生物素化白藜芦醇的分离纯化与药效学评价

以DCC为催化剂,采用低温化学催化法合成生物素化白藜芦醇.产物采用Resourse RPC反相色谱柱分离、纯化,并且运用液质联用进行分析验证.MTT法测定产物体外对Hep G2、MCF-7肿瘤细胞的抑制作用.实验结果显示:通过HPLC-MS、紫外扫描分析鉴定证实,分离得到的产物确实是生物素化白藜芦醇,其保留了原有的体外抗肿瘤活性.此种化学合成方法反应条件温和,容易控制,操作方便.合成得到的白藜芦醇的生物素化衍生物,为下一步探讨白藜芦醇的结合蛋白提供简单有效的分子工具.     

丹参酮ⅡA磺酸钠合成工艺研究

为改善丹参酮的水溶性,在其分子中引入水溶性官能团磺酸基.以不同的磺化剂与之发生磺化反应,结果表明,冰醋酸一浓硫酸的混合液是合成丹参酮水溶性衍生物的合适磺化剂.通过薄层色谱法、紫外吸收和红外吸收光谱法对其结构进行鉴定,证实了产物是丹参酮ⅡA磺酸钠.对以冰醋酸-浓硫酸为磺化剂合成丹参酮ⅡA磺酸钠进行了正交试验研究,得出其最佳工艺条件为:冰醋酸-浓硫酸(1:1,v/v),反应温度15℃,反应时间1 h,产品得率38.7%.     

新型氮杂多肽酰肼类衍生物的设计、合成和抗肿瘤活性研究

目的:新型氮杂多肽酰肼类衍生物的设计和合成及其抗肿瘤活性研究。方法:以脯氨酸甲酯盐酸盐为原料,通过与苄氧羰基丙氨酸反应,在肼中肼解,得到所需中间体,进而与富马酸单酯反应得到目标化合物;和溴乙酸叔丁酯反应,三氟乙酸中脱去叔丁氧基,再与取代胺或氨水反应得到目标化合物。用MTT法测试合成的氮杂多肽酰肼类衍生物对肿瘤细胞的抑制活性。结果:合成了10个氮杂多肽酰肼类衍生物,其中有6个化合物对肿瘤细胞表现出抑制活性。结论:初步建立了氮杂多肽酰肼类衍生物的合成方法及其对肿瘤细胞抑制活性的构效关系。     

新型2-喹诺酮类Polo样激酶1抑制剂的设计合成及分子对接研究

目的:设计合成新型2-喹诺酮类Polo样激酶1(Plk1)抑制剂。方法:以Plk1抑制剂ON 01910为先导化合物,利用生物电子等排原理设计一系列2-喹诺酮类衍生物,用Autodock软件将该类化合物与Plk1进行分子对接和虚拟筛选,计算结合自由能;以取代的氯(溴)苄为起始原料,先后经巯基乙酸取代、双氧水氧化、与(对甲氧基)苯胺酰化,再经环合、水解制得目标化合物。结果:设计的化合物大多数与Plk1的结合自由能均比ON 01910的低,结合强度高、稳定性好;合成了16个2-喹诺酮类衍生物,产物结构经1H-NMR确证。结论:所得化合物中有15个为新化合物,化合物的结构设计科学合理,虚拟筛选结果良好,为后续实体筛选和化合物结构优化提供了理论依据和参考。     

萘查耳酮类化合物的设计合成及对CYP1B1酶的抑制活性评价

目的:设计并合成几类新型的萘查耳酮衍生物,初步测定其对CYP1B1酶的抑制活性,筛选具有良好抗癌作用的CYP1B1抑制剂。方法:以1,5-二羟基萘为原料,首先合成两个重要的中间体2-乙酰基-1,4,5,8-四甲氧基萘、1,5,6-三甲氧基-2-萘乙酮,然后利用羟醛缩合反应合成所需要的化合物。结果:合成了19个目标化合物,其结构均经过核磁共振氢谱确证,所有化合物均为全新化合物。对所合成的新化合物均进行了EROD酶实验测定。结论:所合成的化合物均具有较强的CYP1B1酶一抑制活性,其中4-1、4-2、5'-1对CYP1B1的抑制活性强于CYP1B1强抑制剂α-萘黄酮(IC50=11 nmol/L),他们的IC50分别为6.5、0.47、8nmol/L。     

