核磁共振光譜探討玉米赤黴烯酮毒素與環糊精之作用

Interaction between Zearalenone and Cyclodextrin-A Nuclear Magnetic Resonance Study

萬耀宗(Yao-Tsung Wan)

指導教授 ： 錢偉鈞

朝陽科技大學/理工學院/應用化學系/碩士(2010年)

摘要

玉米赤黴烯酮毒素結構因具備螢光發光的要素當與環糊精結合時能增加其螢光強度，此一特性可應用鑑定黴菌毒素改善偵測極限之用。本文以核磁共振光譜技術針對黴菌毒素玉米赤黴烯酮與三類環糊精形成內包複合物進行探究及比較，以滴定實驗中共振訊號之變化判斷主客體分子間的結合部位，以NOEs測量內包複合物主客體分子相近質子間之距離。結合常數則根據玉米赤徽烯酮在水溶液及各環糊精環境下所測得之擴散係數計算而得。實驗結果顯示α-CD與玉米赤徽烯酮並無結合的明顯證據。而玉米赤黴烯酮則以苯環區域嵌入β-CD的孔洞之中，結合常數為100 M-1，在γ-CD的環境下，玉米赤黴烯酮以苯環區域進入環糊精之空腔孔洞，與β-CD比較，毒素更深入γ-CD的孔洞，其結合常數為61 M-1，顯示結合程度稍弱。毒素與β-CD及γ-CD形成內包複合物為一自發性程序。以核磁共振實驗所測得之距離限制進行分子模擬可獲得玉米赤黴烯酮和β-CD及γ-CD形成內包複合物之分子模型。能量計算結果顯示，玉米赤黴烯酮與環糊精結合過程中以疏水性為主要之驅動力，環糊精孔洞大小亦具有調整結合部位與結合強度之影響。

關鍵字

分子模擬 ； 玉米赤黴烯酮 ； 環糊精 ； 內包複合物 ； 核磁共振光譜儀

並列摘要

Cyclodextrin (CDs) have enhance fluorescence of hydrophobic fluorophores. This property has proven useful in inproving the detection limits in the analysis of mycotoxins. The inclusion complex interaction between zearalenone and α-CD、β-CD、γ-CD have been investigated by NMR spectroscopy. The 1H NMR spectra provide direct evidence of interaction between guest and host molecules. The closely related protons in space between zearalenone and CD molecules can be identified by the NOEs. Based on a two-state-model, the association constants of mycotoxin to different CSs are determined by monitoring the change of self-diffusion coefficient (Ds) of zearalenone from aqueous solution into CD environment. The Ds values are measured by pulsed-field-gradient NMR techniques. No evident interaction between zearalenone and α-CD. For β-CD, the aromatic region of toxin molecule embedded inside the cavity of cyclodextrin with Ka is 100M-1. For γ-CD, the guest molecule almost penetrate the host molecule, and the Ka is 61 M-1. The formation of zearalenone-CD complex is a spontaneous process. The mycotoxin-CD inclusion complex is simulated using NMR constraints. Hydrophobicity is the major factor in the toxin-CD recognition process which is also triggered by the cavity size of host molecules.

並列關鍵字

zearalenone ； cyclodextrin ； inclusion complex ； molecular modeling ； NMR

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