Adsorption and desorption of lignans, flavonoids, phenolic acids by macroporous adsorbent resins during extraction of Astragali radix and stir-fried Arctii Fructus

Abstract

Astragali radix and Arctii Fructus are extensively utilized in traditional Chinese medicine and have demonstrated efficacy in mitigating renal damage associated with early diabetic nephropathy. To facilitate the comprehensive extraction and application, this study aimed to devise a streamlined and efficacious approach for the preparative purification of lignans, flavonoids, and phenolic acids from Astragali Radix, as well as stir-fried Arctii Fructus, using macroporous resin column chromatography. Initially, the adsorption and desorption characteristics of these compounds on six distinct macroporous resins were investigated, leading to the selection of XDA-8 resin. Subsequently, a combination of column chromatography, single factor testing, and orthogonal experimental design was employed to optimize the technological parameters for the purification process.The desorption rates achieved were notable: lignans at 80.61%, flavonoids at 73.79%, and phenolic acids at 58.96%. In addition, a comparative analysis was conducted on the extracts before and after purification using high-performance liquid chromatography with photodiode-array detection (HPLC-PAD). The results demonstrated that the purified product contained higher amounts of all seven constituents than prior to purification. Therefore, macroporous resin column chromatography utilizing XDA-8 resin, as established in this study, emerges as a promising method for the industrial-scale purification of Astragali Radix and stir-fried Arctii Fructus.