Targeted characterization of acylated compounds from Scrophulariae Radix using liquid chromatography coupled with Orbitrap mass spectrometry and diagnostic product ion-based data analysis.

Acylated compounds are often present in herbal medicines. In this study, a diagnostic product ion-based strategy was established to comprehensively characterize acylated compounds in Scrophulariae Radix. After untargeted data acquisition using ultra-high performance liquid chromatography coupled with Orbitrap mass spectrometry, the data were processed by three-stage diagnostic product ions. First, diagnostic product ions corresponding to the acyl groups (cinnamoyl, p-coumaroyl, feruloyl, and caffeoyl) were used to search 90 compounds. Second, these compounds were divided into three categories using diagnostic product ions for phenylethanoid glycosides, iridoid glycosides, and phenylpropanoids, respectively. Last, the linkage position of the acyl group to iridoid glycosides was discriminated via the third-stage diagnostic product ions. As a result, 90 acylated compounds were characterized, and 37 of them were reported from Scrophulariae Radix for the first time.