Comprehensive evaluation of chemical constituents and antioxidant activity between crude and processed Polygalae...

Polygalae radix (PR) is a famous herbal medicine obtained by drying the root of Polygala tenuifolia Willd., one of the traditional Chinese medicines (TCM) that can be used for healthy food. There are three main processed methods of PR, including removing the xylem of roots (Polygalae Cortex, PC), frying PC with licorice (LP), and frying PC with honey (HP). While processing is believed to enhance efficacy and reduce toxicity, it is crucial to understand the differences in chemical composition and biological activities between crude and processed PR. This study used ultra-performance liquid chromatography with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS/MS) combined with multivariate statistical analysis to analyze the chemical profiles and differences between the crude and processed products. Total polyphenol contents (TPC), total flavonoid contents (TFC), total saponin contents (TSC) and antioxidant activity of the processed and crude PR were also investigated. A total of 131 chemical compounds, including 42 saponins, 44 oligosaccharide esters, 25 xanthones, 2 organic acids, 3 Carbohydrates, and 15 components detected in auxiliary materials, were detected in all samples. Notably, PC exhibited significant changes among the three processed products, with the content of 62 compounds being higher. Processing of licorice (LP) and honey (HP) decreased the content of several compounds due to temperature and moisture influences. Comprehensive comparison of the antioxidant capacity of crude and processed PR showed that the antioxidant capacity of PC was higher than that of PR, HP, and LP. Our results can provide a scientific basis for further developing and applying P. tenuifolia resources.