Quantitative Evaluation of Twelve Major Components of Astragali Radix Sulfur-Fumigated with Different Durations by UPLC-MS

In this study, an improved UPLC-MS method for simultaneously quantifying twelve major components belonging to two chemical types was developed and validated, and was applied to quantitatively compare the quality of Astragali Radix sulfur-fumigated with different durations and the fresh reference sample. The results showed that the contents of triterpenes Astragaloside III and Astragaloside IV decreased moderately, while the flavonoids calycosin, formononetin, and 7,2'-dihydroxy-3',4'-dimethoxyisoflavane decreased significantly, and its corresponding flavonoid glycosides increased accordingly, which indicatied that the happening of chemical transformation of flavonoids and glycosides in the sulfur-fumigated process. These transformations were further confirmed by the the synthesis of flavonoid glycosides under the simulated sulphur-fumigation circumstances. Furthermore, the sulfur-fumigated duration had a proportional relationship with the contents of compounds 7, 11, and 12. All these results suggested that the established method was precise, accurate and sensitive enough for the global quality evaluation of sulfur-fumigated Astragali Radix, and sulfur-fumigation can not only change the proportions of bioactive components, but also cause the chemical transformation in the Astragali Radix.