Solubility improvement of curcumin with amino acids

Curcumin (CUR) is used as a dietary and food supplement with medicinal properties. It has a wide range of therapeutic activities such as antioxidant, anti-inflammatory, anti-arthritis, anti-tumor, anti-hyperglycemic, anti-malarial, anti-bacterial, and antiviral properties. The low solubility of curcumin in aqueous medium (7.8 mu g mL(-1)) and low bioavailability leads to its lack of use as an oral medicine. In this work, the use of basic amino acids and their biological derivatives to improve the physicochemical properties of curcumin is described. Binary adducts of CUR with tyramine, tryptamine, arginine, asparagine, glutamine, lysine, histidine, and citrulline were characterized by spectroscopic, thermal, X-ray and microscopic techniques. The solubility and dissolution of curcumin in 40% ethanol-water solution exhibited a considerable improvement for these binary products. The use of amino acids as additives to improve the solubility of CUR in medical supplements is described.