| 摘要: | 近期研究發現磺丁基醚-β-環糊精（sulfobutylether-β-cyclodextrin, SBE-β-CD）有效抑制及瓦解β類澱粉蛋白，但以眼睛局部給藥，磺丁基醚-β-環糊精（sulfobutylether-β-cyclodextrin, SBE-β-CD）有安全上的疑慮。因此本實驗選擇使用藥典核准之眼用化合物：羥丙基-β-環糊精（2-hydroxypropyl-β-cyclodextrin，HP-β-CD），探討其與β類澱粉蛋白質的交互作用。
評估羥丙基-β-環糊精抑制β類澱粉蛋白單體聚集效果，以HPLC定量分析，莫爾比1:200 (Molar ratio Aβ:HP-β-CD=1:200)、1:100、1:30、1:15、1:7.5，這五組，經過72小時，殘留(未聚集)之β類澱粉蛋白單體與對照組（1:0無羥丙基-β-環糊精）仍有顯著差異。
為了瞭解羥丙基-β-環糊精及β類澱粉蛋白纖維的交互作用，以自體螢光實驗得知，依據Benesi-Hildebrand plot得知締合常數（association constant, Ka）為1.434 + 2.788 mM-1，而一個β類澱粉蛋白纖維與6.9 + 8.6個羥丙基-β-環糊精的結合。以HPLC實驗計算結合率，莫爾比1:100及1:200的結合率，高於組別1:50。
評估羥丙基-β-環糊精瓦解β類澱粉蛋白纖維實驗中，以硫黃素T實驗得知，莫爾比1:200、1:100、1:50皆能顯著改變纖維構型。由FT-IR實驗得知，莫爾比1:200及1:50，這兩組的測試結果皆落在α螺旋之範圍(1640 ~ 1658 cm-1)，故判斷此二組的β類澱粉蛋白纖維，結構有改變。
綜觀上述，羥丙基-β-環糊精對於β類澱粉蛋白構型有顯著作用，且此為安全眼用化合物，故為有潛力之處方。
Recent studies have found that sulfobutylether-β-cyclodextrin (SBE-β-CD) effectively inhibits and disrupts β-amyloid protein, but it contains safety concerns for optical administration. Therefore, Pharmacopoeia approval compound, 2-hydroxypropyl-β-cyclodextrin (HP-β-CD), is chosen to explore its interaction with Amyloid protein.
Evaluate the effect of hydroxypropyl-β-cyclodextrin in inhibiting the aggregation of β-amyloid monomers. In HPLC test, group in molar ratio 1:200 (Molar ratio Aβ:HP-β-CD=1:200), 1:100, 1:30, 1:15, 1:7.5, the residual (unaggregated) β-amyloid monomers still have significant differences with the control group after 72 hours.
In order to understand the interaction between hydroxypropyl-β-cyclodextrin and β-amyloid fiber, it was learned by autofluorescence experiment. According to Benesi-Hildebrand plot, the association constant (Ka) was 1.434 + 2.788 mM-1, and the compound ratio is one β-amyloid fiber and 6.9 + 8.6 hydroxypropyl-β-cyclodextrin. Calculated by HPLC experiments, the binding rates of 1:100 and 1:200 were significantly higher than those of the group 1:50.
Evaluate the breakdown of β-amyloid fiber by hydroxypropyl-β-cyclodextrin. In Thioflavin T test, it showed that the molar ratio of 1:200, 1:100, and 1:50 can significantly change the fiber configuration. According to the FT-IR experiment, both group the molar ratio of 1:200 and 1:50 are within the range of α helix (1640 ~ 1658 cm-1). The structure of protein fibers has changed.
In summary, hydroxypropyl-β-cyclodextrin has a significant effect on amyloid configuration, and this is a safe ophthalmic compound, so hydroxypropyl-β-cyclodextrin is potential condicate. |