碱催化合成4-甲基-2'-羟基-4'-甲氧基查尔酮及其晶体结构

探讨超声波辅助下用碱催化合成查尔酮的方法。常温超声波辅助下用碱催化使丹皮酚和4-甲基苯甲醛发生克莱森-斯密特反应,生成一种含有1,3-二苯基丙烯酮结构的丹皮酚衍生物:4-甲基-2'-羟基-4'-甲氧基查尔酮,产率高达71.57%,经过现代光谱学技术紫外、红外、质谱并结合核磁的氢谱、碳谱以及135°DEPT谱表征其结构。用X射线衍射技术分析该丹皮酚衍生物的单晶结构并确定其分子的构型和构象,4-甲基-2'-羟基-4'-甲氧基查尔酮属于单斜晶系中的P2(1)/n空点群,晶胞参数:a=1.1288(10)nm、b=0.6916(6)nm、c=2.0509(4)nm、α=90.0(8)°、β=109.8(8)°、γ=90(8)°,晶胞体积V为1.4056(5)nm3,密度Dc为1.272 mg/cm3。在超声波辅助下用碱催化可使丹皮酚和4-甲基苯甲醛通过克莱森-斯密特反应来合成含有1,3-二苯基丙烯酮结构的丹皮酚衍生物。     

丹参酮IIA衍生物的合成

目的:丹参酮IIA是中药丹参的脂溶性成分,具有抗肿瘤、抗氧化、抗心脑血管疾病等多种生理活性。本文拟对其进行结构改造以获得活性更好的丹参酮IIA衍生物。方法:首先,以丹参酮IIA为原料,通过Vilsmeier反应在其16-位引入醛基,再与醋酸胺进行还原胺化反应,以较高收率得到16-位胺甲基取代的丹参酮IIA衍生物。接着,对其氨基进行修饰,得到10个不同N-取代的丹参酮IIA衍生物。同时考察反应温度、反应溶剂和反应时间等条件对还原胺化反应的影响,确定最佳反应条件。结果:通过1H-NMR、13C-NMR以及LC-MS对所有产物结构进行了确认。还原胺化反应的最佳反应条件为:以1,2-二氯乙烷为溶剂,温度保持40℃,反应时间为2h。结论:反应步骤简单、条件温和、产率较高,是合成16-位取代的丹参酮IIA衍生物的理想方法。     

天然产物5,6,7,3′,4′-五甲氧基异黄酮的合成(英文)

以3,4-二甲氧基苯乙酸和3,4,5-三甲氧基苯酚为原料,通过一条包括酯化反应、Fries重排、以及Vilsmeier-Haack反应等5步反应的路线合成了天然产物5,6,7,3′,4′-五甲氧基异黄酮。根据3,4,5-三甲氧基苯酚计算目标产物的总收率为76%,利用NMR及元素分析确证了化合物的结构。     

昆虫拒食剂蓼二醛的合成及其对害虫的拒食活性

以 β-环柠檬醛为原料 ,经 6步合成了蓼二醛 ( ( -) -polygodial)的消旋体 ,总收率为 1 9 8% ;并合成了其甲胺衍生物。经生物活性测定 ,辣蓼的粗提物和合成的蓼二醛及其甲胺的衍生物对蚜虫和菜青虫有很好的拒食活性     

柚皮素-7-O-乙酸酯和柚皮素-7-O-丙酸酯的制备及抗血小板聚集活性

为改善柚皮素的水溶性而不降低其抗血小板聚集活性,本文以柚皮苷为原料,经"4'位羟基苄基化-酸水解苷键-酰化-加氢脱苄基"四步反应,合成出柚皮素-7-O-乙酸酯和柚皮素-7-O-丙酸酯。两种衍生物在水中的溶解度分别为637.34±53.23μg/m L和59.74±4.81μg/m L,均高于柚皮素的溶解度。两种衍生物均对二磷酸腺苷诱导的兔体外和大鼠体内血小板聚集有显著的抑制活性,且抑聚率均高于柚皮素。实验结果表明,通过选择酰化柚皮素的7位羟基,引入含1~2个碳的短脂肪烃基链,能显著改善水溶性,提高抗血小板聚集活性。     

Structure-activity relationship studies of resveratrol and its analogues by the reaction kinetics of low density lipoprotein peroxidation

