A segmental monitoring strategy based on variable wavelength detection for quality control of three Polygonaceae herbs

Radix Polygoni Multiflori, Rhizoma et Radix Polygoni Cuspidati, and Radix et Rhizoma Rhei are the most frequently used traditional Chinese medicines in the family Polygonaceae. The three herbal medicines (HMs) contain similar types of compounds. In Chinese Pharmacopoeia, five high-performance liquid chromatography (HPLC) coupled with ultraviolet (UV) detection methods have been employed for their quality control. The aim of this study was to develop a simple and conventional strategy, segmental monitoring based on variable wavelength detection (VWD), for simultaneous quantification of phenolic acids, flavonoids, stilbenes and anthraquinones in the three chemically analogous HMs. Compared with the commonly used HPLC-diode array detection (DAD), the proposed method afforded desirable performance on linearity, precision and sensitivity. Additionally, a quadrupole time-of-flight mass spectrometry (QTOF-MS) was applied to the structural confirmation of analytes from complex matrices. Based on the chemical profiles and contents of the analyses, 27 samples from three HMs were well classified using the principal component analysis. The results of this study demonstrated the potential and applicability of segmental monitoring strategy based on VWD for comprehensive quality control of HMs.