薯蓣皂苷元A环和F环的结构改造及其抗肿瘤活性初探

目的提高薯蓣皂苷元类衍生物的抗肿瘤活性以及进一步研究其构效关系。方法基于薯蓣皂苷元结构,运用Autodock 4.2进行对接设计,合成了一系列全新A环、F环结构改造的氨基酸酰胺,内酰胺杂环薯蓣皂苷元类衍生物。采用MTT法对人肝癌细胞HepG-2、人恶性黑色素瘤细胞A375和人肺癌细胞A549进行体外抗肿瘤活性实验。结果合成13个新化合物,结构经1HNMR、13CNMR确定,体外抗肿瘤活性结果表明化合物8～13具有一定活性。结论化合物8～13都具有一定的体外抗肿瘤活性,化合物13的药理学活性与阳性对照品紫杉醇活性相近。     

薯蓣皂苷元抗肿瘤衍生物的设计、合成与抗肿瘤活性

薯蓣皂苷元对A375、K562等细胞株具有抑制生长并诱导其凋亡的作用。其作用靶点之一是线粒体中的Bcl-2亚家族蛋白。本文以Bcl-2为靶点,运用Autodock设计并合成了一系列全新的薯蓣皂苷元衍生物,希望完善相关化合物的构效关系及提高其抗肿瘤活性。MTT法体外抗肿瘤活性研究结果表明,所设计的化合物大多对K562、A375、A549等3种肿瘤细胞株有较好的抑制作用,而对H293、L02等2种正常细胞株无明显作用。其中,化合物1、6～8对K562表现出了较好的活性(IC50值为1.96～4.35μmol.L-1)。     

抗肿瘤薯蓣皂苷元衍生物的设计与合成(Ⅰ)

目的 针对抗肿瘤活性,设计、合成薯蓣皂苷元衍生物并研究其体外抗肿瘤活性.方法 基于作用机制并运用Autodock进行目标分子辅助设计.以薯蓣皂苷元为原料,与氯乙酸缩合,得中间体(Ⅰ)后,再与杂环(哌啶、吗啉、哌嗪)或取代杂环(哌嗪)反应制得化合物Ⅱ～Ⅵ;以薯蓣皂苷元为原料,将其F环开环得到中间体(Ⅶ)后,再与不同的疏水性脂肪酸、芳香酸或酚缩合,制备了化合物Ⅷ～Ⅺ.采用MTT法对人恶性黑色素瘤细胞A375、人肺腺癌细胞A549、人肝癌细胞HepG-2进行体外抗肿瘤活性试验.结果 制备的化合物中,除化合物Ⅶ外,其余10个是新化合物,其结构经1HNMR、13CNMR确证.结论 薯蓣皂苷元衍生物的初步体外活性测试均表现出良好的抗肿瘤活性,其中,化合物Ⅳ、Ⅵ的抗肿瘤活性与阳性对照1-(3β-薯蓣皂苷元)-3-苄基咪唑溴盐相当.     

薯蓣皂苷元衍生物的制备及其抗肿瘤活性

目的 设计、合成薯蓣皂苷元衍生物并研究其体外抗肿瘤活性.方法 以薯蓣皂苷元为原料,与不同的L-氨基酸缩合,合成了6个化合物(Ⅰ～Ⅵ);与1,2,3-三氮唑和1,2,4-三氮唑偶联合成了2个中间体(Ⅶ,Ⅷ);再分别与不同的苄溴化合物反应得到一系列的盐(Ⅸ～Ⅻ).结果 合成的化合物中,除化合物Ⅴ外,其余11个是新化合物.结论 所合成的化合物结构经1HNMR、13CNMR确证.采用噻唑蓝(MTT)法测定了部分化合物的体外抗肿瘤活性.所测化合物都有良好的抗肿瘤活性,其中,化合物Ⅵ的抗肿瘤活性与阳性对照1-(3β-薯蓣皂苷元)-3-苄基咪唑溴盐相当.     

