7 resultados para Cyclooxygenase (COX)-2

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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Background: Cyclooxygenase-2 (COX-2) plays essential roles in inflammation. Previous studies have suggested associations between prostaglandin-endoperoxide synthase 2 (PTGS2) polymorphisms and prostaglandins production in asthma. Objective: We have invest

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Cyclooxygenase-2 (COX-2, encoded by the gene prostaglandin-endoperoxide synthase 2, PTGS2) is a key enzyme in the conversion of arachidonic acid to prostaglandins. The prostaglandins produced by COX-2 are involved in inflammation and pain response in diff

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1-甲基-2-甲氧羰基-3, 6, 8-三羟基-7-甲氧基蒽醌是从唐菖蒲干球茎中分离到的具有环氧化酶-2选择性抑制活性的多取代蒽醌类化合物。本文试图合成该化合物,实现了其类似物的合成,同时发现了几个未见报道的反应。 1.通过Diels-Alder 反应合成了关键中间体——3-甲基-5-羟基-1, 2, 4-苯三甲酸三甲酯,1-COOMe选择性水解产物与1, 2, 3-三甲氧基苯进行分子间Friedel-Crafts反应的产物再进行分子内Friedel-Crafts反应得到了目标产物的类似物1-甲基-2-甲氧羰基-3-羟基-6,7,8-三甲氧基蒽醌(路线1)。目标产物及其它类似物的合成正在进行中。 2.以乙酰乙酸甲酯和巴豆醛为原料,经过Michael加成、分子内的Aldol反应、芳香化、选择性甲酰化和还原反应,得到关键中间体2-甲基-3-羟甲基-6-甲氧基苯甲酸甲酯及其衍生物。通过该化合物与3,4,5-三甲氧基苯甲酸甲酯进行Friedel-Crafts烷基化反应得到了多取代的二苯基甲烷衍生物,拟进一步关环合成目标化合物(路线2)。 3.发现邻甲氧基苯甲酸甲酯中酯甲基可以被正丁基锂和仲丁基锂中烷基交换生成相应的酯,反应的机理不明确。当使用叔丁基锂时,得到的是邻甲氧基苯基叔丁酮,这个方法可以用来合成芳基叔丁酮类化合物。 4.以2-苄氧基-6-甲基苯甲酸甲酯为原料进行氯甲基化反应时,以苯和二氯乙烷作溶剂,发生了苄基的迁移和芳环的偶联,分别得到2,2'-二甲基-3,3'-二甲氧羰基-4,4'-二羟基联苯和2,2'-二甲基-3,3'-二甲氧羰基-4,4'-二羟基-5,5'-二苄基联苯。这是对称联苯合成的新方法。 5.水杨酸羟基邻对位的选择性甲酰化可以分别通过水杨酸和水杨酸甲酯用HMTA/CF3COOH来实现。 6.Lewis酸催化3,4,5-三甲氧基苄醇环化成1, 2, 3, 6, 7, 8, 11, 12, 13-nonamethoxyl-10,15-dihydro-5H-trbibenzo [a, d, g] cyclononene (NDTC),产率(54%)高于已有方法(12%)。 Methyl 3,6,8-trihydroxy-7-methoxy-1-methylanthraquinone-2-carboxylate is a new COX-2 selective inhibitor isolated from Gladiolus gandavensis. Two strategies were investigated to synthesis this compound, in which some important reactions were discovered. 1. The key intermediate 5-hydroxy-3-methylbenzene-1,2,4-tricarboxylic acid 2,4-dimethyl ester was prepared via Diels-Alder reaction followed by selective hydrolysis of 1-COOMe. This compound was coupled with 1,2,3-trimethoxybenzene and the product undergo intramolecular Friedel-Crafts reaction to give methyl 3-hydroxy-5,6,7-trimethoxy-1-methylanthraquinone-2-carboxylate (1st route). The target compound and other analogues are being prepared with the same procedure. 2. The key intermediates methyl 3-hydroxymethyl-6-methoxy-2-methylbenzoate and its derivatives were prepared starting from crotonaldehyde and methyl acetoacetate via Michael addition, intramolecular aldol reaction, aromatization, formylation and reduction. The intermediates were coupled respectively with derivatives of gallic acid to give polysubstituted diphenylmethane. However, attempts to cyclize these compounds to the target compounds and analogues were not successful (2nd route). 3. In the process for ortho-lithiation of methyl 2-methoxybenzoate, the substrate converted respectively to n-butyl 2-methoxybenzoate and sec-butyl 2-methoxybenzoate when n-BuLi and sec-BuLi were used. However, tert-BuLi reacted with methyl 2-methoxybenzoate afford 2-methoxyphenyl tert-butyl ketone, which could be used to synthesize aryl tert-butyl ketones. 4. The transformtion of methyl 2-benzoxy-6-methylbenzoate to dimethyl 4,4'-dihydroxy-2,2'-dimethylbiphenyl-3,3'-dicarboxylate in benzene, and dimethyl 5,5'-dibenzyl-4,4'-dihydroxy-2,2'-dimethylbiphenyl-3,3'-dicarboxylate in 1,2-dichloroethane in the presence of ZnCl2 provides a new method for the synthesis of symmetric biphenyl. 5. The formylation of salicylic acid at C-5 and methyl 2-hydroxybenzoate at C-3 could be regioselectively realized by using HMTA/CF3COOH. 6. Racemic 1, 2, 3, 6, 7, 8, 11, 12, 13-nonamethoxyl-10, 15-dihydro-5H-trbibenzo [a, d, g] cyclononene was prepared via Lewis acids catalyzed trimerization of 3, 4, 5-trimethoxylbenzyl alcohol with yield (54%) higher than the reported procesure (12%).

