title: Metabolomic characterization of rhubarb species by capillary electrophoresis and ultra-high-pressure liquid chromatography.
abstract: This study developed CE and ultra-high-pressure LC (UHPLC) methods coupled with UV detectors to characterize the metabolomic profiles of different rhubarb species. The optimal CE conditions used a BGE with 15 mM sodium tetraborate, 15 mM sodium dihydrogen phosphate monohydrate, 30 mM sodium deoxycholate, and 30% ACN v/v at pH 8.3. The optimal UHPLC conditions used a mobile phase composed of 0.05% phosphate buffer and ACN with gradient elution. The gradient profile increased linearly from 10 to 21% ACN within the first 25 min, then increased to 33% ACN for the next 10 min. It took another 5 min to reach the 65% ACN, then for the next 5 min, it stayed unchanged. Sixteen samples of Rheum officinale and Rheum tanguticum collected from various locations were analyzed by CE and UHPLC methods. The metabolite profiles of CE were aligned and baseline corrected before chemometric analysis. Metabolomic signatures of rhubarb species from CE and UHPLC were clustered using principle component analysis and distance-based redundancy analysis; the clusters were not only able to discriminate different species but also different cultivation regions. Similarity measurements were performed by calculating the correlation coefficient of each sample with the authentic samples. Hybrid rhizome was clearly identified through similarity measurement of UHPLC metabolite profile and later confirmed by gene sequencing. The present study demonstrated that CE and UHPLC are efficient and effective tools to identify and authenticate herbs even coupled with simple detectors.
authors.affiliation: School of Pharmacy, College of Medicine, National Taiwan University, Taiwan; The Metabolomics Core Laboratory, Center of Genomic Medicine, National Taiwan University, Taiwan; Graduate Institute of Biomedical Electronic and Bioinformatics, National Taiwan University, Taiwan; Department of Computer Science and Information Engineering, National Taiwan University, Taiwan.
authors.forename: Yufeng Jane
authors.initials: YJ
authors.lastname: Tseng
authors.forename: Chun-Ting
authors.initials: CT
authors.lastname: Kuo
authors.forename: San-Yuan
authors.initials: SY
authors.lastname: Wang
authors.forename: Hsiao-Wei
authors.initials: HW
authors.lastname: Liao
authors.forename: Guan-Yuan
authors.initials: GY
authors.lastname: Chen
authors.forename: Yuan-Ling
authors.initials: YL
authors.lastname: Ku
authors.forename: Wei-Cheng
authors.initials: WC
authors.lastname: Shao
authors.forename: Ching-Hua
authors.initials: CH
authors.lastname: Kuo
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods; D016000:Cluster Analysis; D019075:Electrophoresis, Capillary / Q000379:methods*; D055442:Metabolome; D055432:Metabolomics / Q000379:methods*; D025341:Principal Component Analysis; D012250:Rheum / Q000737:chemistry / Q000378:metabolism*
keywords: Capillary electrophoresis; Chemometric analysis; Metabolite profiling; Rhubarb; Ultra-high-pressure liquid chromatography