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31.
Biomarkers in a peat deposit in Northern Spain (Huelga de Bayas,Asturias) as proxy for climate variation 总被引:1,自引:0,他引:1
V. López-Días Á.G. Borrego C.G. Blanco M. Arboleya J.A. López-Sáez L. López-Merino 《Journal of chromatography. A》2010,1217(21):3538-3546
Peatlands are peculiar ecosystems in which well-adapted communities grow and develop, recording the variation in climate and hydrological conditions inland. In addition necromass is well preserved and therefore peatlands can be used as palaeo-archives for environmental variation. In this work a peat core of depth 60 cm dated at the bottom of the peat deposit as ca. 250 cal AD from Huelga de Bayas (Asturias, Northern Spain) was studied to a resolution of 2–4 cm to investigate the evolution of the environmental conditions in the area. Samples were extracted with a dichloromethane/methanol ratio of 3:1 and studied by means of gas chromatography (GC) and mass spectrometry (GC–MS) in order to identify possible biomarkers of climatic variation during the period of peat formation. Lipid biomarker study allows the identification of periods in which Sphagnum or higher plants preferentially contributed to the peat profile. The absolute dating of the profile combined with the n-alkane record displayed five episodes of wetter conditions around ca. 250 cal AD (Roman Warm Period), 1080 and 1270 cal AD (Medieval Warm Period), 1460 cal AD (Little Ice Age) and 1920 cal AD (Recent warming), which are consistent with climate evolution in the region. Pentacyclic triterpenoids with hopane skeleton derived from microorganisms and with oleanane skeleton derived from higher plants were identified. The presence of their ketone and acetyl-derivatives, along with the presence of unstable hopane configurations indicates a low maturity of the peat profile. A tendency for the functionalised triterpenoids to decrease with depth was observed in the profile. 相似文献
32.
Serge Michalet Laëtitia Payen‐Fattaccioli Chantal Beney Pascale Cégiéla Christine Bayet Gilbert Cartier Diderot Noungoué‐Tchamo Etienne Tsamo Anne‐Marie Mariotte Marie‐Geneviève Dijoux‐Franca 《Helvetica chimica acta》2008,91(6):1106-1117
Phytochemical investigation of barks of Christiana africana led to the identification of cyclopeptide alkaloids, flavonoids, coumarinolignans, iridoids, sesquiterpenoids, and triterpenes. This plant was classified so far in the Tiliaceae family. This study was started while the genomic study of numerous specimens was described in order to establish new criteria for Malvales botanical classification. In the present work, twenty components were identified, belonging to the three major classes of secondary metabolites: alkaloids, phenols, and terpenes. In the first class, cyclopeptides are well‐known compounds in Rhamnaceae and Sterculiaceae. Their presence in Malvaceae (in APG2 sensus) suggests a possible chemical link between the ex‐Tiliaceae and the Malvaceae. 相似文献
33.
Elvira M. S. M. Gaspar Higuinaldo J. Chaves das Neves Joo P. Noronha 《Journal of separation science》1997,20(8):417-420
An extract fraction fruits of Arbutus unedo, L., was cleaned-up by column chromatography and shown by NMR to be a mixture of isomers that resists further attempts at separation by conventional chromatographic methods. High resolution gas chromatography-mass spectrometry (HRGC-MS) confirms the presence of triter-penoid isomers but does not allow separation of all the components. This can be improved by trimethylsilylation but the absence of molecular ions and the complex spectra are difficult to interpret. Complete separation can be achieved by high pressure liquid chro-matography (HPLC) coupled to a mass spectrometer by means of a particle beam interface (HPLC-PBMS). Four triterpene com-pounds are identified through analysis of the corresponding mass spectra: α-amyrin, β-amyrin, and Lupeol, have for the first time been identified in Arbutus unedo, L. Fruits. A new natural triterpene tentatively identified as olean-12-en-3β, 23-diol is described for the first time. 相似文献
34.
New biologically active linear triterpenes from the bark of three new-caledonian Cupaniopsis species
In the course of automated screening for small-molecule agonists to peroxisome proliferator-activated receptor-γ (PPAR-γ), 10 new linear triterpenes 1-10 have been isolated from the bark of three neocaledonian Cupaniopsis species, SAPINDACEAE. The structures were elucidated by extensive mono- and bi-dimensional spectroscopy and mass spectrometry. 相似文献
35.
Jing‐Hua Yang Yun‐Song Wang Rong Huang Shi‐De Luo Hong‐Bin Zhang Liang Li 《Helvetica chimica acta》2006,89(11):2830-2835
Two new polyoxygenated triterpenoids, stachlic acid A (= (2α,3β)‐2,3,23,29‐tetrahydroxyolean‐12‐en‐28‐oic acid; 1 ) and stachlic acid B (= (2α,3α)‐2,29‐dihydroxy‐3,23‐[(1,1‐dimethylmethylene)dioxy]olean‐12‐ene‐28‐oic acid; 2 ), were isolated from Stachyurus himalaicus var. himalaicus. Their structures were established by means of extensive spectroscopic studies and chemical evidence. The purified product 1 was found to have moderate in vitro cytotoxic activity against human Hela cells. 相似文献
36.
