紫珠的松香烷型二萜成分研究

从紫殊全草的乙醇提取物的氯仿部分中分得5个松香烷型二萜,经光谱数据分别鉴定为脱氢枞酸(1)、7β-羟基-脱氢枞酸(2)、7α-羟基-脱氢枞酸(3)、7-羰基-脱氢枞酸(4)和18-羧基-6,8,11,13-松香烷酸。以上化台物均为首次从该植物中分得。     

云南脂松香制备光学纯去氢枞酸的研究

以松节油作反应溶剂,在硫、碘的催化作用下云南脂松香经催化异构化、脱氢成为脱氢松香酸,通过进一步的提取、纯化等步骤可直接得到纯度高达96%以上的光学纯的去氢枞酸,其收率为26.6g/100g(松香)。     

去氢枞酸结构修饰与生物活性研究的新进展

去氢枞酸是一种天然三环二萜树脂酸,具有抗炎、抗菌、抗肿瘤、抗病毒等多种生物活性。为了寻找潜在的生物活性化合物,对其骨架结构修饰开展了大量的研究工作,本文对去氢枞酸近年来结构修饰及生物活性的研究进行总结,旨在为去氢枞酸的深入研究提供参考。     

无溶剂一锅法合成N-歧化松香基-1,4-二氢吡啶

歧化松香胺、醛和1,3-二羰基化合物在80℃发生Hantzsch反应,以68%~85%的产率得到一系列1,4-二氢吡啶类衍生物。通过IR、MS、1H NMR和元素分析对产物进行了结构表征。     

基于计算机模拟技术分析去氢枞酸作为PI3K/AKT/mTOR信号通路抑制剂的潜力

为了研究去氢枞酸对PI3K/AKT/mTOR信号通路的抑制能力,本研究利用分子对接技术预测去氢枞酸对通路蛋白的结合能力和结合方式,用蛋白免疫印迹技术验证通路蛋白受抑制程度,用网络服务器进行类药性与药代动力学的模拟.预测结果发现,去氢枞酸对通路蛋白具有一定的结合能力,预测构像的最低结合能最高为-6.16 kcal/mol...     

天然辣椒素酯的酶促合成与生物活性

研究了天然辣椒素经化学．酶法转化为天然辣椒素酯类物质的方法。在30℃,香草醇、脂肪酸酯分别为50、75mmol／L的100mL脱水丙酮溶液,以1g固定化的脂肪酶Novozyme435为催化剂,摇床转速为200r／min条件下反应24h,目标化合物产率可达63％。经硅胶柱色谱分离纯化后,所得产物经质谱确证其含有天然辣椒素酯（capsiate）、二氢辣椒素酯（dihydrocapsiate）、降二氢辣椒素酯（nordihydrocapsiate）、高二氢辣椒素酯（homodi-hydrocapsiate）等。制备HPLC分离后得到辣椒素酯和二氢辣椒素酯,以^1HNMR及MS确定结构。活性测试表明辣椒素酯类物质具有激活PPARγ的生物活性及体外抑制乳腺癌细胞（MCF-7）和肝癌细胞（HepG2）的活性。     

高等植物叶绿素生物合成的联乙烯还原酶及编码基因研究进展

联乙烯还原酶(DVR)将各种叶绿素中间物质的8-乙烯基转化为乙基,是叶绿素生物合成必不可少的一个关键酶。迄今已在高等植物中检测到5种DVR活性。水稻和玉米的重组DVR蛋白能将联乙烯叶绿素a、叶绿素酸酯a、原叶绿素酸酯a、镁原卟啉Ⅸ单甲酯和镁原卟啉Ⅸ分别转化为相应的单乙烯物质,从而证实了这5种DVR活性。在高等植物中各种DVR活性是由一个基因编码的具有广谱底物专化性的DVR蛋白所催化,但来源于不同物种的DVR蛋白的催化活性可能具有极显著的差异,并且即使是同一个DVR蛋白,对不同的联乙烯底物也可能具有显著不同的催化活性。在此基础上,提出了"源于一个联乙烯还原酶的叶绿素生物合成多分支路径"假说。该文对近年来国内外有关高等植物叶绿素生物合成途径中联乙烯中间物质与联乙烯还原酶活性、联乙烯还原酶基因的克隆及重组酶活性检测、联乙烯还原酶的数目与叶绿素生物合成的多分支路径等方面的研究进展进行综述,并讨论了有待进一步探讨的若干问题。     

