title: Trace enrichment and characterization of polyphenols in Bistort Rhizoma using weak anion-exchange solid phase extraction and high performance liquid chromatography-quadrupole time-of-flight mass spectrometry.
abstract: The analysis of trace constituents in herbal medicines has always been a challenge due to complex matrices and structural diversities. In this work, a pH-sensitive solid phase extraction (SPE) procedure capable of enriching trace polyphenols in Bistort Rhizoma (BR) was proposed and preliminary chemical characterization was accomplished by high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (HPLC-QTOF MS). A weak anion-exchange SPE column packed with divinylbenzene/vinylpyrrolidone bonding quaternary amine group was employed for anionic extraction, and the target fraction was obtained by eluting with acidic methanol (apparent pH 1.9). On the other hand, the MS/MS fragmentation rules of four reference polyphenols in negative ion mode were outlined. Using these rules, a total of 31 polyphenols including 20 benzoyl derivatives and 11 caffeoyl derivatives were screened out from BR extract, of which 26 trace members were found for the first time in this herb. Those findings demonstrated that the anion-exchange SPE could enhance the detection capability and selectivity for plant polyphenols in the LC-MS analysis and the strategy for deducing structures could be applied for analysis of polyphenols in BR and other herbal medicines.
authors.affiliation: State Key Laboratory of Natural Medicines, China Pharmaceutical University, No. 24 Tongjia Lane, Nanjing 210009, People's Republic of China.
authors.forename: Shao-Teng
authors.initials: ST
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Natural Medicines, China Pharmaceutical University, No. 24 Tongjia Lane, Nanjing 210009, People's Republic of China.
authors.forename: Hua
authors.initials: H
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Natural Medicines, China Pharmaceutical University, No. 24 Tongjia Lane, Nanjing 210009, People's Republic of China.
authors.forename: Wen
authors.initials: W
authors.lastname: Gao
authors.affiliation: State Key Laboratory of Natural Medicines, China Pharmaceutical University, No. 24 Tongjia Lane, Nanjing 210009, People's Republic of China. Electronic address: cupli@163.com.
authors.forename: Hui-Jun
authors.initials: HJ
authors.lastname: Li
authors.affiliation: State Key Laboratory of Natural Medicines, China Pharmaceutical University, No. 24 Tongjia Lane, Nanjing 210009, People's Republic of China. Electronic address: liping2004@126.com.
authors.forename: Ping
authors.initials: P
authors.lastname: Li
mesh_terms: D000837:Anion Exchange Resins / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004365:Drugs, Chinese Herbal / Q000737:chemistry*; D013058:Mass Spectrometry / Q000379:methods; D015394:Molecular Structure; D028502:Polygonum / Q000737:chemistry*; D059808:Polyphenols / Q000032:analysis* / Q000737:chemistry; D027343:Rhizome / Q000737:chemistry*; D052616:Solid Phase Extraction / Q000379:methods
chemical_list: D000837:Anion Exchange Resins; D004365:Drugs, Chinese Herbal; D059808:Polyphenols
keywords: Anion-exchange solid phase extraction; Bistort Rhizoma; Chemical characterization; HPLC-QTOF MS; Polyphenols