Resveratrol (3,5,4'-trans-trihydroxystibene) is a natural phytoalexin present in grapes and red wine, which possesses a variety of biological activities including antioxidative activity. To find more active antioxidants, with resveratrol as the lead compound, we synthesized resveratrol analogues, i.e., 3,4,3',4'-tetrahydroxy-trans-stilbene (3,4,3',4'-THS), 3,4,4'-trihydroxy-trans-stilbene (3,4,4'-THS), 2,4,4'-trihydroxy-trans-stilbene (2,4,4'-THS), 3,3'-dimethoxy-4,4'-dihydroxy-trans-stilbene (3,3'-DM-4,4'-DHS), 3,4-dihydroxy-trans-stilbene (3,4-DHS), 4,4'-dihydroxy-trans-stilbene (4,4'-DHS), 3,5-dihydroxy-trans-stilbene (3,5-DHS) and 2,4-dihydroxy-trans-stilbene (2,4-DHS). Antioxidative effects of resveratrol and its analogues against free-radical-induced peroxidation of human low density lipoprotein (LDL) were studied. The peroxidation was initiated either by a water-soluble initiator 2,2'-azobis(2-amidinopropane hydrochloride) (AAPH), or by cupric ion (Cu(2+)). The reaction kinetics were monitored either by the uptake of oxygen and the depletion of alpha-tocopherol (TOH) presented in the native LDL, or by the formation of thiobarbituric acid reactive substances (TBARS). Kinetic analysis of the antioxidation process demonstrates that these trans-stilbene derivatives are effective antioxidants against both AAPH- and Cu(2+)-induced LDL peroxidation with the activity sequence of 3,4,3',4'-THS approximately 3,3'-DM-4,4'-DHS>3,4-DHS approximately 3,4,4'-THS>2,4,4'-THS>resveratrol approximately 3,5-DHS>4,4'-DHS approximately 2,4-HS, and 3,4,3',4'-THS approximately 3,4-DHS approximately 3,4,4'-THS>3,3'-DM-4,4'-DHS>4,4'-DHS>resveratrol approximately 2,4-HS>2,4,4'-THS approximately 3,5-DHS, respectively. Molecules bearing ortho-dihydroxyl or 4-hydroxy-3-methoxyl groups possess significantly higher antioxidant activity than those bearing no such functionalities.     

Enzymatic synthesis of a 6-sialyl lactose analogue using a pH-responsive water-soluble polymer support

The Letter describes a strategy for the enzymatic synthesis of glycans based on a pH-responsive water-soluble polymer. In neutral condition, the polymer is water-soluble and convenient for in-solution enzymatic synthesis, whereas in acidic condition (pH lower than 4.0), the polymer disconnects with the product and becomes insoluble, which can be easily removed. A 6-Sialyl lactose analogue was synthesized as a model reaction using this approach.     

Resveratrol Binding to Fibrinogen and its Biological Implication

In light of important implication of fibrinogen and resveratrol in the platelet aggregation and thrombus formation, the interaction between them was studied, and its biological implication was further explained. Fibrinogen could interact with resveratrol to form 1:1 complex with the binding constant of 1.11 × 10⁴ M⁻¹. The binding was spontaneous and fibrinogen/resveratrol complex formation was an exothermal reaction. Electronic interaction and hydrogen bonding played key roles and non-radiation energy transferred from fibrinogen to resveratrol in the binding process. Kinetic study indicated that resveratrol linearly combined to fibrinogen along with the prolonged time. The addition of resveratrol changed fibrinogen conformation including its second structure resulting in increase of polarity around tyrophore residue and decrease of α-helical structure in the protein. Additionally, fibrinogen obviously increased resveratrol stability. It would give a deeper insight into resveratrol as a kind of functional factor.     

3,4,4'-Trihydroxy-trans-stilbene, an analogue of resveratrol, is a potent antioxidant and cytotoxic agent

Resveratrol (3,5,4'-trihydroxy-trans-stilbene) is a naturally occurring polyphenol widely distributed in food and dietary plants. This phytochemical has been intensively studied as an efficient antioxidant and anticancer agent, and a variety of substituted stilbenes have been developed in order to improve the potency of resveratrol. In this work, we described the synthesis of 3,4,4 -trihydroxy-trans-stilbene (3,4,4'-THS), an analogue of resveratrol, and studied its antioxidant and cytotoxic activity in vitro. 3,4,4 -THS was much more efficient than resveratrol in protecting against free radical-induced lipid peroxidation, photo-sensitized DNA oxidative damage, and free radical-induced hemolysis of human red blood cells. More potent growth inhibition in cultured human leukemia cells (HL-60) was also observed for 3,4,4 -THS. The relationship between the antioxidant efficiency and cytotoxic activity was discussed, with the emphasis on inhibition of the free radical enzyme ribonucleotide reductase by antioxidants. The result that this subtle structure modification of resveratrol drastically improves its bioactivity provides important strategy to develop novel resveratrol-based molecules.     

