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A method that couples rapid, sensitive, reproducible and accurate ultra-performance LC (UPLC) with quadrupole-TOF-MS was established for the first simultaneous qualitative and quantitative analysis of phenolic compounds in Artemisia minor. Box-Behnken designs (BBDs) were applied as an effective tool to optimise major parameters that influence the resolution of UPLC, including three gradient steps and column temperature. Under optimal UPLC conditions, a total of 23 phenolic compounds in the crude methanol extracts of A. minor were well separated on a Waters Acquity UPLC BEH C(18) column (100×2.1 mm, 1.7 μm particle size) within 16.5 min, and the compounds were unequivocally or tentatively identified via comparisons with authentic standards and literature. In this study, a total of six major phenolic compounds were quantified in A. minor and the method was validated to be sensitive, precise and accurate within the LOD from 1.24 to 5.27 μg/mL, and the overall intra- and inter-day variations in detection were less than 3.76%. The recovery of the method ranged from 97.9 to 103.8% with RSDs that were less than 5.8%. These results demonstrate that this approach has the potential for quality control of A. minor and other Tibetan herbal medicines.

Two cyclolanostane-type saponins, astragalosides I and II, were first identified by TLC-MS/MS in the ethyl acetate extract of the roots of Astragalus membranaceus Bge var. mongholicus (Bge.) Hsiao without chemical reference substances. They were then isolated by high-speed counter-current chromatography with a two-step two-phase solvent system of ethyl acetate-2-propanol-water (5:1:5, 50:1:50, v/v/v). The quantities of astragalosides I and II isolated from 1 g of the crude extract were 30.2 mg and 16.5 mg, respectively. Their purities were found to be over 95% by HPLC-ELSD analysis. Their chemical structures were confirmed by 1H and 13C nuclear magnetic resonance analysis.