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    题名: 黃酮類抗氧化物之QSAR分析
    其它题名: Quantitative structure-activity relationship of flavonoid antioxidants
    作者: 張詠昇;Chang, Yeong-sheng
    贡献者: 淡江大學化學學系碩士班
    王伯昌;Wang, Bo-cheng
    关键词: 定量結構活性關係;半經驗計算方法;黃酮類化合物;抗氧化劑;丙二醛;Quantitative structure-activity relationship;semi-empirical;Flavonoids;antioxidant;malonaldehyde
    日期: 2005
    上传时间: 2010-01-11 02:47:38 (UTC+8)
    摘要: 鑒於藥物開發須耗費大量人力、物力以及財力,一種藉由理論與實際結合的藥物開發方法-定量結構活性關係 ( Quantitative Structure-Activity Relationship,QSAR ) 分析,透過藥物化學與計算化學在生技領域的整合,縮短整個藥物開發的流程。本篇研究對於黃酮類化合物分子,進行量子化學半經驗方法的理論計算,並對其抗氧化能力進行QSAR分析,期望能夠發揮電腦模擬技術和演算能力,於分子結構作修飾,找出活性更佳之分子。
    針對黃酮類化合物之分子結構,以量子化學半經驗 ( semi-empirical ) 計算方法,對118個黃酮類化合物分子作幾何結構最佳化的計算,並根據文獻已知的結構參數,將環上的羥基取代基作為關鍵的資訊參數;另外思考量子化學方面參數的引入,最後以多元線性回歸分析探討參數對於活性的影響。分析的結果分為兩部分作深入討論:1. 於結構參數部分,黃酮類分子A 環上的羥基取代,於靠近色原酮位置的取代,分子內氫鍵的形成,對於抗氧化活性之加成性有顯著功效;C 環4 位置的羥基取代,以及3 , 4 位置羥基所形成的氫鍵,此種結構對於活性皆有所助益。2. 在能量參數部分,電子組態能、靜電能及鍵能與活性有良好的相關性質。靜電能、鍵能對活性呈現明顯之負相關,其中鍵能對於活性的影響可以用線性分析得到很好的結果。
    經由QSAR 模型之建立,我們可以明確地規範出影響黃酮類分子抗氧化活性之因素。利用結構參數及能量參數資訊上的彙整,思考如何改善黃酮類化合物的結構,增進其對於脂質過氧化的最終產物丙二醛 ( malonaldehyde,MDA ) 的抑制能力。最後藉由8個測試組的黃酮類分子作活性之預測,其結果也與我們所預期的相符合。因此使用本研究之QSAR 模型來預測新分子的抗氧化活性,將可以得到合理之結果。
    Because of the large cost of people, materials, and money in the drug design process, a new investigation – Quantitative Structure-Activity Relationship ( QSAR ) , was used in this study. Recently, computer-aided drug design has emerged as a powerful technique in drug discovery process. Modern QSAR analysis developed using molecular structure descriptors and regression analysis techniques have found wide utility and acceptance. It was our aim to reduce the time of discovering process as well as help us to design better structures of flavonoids and more efficient antioxidants.
    A series of 118 flavonoid molecules were employed in all the calculations. All molecular structures were optimized at semi-empirical ( PM3 ) level. By use of structural , electronic energy, electrostatic energy, and bond energy as descriptors, the regression analysis was performed using. As the result, we suggested that the substituent position of the hydroxy group on the position 5 and 8 of the A ring could make an important role in the antioxidant property. Another key point might be the hydroxy group on the position 3 and 4 of the C ring. Besides, it had been shown good correlation between bond energy and antioxidant property. All the three energies ( electronic energy, electrostatic energy, and bond energy ) also affected the activity and helped us to construct the final QSAR model.
    It was clear from our QSAR analysis that all the descriptors involved encode very specific information about what factors affect the antioxidant properties of the flavonoids. Thus we could design more efficient antioxidants by using this model.
    显示于类别:[化學學系暨研究所] 學位論文

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