897 resultados para 1D and 2D NMR


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Neste trabalho estamos reportando o isolamento de cinco compostos de Aspergillus sp EJC08 isolado como endofítico de Bauhinia guianensis uma planta típica da Amazônia. Os compostos ergosterol (1), peróxido de ergosterol (2), mevalolactona (3), monometilsulocrina (4) e tripacidina A (5) foram isolados através de procedimentos cromatográficos e identificados por métodos espectrais de RMN 1D e 2D e EM. Os compostos 3, 4 e 5 foram testados contra Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis e Staphylococcus aureus e mostraram boa atividade.

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

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We report the synthesis and total NMR characterization of 5-thia-1-azabicyclo-[4.2.0]oct-2-ene-2-carboxylic acid-3-[[[(4″- nitrophenoxy)carbonyl]oxy]-methyl]-8-oxo-7-[(2-thienyloxoacetyl)amino] -diphenylmethyl ester-5-dioxide (5), a new cephalosporin derivative. This compound can be used as the carrier of a wide range of drugs containing an amino group. The preparation of the intermediate product, 5-thia-1-azabicyclo[4.2.0] oct-2-ene-2-carboxylic acid-3-[methyl 4-(6-methoxyquinolin-8-ylamino) pentylcarbamate]-8-oxo-7-[(2-thienyloxoacetyl)amino]-diphenylmethyl ester-5-dioxide (6), as well as the synthesis of the antimalarial primaquine prodrug 5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid-3-[methyl 4-(6-methoxyquinolin-8-ylamino)pentylcarbamate]-8-oxo-7-[(2-thienyloxoacetyl) amino]- 5-dioxide (7) are also described, together with their total 1H- and 13C-NMR assignments. © 2008 by MDPI.

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A phytochemical study of the ethyl acetate extract of the roots and adventitious roots of Spirotropis longifolia, a monodominant tree species of the Guianan rainforest, has allowed the isolation of three compounds: 2- hydroxy-8,9-methylenedioxy-2',2'-dimethylpyrano-[5',6':4,3]-6a-prenyl-[6aS,11aS]-pterocarpan (spirotropin A), 2-hydroxy-8,9-methylenedioxy-2',2'-dimethy1-3',4'-dihydropyrano-[5',6':4,3]-6a-prenyl-(6aS,11aS]-pterocarpan (spirotropin B), and 5,7-dihydroxy-6.8-dipreny1-2 ''''.2 ''''-dimethylpyrano[5 '''',6 '''': 3',4]-isoflavone (spirotropone). In addition, 10 known compounds, trans-oxyresveratrol, trans-resveratrol, piceatannol, daidzein, genistein, isoprunetin, lupeol, latifolol, gnetin D and gnetin E, were also isolated. These compounds were evaluated for their antifungal activity and their cytotoxicity, and their structures were established by 1D and 2D NMR, HRMS, CD and optical rotation measurements. (C) 2011 Elsevier Ltd. All rights reserved.

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Two new cyclohexenones (antheminones A and B) and a new cyclohexanone, (antheminone C) along with five known compounds were isolated from the leaves of Anthemis maritima L. The structures were mainly deduced from extensive 1D and 2D NMR spectroscopy and mass spectrometry. The new compounds were tested in vitro for their cytotoxic activity against adherent and non-adherent cancer cell lines. Antheminones A and C exhibited significant antiproliferative activity against leukemia cells with IC(50) values ranging from 3.2 to 14 microM.

