新型含亲水基的噻唑烷-4-酮衍生物的合成及HIV逆转录酶抑制活性

在微波辐射条件下合成了系列C-2或N-3位含酯基的噻唑烷-4-酮衍生物,经水解或还原得到含亲水基如羧基、羟基的衍生物.化合物通过艾滋病毒逆转酶(HIV-RT)试剂盒(比色法)评价了其酶抑制活性.活性结果表明,部分化合物如8a,8b,9a,9b和14c能有效地抑制HIV逆转酶的活性.其中在N-3嘧啶环5位连有乙基的化合物8a和9a的活性最高,IC50值分别为3.02和3.06μmol·L-1.构效关系表明亲水性基团的引入对HIV逆转录酶抑制活性影响不大,而N-3位嘧啶基更有利于噻唑烷-4-酮抗HIV活性.     

熊果酸衍生物的合成及抗肿瘤血管生成活性

对熊果酸C28位与C3位进行结构修饰得到了24个衍生物, 并利用 1H NMR, 13C NMR, MS及HR-MS对这些化合物进行了结构表征. 进一步通过MTT法, 以内皮细胞HUVEC为主要模型, 研究了24个衍生物抗肿瘤血管生成的活性, 同时以A549, Bel-7402及MCF-7细胞为模型研究了上述衍生物对肿瘤细胞的抑制活性. 研究结果表明, 与熊果酸相比, 化合物5, 9, 12e和14e对HUVEC细胞有较好的选择性, 化合物12a和13h比熊果酸的抗肿瘤血管生成活性略高, 因此通过适当改变熊果酸C28位的结构可以提高其对内皮细胞HUVEC的选择性, 增强抗肿瘤血管生成活性. 本文结果表明, 熊果酸及其衍生物是潜在的具有抗肿瘤血管生成作用的先导化合物, 通过有效的结构优化可能得到新型的抗肿瘤血管生成的化合物.     

苯并咪唑并氮杂糖的结构修饰及其β-葡萄糖苷酶抑制活性

源于D-核糖的苯并咪唑并氮杂糖1和2具有良好的β-葡萄糖糖苷酶抑制活性,对其苯环部位结构修饰,通过Mitsunobu反应合成了30个新型苯环不同位置上含单取代基的苯并咪唑并氮杂糖稠合三环衍生物11a～11g, 12a～12g,13a～13h和14a～14h.测试了新合成化合物对β-葡萄糖糖苷酶(杏仁)的抑制活性.结果显示,化合物13e和13f与14f的混合物对β-葡萄糖糖苷酶(杏仁)表现出优越的酶抑制活性, IC50值分别为0.49和0.25μmol/L,活性高于阳性对照米格列醇的酶抑制活性.构效分析表明,稠合三环氮杂糖中的六元氮杂糖环形式有利于此类苯并咪唑并氮杂糖三环衍生物的β-葡萄糖苷酶抑制活性.苯环上3'或4'位连有给电基团,如甲基、甲氧基等,将极大地促进化合物的酶抑制活性.     

新型N-3位酰胺连噻唑烷-4-酮二芳基衍生物的设计合成及HIV逆转酶抑制活性

以氨基酸酯为原料,在微波辐射条件下合成了系列N-3位含酯基的噻唑烷-4-酮衍生物,经水解并酰胺缩合制备了N-3位酰胺键连接嘧啶胺的二芳基噻唑烷-4-酮衍生物.化合物通过人类免疫缺陷病毒(HIV)逆转酶(RT)试剂盒(比色法)评价了其酶抑制活性.活性结果表明,部分化合物如5bb,5bc,5cb和5cc能有效地抑制HIV逆转酶的活性,IC_(50)值分别为4.15,3.53,4.61和4.06μmol/L.构效关系表明N-3位2个碳的柔性侧链以及亲脂基如甲基的引入将有利于化合物的抗HIV逆转录酶活性.     

查尔酮Mannich碱衍生物的合成与AChE抑制活性研究

以柚皮苷为原料,经酸催化水解、O-甲基化或O-异戊烯基化反应、碱催化的开环反应合成了天然查尔酮卡瓦胡椒素A(1)和查尔酮异戊烯基醚衍生物2;然后以查尔酮1和2为底物,分别通过Mannich反应对其3'位进行了胺甲基化修饰,合成了14个未见文献报道的新型查尔酮Mannich碱衍生物3~16.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,并对所合成的查尔酮及其Mannich碱衍生物进行了乙酰胆碱酯酶(AChE)抑制活性测试,结果发现查尔酮Mannich碱衍生物3~5,9具有良好的AChE抑制活性.     

