In Traditional Chinese Medicine (TCM), preparations consist often in a mixture of herbs. Their quality control is challenging because every single herb already contains hundreds of constituents. The TCM selected for this study is used to treat atopic eczema, a common inflammatory skin disorder. Recently, an open-label clinical study showed the efficacy of this TCM oral formula containing ten herbs [1]. Using this TCM as a model, we aimed at designing an innovative strategy for a rational and comprehensive standardization.
The TCM formula and all single herb extracts were analyzed by UHPLC-PDA-ELSD-HRMS. The UHPLC-HRMS metabolite profiling allows the detection of several thousand m/z features. A strategy was elaborated to filter all this information and select key biomarkers. First, peak picking was performed on all single herbs extracts and on the TCM mixture. Alignment of all features in a 2D reconstructed ion map provided an efficient way to correlate the features to each herb of the mixture. Second, ELSD detection was used as a filter for a selection of the most abundant features. Third, these features were dereplicated by combining MS/MS based molecular network and taxonomy [2]. This information was used for a MS targeted isolation of selected markers by MPLC directly on the mixture of the ten herbs.
The approach enabled an in-depth metabolome characterization of the TCM and allowed an efficient isolation of all markers necessary for a comprehensive standardization of the TCM through multiple targeted MRM quantification. This workflow takes into consideration the complexity of the multi-herb preparation and provides an efficient way for their quality control.
Reference:
1. Li S, et al., Forschende Komplementarmedizin 2013; 20 (3):189-96.
2. Allard P-M, et al., Anal Chem, 2016. 88.