薯蓣皂苷元衍生物的抗肿瘤活性研究

目的研究薯蓣皂苷元衍生物在体外的抗肿瘤活性。方法采用MTT法对人恶性黑色素瘤细胞A375、人肺腺癌细胞A549、人肝癌细胞HepG-2及人慢性髓原白血病细胞株K562进行体外抗肿瘤活性试验。结果薯蓣皂苷元衍生物对4个肿瘤细胞株A375、A549、K562、HepG-2具有不同程度的抗肿瘤活性。结论绝大部分薯蓣皂苷元衍生物对4个肿瘤细胞株有较好的抗肿瘤活性,IC50值都低于30μmol.L-1。化合物22对细胞株A375的IC50=4.48μmol.L-1,化合物9、10对细胞株K562的IC50分别为2.51、2.38μmol.L-1;显示其抗肿瘤活性与对照化合物1-(3β-薯蓣皂苷元)-3-苄基咪唑溴盐相当。     

薯蓣皂苷元抗肿瘤衍生物的设计和合成(Ⅱ)

目的 合成薯蓣皂苷元衍生物并进行其体外抗肿瘤活性的研究.方法运用Autodock进行目标分子辅助设计.薯蓣皂苷元通过Mitsunobu反应合成1-(3α-薯蓣皂苷元)-1,2,3-三氮唑和1-(3α-薯蓣皂苷元)-1,2,4-三氮唑两个中间体,再分别与不司的溴代物反应得到一系列的盐.采用MTT法对人恶性黑色素瘤细胞A3...     

薯蓣皂苷元及其衍生物的构效关系研究进展

目的对近年来薯蓣皂苷元及其衍生物的构效关系研究进展进行综述,为薯蓣皂苷元的进一步研究提供思路。方法查阅了近10年关于薯蓣皂苷元衍生物研究的中外文献资料,对其构效关系进行了比较全面地综述。结果许多国内外学者针对不同生理活性对薯蓣皂苷元进行结构修饰,开发出一批具有高效低毒的先导化合物。结论薯蓣皂苷元衍生物具有良好的开发前景,应加强其衍生物与构效关系的研究。     

薯蓣皂苷元衍生物与M3受体的分子对接研究

目的研究薯蓣皂苷元衍生物与M3受体相互作用可能的构效关系,为薯蓣皂苷元舒张平滑肌的结构改造提供更多的理论基础。方法运用AutoDock4.0研究薯蓣皂苷元衍生物与M3受体的分子对接,并分析了对接结果与薯蓣皂苷元衍生物对离体豚鼠气管平滑肌舒张活性的结果,对接模型中的M3受体分子模型为以牛视紫红质的晶体结构为模板同源建模搭建的人M3受体的三维结构模型。结果薯蓣皂苷元衍生物与M3受体的对接结果与离体豚鼠气管平滑肌舒张的活性结果有一定联系。结论薯蓣皂苷元衍生物Ⅰ～Ⅴ的舒张活性有在一定范围内随碳链增长而提高的趋势;芳香酯类(Ⅵ～Ⅸ)的舒张活性可能与苯环取代基的供电性有关;带苯环的支链酯类(Ⅹ～Ⅺ)的位阻可能对舒张活性影响较大。因此,薯蓣皂苷元衍生物与M3受体的对接对其进一步的修饰有一定的指导作用。     

Molecular docking study of diosgenin derivatives and M3 receptor

目的 研究薯蓣皂苷元衍生物与M3受体相互作用可能的构效关系,为薯蓣皂苷元舒张平滑肌的结构改造提供更多的理论基础.方法 运用AutoDock4.0研究薯蓣皂苷元衍生物与M3受体的分子对接,并分析了对接结果与薯蓣皂苷元衍生物对离体豚鼠气管平滑肌舒张活性的结果,对接模型中的M3受体分子模型为以牛视紫红质的晶体结构为模板同源建模搭建的人M3受体的三维结构模型.结果 薯蓣皂苷元衍生物与M3受体的对接结果与离体豚鼠气管平滑肌舒张的活性结果有一定联系.结论 薯蓣皂苷元衍生物Ⅰ～Ⅴ的舒张活性有在一定范围内随碳链增长而提高的趋势;芳香酯类(Ⅵ～Ⅸ)的舒张活性可能与苯环取代基的供电性有关;带苯环的支链酯类(Ⅹ～Ⅺ)的位阻可能对舒张活性影响较大.因此,薯蓣皂苷元衍生物与M3受体的对接对其进一步的修饰有一定的指导作用.     

薯蓣皂苷元衍生物的合成及其抗血栓形成活性

目的设计合成薯蓣皂苷元衍生物,并评价其体内抗血栓形成活性.方法以薯蓣皂苷元为先导物,经过酯化等反应得到薯蓣皂苷元酯类衍生物,选择动静脉旁路血栓形成模型,评价体内抗血栓形成活性.结果合成了6个目标化合物,结构经过1H-NMR、13C-NMR、MS确证.抗血栓形成活性筛选结果显示,目标化合物3β-薯蓣皂苷元丁二酸单酯具有较...     

