天花粉中总三萜皂苷的含量分析

目的:对天花粉中总三萜皂苷含量进行测定,为天花粉质量评价提供依据。方法:选用熊果酸为对照品,5%香草醛-冰醋酸和高氯酸为显色剂,以紫外分光光度法测定天花粉中总三萜皂苷的含量。结果:标品在16～48μg范围内有良好的线性关系(r=0.9905)。样品在10～40min内稳定,加样回收率为97.22%,RSD=1.59。结论:该方法操作简便,快速,灵敏度高和重复性好,可用于天花粉及其相关产品的质量控制。     

新疆阿魏中总黄酮的提取分离及含量测定

以芦丁为对照品,NaNO2-AlCl3-NaOH体系为显色剂分光光度法测定新疆阿魏的总黄酮类含量。通过回流法和超声法提取新疆阿魏中的总黄酮,比较两种提取方法,从而得到最佳的提取方法,超声法是合适的提取方法。确定了提取总黄酮的适当溶剂、时间和显色剂用量。建立了芦丁浓度-吸光度关系的回归方程为A=9．2500C-0．0193,r=0．9993。平均回收率为98．73％。RSD为1．04％（n=6）。方法简单、可行、重现性好。     

黑灵芝中三萜及其皂苷类化合物总量的光度测定

采用正交试验法优化了香草醛高氯酸法测定黑灵芝三萜及其皂苷类化合物总量的显色条件,建立了测定黑灵芝中三萜及其皂苷类化合物总量的分光光度法,检测波长为550 nm,回归方程为:A=0.0093C-0.0032(μg),R2=0.9986(n=6),齐墩果酸对照品在0～128.4μg范围内呈良好线性关系,RSD为4.09%,对样品进行加标实验,平均回收率为103.9%.用于黑灵芝中三萜及其皂苷类成分的溶剂回流提取、超声提取的测定,结果证明这种方法是可靠的,可供灵芝质量控制.     

核桃仁内隔膜中总黄酮最佳提取工艺的研究

目的:从核桃仁内隔膜中提取并测定总黄酮含量,选择最佳提取工艺条件.方法:以芦丁为对照品,用分光光度法在最大吸收波长510nm对其含量进行测定.结果:测得样品中总黄酮含量C=6.430%,最佳提取工艺:乙醇浓度为75%、料液比为1:40、超声提取时间为60min、超声提取温度为80℃.结论:选用芦丁为对照品应用于紫外分光光度法测定核桃仁内隔膜总黄酮含量准确度较高,方法简单,可作为测定核桃仁内隔膜中黄酮含量的一种手段.     

正交试验优选超声提取芦笋总皂苷的工艺

目的:优选超声提取芦笋总皂苷的最佳工艺。方法:以高氯酸作为显色剂,用紫外分光光度法测定芦笋中总皂苷的含量,并以提取率为评价指标,采用单因素实验和正交试验优选最佳提取工艺。结果:芦笋总皂苷超声提取的最佳工艺为乙醇浓度70%,料液比1:15(W/V),超声时间50 min,超声温度40℃。结论:该提取工艺可行,为芦笋总皂苷的进一步研究提供了依据。     

土茯苓中总黄酮的含量测定方法研究

目的:建立土茯苓总黄酮的含量测定方法。方法:采用70%乙醇超声提取工艺和可见分光光度法测定土茯苓中总黄酮的含量,以芦丁为对照品,在500 nm波长处测量。结果:芦丁在0.008～0.048 mg.mL-1范围内线性关系良好(r=1.000),平均加样回收率(n=6)以芦丁计为98.34%,RSD为3.4%。结论:此方法操作简单,精密度、稳定性和重复性良好,可用于土茯苓总黄酮含量测定。     

肉苁蓉总黄酮含量的测定

目的：从肉苁蓉中提取并测定总黄酮含量,选择最佳提取工艺条件。方法：以芦丁为对照品,用分光光度法在最大吸收波长510nm对其含量进行测定。结果：测得样品中总黄酮含量C=9．33％,最佳提取工艺：乙醇浓度为70％、料液比1：40、回流时间2h、回流温度70℃。结论：选用芦丁为对照品应用于紫外分光光度法测定肉苁蓉总黄酮含量准确度较高,方法简单,是切实可行含量测定方法。     

超声提取-分光光度法测定浙江雪胆中总皂苷含量

超声波提取浙江雪胆总皂苷,运用分光光度法对浙江雪胆中总皂苷的含量进行测定。正交设计优选比色条件,以齐墩果酸-28-O--αL-鼠李吡喃糖基(1→4)--βD-葡萄吡喃糖基(1→6)--βD-葡萄吡喃糖甙(cussonodide B)为标准品,利用香草醛-醋酸显色体系,在550 nm处检测。浓度在3.43~17.17μg/mL范围内呈良好的线性关系,其回归方程为A=0.03350*C(μg/mL)-0.06595,相关系数R=0.9995,浙江雪胆中总皂苷的含量为0.34%,加样回收率99.29%,RSD=0.99%。本方法简便、快速、准确、可靠。     

龙牙楤木总皂苷含量测定及其抗炎镇痛活性评价

建立了一种龙牙楤木中总皂苷的含量测定方法,比较了龙牙楤木根皮和茎皮中总皂苷含量,并研究了龙牙愡木的抗炎镇痛作用。采用超声辅助提取,用紫外-可见分光光度法,以齐墩果酸为对照品建立标准曲线;以5%香草醛-冰醋酸为显色剂,检测波长550nm,用比色法测定总皂苷含量。结果显示所建立的方法稳定可靠,龙牙楤木不同部位皂苷含量差异较大,根皮总皂苷含量为43.50mg/g,而茎皮为24.38mg/g。总皂苷在0.02~0.10mg/mL(R~2=0.999 6)质量浓度范围内呈良好线性关系,根皮和茎皮的平均回收率分别为100.12%(RSD=1.10%)和99.84%(RSD=1.77%)。采用醋酸致小鼠扭体试验和耳廓肿胀试验研究龙牙楤木总皂苷抗炎镇痛活性,结果表明龙牙楤木总皂苷能显著减轻醋酸对试验小鼠内脏所致的疼痛(P<0.05)和降低由二甲苯所致实验小鼠耳廓的肿胀程度(P<0.05),显示出较强的抗炎镇痛作用,且根皮的作用效果比茎皮好。龙牙愡木抗炎镇痛活性可能与其总皂苷含量呈正相关。建立的总皂苷含量测定方法简便、准确、重现性好,可作为龙牙楤木根皮与茎皮中总皂苷的含量测定方法。     

土茯苓中总黄酮的含量测定方法研究

目的：建立土茯苓总黄酮的含量测定方法。方法：采用70%乙醇超声提取工艺和可见分光光度法测定土茯苓中总黄酮的含量,以芦丁为对照品,在500 nm波长处测量。结果：芦丁在0.008～0.048 mg.mL-1范围内线性关系良好（r=1.000）,平均加样回收率（n=6）以芦丁计为98.34%,RSD为3.4%。结论：此方法操作简单,精密度、稳定性和重复性良好,可用于土茯苓总黄酮含量测定。     

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