech ODS柱(5μm,250mm×4.6 mm);流动相为乙腈-水(16:84,v/v);检测波长为230 nm.结果:线性范围为24.3～218.7 μg.mL-1(r=0.9999),平均回收率为101.21%,RSD为0.80%.结论:高效液相色谱法简单易行,准确,灵敏度高,适用于妇血荣胶囊中芍药苷的含量测定.     

正交试验优化乙醇回流提取积雪草苷的工艺研究

为了优化积雪草中积雪草苷的提取工艺,本研究采用乙醇回流法,以积雪液草苷含量为研究指标,在单因素试验的基础上采用正交试验设计,考察乙醇浓度、液料比、粉碎粒度以及提取时间等因素对提取结果的影响。结果表明,积雪草苷的最佳提取工艺条件为:乙醇浓度70%、液料比10∶1、粉碎粒度140目、提取时间6h,该工艺条件下积雪草苷的提取含量达到8.32mg·g-1。     

河南和山西连翘叶中总木脂素、连翘酯苷A、连翘酯苷B和连翘苷的含量比较北大核心CSCD

测定河南和山西连翘叶中总木脂素、连翘酯苷A、连翘酯苷B和连翘苷含量。采用分光光度法测定连翘叶中总木脂素含量,结果显示山西连翘叶高于河南连翘叶总木脂素含量。采用高效液相色谱法(HPLC)测定连翘叶中连翘酯苷A、连翘酯苷B和连翘苷的含量。连翘酯苷A平均回收率为99.6%,RSD为1.23%;连翘酯苷B平均回收率为101.3%,RSD为1.74%;连翘苷平均回收率为102.3%,RSD为2.58%;连翘叶中连翘酯苷A和连翘苷的含量较高,并且不同产地连翘叶中连翘苷含量差异较大;另外对于富含连翘酯苷和连翘苷的连翘叶能否代替果实或者与果实合并用药有待于进一步研究。     

桑枝中桑皮苷A的提取工艺优化及其含量测定

本文采用响应面法优化桑枝中桑皮苷A的超声提取工艺。在单因素试验的基础上,以桑枝中桑皮苷A为响应值,考察了甲醇比例、溶剂体积、超声时间及超声温度对桑皮苷A含量测定的影响。研究表明,桑枝中桑皮苷A的最佳提取工艺条件为:60%甲醇水溶液,溶剂体积55 mL,超声时间40 min,超声温度35℃。在该条件下,桑枝中桑皮苷A质量分数为7. 63 mg/g,与预测值7. 64 mg/g接近。桑皮苷A在0. 012 8~0. 064 mg/mL范围呈良好的线性关系(r=0. 999 3),9批桑枝药材中桑皮苷A含量范围为4. 97~13. 14 mg/g。结果表明根据Box-Behnken模型、采用响应面分析法得到的桑枝中桑皮苷A提取优化工艺准确可靠,可用于检测桑枝中桑皮苷A的含量。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

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.     

Synthesis and antimicrobial studies of hydrazone derivatives of 4-[3-(2,4-difluorophenyl)-4-formyl-1H-pyrazol-1-yl]benzoic acid and 4-[3-(3,4-difluorophenyl)-4-formyl-1H-pyrazol-1-yl]benzoic acid

Microbial resistance to antibiotics is an unresolved global concern, which needs urgent and coordinated action. One of the guidelines of the Centers for Disease Control and Preventions (CDC) to combat antibiotic resistance is the development of new antibiotics to treat drug-resistant bacteria. In our effort to find new antibiotics, we report the synthesis and antimicrobial studies of 30 new pyrazole derivatives. These novel molecules have been synthesized by using readily available starting materials and benign reaction conditions. Some of these molecules have shown activity with MIC values as low as 0.78?µg/mL against four bacterial strains; Staphylococcus aureus, methicillin-resistant S. aureus, Bacillus subtilis, and Acinetobacter baumannii. Furthermore, active molecules are non-toxic to mammalian cell line.

     

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.     

Novel compounds with potent CDK9 inhibitory activity for the treatment of myeloma

Cyclin-dependent kinases (CDKs) and Polo-like kinases (PLKs) play key role in the regulation of the cell cycle. The aim of our study was originally the further development of our recently discovered polo-like kinase 1 (PLK1) inhibitors. A series of new 2,4-disubstituted pyrimidine derivatives were synthesized around the original hit, but their PLK1 inhibitory activity was very poor. However the novel compounds showed nanomolar CDK9 inhibitory activity and very good antiproliferative effect on multiple myeloma cell lines (RPMI-8226).