title: 6,8-Di-C-methyl-flavonoids with neuroprotective activities from Rhododendron fortunei.
abstract: Six 6,8-di-C-methyl-flavonoids, (2R,3R)-6,8-di-C-methyl-5,7,4'-trihydroxyflavanonol 7-O-β-d-gluco-pyranoside (1), (2R,3R)-6,8-di-C-methyl-5,7,4'-trihydroxyflavanonol 7-O-β-d-xylopyranosyl(1→6)-β-d-glucopyranoside (2), 6,8-di-C-methylkaempferol 7-O-β-d-glucopyranoside (3), (2R)-farrerol (4a), (2R/2S)-farrerol 7-O-β-d-glucopyranoside (5), and (2R/2S)-farrerol 7-O-β-d-xylopyranosyl(1→6)-β-d-glucopyranoside (6), and four known analogues, farrerol (4b), (2R,3R)-6,8-di-C-methyldihydrokae-mpferol (7), 6,8-di-C-methylkaempferol 7-O-β-d-glucopyranoside (8), and 6,8-di-C-methylkaempferol (9), were isolated from the twigs and leaves of Rhododendron fortunei. The structures of compounds 1-9 were determined by spectroscopic analyses (HRESIMS, 1D and 2D NMR, and CD) and chemical methods. Compounds 1-9 were evaluated for their neuroprotective effects on the human neuroblastoma SH-SY5Y cells apoptosis induced by hydrogen peroxide (H2O2) and amyloid β peptide (Aβ), respectively. Compounds 1-3 and 5-9 exhibited significant neuroprotective effects against H2O2-induced SH-SY5Y cell apoptosis, and compound 8 exhibited the strongest activity with a improvement of cell viability by about 30% at the concentration of 10μM. Compounds 1-9 showed significant neuroprotective effects against Aβ-induced SH-SY5Y cell apoptosis.
authors.affiliation: Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China; Department of Pharmacy, Central Hospital of Wuhan, Wuhan 430014, People's Republic of China.
authors.forename: Yongji
authors.initials: Y
authors.lastname: Lai
authors.affiliation: Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China.
authors.forename: Hong
authors.initials: H
authors.lastname: Zeng
authors.affiliation: Institute of Chinese Herbal Medicines, Hubei Academy of Agricultural Sciences, Enshi 445500, People's Republic of China.
authors.forename: Meijun
authors.initials: M
authors.lastname: He
authors.affiliation: Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China.
authors.forename: Huiqin
authors.initials: H
authors.lastname: Qian
authors.affiliation: Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China.
authors.forename: Zhaodi
authors.initials: Z
authors.lastname: Wu
authors.affiliation: Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China.
authors.forename: Zengwei
authors.initials: Z
authors.lastname: Luo
authors.affiliation: Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China.
authors.forename: Yongbo
authors.initials: Y
authors.lastname: Xue
authors.affiliation: Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China. Electronic address: gyap@hust.edu.cn.
authors.forename: Guangmin
authors.initials: G
authors.lastname: Yao
authors.affiliation: Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China. Electronic address: zhangyh@mails.tjmu.edu.cn.
authors.forename: Yonghui
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D017209:Apoptosis; D045744:Cell Line, Tumor / Q000187:drug effects; D005419:Flavonoids / Q000737:chemistry* / Q000302:isolation & purification; D006801:Humans; D015394:Molecular Structure; D009447:Neuroblastoma / Q000473:pathology; D018696:Neuroprotective Agents / Q000737:chemistry* / Q000302:isolation & purification; D010936:Plant Extracts / Q000737:chemistry; D018515:Plant Leaves / Q000737:chemistry; D029793:Rhododendron / Q000737:chemistry*
chemical_list: D005419:Flavonoids; D018696:Neuroprotective Agents; D010936:Plant Extracts
keywords: C-methyl-flavonoids; Ericaceae; Neuroprotective effects; Rhododendron fortunei; Structure elucidation