氮唑类抗真菌药物药效构象及其与酶活性位点对接

目的：研究氮唑类抗真菌药物与其受体蛋白活性位点相互作用机理。方法：用随机构象搜寻和分子动力学模拟退火法确定１５个４种不同类型的氮唑类抗真菌药物最低能量构象;用活性类似物法限定药物分子药效基团之间的距离,搜寻到各化合物药效构象;将各化合物药效构象对接到白色念珠菌羊毛甾醇１４α去甲基化酶活性位点中。结果：４种结构类型的氮唑类药物在酶活性位点中有相似的对接位置;真菌和哺乳动物的活性位点结构特异性的残基分布在Ｆ螺旋Ｃ端、β６１和β６２区中;氮唑类抗真菌药物共同的卤代芳环结构落入相同的疏水空穴中,其中Ｙ１３２的侧链羟苯基结构可与抑制剂卤代芳环形成电子迁移复合物。结论：对接结果与已知ＳＡＲ分析结论相符,阐明了氮唑类药物与活性位点的氨基酸残基作用方式,探讨结构选择性药物的结构需求。     

Kudzu root: traditional uses and potential medicinal benefits in diabetes and cardiovascular diseases

Kudzu root (Gegen in Chinese) is the dried root of Pueraria lobata (Willd.) Ohwi, a semi-woody, perennial and leguminous vine native to South East Asia. It is often used interchangeably in traditional Chinese medicine with thomson kudzu root (Fengen in Chinese), the dried root of P. thomsonii, although the Chinese Pharmacopoeia has separated them into two monographs since the 2005 edition. For more than 2000 years, kudzu root has been used as a herbal medicine for the treatment of fever, acute dysentery, diarrhoea, diabetes and cardiovascular diseases. Both English and Chinese literatures on the traditional applications, phytochemistry, pharmacological activities, toxicology, quality control and potential interactions with conventional drugs of both species have been included in the present review. Over seventy phytochemicals have been identified in kudzu root, with isoflavonoids and triterpenoids as the major constituents. Isoflavonoids, in particular puerarin, have been used in most of the pharmacological studies. Animal and cellular studies have provided support for the traditional uses of kudzu root on cardiovascular, cerebrovascular and endocrine systems, including diabetes and its complications. Further studies to define the active phytochemical compositions, quality standards and clinical efficacy are warranted. Strong interdisciplinary collaboration to bridge the gap between traditional medicine and modern biomedical medicine is therefore needed for the development of kudzu root as an effective medicine for the management of diabetes and cardiovascular diseases.     

The imidazoline-like drug S23515 affects lipid metabolism in hepatocyte by inhibiting the oxidosqualene: lanosterol cyclase activity

Imidazoline-like drugs are centrally-acting antihypertensive agents that inhibit the activity of the sympathetic nervous system by interacting with the alpha2-adrenoreceptor and also with a non-adrenergic imidazoline binding site called the imidazoline 1 receptor. Recently, these molecules were proposed to play an additional role in cardiovascular diseases by acting on glucose and lipid metabolism. We used S23515, a potent imidazoline-like molecule acting selectively on blood pressure through the imidazoline 1 receptor, to decipher the effects of these drugs on lipid metabolism. We found that S23515 inhibited specifically and dose-dependently cholesterol synthesis in cultured rodent and primate hepatocytes. This hypocholesterolemic effect was likely due to the inhibition of the oxido:lanosterol cyclase (OSC), a rate-limiting enzyme in the cholesterol biosynthetic pathway. Partial OSC inhibition induced by S23515 led to the generation of 24(S),25-epoxycholesterol, a potent ligand for the liver X receptor (LXR). Furthermore, S23515 increased in human macrophages the expression of both ABCA1 and G1, the 2 ATP binding cassette transporters, which play a pivotal role in the reverse cholesterol transport. Thus, these results suggest that S23515, and potentially other imidazoline-like drugs, could exert hypolipidemic effects in addition to their hypotensive activities.     

抗真菌药物靶标及其抑制剂的研究进展

目的综述抗真菌药物靶标及其抑制剂的研究进展。方法本文结合自身研究工作,分析近5年文献,总结抗真菌药物靶标及其抑制剂的最新进展。结果β-1,3-葡聚糖合成酶、羊毛甾醇14α-去甲基化酶、N-肉豆蔻酰基转移酶和分泌型天冬氨酸蛋白酶是目前研究最为集中的抗真菌药靶,其抑制剂显示了良好的新药开发前景。结论优化现有药物化学结构和发现全新作用机制的先导化合物,对研发新一代抗真菌药物具有重要意义。     

地锦草有效部位对红色毛癣菌羊毛甾醇生物合成的影响

目的:研究地锦草有效部位对红色毛癣菌中羊毛甾醇含量的影响。方法:样品在24孔板中培养七天,经皂化提取、甲醇定容后,采用高效液相色谱法进行定量测定。结果:地锦草有效部位浓度最小为32μg/ml能使真菌中的羊毛甾醇含量发生蓄积(P<0.01),在32μg/ml～128μg/ml之间有明显的剂量依赖性。结论:地锦草有效部位可使真菌中羊毛甾醇蓄积,导致细胞膜麦角甾醇的合成受阻来发挥其抗真菌作用。     