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Plants produce a number of substances and products and primary and secondary metabolites (SM) are amongst them with many benefits but limitation as well. Usually, the fodder are not considered toxic to animals or as a source having higher SM. The Brachiaria decumbens has a considerable nutritional value, but it is considered as a toxic grass for causing photosensitization in animals, if the grass is not harvested for more than 30 days or solely. The absence of detailed information in the literature about SM in Brachiaria, metabolites production and its chemical profile enable us to focus not only on the nutritive value but to get answers in all aspects and especially on toxicity. The study was conducted in the period of december 2013 to december 2014; in greenhouse FZEA-USP. B. decumbens was used with two cutting heights (10 and 20 cm) and nitrogen doses (0, 150, 300 and 450 kg ha-1) in complete randomized block design. The bromatological analysis were carried out on near infrared spectroscopy. Generally, the application of 150 kg ha-1 N was sufficient to promote the nutritional value in B. decumbens but above it the nitrogen use efficiency decline significantly. The highest dry matter yield (99.97 g/pot) was observed in autumn and the lowest was in winter (30.20 g/pot). While, as per nitrogen dose the average highest dry matter yield was at 150 kg ha-1 (79.98 g/pot). The highest crude protein was observed in winter (11.88%) and the lowest in autumn (7.78%). By the cutting heights; the 10 cm proved to have high CP (9.51%). In respect of fibrous contents, the highest acid detergent fiber was noted in summer (36.37%) and lowest in winter (30.88%). While the neutral detergent fiber was being highest in autumn and lowest in spring (79.60%). The highest in vitro dry matter and organic matter digestibilities were noted at 300 kg ha-1 N; being 68.06 and 60.57%; respectively; with the lowest observed in without N treatments (62.63% and 57.97), respectively. For determination of the classes, types and concentration of SM in B. decumbens, phytochemical tests, thin layer and liquid chromatography-mass spectrometry and nuclear magnetic resonance analysis were carried out. Height, nitrogen and seasons significantly (P <0.0001) affected the secondary metabolic profile. A new protodioscin isomer (protoneodioscin (25S-)) was identified for first time in B. decumbens and is supposed to be the probable toxicity reason. Its structure was verified by 1D and 2D NMR techniques (1H, 13C) and 1D (COSY-45, edited HSQC, HMBC, H2BC, HSQC -TOCSY, NOESY and 1 H, 1 H, J). All factors influence the metabolic profile significantly (P <0.0001). The lowest phenols were at 300 kg ha-1 while the lowest flavones were at 0 kg ha-1. Season wise the highest phenols occurred in autumn (19.65 mg/g d.wt.) and highest flavones (28.87 mg/g d.wt.) in spring. Seasons effect the saponin production significantly (P <0.0001) and the results showed significant differences in the protodioscin (17.63±4.3 - 22.57±2.2 mg/g d.wt.) and protoneodioscin (23.3±1.2 - 31.07±2.9 mg/g d.wt.) concentrations. The highest protodioscin isomers concentrations were observed in winter and spring and by N doses the highest were noted in 300 kg ha-1. Simply, all factors significantly played their role in varying concentrations of secondary metabolites.

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A new steroidal saponin, shatavarin V, (3-O-{[alpha-L-rhamnopyranosy](1-2)][beta-D-glucopyranosyl(1 -> 4)]-beta-D-glucopyranosyl}-(25S)-5 beta-spirostan-3 beta-ol), was isolated from the roots of Asparagus racemosus by RP-HPLC, and its structure determined by 1D and 2D NMR studies. This data permits clarification of the structures reported for several known saponins: asparinins A and B; asparosides A and B; curillin H; curillosides G and H and shavatarins I and IV. (c) 2006 Elsevier Ltd. All rights reserved.

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The effect of stainless steel, glass, zirconium and titanium enamel surfaces on the thermal and photooxidative toughening mechanism of dehydrated castor oil films deposited on these surfaces was investigated using different analytical and spectroscopic methods. The conjugated and non-conjugated double bonds were identified and quantified using both Raman spectroscopy and 1D and 2D NMR spectroscopy. The disappearance of the double bonds in thermally oxidised oil-on-surface films was shown to be concomitant with the formation of hydroperoxides (determined by iodometric titration). The type of the surface had a major effect on the rate of thermal oxidation of the oil, but all of the surfaces examined had resulted in a significantly higher rate of oxidation compared to that of the neat oil. The highest effect was exhibited by the stainless steel surface followed by zirconium enamel, titanium enamel and glass. The rate of thermal oxidation of the oil-on-steel surface (at 100 °C, based on peroxide values) was more than five times faster than that of oil-on-glass and more than 21 times faster than the neat oil when compared under similar thermal oxidative conditions. The rate of photooxidation at 60 °C of oil-on-steel films was found to be about one and half times faster than their rate of thermal oxidation at the same temperature. Results from absorbance reflectance infrared microscopy with line scans taken across the depth of thermally oxidised oil-on-steel films suggest that the thermal oxidative toughening mechanism of the oil occurs by two different reaction pathways with the film outermost layers, i.e. furthest away from the steel surface, oxidising through a traditional free radical oxidation process involving the formation of various oxygenated products formed from the decomposition of allylic hydroperoxides, whereas, in the deeper layers closer to the steel surface, crosslinking reactions predominate.

