Single robust RP-HPLC analytical method for quantification of curcuminoids in commercial turmeric products, Ayurvedic medicines, and nanovesicular systems

Abstract

<p>A single robust reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed and validated as per International Conference on Harmonization guidelines for the accurate quantification of curcuminoids in commercial turmeric products, Ayurvedic medicines, and nanovesicular systems. The proposed chromatographic method was found to be specific, linear (<i>r</i>² ≥ 0.999), precise at intra- and inter-day levels (percentage relative standard deviation <2.0%), accurate (percentage recovery 99.14–102.29%), and robust. The limits of detection and quantification were found to be 7.40 and 24.70 ng mL⁻¹ for curcumin, 9.24 and 30.80 ng mL⁻¹ for demethoxycurcumin, and 6.48 and 21.61 ng mL⁻¹ for bisdemethoxycurcumin, respectively. Among different commercial turmeric products and Ayurvedic medicines tested, the contents of curcumin (3.54 ± 0.06–25.8 ± 0.08 mg g⁻¹), demethoxycurcumin (1.28 ± 0.02–9.97 ± 0.03 mg g⁻¹), and bisdemethoxycurcumin (0.50 ± 0.01–5.97 ± 0.01 mg g⁻¹) varied significantly. The developed method was effectively applied to the determination of encapsulation efficiency of curcuminoids (ranged between 84.33 ± 3.50 and 96.59 ± 2.53%) in the nanovesicular systems. In conclusion, the reported method is suitable for the analysis of curcuminoids in a wide variety of turmeric products and used for the quality control of products that contain curcuminoids.</p