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非甾体类抗炎药(NSAIDs)在治疗炎症、疼痛及发烧等病症时发挥着重要的作用[1],但是,传统的NSAIDs对消化道及肾有毒副作用.1971年Vane[2]发现了NSAIDs作用于环氧合酶(COX),并且影响前列腺素(PG)的合成;1991年simmens等[3]和Herschman等[4]发现环氧合酶包含两种同工酶COX-1和COX-2,COX-1发挥生理性管家功能;COX-2为诱导型,在正常组织内活性极低,当受到某些细胞因子、促有丝分裂物质和内毒素刺激时,大量表达,相应引起致炎介质的增加,使炎症加重.

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In our previous work, bone cell networks with controlled spacing and functional intercellular gap junctions had been successfully established by using microcontact printing and self assembled monolayers technologies [Guo, X. E., E. Takai, X. Jiang, Q. Xu, G. M. Whitesides, J. T. Yardley, C. T. Hung, E. M. Chow, T. Hantschel, and K. D. Costa. Mol. Cell. Biomech. 3:95-107, 2006]. The present study investigated the calcium response and the underlying signaling pathways in patterned bone cell networks exposed to a steady fluid flow. The glass slides with cell networks were separated into eight groups for treatment with specific pharmacological agents that inhibit pathways significant in bone cell calcium signaling. The calcium transients of the network were recorded and quantitatively evaluated with a set of network parameters. The results showed that 18 alpha-GA (gap junction blocker), suramin (ATP inhibitor), and thapsigargin (depleting intracellular calcium stores) significantly reduced the occurrence of multiple calcium peaks, which were visually obvious in the untreated group. The number of responsive peaks also decreased slightly yet significantly when either the COX-2/PGE(2) or the NOS/nitric oxide pathway was disrupted. Different from all other groups, cells treated with 18 alpha-GA maintained a high concentration of intracellular calcium following the first peak. In the absence of calcium in the culture medium, the intracellular calcium concentration decreased slowly with fluid flow without any calcium transients observed. These findings have identified important factors in the flow mediated calcium signaling of bone cells within a patterned network.