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Several ester derivatives of rosmarinic acid (rosmarinates) were synthesised, characterised (1D and 2D NMR, UV and FTIR spectroscopy) and tested for their potential use as antioxidants derived from a renewable natural resource. The intrinsic free radical scavenging activity of the rosmarinates was assessed, initially using a modified DPPH (2, 2-diphenyl-1-picrylhydrazyl radical) method, and found to be higher than that of commercial synthetic hindered phenol antioxidants Irganox 1076 and Irganox 1010. The thermal stabilising performance of the rosmarinates in polyethylene (PE) and polypropylene (PP) was subsequently examined and compared to that of samples prepared similarly but in the presence of Irganox 1076 (in PE) and Irganox 1010 (in PP) which are typically used for polyolefin stabilisation in industrial practice. The melt stability and the long-term thermo-oxidative stability (LTTS) of processed polymers containing the antioxidants were assessed by measuring the melt flow index (MFI), melt viscosity, oxidation induction time (OIT) and long-term (accelerated) thermal ageing performance. The results show that both the melt and the thermo-oxidative stabilisation afforded by the rosmarinates, and in particular the stearyl derivative, in both PE and PP, are superior to those of Irganox 1076 and Irganox 1010, hence their potential as effective sustainable bio-based antioxidants for polymers. The rosmarinic acid used for the synthesis of the rosmarinates esters in this study was obtained from commercial rosemary extracts (AquaROX80). Furthermore, a large number of different strains of UK-grown rosemary plants (Rosmarinum officinalis) were also extracted and analysed in order to examine their antioxidant content. It was found that the carnosic and the rosmarinic acids, and to a much lesser extent the carnosol, constituted the main antioxidant components of the UK-plants, with the two acids being present at a ratio of 3:1, respectively.

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Hemoproteins are a very important class of enzymes in nature sharing the essentially same prosthetic group, heme, and are good models for exploring the relationship between protein structure and function. Three important hemoproteins, chloroperoxidase (CPO), horseradish peroxidase (HRP), and cytochrome P450cam (P450cam), have been extensively studied as archetypes for the relationship between structure and function. In this study, a series of 1D and 2D NMR experiments were successfully conducted to contribute to the structural studies of these hemoproteins. ^ During the epoxidation of allylbenzene, CPO is converted to an inactive green species with the prosthetic heme modified by addition of the alkene plus an oxygen atom forming a five-membered chelate ring. Complete assignment of the NMR resonances of the modified porphyrin extracted and demetallated from green CPO unambiguously established the structure of this porphyrin as an NIII-alkylated product. A novel substrate binding motif of CPO was proposed from this concluded regiospecific N-alkylation structure. ^ Soybean peroxidase (SBP) is considered as a more stable, more abundant and less expensive substitute of HRP for industrial applications. A NMR study of SBP using 1D and 2D NOE methods successfully established the active site structure of SBP and consequently fills in the blank of the SBP NMR study. All of the hyperfine shifts of the SBP-CN- complex are unambiguously assigned together with most of the prosthetic heme and all proximal His170 resonances identified. The active site structure of SBP revealed by this NMR study is in complete agreement with the recombinant SBP crystal structure and is highly similar to that of the HRP with minor differences. ^ The NMR study of paramagnetic P450cam had been greatly restricted for a long time. A combination of 2D NMR methods was used in this study for P450cam-CN - complexes with and without camphor bound. The results lead to the first unequivocal assignments of all heme hyperfine-shifted signals, together with certain correlated diamagnetic resonances. The observed alternation of the assigned novel proximal cysteine β-CH2 resonances induced by camphor binding indicated a conformational change near the proximal side.^

