检索结果-南通市图书馆

A Novel Triterpenic Acid from Gymnema sylvestre

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2005年第2期16卷 223-224页

作者： ShuLinPENG XuMinZHU MingKuiWANG LiShengDING chengduinstituteofbiology ChineseAcademyofScinecesChengdu610041

A novel oleanane-type triterpenic acid was isolated from the leaves of Gymnema sylvestre(Asclepiadaceae). The structure was characterized as 3β, 16β, 22β, 28-tetrahydroxy- olean-12-en-30-oic acid on the basis of sp... 详细信息

关键词： Gymnema sylvestre Asclepiadaceae triterpenic acid.

Soil N Pools and Transformation Rates Under Different Land Uses in a Subalpine Forest-Grassland Ecotone

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2005年第1期15卷 52-58页

作者： SUNGeng WUNing LUOPeng chengduinstituteofbiology ChineseAcademyofSciencesChengdu610041China

Soil nitrogen pools (NP), denitrification (DN), gross nitrification (GN), N2O and CO2 flux rates with their responses to temperature increases were determined under five different land uses and managements in a subalpine forest-grassland ecotone of the eastern Tibetan Plateau. Land uses consisted of 1) sparse woodland, 2) shrub-land, 3) natural pasture, 4)fenced pasture, and 5) tilled pasture mimicking a gradient degenerating ecosystem under grazing impacts. The NO3--N content was higher than the NH4+-N content. Comparing tilled pasture with fenced pasture showed that higher intensive management (tillage) led to a significant decrease of soil organic matter (SOM) (P ＜ 0.05) in the soils, which was in contrast to the significant increases (P ＜0.05) of DN, GN, N2O and CO2 flux rates. GN (excluding tilled pasture) and CO2 flux rates increased with a temperature rise, but DN and N2O flux rates normally reached their maximum values at 12-14 ℃ with tilled pasture (the highest management intensity) being very sensitive to temperature increases. There was a difference between net nitrification and GN, with GN being a betterindicator of soil nitrification.

关键词： denitrification gross nitrification land use subalpine forest-grassland ecotone Tibetan Plateau

Glycosides from Roots of Cyathula officinalis Kuan

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Plant Biology 2005年第3期47卷 368-374页

作者： RongZHOU Bo-GangLI Guo-LinZHANG chengduinstituteofbiology theChineseAcademyofSciencesChengdu610041China

To search for new and bioactive compounds from traditional Chinese medicines, a new glycoside,3-O-[α-L-rhamnopyranosyl-(l-→3)-(n-butyl-β-D-glucopyranosiduronate)]-28-O-β-D-glucopyranosyl oleanolic acid (1), was isolated from the roots of Cyathula officinalis Kuan, along with 3-O-(methyl-β-D-glucopyranosiduronate)-28-O-β-D-glucopyranosyl oleanolic acid (2), 3-O-β-D-glucopyranosyl oleanolic acid (3), 3-O-β-D-glucuronopyranosyl oleanolic acid (4), 3-O-[α-L-rhamnopyranosyl-(l→3)-(β-D-glucuronopyranosyl)] oleanolic acid (5), 3-O-(β-D-glucuronopyranosyl)-28-O-β-D-glucopyranosyl oleanolic acid (6), 28-O-β-D-glucuronopyranosyl-(1→4)-β-D-glucopyranosyl hederagenin (7), 3-O-[α-L-rhamnopyranosyl-(1→3)-β-D-glucuronopyranosyl]-28-O-β-D-glucopyranosyl oleanolic acid (8), and 3-O-[β-D-glucopyranosyl-(1→2)-α-L-rhamnopyranosyl-(1→3)-β-D-glucuronopyranosyl]-28-O-β-D-glucopyranosyl oleanolic acid (9). The structures of these compounds were determined based on spectral and chemical evidence. The 50 per cent growth-inhibiting (GI50) of compounds 1 and 5 against MDA-MB-231(a human breast cancer cell line) was 3.44 × 10-4 and 4.66 × 10-4 mol/L, respectively.

关键词： Cyathula officinalis Kuan cytotoxic activity glycoside oleanolic acid

Chemical Constituents from the Seeds of Ziziphusjujuba var. spinosa （Bunge） Hu

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Integrative Plant Biology 2005年第4期47卷 494-498页

作者： Li-MeiLI XunLIAO Shu-LinPENG Li-ShengDING chengduinstituteofbiology theChineseAcademyofSciencesChengdu610041China

To search for new and bioactive minor components from traditional Chinese medicines, a new compound, named jujuphenoside (1), was isolated from the seeds of Ziziphusjujuba var. spinosa (Bunge)Hu. The structure of jujuphenoside was elucidated by spectral and chemical methods, particularly twodimensional nuclear magnetic resonance analysis. Together with the new compound, 22 known compounds were also isolated and identified from the seeds of Z. jujuba var. spinosa, among which, epiceanothic acid (2) was first obtained from natural resources, whereas compounds 7-16 were first obtained from this plant.

关键词： chemical constituent jujuphenoside phenyl glycoside Rhammaceae Ziziphus jujuba var.spinosa(Bunge)Hu.

Two New Triterpenoids from the Roots of Sanguisorba officinalis L.

