18β-甘草次酸A环开环衍生物的合成及抗肿瘤活性

采用化学方法在18β-甘草次酸A环上进行结构修饰,合成了一系列新颖的A环具有不同官能团的开环衍生物.初步研究了它们对人体肝癌细胞HepG-2的体外细胞毒活性,结果表明,羟基的数目和位置对抑制HepG-2细胞增殖起着重要的作用.     

18β-甘草次酸吡啶酰胺衍生物的定向合成及其初步抗癌活性研究

以18β-甘草次酸和2,5-吡啶二甲酸为起始原料,便捷地合成了5种含吡啶杂环多酰胺结构的18β-甘草次酸衍生物.全部新合成化合物的结构由1H NMR,13C NMR及HRMS等方法得到了确证.通过四甲基偶氮唑盐(MTT)法对所有新合成化合物的抑制人宫颈癌Hela细胞活性进行了体外评价,初步发现目标系列化合物对人宫颈癌Hela细胞均具有细胞毒活性,能够有效抑制Hela细胞增殖、诱导其凋亡,IC50最小值仅为0.02μmol·L-1,均优于临床抗肿瘤药物阿糖胞苷.     

β-环糊精与18-冠-6超分子包合物的形成、结构和热降解

采用元素分析、¹H核磁共振谱(¹H NMR)和电喷雾电离质谱研究了两个大环主体分子β-环糊精(β-CD)和18-冠-6 (18C6), 结果显示, 二者通过简单地混合形成了计量比为1:1的超分子包合物18C6-β-CD. 基于二维核磁共振谱(ROESY)的分析, 提出了分子间相互作用的可能位点: 18C6更倾向于驻留在β-CD的小口端. 用热重分析和气相色谱飞行时间质谱比较了包合作用前后热降解过程包括降解度和降解产物的差异性, 研究表明, 18C6的存在促使β-CD提前分解, 同时, 由于分子间相互作用, 导致二者分解产物中大碎片的相对含量大幅减小. 这些结果显示, 一个柔性大环分子18C6和一个刚性大环分子β-CD之间通过分子组装可以形成超分子包合物.     

新型18β-甘草次酸氨基二硫代甲酸酯衍生物的合成及抗癌活性研究

以18β-甘草次酸为原料首先经简单酰胺化反应方便地得到18β-甘草次酸哌嗪,再与二硫化碳、碳酸钾以及不同结构卤代烃"一锅煮"法快速、高效地合成了10种含氨基二硫代甲酸酯结构的新型甘草次酸酰胺类衍生物,通过IR,1H NMR,13C NMR和HR-MS对所有新化合物进行了结构确证;并以四甲基偶氮唑盐比色法(MTT)法评价了该类化合物对人肝癌细胞株SMMC-7721的细胞毒活性.初步生物活性研究结果表明,该类化合物具有明显的抑制人肝癌细胞增殖、诱导其凋亡的细胞毒活性,给药72 h,半抑制浓度IC50最优值仅为14.42μg/mL.     

高效液相色谱法同时测定甘草酸及其发酵产物

建立甘草酸发酵液中甘草酸及其发酵产物乌拉尔甘草皂苷乙、3-O-β-D-葡萄糖醛酸-24-OH-18β-甘草次酸、单葡萄糖醛酸甘草次酸、18α-单葡萄糖醛酸甘草次酸和甘草次酸的RP-HPLC含量测定方法,为单葡萄糖醛酸甘草次酸的生产工艺研究及产品质量控制提供方法学基础。采用Kromasil C18(250 mm×4.6 mm,5μm)色谱柱,以甲醇(B)-1%乙酸溶液(A)为流动相进行梯度洗脱:0 min,63%B;40 min,66%B;50 min,75%B;70 min,90%B;80 min,90%B。体积流速:1.0 mL/min;进样量:10μL;柱温:25℃;检测波长:254 nm。甘草酸、乌拉尔甘草皂苷乙、3-O-β-D-葡萄糖醛酸-24-OH-18β-甘草次酸、单葡萄糖醛酸甘草次酸、18α-单葡萄糖醛酸甘草次酸和甘草次酸的线性范围分别为11.25~180.0μg/mL(r=0.9986);3.031~96.99μg/mL(r=0.9978);2.595~83.00μg/mL(r=0.9999);62.50~2000μg/mL(r=0.9999);11.25~180.0μg/mL(r=0.9980);1.560~50.00μg/mL(r=0.9992);平均回收率(n=9)分别为98.3%,101.2%,98.4%,101.9%,101.7%,97.42%,RSD分别为2.5%,1.4%,0.96%,2.8%,0.73%,0.32%。     

