Jeon, Je-Seung Kim, Hak Gi Um, Byung Hun Kim, Chul Young 2024-01-20T17:03:56Z 2024-01-20T17:03:56Z 2021-09-02 2011-05 0149-6395 https://pubs.kist.re.kr/handle/201004/130416 High-performance liquid chromatography coupled to an on-line ABTS+-based assay (on-line HPLC-ABTS+) system was used to determine the principle antioxidants in azalea flowers. Three flavonoids, myricetin, quercetin, and kaempferol, recovered in ethyl acetate extracts of azalea flowers were determined to have antioxidant activities. These three flavonoids were isolated and purified by successive centrifugal partition chromatography (CPC) using two different biphasic solvent systems, consisting of n-hexane-ethyl acetate-methanol-water (3:5:3:5 or 4:5:4:5, v/v). A total of 46.2mg of myricetin, 28.9mg of quercetin, and 10.6mg of kaempferol with purities of 97.0%, 95.4%, and 93.9%, respectively, were purified from 500mg of ethyl acetate soluble material from azalea flowers. The structures were identified by their retention time, UV spectra, and ESI-MS in the positive ion mode and were confirmed by NMR experiments. English TAYLOR & FRANCIS INC SEPARATION Rapid Detection of Antioxidant Flavonoids in Azalea (Rhododendron mucronulatum) Flowers using On-line HPLC-ABTS plus System and Preparative Isolation of Three Flavonoids by Centrifugal Partition Chromatography Article 10.1080/01496395.2010.520296 1 SEPARATION SCIENCE AND TECHNOLOGY, v.46, no.3, pp.518 - 524 SEPARATION SCIENCE AND TECHNOLOGY 46 3 518 524 scie scopus 000288274200018 2-s2.0-79952428508 Chemistry, Multidisciplinary Engineering, Chemical Chemistry Engineering Article SEPARATION antioxidant azalea flowers centrifugal partition chromatography flavonols on-line HPLC-ABTS plus system