title: Novel phthalide derivatives identified from Ligusticum chuanxiong (Chuanxiong).
abstract: BACKGROUND
  Ligusticum chuanxiong Hort. (Chuanxiong) is a well-known Chinese medicine, and studies on its chemical constituents are important for explaining its mechanism of action and quality control. This study aims to investigate the chemical constituents of the dried rhizome of. L. chuanxiong.
  
  
  METHODS
  The dried rhizome of L. chuanxiong was extracted with 60 % ethanol, and the concentrated extract was isolated by silica gel, octadecyl silane, and Sephadex LH-20 columns, followed by preparative/semipreparative high-performance liquid chromatography (HPLC) to obtain the pure chemical constituents. The structures of the constituents were elucidated by HR-ESI-MS, UV, IR, 1D NMR, and 2D NMR methods. Enantiomeric separation was achieved by a chiral HPLC method. The absolute configuration was determined by the modified Mosher's method.
  
  
  RESULTS
  Six novel phthalide derivatives, (+)/(-)-chuanxiongins A-F (1-6), together with four known phthalides (7-10) were isolated from Chuanxiong. All of the new compounds (1-6) were present as pairs of enantiomers. Enantiomeric separation of 1 was successfully achieved by HPLC on a chiral column. The absolute configuration of (-)-1 was determined by a modified Mosher's method.
  
  
  CONCLUSIONS
  The six novel phthalide derivatives (1-6) isolated from Chuanxiong were phthalide fatty acid esters that were structurally analogous and characterized by fatty acid acylation at 6-OH or 7-OH.
authors.affiliation: Institute of Traditional Chinese Medicine and Natural Products, Jinan University, Guangzhou, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Yang
authors.affiliation: Institute of Traditional Chinese Medicine and Natural Products, Jinan University, Guangzhou, China.
authors.forename: Xiao-Lin
authors.initials: XL
authors.lastname: Feng
authors.affiliation: Institute of Traditional Chinese Medicine and Natural Products, Jinan University, Guangzhou, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yu
authors.affiliation: Institute of Clinical Pharmacology, Guangzhou University of Chinese Medicine, Guangzhou, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Institute of Traditional Chinese Medicine and Natural Products, Jinan University, Guangzhou, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Zou
authors.affiliation: Institute of Traditional Chinese Medicine and Natural Products, Jinan University, Guangzhou, China.
authors.forename: Chuan-Xi
authors.initials: CX
authors.lastname: Wang
authors.affiliation: Institute of Traditional Chinese Medicine and Natural Products, Jinan University, Guangzhou, China.
authors.forename: Zhen-Qiang
authors.initials: ZQ
authors.lastname: Mu
authors.affiliation: Institute of Traditional Chinese Medicine and Natural Products, Jinan University, Guangzhou, China.
authors.forename: Xin-Sheng
authors.initials: XS
authors.lastname: Yao
authors.affiliation: Institute of Traditional Chinese Medicine and Natural Products, Jinan University, Guangzhou, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Gao
keywords: Chuanxiong; Chuanxiongins; Ligusticum chuanxiong; New subtype of phthalides; Phthalide fatty acid esters