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In the Hydrocarbon exploration activities, the great enigma is the location of the deposits. Great efforts are undertaken in an attempt to better identify them, locate them and at the same time, enhance cost-effectiveness relationship of extraction of oil. Seismic methods are the most widely used because they are indirect, i.e., probing the subsurface layers without invading them. Seismogram is the representation of the Earth s interior and its structures through a conveniently disposed arrangement of the data obtained by seismic reflection. A major problem in this representation is the intensity and variety of present noise in the seismogram, as the surface bearing noise that contaminates the relevant signals, and may mask the desired information, brought by waves scattered in deeper regions of the geological layers. It was developed a tool to suppress these noises based on wavelet transform 1D and 2D. The Java language program makes the separation of seismic images considering the directions (horizontal, vertical, mixed or local) and bands of wavelengths that form these images, using the Daubechies Wavelets, Auto-resolution and Tensor Product of wavelet bases. Besides, it was developed the option in a single image, using the tensor product of two-dimensional wavelets or one-wavelet tensor product by identities. In the latter case, we have the wavelet decomposition in a two dimensional signal in a single direction. This decomposition has allowed to lengthen a certain direction the two-dimensional Wavelets, correcting the effects of scales by applying Auto-resolutions. In other words, it has been improved the treatment of a seismic image using 1D wavelet and 2D wavelet at different stages of Auto-resolution. It was also implemented improvements in the display of images associated with breakdowns in each Auto-resolution, facilitating the choices of images with the signals of interest for image reconstruction without noise. The program was tested with real data and the results were good

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A novel norsesquiterpene glucoside ptesculentoside has been isolated from the Australian bracken Pteridium esculentum, together with the known bracken carcinogen ptaquiloside and lesser amounts of caudatoside. The structure of ptesculentoside is determined by analysis of 1D and 2D NMR spectra, and via its conversion into previously known pterosin G.

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Four novel highly oxygenated trinortriterpenoids, sphenalactones A-D (1-4), were isolated from the leaves and stems of Schisandra sphenanthera and their structures were elucidated by extensive analysis of 1D and 2D NMR data. Compounds 1-4 featured a C-27

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This study investigated the 70% aqueous acetone extract of the fruits of Schisandra rubriflora which led to the isolation of eight lignans, including a new isolate, rubrisandrin C (1), and seven known lignans (2-8). The structure of 1 was established by extensive 1D and 2D NMR spectroscopy and its absolute stereochemistry was determined by CD spectrum. Compounds 1-5 and 7-8 were evaluated for their anti-HIV-1 activity that showed inhibitory activity on HIV-1(IIIB) induced syncytium formation with EC50 values in the range of 2.26 similar to 20.4 mu g/mL. Compounds 1 and 7 exerted their obvious protection of HIV-1(IIIB) inducted MT-4 host cells lytic effects with a selectivity index of 15.4 and 24.6, respectively.