2-(2’,6’-二氯苯基)-1,3-噻唑烷-4-酮衍生物的微波促进合成及抗真菌、 抗肿瘤活性研究

利用微波促进的方法, 以2,6-二氯苯甲醛、胺和巯基乙酸为原料, 合成了系列N-3位不同取代基团的噻唑烷酮衍生物. 部分化合物在Lawesson试剂作用下, 合成了其系列噻唑烷4-硫酮衍生物. 所有化合物通过IR, 1H NMR, MS和元素分析等方法确定结构. 测试了化合物对黄瓜白粉病菌的抑制活性和对宫颈癌细胞的毒性作用, 部分化合物表现出较好的生物活性.     

6-(烷胺酰肼基)-1-氮杂苯并蒽酮衍生物的合成及生物活性研究

以对氯苯乙胺和邻苯二甲酸酐为原料,设计合成了一系列新的6位取代的1-氮杂苯并蒽酮衍生物.并对所合成衍生物的抑制乙酰胆碱酯酶、丁酰胆碱酯酶和乙酰胆碱酯酶诱导的Aβ聚集活性进行了评价.合成的衍生物表现出中等的胆碱酯酶抑制活性,大部分化合物的抑制IC50值处于微摩尔浓度水平.动力学研究表明,衍生物对乙酰胆碱酯酶的抑制类型属于非竞争性抑制.所有化合物表现出有意义的乙酰胆碱酯酶诱导的Aβ聚集抑制活性,其抑制率在35.2%~62.2%之间.而且,合成的18个新衍生物中有11个化合物能够透过血脑屏障进入中枢神经系统.     

4-(3-(4-羟基苯基) -3-氧代-1-芳基丙氨基)-N-(5-甲基异噁唑-3-基)苯磺酰胺的合成与抗糖尿病活性

由磺胺甲噁唑、对羟基苯乙酮和芳香醛反应直接合成了13个未见报道的β-氨基酮,反应选择性发生在羰基α位。产物结构通过¹H NMR、¹³C NMR、MS进行了表征。生物活性试验显示,低浓度范围,所得化合物不仅显示一定的蛋白质酪氨酸磷酸酶1B(PTP1B)和α-葡萄糖苷酶抑制活性,而且具有中等强度的过氧化物酶体增殖物激活受体反应元件(PPRE)的激动活性,8个化合物的激动活性超过40％,其中化合物11的活性达到72.7％。     

大黄素衍生物的合成及抗癌活性

通过对大黄素的C6位进行化学修饰, 设计合成了7个含氮杂环的大黄素衍生物和3个含季铵盐基团的大黄素衍生物. 通过红外光谱、 ¹H NMR和质谱表征了所制备化合物的结构, 并测试了它们对白血病细胞Molt-4和淋巴瘤细胞CA46的体外抑制活性. 其中化合物8, 9a+9b, 20a, 20b和20c均显示出比大黄素更高的抗癌活性, 表明苯并咪唑基团和季铵盐基团是大黄素提高抗癌活性的有效药效团.     

1,2,7,9-四取代去氢骆驼蓬碱衍生物的合成及体外抗肿瘤活性

为了寻找高效低毒的抗肿瘤候选化合物, 以去氢骆驼蓬碱为原料, 对β-咔啉环的2-,7-和9-位3个结构位点进行了结构改造, 合成了11个去氢骆驼蓬碱衍生物, 化合物的结构经核磁共振、 红外光谱、 质谱及元素分析确证. 采用四甲基偶氮唑盐(MTT)法初步测试了目标化合物体外抗肿瘤(Bel-7402, 786-0, BGC-823, A375, 769-P和MCF7)活性, 结果表明化合物4a, 4b, 8a和8b具有显著的体外抗肿瘤活性.     

Synthesis of new α-glucosidase inhibitors based on oleanolic acid incorporating cinnamic amides

A series of α-glucosidase inhibitors with the oleanolic acid core and different cinnamic amide ligands were designed and synthesized. Their preliminary structure-activity relationships were analyzed. In general, the compounds with 3,28-disubstituted oleanolic acid exhibited stronger activity than those 28-monosubstituted analogues, and variation of cinnamic amide substitution significantly affected α-glucosidase inhibition activities. Most of the compounds showed potent inhibitory activity against α-glucosidase with much greater efficacy than a typical α-glucosidase inhibitor, acarbose.     

