棉毛橐吾根茎中化学成分研究

采用硅胶、Sephadex LH-20凝胶、Toyopearl HW-40凝胶及Diaion HP-20树脂等色谱方法从云南丽江棉毛橐吾中分离得到化合物18个,通过理化手段及波谱技术分别鉴定为:呋喃艾里莫芬-14β,6α-内酯(1)、β-谷甾醇(2)、惕格酸(3)、棕榈酸(4)、十九烷酸甲酯(5)、艾里莫芬-7(11)-烯-12,8α(14β,6α)-二内酯(6)、8β-甲氧基艾里莫芬-7(11)-烯-12,8α(14β,6α)-二内酯(7)、1-O-十六烷酰基甘油酯(8)、8β-羟基艾里莫芬-7(11)-烯-12,8α(14β,6α)-二内酯(9)、对羟基桂皮酸甲酯(10)、对羟基苯乙酮(11)、伞形花内酯(12)、3,4-二羟基苯乙酮(13)、胡萝卜苷(14)、1,5-二咖啡酰奎宁酸(15)、对羟基桂皮酸(16)、咖啡酸(17)及七叶内酯(18),其中化合物4~5,8,10,13,15及17,18为首次从该植物中分离得到。     

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。     

三花枪刀药中萜类和甾体成分研究

采用正相硅胶和Sephadex LH-20等柱层析及半制备HPLC色谱法,从三花枪刀药的95%乙醇提取物中分离到15个化合物,运用现代波谱技术分别鉴定为6-羟基-9,13环大柱烷-4,9(13)-二烯-3-酮(1)、3β-羟基-β-紫罗酮(2)、3α-羟基-大柱烷-4,7E二烯-9-酮(3)、3α-羟基-5α,6α-环氧-7E-大柱烷-7-烯-9-酮(4)、黑麦草内酯(5)、pisiferadinol(6)、24-methylenecycloartanol(7)、α-香树脂醇(8)、3β-羟基-乌苏烷-11-烯-28,13β-内酯(9)、羽扇豆醇(10)、achilleol A(11)、6β-甲氧基麦角甾烷-7,22E-二烯-3β,5α-二醇(12)、6β-乙氧基麦角甾烷-7,22E-二烯-3β,5α-二醇(13)、豆甾烷-4-烯-3,6-二酮(14)、豆甾烷-4,22E-二烯-3,6-二酮(15)。化合物1为新天然产物,化合物2~15为首次从该植物中分离得到。化合物6、12、15对人乳腺癌MDA-MB-468、人胃癌AGS、人结肠癌HCT116、人宫颈癌Hela和人乳腺癌MDA-MB-231肿瘤细胞株具有显著的细胞毒活性。     

鲍氏层孔菌子实体的化学成分研究

采用硅胶和Sephadex LH20柱层析方法,从鲍氏层孔菌子实体提取物中分离得到8个化合物。运用NMR和MS等波谱法分析和鉴定为7(8),22(23)-二烯-3-酮-麦角甾烷、4,6,8(14),22(23)-四烯-3-酮-麦角甾烷、麦角甾醇、过氧化麦角甾醇、三十烷酸对羟基苯乙酯、4-(3,4-二羟苯基)-3-丁烯-2-酮、hispolon、hispidin。     

中华小苦荬萜类化学成分的研究(英文)

从中华小苦荬全草的乙酸乙酯提取物中分离得到8个萜类化合物,通过波谱方法及文献对照分别鉴定为β-香树脂素(1),3β-羟基-20(30)-蒲公英甾烯(2),熊果-12-烯-3β-醇(3),羽扇豆醇(4),10-羟基艾里莫芬-7(11)-烯-12,8α-内酯(5),乌苏-12,20(30)-二烯-3β,28-二醇(6),3β,8α-二羟基-6β-当归酰基艾里莫芬-7(11)-烯-12,8β-内酯(7)和乌苏酸(8),化合物1～8均首次从该植物中分离得到。     

