野生和人工栽培漆树液多糖的分子结构与生物活性

从湖北毛坝野生(大木)和人工栽培(小木)漆树液中分离纯化出酸性杂多糖D-LP和X-LP,化学降解和光谱分析表明两种多糖均含有D-Gal、D-GlcA、L-Ara和L-Rha,其摩尔比分别为77:18.3:3.7:1和63.7:13.3:3.9:1.两种漆多糖都是以β(1→3)D-Gal为主链的高度支化酸性杂多糖.D-LP支化度较高,分支点在Gal的C₆和C₄位;而X-LP仅有部分主链D-Gal的C₆位发生支化.小鼠腹腔注射试验表明,两种漆多糖均具有明显的免疫抑制作用,同时由野生漆树液提取的D-LP显示出比X-LP更高的免疫抑制功能和升白细胞活性功能.     

醇水介质中漆酶催化氧化漆酚及其类似物

本文作者在醇水介质中对漆酚及其类似物的酶催化氧化反应进行了研究。探讨了混合溶剂中漆酶的行为。结果发现邻苯二酚被烷基取代后更有利于漆酶的催化氧化。反应可能经过两个步骤,先是底物氧化生成黄色苯醌类物质,然后醌类中间物偶联形成多聚酚。     

生漆的生物学活性与结构修饰研究进展

生漆是从漆树皮层采割的天然树脂,主要由漆酚、漆多糖、漆酶等化合物组成。漆多糖是一种酸性杂多糖,具有抗原性、抗肿瘤、抗凝血等生物学功能。漆酶被广泛应用于食品、医药和工业等领域;它有氧条件下可催化多酚、多氨基苯等物质,使之生成相应的苯醌和水。漆酚是一种多酚类化合物,对微生物具有广谱抗菌、抑菌作用,且能抑制肿瘤细胞活性、核转录因子-kB(NF-kB)活性,也具有抗艾滋病毒、抗氧化、降低胆固醇以及甘油三酯等功效;通过对漆酚化合物的结构修饰,制备具有各各不同性能特点的生物基高分子材料,诸如漆酚缩醛树脂、漆酚元素有机化合物以及纳米粒子、分子筛等等,为高值化利用生漆资源,提升漆树的经济价值提供了新途径。     

杂原子掺杂的素馨烯与Li+@C60之间弱相互作用的理论研究

采用密度泛函M06-2X方法,对C₆₀和包裹了Li⁺的C₆₀与巴氏碗(素馨烯)及其同系物的弱相互作用进行了系统的研究.在优化的几何构型基础上,对4种化合物进行了前线分子轨道成分分析;在考虑基组重叠误差下,对相互作用能进行分析,并利用约化梯度模型得到了它们的约化梯度密度散点图.结果表明4种化合物的弱相互作用强弱顺序为：C₁₈O₃H₆/Li⁺@C₆₀21H₁₂@C₆₀18N₃H₆/Li⁺@C₆₀21H₁₂/Li⁺@C₆₀.巴氏碗碗沿的—CH₂基团被—NH和O原子取代后,掺杂了杂原子的素馨烯导致分子间的静电相...     

有玻璃态和液晶态的胆甾烯基苯并菲的合成及介晶性

将盘状液晶基元苯并菲与手性向列型液晶基元胆甾烯基结合的化合物, 可望出现全新的性质. 合成了含有胆甾烯基的苯并菲化合物C₁₈H₆(OC₅H₁₁)₅(OC₅H₁₀COOCh) (2), 2,7-C₁₈H₆(OC₅H₁₁)₄(OC₅H₁₀COOCh)₂ (4), C₁₈H₆(OR)₃(OC_nH_{2nCOO- Ch)3 (R＝C5H11, C7H15, C9H19, C11H23, n＝1, 5, 10) (6a～6f), C18H6(OC5H10COOCh)6 (Ch: cholesteryl) (8). 偏光显微镜和差示扫描量热法对这些化合物的热致介晶性研究结果显示, 化合物 4, 6a～6e具有手性盘状向列相和玻璃态, 8呈现近晶B相(SB)和玻璃态. 随间隔基长度n和烷基链R碳原子数的增加, 化合物玻璃化温度和清亮点呈下降趋势. 随着胆甾烯基数目减少, 化合物的玻璃化温度和清亮点降低.}     

