Department of Basic Medical Sciences, Royal College of Surgeons in Ireland, Medical University of Bahrain, P.O. Box 15503, Adliya, Bahrain.
Department of Basic Medical Sciences, Royal College of Surgeons in Ireland, Medical University of Bahrain, P.O. Box 15503, Adliya, Bahrain.
Spectrochim Acta A Mol Biomol Spectrosc. 2017 Aug 5;183:439-450. doi: 10.1016/j.saa.2017.04.027. Epub 2017 Apr 21.
Curcumin is a yellow phenolic compound with a wide range of reported biological effects. However, two main obstacles hinder the use of curcumin therapeutically, namely its poor bioavailability and photostability. We have synthesized two curcumin complexes, the first a boron curcumin complex (B-Cur) and the second an iron (Fe-Cur) complex of curcumin. Both derivatives showed high fluorescence efficiency (quantum yield) and greater photostability in solution. The improved photostability could be attributed to the coordination structures and the removal of β-diketone group from curcumin. The fluorescence and ultra violet/visible absorption spectra of curcumin, B-Cur and Fe-Cur all have a similar spectral pattern when dissolved in the same organic solvent. However, a shift towards a lower wavelength was observed when moving from polar to non-polar solvents, possibly due to differences in solvent polarity. A plot of Stokes' shift vs the orientation polarity parameter (Δf) or vs the solvent polarity parameter (E 30) showed an improved correlation between the solvent polarity parameter than with the orientation polarity parameter and indicating that the red shift observed could be due to hydrogen-bonding between the solvent molecules. A similar association was obtained when Stokes' shift was replaced by maximum synchronous fluorescence. Both B-Cur and Fe-Cur had larger quantum yields than curcumin, suggesting they may be good candidates for medical imaging and in vitro studies.
姜黄素是一种黄色酚类化合物，具有广泛的报道生物效应。然而，有两个主要障碍阻碍了姜黄素的治疗应用，即其生物利用度差和光稳定性差。我们合成了两种姜黄素配合物，第一种是硼姜黄素配合物（B-Cur），第二种是姜黄素的铁（Fe-Cur）配合物。两种衍生物在溶液中都表现出高荧光效率（量子产率）和更高的光稳定性。光稳定性的提高可归因于配位结构和从姜黄素中去除β-二酮基团。当溶解在相同的有机溶剂中时，姜黄素、B-Cur 和 Fe-Cur 的荧光和紫外/可见吸收光谱具有相似的光谱模式。然而，当从极性溶剂移动到非极性溶剂时，观察到向较低波长的位移，这可能是由于溶剂极性的差异。Stokes 位移与取向极性参数（Δf）或与溶剂极性参数（E30）的关系图表明，与取向极性参数相比，溶剂极性参数之间的相关性更好，表明观察到的红移可能是由于溶剂分子之间的氢键。当 Stokes 位移被最大同步荧光取代时，也获得了类似的关联。B-Cur 和 Fe-Cur 的量子产率均大于姜黄素，表明它们可能是医学成像和体外研究的良好候选物。
