title: Focused microwave-assisted solvent extraction and HPLC determination of effective constituents in Eucommia ulmodies Oliv. (E. ulmodies).
abstract: A new focused microwave-assisted solvent extraction method using water as solvent has been developed for leaching geniposidic and chlorogenic acids from Eucommia ulmodies Oliv. The extraction procedures were optimized using a two indexes orthogonal experimental design and graphical analysis, by varying irradiation time, solvent volume, solvent composition and microwave power. The optimum extraction conditions were obtained: for geniposidic acid, 50% micorwave power, 40s irradiation, and 80% (v/v) aqueous methanol as extraction solvent (20mlg(-1) sample); and for chlorogenic acid, 50% micorwave power, 30s irradiation, and 20% aqueous methanol (20mlg(-1) sample). The composition of the extraction solvent was optimized and can be directly used as the mobile phase in the HPLC separation. Quantification of organic acids was done by HPLC at room temperature using Spherigel C(18) chromatographic column (250 mm x4.6 mm , i.d. 5mum), the methanol:water:acetic acid (20:80:1.0, v/v) mobile phase and UV detection at 240nm. The R.S.D. of the extraction process for geniposidic and chlorogenic acid were 3.8 and 4.1%, respectively.
authors.affiliation: State Key Laboratory of Chemo/Biological Sensing & Chemometrics, Hunan University, Changsha 410082, PR China; College of Resources and Environmental Sciences, Jishou University, Hunan Jishou 416000, PR China.
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.forename: Bo
authors.initials: B
authors.lastname: Chen
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Zhang
authors.forename: Shouzhuo
authors.initials: S
authors.lastname: Yao