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Integrative Plant Biology 2005年第2期47卷 251-256页

作者： FanZHANG Tie-JunFU Shu-LinPENG Zhong-RongLIU Li-ShengDING NationalEngineeringResearchCenterforNaturalMedicines ChengduInstituteofBiologytheChineseAcademyofSciencesChengdu610041China

Two new triterpenoids, octanordammar- 1,11,13(17)-trien- 17-ol-3,16-dione (1) and lup- 12-en- 15α,19β-diol-3,11-dioxo-28-oic acid (4), as well as 13 known compounds were isolated from the roots of Sanguisorba offici... 详细信息

关键词： lup-12-en-150,193-diol-3,11-dioxo-28-oicacid octanordammar-1,11,13(17)-trien-17-0l-3,16-dione Sanguisorba officinalis L. triterpenoid

Chemical Constituents of Acanthochlamys bracteata

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2005年第7期23卷 933-936页

作者：李帮经高宝莼彭树林廖循丁立生 chengduinstituteofbiology ChineseAcademyofSciencesChengduSichuan610041China

A novel nortriterpene, acanthochlamic acid (6), along with 18 known compounds has been isolated from the whole plants of Acanthochlamys bracteata P. C. Kao, a single species in family Acanthochlamydaceae which is endemic to the southwest of China. The structure of the novel nortriterpene was elucidated as 3,4-seco-3-nor-lup-4(23),20(29)-dien-2,28-dioic acid by spectroscopic techniques including 1D and 2D NMR spectroscopy and confirmed by X-ray crystallography.

关键词： Acanthochlamys bracteata Acanthochlamydaceae chemical constituent acanthochlamic acid

Synthesis of 7a-Aza-benzo[fg]naphthacen-7-one

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2004年第3期15卷 269-272页

作者： ChengGangZHANG BoGangLI XiangGeZHOU GuoLinZHANG ChengduInstituteofOrganicChemistry ChineseAcademyofSciencesChengdu610041 chengduinstituteofbiology ChineseAcademyofSciencesChengdu610041

2, 3, 11, 12-Tetramethoxy-3b, 4, 5, 6-tetrahydro-8H-7a-aza-benzo[fg]naphthacen-7-one 7 was synthesized via N-acyliminium ion cyclization of 6-hydroxy-1-(2, 3, 6, 7-tetramethoxy- phenanthren-9-yl-methyl)-piperidin-2-one 6 catalyzed by BF3OEt2. The stereostructure of the intermediate, 1-(2, 3, 6, 7-tetramethoxy-phenanthren-9-yl-methyl)-piperidine-2, 6-dione 5, was confirmed by X-ray crystallographic analysis. Compound 7 showed no cytotoxicity.

关键词： N-Acyliminium ion cyclization cytotoxicity.

Soil Enzyme Activity Changes in Different-Aged Spruce Forests of the Eastern Qinghai-Tibetan Plateau

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2004年第3期14卷 305-312页

作者： ZHANGYong-Mei ZHOUGuo-Yi WUNing BAOWei-Kai SouthChinaInstituteofBotany ChineseAcademyofSciencesGuangzhou510650（China） chengduinstituteofbiology ChineseAcademyofSciencesChengdu610041（China）

Activities of selected soil enzymes (invertase, acid phosphatase, proteinase,catalase, peroxidase and polyphenoloxi-dase) were determined under different spruce forests withrestoration histories of 5, 13, 18, 23, 27 years and an old growth forest over 400 years old in theeastern Qinghai-Tibetan Plateau, China, and their possible use as indicators of ecosystems healthwere analyzed. Plots 10 X 10 m with 4 replications were established to investigate three hypotheses:soil enzyme activities a) would increase with the restoration process; b) would be greater insurface soils than at lower depths; and c) would be correlated to selected physicochemicalproperties. Results showed that as the forests developed after restoration, invertase and peroxidaseactivities usually increased up to the 23 year point. Also soil enzyme activities were associatedwith surface soils and decreased with depths, suggesting that in earlier restoration stages surfaceaddition of organic fertilizer to soils might be more effective than additions at depth. In the 0-20cm soil, there were significant correlations (P < 0.01 or < 0.05) between some soil enzymeactivities and some selected chemical properties. Therefore, temporal changes in enzyme activitiesshould be included as an indicator when evaluating sustainable forest management practices.

关键词： acid phosphatase catalase invertase peroxidase spruce forest (picea spp.)

Effects of Elevated Solar UV-B Radiation from Ozone Depletion on Terrestrial Ecosystems

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2004年第3期1卷 276-288页

作者： LIUQing TerryV.Callaghan ZUOYuanyuan chengduinstituteofbiology ChineseAcademyofSciencesChengdu610041China chengduinstituteofbiology ChineseAcademyofSciencesChengdu610041China／／SheffieldCentreforArcticEcologyDepartmentofAnimalandPlantSciencesUniversityofSheffieldSheffieldS105BRUK

In the last three decades much researchhas been carried out to investigate the biologicaleffects of a thinning stratospheric ozone layeraccompanied by an enhanced level of solarultraviolet-B radiation at the Earth’s *** UV-B radiation affects ecosystems in manyways directly and indirectly. The responses can bebiochemical, physiological, morphological oranatomical, and the direction of the response can varybetween different species, communities andecosystems. In this paper we firstly introduce generalconcepts, and methods for measuring the ecologicaleffects of UV-B radiation. Secondly, we provide anoverview interpretation of the effects of enhancedUV-B on terrestrial ecosystems from recent *** studies include effects of UV-B on growth andreproduction, composition of communities,competitive balance, decomposition of litter, andinteractions with other factors etc. Finally, werecommend future research directions to identify theeffects of elevated UV-B radiation on ecosystems inChina.

关键词： Elevated UV-B effects ecosystem community composition decomposition