2D-NMR研究中国生漆漆酚结构

用离心旋转薄层层析法在涂渍AgNO₃的硅胶板上成功地分离了乙酰化漆酚。对其主要组分(64.6%),用¹H、¹³C常规谱,DEPT编辑谱,同核、异核化学位移相关二维谱,二维J谱,异核中继相干传递二维谱及弛豫时间T₁等,确定了此化合物的结构与构型和¹H、¹³C谱线归属。实验证明漆酚中此组分是3-十五碳烯烃(8′Z、11′E、13′Z)邻苯二酚,异核中继相干传递二维谱新技术能有效地应用于复杂未知化合物的结构测定。     

含有酯基及酰胺基柔链的苯并菲盘状液晶的合成、分子间氢键对柱状介晶性的影响

合成了三个系列, 共二十四个有两种不同软链的对称和非对称苯并菲盘状液晶化合物, C₁₈H₆(OR)₃- (OCH₂COOEt)₃, C₁₈H₆(OR)₃(OCH₂COOBu)₃, C₁₈H₆(OR)₃(OCH₂CONHBu)₃, 其中R＝C₅H₁₁, C₆H₁₃, C₇H₁₅, C₈H₁₇. 化合物通过柱层析纯化, 结构通过¹H NMR, IR, 元素分析等确证. 化合物热稳定性通过TGA测定, 并显示出较高的热稳定性. 通过偏光显微镜和差视扫描量热法对这些化合物的热致液晶性进行了研究. 结果显示: 对于苯并菲液晶化合物C₁₈H₆(OR)₃(OCH₂COOEt)₃, 非对称性化合物较之对称异构体化合物有更低的熔点和更高的清亮点, 因而非对称性化合物有更宽的介晶温度范围. 对于分子中含有酰胺基的苯并菲液晶化合物C₁₈H₆(OR)₃(OCH₂CONHBu)₃, 对称化合物有比非对称异构体更高的清亮点和更有序的六方柱状介晶相, 且其与具有同样软链长度的分子中不含酰胺基的化合物系列C₁₈H₆(OR)₃(OCH₂COOBu)₃相比较, 由于柱内分子间氢键的形成, 不仅有更高的熔点和清亮点, 而且有更丰富的柱状介晶相.     

相变贮热材料四氯合钴酸铵共析物的制备和热性能

在温度353 K的乙醇溶液中, 采用热回流法合成了热致相变化合物四氯合钴酸铵(1-C_nH_2n+1NH₃)₂CoCl₄(n=10, 18)(分别简写为C₁₀Co、C₁₈Co)及其二元混合物. 利用差示扫描量热和X射线法对二元体系进行了表征.根据测定实验数据构筑二元相图, 所得相图结果表明, 在w_C10Co=52.51% (质量分数)处存在中间化合物(1-C₁₀H₂₁NH₃)(1-C₁₈H₃₇NH₃)CoCl₄. 相图还包括两个三相线, 相对应的两个共析温度分别为(347±1)和(343±1) K, 共析点分别在w_C10Co=38.50%和w_C10Co=69.86%处. 并且, 在相图的左右边界存在端际固溶体(α、β)及中间区域存在非化学计量相(γ). 四氯合钴酸铵及其二元混合体系作为相变材料贮热时, 相变温度范围为340-370 K, 相变焓大小范围在2.13到141.12 J·g^-1之间.     