基于咔唑的新型碳酰腙衍生物的合成及蛋白酪氨酸磷酸酶1B(PTP1B)抑制活性评价

合成出了一系列新型基于咔唑的单-/双-碳酰腙衍生物3和4.利用1H NMR、13C NMR、IR和元素分析对其进行了结构表征.评价了目标化合物对蛋白酪氨酸磷酸酶1B(PTP1B)的抑制活性,讨论了结构与活性的关系.实验结果显示,大部分化合物对PTP1B具有良好的抑制活性,其中1,5-双[(9-丁基-3-咔唑基)亚甲基]碳酰腙(4c)的抑制活性最高,IC50=(4.81±0.41)mmol/L,且活性高于对照药物齐墩果酸.对目标化合物1-[(9-庚基-3-咔唑基)亚甲基]碳酰腙(3f)和4c进行分子对接研究和密度泛函理论(DFT)计算.分子对接结果表明,化合物3f和4c结合到PTP1B酶由螺旋α3和α6形成的活性位点,与PTP1B酶通过氢键、极性、疏水和p-p等相互作用形成了稳定的复合物.     

Pycnalin, a new α-glucosidase inhibitor from Acer pycnanthum

A new compound, pycnalin (1), together with four known compounds, ginnalins A (2), B (3), C (4), and 3,6-di-O-galloyl-1,5-anhydro-D-glucitol (3,6-di-GAG) (5), were isolated from Acer pycnanthum. The structure of 1 was determined on the basis of 2D-NMR spectral data and synthesis of 1. Pycnalin (1) is the first 1,5-anhydro-D-mannitol linked to a gallic acid, while compounds 2-5 were 1,5-anhydro-D-glucitol linked to gallic acids. All compounds were tested in vitro for α-glucosidase inhibitory and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities. Pycnalin (1) exhibited moderate α-glucosidase inhibitory activity as well as free radical scavenging activity. Ginnalin A (2) and 3,6-di-GAG (5), which have two galloyl groups, exhibited potent α-glucosidase inhibition, compared to those of other compounds 1, 3, and 4 containing a galloyl group. These results suggest that α-glucosidase inhibition is influenced by the number of galloyl groups.     

Screening of hypoglycemic components in Platycladi Cacumen by phytochemical investigation,spectrum-effect relationship,and chemometric methods

In this work, the hypoglycemic components in Platycladi Cacumen, an essential traditional Chinese medicine, were evaluated by combining phytochemical investigation, spectrum-effect relationship analysis, and chemometric methods. The phytochemical studies on Platycladi Cacumen extract lead to the isolation of 21 potential bioactive compounds. The chromatographic fingerprints of Platycladi Cacumen samples were established by high-performance liquid chromatography. The hypoglycemic effects of Platycladi Cacumen samples were further evaluated by inhibition of α-glucosidase and detected by the high-performance liquid chromatography method. The spectrum-effect relationship study by bivariate correlations analysis and orthogonal partial least squares regression revealed that myricitrin (P9), quercitrin (P13), afzelin (P18), and amentoflavone (P24) were more relevant to the α-glucosidase inhibitory activity. The results of α-glucosidase inhibitory activity of 21 isolated compounds and molecular docking studies also indicated these flavonoids had potent α-glucosidase inhibitory activity. Collectively, the present study established the spectrum-effect relationship mode of Platycladi Cacumen and discovered the major hypoglycemic components, which provides a feasible method for screening bioactive components.     

Triterpenoids from the roots of Sanguisorba tenuifolia var. Alba

The ethyl acetate soluble fraction from the roots of Sanguisorba tenuifolia was found to have a hypoglucemic effect in alloxan-induced diabetic rats. Two new triterpenoids, identified as 2-oxo-3β,19α-dihydroxyolean-12-en-28-oic acid β-D-gluco-pyranosyl ester (1) and 2α,19α-dihydroxy-3-oxo-12-ursen-28-oic acid β-D-glucopyranosyl ester (4) were isolated from this fraction, along with thirteen known triterpenoids. Their structures were elucidated by chemical and spectroscopic methods. All these compounds demonstrated inhibitory activities against α-glucosidase with IC?? values in the 0.62-3.62 mM range.     

Chemical modification of oleanene type triterpenes and their inhibitory activity against HIV-1 protease dimerization

Oleanolic acid derivatives with different lengths of 3-O-acidic acyl chains were synthesized and evaluated for their inhibitory activity against HIV-1 protease. The lengths of the acidic chains were optimized to 6 and 8 carbons. Changing a 3-ester bond to an amide bond or dimerization of the triterpenes retained their inhibitory activity against HIV-1 protease. Introduction of an additional acidic chain to C-28 of oleanolic acid increased the inhibitory activity appreciably, though a derivative with only one acidic chain linked at C-28 also showed potent activity against HIV-1 protease. The inhibitory mechanism was proved directly by size exclusion chromatography to be inhibition of dimerization of the enzyme polypeptides. The ester bonds of the triterpene derivatives were found to be stable to lipase under mild alkaline conditions.     

