一株白僵菌对雄甾烯二酮转化产物的研究

利用白僵菌Beauveria bassiana HCCB00059对雄甾烯二酮（4AD）进行转化，对其主要产物进行分离纯化和结构鉴定，确认转化产生四个化合物，分别为：11-羟基-睾酮、6，11-羟基睾酮、6，11-羟基-雄甾烯二酮和11-羟基-18-氧杂D扩环雄甾烯二酮。     

1,3-二羰基化合物以Oxone氧化裂解为羧酸

在氮气中 ,1,3-二羰基化合物或 α-羟基酮的甲苯溶液先与草酸二乙酯、2 5 %甲醇钠于 35℃反应 3h,所得中间体与Na HCO3丙酮液剧烈搅拌并冷至 0℃ ,此浆状物与 Oxone(过硫酸氢钾 )的水溶液反应 15 m in,可得目的物。6例收率 84 %～ 97%。本法成功地应用于将黄体酮转化为 4 -雄甾烯 - 17β-羧酸1,3-二羰基化合物以Oxone氧化裂解为羧酸@沈蓓苓     

氧甲氢龙衍生物的合成

目的：设计合成氧甲氢龙的衍生物。方法：以3β-羟基-5α-雄甾烷-17-酮为原料经氧化开环、还原、缩合得到中间体17β-羟基-A-失碳-5α-雄甾烷-2-酮,此中间体与不同的酰氯反应生成的一系列C17位酰化产物再经过Baeyer -Villiger反应得到氧甲氢龙衍生物系列A;以3β-羟基-5α-雄甾烷-17-酮为原料与不同酰氯反应生成氧甲氢龙衍生物系列B;以3β-羟基-5α-雄甾烷-17-酮的酰化产物为原料经过Baeyer-Villiger反应得到氧甲氢龙衍生物系列C。结果与讨论 ：合成了3个系列22个未见报道的新化合物,目标化合物的结构均经H1-NMR、IR、MS谱确证。     

三种生物黄酮类化合物及其与棉酚相互作用抑制豚鼠肾脏11β—羟甾脱氢酶

目的:探讨三种生物黄酮类化合物在棉酚诱发低血钾中的作用.方法:从豚鼠肾脏制备11β-羟甾脱氢酶,NAD为辅酶,加入待测化合物,37℃反应一小时后提取甾体,反相高压液相测定酶活性,热辐射图像法分析药物相互作用.结果:所试生物黄酮类化合物均能抑制11β-羟甾脱氢酶,其IC_(50)(95％可信限)分别为:槲皮素164(7-341)μmol/L,桑色素 913(385-2173)μmol/L,柑桔素2193 (1114-4315)μmol/L.当11β-羟甾脱氢酶分别用槲皮素,红桔素,桑色素,柑桔素加上棉酚处理时,其C1值分别为:0.92、0.85、0.98和1.01,结论:三种生物黄酮类化合物与棉酚在抑制11β-羟甾脱氢酶中具有协同或相加作用.     

氢化可的松中间体-孕甾-4-烯-17α,21-二醇-3,20-二酮-21-醋酸酯的合成

目的:以雄烯二酮(AD)为原料合成氢化可的松中间体。方法:从AD出发,通过醚化保护,Wittig反应,KMnO4氧化,Py.SO3氧化合成氢化可的松中间体孕甾-4-烯-17α,21-二醇-3,20-二酮-21-乙酸酯。结果:C17位引入侧链基团。结论:该方法合理,合成路线短,反应条件温和,适宜工业化生产。     

非那雄胺的合成新法

以孕烯醇酮为原料先制得3-羰基-4-雄甾烯-17β-羰酸，将其与草酰氯反应，无需分离即与叔丁胺反应得17β-酰胺化合物，接头打开A环，再与氨反应闭环得4-氮杂甾体化合物，再经氢化和1，2-位脱氢制得非那雄胺。本法无需使用昂贵的2，2′-二吡啶二硫化物，更适于工业化生产，反应总收率16%。     

微生物3-甾酮-△1-脱氢酶的研究进展

3-甾酮-△^1-脱氢酶（KSDH）属于黄素蛋白酶类，位于细胞膜上，能在3-甾酮化合物的C1和C2之间引入双键，提高原有底物的抗炎活性，在甾体药物的生产上发挥着重要作用。文章对已报道的不同微生物来源的KSDH进行比较分析，着重介绍了关于KSDH基因表达和敲除方面的研究，并对该酶在甾体转化方面的应用做一简要总结。     

