荧光光谱结合表面增强拉曼光谱法研究紫檀芪与人血清白蛋白相互作用

在模拟人体生理条件下,应用荧光光谱和表面增强拉曼光谱法研究了紫檀芪(PTE)与人血清白蛋白(HSA)之间相互作用机制.结果表明,HSA的荧光能被PTE静态猝灭,并伴随有非辐射能量转移作用,两者形成了1:1复合物,结合距离r=1.495 nm,结合常数KA=1.12×104(298 K)、4.07×104(304 K)和2.45×105 L/mol(310 K).表面增强拉曼光谱研究揭示,PTE分子通过甲氧基与HSA进行结合;热力学数据表明,二者间的作用主要为疏水作用;标记竞争实验指出PTE优先结合HSA的位点Ⅲ.三维荧光光谱、同步荧光光谱和表面增强拉曼光谱结果显示,与PTE作用后,HSA构象发生变化,导致色氨酸残基周围环境疏水性降低,但对PTE分子构象影响不大.     

紫檀茋壳聚糖微球的制备及其体外释放性能

以大豆油为分散介质,SPAN-80为乳化剂,戊二醛为交联剂,采用乳化交联固化法制备了紫檀芪壳聚糖微球(PCM).其形貌与性能经Fr-IR,SEM和DSC表征.以粒径分布和包封率为评价指标对制备工艺进行优化.在优化条件下制备的PCM呈圆形,粒径9μm一12μm,包封率(21.0±1.5)%,具有良好的分散性、稳定性以及明...     

高效液相色谱法测定葡萄叶中5种芪化物

建立了同时检测葡萄叶片中白藜芦醇(resveratrol,Res)、云杉苷(piceide,PD)、ε-葡萄素(ε-viniferin)、δ-葡萄素(δ-viniferin)、紫檀芪(pterostilbene,PS)5种芪化物的高效液相色谱分析方法.采用Atlantis C18色谱柱 (250 mm×4.6 mm, 5 μm), 流动相为乙腈、水梯度洗脱,二极管阵列检测器,检测波长为306 nm;流速1 mL/min; 柱温30 ℃,外标法定量.结果显示: 5种芪化物的线性关系良好,相关系数在0.9990～0.9996之间;精密度、稳定性的RSD都低于5%;平均回收率为90.3%～114.0%,检出限为0.01～0.05 mg/L.本方法前处理简单、快速.应用本方法测定了葡萄叶片紫外诱导后5种芪化物的含量变化,结果令人满意.     

新型黄酮半乳糖缀合物的合成与生物活性研究

以香叶木素或野漆树苷为原料,经过O-甲基化、酸性水解、O-苄基化和过氧丙酮(DMDO)氧化等反应步骤,合成了5,7,3’,4’-四甲氧基黄酮醇(1),5,7,3’-三苄氧基-4’-甲氧基黄酮醇(2),5,7,4’-三甲氧基黄酮醇(3),金合欢素(4)和5,7-二羟基-4’-苄氧基黄酮(5),运用"点击化学"方法,将所合成黄酮类的炔基化合物6～10与β-叠氮化乙酰基半乳糖通过铜催化的1,3-偶极环加成反应链接起来,合成了一系列未见文献报道的新型黄酮半乳糖缀合物11～20.MTT蛋白染色法体外抗肿瘤细胞生物活性测试发现,化合物11,13和20对白血病细胞(HL-60)、肝癌细胞(SMMC-7721)、乳腺癌细胞(MCF-7)、结肠癌细胞(SW480)和肺癌细胞(A-549)具有一定的抑制活性.     