Hepatoprotective and hepatotoxic actions of oleanolic acid-type triterpenoidal glucuronides on rat primary hepatocyte cultures

The protective effects of oleanolic acid-type saponins and their derivatives on in vitro immunological liver injury of primary cultured rat hepatocytes were studied. A known antihepatotoxic saponin (chikusetsusaponin IVa, 1) showed hepatoprotective activity in this model. Although a rhamnosyl derivative (2) of 1 similarly showed hepatoprotective activity, its prosapogenin (5) did not show any hepatoprotective activity. On the contrary, 5 exhibited cytotoxicity toward liver cells. In the absence of antiserum, monodesmosyl saponins showed hepatotoxicity, while the bisdesmosyl saponins except for 1, did not show such hepatotoxicity. In order to clarify the effects of the sugar residues at C-3 and C-28 responsible for hepatoprotective and hepatotoxic actions, oleanolic acid 3-O-glucuronide (2a) and oleanolic acid 28-O-glucoside (2b) were prepared and tested. 2b showed neither hepatoprotective action nor hepatotoxicity. In contrast, 2a was effective at 90 microM on hepatoprotection, although it showed strong hepatotoxicity. Oleanolic acid (2c) itself showed both hepatoprotective action and weak hepatotoxicity. Therefore, the hepatoprotective activity of these types of saponins could represent a balance between hepatoprotective action and hepatotoxicity.     

Antioxidant and α-Glucosidase Inhibitory Compounds of Centella Asiatica

Centella asiatica, as known as Pegagan was previously reported to have anti-hyperglycemic effects in animal diabetic model rats. However, its α-glucosidase activity in vitro assay not yet reported. Our goal in this study is to isolate and identify active compounds as α-glucosidase inhibitor and antioxidant from aqueous ethanol 70% (v/v) extract of C. asiatica. The extract was partitioned by n-hexane, EtOAc, and n-butanol sequentially. Among the fractions tested, EtOAc fraction was showed the highest antioxidant and α-glucosidase inhibitory activities with an IC₅₀ values of 45.42 and 73.17 μg/mL, respectively. The antioxidant activity was conducted by determination of DPPH radical scavenging activity, whereas α-glucosidase inhibitory activity was determined against yeast α-glucosidase. Furthermore, isolation of the ethyl acetate extract yielded two active compounds, which were identified as kaempferol (1) and quercetin (2). Both of the compounds showed good yeast α-glucosidase inhibitory activity with IC₅₀ values of 16.50 and 21.61 μg/mL, respectively. In addition those compounds also could scavenge DPPH radical activity with IC₅₀ values of 9.64 and 11.97 μg/mL, respectively. Due to its ability in reducing α-glucosidase activity and scavenging free radical activity, the C. asiatica appears to be a potential as a good resource for future development of antioxidant and antidiabetic drug.     

Synthesis and Anti-tumor Activity of Novel Amide Derivatives of Ursolic Acid

Ursolic acid was modified at C3 and C28 position to obtain fourteen derivatives including twelve novel compounds, and their chemical structures were characterized by IR, ^1H NMR and MS. Cell growth inhibitory effects of the derivatives against Hela cell were evaluated by MTT assay. All these derivatives were found to have stronger cell growth inhibitory than their parent compound, ursolic acid. The derivatives with a substituted acetyl group at C3 hydroxyl group show better activities than those with an unsubstituted hydroxyl group.     

A new flavone glucoside together with known ellagitannins and flavones with anti-diabetic and anti-obesity activities from the flowers of pomegranate (Punica granatum)

A new flavone glucoside tricetin 4′-O-β-glucopyranoside (1) and four known ellagitannins and flavones tricetin (2), luteolin (3), ellagic acid (4), and granatin B (5) were isolated from the flowers of Punica granatum L. (Lythraceae). Their structures were established by 1D and 2D NMR as well as mass spectrometry analyses. Among all tested compounds, tricetin (2) exhibited the strongest α-glucosidase inhibitory activity that was comparable to the anti-diabetic drug acarbose. Comparative structure-function analysis of tri-, tetra-, and pentahydroxy flavones [apigenin, luteolin (3), and tricetin (2), respectively] suggested that a greater number of hydroxyl groups on the flavone molecule enhanced its suppression of α-glucosidase, α-amylase, and lipase activities.