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本论文由四部分组成。第一部分报道了佛手参提取物的化学成分研究,建立了活性成分含量测定的高效液相测定和指纹图谱研究,采用液质联用技术鉴定了主要色谱峰;第二部分报道了丹参及其复方制剂的特征图谱研究;第三部分探讨了两面针生物碱的电喷雾质谱裂解规律,并采用液质联用技术分离鉴定了提取物中的多种生物碱。第四部分概述了液质联用在药物代谢研究中的运用。 第一部分包括第一、第二和第三章。第一章针对佛手参(Gymnadeniaconopsea)块茎的甲醇提取物,采用大孔树脂和反相硅胶柱层析等各种分离方法,共分离鉴定出4 个化合物,通过波谱分析将它们的结构确定为dactylorhin B (1)、loroglossin (2)、dactylorhin A (3)和militarine (4)。这4 个化合物均是首次从佛手参中分离得到的琥珀酸葡萄糖苷类成分。第二章采用高效液相色谱法对西藏、四川、河北、青海和尼泊尔等不同地区产的十个佛手参样品进行腺嘌呤核苷和对羟基苯甲醇的定量分析,结果表明这2 个成份可视为佛手参的特征成分,但也注意到产地不同该2 个特征成分的含量也有所不同。第三章采用标准中药指纹图谱相似度计算软件,以10 个佛手参样品HPLC 图谱的平均值为相似性评价对照模板,对10 个样品进行了相似度评价,并经液质联用分析指认了7 个共有峰,分别为腺嘌呤核苷(1)、对羟基苯甲醇(2)、对羟基苯甲醛(3) 、dactylorhin B(4) 、loroglossin(5)、dactylorhin A(6)和militarine(7)。 第二部分包括第四、第五、第六和第七章。第四章运用电喷雾质谱检测了对照药材和五个不同产地的丹参药材中脂溶性和水溶性成分,系统地探讨了多种成分的电喷雾质谱规律,并以对照药材为标准建立了特征指纹图谱。五个产地的药II材通过与对照药材相对比,采用聚类分析的方法,得到了定性的鉴别与判断。并采用液质联用技术对丹参药材提取液中的化学成份进行分析,推测了九个特征峰,并对六样品的液相色谱图进行了聚类分析。第五章探讨了三七皂苷的电喷雾质谱电离和裂解规律,并采用电喷雾质谱法对三七标准药材,血通片中的皂苷成分进行了分析。第六章运用电喷雾质谱研究复方丹参片提取液的特征图谱,并和单味药材丹参和三七的特征图谱进行了对比研究。并运用HPLC-ESI MSn 分析鉴定了复方丹参片提取液中的化学成分,推测了12 个色谱峰。第七章总结了电喷雾质谱和液质联用技术在丹参药材,三七药材及复方丹参制剂中的运用的优势和局限性。 第三部分(第八章)研究了两面针生物碱中二氢白屈菜红碱(1)、二氢两面针碱(2)、8-酮基二氢白屈菜红碱(3)、8-丙酮基二氢两面针碱(4)、两面针碱(5)、和1,3-二(8-二氢两面针碱)丙酮(6)等六个苯并菲啶型生物碱的电喷雾质谱裂解规律,其中二氢两面针碱和二氢白屈菜红碱,8-丙酮基二氢两面针碱和8-酮基二氢白屈菜红碱是两对二个甲氧基分别在C-9 和C-10,C-10 和C-11 的同分异构体。实验结果表明,在相同的碰撞能下,这类位置异构体的ESI MS2 质谱二级碎片离子的相对峰度存在很大差异,这可以用于区分该类同分异构体,采用液-质联用可以对两面针的总生物碱提取物中的这些同分异构体加于区分。同时在本实验采用的液相色谱条件下,多种生物碱得到较好的分离,通过和对照品的保留时间,紫外吸收光谱及电喷雾质谱图对照,鉴定了11 个主要色谱峰。 第四部分(第九章)对液质联用技术在药物代谢中的运用进行了综述。 This dissertation consisted of four sections. The first two sections elaborated thephytochemical investigation of the rhizomes Gymnadenia conopsea R. Br., methoddevelopment for rapid identifying and qutifying the chemical condtituent of thistibetant medicine, and the chemical fingerprint analysis of rhizomes of G. conopsea,Salviae miltiorrhiza and P. notoginseng. The third section studied the fragmentationmechanism of six alkaloids from Zanthoxylum nitidium and method development forrapid identifying varieties of alkaloids from the extract of this herbal medicine. Thefourth section reviewed HPLC- MS method in drug metabolism studies. The first section consisted of chapters 1, 2, 3. Chapter 1 elaborated the phytochemicalinvestigation of Gymnadenia conopsea R. Br. Four succinate derivative esters wereisolated from the methanol extract of the rhizomes of G. conopsea through repeatedcolumn chromatography on normal and reversed phase silica gel, their structures weredetermined by ESI-MS, 1D and 2D NMR evidence. They were firstly discoveredfrom this species. In chapter 2, a high-performance liquid chromatography.diodearray detection (HPLC-DAD) method has been firstly developed for quantitation oftwo characteristic constituents, adenosine and 4-hydroxybenzyl alcohol, from theextract of rhizomes of G. conopsea. All 10 samples of G. conopsea contained differentamount of adenosine and 4-hydroxybenzyl alcohol. Adenosine and the4-hydroxybenzyl alcohol can be applied in identification and quality control for theroots of G. conopsea. In chapter 3, a high-performance liquid chromatography.diodearray detection.tandem mass spectrometry (HPLC-DAD-MSn) method