雪茶化学成分研究

由管枝衣科地茶属植物雪茶（Thamnolia vermicularis)丙酮提取物中分离得到10个成分,通过波谱分析及与已知品对照等方法,最终确定其中的9个化合物分别为:Thamnolin(1),鳞片衣酸（2）,坝巴酸（3）,羊角衣酸（4）,3β－羟基－5α,8α－桥二氧麦角甾－6,22－二烯（5）,3β－羟基－5α,8α－桥二氧麦角甾－6,9,22－三烯（6）,麦角甾烷－7,22－二烯－3－醇（7）,麦角甾烷－5,8,22－三烯－3－醇（8）,亚油酸(9)。其中,化合物1为新化合物,化合物3和6－9系首次由该种植物中分离得到。研究结果初步明确了云南中甸地区产雪茶为主要含有坝巴酸（3）和羊角衣酸（4）等酚性成分,而非主含地茶酸等酚性成分的植物品种类型,这为合理开发利用当地植物资源提供了科学依据。     

蒙椴树皮化学成分的研究

为研究蒙椴（Tilia mongolica Maxim.）树皮的化学成分,通过溶剂萃取、硅胶柱色谱、重结晶分离纯化,从蒙椴树皮中分离得到7个化合物,根据其红外光谱、质谱和核磁共振谱数据鉴定为β-香树脂醇乙酸酯（1）,计曼尼醇乙酸酯（2）,羽扇豆醇（3）,二十四碳酸（4）,三棕榈酸甘油酯（5）,β-谷甾醇（6）,胡萝卜苷（7）。其中化合物1-5、7均为首次从椴树属植物中分离得到,化合物6为首次从该植物中分离得到。     

紫花列当水溶性成分的研究

采用大孔树脂、SephadexLH-20等色谱方法,从列当科列当属植物紫花列当Orobanche coerulescens中分离得到六个水溶性成分,通过波谱技术及理化手段分别鉴定为类叶升麻苷（1）、异类叶升麻苷（2）、crenatoside（3）、cistanoside F（4）、sinapoyl-4—O-β-D-glucoside（5）、腺苷（6）。其中化合物5和6为首次从该属植物中分离得到。     

白花蛇舌草化学成分的研究

采用聚酰胺、Sepphadex LH-20、硅胶等多种色谱柱对白花蛇舌草的化学成分进行分离纯化,并根据化合物的理化性质和光谱数据鉴定其结构为：去乙酰车叶草甙（1）、车叶草甙（2）、鸡屎藤甙甲酯（3）、车叶草酸（4）、去乙酰车叶草酸甲酯（5）和dapbylloside（6）。其中化合物6为首次从该属植物中分离得到,化合物1,5、6为首次从该种植物中得到。     

灯盏花中的糖苷

从灯盏花（Erigeron breviscapus (Vant.) Hand.-Mazz.) 全株的乙醇提取物的正丁醇部分分得10个化合物,通过波谱方法鉴定为erigeside I(1)、γ－吡喃酮－3－O－β－D－[6′－（4″－羟基－3″,5″－二甲氧基苯甲酰）-]-吡喃葡萄糖苷（erigeside D,2)、erigeside A(3)、erigeside B(4)、erigeside Ⅱ(5)、7-O-β-D-吡喃葡萄糖－6－甲氧基香豆素（6）、icariside B2(7)、blumenol C葡萄糖苷（8）、（＋）－丁香树酯醇O－β－D－吡喃葡萄糖苷（9）和野黄芩苷甲酯（10）。用X射线单晶衍射方法确定了化合物7的绝对构型。2是一个新化合物,7、8和9首次从该属植物分离得到,6首次从该种植物分离得到。     

崖椒茎的化学成分

从崖椒（Zanthoxglum schinifolutm Sieb.et Zucc.)茎的石油醚、二氯甲烷提取物中分离得到8个化合物。经物理常数测定及光谱（UV,IR,MS,NMR)分析鉴定其为（1）白鲜碱（dictamning),（2）茵芋碱（skimmianine),(3)滨蒿内酯（scoparone),(4)崖椒内酯（schinifolin),(5)莨菪亭（scopoletin),（6）7-羟基-8-甲氧基香豆素（7-hydroxy-8-methoxycoumarin),（7）N-甲基弗林辛（N-methylflindersine),（8）β-谷甾醇（β-sitosterol),其中化合物（5）、（6）和（7）为首次从该植物中分离。     

遍地金的化学成分研究Ⅱ

从遍地金(Hypericum wightianum Wall．ex Wight et Am．)乙醇提取物中分离得到3个化合物,经波谱分析鉴定为6-deoxyisojacareubin(1),6-异戊烯基槲皮素-3-甲醚(2)和香草酸(3)。3个化合物均为首次从该植物中分离得到。     

蓝桉果实中的脂溶性成分

从蓝桉(Eucalyptus globulusLabill.)果实乙醇提取物的石油醚部位分离鉴定出6个化合物,通过理化和波谱分析结构鉴定为:5-羟基-4′,7-二甲氧基-6-甲基黄酮(1)、blumenol A(2)、蓝桉醇(3)、绿花白千层醇(4)、β-谷甾醇(5)、二十二烷酸(6),其中化合物1~4和化合物6系首次从该植物中分离得到,化合物1和2首次从桉属植物中分离得到.     