气质联用法定量分析白念珠菌中甾醇含量

目的 建立气质联用法(GC-SIM-MS)测定白念珠菌中羊毛甾醇和麦角甾醇的含量.方法 白念珠菌经离心、皂化、提取出甾醇部分后溶解于环己烷中,采用HP-5毛细管柱进行气相色谱分析,柱温:程序升温150～ 320℃,起始温度150℃,按10℃/min升至300℃,再按20℃/min升至320℃;检测器温度270℃;进样口温度270℃;载气:氦气1 ml/min;质谱检测器:EI离子源,电力电压70 eV;SIM Scan;the selected ions:3.00～ 17.50 min,275,386;17.50 ～ 19.00 min,363,396;19.00～ 30.00min,411,426;进样量:lμl;无分流比.结果 羊毛甾醇和麦角甾醇线性关系良好(r分别为0.999 8和0.999 5),回收率在91.2％ ～117.3％ (RSD＜2.5％),最低检测限分别为18.29 ng/ml和68.13 ng/ml,日内及日间精密度良好(RSD均小于1.2％).结论 本方法准确、灵敏、专属性强,结果可靠,为抗真菌药物研究提供了有力的工具.     

气质联用技术定量研究TTS-12对白念珠菌甾醇合成途径的影响

目的:研究天然产物TTS-12对白念珠菌甾醇生物合成途径的影响。方法:用微量液基稀释法测定TTS-12对不同真菌的最低抑菌浓度。采用气相色谱-质谱法测定白念珠菌经TTS-12作用前后麦角甾醇、羊毛甾醇的含量。结果:TTS-12对白念珠菌、新型隐球菌具有抑制作用。对照组白念珠菌麦角甾醇、羊毛甾醇含量为(53·2±4·8)%、(3·5±0·6)%;TTS-12作用后,麦角甾醇、羊毛甾醇含量为(5·6±0·8)%、(16·5±3·2)%。结论:TTS-12可能作用于白念珠菌细胞膜麦角甾醇合成途径,抑制麦角甾醇的生物合成而发挥抗真菌活性。     

衍生化—毛细管气相色谱法定量分析白念珠菌中甾醇含量

目的:建立衍生化-毛细管气相色谱法测定白念珠菌中羊毛甾醇和麦角甾醇等甾醇的含量。方法:白念珠菌经破碎、离心、皂化、提取出甾醇部分后再经1-三甲基甲硅烷咪唑(TMSI)硅烷化后,其TMSI衍生物采用HP 50毛细管柱进行气相色谱分析,柱温:程序升温150～290℃,起始温度150℃,按15℃·min~(-1)升至290℃恒定;检测器温度280℃;进样口温度270℃。柱头压35kPa;载气:氮气,流速82mL·min~(-1);每次进样量:1μL;分流比为100:1。结果:在0.1862～1.862mg·mL~(-1)衍生物的氯仿溶液范围羊毛甾醇和麦角甾醇线性关系良好(r分别为0.9996和 0.9969),回收率分别大于97％和93％(RSD<5％),最低检测限分别为1.86ng·mL~(-1)和2.54ng·mL~(-1),日内精密度良好(RSD均在5％以内)。结论:本方法准确、灵敏、专属性强,结果可靠,为抗真菌药物研究提供了有力的工具。     

2-甲基-2-取代-7-羟基-2,3-二氢-4H-1-苯骈吡喃-4-酮及其衍生物的合成和抗真菌活性研究

目的：对自行设计的抗真菌先导化合物进行衍生物合成和抗真菌活性研究,以验证设计思想,检验模建结果的可靠性。方法：设计合成18个化合物,所有目标化合物经元素分析、¹HNMR谱和红外光谱确证,部分化合物还进一步用¹³CNMR谱、MS-EI谱和高分辨质谱确证。用8种人类致病真菌对所有目标化合物测试体外最小抑菌浓度值。结果：合成的18个化合物中,14个(JS1b～d,JS2a～d,JS3a～b,JS4a～d和JS5c)为新化合物。结论：对所合成的化合物进行抗真菌活性测试,结果表明设计合成的衍生物的抗真菌活性变化规律与设计思想吻合,从配体角度验证了模建的靶酶三维结构的可靠性,检测了活性位点力场的分布。     

特苄康唑对真菌麦角甾醇生物合成的影响

 目的：研究新化合物特苄康唑对真菌麦角甾醇生物合成的影响。方法：用薄层色说谱语扫描法考察真菌经不同浓度特苄康唑作用后,其麦角甾醇和羊毛甾醇的含量变化。结果：特苄康唑能使真菌中的麦角甾醇含量下降,羊毛甾醇含童增加,两者的 含量变化均有明显的剂量依赖性;同浓度时特苄康唑对真菌生长繁殖和麦角甾醇生物合成的抑制作用无显著差异。结论：特苄康唑是通过抑制真菌的麦角甾醇生物合成而发挥其高效抗真菌活性的,为羊毛甾醇14a-去甲基化酶抑制剂。