紫外光是造成白內障重要原因之一，而真正影響水晶體蛋白的是紫外光波長範圍是 (UVA)，水晶體暴露在UVA環境下，會進行光氧化反應，產生活性氧物質，使胺基酸被氧化，破壞蛋白質結構與活性。
薑黃素與去甲基薑黃素則具有捕捉與抑制自由基能力，將其添加入α水晶體蛋白中，進行照光實驗，並利用圓二色光譜，探討蛋白質二級結構變化;利用Trp螢光光譜及ANS螢光光譜，了解蛋白質Trp環境變化與表面疏水性暴露改變;利用DTT誘導胰島素集結來測試伴護活性能力。
利用圓二色光譜探討照光影響下隨時間變化關係，在波長222nm，時間對橢圓率作圖可以得到一條型曲線，其中反摺點位置在第七小時，此時的結構穩定度最差，變化最明顯。在DPPH自由基抓取能力測試中，去甲基薑黃素比薑黃素抗氧化能力強約1.8倍，利用紫外光/可見光譜儀測試UVA波長範圍的吸收值，甲氧基薑黃素比薑黃素強約兩倍，探討以上兩個實驗結果與抑制紫外光傷害水晶體蛋白相關性，做蛋白質性質與結構出現明顯的變化:由圓二色光譜結結果來看，添加去甲基薑黃素的α水晶體蛋白二級結構變化最小，保護能力勝過薑黃素，且添加的化合物濃度高，效果較佳；Trp螢光與ANS螢光光譜結果都顯示去甲基薑黃素的添加效果較佳，使α水晶體蛋白疏水性變化趨緩(增加或減少)；伴護活性測試結果則呼應ANS螢光測試的結果，隨著照光時間增加，表面疏水性下降，伴護活性也會下降，相較於一般α水晶體蛋白照光實驗，添加去甲基薑黃素實驗組則是隨著時間增加伴護活性下降變化更小，優於薑黃素實驗組。
實驗結果顯示:在照光實驗中，紫外光所誘導的活性氧物質會影響蛋白質，因此添加化合物具有(1)強自由基抓取能力、(2)紫外光UVA波長範圍吸收能力強特質，對於保護α水晶體蛋白受到紫外光影響有正相關性。

UVA(320nm-380nm) is a foreign stress to cause the damage of lens through photo-oxidation to produce active species, which in turn resulting in the modification of the lens crystalline residues as to lose its proper structure and chaperoning activity of the alpha-crystallin, and finally leads to the formation of lens cataract.
Curcumin has been known as an antioxidant to scavenge the free radicals. And we have found that demethylated curcumin showed better bioactivity in protecting lens from selenite damage. Therefore, in this study, we focus on the effects of these two compound on the prevention of lens crystallins from UV damage by employing Circular Dichroism (CD)to investigate the UV induced structural change of lens crystallins, also to measure the ANS and tryptophan fluorescence to investigate the hydrophobic exposure, and finally bio-assaying the chaperone activity of the UV irradiated alpha-cystallin with or without the presence of curcumin and demethylated curcumin.
The stability of rat lens alpha-crystallin determined by CD measured at 222 nm showed the stability reflection of irradiation time (TM) fitted into the sigmoidal equation was 7 hours. It was found that the UVA absorbance for demethylated curcumin was two-fold of curcumin and the ability to scavenge free radical was 80% higher for demethylated curcumin when compared to curcumin. With the increase of irradiation time, the surface hydrophobicity of alpha-crystallin decreased, which was consistent with the chaperone-like activity of alpha-crystallin toward the DTT-induced insulin B aggregation. And it was also found that the demethylated curcumin showed better chaperone-like activity.

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