Differential Comparison of Chemical Compositions Between Two Wutou Decoctions Based on Ultrahigh–Performance Liquid Chromatography Coupled With Quadrupole Time‐of‐Flight Tandem Mass Spectrometry Combined With Chemometric Analysis

Wutou decoction is an ancient compound preparation composed of five herbal medicines, which has good therapeutic effects on rheumatoid arthritis. There are two classic preparation methods of Wutou decoction using honey and water as decocting excipients, respectively. However, the differences of chemical compositions between these two Wutou decoctions yet remain unclear. Therefore, honey-decocting Wutou decoction was prepared according to the record written in Synopsis of Golden Chamber, and water-decocting Wutou decoction was prepared by the process commonly used in clinics nowadays. Wutou decoction database was also established for the identification of their chemical compositions. Ultrahigh-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry technique combined with chemometric analysis was further established and applied to analyze their chemical compositions. A total of 128 components were identified in honey-decocting Wutou decoction, whereas 126 components in water-decocting Wutou decoction. Isoguanosine and aromadendrin were found to exist only in honey-decocting Wutou decoction, but not in water-decocting Wutou decoction. Principal component analysis results showed that there were obvious differences between honey-decocting Wutou decoction and water-decocting Wutou decoction. Orthogonal partial least squares discriminant analysis further verified these differences, of which 30 potential differential components were found by calculation of their variable importance in the projection values. Different chemical compositions will inevitably affect the toxicity and safety of Wutou decoction, and it is imperative to calibrate its preparation process.