997 resultados para vanillic acid
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Valko- ja ruskolahosienet tunnetaan luonnossa tehokkaimpina puun ja karikkeen lignoselluloosan lahottajina. Valkolahosienet pystyvät hajottamaan kaikkia puun osia: ligniiniä, selluloosaa ja hemiselluloosaa. Selektiivisesti ligniiniä hajottavat sienet lahottavat puusta suhteessa enemmän vaikeasti hajoavaa ligniiniä kuin selluloosaa tai hemiselluloosaa, jolloin jäljelle jää valkoista ja miltei puhdasta selluloosaa. Bioteknisissä sovelluksissa juuri selektiviiviset valkolahottajat ovat kiinnostavia. Niiden avulla voidaan puuhaketta esikäsitellä esimerkiksi paperinvalmistuksessa haitallisen ligniinin poistamiseksi. Ruskolahosienet ovat huomattavia puun, puutavaran ja puisten rakenteiden lahottajia, kuten tässä työssä käytetty Gloeophyllum trabeum (saunasieni ) ja Poria (Postia) placenta (istukkakääpä). Ruskolahosienet hajottavat puusta hemiselluloosan lisäksi selluloosaa, jolloin jää jäljelle ruskea ja jauhomaiseksi mureneva ligniini. Ruskolahosienet muovaavat ligniiniä jonkin verran. Kahden ruskolahosienen G. trabeumin ja P. placentan lisäksi tutkittiin valkolahosieniä, joista Ceriporiopsis subvermispora (karstakääpä) ja harvinainen Physisporinus rivulosus -sieni (talikääpä) hajottavat ligniiniä erittäin selektiivisesti. Phanerochaete chrysosporium on kaikkialla paljon tutkittu sieni, ja Phlebia radiata valkolahosientä (rusorypykkä) on tutkittu paljon mikrobiologian osastolla. Lisäksi tutkittiin Phlebia tremellosa -sienten (hytyrypykkä) ligninolyyttisten entsyymien tuottoa ja 14C-leimatun synteettisen ligniinin (DHP) hajotusta. P. radiata ja P. tremellosa -sienten on todettu aiemmin hajottavan ligniiniä selektiivisesti. Työssä selvitettiin miten sienten kasvua voi mitata, miten vertailukelpoisia eri mittaamismenetelmillä saadut tulokset ovat ja ilmenevätkö sienten aktiivisimmat kasvuvaiheet samaan aikaan eri menetelmillä mitattuna. Tärkeimmät tulokset olivat seuraavat havainnot: (i) P. radiata ja P. tremellosa -sienikannat tuottivat ligniini- ja mangaaniperoksidaasientsyymejä (LiP ja MnP) sekä lakkaasia, ja sienistä puhdistettiin 2-3 LiP- ja P. radiatasta yksi MnP-entsyymi; (ii) P. tremellosa -sienet hajottivat leimattua synteettistä ligniiniä (DHP) yhtä hyvin kuin paljon tutkitut P. chrysosporium ja P. radiata -sienet; (iii) puu, sienen luonnollinen kasvualusta, lisäsi valkolaho- ja ruskolahosienten demetoksylaatiota [O14CH3]-leimatusta ligniinin malliyhdisteestä 14CO2:ksi ilman puuta olleeseen alustaan verrattuna; (iv) demetoksylaatio (14CO2:n tuotto) oli normaalissa ilma-atmosfäärissä useimmiten parempi happeen verrattuna; (v) hapessa paras 14CO2:n tuotto saatiin puupalakasvatuksissa, joihin oli lisätty ravinnetyppeä tai typen lisäksi glukoosia sekä valkolaho- että ruskolahosienillä; (vi) ilmassa 14CO2:n tuotto oli puulla voimakkainta valkolahosienillä ilman lisäravinteita, kun taas G. trabeum -sienellä se oli yhtä hyvä eri alustoissa; (vii) biomassan muodostuminen rihmastojen ergosterolipitoisuuksista mitattuna oli ruskolahosienillä parempi kuin valkolahosienillä; (viii) ja biomassojen huippupitoisuudet olivat 6:lla sienellä eri suuruisia ja niiden maksimimäärien ajankohdat vaihtelivat viiden viikon kasvatusten kuluessa. Mikrobiologian osastolla Viikissä eristetty ja paljon tutkittu P. radiata -valkolahosieni oli mukana kaikissa tehdyissä kokeissa. Sienen LiP-aktiivisuus ja 14CO2:n tuotto 14C-rengas-leimatusta synteettisestä ligniinistä (DHP) korreloivat erittäin hyvin. Biomassan muodostuminen ergosterolilla määritettynä tuki hyvin entsyymiaktiivisuusmittauksilla ja isotooppikasvatuksilla saatuja tuloksia.
