Integrating UPLC-QTOF-MS/MS and UPLC-DAD to evaluate the influence of sulfur-fumigated Paeoniae Radix Alba on the overall quality of three Si-Wu-Tang formulations.

Introduction: Sulfur-fumigation of Paeoniae Radix Alba (PRA) could induce the chemical transformation of its bioactive component paeoniflorin into a sulfur-containing derivative paeoniflorin sulfite, and thus alter the quality, bioactivities, pharmacokinetics, and toxicities of PRA. However, how sulfur-fumigated PRA (S-PRA) affects the quality of PRA-containing complex preparations has not been intensively evaluated.

Objectives: We intend to evaluate the influence of S-PRA on the overall quality of three kinds of Si-Wu-Tang (SWT) formulations, i.e., decoction (SWT-D), granule (SWT-G), and mixture (SWT-M).

Material And Methods: An UPLC-DAD multi-components quantification method was used to compare the transfer rates of paeoniflorin sulfite and other 10 bioactive components between S-PRA-containing and NS-PRA-containing SWT formulations. An UPLC-QTOF-MS/MS-based target metabolomics approach was applied to explore the differential sulfur-containing derivatives in S-PRA-containing SWT formulations.

Results: The transfer rates of paeoniflorin sulfite in three S-PRA-containing SWT formulations were all higher than 100%. Moreover, S-PRA also increased the transfer rate of 5-hydroxymethylfurfural, 1,2,3,4,6-O-pentagalloylglucose, whereas decreased that of paeoniflorin, albiflorin, and ferulic acid in three SWT formulations. Six pinane monoterpene glucoside sulfites originally identified in S-PRA, were also detectable in three S-PRA-containing SWT formulations. In addition, seven phenolic acid sulfites including (3Z)-6-sulfite-ligustilide, (3E)-6-sulfite-ligustilide, 6,8-disulfite-ligustilide, ferulic acid sulfite, neochlorogenic acid sulfite, chlorogenic acid sulfite, and angelicide sulfite (or isomer) were newly identified in these three S-PRA-containing formulations.

Conclusion: S-PRA could differentially affect the transfer rate of paeoniflorin sulfite and other bioactive components during the preparation of three SWT formulations and subsequently the overall quality thereof.