Manolova Yana, Deneva Vera, Antonov Liudmil, Drakalska Elena, Momekova Denitsa, Lambov Nikolay
Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bldg. 9, 1113 Sofia, Bulgaria.
Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bldg. 9, 1113 Sofia, Bulgaria.
Spectrochim Acta A Mol Biomol Spectrosc. 2014 Nov 11;132:815-20. doi: 10.1016/j.saa.2014.05.096. Epub 2014 Jun 11.
The tautomerism of curcumin has been investigated in ethanol/water binary mixtures by using UV-Vis spectroscopy and advanced quantum-chemical calculations. The spectral changes were processed by using advanced chemometric procedure, based on resolution of overlapping bands technique. As a result, molar fractions of the tautomers and their individual spectra have been estimated. It has been shown that in ethanol the enol-keto tautomer only is presented. The addition of water leads to appearance of a new spectral band, which was assigned to the diketo tautomeric form. The results show that in 90% water/10% ethanol the diketo form is dominating. The observed shift in the equilibrium is explained by the quantum chemical calculations, which show that water molecules stabilize diketo tautomer through formation of stable complexes. To our best knowledge we report for the first time quantitative data for the tautomerism of curcumin and the effect of the water.
通过紫外可见光谱和先进的量子化学计算，研究了姜黄素在乙醇/水二元混合物中的互变异构现象。基于重叠谱带解析技术，采用先进的化学计量学方法对光谱变化进行处理。结果，估算了互变异构体的摩尔分数及其各自的光谱。结果表明，在乙醇中仅存在烯醇-酮互变异构体。加入水会导致出现一个新的光谱带，该光谱带被归属于二酮互变异构形式。结果表明，在90%水/10%乙醇体系中，二酮形式占主导。量子化学计算解释了观察到的平衡移动，该计算表明水分子通过形成稳定的络合物来稳定二酮互变异构体。据我们所知，我们首次报道了姜黄素互变异构现象的定量数据以及水的影响。