Resumo:
Four new cocrystals of a well studied active pharmaceutical ingredient (API), namely, pyrazinecarboxamide (PZA), with various monocarboxylic acids equipped with additional hydrogen bonding sites such as vanillic acid (VA), gallic acid (GA), 1-hydroxy-2-naphthoic acid (1HNA), and indole-2-carboxylic acid (I2CA) have been successfully prepared and characterized by FTIR, H-1 NMR, differential scanning calorimetry (DSC), and single crystal and powder X-ray diffraction (SXRD and PXRD, respectively) techniques. In the majority of the cases, preferential occurrence amide amide and acid acid homosynthons has been observed. Since the heterosynthon is energetically preferred to homosynthon, such unusual occurrence of homosynthon in these cocrystals is intriguing.
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本论文由四部分组成,前三部分为实验论文,第四部分为文献综述。第一、二部分分别报道了中药西藏胡黄连和鸡矢藤的化学成分研究结果。从两种药用植物中共分离和鉴定了32个化学成分,其中3个为新化合物。第三部分为黄芪多糖的提取工艺研究。第四部分概述了近年来植物多糖的研究进展。 第一章为西藏胡黄连化学成分研究。通过正、反相硅胶柱层析等分离方法从药用植物西藏胡黄连(Picrorhiza scrophulariiflora Pennell)的根茎中共分离纯化出7个化合物。运用MS、1H-NMR、13C-NMR、DEPT、HSQC和HMBC等现代谱学方法,结合理化分析对这些化合物的结构进行了分析鉴定。7个化合物中有两个是酚性的葡萄糖苷类成分:西藏胡黄连酚苷D (1)、4-O-β-D-(6-O-vanilloyl glucopyranosyl) vanillic acid (6);四个苯乙基苷类化合物:plantamajoside (2)、plantainoside D (3)、西藏胡黄连苷A (4) 和西藏胡黄连苷F (5);一个苯基小分子化合物:香豆酸甲酯 (7)。其中化合物1和5未见文献报道,确定为新化合物;化合物3为首次从该种植物中分到。 第二章为鸡矢藤化学成分研究。从鸡矢藤(Paederia scandense (Lour) Merrill)全草中分离出25个化合物,通过理化常数和波谱数据鉴定了它们的结构。25个化合物中包括一个蒽醌类成分:茜根定-1-甲醚 (1);两个香豆素:异东莨菪香豆素 (2)和5-羟基-8-甲氧基吡喃香豆素 (3);两个香豆素-木脂素化合物:臭矢菜素 B (4)和臭矢菜素 D (5);一个木脂素:异落叶松树脂醇 (6);两个黄酮:diadzein (7)和蒙花苷 (8);三个三萜类化合物:齐墩果酸 (9)、乌苏酸 (10)和 3-O-β-D-吡喃葡萄糖基乌苏烷 (11);三个甾体及其糖苷:b-谷甾醇 (12)、胡萝卜苷 (13)和(24R)-豆甾-4-烯-3-酮 (14);六个小分子化合物:对羟基苯甲酸 (15),咖啡酸 (16),香豆酸 (17),丁烯二酸 (18),3,5-二甲氧基-4-羟基苯甲酸(19),咖啡酸-4-O-β-D-吡喃葡萄糖苷(20);五个环烯醚萜类化合物:鸡矢藤苷 (21),鸡矢藤酸 (22),鸡矢藤酸甲酯 (23),saprosmoside E (24)和paederoside B (25)。其中化合物25未见文献报道,为新化合物。化合物1~8、11、14、15~20为首次从该化合物中分离得到。同时对鸡矢藤中环烯醚萜类化合物做了高效液相-串联质谱(HPLC-MSn)分析,探讨了这类化合物的质谱裂解规律。 第三章为黄芪多糖的提取工艺研究。首先确定了黄芪多糖含量的测定方法,并进行了方法学验证;其次探讨了黄芪中黄芪多糖的提取工艺,确定以酶法-Sevag法联用来去除黄芪多糖中的蛋白质,可使其提取物中黄芪多糖总含量达到70%以上。 第四章为近年来植物多糖的研究进展。主要包括植物多糖的提取纯化、多糖的定性定量检测方法、多糖的结构分析和多糖的药理活性。 This dissertation consists of four parts. The first and second parts reports the studies on the chemical constituents of medicinal plants of Picrorhiza Scrophulariiflora and Paederia scandens. The third part is about the extract technique of Astragalan Polysaccharide (APS). The last part reviews the progress of the studies on plant polysaccharides. The first chapter is about the chemical constituents of P. Scrophulariiflora which is widely used as an important medicine to treat various immune-related diseases. A new phenyl glycoside, scrophenoside D (1) and a new phenylethyl glycoside, scroside F (5), together with five known compounds, plantamajoside (2), plantainoside D (3), scroside A (4), 4-O-β-D-(6-O-vanilloylglucopyranosyl) vanillic