美登木内生真菌lr88蒽醌类代谢产物的研究

美登木内生真菌lr88采自云南西双版纳美登木的叶中.从该菌的固体培养物中分离得到3个蒽醌类成分,通过波谱分析鉴定为1-羟基-8-甲氧基蒽醌(1),1,3,6,8-四羟基蒽醌(2)及1,8-二羟基蒽醌(3).     

不同光质对毛脉酸模中蒽醌类成分的影响

通过红色、黄色、绿色、蓝色滤光膜对毛脉酸模进行遮膜处理。采用高效液相色谱法对毛脉酸模根样品中的蒽醌类成分含量进行测定,研究光质对毛脉酸模根次生代谢产物蒽醌类成分的影响。进行了方差分析。二年生黄膜处理中蒽醌类成分含量显著性高于处理组及空白组。一年生空白组及对照组中蒽醌类成分含量显著性高于处理组。结果表明黄膜处理显著提高二年生毛脉酸模中中蒽醌类成分含量。     

虎杖根茎中蒽醌类成分的体外抗氧化活性

采用超声波提取法用体积分数80%乙醇对虎杖(Reynoutriajaponica Houtt.)根茎中的蒽醌类成分进行粗提,并利用D101大孔吸附树脂对粗提液进行纯化.以Vc为阳性对照,采用体外动物实验研究了虎杖根茎中蒽醌类成分对小白鼠肝组织匀浆中谷胱甘肽过氧化物酶(GSH-px)活力及对H2O2诱导的MDA含量和红细胞氧化溶血的影响,并采用化学模拟体系分析了其对DPPH·自由基的清除能力、对Fe3+的还原能力以及与Fe2+的螯合能力.结果表明:虎杖根茎中蒽醌类成分含量丰富,粗提物含量达到55.86 mg·g-1,纯化后含量达到44.77 mg·g-1.质量浓度l0、20、30和40μg·mL-1的蒽醌类成分可显著增强GSH-px活力、降低由H2O2诱导产生的MDA含量,并对H2O2诱导产生的红细胞氧化溶血有较强的抑制作用;质量浓度2、4、6和8μg·mL-1的蒽醌类成分对DPPH·自由基具有良好的清除能力,质量浓度6、8、12和16μg·mL-1蒽醌类成分对Fe3+具有较强的还原能力,而质量浓度5、10、15和20μg·mL-1蒽醌类成分对Fe2+则具有很强的螯合能力.随质量浓度的提高,虎杖蒽醌类成分及阳性对照Vc的各项抗氧化活性指标均逐渐增强,呈现出明显的量效关系,且虎杖根茎中蒽醌类成分的各项抗氧化指标均优于相同质量浓度的Vc.研究结果显示:虎杖根茎中的蒽醌类成分具有较强的抗氧化活性,不仅能够直接清除过量的自由基,也可以通过增强体内的抗氧化系统以抑制自由基的产生.结合他人研究结果,对虎杖资源的开发利用提出了一些建议.     

何首乌不同器官和组织中蒽醌和茋类化合物的分布

目的探讨何首乌(Polygonum multiflorum Thunb.)不同营养器官和组织中蒽醌类和茋类化合物的分布,为合理利用何首乌提供科学依据.方法采用数码显微鉴定和TLC对何首乌的不同器官和组织部位进行了比较研究.结果从器官来看,何首乌藤茎、地下茎和块根中均含有蒽醌(大黄素和大黄素甲醚)和芪类(2,3,5,4'-四羟基二苯乙烯-2-O-β-D-葡萄糖苷)而叶和嫩茎则不舍;从组织部位来看,蒽醌类成分主要分布于韧皮部,而茋类成分主要分布于周皮和韧皮部,木质部最少.结论蒽醌类和茋类成分的产生与周皮的形成有一定的关系.蒽醌类化合物的含量可能与韧皮部的发达程度有关,茋类化合物主要产生和贮藏于薄壁细胞中.     

盐酸米托蒽醌聚乙二醇化脂质体的制备及包封率考察

目的:制备盐酸米托蒽醌聚乙二醇化(PEG化)脂质体,建立包封率测定方法.方法:采用乙醇注入结合高压均质法制备空白PEG化脂质体;以铵根离子梯度法进行主动载药制备盐酸米托蒽醌PEG化脂质体;采用G-25葡聚糖凝胶色谱分离脂质体和游离药物;使用紫外-可见分光光度法测定脂质体的包封率.结果:空白脂质体平均粒径为88.7nm,载药后粒径为95.3nm;在所建立色谱条件下,脂质体与游离米托蒽醌分离良好;盐酸米托蒽醌在0.5～10μg·ml-1范围内线性关系良好(R 2=0.9997),精密度高;脂质体的平均包封率大于96％.结论:乙醇注入-高压均质法结合铵根离子主动载药法适用于制备盐酸米托蒽醌PEG化脂质体;所建立分析方法简单快捷、准确可靠,可用于盐酸米托蒽醌长循环脂质体包封率的测定.     

