重楼排草的化学成分研究

从报春花科植物重楼排草（L.Paridiformis Frach）的全株中分离得到了7个化合物。应用各种理化方法及光谱分析鉴定其化学结构。分别鉴定为：希克拉敏A-3-O-｜β-D-吡喃木糖基．（1→2）-β-D-吡喃葡萄糖基-（1→4）-[β-D-吡喃葡萄糖基-（1→2）]｜}-α-L-吡喃阿拉伯糖苷（1）、3β-O-[β-D-吡喃木糖基-（1→2）-β-D-吡喃葡萄糖基-（1→4）]。[β-D-吡喃葡萄糖基-（1→2）]-α-L-吡喃阿拉伯糖基-16α-羟基-13β,28-环氧-齐墩果烷（2）、异鼠李素-3-O-[β-D-吡喃鼠李糖基-（1→）β-D-吡喃阿拉伯糖苷]（3）、槲皮素-3-O-[β-D-吡喃鼠李基-（1→4）-β-D-吡喃阿拉伯糖苷]（4）、β-香树素（5）、β-香树素乙酸酯（6）、三十二烷醇（7）。其中1、2、3、4均为首次从本植物中分离得到。     

排风藤中皂苷类化学成分研究

从茄属植物排风藤的全草中分离得到了4个皂苷类化合物,经鉴定分别为:25R-螺甾-3-O-[β-D-吡喃木糖基-(1→3)]-O－β-D-吡喃葡萄糖基-(1→2)-O-β-D-吡喃葡萄糖基-(1→4)-O-β-D-吡喃半乳糖苷(1),5α,25R-螺甾-3-O-[β-D-吡喃木糖基-(1→3)]-O-β-D-吡喃葡萄糖基-(1→2)-O－β-D-吡喃葡萄糖基-(1→4)-O-β-D-吡喃半乳糖苷(2),22α,25R-26-O-β-D-吡喃葡萄糖基-22-羟基-呋甾-△5-3β,26-二醇-3-O-β-D-吡喃葡萄糖基-(1→2)-O-[β-D-吡喃木糖基-(1→3)]-O-β-D-吡喃葡萄糖基-(1→4)-O-β-D-吡喃半乳糖苷(3),22α,25R-26-O-β-D-吡喃葡萄糖基-22-羟基-呋甾-△5-3β,26-二醇-3-O－β-D-吡喃葡萄糖基-(1→2)-O-β-D-吡喃葡萄糖基-(1→4)-O-β-D-吡喃葡萄糖苷(4).化合物1-4均为首次从排风藤中分离得到.     

传统中药漆姑草（Sagina japonica）中的C-27甾体成分

利用Diaion HP 20及硅胶柱层析进行化合物的分离,从乙酸乙酯萃取部位分离得到了4个化合物,借助多种光谱技术进行结构鉴定分别鉴定为(25R)-螺甾-5-烯-1β,3β-二醇1-O{O-α-L-鼠李吡喃糖苷-(1→2)-O-[β-D-木糖吡喃糖苷-(1→3)]1β-D-岩藻吡喃糖苷}(ophiopogonin D,1),(25R)-ruscogenin 1-O-[2-O-(乙酰基)-α-L-鼠李吡喃糖苷-(1→2)][β-D-木糖吡喃糖苷-(1→3)]-β-D-岩藻吡喃糖苷(2),(25R)-rascogenin 1-O-[3-0-(乙酰基)-α-L-鼠李吡喃糖苷-(1→2)][β-D-木糖吡喃糖苷-(1→3)]-β-D-岩藻吡喃糖苷(3),蜕皮甾酮(4).所有化合物均为首次从该植物中分得.     

风轮菜中一个新皂苷类化合物的结构鉴定

从风轮菜全草乙醇提取物的正丁醇萃取部分分离得到一皂苷类新化合物,通过谱学方法确定其结构为3β,16β,23,28-四羟基-11(12)-烯-齐墩果烷-3-O-[β-D-吡喃葡萄糖基(1→2)]-[β-D-吡喃葡萄糖基(1→3)]-β-D-吡喃夫糖苷(1),命名为风轮菜皂苷H.     