acid (6); and methyl-p-coumarate (7) were isolated from the stems of P. scrophulariiflora. Their structures were elucidated by spectroscopic and chemical methods. The second chapter is about the chemical constituents of medicinal herb of P. scandens. Twenty-five compounds were isolated and purified by normal and reversed phase silica gel column chromatography. By physicochemical properties and spectral analysis, their structures were identified as rubiadin-1-methylether (1), isoscopoletin (2), 5-hydroxyl-8-methoxyl-coumarin (3), cleomiscosin B (4), cleomiscosin D (5), isolariciresinol (6), diadzein (7), linarin (8), oleanolic acid (9), ursolic acid (10), 3-O-β-D-glucopyranosyloxyl-ursane (11), b-sitosterol (12), b-daucosterol (13), (24R)-stigmast-4-ene-3-one (14), p-hydroxyl-benzoic acid (15), caffic acid (16), coumaric acid (17), trans-butenedioic acid (18), 3,5-dimethoxyl-4-hydroxylbenzoic acid (19), caffeic acid 4-O-β-D-glucopyranoside (20), paederoside (21), paederosidic acid (22), paederosidic acid methyl ester (23), saprosmoside E (24), paederoside B (25). Among them, compound 25 is a new compound. Compounds 1~8、11、14、15~20 were isolated from this plant for the first time. Futhermore, we studied the HPLC-MSn analysis and investigation of fragmentation behavior of the sulfur-containing iridoid glucosides. The third chapter is about the extracting process of Astragalan Polysaccharide (APS). The method of the content determination is built. The optimum condition of extraction of polysaccharides from Radix Astragali is defined and the more effective way to remove protein is combined enzyme method with Sevag method, by which the content of polysaccharides extract can be up to 70%. The last part is a review of the research progress of the plant polysaccharides, which includes its extraction, isolation, purification, determination, structure analysis, and pharmacology.
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活性筛选中发现尼泊尔水东哥 (Saurauia napaulensis DC.) 树皮95%乙醇提取物具有α-淀粉酶抑制活性、水麻(Debregeasia orientalis) 枝叶95%乙醇提取物显示血管紧张素转化酶(ACE)抑制活性、青荚叶(Helwingia japonica (Thunb.) Dieter.) 95%乙醇提取物的中小极性部分显示蛋白酪氨酸磷酸酯酶(PTP)1B抑制活性。为全面了解它们的成分及相关活性成份,主要运用硅胶柱层析方法从这三个植物分离得到39个化合物,通过波谱分析或与已知品对照的方法对其进行了鉴定。对木姜冬青(Ilex litseaefolia Hu et Tang)的成分做了进一步的研究,取得了如下结果。 1. 从尼泊尔水东哥树皮的95%乙醇提取物分离并鉴定12个化合物: auranamide、aurantiamide benzoate、齐墩果酸、β-谷甾醇、β-胡萝卜甙、乌苏酸、2α,3α-二羟基-12-烯-28-乌苏酸、2α,3β,24-三羟基-12-烯-28-乌苏酸、(2S,3S,4R,10E)-2-[(2'R)-2' -hydroxytetracosanoylamino] -10-octadecene -1,3,4-triol、 2α,3α,24-三羟基-12-烯-28-齐墩果酸、2α,3β-二羟基-12-烯-28-乌苏酸和2α,3α,24-三羟基-12-烯-28-乌苏酸。 2. 从水麻枝叶的95%乙醇提取物分离并鉴定了18个化合物:棕榈酸、二十烷酸、二十烷酸甲酯、β-谷甾醇、Monogynol A、桦木酸、Hederagenin、β-胡萝卜甙、18αH-19(29)-烯-3-酮-乌苏烷、3,4-开环-20(30)-烯-乌苏烷-3-酸、Pomolic acid,表儿茶素、儿茶素、槲皮素、槲皮素-3-O-β-D-吡喃葡萄糖苷、紫丁香苷、紫丁香酚苷和山萘酚-3-O-芸香糖。儿茶素、槲皮素和槲皮素-3-O-β-D-吡喃葡萄糖苷为具有ACE抑制活性的成分。 3. 