钒取代的Dawson型磷钼酸对酪氨酸酶的抑制作用

采用酶动力学方法研究了5种钒取代的Dawson型磷钼酸H₇[P₂Mo₁₇VO₆₂]、H₈[P₂Mo₁₆V₂O₆₂]、H₉[P₂Mo₁₅V₃O₆₂]、H₈[P₂Mo₁₄V₄O₆₂H₂]和H₉[P₂Mo₁₃V₅O₆₂H₂](分别简写为P₂Mo₁₇V、P₂Mo₁₆V₂、P₂Mo₁₅V₃、P₂Mo₁₄V₄和P₂Mo₁₃V₅)对蘑菇酪氨酸酶二酚酶的抑制作用,结果表明,效应物P₂Mo₁₇V、P₂Mo₁₆V₂和P₂Mo₁₅V₃能够明显地抑制酪氨酸酶的活性,其半抑制浓度(IC₅₀)值分别为0.409、0.386和0.386 mmol/L,且均表现为可逆的竞争型抑制,效应物P₂Mo₁₇V、P₂Mo₁₆V₂和P₂Mo₁₅V₃对游离酶的抑制常数K_I分别为0.234、0.391和0.249 mmol/L。 而效应物P₂Mo₁₄V₄在0~1.0 mmol/L浓度范围内,对酪氨酸酶二酚酶无明显抑制作用,效应物P₂Mo₁₃V₅对酪氨酸酶二酚酶表现为激活作用。     

侧基上带有C60基团的聚苯乙烯的表征

用UV、FTIk、DSC、TG和DTA及GPC等方法证明了通过三步反应(氯甲基化,叠氮化,环加成反应)确实将C₆₀引入到聚苯乙烯的侧基上,C₆₀基本上以单取代的方式存在,并通过TG和DTA方法估算了C₆₀在聚苯乙烯C₆₀衍生物中的含量。     

Oriental lacquer,poison ivy,and drying oils

From the oriental lacquer tree Toxicodendron vernicifluum, a sap (emulsion) is obtained the oil‐soluble components (urushiol) of which consist of a mixture of 3‐n‐pentadecylcatechols and very small amounts of 3‐n‐heptadecylcatechols. Urushiol is the basis of oriental lacquer. The sap is conditioned by removal of most of the water by specific techniques, and the clear liquid is called oriental lacquer. It is used in the Orient for coatings to produce exquisite art objects. Poison ivy also has as its active ingredients 3‐n‐pentadecylcatechols, but they have a high diene content, which does not cure effectively. In humans 3‐n‐alkylcatechols cause severe contact dermatitis. The components of drying oils are glycerin esters of fatty acids derived from the families of palmitic (hexadecanoic) and stearic (octadecanoic) acids. In the case of the urushiols, as well as of the glycerides of drying oils, high unsaturation (60%) in the form of trienes in the long aliphatic chains is essential for curing. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4327–4335, 2000     

Development and Characterization of Laccol Lacquer Blended with Urushiol Lacquer

A lacquer blending urushiol and laccol was investigated. The blended lacquer with 30wt.% urushiol and 100wt.% laccol has a good drying property and film hardness. 2-D-NMR and FD-MS measurements of the lacquer dimer showed that a transfer of radicals between urushiol and laccol occurred during the enzymatic polymerization, and 4-4′ biphenyl, 4-6′ (4′-6), and 6-6 (6-6′) dibenzofuran structures were obtained.     

Characterization of lipid components of Melanorrhoea usitata lacquer sap

The lipid component of Melanorrhoea usitata lacquer sap isolated by acetone was analyzed and compared to synthesized ω-phenylalkylcatechols and ω-phenylalkylphenols. In addition, laccol and urushiol analogues synthesized in our laboratory were used as standard materials to analyze the lipid component of the Myanmar lacquer sap. The GC and GC/MS measurements confirmed the results of Kumanotani and Du that neither ω-phenylalkylcatechol nor ω-phenylalkylphenol exist in the lacquer saps from Rhus vernicifera and R. succedanea.     