攀援孔药花化学成分研究

从攀援孔药花全草95%乙醇提取物中首次分离得到19个化合物,通过波谱数据或与已知物对照,它们分别鉴定为:(2S,3S,4R)-2-[(2R)-2-羟基-二十一酰胺基]-二十一烷-1,3,4-三醇(1)、(2S,3S,4R)-2-二十四酰胺基-十八烷-1,3,4-三醇(2)、胡萝卜甙(3)、β-谷甾醇(4)、(20S,22E,24R)-5α,8α-表二氧-麦角甾-6,22-二烯-3β-醇(5)、6β-羟基-豆甾-4-烯-3-酮(6)、十六烷酸-1-甘油酯(7)、桦木酸(8)、大黄素(9)、二十二烷酸-1-甘油酯(10)、对羟基苯甲醛(11)、十七烷酸-1-甘油酯(12)、金色酰胺醇乙酸酯(13)、十九烷酸-1-甘油酯(14)、棕榈酸(15)(、E)-p-香豆酸(16)、(22E,24S)-24-甲基-5α-胆甾-7,22-二烯-3β,5α,6β-三醇(17)、2-去氧-β-蜕皮激素(18)和auranamide(19)。     

蓝桉果实中的五环三萜化学成分

从蓝桉果实乙醇提取物的乙酸乙酯部位分离得到7个五环三萜化合物,经理化和波谱分析鉴定为3β-乙酰基-乌索-11,12-烯-28,13β内酯(1)、桦木酮酸(2)、白桦脂酸(3)、2α-羟基白桦脂酸(4)、2α,3β-二羟基乌苏-12-烯-28-酸(5)、熊果酸(6)、3β-羟基-乌索-11,12-烯-28,13β内酯(7),其中化合物1,4,5和7系首次从该植物中分离得到。     

西北蔷薇果实化学成分的研究

从西北蔷薇（Rosa davidii Crep.)果实中分得１１个化合物,经波谱方法鉴定为：２α,３β,１９β－三羟基－齐墩果烷－１２－烯－２８－酸（１）２α,３β－二羟基－乌苏烷－２８（１３）－内酯（２）、arjunic acid(3)、蔷薇酸（４）、２α,３β－二羟基乌苏酸（５）、齐墩果酸（６）、山奈素（６）、tiliroside(８）、槲皮素（９）、胡萝卜甙（１０）和β－谷甾醇（１１）。其中１和２为首次发现的新化合物。     

叉子圆柏中的抗肿瘤化学成分

从叉子圆柏(Sabina vulgaris Ant.)的树皮中分得12种成分,根据其理化性质、化学反应及光谱分析,其中11种成分鉴定为反式璎珞柏酸(Ⅰ),顺式璎珞柏酸(Ⅱ),山达海松酸(Ⅲ),异柏油酸(Ⅳ)、柳杉酚(Ⅴ)、12-羟基-6,7-断松香烷8,11,13三烯6,7二醛(Ⅵ),β-足叶草素 A 早醚(Ⅶ),佛手内酯(Ⅷ),β-谷甾醇(Ⅹ),二十四烷酸(Ⅺ)和蜡酸(Ⅻ),另一种是新的3,4苯并香豆素类化合物,命名为圆柏内酯(sabilactone,Ⅸ),Ⅳ-Ⅹ为首次从该植物中分得。生物试验表明Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅵ和Ⅶ具有细胞毒作用。     

臭灵丹中四个新的倍半萜酸

从云南省芒市产臭灵丹［Ｌａｇｇｅｒａｐｔｅｒｏｄｎｔａ（ＤＣ．）Ｂｅｎｔｈ］中,分离得以４个新的桉烷型倍半萜酸,结构鉴定为５,１２－二烯－桉烷－１３－酸（１）;１β－式－５,１２－二烯－桉烷－１３－酸（２）;３β－羟基－５,１２－二烯－桉烷－１３－酸（３）。     

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.