has been firstly developed for chemical fingerprint analysis of rhizomes of G. conopsea andrapid identification of major compounds in the fingerprints. Comparing the UV andMS spectra with those of authentic compounds, seven main peaks in the fingerprintswere identified as adenosine, 4-hydroxybenzyl alcohol, 4-hydroxybenzyl aldehyde,dactylorhin B, loroglossin, dactylorhin A and militarine. The Computer AidedSimilarity Evaluation System for Chromatographic Fingerprint of TraditionalChinese Medicine (CASES) was employed to evaluate the similarities of 10 samplesof the rhizomes of G. conopsea collected from Sichuan, Qinghai and Hebei provincesand Tibet autonomous region of China, and Nepal. These samples from differentsources had similar chemical fingerprints to each other. The second section consisted of chapters 4, 5, 6 and 7. In chapter 4,both thecharacteristic spectra of liposoluble tanshinones and aqueous-soluble salvianolic acidswere established by the electrospray ionization mass spectrometry (ESI MS)technique and the differences between standard and crude rhizomes of Salviaemiltiorrhiza Bge. from 5 sources were analyzed. The law of electrospray ion trap mass(ESI ITMS) of typical tanshinones and salvianolic acids is studied.The analysis of the chemical constituent of rhizomes of Salviae miltiorrhiza Bge. byliquid chromatography coupled with mass spectrum (LC/MS) technique wasestablished,and the distances among standard herb and crude herb from 5 sourceswere calculated by clustering analysis. According the DAD spectra and MS2 data,9tanshinones could be speculated. In chapter 5, the character spectra of total saponinsin P. notoginseng extracts were established by ESI ITMS and selective ion monitoring(SIM) technology. The law of notoginsenosides by ESI MS2 was studied. In chapter 6,the characteristic spectra of Compound Danshen Tablet established and compared byESI-MS and HPLC/DAD/MS, 6 known tanshinones and 3 saponins were speculated.In chapter 7, the advantage and disadvantage of the strategy, using the ESI ITMS andLC/MS techniques for study of characteristic spetra of danshen and Compound Danshen Tablet, were summerized. The third section (chapter 8) studied the fragmentation mechanism of six alkaloids,dihydronitidine, dihydrochelerythrine, 8-acetonyl dihydronitidine,8-acetonyldrochelerythrine, nitidine and 1,3-bis (8-dihydronitidinyl)-acetone, by ESIMSn. Tandem mass spectrometry experiments indicated that different substitutionsites of the methoxyl groups at C-9 and C-10 or at C-10 and C-11 determined thedifferent abundances of the MS2 fragmentation ions using the same collision energy.According to the different abundances of MS2 product ions, positional isomericbenzo[c] phenanthridine alkaloids can be differentiated. Moreover, ten constituents inthe crude alkaloids extract from the roots of Zanthoxylum nitidium were rapidlyidentified by high-performance liquid chromatography coupled with tandem massspectrometry (HPLC-MSn), through comparing the retention times and ESI MSn spectra with the authentic standards. The fourth section (chapter 9) is a review on HPLC-MS method development in drug metabolism studies.