title: A UPLC-MS/MS Method for Simultaneous Determination of Free and Total Forms of a Phenolic Acid and Two Flavonoids in Rat Plasma and Its Application to Comparative Pharmacokinetic Studies of Polygonum capitatum Extract in Rats.
abstract: The principal active constituents ofPolygonum capitatumare phenolic acids and flavonoids, such as gallic acid, quercitrin, and quercetin. The aim of this study was to develop and validate a method to determine the three constituents and the corresponding conjugated metabolites ofPolygonum capitatumin vivo and to conduct pharmacokinetic studies on the herb, a well-known Miao medicinal plant in China. Gallic acid, quercitrin, and quercetin were analysed by ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS). Protein precipitation in plasma samples was performed using methanol. For the determination of total forms of analytes, an additional process of hydrolysis was conducted using β-glucuronidase and sulphatase. The analytes were separated on a BEH C18column (50 mm × 2.1 mm; i.d., 1.7 μm) and quantified by multiple reaction monitoring (MRM) mode. The linear regression showed high linearity over a 729-fold dynamic range for the three analytes. The relative standard deviations of intra- and inter-day measurements were less than 9.5%, and the method was accurate to within -11.1% to 12.5%. The extraction recoveries for gallic acid, quercitrin, and quercetin were 94.3%-98.8%, 88.9%-98.8%, and 95.7%-98.5%, respectively. All samples were stable under short- and long-term storage conditions. The validated method was successfully applied to a comparative pharmacokinetic study of gallic acid, quercitrin, and quercetin in their free and total forms in rat plasma. The study revealed significantly higher exposure of the constituents in total forms for gallic acid and quercetin, while quercitrin was detected mainly in its corresponding free form in vivo. The established method was rapid and sensitive for the simultaneous quantification of free and total forms of multiple constituents ofPolygonum capitatumextract in plasma.
authors.affiliation: Provincial Key Laboratory of Pharmaceutics in Guizhou Province, Guizhou Medical University, 4 Beijing Road, Guiyang 550004, China. mailofhy@126.com.|School of Pharmacy, Guizhou Medical University, 4 Beijing Road, Guiyang 550004, China. mailofhy@126.com.|National Engineering Research Center of Miao's Medicines, 4 Beijing Road, Guiyang 550004, China. mailofhy@126.com.
authors.forename: Yong
authors.initials: Y
authors.lastname: Huang
authors.affiliation: School of Pharmacy, Guizhou Medical University, 4 Beijing Road, Guiyang 550004, China. sunhuiyuanshy@163.com.
authors.forename: Hui-Yuan
authors.initials: HY
authors.lastname: Sun
authors.affiliation: School of Pharmacy, Guizhou Medical University, 4 Beijing Road, Guiyang 550004, China. qinxiaoli2017@163.com.
authors.forename: Xiao-Li
authors.initials: XL
authors.lastname: Qin
authors.affiliation: School of Pharmacy, Guizhou Medical University, 4 Beijing Road, Guiyang 550004, China. liyongjun026@126.com.|Engineering Research Center for the Development and Application of Ethnic Medicine and TCM, Ministry of Education, Guizhou Medical University, 4 Beijing Road, Guiyang 550004, China. liyongjun026@126.com.
authors.forename: Yong-Jun
authors.initials: YJ
authors.lastname: Li
authors.affiliation: Provincial Key Laboratory of Pharmaceutics in Guizhou Province, Guizhou Medical University, 4 Beijing Road, Guiyang 550004, China. lshangg@163.com.|School of Pharmacy, Guizhou Medical University, 4 Beijing Road, Guiyang 550004, China. lshangg@163.com.
authors.forename: Shang-Gao
authors.initials: SG
authors.lastname: Liao
authors.affiliation: Provincial Key Laboratory of Pharmaceutics in Guizhou Province, Guizhou Medical University, 4 Beijing Road, Guiyang 550004, China. gzp4012607@126.com.|School of Pharmacy, Guizhou Medical University, 4 Beijing Road, Guiyang 550004, China. gzp4012607@126.com.
authors.forename: Zi-Peng
authors.initials: ZP
authors.lastname: Gong
authors.affiliation: Provincial Key Laboratory of Pharmaceutics in Guizhou Province, Guizhou Medical University, 4 Beijing Road, Guiyang 550004, China. 18798090340@163.com.|School of Pharmacy, Guizhou Medical University, 4 Beijing Road, Guiyang 550004, China. 18798090340@163.com.|National Engineering Research Center of Miao's Medicines, 4 Beijing Road, Guiyang 550004, China. 18798090340@163.com.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Provincial Key Laboratory of Pharmaceutics in Guizhou Province, Guizhou Medical University, 4 Beijing Road, Guiyang 550004, China. ylwang_gmc@163.com.|School of Pharmacy, Guizhou Medical University, 4 Beijing Road, Guiyang 550004, China. ylwang_gmc@163.com.
authors.forename: Yong-Lin
authors.initials: YL
authors.lastname: Wang
authors.affiliation: School of Pharmacy, Guizhou Medical University, 4 Beijing Road, Guiyang 550004, China. gywam100@163.com.|Engineering Research Center for the Development and Application of Ethnic Medicine and TCM, Ministry of Education, Guizhou Medical University, 4 Beijing Road, Guiyang 550004, China. gywam100@163.com.
authors.forename: Ai-Min
authors.initials: AM
authors.lastname: Wang
authors.affiliation: School of Pharmacy, Guizhou Medical University, 4 Beijing Road, Guiyang 550004, China. Yanyu626@126.com.|Engineering Research Center for the Development and Application of Ethnic Medicine and TCM, Ministry of Education, Guizhou Medical University, 4 Beijing Road, Guiyang 550004, China. Yanyu626@126.com.
authors.forename: Yan-Yu
authors.initials: YY
authors.lastname: Lan
authors.affiliation: Provincial Key Laboratory of Pharmaceutics in Guizhou Province, Guizhou Medical University, 4 Beijing Road, Guiyang 550004, China. mailofzl@126.com.|School of Pharmacy, Guizhou Medical University, 4 Beijing Road, Guiyang 550004, China. mailofzl@126.com.
authors.forename: Lin
authors.initials: L
authors.lastname: Zheng
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D005707:Gallic Acid / Q000097:blood* / Q000737:chemistry / Q000493:pharmacokinetics; D008297:Male; D010936:Plant Extracts / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry; D010949:Plasma / Q000737:chemistry; D028502:Polygonum / Q000737:chemistry*; D011794:Quercetin / Q000031:analogs & derivatives* / Q000097:blood* / Q000737:chemistry / Q000493:pharmacokinetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D053719:Tandem Mass Spectrometry
chemical_list: D010936:Plant Extracts; C012526:quercitrin; D005707:Gallic Acid; D011794:Quercetin
keywords: Polygonum capitatum extract; UPLC-ESI-MS/MS; flavonoids; hydrolysis; pharmacokinetics; phenolic acids