天然黄酮香叶木素类及其衍生物的合成与生物活性研究

以橙皮苷为原料,经脱氢、选择性甲基化、糖苷水解、相转移催化下的糖苷化反应、异戊烯基化和法呢烯基化等反应步骤,分别合成了3’-O-甲基香叶木素(1),香叶木素-7-O-β-D-葡萄糖苷(2),香叶木素-7-O-β-D-半乳糖苷(3),3’-O-甲基香叶木素-7-O-β-D-葡萄糖苷(4)4种天然产物及3’-O-甲基香叶木素-7-O-β-D-半乳糖苷(5),香叶木素-7-O-β-D-乙酰葡萄糖苷(6)、香叶木素-7-O-β-D-乙酰半乳糖苷(7),3’-O-甲基香叶木素-7-O-β-D-乙酰葡萄糖苷(8),3’-O-甲基香叶木素-7-O-β-D-乙酰半乳糖苷(9),7-O-异戊基香叶木素(10),7-O-异戊烯基-3’-O-甲基香叶木素(11)和7-O-法呢烯基-3’-O-甲基香叶木素(12)8种新的香叶木素衍生物.所合成化合物的结构已由核磁共振谱、红外光谱和质谱所证实,并用比色法MTT[3-(4,5-二甲基噻唑-2)-2,5-二苯基四氮唑溴盐]蛋白染色法对所合成的目标化合物进行了体外抗肿瘤细胞生物活性测试,发现化合物6,10和11对肝癌细胞(SMMC-7721)、乳腺癌细胞(MCF-7)和结肠癌细胞(SW480)有一定的抑制活性.     

柚皮苷半合成生物活性黄酮醇和橙酮类化合物研究

以柚皮苷为原料,经过糖苷水解、脱氢、苄基保护、O-甲基化、过氧丙酮(DMDO)氧化或阿尔格-弗林-大山田(Algar-Flynn-Oyamada)反应和脱苄基保护等反应步骤,半合成了山萘酚(1,Kaemferol),5,7,4’-三甲氧基黄酮醇(2)、3,5-二羟基-7,4’-二甲氧基黄酮醇(3),鼠李柠檬素(4,Rhamnocitrin)等4种天然黄酮醇类和4,6,4’-三羟基二氢橙酮(5)、4-羟基-6,4’-二甲氧基二氢橙酮(6)两种新的橙酮类化合物.重点探讨了过氧丙酮(DMDO)直接氧化黄酮制备黄酮醇和Algar-Flynn-Oyamada反应制备橙酮的合成方法,改进优化了反应条件.所有合成化合物的结构已通过1H NMR,MS和IR等波谱方法进行了确认.该合成途径原料易得,工艺简便,收率较高,具有较高的应用价值.     

(E)-脱氢二聚白藜芦醇四甲醚的全合成

以3, 5-二甲氧基苯甲酸(1)和对羟基苯甲醛(6)为起始原料, 经过以仿生氧化偶联为关键步骤的八步反应,对化合物10进行了全合成。通过1H NMR, 13C NMR, IR, HRMS等方法确定化合物10的结构为7, 8 - trans-7', 8'-trans-二聚芪类化合物,即(E)-脱氢二聚白藜芦醇四甲醚,结果表明利用本文方法成功合成了目标化合物。     

新型有机类杂芪染料的合成及其光物理性质研究

利用改进的碱缩合或酸催化反应,合成了8种类杂芪染料:反式-(2-N-甲基吡咯基)-(4-N-甲基吡啶基)杂芪碘(反式-MPPSI)、反式-(2-吡咯基)-(4-N-甲基吡啶基)杂芪碘(反式-PPSI)、反式-(2-呋喃基)-(4-N-甲基吡啶基)杂芪碘(反式-FPSI)、反式-(2-噻吩基)-(4-N-甲基吡啶基)杂芪碘(反式-TPSI)、反式-(4-N-甲基吡啶基)杂芪碘(反式-PSI)、反式-(4-甲基)-4(4-N-甲基吡啶基)杂芪碘(反式-MPSI)、反式-(4-胺基)-(4-N-甲基吡啶基)杂芪碘(反式-APSI)和反式-(4-N,N-二甲胺基)-(4-N-甲基吡啶基)杂芪碘(反式-DAPSI)其中PPSI、FPSI和TPSI为首次报道的新型染料.研究了这8种染料的基本光物理性质.应用线性Hammett方程,得到了类杂芪染料的电荷转移性质、荧光最大发射波数及Stock's位移和Hammett常数σ或五员杂环的富电子性ρ(C)_D间的线性相关性,由于类杂芪染料分子的最低跃迁能(υ_a)可与σ或ρ(C)_D线性相关,所以类杂芪染料的电转移态性质、荧光最大发射波数及Stock's位移也可与υ_a线性相关,从而得到了拓展的线性Hammett方程.     

