Determination of marker constituents in radix Glycyrrhizae and radix Notoginseng by near infrared spectroscopy

Abstract

High-performance liquid chromatographic (HPLC) methods were developed for the determination of glycyrrhizin in radix Glycyrrhizae and ginsenosides Rb₁, Rb₂, Rc, Rd, Re, Rf and Rg₁ in radix Notoginseng. These methods were used as reference methods for near-infrared (NIR) spectroscopy. Spectroscopic calibrations were developed for the determination of glycyrrhizin, the total content of ginsenosides and the individual major ginsenosides Rb₁, Rd, Re and Rg₁. Standard errors of cross validation (SECV) were 1.22 mg g^–1 for glycyrrhizin (concentration range 21.3–34.1 mg g^–1) and 0.99 mg g^–1 for the sum of ginsenosides (concentration range 55.3–¶71.1 mg g^–1). The corresponding coefficients of determination (R²) were 0.94 and 0.98, respectively. The SECVs were generally less than a factor of 2.5 of the repeatability standard deviation of the HPLC methods.