118 resultados para Pentacyclic triterpenoids


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The methanolic extract of the bark of the medicinal plant Qualea parviflora (Vochysiaceae) contains new nor-seco-triterpene and pentacyclic triterpenoids. They were separated in a preparative scale using droplet counter-current chromatography. The optimum solvent used was composed of a mixture of CHCl3/MeOH/H2O (43:37:20, v/v) in the descending mode and led to a successful separation of the new compound 28-nor-17, 22-seco-2 alpha, 3 beta, 19, 22, 23-pentahydroxy-Delta(12)-olecinane, besides the known triterpenoids bellericagenin B, bellericaside B and arjunglucoside I. Identification was performed by ESI-MS, H-1 NMR and C-13 NMR analyses.

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本论文由三章组成。第一、二章分别报道钩藤、蹄叶橐吾的化学成分研究工作。从两种药用植物中共分离和鉴定了37 个化合物,其中有1 组6 个新的骨架相似的鞘糖脂类同系物及5 个新的倍半萜类化合物。第三章概述了艾里莫芬烷内酯类化合物的研究进展。 第一章报道钩藤(Uncaria rhynchophylla)带钩茎枝乙醇提取物的化学成分。采用正、反相硅胶柱层析等分离方法,运用NMR、MS 等波谱技术共分离鉴定得到22 个化合物,分属于五环三萜类化合物、鞘糖脂类化合物等,其中有1 组6个新的鞘糖脂类化合物同系物,另外有7 个化合物首次从该植物中分离得到。 第二章报道蹄叶橐吾(Ligularia fischeri)根部乙醇提取物化学成分的分离纯化和结构鉴定。通过正、反相硅胶柱层析等分离纯化和MS、NMR 等波谱解析,共分离鉴定得到18 个化合物,其中5 个是新化合物。它们的结构分别确定为3β-acetyl-6β, 8α, 10β-trihydroxyeremophila-7(11)-en-8, 12-olide (23), 3β-acetyl-8β,10β-dihydroxy-6β-(2-methylbutyryloxy)-eremophilenolide (24), 3β-acetyl-6β, 10β-dihydroxyeremophila-7(11), 8(9)-dien-8, 12-olide (25), 3β-acetyl-6β, 10β-dihydroxyeremophila- 7(11), 8(9)-dien-8, 12-olide (26), (3aR, 4R, 5S, 7aS)-2-acetyl-7ahydroxy-3a, 4, 5, 6, 7, 7a-hexahydro-1H-inden-5-yl acetate (27)。这5 个化合物经体外生物活性测试,结果表明化合物23 具有抑制酪氨酸磷酸酯酶的活性, 其IC50 值为1.30 μg/ml。 第三章概述了近二十年来艾里莫芬烷内酯类化合物的研究进展,包括其结构及药理活性两个方面,列举了从23 种植物中分到的114 个艾里莫芬烷内酯类化合物,同时也对其主要生物活性进行了总结。 This dissertation consists of three chapters. The first and second chapters elaborate the phytochemical investigation of Uncaria rhynchophylla and Ligularia fischeri. Thirty-seven compounds, including six new ones, were isolated and identified by spectroscopic methods and X-ray diffraction experiments. The third chapter is a review on the study progress of Eremophilanolides. The first chapter focus on the isolation and identification of chemical constituents from Uncaria rhynchophylla. Twenty-two compounds were isolated from the roots of U. rhynchophylla by repeat column chromatography over normal and reversed phase silica gel. Those compounds mainly belonged pentacyclic triterpenoids and sphingolipids. Among them, a series homologues of six sphingolipids were new compounds and seven compounds were firstly reported in this plant. The second chapter is about the phytochemical investigation of L. fischeri. Eighteen compounds were isolated and identified. Among them, four new erem-ophilanolides and a new dinoreremophilane derivative were characterized as 3β-acetyl-6β, 8α, 10β-trihydroxyeremophila-7(11)-en-8, 12-olide (23), 3β-acetyl-8β, 10β-dihydroxy-6β-(2-methylbutyryloxy)-eremophilenolide (24), 3β-acetyl-6β, 10β-dihydroxyeremophila-7(11), 8(9)-dien-8,12-olide (25), 3β-acetyl-6β, 10α-dihydroxyeremophila- 7(11), 8(9)-dien-8,12-olide (26), (3aR,4R,5S,7aS)-2-acetyl-7a-hydroxy-3a, 4, 5, 6,7, 7a-hexahydro-1H-inden-5-yl acetate (27) by spectroscopic analysis and confirmed by X-ray crystallography analysis. It was revealed that compound 23 has the ability to inhabit the PTP1B in vivo. And its IC50 is 1.30 μg/ml. The third part is a review on the study progress of Eremophilanolides.

