生物鹼與氟離子之交互作用力探討

Abstract

Palmatine與Berberine為含有四級氮（quaternary nitrogen）的生物鹼（Alkaloid），可嵌入去氧核醣核酸（Deoxyribonucleic acid，簡稱DNA）結構中的AT-rich minor groove。由於所衍生的產物具有敏光性，可於紫外光照射下將叁重態氧（3O2）轉變為單重態氧（1O2），因此可藉以抑制癌細胞蔓延或治療腫瘤。相對於在藥物醫學上的研究，生物鹼在其他化學領域上的應用顯然較為不足。有鑑於此，本論文於是就生物鹼在陰離子辨識上進行探討。 實驗顯示：Palmatine與Berberine在水溶液中無法與陰離子進行交互作用，但於非水溶液中則可與氟離子進行交互作用。由於Palmatine與Berberine不會與其他鹵素離子產生類似反應，Palmatine與Berberine在氟離子辨識上極具專一性與應用潛力。根據紫外光-可見光吸收光譜、螢光光譜與電化學分析，Palmatine與Berberine在DMSO中可與一個氟離子結合，結合常數約為1105。X-射線吸收光譜分析也証實此一結論，發現在Palmatine與Berberine分子中的氮原子，其K-edge會隨氟離子濃度增加而呈現系統性變化。此一結果顯示Palmatine與Berberine分子中的氮原子應是與氟離子進行交互作用的反應中心。有鑑於此交互作用，本論文也探討以Palmatine加速氟離子傳輸之潛力。Polycyclic aromatic alkaloids, such as palmatine and berberine, are potential DNA-targeting drugs that can intercalate into the AT-minor groove of DNA. Because the associated adducts are highly fluorescent and can convert 3O2 into 1O2 under UV irradiation, they are potential inhibitors of cancer cells. Despite the fruitful study in this aspect, research on other aspects, such as anion recognition, seems to be relatively rare. According to our study, palmatine and berberine interact weakly with fluoride, chloride, bromide, iodide, nitrate, perchlorate and sulfate in aqueous media, but they interact strongly with fluoride ion in aprotic environments, reflected in its UV-Vis absorption spectra, emission spectra and electrochemical behavior. The quaternary nitrogen atom in palmatine is responsible for the interaction with F- ions, evidenced by the N K-edge measurements and the characterizations with the analogues of palmatine, berberine and canadine. Because of such a specific interaction, palmatine and berberine show promise in fluoride transport.