title: ACE and platelet aggregation inhibitors from Tamarix hohenackeri Bunge (host plant of Herba Cistanches) growing in Xinjiang.
abstract: BACKGROUND
  Tamarix hohenackeri Bunge is a salt cedar that grows widespread in the desert mountains in Xinjiang. T. hohenackeri has not been investigated earlier, although there are many reports of phytochemical work on other Tamarix species.
  
  
  METHODS
  To find out natural angiotensin-converting enzyme (ACE) inhibitor and platelet aggregation inhibitors, the bioactive extract (ethyl acetate [EtOAc] fraction) from the dried aerial parts of T. hohenackeri were investigated. The active fraction was purified by repeated column chromatography, including silica gel, Sephadex LH-20 column, medium-pressure liquid chromatography (MPLC) (polyamide column) and high-performance liquid chromatography (HPLC). The isolated major constituents were tested for their anti-platelet aggregation activity.
  
  
  RESULTS
  Bioassay-directed separation of the EtOAc fraction of the 70% ethanol extract from the air-dried aerial parts of T. hohenackeri led to the isolation of a new triterpenoid lactone (1), together with 13 known compounds (2-14). It was the first time to focus on screening bioactive constituents for this plant. The chemical structures were established on the basis of spectral data (ESI-MS and NMR). The results showed that the flavonoid compounds (7 and 8) and phenolic compounds (9, 10, 11, and 14) were potential ACE inhibitors. And the flavonoid compounds (5 and 7) showed significant anti-platelet aggregation activities.
  
  
  CONCLUSIONS
  On the basis of the chemical and biological data, the material basis of ACE inhibitory activity for the active part was the phenolic constituents. However, the flavonoid compounds were responsible for the anti-platelet aggregation. The primary structure and activity relationship were also discussed respectively.
authors.affiliation: School of Traditional Chinese Materia Medica, Key Laboratory of Structure-Based Drug Design and Discovery of Ministry of Education Shenyang Pharmaceutical University, Shenyang, China.
authors.forename: Yachao
authors.initials: Y
authors.lastname: Xing
authors.affiliation: XinJiang Institute of Chinese Materia Medica and Ethnodrug, Urumqi, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Liao
authors.affiliation: School of Traditional Chinese Materia Medica, Key Laboratory of Structure-Based Drug Design and Discovery of Ministry of Education Shenyang Pharmaceutical University, Shenyang, China.
authors.forename: Yingzhan
authors.initials: Y
authors.lastname: Tang
authors.affiliation: Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.affiliation: Marine Environmental Engineering College, Dalian Ocean University, Dalian, China.
authors.forename: Chengyu
authors.initials: C
authors.lastname: Tan
authors.affiliation: XinJiang Institute of Chinese Materia Medica and Ethnodrug, Urumqi, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Ni
authors.affiliation: Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China.
authors.forename: Xueqin
authors.initials: X
authors.lastname: Wu
authors.affiliation: School of Traditional Chinese Materia Medica, Key Laboratory of Structure-Based Drug Design and Discovery of Ministry of Education Shenyang Pharmaceutical University, Shenyang, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Li
authors.affiliation: XinJiang Institute of Chinese Materia Medica and Ethnodrug, Urumqi, China.
authors.forename: Xiaoguang
authors.initials: X
authors.lastname: Jia
keywords: ACE inhibitors; Tamarix hohenackeri Bunge; bioassay-directed separation; new triterpenoid lactone; platelet aggregation inhibitors