毛脉酸模内生真菌蒽醌类次生代谢产物的筛选及含量分析

本文通过对毛脉酸模内生真菌的发酵培养得到其次生代谢产物,采用HPLC法对内生真菌中蒽醌类成分进行筛选。以大黄素、大黄酸、大黄酚、大黄素甲醚、芦荟大黄素五种蒽醌类成分为参照,筛选出3株真菌含大黄素、3株真菌含大黄酸、5株真菌含芦荟大黄素,其中含量最高为683μg/g、最低为8μg/g。将各菌株所含成分与各菌株分离部位的相应成分进行比较,相对宿主植物而言各菌株均有较高的含量。本实验分析方法准确、快捷,适用于毛脉酸模内生真菌的代谢产物研究。     

何首乌不同器官和组织中蒽醌和芪类化合物的分布

目的探讨何首乌（Polygonum multiflorumThunb．）不同营养器官和组织中葸醌类和芪类化合物的分布,为合理利用何首乌提供科学依据。方法采用数码显微鉴定和TLC对何首乌的不同器官和组织部位进行了比较研究。结果从器官来看,何首乌藤茎、地下茎和块根中均含有蒽醌（大黄素和大黄素甲醚）和芪类（2,3,5,4’-四羟基二苯乙烯-2-O-β-D-葡萄糖苷）而叶和嫩茎则不含;从组织部位来看,蒽醌类成分主要分布于韧皮部,而芪类成分主要分布于周皮和韧皮部,木质部最少。结论蒽醌类和芪类成分的产生与周皮的形成有一定的关系,蒽醌类化合物的含量可能与韧皮部的发达程度有关,芪类化合物主要产生和贮藏于薄壁细胞中。     

诺丽发酵果汁中抗氧化物质的研究

本实验针对茜草科植物诺丽的发酵果汁中抗氧化物质进行了定性和定量研究。采用系统预实验法对其不同极性的洗脱部位可能含有的化学成分进行预实验,探索了各个部位的化学成分。采用DPPH·自由基清除、ABTS+·自由基清除和FRAP三种实验方法对各部位洗脱物的抗氧化活性进行了测定,结果显示50%~90%乙醇洗脱部位抗氧化能力最强,此部位主要含有多酚类、黄酮类、香豆素内酯类和蒽醌类成分,并且研究表明抗氧化能力与多酚成分的含量成极显著相关。本研究结果表明多酚类物质是诺丽发酵果汁发挥抗氧化作用的主要功能成分。     

糙叶五加正丁醇萃取部位抗炎活性成分研究

本文对糙叶五加果实正丁醇萃取物的抗炎活性成分进行研究.采用硅胶柱色谱、C18柱色谱、LH-20型羟丙基葡聚糖凝胶(Sephadex LH-20)柱色谱、半制备液相及重结晶等方法进行分离纯化,利用波谱分析结合理化性质鉴定化合物的结构.从糙叶五加果实正丁醇萃取部位中分离鉴定出17个化合物,分别为槲皮素-3-O-β-D-吡喃...     

高速逆流色谱结合半制备液相色谱制备甘青青兰中3种活性成分

采用高速逆流色谱（HSCCC）结合液相色谱法制备甘青青兰（Dracocephalum tanguticum Maxim.）中绿原酸、胡麻甙-6″-乙酯、迷迭香酸,建立快速分离制备甘青青兰中活性成分的方法。采用半制备型高效液相色谱（SP-HPLC）富集甘青青兰乙酸乙酯萃取物中绿原酸、胡麻甙-6″-乙酯、迷迭香酸,再用制备液相（Pre-HPLC）和HSCCC对富集物进行分离纯化,获得54 mg化合物Ⅰ、130 mg化合物Ⅱ和200 mg化合物Ⅲ,纯度分别为96.9%、97.9%和95.1%,经核磁共振碳谱（¹³CNMR）和氢谱（¹HNMR）分别鉴定为绿原酸、胡麻甙-6″-乙酯和迷迭香酸。本实验方法适用于甘青青兰乙酸乙酯萃取物中绿原酸、胡麻甙-6″-乙酯和迷迭香酸的分离制备,并避免了传统分离方法操作繁多、试剂消耗量大、不可回收等弊端,为分离甘青青兰活性成分、制备对照品等研究提供了参考依据。     

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.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.