An on-line analysis method by HPLC-DAD coupled with chemiluminescence (CL) and ESI-Q-TOF-MS/MS was established for simultaneous detection and identification of antioxidants in three original plants of traditional Chinese medicine "She-gan". Two new isoflavonoid glycosides, along with 48 known compounds, including isoflavonoid glycosides and their aglycones, xanthones, flavones and other phenolic compounds, were identified or tentatively identified from the rhizomes of three Iridaceae plants, namely, Belamcanda chinensis, Iris tectorum and Iris dichotoma, which were used as "She-gan" in China. Among those compounds, isoflavone glycosides of iristectorigenin A and its isomers exhibited obviously inhibit CL, which suggested their strong free radical scavenging activity. The chemometric methods dealing with the data gained by chromatographic and antioxidant activity profiles exhibited the "similarities" and "differences" of chemical constituents and antioxidant activities for three studied Iridaceae species. The results indicated that the established method might provide for qualitative and quantitative evaluation of the herbal medicines.
Keywords: Belamcanda chinensis; Free radical scavenging activity; HPLC–DAD–CL; Iris dichotoma; Iris tectorum.
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