3,5-甾二烯化合物的合成及抗早孕活性

以18-甲基-17β-羟基-17α-乙炔基-雌甾-4-烯-3-酮(18-甲基炔诺酮),17β-羟基-17α-乙缺基-雌甾-4-烯-3-酮(炔诺酮),17β-羟基-17α-乙炔基-雄甾-4-烯-3-酮(妊娠素)和17a-羟基孕甾-4-烯-3,20二酮(17α-羟基黄体酮)为原料,经NaBH,还原、脱水、双键转位和酯化等反应合成一系列3,5-甾二烯化合物,用¹HNMR和MS证明了它们的结构。动物筛选结果表明,17β-丙酰氧基-17α-乙炔基-雌甾-3,5-二烯(IV_b2有明显的抗早孕活性。中断早期妊娠的作用似与其雌激素活性有关。     

远位功能化及其在甾体药物合成中的应用

本文综述了新近发展起来的远位功能化技术的原理及其在甾体药物合成中的应用,包括通过9-位选择性氢化引入11-羟基以及甾醇17位边链的切除等。     

细胞色素P450酶系介导的甾体羟化反应及其在分子水平上的研究进展

细胞色素P450单加氧酶系(cytochrome P450 monooxygenases,P450s)是主要位于某些细胞的内质网上的一个氧化酶系.P450酶系介导羟化反应是微生物甾体化合物转化反应中最重要的反应.本文概述了微生物细胞色素P450酶系,并注重综述了细胞色素P450酶系基因在转录水平调控、克隆表达以及在甾体转化应用、药物代谢等分子水平方面的研究进展.     

Discovery of nonsteroidal 17beta-hydroxysteroid dehydrogenase 1 inhibitors by pharmacophore-based screening of virtual compound libraries

17Beta-hydroxysteroid dehydrogenase type 1 (17beta-HSD1) plays a pivotal role in the local synthesis of the most potent estrogen estradiol. Its expression is a prognostic marker for the outcome of patients with breast cancer and inhibition of 17beta-HSD1 is currently under consideration for breast cancer prevention and treatment. We aimed to identify nonsteroidal 17beta-HSD1 inhibitor scaffolds by virtual screening with pharmacophore models built from crystal structures containing steroidal compounds. The most promising model was validated by comparing predicted and experimentally determined inhibitory activities of several flavonoids. Subsequently, a virtual library of nonsteroidal compounds was screened against the 3D pharmacophore. Analysis of 14 selected compounds yielded four that inhibited the activity of human 17beta-HSD1 (IC 50 below 50 microM). Specificity assessment of identified 17beta-HSD1 inhibitors emphasized the importance of including related short-chain dehydrogenase/reductase (SDR) members to analyze off-target effects. Compound 29 displayed at least 10-fold selectivity over the related SDR enzymes tested.     

Human microsomal carbonyl reducing enzymes in the metabolism of xenobiotics: well-known and promising members of the SDR superfamily

The best known, most widely studied enzyme system in phase I biotransformation is cytochrome P450 (CYP), which participates in the metabolism of roughly 9 of 10 drugs in use today. The main biotransformation isoforms of CYP are associated with the membrane of the endoplasmatic reticulum (ER). Other enzymes that are also active in phase I biotransformation are carbonyl reducing enzymes. Much is known about the role of cytosolic forms of carbonyl reducing enzymes in the metabolism of xenobiotics, but their microsomal forms have been mostly poorly studied. The only well-known microsomal carbonyl reducing enzyme taking part in the biotransformation of xenobiotics is 11β-hydroxysteroid dehydrogenase 1, a member of the short-chain dehydrogenase/reductase superfamily. Physiological roles of microsomal carbonyl reducing enzymes are better known than their participation in the metabolism of xenobiotics. This review is a summary of the fragmentary information known about the roles of the microsomal forms. Besides 11β-hydroxysteroid dehydrogenase 1, it has been reported, so far, that retinol dehydrogenase 12 participates only in the detoxification of unsaturated aldehydes formed upon oxidative stress. Another promising group of microsomal biotransformation carbonyl reducing enzymes are some members of 17β-hydroxysteroid dehydrogenases. Generally, it is clear that this area is, overall, quite unexplored, but carbonyl reducing enzymes located in the ER have proven very interesting. The study of these enzymes could shed new light on the metabolism of several clinically used drugs or they could become an important target in connection with some diseases.     