从木姜冬青95%乙醇提取物的乙酸乙酯部分分离并鉴定了5个化合物: 2-O-β-D-吡喃葡萄糖-6,2´-二羟基-4,4´-二香草酰氧甲基-1,1´-二苯醚(冬青苷)和四个已知化合物:七叶内酯、香草酸、3,4-二甲氧基苯乙酸和vanilloylcalleryanin。冬青苷为新化合物。 4. 从青荚叶95%乙醇提取物的中小极性部分分离并鉴定了9个化合物:β-谷甾醇、β-胡萝卜苷、羽扇豆醇、桦木醇、桦木酸、棕榈酸甘油酯、桂皮酸、6αH-4-烯-3-酮-豆甾醇和6βH-4-烯-3-酮-豆甾醇。 5. 对1985-2006年间天然二苯醚类化合物及活性研究进展进行综述. The in vitro test indicated that the 95% ethanolic extract of the barks of Saurauia napaulensis DC showed α-amylase inhibitory activity, the 95% ethanolic extract of the whole plants of Debregeasia. orientalis showed angiotensin converting enzyme (ACE) inhibitory activity and some fractions of the 95% ethanolic extract of the aerial parts of Helwingia japonica showed protein tyrosine phosphatase (PTP)1B inhibitory activity. In order to investigate components and active compounds of the three plants, they were chemically studied mainly using. Thirty-nine compounds were isolated predominantly by column chromatography identified by spectral methods or comparing them with authentic samples. Further investigation of Ilex litseaefolia Hu et Tang was carried out. Major results are as follows: 1. Twelve compounds were isolation from the 95% ethanolic extract of the barks of S. napaulensis DC. They were identified as auranamide, aurantiamide benzoate, oleanolic acid, β-sitosterol, β-daucosterol, ursolic acid, 2α,3α-dihydroxyurs-12-en-28-oic acid, 2α,3β,24-trihydroxyurs-12-en-28-oic acid, (2S,3S,4R,10E)-2-[(2'R)-2'-hydroxytetracosanoyl amino]-10-octadecene-1,3,4-triol, 2α,3α,24 -trihydroxyolean-12-en-28-oic acid, 2α,3β-dihydroxyurs-12-en-28-oic acid, and 2α,3α,24-trihydroxyurs-12-ene-28-oic acid, respectively, by spectral methods or comparing them with authentic samples. 2. Eighteen compounds were isolation from the 95% ethanolic extract of the whole plants of D. orientalis. They were identified as palmitic acid, henicosanoic acid, henicosanoic acid methyl ester, β-sitosterol, monogynol, betulinic acid, hederagenin, β-daucosterol, 18αH-urs-20(30)-en-3-one, 3,4-seco-urs-20(30)-en-3-oic acid, pomolic acid, (-)-epicatechin, (+)-catechin, quercetin, quercetin 3-O-β-D-glucopyranoside, syringin, syringiaresinol digloside and kaempferol-3-O-rutinose. (+)-Catechin, quercetin and quercetin 3-O-β-D-glucopyranoside were the ACE inhibitory active components. 3. Further phytochemical investigation of the ethyl acetate parts of 95% ethanolic extract of the whole plant of I. litseaefolia afforded 2-O-β-D-glucopyranose-4,4´-di-vanilloyloxymethyl-2,6´-dihydroxy-1,1´-diphenyl ether (ilexiside), esculetin, vanillic acid, 3,4-dimethoxybenzylacetic acid and vanilloylcalleryanin. Ilexiside was new compound. 4. Nine compounds were isolation from the 95% ethanolic extract of the whole plant of H. japonica: β-sitosterol, β-daucosterol, lupeol, betulin, betulinic acid, glycerol monopalmitate, cinnamic acid, stignast-4-en-6β-3-one and stignast-4-en-6α-3-one 5.Diphenyl ether compounds from nature between 1985-2006 were summarized.