Effect of Lipolysis on Drug Release from Self-microemulsifying Drug Delivery Systems (SMEDDS) with Different Core/Shell Drug Location

The objective of this study is to investigate the effect of lipolysis on the release of poorly water-soluble drug from SMEDDS in the perspective of drug core/shell location. For this purpose, four SMEDDS formulations with various core/shell properties were developed based on long-chain lipid or medium-chain lipid as well as different surfactant/oil ratios. Poorly water-soluble drugs, hymecromone and resveratrol, were significantly solubilized in all SMEDDS formulations and the diluted microemulsions. Fluorescence spectra analysis indicated that hymecromone was mainly located in the shell of microemulsions, while resveratrol was located in the core. The effect of lipolysis on the release rates of drugs with different core/shell locations were investigated by a modified in vitro drug release model. For the drug located in the shell, hymecromone, the release profiles were not affected during the lipolysis process and no significant differences were observed among four formulations. For the drug located in the core, resveratrol, the release rates were increased to various degrees depending on the extent of digestion. In conclusion, the drug core/shell location plays an important role for determining the effect of lipolysis on drug release from SMEDDS formulation.     

Pulse radiolysis study of the reactivity of Trolox C phenoxyl radical with superoxide anion

The reaction between the phenoxyl radical of Trolox C, a water-soluble vitamin E analogue, and superoxide anion radical was examined by using the pulse radiolysis technique. The results indicate that the Trolox C phenoxyl radical may undergo a rapid one-electron transfer from superoxide radical [k = (4.5 +/- 0.5) x 10(8) M-1.S-1] to its reduced form. This finding indicates that superoxide radical might play a role in the repair of vitamin e phenoxyl radical.     

Use of In Vitro and Predictive In Silico Models to Study the Inhibition of Cytochrome P4503A by Stilbenes

CYP3A4 is recognized as the main enzyme involved in the metabolism of drugs and xenobiotics in the human body and its inhibition may lead to undesirable consequences. Stilbenes, including resveratrol, belong to a group of dietary health-promoting compounds that also act as inhibitors of CYP3A4. The aim of this study was to examine the use of computer modeling of enzyme-ligand interactions to analyze and predict the inhibition of structurally related compounds. To this end, an aldehyde group was attached to resveratrol and the interactions of CYP3A4 with resveratrol, its aldehyde analogue (RA) and a known synthetic inhibitor were studied and compared in two biological models. Specifically, the metabolism of testosterone was examined in a human intestine cell line (Caco-2/TC7) and in rat liver microsomes (RLM). The results demonstrated a weak inhibitory effect of RA on CYP3A4, as compared to resveratrol itself, in both biological models. Human CYP3A4 was more susceptible to inhibition than the commonly used model isozyme from rat. Modeling of the binding site of CYP3A4 revealed a combination of three types of interactions: hydrophobic interactions, electrostatic interactions and hydrogen bonds. A docking simulation revealed that the RA lacked an important binding feature, as compared to resveratrol, and that that difference may be responsible for its lower level of affinity for CYP3A4. Software analysis of binding affinity may serve as a predictive tool for designing new therapeutic compounds in terms of inhibition of CYP3A4 and help to reveal the biochemical nature of the interactions of dietary compounds, herbal compounds and drugs whose metabolism is mediated by this enzyme.     

