Comparative identification of phytoecdysteroids in Achyranthes bidentata Blume and its three analogous species and application in differentiation between processing products from different species.

The differentiation of raw herbal products from similar species have been achieved by plant metabolomics. However, the distinguishment on various processed products with improved activities and wide clinical utilization from similar species is still tricky due to obscure composition variations during processing. In this study, a comprehensive analysis of phytoecdysteroids in Achyranthes bidentata Blume (AB) and its three analogous species, which were all called Niuxi in Chinese, was conducted on UPLC-HRMS by integrating dynamic exclusion acquisition with data post-processing of targeted multilateral mass defect filter. Two most frequently used species, AB and Cyathula officinalis Kuan (CO) were systematically compared with plant metabolomics methods. And the differential components from the raw materials were evaluated on the ability of distinguishing processed products. The substitution of hydroxyl groups on C-21, C-20, C-22 and C-25 were determined by characteristic mass differences, leading to systematical characterization of 281 phytoecdysteroids. In plant metabolomics studies of raw AB and CO, 16 potential markers were filtered by VIP value > 1, and displayed satisfactory differentiation on the processed AB and CO. The results facilitated the quality control of the four species, especially the processed products of AB and CO, also provided a reference method for the quality control of other processed products.