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Hopanoids are pentacyclic triterpenoids that are thought to be bacterial surrogates for eukaryotic sterols, such as cholesterol, acting to stabilize membranes and to regulate their fluidity and permeability. To date, very few studies have evaluated the role of hopanoids in bacterial physiology. The synthesis of hopanoids depends on the enzyme squalene-hopene cyclase (Shc), which converts the linear squalene into the basic hopene structure. Deletion of the 2 genes encoding Shc enzymes in Burkholderia cenocepacia K56-2, BCAM2831 and BCAS0167, resulted in a strain that was unable to produce hopanoids, as demonstrated by gas chromatography and mass spectrometry. Complementation of the Delta shc mutant with only BCAM2831 was sufficient to restore hopanoid production to wild-type levels, while introducing a copy of BCAS0167 alone into the Delta shc mutant produced only very small amounts of the hopanoid peak. The Delta shc mutant grew as well as the wild type in medium buffered to pH 7 and demonstrated no defect in its ability to survive and replicate within macrophages, despite transmission electron microscopy (TEM) revealing defects in the organization of the cell envelope. The Delta shc mutant displayed increased sensitivity to low pH, detergent, and various antibiotics, including polymyxin B and erythromycin. Loss of hopanoid production also resulted in severe defects in both swimming and swarming motility. This suggests that hopanoid production plays an important role in the physiology of B. cenocepacia.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The hexane-soluble fractions from the rhizomes or from the leaves from five Dorstenia (Moraceae) species (D. bahiensis Kl., D. bryoniifolia Mart ex. Miq., D. carautae C.C.Berg, D. cayapiaa Vell. and D. heringerii Car. & Val) were analysed by HRGC-MS (high-resolution gas chromatography - mass spectrometry). Pentacyclic triterpenes, steroids and furocoumarins were identified. HRGC-MS is shown to be a valuable tool for the analysis of terpenoidal compounds from Dostenia species. These compounds may be related to the folk utilization of Dorstenia species as antiophidicals.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Sediments from Holes 994C, 995A, 997A, and 997B have been investigated for "combined" gases (adsorbed gas and that portion of free gas that has not escaped from the pore volume during core recovery and sample collection and storage), solvent-extractable organic compounds, and microscopically identifiable organic matter. The soluble materials mainly consist of polar compounds. The saturated hydrocarbons are dominated by n-alkanes with a pronounced odd-even predominance pattern that is derived from higher plant remains. Unsaturated triterpenoids and 17ß, 21ß-pentacyclic triterpenoids are characteristic for a low maturity stage of the organic matter. The low maturity is confirmed by vitrinite reflectance values of 0.3%. The proportion of terrestrial remains (vitrinite) increases with sub-bottom depth. Within the liptinite fraction, marine algae plays a major role in the sections below 180 mbsf, whereas above this depth sporinites and pollen from conifers are dominant. These facies changes are confirmed by the downhole variations of isoprenoid and triterpenoid ratios in the soluble organic matter. The combined gases contain methane, ethane, and propane, which is a mixture of microbial methane and thermal hydrocarbon gases. The variations in the gas ratios C1/(C2+C3) reflect the depth range of the hydrate stability zone. The carbon isotopic contents of ethane and propane indicate an origin from marine organic matter that is in the maturity stage of the oil window.