白藜芦醇对人子宫内膜癌细胞系AN3CA 增殖和凋亡效应 及其机制探讨

目的:探讨白藜芦醇(resveratrol,Res)对人子宫内膜癌细胞AN3CA的增殖抑制和凋亡诱导效应及可能存在的机制。方法:应用噻唑蓝(MTT)法检测Res对AN3CA的增殖影响;流式细胞术检测Res对细胞周期分布和凋亡影响;荧光实时定量PCR检测Res对细胞Bcl-2、Bax和MMP-9mRNA表达水平的影响;Western Blot方法检测Res对PCNA、Bcl-2、Bax及ERK1/2、p-ERK1/2蛋白表达水平的影响。结果:Res对子宫内膜癌细胞AN3CA具有显著的生长抑制作用(P<0.01),呈时间-剂量依赖性;不同浓度Res处理细胞G0/G1期比例显著增加伴随S期细胞数的减少;细胞凋亡率明显增高,200μmol/l Res处理48h凋亡率可达30.96%±2.041%(P<0.01)。与对照组相比,Res能抑制PCNA的蛋白表达量,增加Bax和降低Bcl-2转录和蛋白水平的表达量。Res在短时间内(0.5-1h)激活ERK1/2的磷酸化表达但随着作用时间延长(4-48h)其表现为抑制效应。结论:Res具有抑制AN3CA细胞增殖,诱导细胞G0/G1期阻滞和凋亡的效应。Res诱导凋亡可能是通过上调Bax,下调Bcl-2发挥作用,其抗癌作用机制可能与ERK1/2通路失调相关。     

A blend of two resveratrol derivatives abolishes hIAPP amyloid growth and membrane damage

Type II diabetes mellitus (T2DM) is characterized by the presence of amyloid deposits of the human islet amyloid polypeptide (hIAPP) in pancreatic β-cells. A wealth of data supports the hypothesis that hIAPP's toxicity is related to an abnormal interaction of amyloids with islet cell membranes. Thus, many studies aimed at finding effective therapies for T2DM focus on the design of molecules that are able to inhibit hIAPP's amyloid growth and the related membrane damage as well. Based on this view and inspired by its known anti-amyloid properties, we have functionalized resveratrol with a phosphoryl moiety (4′-O-PR) that improves its solubility and pharmacological properties. A second resveratrol derivative has also been obtained by conjugating resveratrol with a dimyristoylphosphatidyl moiety (4′-DMPR). The use of both compounds resulted in abolishing both amyloid growth and amyloid mediated POPC/POPS membrane damage in tube tests. We propose that a mixture of a water-soluble anti-aggregating compound and its lipid-anchored derivative may be employed as a general strategy to prevent and/or to halt amyloid–related membrane damage.     

Comparative studies of the antioxidant effects of a naturally occurring resveratrol analogue – <Emphasis Type="Italic">trans</Emphasis>-3,3′,5,5′-tetrahydroxy-4′-methoxystilbene and resveratrol – against oxidation and nitration of biomolecules in blood platelets

The action of two phenolic compounds isolated from the bark of Yucca schidigera: trans-3,3',5,5'-tetrahydroxy-4'-methoxystilbene and its analogue -- resveratrol (trans-3,4',5-trihydroxystilbene, present also in grapes and wine) on oxidative/nitrative stress induced by peroxynitrite (ONOO(-), which is strong physiological oxidant and inflammatory mediator) in human blood platelets was compared. The trans-3,3',5,5'-tetrahydroxy-4'-methoxystilbene, like resveratrol, significantly inhibited protein carbonylation and nitration (measured by enzyme-linked immunosorbent assay method) in the blood platelets treated with peroxynitrite (0.1 mM) and markedly reduced an oxidation of thiol groups of proteins (estimated with 5,5'-dithio-bis(2-nitro-benzoic acid)] or glutathione (measured by high performance liquid chromatography method) in these cells. The trans-3,3',5,5'-tetrahydroxy-4'-methoxystilbene, like resveratrol, also caused a distinct reduction of platelet lipid peroxidation induced by peroxynitrite. The obtained results indicate that in vitro trans-3,3',5,5'-tetrahydroxy-4'-methoxystilbene and resveratrol have very similar protective effects against peroxynitrite-induced oxidative/nitrative damage to the human platelet proteins and lipids. Moreover, trans-3,3',5,5'-tetrahydroxy-4'-methoxystilbene proved to be even more potent than resveratrol in antioxidative tests. We conclude that the novel tested phenolic compound -- trans-3,3',5,5'-tetrahydroxy-4'-methoxystilbene isolated from Y. schidigera bark possessing Generally Recognized As Safe label given by the Food and Drug Administration and allows their human dietary use -- seems to be a promising candidate for future evaluations of its antioxidative activity and may be a good candidate for scavenging peroxynitrite.