屏边三七根茎中的两个新的齐墩果酸皂甙

从屏边三七(Panax stipuleanatus Tsai et Feng)根茎中分离到二个齐墩果烷型新皂甙,命名为屏边三七甙(stipuleanoside)R_1和R_2,其化学结构经光谱分析和化学降解反应,分别确定为齐墩果酸-3-O-β-D-葡萄吡喃糖基(1→3)[α-L-阿拉伯呋喃糖基(1→4)]-β-D-葡萄吡喃糖醛酸甙(1)和齐墩果酸[28-O-β-D-葡萄吡喃糖基]-3-O-β-D-葡萄吡喃糖基(1→3)[α-L-阿拉伯呋喃糖基(1→4)]-β-D-葡萄吡喃糖醛酸甙(3)。     

无患子中两个新的大戟烷型三萜皂甙

从无患子科无患子(Sapindus mukorossi Gaertn.)根中分离到两个新的大戟烷型三萜皂甙Sapimukoside A (1) 和Sapimukoside B (2).运用波谱和化学方法鉴定它们的结构为3-O-α-L-鼠李吡喃糖基-(1→2)-[α-L-阿拉伯吡喃糖基-(1→3)]-β-D-葡萄吡喃糖基-21, 23R-epoxyl tirucall-7, 24R-diene-3β, 21-diol (1) 和3-O-α-L-鼠李吡喃糖基-(1→6)-β-D-葡萄吡喃糖基21, 23R-epoxyl tirucall-7, 24R-diene-3β, 21-diol (2).     

盾叶薯蓣地上部分的三个新甾体皂甙

从盾叶薯蓣Dioscorea zingiberensis Wright地上部分分离鉴定了四个甾体皂甙,经鉴定甙A为约莫皂甙元-3-O-[α-L-鼠李吡喃糖基(1→2)]-β-D-葡萄吡喃糖甙;甙B为24α-羟基约莫皂甙元-3-O-[α-L-鼠李吡喃糖基(1→2)]β-D-葡萄吡喃糖甙;甙C为约莫皂甙元-3-O-[α-L-鼠李吡喃糖基(1→2)][β-D-葡萄吡喃糖基(1→4)]-β-D-葡萄吡喃糖基;甙D为约莫皂甙元-3-O-[α-L-鼠李吡喃糖基(1→2)][β-D-葡萄吡喃糖基(1→3)]-β-D-葡萄吡喃糖甙。前三者为新化合物,分别命名为盾叶皂甙A_1、A_2、A_3(zingiberoside A_1、A_2、A_3),其中盾叶皂甙A_2的甙元为一新甾体皂甙元,命名为盾叶皂甙元(zingiberogenin)。     

金铁锁皂甙的研究

从金铁锁(Psammoslene tunicoides)根中分离到二个新的齐墩果烷型五环三萜皂甙Ⅰ、Ⅱ,经光谱测定和化学降解证明它们的化学结构为齐墩果烷-3α,16α-二羟基-12烯-23-酸-28-O-β-D-葡萄吡喃糖基(1—3)-β-D-葡萄吡喃糖基(1—6)-β-D-葡萄吡喃糖甙(Ⅰ)和齐墩果烷-3α,16α-二羟基-12烯-23-酸-28-O-β-D-葡萄吡喃糖基1—6[-β-D-葡萄吡喃糖基1—3]-β-D-葡萄吡喃糖甙(Ⅱ)。上述两个化合物的母核配基均为同一的物质,差异是糖的连接位置不相同。     

太白米中的甾体生物碱苷

对太白米的叶、大鳞茎和小鳞茎进行了化学成分系统预试,从大鳞茎中分离得到4个甾体生物碱苷,通过对其IR、FABMS、SIMS、1^HNMR、13^CNMR、DEPT、HMQC、HMBC和1^H-1^H COSY的综合解析鉴定了其中3个结构,它们分别为茄次碱-3-O-α-L-吡喃鼠李糖-(1→2)-β-D-吡喃葡萄糖苷(Ⅱ)、茄次碱-3-O-α-L-吡喃鼠李糖-(1→2)-[β-D-吡喃葡萄糖(1→4)]-β-D-吡喃葡萄糖苷(Ⅲ)和茄次碱-3-O-α-L-吡喃鼠李糖-(1→2)-[β-D-吡喃葡萄糖-(1→3)-β-D-吡喃葡萄糖(1→4)]-β-D-吡喃葡萄糖苷(IV)。     

黑刺菝葜中的甾体皂苷

从黑刺菝葜(Smitax scobinicaulis C.H.Wringh)根茎中再次分离得到2个新的甾体皂苷化合物,经理化、光谱分析及与标准样品对照,鉴定化合物Ⅲ为(25D)螺甾-5-烯-3β,17α,27-三羟基-3-O-β-D-吡喃葡萄糖-(1→4)-O-[α-L-吡喃阿拉伯糖(1→6)]-β-D-吡喃葡萄糖甙。化合物Ⅳ为(25D)螺甾-3β,17α,27-三羟基-3-O-β-D-吡喃葡萄糖-(1→4)-O-[α-L-吡喃阿拉伯糖(1→6)]-β-D-吡喃葡萄糖甙。     

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.