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C 15H 1602 (a synthetic precursor to dodecahedrane), monoclinic, P21/n, a = 12.171 (5), b = 6.976(5), c = 13.868 (3) A, B = 102.56 (3) ° , Z = 4, D m = 1.30, D c = 1.318 g cm -3, F(000) = 488, g(Mo K¢t) = 0.92 cm- 1. Intensity data were collected on a Nonius CAD-4 diffractometer and the structure was solved by direct methods. Full-matrix least-squares refinement gave R = 0.077 (R w = 0.076) for 1337 observed reflections. All the five-membered rings are cis fused and have envelope (C s symmetry) conformations.

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Abstract is not available.

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Enantiospecific synthesis of ABC-ring systems of A-nor and abeo 4(3 -> 2) tetra and pentacyclic triterpenes has been accomplished starting from the readily available monoterpene (R)-carvone. (R)-Carvone was used as the B-ring of the target molecules. A lithium-liquid ammonia mediated cyclisation of delta,epsilon-unsaturated ester was employed for the cyclopentannulation at the C-5 and C-6 carbons of carvone and an RCM reaction was employed for the cyclohexannulation to generate the ABC-ring system of A-nor tetra and pentacyclic triterpenes. The strategy has been extended for the synthesis of the ABC-ring system of abeo 4(3 -> 2) tetra and pentacyclic triterpenes. (C) 2009 Elsevier Ltd. All rights reserved.

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(I)Lantadene-B: C35H52O5,M r =552.80, MonoclinicC2,a=25.65(1),b=6.819(9),c=18.75(1) Å,beta=100.61(9),V=3223(5) Å3,Z=4,D x =1.14 g cm–3 CuKagr (lambda=1.5418A),mgr=5.5 cm–1,F(000)=1208,R=0.118,wR=0.132 for 1527 observed reflections withF o ge2sgr(F o ). (II)Lantadene-C: C35H54O5·CH3OH,Mr=586.85, Monoclinic,P21,a=9.822(3),b=10.909(3),c=16.120(8)Å,beta=99.82(4),V=1702(1)Å3,Z=2,D x =1.145 g cm–3, MoKagr (lambda=0.7107Å), mgr=0.708 cm–1 F(000)=644,R=0.098, wR=0.094 for 1073 observed reflections. The rings A, B, C, D, and E aretrans, trans, trans, cis fused and are in chair, chair, sofa, half-chair, chair conformations, respectively, in both the structures. In the unit cell the molecules are stabilized by O-HctdotO hydrogen bonds in both the structures, however an additional C-HctdotO interaction is observed in the case of Lantadene-C.

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In order to gain access to the heptacyclic tetraone 3, efforts were directed towards the utilisation of the major 'unwanted' [4 + 2]-adduct 11 of tetrachlorodimethoxycyclopentadiene and norbornenobenzoquinone. Epoxides derived from the diol and dimethoxy derivatives of the adduct 11 undergo facile Wagner-Meerwein rearrangement resulting in the required endo, syn, endo stereochemistry as well as methano-bridge functionalisation to deliver 18 and 24, respectively. However, intramolecular ether formation, occurring via the capture of carbocation intermediate with the transannularly poised oxygen functionality, is a more facile process. Attempts to cleave the ether linkage resulted in the formation of a novel transannularly cyclised twisted bowl shape heptacyclic compound 30 and its structure has been established through X-ray crystallography.

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Triterpenoids are pentacyclic secondary metabolites present in many terrestrial plants. Natural triterpenoids have been reported to exhibit anti-inflammatory and anti-carcinogenic activities. Here, we show that modifications of ring A of boswellic acid (2 cyano, 3 enone) resulted in a highly active growth inhibitory, anti-inflammatory, pro-differentiative and anti-tumour triterpenoid compound called cyano enone of methyl boswellates (CEMB). This compound showed cytotoxic activity on a number of cancer cell lines with IC50 ranging from 0.2 to 0.6 mu M. CEMB inhibits DNA synthesis and induces apoptosis in A549 cell line at 0.25 mu M and 1 mu M concentrations, respectively. CEMB induces adipogenic differentiation in 3T3-L1 cells at a concentration of 0.1 mu M. Finally, administration of CEMB intra-tumourally significantly inhibited the growth of C6 glioma tumour xenograft in immuno-compromised mice. Collectively, these results suggest that CEMB is a very potent anti-tumour compound.