title: Baeckeins F-I, four novel C-methylated biflavonoids from the roots of Baeckea frutescens and their anti-inflammatory activities.
abstract: Baeckea frutescens is an aromatic shrub used in South China as an ornamental and as a spice. Four unusual C-methylated biflavonoids named baeckeins F-I (1-4) were isolated from the roots of B. frutescens. The baeckeins F-I possessed a unique carbon skeleton, a flavonol conjugated with a coumaronochromone molecule via the unusual linkages of C-2-C-8 and C-3-O-C-7. Their structures were elucidated by analysis of the 1D ((1)H/(13)C) and 2D NMR (HSQC/HMBC/NOESY) and HR-ESI-MS spectroscopic data, and the absolute stereochemistry for chiral carbons of C-2 and C-3 was established by CD spectrometry combined with quantum chemical calculations. Baeckeins F-I (1-4) were also evaluated for their anti-inflammatory activities by detecting the NO production of LPS-induced RAW264.7 murine macrophage cell line; baeckein I (4) with the β-d-glucose unit and configuration of (2R,3R) exhibited the highest NO inhibitory activity (IC50=15.2 μM), which was similar to that of the positive control indomethacin.
authors.affiliation: Department of Pharmacognosy, College of Pharmacy, Zhengzhou University, No. 100 of Science Road, Zhengzhou 450001, PR China; State Key Laboratory of Natural Medicines, China Pharmaceutical University, No. 24 Tongjia Lane, Nanjing 210009, PR China. Electronic address: jiabeixi_2003_123@163.com.
authors.forename: Bei-Xi
authors.initials: BX
authors.lastname: Jia
authors.affiliation: Department of Pharmacognosy, College of Pharmacy, Zhengzhou University, No. 100 of Science Road, Zhengzhou 450001, PR China.
authors.forename: Xian-Lei
authors.initials: XL
authors.lastname: Zeng
authors.affiliation: Henan Zhongshuai Pharmaceutical Science and Technology Development Co., Ltd, Zhengzhou 450001, PR China.
authors.forename: Feng-Xiao
authors.initials: FX
authors.lastname: Ren
authors.affiliation: Department of Pharmacognosy, College of Pharmacy, Zhengzhou University, No. 100 of Science Road, Zhengzhou 450001, PR China.
authors.forename: Lu
authors.initials: L
authors.lastname: Jia
authors.affiliation: State Key Laboratory of Natural Medicines, China Pharmaceutical University, No. 24 Tongjia Lane, Nanjing 210009, PR China.
authors.forename: Xiao-Qing
authors.initials: XQ
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Natural Medicines, China Pharmaceutical University, No. 24 Tongjia Lane, Nanjing 210009, PR China.
authors.forename: Jie
authors.initials: J
authors.lastname: Yang
authors.affiliation: Department of Pharmacognosy, College of Pharmacy, Zhengzhou University, No. 100 of Science Road, Zhengzhou 450001, PR China. Electronic address: liuhm@zzu.edu.cn.
authors.forename: Hong-Min
authors.initials: HM
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Natural Medicines, China Pharmaceutical University, No. 24 Tongjia Lane, Nanjing 210009, PR China. Electronic address: qwang49@163.com.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Wang
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D044946:Biflavonoids / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D002460:Cell Line; D004365:Drugs, Chinese Herbal / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D008264:Macrophages / Q000187:drug effects / Q000276:immunology; D051379:Mice; D015394:Molecular Structure; D027822:Myrtaceae / Q000737:chemistry*; D018517:Plant Roots / Q000737:chemistry*
chemical_list: D000893:Anti-Inflammatory Agents; D044946:Biflavonoids; D004365:Drugs, Chinese Herbal
keywords: Absolute configuration; Anti-inflammatory activity; Baeckea frutescens; Baeckeins F–I; C-methylated biflavonoid