CN101629087 用松香生产及其深加工残渣制备生物质燃料油的方法

本发明提供了一种用松香生产及其深加工残渣制备生物质燃料油的方法,松香生产及其深加工利用过程中形成的固体残渣,其中虽然仍然含有少量松香树脂酸但含量很低,主要含有氧化松香树脂酸、聚合树脂酸、树脂酸酯、难于皂化甚至不能皂化的中性物质等,在活性白土、硅藻土、高岭土、分子筛等催化剂作用下进行催化裂解反应,从而制备得到生物质燃料油。     

杭白菊的化学成分研究：两个新三萜酯的结构测定

从杭白菊(Dendranthema morifolium (Ramat. )Tzvel.)的乙醚部分分离出13个化合物。运用波谱技术和化学方法证明其中2个为新化合物,命名为棕榈酸16β,22α-二羟基假蒲公英甾醇酯(1)和棕榈酸16β,28-二羟基羽扇醇酯(2)。     

二氢杨梅素硬脂酸酯的合成及其抗油脂氧化特性研究

二氢杨梅素是药食两用植物———藤茶中的主体活性成分,具有很好的水溶性抗氧化作用,但其难溶于油的特性限制了其在油脂上的应用。本研究通过对其化学修饰,制备了既能溶于油脂又具有较好抗氧化作用的二氢杨梅素硬脂酸酯。     

Degradation of vinyl acetate by soil, sewage, sludge, and the newly isolated aerobic bacterium V2

Vinyl acetate is subject to microbial degradation in the environment and by pure cultures. It was hydrolyzed by samples of soil, sludge, and sewage at rates of up to 6.38 and 1 mmol/h per g (dry weight) under aerobic and anaerobic conditions, respectively. Four yeasts and thirteen bacteria that feed aerobically on vinyl acetate were isolated. The pathway of vinyl acetate degradation was studied in bacterium V2. Vinyl acetate was degraded to acetate as follows: vinyl acetate + NAD(P)+----2 acetate + NAD(P)H + H+. The acetate was then converted to acetyl coenzyme A and oxidized through the tricarboxylic acid cycle and the glyoxylate bypass. The key enzyme of the pathway is vinyl acetate esterase, which hydrolyzed the ester to acetate and vinyl alcohol. The latter isomerized spontaneously to acetaldehyde and was then converted to acetate. The acetaldehyde was disproportionated into ethanol and acetate. The enzymes involved in the metabolism of vinyl acetate were studied in extracts. Vinyl acetate esterase (Km = 6.13 mM) was also active with indoxyl acetate (Km = 0.98 mM), providing the basis for a convenient spectrophotometric test. Substrates of aldehyde dehydrogenase were formaldehyde, acetaldehyde, propionaldehyde, and butyraldehyde. The enzyme was equally active with NAD+ or NADP+. Alcohol dehydrogenase was active with ethanol (Km = 0.24 mM), 1-propanol (Km = 0.34 mM), and 1-butanol (Km = 0.16 mM) and was linked to NAD+. The molecular sizes of aldehyde dehydrogenase and alcohol dehydrogenase were 145 and 215 kilodaltons, respectively.     

Degradation of vinyl acetate by soil, sewage, sludge, and the newly isolated aerobic bacterium V2.