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花椒(Zanthoxylum piperitum)是川西干旱河谷地区的重要经济作物,化感作用是花椒连作障碍的原因之一。系统研究花椒化感作用有助于深入理解并最终解决花椒连作障碍。本文通过研究花椒叶、林下土壤浸提液及单一纯化感物质对花椒幼苗生长、苜蓿种子萌发及幼苗生长的影响作用,从生理生化角度揭示浸提液及纯化感物质的作用方式。通过室外和室内模拟实验,对浸提液及纯化感物质的化感效应进行比较,为花椒连作障碍的解决和化感作用机制的深入理解提供依据。主要结果如下: 1.花椒叶及林下土壤浸提液对地下生物量影响作用强与对地上生物量的化感效应,两种浸提液的化感效应强度不同,叶浸提液作用表现更显著。其中在Y6、Y8 、T6和T8处理时,花椒幼苗地下生物量分别降低了31.2%、32.1%、31.6%和31.7%。 2.两种浸提液均能显著影响花椒幼苗体内的保护性酶活性,总体说来,在高浓度下抑制各种抗氧化物酶活性,幼苗体内丙二醛含量增加,幼苗受害严重;在较低浓度下,各种保护性酶活性有所增加,丙二醛含量减少,幼苗伤害减轻。同时,不同月份里,各种酶的活性高低显著不同,9月份的活性显著低于7月份的酶活性。对于养分含量的影响,Y8、T8的影响强度最大,分别使碳元素含量降低了27.8%和30.8%,使钾元素含量降低了34.7%和25.6%。 3.花椒叶及林下土壤浸提液对苜蓿种子萌发及幼苗生长有化感作用,表现在最终萌发率、不同物质代谢及保护性酶活性的差异上。两种浸提液对苜蓿种子萌发过程中蛋白质的含量均无显著性影响,对淀粉和可溶性糖的影响作用类似,高浓度处理无明显化感效应,较低浓度处理显著降低二者在萌发苜蓿种子中的含量。Y2、Y4与T4处理分别使可溶性糖含量减少了32.3%、29.1%和18.8%,Y2与T2处理分别使淀粉含量降低了29.3%和26.8%。 4.苜蓿种子在4种单一化感物质最高浓度即10-3 mol•L-1处理下,萌发率显著降低,半数萌发时间推迟,随着处理浓度降低,抑制作用逐渐减弱,当降低到10-6 mol•L-1时,又能够表现出对苜蓿种子萌发的促进作用。 5.纯化感物质在10-6 mol•L-1时使苜蓿幼苗叶片的保护性酶活性显著升高,丙二醛含量显著降低;在10-3 mol•L-1时使苜蓿叶片中保护性酶活性显著降低,丙二醛含量增加,膜脂过氧化程度加重。 Zanthoxylum piperitum is one of the most important cash crops and has been extensively cultivated in Eastern Tibetan Plateau, especially in the fragile dry valley areas. Allelopathic effects could be a reason for Z. piperitum’s continuous cropping impediment. Systemmatically research of the effect of Z. piperitum allelopathy could help to comprehend the continuous cropping impediment. The allelopathic effects on seedlings growth and seed germination of aqueous extracts of Zanthoxylum piperitum and phenolic allelochemicals were studied, and the action mechanism of the two substances was also discussed from physiology. Indoor and outdoor experiments were set to compare the difference between aqueous extracts and pure allelochemicals. The main results showed that: 1. The aqueous extracts of leaf and soil had significant allelopathic effects on aboveground and underground biomass, but the effect on underground biomass was stronger than the effect on underground evidently. Treated with Y6、Y8 、T6 and T8, the underground biomass was reduced 31.2%、32.1%、31.6% and 31.7% respectively. 2. The activity of activities of superoxide dismutase, catalase, peroxidase and ascorbate peroxidase were significantly reduced, while the content of MDA was increased and the seedlings were suffered stronger, when treated by the high concentration; but at the low concentration, these were reversed. And then, at the different month, the activities of antioxidant enzyme were significantly distinct. As for the contents of nutrient element, Y8、T8 had the more intensive effects than other treatments. 3. The results showed that the two types of aqueous extracts had significant allelopathic effects on seed germination, substances metabolize and the activity of antioxidant enzyme. But the aqueous extracts had no effects on the content of protein, while had the similar effects on the content of starch and soluble sugar. At Y2、Y4 and T4, the content of soluble sugar decreased 32.3%、29.1% and 18.8% respectively. 4. Treated with 10-3 mol•L-1 of the four allelochemicals, the seed germination of alfalfa was significantly inhibited. Ferulic acid, coumarin and vanillic acid at 10-3 mol•L-1 significantly reduced the activities of antioxidant enzyme, while the content of MDA in alfalfa seedling was significantly increased. The restrain effects became weakened with the treat concentration falled. However, ferulic acid, coumarin and vanillic acid could increase the activities of antioxidant enzyme at 10-6mol•L-1.
