Spectrometric Study on the Interaction of Dodecyltrimethylammonium Bromide with Curcumin

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• 作者：Dan Ke ; Xiaoyong Wang ; Qianqian Yang ; Yumeng Niu ; Shaohu Chai ; Zhiyun Chen ; Xueqin An ; Weiguo Shen
• 刊名：Langmuir
• 出版年：2011
• 出版时间：December 6, 2011
• 年：2011
• 卷：27
• 期：23
• 页码：14112-14117
• 全文大小：790K
• 年卷期：v.27,no.23(December 6, 2011)
• ISSN：1520-5827

文摘

The interaction between dodecyltrimethylammonium bromide (DTAB) and curcumin has been studied in pH 5.0 sodium phosphate buffer using absorption and fluorescence measurements. With increasing DTAB concentration (C_DTAB) from 0 to 20 mM, the absorption peak of curcumin at 430 nm, corresponding to the conjugated structure of curcumin, first weakens gradually into a shoulder but increases back into one peak with much higher absorption intensity. On the contrary, as C_DTAB increases, the initial small absorption shoulder of curcumin at 355 nm, corresponding to the feruloyl unit of curcumin, first increases gradually into a clear peak but decreases back into one shoulder until almost disappeared finally. By remaining at nearly the same wavelength, the fluorescence of curcumin first decreases at C_DTAB lower than 5 mM and then increases gradually up to C_DTAB = 10 mM, which is followed by sharp increases of fluorescence intensity with marked blue-shifts at higher C_DTAB. The values of anisotropy and microviscosity of curcumin obtained from the fluorescence polarization technique also showed pronounced changes at different surfactant concentrations. The interaction mechanisms of DTAB with curcumin have been presented at low, intermediate, and high surfactant concentrations, which is relating to interaction forces, surfactant aggregations, as well as structural alterations of curcumin.