甘草次酸精氨酸盐的波谱学表征

甘草次酸是甘草的主要活性物质之一,具有抗炎、抗溃疡、抗病毒、防治肿瘤等多种药理活性[1-1]。本文利用精氨酸与甘草次酸成盐,一方面改善了甘草次酸在水中的溶解度,可提高其生物利用度;另一方面可降低血管痉挛的发生[3],从而提高用药安全性。本文主要报道该化合物的波谱学特征。1实验部分1.1甘草次酸精氨酸盐的合成在反应瓶中加入等物质量的18β-甘草次酸(0·95g)和L-精氨酸(0·35g),用80%乙醇75mL溶解,室温下搅拌反应2h,减压除溶剂并干燥,得白色疏松粉末状物,即为甘草次酸精氨酸盐(GA-Arg)。其熔点为184℃~186℃,结构如图1所示。图1甘草…     

α-氯丙酸乙酯对映体与β-环糊精的主客体相互作用

运用量子力学PM3方法模拟α-氯丙酸乙酯((R/S)-ECPA)与β-环糊(β-CD)的主客体相互作用, 探讨(R/S)-ECPA在β-CD上的手性识别机理. 结果表明, (R/S)-ECPA对映体与β-CD形成稳定结合物的结合方式完全不同, (R)-ECPA位于β-CD空腔宽口端, 形成缔合物; (S)-ECPA插入β-CD空腔内形成包结物. 而且, (S)-ECPA与β-CD的结合稳定能低于(R)-ECPA与β-CD的结合稳定能. 在(R/S)-ECPA与β-CD结合物中, (R/S)-ECPA中的手性碳接近葡萄糖单元的C2和C3. (R/S)-ECPA与β-CD之间的手性识别与葡萄糖单元的C2和C3所提供的手性环境和(R/S)-ECPA与β-CD结合的紧密程度密切相关.     

新型甘草次酸酰胺杂环衍生物的合成及其抗结核活性

以18β-甘草次酸为原料,经过多步酰胺化反应合成了14个含不同杂环的新型甘草次酸多酰胺衍生物(11a～11n),收率78.6%～92.3%,其结构经1H NMR,13C NMR和IR表征。其中11i和11n的初步抑菌活性测试结果表明,杂环酰胺基团对甘草次酸衍生物的抗结核活性具有明显的增效作用。     

Fusarisetin A的合成研究进展

Fusarisetin A是一个结构新颖的tetramic acid类天然产物,它具有6-6-5-5-5并环骨架和10个手性中心.它对腺泡的形成以及细胞迁移和入侵有显著的抑制活性,表明此化合物具有选择性抑制肿瘤细胞转移的潜质.该综述总结了fusarisetin A自发现一年多时间来的合成进展情况.     

齐墩果酸的结构修饰和α-葡萄糖苷酶抑制活性

以天然五环三萜类化合物齐墩果酸为原料, 通过氧化、酯化、环合和曼尼希等反应, 对A环2, 3位和28位进行结构修饰, 设计合成了16个衍生物; 通过理化性质、质谱和核磁数据确定了化合物结构. 对合成的衍生物进行了体外α-葡萄糖苷酶抑制活性筛选, 结果表明, 受试化合物在200 μg/mL浓度下显示出不同程度的酶抑制活性. 初步构效关系分析表明, 28位游离羧基是活性必需基团, 3位羟基或相应的氢键供体取代基有利于提高活性.     

11-脱氧甘草次酸衍生物的合成

本文报道了具有潜在药理活性和应用前景的11-脱氧甘草次酸酯、11-脱氧甘草次酸盐的合成方法。     

Derivatization,molecular docking and in vitro acetylcholinesterase inhibitory activity of glycyrrhizin as a selective anti-Alzheimer agent

Acetylcholinesterase inhibitors (AChE-Is) increase both level and duration of action of acetylcholine (ACh); thus, alleviate symptoms of Alzheimer’s disease (AD). Glycyrrhizin, is the main active compound in liquorice root. Its aglycone, glycyrrhetinic acid, has shown several beneficial pharmacological activities. This study reports the synthesis and screening of a series of glycyrrhetinic acid analogs as AChE-Is. Fourteen derivatives were prepared, of which five derivatives are recorded as new viz., 3-phenyl-carbamoyl-18β-glycyrrhetinic acid (J9), 3-acetyl-18β-glycyrrhetinic-30-anilinamide (J10), 3-acetyl-18β-glycyrrhetinic-30-ethanolamide (J11), 3-acetyl-18β-glycyrrhetinic-30-n-butylamide (J12) and 18β-glycyrrhetinic acid-30-prenyl ester (J14), in addition to nine known derivatives (J1-J8 & J13). Compounds J12, J11, J0 and J3 showed remarkable AChE-I activity with IC₅₀ values of 3.43, 5.39, 6.27 and 8.68 μM, respectively. These results are in full agreement with the docking study. The active compounds were non-cytotoxic to normal cells (WI-38).     

Synthesis of hairpin siRNA using 18β-glycyrrhetinic acid derivative as a loop motif

We synthesized a new phosphoramidite building block from 18β-glycyrrhetinic acid. This compound was introduced in the middle of the palindromic oligonucleotides and they formed hairpin structure. This 18β-glycyrrhetinic acid derivative excellently performed its role as hairpin loop. These hairpin ODNs had higher T_m values than the natural one and formed stable hairpin structure without any structural distortion. We found that stability of hairpin ODNs was changed according to the length of hairpin stem and modified hairpin ODNs, which had longer than seven base pair stem, were more stable than natural one based on T_m values. The shRNAs bearing similar modified loop were also synthesized. These modified shRNAs could suppress their target gene expression without losing their RNAi efficiency.     

