The Comprehensive Profiling of the Chemical Components in the Raw and Processed Roots of by Combining UPLC-Q-TOF-MS Coupled with MS/MS-Based Molecular Networking.

Scrophulariae Radix (SR), the dried root of Hemsl (), has been extensively used as traditional Chinese medicine for thousands of years. However, since the mid-20th century, the traditional processing technology of has been interrupted. Therefore, ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry technology, together with a Global Natural Product Social Molecular Networking (GNPS) method, was applied to comprehensively analyze the characteristic changes and mutual transformation of chemical constituents in the differently processed roots of , as well as to scientifically elucidate the processing mechanism of differently processed SR. As a result, a total of 149 components were identified. Notably, with the help of the GNPS data platform and MS fragment ions, the possible structures of four new compounds (, , , and ) were deduced in differently processed SR samples, in which , , and are iridoid glycosides, and is a phenylpropanoid glycoside. Five cyclopeptides (, , , , and ) derived from leucine (isoleucine) were identified in SR for the first time. The heatmaps analysis results indicated that leucine or isoleucine may be converted to cyclopeptides under the prolonged high-temperature conditions. Moreover, it is found that short-time steaming can effectively prevent the degradation of glycosides by inactivating enzymes. This study provides a new and efficient technical strategy for systematically identifying the chemical components, rapidly discovering the components, and preliminarily clarifying the processing mechanism of , as well as also providing a scientific basis for the improvement of the quality standards and field processing of