Bioactive Flavonoid Glycosides and HPLC and UPLC Quantification of Commercial Astragali Complanati Semen
Division of Chinese Internal Medicine, Center for Traditional Chinese Medicine, Chang Gung Memorial Hospital, Tao-Yuan 333, Taiwan
Division of Chinese Materia Medica Development, National Research Institute of Chinese Medicine, Ministry of Health and Welfare, Taipei 112, Taiwan
Department of Biochemical Science and Technology, National Taiwan University, Taipei 106, Taiwan
Department of Biochemical Science and Technology, National Chiayi University, Chiayi 600, Taiwan
Department of Life Science, Chinese Culture University, Taipei 113, Taiwan
Graduate Institute of Integrated Medicine, China Medical University, Taichung 404, Taiwan
Author to whom correspondence should be addressed.
Molecules 2020, 25(20), 4762; https://doi.org/10.3390/molecules25204762
Received: 15 September 2020 / Revised: 12 October 2020 / Accepted: 14 October 2020 / Published: 16 October 2020
(This article belongs to the Collection Qualitative and Quantitative Analysis of Bioactive Natural Products)
Eleven compounds, including nine known flavonoid glycosides (1–4, 6–8, and 10–11), one isoflavone glycoside (5), and a glansreginic acid (9), were isolated from the 80% ethanol extract of commercial Astragali Complanati Semen (ACS). All chemical structures were determined by spectroscopic analyses, including 1D and 2D NMR. Compounds 2, 4, 5, 6, 9, and 10 were isolated and identified from the title plant for the first time. Biological evaluation revealed that all the isolates showed promising anti-NO production, and 1, 2, 3, and 8 were more potent in antioxidant activity than vitamin E. The major peaks in the UPLC and HPLC profiles identified their chemical structures by comparing their retention time and UV spectra with those of the reference substances. Furthermore, nine of the eleven samples collected from North, Middle, and South regions of Taiwan possessed similar HPLC fingerprints and were identified as Astragali Complanati Semen, whereas the other two samples from southern Taiwan would be the adulterants due to the different fingerprinting patterns. In addition, an HPLC-UV method was employed to determine the content of target compound complanatuside (11) with good linear regression (R2 = 0.9998) for ACS in the Taiwanese market. Of the isolates, flavonol glycosides 1 and 3 were the major peaks in HPLC/UPLC, and showed more potent antioxidant and anti-NO production activities than that of 11, revealing that these compounds can be the available agents for the quality control of ACS.