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The commercial production of vanillin from sodium lignosulfonate under highly alkaline conditions, catalyzed by Cu2+ at elevated temperature and pressures up to 10 bar, has been simulated in a 3-L stirred reactor. Initially, the process was operated in the presence of nitrogen in dead-end mode, and it was shown that vanillin and vanillic acid were formed by hydrolysis at temperatures of 120, 140, and 160 °C. At the two higher temperatures, the amount of vanillin produced was the same. Subsequently, experiments were conducted at the same elevated pressures and temperatures with addition of air or oxygen-enriched air once the temperature in the reactor had reached temperatures similar to those used when only hydrolysis occurred. In this case, the concentration of vanillin at 140 and 160 °C was equal to that due to hydrolysis, and the subsequent 2-fold increase was due to oxidation. In addition, both vanillic acid and acetovanillone (which has rarely been reported) were produced, as was hydrogen. Thus, for the first time, it has been shown that the production of vanillin (and other compounds) from sodium lignosulfonate at elevated temperatures involves hydrolysis and oxidation, with hydrolysis starting at just above 100 °C, that is, much lower than has previously been reported. Approximately 50% is produced by each mechanism. In addition, the orders of the reactions of the different steps were estimated, and the reaction mechanisms are discussed.
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Os lenhosulfonatos representam um sub-produto formado durante o cozimento ao sulfito ácido, sendo queimados para a regeneração da base e recuperação de energia. No entanto, os lenhosulfonatos são também considerados uma importante matéria-prima para a produção de vários produtos de valor acrescentado. Os objectivos principais deste trabalho foram contribuir para uma melhor compreensão sobre a caracterização química e estrutural dos lenhosulfonatos do Eucalyptus globulus, assim como, para complementar a informação disponível sobre a síntese e a caracterização estrutural e térmica de materiais poliméricos obtidos a partir de compostos modelo dos produtos de oxidação dos lenhosulfonatos. O licor de cozimento ao sulfito foi analisado em termos do teor de cinzas, extractáveis, compostos voláteis, açúcares e lenhosulfonatos. O teor de cinzas e açúcares no licor de cozimento é muito elevado, tendo sido necessário purificar o mesmo (2,8-13,8 % e 3,2-9,1 %, respectivamente). A análise dos açúcares mostrou uma quantidade considerável de pentoses, sendo o açúcar predominante a xilose. Os lenhosulfonatos foram purificados, isolados e caracterizados por química molhada (titulação potenciométrica e oxidação com permanganato), análise elementar, espectroscopia de ultravioleta/visível (UV/Vis), espectroscopia de infravermelho de transformada de Fourier (FTIR), espectroscopia de ressonância magnética nuclear de protão (RMN de 1H) e carbono (RMN de 13C), espectrometria de massa de ionização por electrospray (ESI-MS), cromatografia de permeação em gel (GPC), termogavimetria (TGA) e calorimetria diferencial de varrimento (DSC). Os lenhosulfonatos são constituídos principalmente por unidades S, são parcialmente sulfonados e possuem um peso molecular relativamente baixo (Mw = 1250-2400 Da). A ruptura das ligações β-O-4 e α-O-4 da lenhina do Eucalyptus globulus após cozimento ao sulfito ácido originam olígomeros de baixo peso molecular cuja estrutura foi elucidada por RMN 1D/2D e ESI-MS. A degradação térmica dos lenhosulfonatos apresentou dois máximos de degradação a 188-190ºC e a 315-380ºC. As curvas de DSC mostraram um pico endotérmico para temperaturas inferiores a 130ºC e um pico exotérmico a 300-500ºC. Os lenhosulfonatos foram despolimerizados na presença de oxigénio molecular em meio alcalino. Os produtos de oxidação principais foram o aldeído siríngico, a vanilina, o ácido vanílico e o ácido siríngico. A adição do catalisador (sal de cobre) promoveu a oxidação dos lenhosulfonatos aumentando o rendimento dos aldeídos aromáticos (< 50%). A presença de açúcares nos lenhosulfonatos teve um efeito negativo no rendimento dos produtos de oxidação principais. Alguns compostos modelo dos produtos de oxidação dos lenhosulfonatos foram polimerizados por poliadição (catiónica e radicalar) e policondensação. Os monómeros e os polímeros foram caracterizados por espectroscopia de infravermelho de transformada de Fourier e reflectância total atenuada (FTIR-ATR), RMN em solução e no estado sólido, UV/Vis no estado sólido, GPC, difracção de raios-X (XRD), TGA e DSC. Os compostos modelo estudados foram os estirenos metoxi-substituídos (p-metoxiestireno e 3,4-dimetoxiestireno) e os ácidos hidroxi aromáticos metoxi-substituídos (ácido vanílico e ácido siríngico). O 3,4-dimetoxiestireno foi ainda copolimerizado com o éter isobutil vinílico e os seus copolímeros foram desmetilados, assim como, o poli(p-metoxiestireno) e o poli(3,4-dimetoxiestireno). A polimerização catiónica do p-metoxiestireno e 3,4-dimetoxiestireno é mais rápida e mais completa do que a polimerização radicalar produzindo polímeros com pesos moleculares elevados. O poli(p-metoxiestireno) (Mw = 235000 Da) possui um peso molecular maior do que o