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)。     

滇产植物皂素成分的研究——Ⅹ.五指莲的两个新甾体皂甙(1)

从重楼属植物五指莲Paris axialis H.Li.根茎中分离到三个甾体皂甙,经化学降解,质谱,核磁共振谱分析,证明其中两个甙为新的化合物,即偏诺皂甙元-3-O-β-D-葡萄吡喃糖基(1→3)[α-L-鼠李吡喃糖基(1→2)]-β-D-葡萄吡喃糖甙(Ⅰ)和24α-羟基偏诺皂甙元-3-O-β-D-葡萄吡喃糖基(1→3)][α-L-鼠李吡喃糖基(1→2)]-β-D-葡萄吡喃糖(Ⅲ);另一个鉴定为薯芋皂甙元-3-O-β-D-葡萄吡喃糖基(1→3)[α-L-鼠李吡喃糖基(1→2)]-β-D-葡萄吡喃糖甙(Ⅱ)。     

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。     

滇重楼地上部分的甾体皂甙

从滇重楼Paris polyphylla Sm. var. yunnanensis (Fr.) H-M.地上部分分离得到3个甾体皂甙,经光谱测定和化学降解证明其化学结构分别为:偏诺皂甙元3O-α-L-鼠李吡喃糖基(1→2)〔α-L-鼠李吡喃糖基(1→4))-β-D-葡萄吡喃糖甙(A);孕甾-5,16-二烯-3β-醇-20-酮,3β-O-α-L-鼠李吡喃糖基(1→2)〔α-L-鼠李吡喃糖基(1→4)〕-β-D-葡萄吡喃糖甙(B);孕甾-5,16-二烯-3β-醇-20-酮,3β-O-α-L-鼠李吡喃糖基(1→2)〔α-L-鼠李吡喃糖基(1→4)-α-L-鼠李吡喃糖基(1→4)〕-β-D-葡萄吡喃糖甙(C)。甙A、B和C在滇重楼根中尚未发现,甙C系首次从重楼属植物中获得,而甙A具有止血的活性。     

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)。     

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)。     

半卧狗娃花中的黄酮类化合物

从半卧狗娃花(Heteropappus semiprost Griers)全草的乙醇提取物中分离并鉴定了7个黄酮类化合物,通过波谱分析及化学方法鉴定其结构为:3′,4′,5,7-四羟基黄酮(1),3′-甲氧基槲皮素(2),槲皮素-3-O-α-L-吡喃鼠李糖甙(3),槲皮素-3-O-β-D-吡喃半乳糖甙(4),异鼠李亭-3-O-β-D-吡喃半乳糖甙(5),槲皮素-3-O-α-L-吡喃鼠李糖(1→6)-β-D-吡喃葡萄糖甙(6),异鼠李亭-3-O-α-L-吡喃鼠李糖(1→6)-β-D-吡喃葡萄糖甙(7),其中化合物1~5为首次从本属植物中分离得到。     

滇产植物皂素成分的研究——Ⅵ.滇重楼皂甙(2)

从滇重楼干根粉中分离出三个甾体皂甙,鉴定为薯芋皂甙元-3-O-α-L-鼠李吡喃糖(1→2)-β-D-葡萄吡喃糖甙V,偏诺皂甙元-3-O-α-L-鼠李吡喃糖(1→2)-β-D-葡萄吡喃糖甙Ⅵ,偏诺皂甙元-3-O-α-L-鼠李吡哺糖(1→4)-α-L-鼠李吡喃糖(1→4)-〔α-L-鼠李吡喃糖(1→2)〕-β-D-葡萄吡喃糖甙Ⅶ.皂甙Ⅵ和Ⅶ已显示出有趣的生理活性。     

五指莲重楼的甾体皂甙(2)

从五指莲重楼根中(Paris axialis)分离鉴定了七个甾体皂甙,其中有一新甙Ⅶ,经MS、~1H NMR、~(13)C NMR和化学降解方法证明其化学结构为:24α-羟基偏诺皂甙元-3-O-α-L-鼠李吡喃糖基1→2[α-L-阿拉伯呋喃糖基1→4]-β-D-葡萄吡喃糖甙。     

小花草玉梅化学成分研究

目的:研究银莲花属植物小花草玉梅的化学成分。方法:采用硅胶柱色谱,凝胶柱色谱,反相柱色谱并结合制备高效液相色谱等技术分离纯化单体化合物,并根据理化性质及光谱数据鉴定结构。结果:分离并鉴定了4个化合物,分别是常春藤皂苷元-28-O-β-D-吡喃葡萄糖酯苷(1)、3-O-β-D-吡喃葡萄糖-(1→2)-α-L-吡喃阿拉伯糖-齐墩果酸皂苷元-28-O-α-L-吡喃鼠李糖-(1→4)-β-D-吡喃葡萄糖-(1→6)-β-D-吡喃葡萄糖酯苷(2)、3-O-β-D-吡喃葡萄糖-(1→2)-α-L-吡喃阿拉伯糖-常春藤皂苷元-28-O-α-L-吡喃鼠李糖-(1→4)-β-D-吡喃葡萄糖-(1→6)-β-D-吡喃葡萄糖酯苷(3)和3-O-β-D-吡喃核糖-(1→3)-α-L-吡喃鼠李糖-(1→2)-α-L-吡喃阿拉伯糖-常春藤皂苷元-28-O-α-L-吡喃鼠李糖-(1→4)-β-D-吡喃葡萄糖-(1→6)-β-D-吡喃葡萄糖酯苷(4)。结论:化合物1为首次从银莲花属植物中分离得到,2-4为首次从小花草玉梅中分离得到。     

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.