STABILITY OF CURCUMIN IN BUFFER SOLUTIONS AND CHARACTERIZATION OF ITSDEGRADATION PRODUCTS

The degradation kinetics of curcumin under various pH conditions and t he stability of curcumin in physiological matrices were investigated. When curcumin was incubated in 0.1 M phosphate buffer and serum-free m edium, pH 7.2 at 37 degrees C, about 90% decomposed within 30 min. A s eries of pH conditions ranging from 3 to 10 were tested and the result showed that decomposition was pH-dependent and occurred faster at neu tral-basic conditions. It is more stable in cell culture medium contai ning 10% fetal calf serum and in human blood; less than 20% of curcumi n decomposed within 1 h, and after incubation for 8 h, about 50% of cu rcumin is still remained. Trans-6-(4'-hydroxy-3'methoxyphenyl) -2.3-di oxo-5-hexenal was predicted as major degradation product and vanillin, ferulic acid, feruloyl methane were identified as minor degradation p roducts. The amount of vanillin increased with incubation time. (C) 19 97 Elsevier Science B.V.