poli(3,4-dimetoxiestireno) (Mw = 18800 Da). A estabilidade térmica e a temperatura de transição vítrea diminuiram com a presença do segundo grupo metoxilo. A desmetilação dos homopolímeros foi bem sucedida, tendo sido corroborada por FTIR-ATR e RMN. A policondensação do ácido siríngico foi dificultada pela presença do segundo grupo metoxilo, tendo sido necessário adicionar uma maior quantidade do agente de condensação devido a factores estéricos. O poli(ácido vanílico) e poli(ácido siríngico) são insolúveis na maior parte dos solventes orgânicos, sendo parcialmente solúveis em clorofórmio, ácido triflúoracético, 1,1,2,2- tetracloroetano, dimetilsulfóxido, tetrahidrofurano, N,N’-dimetilformamida e 1,1,1,3,3,3-hexaflúor-2-propanol. A estabilidade térmica diminuiu com a presença do segundo grupo metoxilo e os dois polímeros não exibiram temperatura de transição vítrea. O poli(ácido vanílico) e poli(ácido siríngico) apresentaram uma estrutura muito cristalina (grau de cristalinidade 70% e 50%, respectivamente). O segundo grupo metoxilo aumentou o valor da absorvância, mas a forma do espectro de UV/Vis foi similar. A polimerização catiónica do éter isobutil vinílico resultou na produção de um polímero muito viscoso com peso molecular elevado (Mw = 20400 Da). A degradação térmica do polímero ocorreu em várias gamas de temperatura e foi completa (0% de resíduo a 800ºC). A copolimerização catiónica do 3,4-dimetoxiestireno com o éter isobutil vinílico foi realizada com proporções diferentes 80:20, 50:50 e 20:80. Os copolímeros apresentaram uma viscosidade elevada e um peso molecular baixo (Mw = 2000-4000 Da) que aumentou com a quantidade de éter isobutil vinílico. A degradação térmica dos copolímeros ocorreu também em várias gamas de temperatura, sendo a sua degradação completa (0,9-1,5% de resíduo a 800ºC). A desmetilação dos copolímeros não foi bem sucedida, tendo sido confirmada por FTIR-ATR e RMN.
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The sugar beet cyst nematode, Heterodera schachtii, is a major agricultural pest. The disruption of the mating behaviour of this plant parasite in the field may provide a means of biological control, and a subsequent increase in crop yield. The H. schachtii female sex pheromone, which attracts homospecific males, was collected in an aqueous medium and isolated using high performance liquid chromatography. Characterization of the male-attractive material revealed that it was heat stable and water soluble. The aqueous medium conditioned by female H. schachtii was found to be biologically active and stimulated male behaviour in a concentration dependent manner. The activity of the crude pheromone was specific to males of H. schachtii and did not attract second stage juveniles. Results indicated that vanillic acid, a putative nematode pheromone, is not an active component of the H. schachtii sex pheromone. Male H. schachtii exhibited stylet thrusting, a poorly understood behaviour of the male, upon exposure to the female sex pheromone. This behaviour appeared to be associated with mate-finding and was used as a novel indicator of biological activity in bioassays. Serotonin, thought to be involved in the neural control of copulatory behaviour in nematodes, stimulated stylet thrusting. However, the relationship between stylet thrusting induced by the sex pheromone and stylet thrusting induced by serotonin is not clear. Extracellular electrical activity was recorded fi-om the anterior region of H. schachtii males during stylet thrusting, and appeared to be associated with this behaviour. The isolation of the female sex pheromone of H. schachtii may, ultimately, lead to the structural identification and synthesis of the active substance for use in a novel biological control strategy.
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This study investigated the separate and combined anthelmintic (AH) effects of different phenolic compounds, including condensed tannins and flavonoids, all of which are known to occur in willow leaves, a potentially valuable dry season feed. A range of contrasting model tannins, which span the whole range of willow tannins, were isolated from tilia flowers, goat willow leaves, black currant leaves and red currant leaves. All together, the tested compounds represented the major tannin types (procyanidins and prodelphinidins) and flavonoid types (flavonols, flavones and flavanones). The larval exsheathment inhibition assay (LEIA) was used to assess their in vitro effects on Haemonchus contortus third stage larvae. Arbutin, vanillic acid, and taxifolin proved to be ineffective whereas naringenin, quercetin and luteolin were highly effective at 250 μM concentrations. Procyanidin (PC) tannins tended to be less active than prodelphinidin tannins (PD). Experiments with combinations of tannins and quercetin or luteolin revealed for the first time the existence of synergistic AH effects between tannins and flavonoid monomers. They also provided evidence that synergistic effects appear to occur at slightly lower concentrations of PC than PD. This suggests that the AH activity of condensed tannins can be significantly enhanced by the addition of quercetin or luteolin. This information may prove useful for plant breeding or selection and for designing optimal feed mixtures.