薯蓣皂苷下调ABCC1表达对人肝癌细胞HepG2/ADM耐药的影响

目的:探究薯蓣皂苷对人肝癌细胞HepG2/多柔比星(ADM)耐药性的影响及其可能的作用机制。方法:采用含0,10,20,30,40,50μmol·L^-1薯蓣皂苷的培养液培养HepG2、HepG2/ADM细胞,CCK法检测细胞增殖抑制率;MTT检测薯蓣皂苷对HepG2/ADM细胞、HepG2细胞半抑制浓度(IC50)值的影响;流式细胞术检测HepG2、HepG2/ADM细胞摄取ADM的能力。薯蓣皂苷联合ABCC1抑制剂处理HepG2/ADM细胞,MTT检测细胞IC50值变化;流式细胞术检测细胞摄取ADM的能力、细胞凋亡情况,免疫印迹法检测细胞人多药耐药相关蛋白1(ABCC1)、半胱天冬酶(caspase-3)、B淋巴细胞瘤-2(bcl-2)、Bcl-2相关X蛋白(Bax)蛋白表达情况。结果:HepG2/ADM细胞中ABCC1蛋白表达显著高于HepG2细胞(P<0.05)。薯蓣皂苷0~30μmol·L^-1对HepG2/ADM细胞、HepG2细胞毒性小。随着薯蓣皂苷处理浓度的升高,HepG2/ADM细胞IC50值均降低,摄取ADM量明显升高,具有剂量依赖性(P<0.05)。薯蓣皂苷联合ABCC1抑制剂处理HepG2/ADM细胞后能够进一步降低细胞IC50,提高细胞ADM摄取量,加速细胞凋亡,上调caspase-3、Bax蛋白表达,下调ABCC1、bcl-2蛋白表达(P<0.05)。结论:薯蓣皂苷能够逆转HepG2/ADM细胞耐药性,逆转效果与作用剂量相关,其机制可能与下调ABCC1表达,诱导细胞凋亡有关。     

Pro-apoptotic activity of imidazole derivatives mediated by up-regulation of <Emphasis Type="Italic">Bax</Emphasis> and activation of CAD in Ehrlich Ascites Tumor cells

Summary In this study we report that, imidazole derivatives can induce apoptosis in Ehrlich ascites tumor (EAT) cells, which is clearly evident from annexin-V staining, flow cytometric analysis of cell cycle phase distribution and DNA fragmentation. Delineating further into molecular mechanisms leading to apoptosis of EAT cells, we observed that imidazole derivatives induce tumor cell death by the up-regulation of proto-oncoprotein Bax, release of cytochrome c from the mitochondria which activates caspase-3 and activated caspase-3 activates CAD (Caspase Activated DNase) causes DNA fragmentation. The status of Bcl-2 remains unaltered in EAT cells, and the under expression of Bcl-2 and up-regulation of Bax resulted in the increase of Bax: Bcl-2 ratio suggesting that Bcl-2 family involved in the control of apoptosis. These results suggest a further possible clinical application of imidazole derivatives as pro-apoptotic agent in association with conventional chemotherapeutic agents.     

Mechanisms involved in the vasodilator effect induced by diosgenin in rat superior mesenteric artery

The aim of this study was to investigate the vasorelaxant effect induced by diosgenin in superior mesenteric rings. In rings pre-contracted with phenylephrine (10 microM), diosgenin caused concentration-dependent relaxations [EC(50) = (3.3 +/- 1.2) x 10(- 4)M, E(max) = 94.2 +/- 2.6 %]. Vascular relaxation induced by diosgenin was significantly inhibited after removal of the endothelium (E(max) = 46 +/- 8.8%, p < 0.001) or after pre-treatment of the rings with N-nitro-L-arginine methyl esther (l-NAME) 100 or 300 microM (E(max) = 35.3 +/- 4%; 28.1 +/- 3.3%, respectively, p < 0.001), atropine 1 microM (E(max) = 24.6 +/- 3.4%, p < 0.001), hydroxocobalamin 30 microM (E(max) = 54.0 +/- 9.6%, p < 0.001), 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ) 10 microM (E(max) = 46.0 +/- 8.0%, p < 0.001) or indomethacin 1 microM (E(max) = 22.6 +/- 11.8%, p < 0.001). Vasorelaxation evoked by diosgenin was significantly inhibited after pre-treatment of preparations with both selective and non-selective inhibitors of large conductance Ca(2+)-activated K(+) (BK(Ca)) channels, iberiotoxin 100 nM or tetraethylammonium (TEA) 1mM, respectively (E(max) = 62.5 +/- 9.1%; 65.7 +/- 1.1%, p < 0.001). Conversely, in endothelium-denuded vessels, none of BK(Ca) channel blockers modified the relaxant effect induced by diosgenin. In mesenteric endothelial cells loaded with FURA-2 diosgenin was able to increase intracellular calcium concentrations, which were significantly decreased by atropine 1 microM. In addition, in isolated mesenteric rings, diosgenin induced marked increase in nitric oxide (NO) levels, which was completely abolished after functional endothelium removal. The results obtained here demonstrated that diosgenin-induced relaxation appears to involve endothelial muscarinic receptor activation with increase in intracellular calcium concentrations and consequent release of endothelium-derived relaxing factors (EDRFs), mainly NO and cyclooxygenase derivatives, which activate BK(Ca) channels. Nevertheless, further studies are necessary to clearly elucidate residual endothelium-independent relaxation induced by diosgenin.     