无梗五加根中苯丙素类化合物的研究

从无梗五加(Acanthoparax sessiliflorus( Rupr.et Maxim.)Seem.)根70％乙醇提取物的乙酸乙酯层中提取分离得到8个苯丙素类化合物.经理化和波谱分析鉴定为(+)-表芝麻脂素(1)、(-)-芝麻脂素(2)、赛菊芋黄素(3)、洒维宁(4)、咖啡酸甲酯(5)、对羟基桂皮酸(6)、(-)-丁香脂素(7)、(+)-松脂索(8).化合物8是首次从五加科植物中分离得到,化合物1和5是首次从五加属植物中分离得到,化合物3、6和7是首次从该植物中分离得到.     

北美盐角草(Salicornia bigelovii Torr.)化学成分的研究(英文)

从北美盐角草中分离得到6个化合物,运用波谱手段分别鉴定为东莨菪内酯(1),杜松脑(2),金丝桃苷(3),槲皮素(4),异鼠李素-3-O-β-D-葡萄糖苷(5)和β-谷甾醇(6)。其中,化合物1和2为该属植物中首次分离得到,化合物4和6为首次从该种植物中得到。     

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.     

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.     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.     

Composition and diversity of bird communities in Swedish farmland–forest mosaic landscapes

CapsuleThe amount of forest (at local and landscape scales) and occurrence of residual habitats at the local scale are shown to be the major factors influencing bird community composition in farmland–forest landscapes in central Sweden.

Aims To investigate the importance of local habitat and landscape structure for breeding birds in farmland–forest landscapes in central Sweden.

Methods Breeding birds were censused at 292 points. A detailed habitat mapping was made within 300 m of the points. Within a 300–600 m radius only two major habitats (forests and arable fields) were identified.

Results Cluster analyses of bird communities identified three site types that also differed in habitat composition: (i) partially forested sites in forested landscapes; (ii) heterogeneous sites with residual habitats in mosaic landscapes; and (iii) field-dominated farmland sites in open landscapes. A total of 19 of 25 farmland bird species (restricted to farmland or using both farmland and forest) had the highest abundance in farmland sites with mosaics of forest and farmland, while only six farmland species had the highest abundance in field-dominated sites. The bird community changed from being dominated by farmland species to being dominated by forest species (common in forest landscapes without farmland) at small proportions (10–20%) of forest at the local scale. A major difference in habitat composition between heterogeneous and field-dominated sites was the occurrence of different residual habitats (e.g. shrubby areas and seminatural grasslands). These habitats seemed to influence bird community composition more than land-use, despite covering <10% of the area. Seminatural grasslands were important for bird community composition and species-richness, but grazing seemed to be less important. Among different land-use types, cereal crops were the least preferred fields. Set-asides with tall vegetation and short rotation coppices were positively associated with species-richness of farmland birds.

Conclusion In general, the composition of the landscape was important for bird community composition, although amount and distribution of forests, occurrence of residual habitats and land-use of fields at the local scale had the strongest influence on bird community composition. The possible implications of these patterns for managing farmland–forest landscapes are discussed.     

Chemical constituents from the fruits of Rhus typhina L. and their chemotaxonomic significance

This work describes the isolation and characterization of twenty-nine compounds from the fruits of Rhus typhina L., including eleven flavonoids (1–11), eleven phenols (12–22), two pentacyclic triterpenes (23–24), two organic acids (25–26), one lumichrome (27), one courmarin (28) and one pyrimidine (29) on the basis of their spectroscopic data. Compounds apigenin (1), daidzein (4), orobol (5), 3′, 5, 5′, 7-tetrahydroxyflavanone (6), naringenin (7), butein (8), (-)-catechin (9), quercetin-3-O-α-L-(3″-O-galloyl)-rhamnoside (11), 2-hydroxybenzoic acid (13), 4-hydroxybenzaldehyde (14), vanillin (15), methyl 3,4-dihydroxybenzoate (16), 3,5-dihydroxybenzamide (18), tyrosol (19), caffeic acid (20), 3-(2,4,6-trihydroxyphenyl)-1-(4-hydroxyphenyl)-propan-1-one (21), phlorizin (22), friedelin (23), oleanolic acid (24), 4,4-dimethyl-heptanedioic acid (25), anthranilic acid (26), lumichrome (27), scoparone (28) and uracil (29) have not been recorded before in this plant. This is the first report on the occurrence of compounds 4–7, 9, 11, 13–14, 16, 18–21, 25–29 from the genus Rhus. Moreover, the chemotaxonomic significance of these isolated compounds was also summarized.