Synthesis and antitumor activity of novel podophyllotoxin derivatives

In order to find compounds with superior bioactivity and overcoming multidrug resistance,a novel series of 4β-N-substituted podophyllotoxin derivatives were synthesized and evaluated as potential antitumor agents.Seven novel podophyllotoxin derivatives were synthesized by linking-4β-amino-4-deoxypodophyllotoxin with alcohols through maleic acid and tested against K562 and K562/A02 using MTT assay in vitro.     

Three sesquiterpene compounds biosynthesised from artemisinic acid using suspension-cultured cells of Averrhoa carambola (Oxalidaceae)

A new sesquiterpene glycoside, artemisinic acid 3-β-O-β-D-glucopyranoside (3, 31.24%) and other two biotransformation products, 3-β-hydroxyartemisinic acid (2, 36.69%) and 3-β-hydroxyartemisinic acid β-D-glucopyranosyl ester (4, 7.03%), were biosynthesised after artemisinic acid (1) was administered to the cultured cells of Averrhoa carambola. The three biotransformation products were obtained for the first time by using the suspension-cultured cells of A. carambola as a new biocatalyst system, and their structures were identified on the basis of the physico-chemical properties, NMR and mass spectral analyses. The results indicate that the cultured cells of A. carambola have the abilities to hydroxylate and glycosylate sesquiterpene compounds in a regio- and stereoselective manner. Furthermore, the anti-tumour activity of compounds 3 and 4 was evaluated against K562 and HeLa cell lines. Compound 4 showed strong activity against HeLa cell line, with the IC?? value of 0.56?μmol?mL?1.     

Grafting of 18β-Glycyrrhetinic Acid and Sialic Acid onto Chitosan to Produce a New Amphipathic Chitosan Derivative: Synthesis,Characterization, and Cytotoxicity

Chitosan is the only cationic polysaccharide found in nature. It has broad application prospects in biomaterials, but its application is limited due to its poor solubility in water. A novel chitosan derivative was synthesized by amidation of chitosan with 18β-glycyrrhetinic acid and sialic acid. The chitosan derivatives were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, and measurement of the zeta potential. We also investigated the solubility, cytotoxicity, and blood compatibility of chitosan derivatives. 18β-glycyrrhetinic acid and sialic acid could be grafted onto chitosan molecular chains. The thermal stability of the synthesized chitosan derivatives was decreased and the surface was positively charged in water and phosphate-buffered saline. After chitosan had been modified by 18 β-glycyrrhetinic acid and sialic acid, the solubility of chitosan was improved greatly in water and phosphate-buffered saline, and percent hemolysis was <5%. Novel amphiphilic chitosan derivatives could be suitable polymers for biomedical purposes.     

LC–MS/MS analysis of puerarin and 18β-glycyrrhetinic acid in human plasma after oral administration of Samso-eum and its application to pharmacokinetic study

The aim of this study was to confirm pharmacokinetic screening of multiple components in healthy Korean subjects after oral administration of Samso-eum and perform quantitation of active components in the human plasma. Thirteen potential bioactive components [puerarin (PRR), daidzin, nodakenin, ginsenoside Rb1, 18β-glycyrrhetinic acid (18β-GTA), 6-shogaol, naringin, glycyrrhizin, hesperidin, platycodin D, naringenin, hesperetin, and 6-gingerol] were screened based on literature. The results showed that three analytes (daidzin, naringenin, and hesperetin) were detected in trace amounts. In addition, PRR and 18β-GTA were detected in human plasma after the oral administration of Samso-eum. In this study, a liquid chromatography–electrospray ionization-tandem mass spectrometry method was validated for the simultaneous determination of PRR and 18β-GTA in human plasma. This was the first study to evaluate pharmacokinetics of PRR and 18β-GTA after the usual oral dose of Samso-eum (30 g containing 102.48 mg PRR, 48.18 mg glycyrrhizin) in human subjects.     

Chemical Constituents from Alafia Barteri Oliv. Leaves with Cytotoxic Activity

Methanol extract of Alafia barteri leaves showed cytotoxic activity on leukaemia carcinoma K562, and hepatic liver cancer cells WRL (IC₅₀ values 193.1 and 225.0 μM respectively). Isolation of the extract gave ursane triterpenoid, 28‐acety‐urs‐5,20‐dien‐2β,3β,24α‐triol, 1 , together with undecanol, 2 , stigmasterol, 3 and octadecanoic acid, 4 . The structures of these compounds were identified by spectroscopic analysis, including MS, 1D and 2D NMR, and supported with literature data. Compound 1 exhibited cytotoxic activity against K‐562 at 50 and 100 μM concentrations with IC₅₀ 74.22 μM, while compounds 2 , 3 and 4 showed low inhibition of WRL, MCF‐7 and COLO cell lines.