Determination of curcumin in urine by capillary electrophoresis

The major component of the plant curcuma longa (a widely cultivated tropical plant in Asia and Central America) is curcumin. Curcumin has been reported to have very strong anti-inflammatory, anti-carcinogenic, anti-oxidant, antiallergic, anti-bacterial, and (anti-tumor) activities. Little is known about the absorption, distribution, and metabolism of curcumin in human beings. The first step in in vivo physiological and pharmacokinetic studies is to develop a method to measure curcumin in body fluid. A rapid capillary electrophoretic (CE) method with diode array detection was established for the determination of curcumin in human urine. It could be rapidly determined within 2.5 min. The optimized experimental conditions were as follows: 15 mmol/L Na_2B_4O_7 as buffer, applied voltage 20 kV, temperature 25 ℃ and detection wavelength 262 nm. The method has been validated and shows good performance with respect to selectivity, reproducibility and limit of detection. Curcumin had good linearity in the range of 10-300 mg/L, and the recoveries of curcumin added in urine were more than 96.3% with relative standard deviations (RSDs) less than 2.3%. The method is sensitive, fast and accurate and can be used to determine curcumin in urine.