title: Spectrometric study on the interaction of dodecyltrimethylammonium bromide with curcumin.
abstract: 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.
authors: School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, China.
authors: Dan
authors: D
authors: Ke
authors: Xiaoyong
authors: X
authors: Wang
authors: Qianqian
authors: Q
authors: Yang
authors: Yumeng
authors: Y
authors: Niu
authors: Shaohu
authors: S
authors: Chai
authors: Zhiyun
authors: Z
authors: Chen
authors: Xueqin
authors: X
authors: An
authors: Weiguo
authors: W
authors: Shen
mesh_terms: D003474:Curcumin / Q000737:chemistry*; D004553:Electric Conductivity; D005454:Fluorescence Polarization; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013053:Spectrophotometry
chemical_list: D000644:Quaternary Ammonium Compounds; C022806:dodecyltrimethylammonium; D003474:Curcumin