两种天然异戊烯基黄烷酮的全合成

以3-甲氧基甲氧基苯甲醛和2,4,6-三甲氧基-3-异戊烯基苯乙酮为原料,经烷基化和缩合反应合成了新化合物——2’-羟基-4-甲氧基-3,4’,6’-三甲氧甲氧基-3’-异戊烯基査尓酮(6);6经环合反应合成了新化合物——(±)-5,7,3’-三甲氧甲氧基-4’-甲氧基-8-异戊烯基黄烷酮(7);7经脱保护和环合反应实现了天然产物(±)-5,7,3’-三羟基-4’-甲氧基-8-异戊烯基-黄烷酮(1,总收率11.6%)和(±)-5,3’-二羟基-7,8-(2,2-二甲基吡喃)-4’-甲氧基黄烷酮(2,总收率10.5%)的全合成,其中1为新化合物,其结构经1H NMR,IR和MS表征。     

哌嗪取代查尔酮衍生物的合成及其细胞毒活性

以4-甲氧基苯甲醛与2-溴-4’-氟苯乙酮为原料,经羟醛缩合脱水、取代反应生成4-甲氧基-4’-(1-哌嗪基)查尔酮(2),再通过酰化反应合成了10个新型含哌嗪的查尔酮衍生物,其结构经~1H NMR、~(13)C NMR及HRMS确证。采用MTT法初步测试了目标化合物的体外细胞毒活性,结果表明,化合物3e和4d对肿瘤细胞株Hela和A549均表现出较好的细胞毒活性,可做进一步研究。     

Synthesis of Pterostilbene by Julia Olefination

A simple, E-stereoselective route for the synthesis of the biologically active compounds trans-pterostilbene and tetramethoxy stilbene from the readily available starting materials 3,5-dimethoxy benzyl alcohol and 4-hydroxy benzaldehyde was developed using Julia olefination as a key reaction.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resources: Full experimental and spectral details.]     

Preparation and Characterization of Vanillin Cross-Linked Chitosan Microspheres of Pterostilbene

A vanillin cross-linked chitosan microsphere delivery system was established for stabilization and controlled release of pterostilbene. The prepared microspheres were characterized by SEM images, FT-IR spectra, thermogravimetry, and X-ray diffraction. FT-IR spectra results indicated that chitosan was cross-linked by vanillin successfully. Thermal analysis showed that pterostilbene had been totally incorporated into the microspheres and the encapsulation of pterostilbene decreases the rate of degradation and increases the stability. XRD analysis was conducted to confirm the results of DSC analysis. The release rate of pterostilbene from microspheres in pH 3.6 buffer solution could be up to 58.1 % within 48 h.     

Activity of Pterostilbene Metabolites against Liver Steatosis in Cultured Hepatocytes

Pterostilbene is a dimethyl ether derivative of resveratrol, less metabolized than its analogue, due to the substitution of two hydroxyl groups with methoxyl groups. Nevertheless, the amounts of pterostilbene phase II metabolites found in plasma and tissues are higher than those of the parent compound. The first aim of this study was to assess whether pterostilbene-4′-O-glucuronide (PT-G) and pterostilbene-4′-O-sulfate (PT-S) were able to prevent triglyceride accumulation in AML12 (alpha mouse liver 12) hepatocytes. This being the case, we aimed to analyze the mechanisms involved in their effects. For this purpose, an in vitro model mimicking the hepatocyte situation in fatty liver was developed by incubating mouse AML12 hepatocytes with palmitic acid (PA). For cell treatments, hepatocytes were incubated with 1, 10 or 25 µM of pterostilbene, pterostilbene-4′-O-glucuronide or pterostilbene-4′-O-sulfate for 18 h. Triglycerides and cell viability were assessed by a commercial kit and crystal violet assay, respectively. Protein expression of enzymes and transporters involved in triglyceride metabolism was analyzed by immunoblot. The results showed for the first time the anti-steatotic effect of pterostilbene metabolites and thus, that they contribute to the preventive effect induced by pterostilbene on steatosis in in vivo models. This anti-steatotic effect is mainly due to the inhibition of de novo lipogenesis.     