Vinyl acetate is subject to microbial degradation in the environment and by pure cultures. It was hydrolyzed by samples of soil, sludge, and sewage at rates of up to 6.38 and 1 mmol/h per g (dry weight) under aerobic and anaerobic conditions, respectively. Four yeasts and thirteen bacteria that feed aerobically on vinyl acetate were isolated. The pathway of vinyl acetate degradation was studied in bacterium V2. Vinyl acetate was degraded to acetate as follows: vinyl acetate + NAD(P)+----2 acetate + NAD(P)H + H+. The acetate was then converted to acetyl coenzyme A and oxidized through the tricarboxylic acid cycle and the glyoxylate bypass. The key enzyme of the pathway is vinyl acetate esterase, which hydrolyzed the ester to acetate and vinyl alcohol. The latter isomerized spontaneously to acetaldehyde and was then converted to acetate. The acetaldehyde was disproportionated into ethanol and acetate. The enzymes involved in the metabolism of vinyl acetate were studied in extracts. Vinyl acetate esterase (Km = 6.13 mM) was also active with indoxyl acetate (Km = 0.98 mM), providing the basis for a convenient spectrophotometric test. Substrates of aldehyde dehydrogenase were formaldehyde, acetaldehyde, propionaldehyde, and butyraldehyde. The enzyme was equally active with NAD+ or NADP+. Alcohol dehydrogenase was active with ethanol (Km = 0.24 mM), 1-propanol (Km = 0.34 mM), and 1-butanol (Km = 0.16 mM) and was linked to NAD+. The molecular sizes of aldehyde dehydrogenase and alcohol dehydrogenase were 145 and 215 kilodaltons, respectively.     

Selective inhibition of Src SH2 by a novel thiol-targeting tricarbonyl-modified inhibitor and mechanistic analysis by (1)H/(13)C NMR spectroscopy.

Detailed analysis of Src SH2 binding by peptides containing a novel tricarbonyl-modified pTyr moiety is described. We envisaged that Src SH2 selectivity might be obtained by exploiting the thiol group of Cys188 present in the pTyr binding pocket of the protein at the betaC3 position. Peptidyl as well as non-peptidyl compounds 1-4 possessing a 4-alpha,beta-diketoester-modified pTyr mimic exhibited micromolar affinity to Src SH2. Furthermore, these tricarbonyl compounds were selective for Src SH2 to the extent they showed no significant affinity for either Cys188Ser or Cys188Ala Src SH2 mutants. Upon closer examination of the binding of these tricarbonyls to Src SH2 using NMR of 13C-labeled compounds (6a, 6b, and 6c), we found that after the initial binding event the molecule disproportionated in a 'retro-Claisen' fashion to provide benzoic acid 16 and, following hydrolysis of the methyl ester 17, the hemiketal adduct of glyoxalic acid 18.     

Enzymatic synthesis of arbutin undecylenic acid ester and its inhibitory effect on melanin synthesis

Transesterification of arbutin and undecylenic acid vinyl ester was catalyzed by alkaline protease, Bioprase, in dimethylformamide to get arbutin derivative having undecylenic acid at 6-position of glucose moiety, 6-O-undecylenoyl p-hydroxyphenyl beta-D-glucopyranoside. The reaction rate increased with increase of arbutin concentration, and when its concentration was 0.9 M, the conversion rate was more than 90% under addition of 2 M undecylenic acid vinyl ester. The obtained arbutin ester significantly suppressed melanin production in murine B16 melanoma cells.     

红花锦鸡儿中苯丙素类化合物的研究

对红花锦鸡儿Caragana rosea Turcz ex Maxim的地上部分进行化学成分研究.从乙醇提取物的氯仿可溶部位分离获得9个苯丙素类化合物.根据理化性质和各种波谱(UV、IR、MS、1D和2DNMR)分析,鉴定其结构分别为肉桂酸、5个木脂素(±)落叶松脂素、(±)-5,5'-二甲氧基-落叶松脂素、(±)-lyoniresinol、(±)-松脂素、(±)-丁香脂素和三个倍半木脂素(±)-ficusesquilignan A、(±)-buddlenol C、(±)-buddlenol D.所有的化合物均为首次从该植物中分离得到.     

