Herbal formulations are complex natural mixtures. Researchers usually tend to focus more on analysis of nonvolatile components but pay less attention to volatile compounds. In this study, an analytical strategy combining two approaches was established for comprehensive analysis of herbal formulations.
Guizhi Fuling capsule (GFC), a
drug approved by the FDA to enter phase II clinical trial for treatment of primary
dysmenorrhea, was taken as a case for analysis. Gas chromatography-mass spectrometry (GC-MS) with automated mass spectral deconvolution and identification system (AMDIS) led to rapid identification of 48 volatile components including four
acetophenones, three
fatty acid esters, 13 phenylpropanoids and 19
sesquiterpenes. Most of them were found from Guizhi. The
volatile oils of Guizhi have been proved to exhibit many pharmacological activities. This is helpful in understanding the pharmacological mechanism of GFC. Furthermore, AMDIS turned out to be efficient and reliable for analysis of complex herbal formulations. Rapid-resolution liquid chromatography (RRLC) coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (ESI-Q-TOF MS/MS) allowed the identification of 70 nonvolatile components including six
acetophenones, 12 galloyl glucoses, 31
monoterpene glycosides, three
phenols and 12
triterpene acids. Fragmentation behaviors of assigned components, especially
triterpene acids, which are hard to identify by low-resolution MS, were first investigated by TOF MS/MS. Characteristic
ions and typical loss of assigned
triterpene acids were summarized. Combinatorial use of GC-MS-AMDIS and RRLC-ESI-Q-TOF MS/MS could be of great help in global qualitative analysis of GFC, as well as other herbal products.