title: Antioxidant activities and phytochemicals of leaf extracts from 10 native rhododendron species in taiwan.
abstract: Rhododendron, one of the most famous ornamental plants in the world, is traditionally a medicinal plant. However, the potential bioactivities of native Rhododendron in Taiwan have not been completely studied. In this study, the results revealed that Rhododendron pseudochrysanthum exhibited the best antioxidant activities among 10 native Rhododendron species in Taiwan. Furthermore, based on a bioactivity-guided isolation principle, nine specific phytochemicals were isolated and identified as (2R,3S)-catechin (1), (2R,3R)-epicatechin (1'), (2R,3R)-dihydromyricetin 3-O- β -l-arabinopyranoside (2), (2S,3S)-taxifolin 3-O- β -l-arabinopyranoside (2'), (2R,3R)-taxifolin 3-O- β -l-arabinopyranoside (3), myricetin 3-O- β -d-glucopyranoside (3'), rutin (4), hyperoside (5), and quercitrin (6). Of these compounds, 2 and 3 were found to be major bioactive compounds, and their concentrations in the n-butanol (BuOH) fraction were determined to be 52.0 and 67.3 mg per gram, respectively. These results demonstrated that methanolic extracts of Rhododendron pseudochrysanthum leaves have excellent antioxidant activities and great potential as a source for natural health products.
authors.affiliation: Department of Forestry, National Chung Hsing University, Taichung 402, Taiwan.
authors.forename: Chi-Yang
authors.initials: CY
authors.lastname: Lin
authors.affiliation: Department of Forestry and Natural Resources, National Chiayi University, Chiayi 600, Taiwan.
authors.forename: Lei-Chen
authors.initials: LC
authors.lastname: Lin
authors.affiliation: Department of Forestry, National Chung Hsing University, Taichung 402, Taiwan.
authors.forename: Shang-Tse
authors.initials: ST
authors.lastname: Ho
authors.affiliation: Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan.
authors.forename: Yu-Tang
authors.initials: YT
authors.lastname: Tung
authors.affiliation: Department of Forestry, National Chung Hsing University, Taichung 402, Taiwan.
authors.forename: Yen-Hsueh
authors.initials: YH
authors.lastname: Tseng
authors.affiliation: Department of Forestry, National Chung Hsing University, Taichung 402, Taiwan.
authors.forename: Jyh-Horng
authors.identifier: 0000-0002-1187-1114
authors.initials: JH
authors.lastname: Wu