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This paper describes the preparation of a biomimetic Langmuir-Blodgett film of tyrosinase incorporated in a lipidic layer and the use of lutetium bisphthalocyanine as an electron mediator for the voltammetric detection of phenol derivatives, which include one monophenol (vanillic acid), two diphenols (catechol and caffeic acid) and two triphenols (gallic acid and pyrogallol). The first redox process of the voltammetric responses is associated with the reduction of the enzymatically formed o-quinone and is favoured by the lutetium bisphthalocyanine because significant signal amplification is observed, while the second is associated with the electrochemical oxidation of the antioxidant and occurs at lower potentials in the presence of an electron mediator. The biosensor shows low detection limit (1.98 x 10(-6)-27.49 x 10(-6) M), good reproducibility, and high affinity to antioxidants (Km in the range of 62.31-144.87 mu M). The excellent functionality of the enzyme obtained using a biomimetic immobilisation method, the selectivity afforded by enzyme catalysis, the signal enhancement caused by the lutetium bisphthalocyanine mediator and the increased selectivity of the curves due to the occurrence of two redox processes make these sensors exceptionally suitable for the detection of phenolic compounds. (C) 2010 Elsevier B.V. All rights reserved.
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In this work, the separation of nine phenolic acids (benzoic, caffeic, chlorogenic, p-coumaric, ferulic, gallic, protocatechuic, syringic, and vanillic acid) was approached by a 32 factorial design in electrolytes consisting of sodium tetraborate buffer(STB) in the concentration range of 10-50 mmol L(-1) and methanol in the volume percentage of 5-20%. Derringer`s desirability functions combined globally were tested as response functions. An optimal electrolyte composed by 50 mmol L(-1) tetraborate buffer at pH 9.2, and 7.5% (v/v) methanol allowed baseline resolution of all phenolic acids under investigation in less than 15 min. In order to promote sample clean up, to preconcentrate the phenolic fraction and to release esterified phenolic acids from the fruit matrix, elaborate liquid-liquid extraction procedures followed by alkaline hydrolysis were performed. The proposed methodology was fully validated (linearity from 10.0 to 100 mu g mL(-1), R(2) > 0.999: LOD and LOQ from 1.32 to 3.80 mu g mL(-1) and from 4.01 to 11.5 mu g mL(-1), respectively; intra-day precision better than 2.8% CV for migration time and 5.4% CV for peak area; inter-day precision better than 4.8% CV for migration time and 4.8-11% CV for peak area: recoveries from 81% to 115%) and applied successfully to the evaluation of phenolic contents of abiu-roxo (Chrysophyllum caimito), wild mulberry growing in Brazil (Morus nigra L.) and tree tomato (Cyphomandra betacea). Values in the range of 1.50-47.3 mu g g(-1) were found, with smaller amounts occurring as free phenolic acids. (C) 2009 Elsevier B.V. All rights reserved.
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A total of 25 sugarcane spirit extracts of six different Brazilian woods and oak, commonly used by cooperage industries for aging cachaca, were analyzed for the presence of 14 phenolic compounds (ellagic acid, gallic acid, vanillin, syringaldehyde, synapaldehyde, coniferaldehyde, vanillic acid, syringic acid, quercetin, trans-resveratrol, catechin, epicatechin, eugenol, and myricetin) and two coumarins (scopoletin and coumarin) by HPLC-DAD-fluorescence and HPLC-ESI-MS(n). Furthermore, an HPLC-DAD chromatographic fingerprint was build-up using chemometric analysis based on the chromatographic elution profiles of the extracts monitored at 280 nm. Major components identified and quantified in Brazilian wood extracts were coumarin, ellagic acid, and catechin, whereas oak extracts shown a major contribution of catechin, vanillic acid, and syringaldehyde. The main difference observed among oak and Brazilian woods remains in the concentration of coumarin, catechin, syringaldehyde, and coniferaldehyde. The chemometric analysis of the quantitative profile of the 14 phenolic compounds and two coumarins in the wood extracts provides a differentiation between the Brazilian wood and oak extracts. The chromatographic fingerprint treated by multivariate analysis revealed significant differences among Brazilian woods themselves and oak, clearly defining six groups of wood extracts: (i) oak extracts, (ii) jatoba extracts, (iii) cabreuva-parda extracts, (iv) amendoim extracts, (v) canela-sassafras extracts and (vi) pequi extracts.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)