title: [Study on extraction process of available components of tea].
abstract: OBJECTIVE
  To investigate the optimum ethanol extraction process conditions for the available components in the tea - Catechines (CT) including Epigallo catechin gallate (EGCG) and Caffeine (CF).
  
  
  METHODS
  The content of EGCG, CT and CF, extraction rate, DPPH * Free radical scavenging capacity were chosen as the assessment indexes. With the alcohol ratio (A), solid-liquid ratio (B) and reflux time (C) as investigation factors, the optimum ethanol extraction process of the available components from tea was determined by L9 (3(4)) orthogonal experimental design.
  
  
  RESULTS
  It would obtain different extraction conditions to analyze the assessment indexes depending on the different extraction purposes. For the purpose of CT, the contents of EGCG and CT, extraction rate and DPPH * Free radical scavenging capacity were chosen as the assessment indexes, the optimum extraction conditions were selected as follows: the ratio of raw material to 75% alcohol was 1: 12, the reflux time was 30 minutes and extraction times were three; For the purpose of CF, the content of CF and extraction rate were chosen as the assessment indexes, the optimum extraction conditions were selected as follows: the ratio of raw material to 60% alcohol was 1: 12, the reflux time was 30 minutes and extraction times were three; For the purpose of integrated extraction, the contents of CT and CF, extraction rate and DPPH * Free radical scavenging capacity were chosen as the assessment indexes, the optimum extraction conditions were selected as follows: the ratio of raw material to 60% alcohol was 1: 8, the reflux time was 30 minutes and extraction times were three.
  
  
  CONCLUSIONS
  The optimum extraction process in order to attain different purposes can give a reference to the research of a new medicine and industry production.
authors.affiliation: Key Laboratory of Chemistry and Quality for Traditional Chinese Medicines of the College of Gansu Province, Department of Pharmacy, Lanzhou 730000, China. bqq230@163.com
authors.forename: Qing-Qing
authors.initials: QQ
authors.lastname: Bai
authors.forename: Yong-Feng
authors.initials: YF
authors.lastname: Liu
authors.forename: Mei
authors.initials: M
authors.lastname: Guo
authors.forename: Jian-Xi
authors.initials: JX
authors.lastname: Zhao
authors.forename: Tian-Cai
authors.initials: TC
authors.lastname: Zhang
authors.forename: Duo-Long
authors.initials: DL
authors.lastname: Di
mesh_terms: D000975:Antioxidants / Q000302:isolation & purification / Q000494:pharmacology; D002110:Caffeine / Q000032:analysis / Q000302:isolation & purification* / Q000494:pharmacology; D002392:Catechin / Q000032:analysis / Q000302:isolation & purification* / Q000494:pharmacology; D000431:Ethanol; D017665:Hydroxyl Radical / Q000378:metabolism; D012997:Solvents / Q000737:chemistry; D013662:Tea / Q000737:chemistry*; D013678:Technology, Pharmaceutical / Q000379:methods*; D013696:Temperature; D013997:Time Factors
chemical_list: D000975:Antioxidants; D012997:Solvents; D013662:Tea; D017665:Hydroxyl Radical; D002110:Caffeine; D000431:Ethanol; D002392:Catechin