Inhibitors of 17beta-hydroxysteroid dehydrogenase type 1

Carcinogenesis of hormone-related cancers involves hormone-stimulated cell proliferation, which increases the number of cell divisions and the opportunity for random genetic errors. In target tissues, steroid hormones are interconverted between their potent, high affinity forms for their respective receptors and their inactive, low affinity forms. One group of enzymes responsible for these interconversions are the hydroxysteroid dehydrogenases, which regulate ligand access to steroid receptors and thus act at a pre-receptor level. As part of this group, the 17beta-hydroxysteroid dehydrogenases catalyze either oxidation of hydroxyl groups or reduction of keto groups at steroid position C17. The thoroughly characterized 17beta-hydroxysteroid dehydrogenase type 1 activates the less active estrone to estradiol, a potent ligand for estrogen receptors. This isoform is expressed in gonads, where it affects circulating levels of estradiol, and in peripheral tissue, where it regulates ligand occupancy of estrogen receptors. Inhibitors of 17beta-hydroxysteroid dehydrogenase type 1 are thus highly interesting potential therapeutic agents for the control of estrogen-dependent diseases such as endometriosis, as well as breast and ovarian cancers. Here, we present the review on the recent development of inhibitors of 17beta-hydroxysteroid dehydrogenase type 1 published and patented since the previous review of 17beta-hydroxysteroid dehydrogenase inhibitors of Poirier (Curr. Med. Chem., 2003, 10, 453). These inhibitors are divided into two separate groups according to their chemical structures: steroidal and non-steroidal 17beta-hydroxysteroid dehydrogenase type 1 inhibitors. Their estrogenic/ proliferative activities and selectivities over other 17beta-hydroxysteroid dehydrogenases that are involved in local regulation of estrogen action (types 2, 7 and 12) are also presented.     

Multiplicity of mammalian reductases for xenobiotic carbonyl compounds

A variety of carbonyl compounds are present in foods, environmental pollutants, and drugs. These xenobiotic carbonyl compounds are metabolized into the corresponding alcohols by many mammalian NAD(P)H-dependent reductases, which belong to the short-chain dehydrogenase/reductase (SDR) and aldo-keto reductase superfamilies. Recent genomic analysis, cDNA isolation and characterization of the recombinant enzymes suggested that, in humans, the six members of each of the two superfamilies, i.e., total of 12 enzymes, are involved in the reductive metabolism of xenobiotic carbonyl compounds. They comprise three types of carbonyl reductase, dehydrogenase/reductase (SDR family) member 4, 11beta-hydroxysteroid dehydrogenase type 1, L-xylulose reductase, two types of aflatoxin B1 aldehyde reductase, 20alpha-hydroxysteroid dehydrogenase, and three types of 3alpha-hydroxysteroid dehydrogenase. Accumulating data on the human enzymes provide new insights into their roles in cellular and molecular reactions including xenobiotic metabolism. On the other hand, mice and rats lack the gene for a protein corresponding to human 3alpha-hydroxysteroid dehydrogenase type 3, but instead possess additional five or six genes encoding proteins that are structurally related to human hydroxysteroid dehydrogenases. Characterization of the additional enzymes suggested their involvement in species-specific biological events and species differences in the metabolism of xenobiotic carbonyl compounds.     

Stereocontrolled syntheses for the six diastereomeric 1,2-dihydroxy-4,5-diaminocyclohexanes: PtII complexes and P-388 antitumor properties

Stereocontrolled syntheses for the six diastereomeric 1,2-dihydroxy-4,5-diaminocyclohexanes 3a-f from cyclohexene diamines cis-4 and trans-5 are described. Cbz-protected species cis-9 and trans-11, respectively, served as a source of stable Cbz-protected precursors to these cyclohexanediol diamines (CDD), which were liberated upon catalytic (H2, Pd/C) hydrogenation. Catalytic osmylation of 9 afforded a mixture of diastereomeric diols 13 and 14, which served as precursors to cis-anti-cis CDD 3b and cis-syn-cis CDD 3a, respectively, whereas osmylation of 11 yielded the expected single product 12, the precursor to cis-anti-trans CDD 3d. Epoxidation of olefins 9 and 11 afforded oxiranes 15 and 17, respectively, which upon acid-catalyzed hydrolysis produced the corresponding Cbz-protected diols 16 and 18, which served as precursors to CDD trans-anti-cis 3c, and trans-anti-trans 3e. Formation of diol 18 from oxirane 17 was accompanied by formation of 2-oxa-4-azabicyclo[3.3.1]nonan-3-one 19. CDD trans-syn-trans 3f was prepared from diol 12 via regioselective monoacetylation, yielding 22, followed by oxidation to afford ketone 24. Sodium borohydride reduction and acetylation produced diacetate precursor 26. PtIICl2 complexes of five of the diamines (3a-d,f) are described, and their activities were compared with cisplatin (1) by employing P-388 leukemia implanted CDF1 mice. The data indicate that stereochemistry of the amino groups on the cyclohexanediamine ligand modulate the expression of toxic effects, and depending upon hydroxyl and amino group stereochemistry, there is a marked effect on complex formation (e.g., Cl2PtII-3e) and solubility characteristics (e.g., Cl2PtII-3c). Acetylation of the hydroxyl functions in selected isomers (28a-c) rendered the PtII complexes inactive. A single-crystal X-ray structure of compound 3a was determined at room temperature and indicated the cis-syn-cis arrangement of the OH and NH2 groups.     