Diosgenin induces apoptosis in HeLa cells via activation of caspase pathway

AIM: To investigate the mechanism of diosgenin-induced HeLa cell apoptosis. METHODS: HeLa cell growth was measured by MTT method. Apoptosis was detected by electron microscopy and agarose gel electrophoresis. Ratio of apoptotic cells was measured by APO-BRDU kit. Cell cycle distribution and changes of mitochondrial membrane potential were monitored by flow cytometry. Caspase activities were assayed by caspase apoptosis detection kit. Western blot analysis was used to evaluate the level of mitochondrial Bcl-2 expression. RESULTS: Diosgenin inhibited HeLa cell growth. HeLa cells treated with diosgenin showed typical characteristics of apoptosis including the morphological changes and DNA fragmentation. Caspase family inhibitor (z-VAD-fmk), caspase-9 inhibitor (Ac-AAVALPAVLLALLAPLEHD-CHO), and caspase-3 inhibitor (z-DEVD-fmk) partially prevented diosgenin-induced apoptosis, but not caspase-8 inhibitor (z-IETD-fmk) and caspase-10 inhibitor (z-AEVD-fmk). Diosgenin caused reduction of mitochondrial membrane po     

Improvement of Diosgenin Yield from Dioscorea deltoidea Plant Cell Cultures by Use of a Non-Traditional Hydrolysis Method

The attractiveness of fermentor cultures of DIOSCOREA DELTOIDEA Wall. (Dioscoreaceae) as a source of diosgenin has been greatly improved by switching away from the traditional product recovery method that has been used in all previous studies. By using a known but little-used hydrolysis method involving 2N H (2)SO (4) in 70% isopropanol rather than using 2N aqueous HCl, diosgenin was found to be a growth-associated product instead of a non-growth-associated product as was formerly thought. This is an important improvement from a biotechnological standpoint because it means that diosgenin can be obtained directly from growth-phase tissue and that a non-growth phase is unnecessary. The reason that switching hydrolysis methods has this impact is that the non-traditional method gives high diosgenin yields from a broader group of steroidal glycosides. During the non-growth phase, steroidal glycosides were found to spontaneously change from furostanol saponins to spirostanol saponins. Whereas the nontraditional hydrolysis method gives high diosgenin yields from both types, the traditional method gives high yields only from the latter type.     

Cytotoxicity of the phytosterol diosgenin and its derivatives in rat cultured hepatocytes and V79 fibroblasts

In this work, the cytotoxic effects of some spirostane derivatives were examined in cultured hepatocytes and V79 fibroblasts using different viability assays. The derivatives were obtained by modifying the A and B rings of diosgenin. Diosgenin and its derivatives were more toxic in V79 fibroblasts (IC50 40-300 microM) than in hepatocytes (IC50 280-1000 microM). Inhibition of cytochrome P450IIIA in cultured hepatocytes by incubation with 1 mM cimetidine did not alter the toxicity of these compounds in these cells. These observations suggest that other pathways of detoxification may be involved in hepatocytes. In conclusion, the compounds studied merit investigation for their potential pharmacological and industrial applicability.     

薯蓣皂苷元的提取工艺比较

目的:比较薯蓣皂苷元的提取工艺.方法:把常规提取方法和超临界萃取技术提取的薯蓣皂苷元利用高效液相色谱法进行含量测定,计算薯蓣皂苷元产率比较提取工艺.结果:常规提取法薯蓣皂苷元产率为0.622%,超临界CO2萃取法薯蓣皂苷元产率为1.226%.结论:超临界CO2萃取技术能显著提高薯蓣皂苷元的收率且缩短提取时间.