Studies of Japanese lacquer: Urushiol dimerization by the coupling reaction between urushiol quinone and a triolefinic component of urushiol

Previously, the formation of urushiol quinone from urushiol was demonstrated in the laccase-catalyzed oxidation process of the sap of the Japanese lacquer tree (Rhus vernicifera D.C.) or of lacquer formed from it. This paper presents the results of the investigation on the participation of urushiol quinone in the oxidative polymerization and crosslinking of the sap or the lacquer. The polymeric urushiol was obtained by the fractionation of the mildly oxidized sap (Japanese lacquer), and a specific dimeric urushiol was isolated from it by thin-layer chromatography (TLC). Structural analysis of the dimer illustrated that it has a conjugated triene structure and may be formed by a coupling reaction between urushiol quinone and a triolefinic component of urushiol. Further support for this was given by the spectroscopic study of the reaction between 4-tert-butyl-o-quinone and the triolefinic component of dimethylurushiol, and by the isolation and identification of the coupling product between them.     

Synthesis of Rhus succedanea lacquer film and analysis by pyrolysis-gas chromatography/mass spectrometry

Laccol, a major component of lacquer sap from Rhus succedanea, was synthesized by a Witting reaction, and then mixed with acetone powder separated from raw lacquer sap to synthesize lacquer films. The resulting lacquer films were analyzed by pyrolysis gas chromatography/mass spectrometry (Py-GC/MS), and the results were compared with that of natural lacquer film to evaluate the polymerization mechanism and film structure. The results showed that saturated and monoenyl laccol components were present only in the natural lacquer film, but not in the synthesized lacquer films. Meanwhile, alkylphenols, alkebulphenols, alkanes, and alkenes having longer carbon chains than the side chains were detected in the synthesized laccol, suggesting that the polymerization of synthetic laccol proceeds through the laccase-catalyzed nucleus-side chain CO coupling and autoxidative side chain to side chain CC coupling like natural lacquer film. The synthesized laccol films showed shallow color and hardness, which would make them useful as good preservative surface-coating materials.     

Analysis and Characterization of Korean Lacquer

Three kinds of Korean lacquer saps were analyzed including chemical composition, enzymatic activity, molecular weight distribution, unsaturated degree of side chain, and drying property. The results were compared with Chinese and Japanese lacquer saps all collected in the same month (August 2012 and 2013) to investigate similarities and differences. Compared with Chinese and Japanese saps, the Korean lacquer sap contains the most lipids (84.9%) and urushiol triene (56.1%) components and the second highest enzyme activity after Chinese lacquer sap. In the drying and film hardness test, Korean and Chinese film reached a stronger hardness sooner than Japanese lacquer film; in 21 days the former reached 2H and the latter only H. The results of IR, NMR, and GC-MS analysis showed slight differences due to different growing conditions.     

Molecular identification of Asian lacquers from different trees using Py‐GC/MS and ToF‐SIMS

Traditional Asian lacquers are natural products with highly valued properties, including beauty, gloss, and durability. Pyrolysis‐gas chromatography/mass spectrometry is the technique of choice to study insoluble polymeric lacquer films. In the present study, pyrolysis‐gas chromatography/mass spectrometry results showed that the pyrolysis products of lacquer films were different for all of the studied trees, with urushiol derivatives detected in Toxicodendron vernicifluum from China, Japan, and Korea; laccol in Toxicodendron succedaneum from Vietnam; and thitsiol in Gluta usitata from Myanmar. Time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) was also used to characterize the Asian lacquers, avoiding the time‐consuming and destructive processes of other techniques. The ToF‐SIMS spectra provided structural characterization of a series of urushiol, laccol, and thitsiol derivatives for T vernicifluum from China, Japan, and Korea; T succedaneum from Vietnam; and G usitata from Myanmar, respectively. To differentiate the ToF‐SIMS results for the different Asian lacquer films, principal component analysis was used because it can extract differences in the spectra and indicate what peaks are responsible for these differences. The results indicate that lacquer films from different lacquer trees can be very different. Therefore, ToF‐SIMS with principal component analysis is suitable for the characterization and differentiation of Asian lacquer films in cultural heritage applications.     