Molecular and structural aspects of xenobiotic carbonyl metabolizing enzymes. Role of reductases and dehydrogenases in xenobiotic phase I reactions

The major metabolic pathways involved in synthesis and disposition of carbonyl and hydroxyl group containing compounds are presented, and structural and functional characteristics of the enzyme families involved are discussed. Alcohol and aldehyde dehydrogenases (ADH, ALDH) participate in oxidative pathways, whereas reductive routes are accomplished by members of the aldo-keto reductase (AKR), short-chain dehydrogenases/reductases (SDR) and quinone reductase (QR) superfamilies. A wealth of biochemical, genetic and structural data now establishes these families to constitute important phase I enzymes.     

Novel benzofuran derivatives for PET imaging of beta-amyloid plaques in Alzheimer's disease brains

A novel series of benzofuran derivatives as potential positron emission tomography (PET) tracers targeting amyloid plaques in Alzheimer's disease (AD) were synthesized and evaluated. The syntheses of benzofurans were successfully achieved by an intramolecular Wittig reaction between triphenylphosphonium salt and 4-nitrobenzoyl chloride. When in vitro binding studies using AD brain gray matter homogenates were carried out with a series of benzofuran derivatives, all the derivatives examined displayed high binding affinities with K(i) values in the subnanomolar range. Among these benzofuran derivatives, compound 8, 5-hydroxy-2-(4-methyaminophenyl)benzofuran, showed the lowest K(i) value (0.7 nM). In vitro fluorescent labeling of AD sections with compound 8 intensely stained not only amyloid plaques, but also neurofibrillary tangles. The (11)C labeled compound 8, [(11)C]8, was prepared by reacting the normethyl precursor, 5-hydroxy-2-(4-aminophenyl)benzofuran, with [(11)C]methyl triflate. The [(11)C]8 displayed moderate lipophilicity (log P = 2.36), very good brain penetration (4.8%ID/g at 2 min after iv injection in mice), and rapid washout from normal brains (0.4 and 0.2%ID/g at 30 and 60 min, respectively). In addition, this PET tracer showed in vivo amyloid plaque labeling in APP transgenic mice. Taken together, the data suggest that a relatively simple benzofuran derivative, [(11)C]8, may be a useful candidate PET tracer for detecting amyloid plaques in the brains of patients with Alzheimer's disease.     

Purification and characterization of oxidoreductases-catalyzing carbonyl reduction of the tobacco-specific nitrosamine 4-methylnitrosamino-1-(3-pyridyl)-1-butanone (NNK) in human liver cytosol

1. Four enzymes were purified to homogeneity from human liver cytosol and were demonstrated to be responsible for carbonyl reduction of the tobacco-specific nitrosamine 4-methylnitrosamino-1-(3-pyridyl)-1-butanone (NNK). 2. Carbonyl reductase (EC 1.1.1.184), a member of the short-chain dehydrogenase reductase (SDR) superfamily, was compared with three isoenzymes of the aldo-keto reductase (AKR) superfamily in terms of enzyme kinetics, co-substrate dependence and inhibition pattern. 3. AKR1C1, 1C2 and 1C4, previously designated as dihydrodiol dehydrogenases (DD1, DD2 and DD4), showed lower K_m (0.2, 0.3 and 0.8?mm respectively) than did carbonyl reductase (7 mM), whereas carbonyl reductase exhibited the highest enzyme efficiency (V_max/K_m) for NNK. Multiplication of enzyme efficiencies with the relative quantities of individual enzymes in cytosol resulted in a rough estimate of their contributions to total alcohol metabolite formation. These were ~ 60% for carbonyl reductase, 20% each for AKR1C1 and 1C2, and 1% for AKR1C4. 4. Except for AKR1C4, the enzymes had a strong preference for NADPH over NADH, and the highest activities were measured with an NADPH-regenerating system. Carbonyl reductase activity was extensively inhibited by menadione, rutin and quercitrin, whereas medroxyprogesterone acetate, phenolphthalein and flufenamic acid were potent inhibitors of AKR1C1, 1C2 and 1C4. 5. In conclusion, cytosolic members of the SDR and AKR superfamilies contribute to reductive NNK detoxification in human liver, the enzymes responsible being carbonyl reductase and aldoketo reductases of the AKR1C subfamily.     

深海链霉菌Streptomyces somaliensis SCSIO ZH66ptm生物合成基因簇中orf7功能的探究

目的 探究深海链霉菌Streptomyces somaliensis SCSIO ZH66中编码多环特特拉姆酸大环内酰胺(polycyclic tetramate macrolactams,PTMs)类化合物 somamycin A～D 的生物合成基因簇ptm中orf7对该基因簇编码产物的影响.方法 采用PCR-tar...