A new process for the esterification of wood by reaction with vinyl esters

A novel route to wood modification by transesterification of vinyl esters is developed in the current study. The reaction between varied saturated and unsaturated vinyl esters and the hydroxyl groups of maritime pine sapwood (Pinus pinaster Soland) was examined using potassium carbonate as a catalyst. The esterification of wood was investigated by weight percent gain calculations (WPG), Fourier-transform infrared spectroscopy (FTIR) and ¹³C cross-polarization with magic-angle spinning nuclear magnetic resonance spectroscopy (¹³C CP–MAS NMR). Differences in the rates of modification were noted, depending on the vinyl ester used, but relatively high yields were obtained in all cases. The infrared and NMR spectra of the different esterified samples were analysed in detail and the assignment of the signals corresponding to the grafted acyl groups confirmed that esterification occurred.     

Synthesis of fructose esters by Pseudomonas sp. lipase in anhydrous pyridine

Fructose esters were synthesized from fructose and vinyl esters by transesterification catalyzed by lipase AK in anhydrous pyridine. The efficacy of ester synthesis was enhanced by increasing the length of carbon chain in the vinyl ester. Fructose monoesters and diesters were synthesized and their relative production ratio depended on the chain length of vinyl esters. Vinyl esters with chain length longer than C10 produced only monoacyl fructose which has an acyl moiety attached to C1 carbon of fructose. The monoacyl fructose composed of fatty acid with C10 or longer chains had a strong emulsifying activity on various hydrocarbons and oils.     

Enzymatic synthesis of lysophosphatidic acid and phosphatidic acid

Immobilised 1,3-specific lipase from Rhizopus arrhizus was used as catalyst for the esterification of -glycero-3-phosphate and fatty acid or fatty acid vinyl ester in a solvent-free system. With lauric acid vinyl ester as acyl donor, a_w<0.53 favored the synthesis of lysophosphatidic acid (1-acyl-rac-glycero-3-phosphate, LPA1) and the spontaneous acyl migration of the fatty acid on the molecule. Subsequent acylation by the enzyme resulted in high phosphatidic acid (1,2-diacyl-rac-glycero-3-phosphate, PA) formation and high total conversions (>95%). With oleic acid, maximum conversions of 55% were obtained at low water activities. Temperatures below melting point of the product favored precipitation and resulted in high final conversion and high product ratio [LPA/(PA+LPA)]. Thus, LPA was the only product with lauric acid vinyl ester as acyl donor at 25°C. Increased substrate ratio ( -glycero-3-phosphate/fatty acid) from 0.05 to 1 resulted in a higher ratio of LPA to PA formed, but a lower total conversion of -glycero-3-phosphate. Increased amounts of enzyme preparation did not result in higher esterification rates, probably due to high mass-transfer limitations.     

溴化马来松香的合成、表征及其阻燃性的研究

本文以马来松香与液溴加成,合成了溴化马来松香;研究了反应温度、原料的摩尔比、反应时间等因素对反应过程及产物性能的影响.用FT-IR、1H NMR和TG对溴化马来松香进行了表征.结果表明,当反应温度为-2～6℃,反应时间5～6 h,反应物的当量配比约为1.2时,收率可达87.9%.溴化马来松香具有较好的阻燃性,同时也拓宽了松香的应用范围,提高了松香的附加值.     

Regioselective synthesis of cyclodextrin mono-substituted conjugates of non-steroidal anti-inflammatory drugs at C-2 secondary hydroxyl by protease in non-aqueous media

Three beta-cyclodextrin (beta-CD) conjugates of non-steroidal anti-inflammatory drugs were synthesized by enzymatic methods. Transesterification of beta-CD with vinyl ester of indomethacin, ketoprofen and etodolac was performed by the catalysis of alkaline protease from Bacillus subtilis in anhydrous DMF for 3 days. The drug molecules were selectively conjugated onto one of the secondary hydroxyl groups of beta-CD through ester-linkage to improve their poor water solubility and absorption characteristics. The products were characterized by ESI-MS, (1)H NMR and (13)C NMR. The structures of products with monoacylation occurring at the C-2 secondary hydroxyl groups of beta-CD were confirmed.