Improving Solubility of Curcumin in Aqueous System by the Self- Assembly of Hyperbranched Poly(amide-ester) and Curcumin

In order to improve the water-solubility of curcumin, the complex between curcumin and hyperbranched poly(amide-ester) was formed by dispering the solid curcumin in hyperbranched poly(amide-ester) aqueous solution. The interaction process was characterized by UV-vis absorption spectroscopy, Fluorescence quenching method, Fourier transformation-infrared spectroscopy, thermogravimetric analysis. Fluorescence quenching ananlysis reveal that the fluorescence quenching of curcumin is due to the formation of ground state complex between curcumin and hyperbranched poly(amide-ester) and the binding constant was 3.98×10 5 L·mol -1 . The other analysis also can prove the formation of complex between curcumin and HBPAE. The solubility of curcumin in aqueous solution was greatly increased more than 1000-fold at the presence of hyperbranched poly(amide-ester). INTRODUCTION: Curcumin (CUR) (Scheme 1) containing keto-enol-enolate equilibrium is a kind of pigment that isolated from the rhizomes of turmeric. It could be commonly utilized as food dye and spice in curries. 1, 2, 3 In recent years, many researchers discovered that CUR and its derivatives exhibited some amazing properties such as antioxidant, anti-inflammation, anti-microbial, anticancer and anti-mutagenic with low intrinsic toxicity. 4,5 However, its poor water-solubility restricted its practical application in biology to a great degree. Thus, it is urgent to improving the water-solubility of CUR. Recently, scholars have made great efforts to develop new methods to increase the water-solubility of CUR, such as nanoparticles, 6 nanogels, 7, 8 conjugates 9, 10 and