Enhancement of Anticancer Potential of Pterostilbene Derivative by Chalcone Hybridization

Pterostilbene, a natural metabolite of resveratrol, has been indicated as a potent anticancer molecule. Recently, several pterostilbene derivatives have been reported to exhibit better anticancer activities than that of the parent pterostilbene molecule. In the present study, a series of pterostilbene derivatives were designed and synthesized by the hybridization of pterostilbene, chalcone, and cinnamic acid. The cytotoxic effect of these hybrid molecules was determined using two oral cancer cell lines, HSC-3 and OECM-1. (E)-3-(2-((E)-4-Hydroxystyryl)-4,6-dimethoxyphenyl)-1-(2-methoxyphenyl)prop-2-en-1-one (4d), with IC₅₀ of 16.38 and 18.06 μM against OECM-1 and HSC-3, respectively, was selected for further anticancer mechanism studies. Results indicated that compound 4d effectively inhibited cell proliferation and induced G2/M cell cycle arrest via modulating p21, cyclin B1, and cyclin A2. Compound 4d ultimately induced cell apoptosis by reducing the expression of Bcl-2 and surviving. In addition, cleavage of PARP and caspase-3 were enhanced following the treatment of compound 4d with increased dose. To conclude, a number of pterostilbene derivatives were discovered to possess potent anticancer potentials. Among them, compound 4d was the most active, more active than the parent pterostilbene.     

Pterostilbene: A Highly Reliable Quality-Control Marker for the Ayurvedic Antidiabetic Plant `Bijasar'

Summary In the Indian Ayurvedic system of medicine the heart wood of Bijasar (Lat: Pterocarpus marsupium; Fam: Leguminaceae) has been extensively used to treat diabetes mellitus. Detailed chemical and HPTLC analysis has been performed to identify a reliable marker for quality control of Pterocarpus marsupium and to check commercial samples for authenticity and purity. The two anti-diabetic principles viz. pterostilbene (1) and marsupsin (2) were isolated by extensive chromatographic screening of its ethyl acetate extract. HPTLC studies of these two compounds revealed that levels of pterostilbene are several times more than that of marsupsin both in plant samples and in commercial formulations. The HPTLC method gave reproducible results and response was linearly dependent on amount analysed in the range 200–500 ng. Pterostilbene can therefore be regarded as a reliable marker for evaluation of the quality of Pterocarpus marsupium.     

Furyl- and thienyl-silatranes and germatranes

We review our research on the synthesis and study of the physical and biological properties of furyl- and thienylgermatranes and -silatranes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 725–732, June, 1992.     

Review and patents and literature

The use of the insect cell/baculovirus expression system for producing recombinant proteins of bacterial, plant, insect, and mammalian origin has become widespread. The popularity of this eukaryotic expression system is due to many factors, including (1) potentially high protein expression levels, (2) ease and speed of genetic engineering, (3) ability to accommodate large DNA inserts, (4) protein processing similar to higher eukaryotic cells (e.g., mammalian cells), and (5) ease of insect cell growth (e.g., suspension growth). The following review of the literature discusses two engineering aspects of recombinant protein synthesis by insect cell cultures: bioreactor scale-up and insect cell line selection. Following this review patent abstracts and additional literature pertaining to expression of recombinant proteins in insect cell culture are listed.