Biotransformation of isoimperatorin by rat liver microsomes and its quantification by LC-MS/MS method.

The aim of the present research was to establish a comprehensive strategy to identify the metabolites of isoimperatorin after biotransformation with rat liver microsomes in vitro, and further describe metabolic kinetic characteristics of isoimperatorin and its main metabolites. Utilizing liquid chromatography with time of flight mass spectrometry (LC-TOF-MS), 18 metabolites (M 1-18) were characterized according to the typical fragment ions and literature data. Among them, M-2, 3, 5, 9, 10, and 15 were new compounds. To further verify structures of the metabolites, five main metabolites were obtained from the magnifying biotransformation incubation system, and their chemical structures were elucidated as 8-hydroxyoxypeucedanin (M-3), hydroxypeucedanin hydrate (M-4), E-5-(4-hydroxy-3-methyl-2-alkenyloxy)-psoralen (M-11), Z-5-(4-hydroxy-3-methyl-2-alkenyloxy)-psoralen (M-12), and oxypeucedanin (M-16) by various spectroscopy methods including IR, MS and NMR. A simple new liquid chromatography with triple quadrupole tandem mass spectrometry (LC-QqQ-MS) method was developed for the simultaneous determination of isoimperatorin and its main metabolites. The analysis was performed on a Diamonsil™ ODS C18 column with acetonitrile-water containing 0.1% formic acid as mobile phase. Total run time was 20.0 min. The results suggested that the method we exhibited was successfully applied for analysis of isoimperatorin and its metabolites. The study provides essential data for proposing metabolite pathway and further pharmacological study of isoimperatorin.

Pharmacokinetic study of isoquercitrin in rat plasma after intravenous administration at three different doses

The aim of this study is to develop a simple and specific HPLC method using vitexin as the internal standard to investigate the pharmacokinetics of isoquercitrin (ISOQ) after three different doses administrated intravenously to rats. The pharmacokinetic parameters were calculated by both compartmental and non-compartmental approaches. The results showed that ISOQ fitted a three-compartment open model. The values of AUC increased proportionally within the range of 5-10 mg·kg-1. Moreover, a half-life, b half-life, ªCL, MRT0-t and MRT0→∞ of ISOQ in rats showed significant differences between 20 mg·kg-1 and other doses, indicating that ISOQ presented dose-dependent pharmacokinetics in the range of 5-10 mg·kg-1 and non-linear pharmacokinetics at higher doses.

O objetivo deste estudo é desenvolver um método simples e específico de HPLC usando vitexina como padrão interno para investigar a farmacocinética do isoquercitrina (ISOQ) após três doses diferentes administradas por via intravenosa a ratos. Os parâmetros farmacocinéticos foram calculados pelas abordagens compartimental e não compartimental. Os resultados mostraram que ISOQ se encaixa no modelo de três compartimentos. Os valores de AUC aumentaram proporcionalmente na faixa de 5-10 mg·kg-1. Além disso, a meia-vida, b meia-vida, ªCL, MRT0-t and MRT0→∞ de ISOQ em ratos mostraram diferenças significativas entre 20 mg·kg-1 e outras doses, o que significa que ISOQ apresenta farmacocinética dose-dependente no intervalo de 5-10 mg·kg-1 e farmacocinética não linear em doses mais elevadas.

HPLC method for the simultaneous determination of four compounds in rat plasma after intravenous administration of Portulaca oleracea L. extract

The objective of the present study was to develop a simple and selective HPLC method for the simultaneous determination of hesperidin (HP), caffeic acid (CA), ferulic acid (FA) and p-coumaric acid (p-CA) in rat plasma after intravenous administration of Portulaca oleracea L. extract (POE). With the hyperoside as the internal standard, the sample pretreatment procedure involved simple single-step extraction with methanol of 0.2 mL plasma. The mobile phase consisted of methanol-acetonitrile-tetrahydrofuran-0.5% glacial acetic acid (5:3:18:74, v/v/v/v). The calibration curves were linear over the range of 0.1-25 µg mL-1, 0.1-25 µg mL-1, 0.1-25 µg mL-1and 0.015-3 µg mL-1 for HP, CA, FA and p-CA, respectively. The method developed was suitable for the pharmacokinetic study of HP, CA, FA and p-CA in rats after intravenous administration of POE.

O objetivo do estudo foi desenvolver um método simples e específico de HPLC para a determinação simultânea de hesperidina (HP), ácido caféico (CA), ácido ferúlico (FA) e ácido p-cumárico (p-CA) em plasma de rato após a administração intravenosa de extrato Portulaca oleracea L. (POE) empregando hyperosídeo como padrão interno de referência. Metanol foi empregado para os analitos em plasma (0,2 mL). A fase móvel isocrática foi composta por metanol-acetonitrila-tetraidrofurano-0,5% ácido acético glacial (5:3:18:74, v/v/v/v). Curvas de calibração foram lineares na faixa de concentração de 0,1-25 µg mL-1, 0,1-25 µg mL-1, 0,1-25 µg mL-1 e 0,015-3 µg mL-1 para HP, CA, FA e p-CA, respectivamente. O método desenvolvido foi adequado para estudo farmacocinético de HP, CA, FA e p-CA em ratos após a administração intravenosa de POE.