Characterization of Chinese Lacquer in Historical Artwork by On-Line Methylation Pyrolysis-Gas Chromatography/Mass Spectrometry

An effective method for characterizing Chinese lacquer as binding medium in historical artwork has been developed by on-line methylation pyrolysis-gas chromatography–mass spectrometry (pyrolysis GC–MS). The characteristic pyrolytic components of Chinese lacquer were identified in artificially aged pure and pigmented lacquer. Methylation of urushiol (mainly composed of catechol derivatives) was performed by adding tetramethyl ammonium hydroxide to convert phenolic hydroxyl groups into methylated derivatives to improve the resolution of catechol derivatives and urushiol monomers. The mechanism of formation of small molecular components was proposed, and the influence of different mineral pigments (azurite, malachite, ochre, and cinnabar) on the determination of characteristic components was discussed. Aliphatic hydrocarbon components, benzene derivatives, catechol derivatives, and urushiol monomers were proposed as characteristic pyrolytic components. In addition to 3-pentadecene-catechol, 3-pentadecane-catechol, and 3-heptadecene-catechol, 3-pentadecene-phenol was also identified as an urushiol monomer in Chinese lacquer. Four pigments slightly reduced the detection of aliphatic hydrocarbon components, but were unconspicuous for the detection of benzene derivatives. Azurite, malachite, and cinnabar decreased the measurement of urushiol monomers, but ochre significantly increased their relative abundance. The established on-line methylation pyrolysis GC–MS procedure and summarized data were successfully applied to the identification of samples collected from Terra-Cotta Warriors and Horses of Qin Dynasty (221–207 BC), Han Yang Mausoleum of Han Dynasty (206 BC–24 AD), and Dazu Grotto of Tang Dynasty (618–907 AD).     

Dimer Structures and Laccase-Catalyzed Polymerization Mechanism of Laccol in Fresh Rhus Succedanea Lacquer Sap

Laccase-catalyzed polymerization of laccol was promoted by a kneading process, and the molecular weight distribution and drying properties were examined. The laccol dimers were separated and purified by HPLC, and the chemical structures were characterized by IR, GC-MS, and NMR spectroscopy involving two-dimensional NMR measurements. Two sorts of C-C coupling, nuclear-nuclear (C-C) and nuclear-side chain (C-C), were found in the laccol dimer, which differ from the nuclear-side chain (C-O-C) couplings of urushiol and the only nuclear-nuclear (C-C) couplings of thitsiol. Based on these results, the properties of laccol lacquer film and the laccase-catalyzed polymerization mechanism of laccol are discussed.     

Zn2+@Polyvinylpyrrolidone and Urushiol Preparation of Nanofibrous Membranes and Their Synergistic Effect

In this study, lacquer is gathered from a lacquer tree and rotary evaporation is used to remove impurities to obtain urushiol. Next, 10 mL of anhydrous ethanol serves as the solvent for blending polyvinylpyrrolidone (PVP) at a specified content (0.7 g and 0.2–0.7 g urushiol) to form an electrospinning solution. Electrospinning is carried out with a voltage of 18 kV to prepare PVP/urushiol nanofibrous membranes. At a ratio of 7/4, the PVP/urushiol nanofibrous membranes are not eroded in 98% sulfuric acid and these membranes also demonstrate a 50–60% antibacterial effect against Staphylococcus aureus and Escherichia coli. Moreover, the antibacterial effect can be boosted to 98% with the incorporation of zinc ions. The results indicate that anhydrous ethanol can remove the sensitization of urushiol from PVP/urushiol membranes. Furthermore, animal test results indicate that when rats are in contact with PVP/urushiol anhydrous ethanol for 48 h, their skins are free from dark brown skin allergy. The presence of PVP eliminates the sensitization of urushiol, and the nanofibrous membranes demonstrate low toxicity. Hence, urushiol is the only natural material that enables PVP to withstand 98% sulfuric acid as well as acquire hydrolyzability, thereby qualify PVP as a medical material.