Sheng‐Xiang Yang Jin‐Ming Gao Jian‐Chun Qin Lin Zhou Ming‐Hua Chiu Lei Wang 《Helvetica chimica acta》2007,90(8):1477-1481
A new triterpene, (3β,12β)‐taraxast‐20(30)‐ene‐3,12‐diol (=(3β,12β,18α,19α)‐urs‐20(30)‐ene‐3,12‐diol; 1 ), together with the known compounds ursolic acid, α‐amyrin, β‐amyrin, (2α,3β)‐2,3‐dihydroxyursa‐5,12‐dien‐28‐oic acid, (2α,3β)‐2,3,23‐trihydroxyurs‐12‐en‐28‐oic acid, (2S,3S,4R,8Z)‐1‐O‐(β‐D ‐glucopyranosyl)‐2‐{[(2R)‐2‐hydroxydocosanoyl]amino}octadec‐8‐ene‐1,3,4‐triol, and (2S,3S,4R,8Z)‐1‐O‐(β‐D ‐glucopyranosyl)‐2‐[(palmitoyl)amino]octadec‐8‐ene‐1,3,4‐triol, and quercetin 3‐(β‐D ‐glucopyranoside) were isolated from the leaves of Craibiodendron yunnanense. Their structures were established on the basis of spectral evidence. The last four compounds were identified for the first time in this plant. 相似文献
37.
Xiao‐Jie Gu You‐Bin Li Ping Li Shi‐Hui Qian Jian‐Feng Zhang 《Helvetica chimica acta》2007,90(1):72-78
Three new oleanane‐skeleton triterpenoid saponins, 3β,4β,16α‐17‐carboxy‐16,24‐dihydroxy‐28‐norolean‐12‐en‐3‐yl 4‐O‐β‐D ‐xylopyranosyl‐β‐D ‐glucopyranosiduronic acid ( 1 ), (3β,4β,16α)‐17‐carboxy‐16,24‐dihydroxy‐28‐norolean‐12‐en‐3‐yl β‐D ‐glucopyranosiduronic acid methyl ester ( 2 ), and (3β,4β)‐24‐hydroxy‐16‐oxo‐28‐norolean‐12‐en‐3‐yl 4‐O‐β‐D ‐xylopyranosyl‐β‐D ‐glucopyranosiduronic acid ( 3 ), together with eight known constituents, i.e., the oleanane‐type triterpenoids 4 – 6 , and the ursane‐type triterpenoids 7 – 11 , were isolated from the spikes of Prunella vulgaris. The new structures were established by means of detailed spectroscopic analysis (IR, HR‐ESI‐MS, 1D‐ and 2D‐NMR experiments). Compounds 1 – 3 were tested for their inhibition activity against the growth of tumor cell lines; only compound 3 displayed marginal inhibition activity. 相似文献
38.
From the root bark ofGardenia imperialis two triterpenoids were isolated and identified as pulcherrol (= 3-epi--amyrin) and -amyrin acetate.
Triterpenoide vonGardenia imperialis (Kurze Mitteilung)
Zusammenfassung Aus der Rinde der Wurzeln vonGardenia imperialis wurden zwei Triterpene isoliert, die als Pulcherrol (= 3-epi--Amyrin) und -Amyrinacetat identifiziert wurden.相似文献
39.
Lin Shi De‐Hong Tan Yun‐En Liu Ming‐Xiao Hou Yu‐Qing Zhao 《Helvetica chimica acta》2014,97(10):1333-1339
Two new dammarane‐type triterpenoid saponins were isolated from the EtOH extract of Gynostemma pentaphyllum (Thunb .) Makino . Their structural elucidations were accomplished mainly on the basis of the interpretation of spectroscopic data, such as IR, NMR, and HR‐TOF‐MS. Their liver fibrosis inhibitory activities were evaluated against hepatic stellate cells using 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl‐2H‐tetrazolium bromide (MTT) assay. Thus, G. pentaphyllum can be used as ingredient for ancillary drugs or functional food. 相似文献
40.
Shou‐Li Wang Zhong Chen Xiao‐Jing Tong Yan‐Li Liu Xia Li Qiong‐Ming Xu Xiao‐Ran Li Shi‐Lin Yang 《Helvetica chimica acta》2013,96(6):1126-1133
Three new triterpenoids, 21β,22α‐diangeloyloxy‐3β,15α,16α,28‐tetrahydroxyolean‐12‐en‐23‐al ( 1 ), 21β‐angeloyloxy‐3β,15α,16α,28‐tetrahydroxy‐22α‐(2‐methylbutanoyloxy)olean‐12‐en‐23‐al ( 2 ), and 21β‐angeloyloxy‐3β,16α,28‐trihydroxy‐22α‐(2‐methylbutanoyloxy)olean‐12‐en‐23‐al ( 3 ), along with six known triterpenoids, were isolated from the roots of Camellia oleifera C.Abel . The structures of compounds 1 – 3 were elucidated on the basis of spectroscopic analyses. Moreover, all compounds isolated were evaluated for their cytotoxic activities by MTT (=3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl‐2H‐tetrazolium bromide) assay. 相似文献