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非甾体类抗炎药(NSAIDs)是临床较常用的处方药,是高效的止痛、退热和抗炎药。NsADs有广泛的临床适应证,尤其适用于各种急、慢性关节炎,软组织风湿症、运动性损伤、头痛、痛经、拔牙后痛以及癌性疼痛等。因此,NsAIDs一直是世界上处方量最大的药物之一,包括我国在内的各国NSAIDs消耗量都呈明显上升趋势。仅疼痛控制部分,预计2007年就将达到300亿美元[l]。但是,大多数NSAIDs,尤其是我国目前使用的NSAIDs,都有较大的毒性和副作用。最新的分子生物学实验证明,各种NSAIDs起治疗作用的基础是通过抑制环氧合酶(cox),阻断致炎介质前列腺素类化合物的合成。环氧合酶至少包括两种同功酶(可能还有未被发现的新的亚类型),COX-1和COX-2。COX-1主要发挥生理性管家功能;COx-2主要为诱导型,在正常组织内活性极低,当受到某些细胞因子、促有丝分裂物质和内毒素刺激时大量表达,相应引起致炎介质的增加,使炎症加重。这些区别为设计兼具高抗炎活性和低毒性的药物提供了可能。阿司匹林是最早获得应用的NSAIDs,随后又出现一批其它NSADOs,最近美国FDA批准上市的罗非考昔,西乐葆是较好的COX-2选择性抑制剂,但是售价过于昂贵,从费用上考虑较难维持长期服用。至今我国还没有具有自主知识产权的COX-2特异性NSAIDs,服用的NSAIDs中,国外更新淘汰多年的毒副作用较大的药物仍占有较大比重,所以开发具有我们自主知识产权的新型NSAIDs迫在眉睫。鉴于COX-1,COX-2酶晶体结构明确,NSAIDs筛选模型确定,尤其是我国传统的中医药对炎症的独特认识,所以,凭借现代医学和化学知识,结合中国传统的中医药知识开发具有我们自主知识产权的新型NSAIDs是切实可行的。在研究过程中我们发现,在中国传统的中医药体系里,冰片是一种独特的药物,其主要成分为结构明确的龙脑、异龙脑。中医文献对其性质和应用详细的记载表明,其不仅广泛地用于抗风湿,而且其性质符合现代药物概念中的“靶向药物”概念。所以,如果合理设计使龙脑负载有抗炎结构化合物,可能会明显改善原药物的COX-2选择性,从而开发一种或几种COX-2特异性抑制剂。据此,又参考COX-2酶晶体结构,设计合成了其他结构的可能具有抗炎活性的药物分子。小茵香醇是龙脑和异龙脑的同分异构体和结构类似分子,我们选择该分子代替龙脑和异龙脑与布洛芬结合,并进行了活性测试和筛选,以深人了解该类分子。(1)设计并合成了含龙脑、异龙脑和小茵香醇结构的分子。相应结构见Tablel。(2)因为该类分子具有比较高的位阻,所以反应惰性较大,经过实验发现,在丁基锂/四氢吠喃反应体系或二环己基碳二亚胺仁甲氨基毗咙反应体系条件下,反应能够顺利进行。其中,二环己基碳二亚脚二甲氨基毗陡反应体系产率稍高。(3)针对几个主要反应详细探讨了分离纯化条件,为将来的放大实验或规模化制备提供了条件,并对所有产品进行了详细的结构表征。(4)通过“药物对小鼠腹腔巨噬细胞生成COX-1和COX-2的抑制作用”实验,对所获得的化合物进行了初步的活性评价,并得出如下结果:(a)在所设计的分子中,化合物3和化合物8分子表现出一定的COX-2选择性,其IC50COX-1/ IC50COX-2的比值分另为6.663和6.835,稍优于目前使用的第二代NSAIDs。见第七章Tablel,Table 2 and Figurel。(b)在所设计的分子中,化合物13,即布洛芬小菌香醇酷表现出最好的选择性;IC50COX-1/IC50COX-2比值为21.006,普遍超出目前使用的大部分NSAIDs,如果经过进一步的分子设计或修改有可能获得更好的结果。(c)化合物13与化合物9和化合物10相比较,选择性明显更好。即小茵香醇醋比龙脑酷和异龙脑醋表现出更好的靶向性。(d)从得到的结果可以看出,龙脑所负载的分子的选择性普遍比异龙脑要强,对于阿司匹林表现的尤为明显。(e)在中医药的文献和典籍中,关于小茵香醇性质和应用的记载很少,我们的研究结果表明它可能具有潜在的还不为我们所了解的特殊性质,我们的研究也可能会促进对该化合物的研究。(f)以佐剂关节炎模型对乙酰水杨酸龙脑醋进行了活性评价。

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We report here the investigation of a novel description of specificity in protein-ligand binding based on energy landscape theory. We define a new term, intrinsic specificity ratio (ISR), which describes the level of discrimination in binding free energies of the native basin for a protein-ligand complex from the weaker binding states of the same ligand. We discuss the relationship between the intrinsic specificity we defined here and the conventional definition of specificity. In a docking study of molecules with the enzyme COX-2, we demonstrate a statistical correspondence between ISR value and geometrical shapes of the small molecules binding to COX-2. We further observe that the known selective (nonselective) inhibitors of COX-2 have higher (lower) ISR values. We suggest that intrinsic specificity ratio may be a useful new criterion and a complement to affinity in drug screening and in searching for potential drug lead compounds.