Multi-component pharmacokinetics assessment of Artemisia annua L. in rats based on LC-ESI-MS/MS quantification combined with molecular docking

Abstract

Artemisia annua L. ( A. annua ) has been used as herbal medicine in China for thousands of years for clearing deficiency heat, treating malaria and removing jaundice. A rapid, sensitive and specific liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC–ESI–MS/MS) method was developed, validated, and successfully used for simultaneous quantification of the active components in rat plasma after oral administration of A. annua extract. Molecular docking of each component with drug metabolizing enzymes was carried out to explore the effect of each component on CYP-mediated drug metabolism. Two coumarins (scopolin (SPL) and scopoletin (SPLT)), three flavonoids (rutin (RUT), chrysosplenol D (CHD), casticin (CAS)) and three sesquiterpenes (arteannuin B (ARN), dihydroartemisinic acid (DARM) and artemisinic acid (ARM)) were detected in rat plasma after oral administration. CHD and CAS were rapidly absorbed into rat blood with the T max values of 0.11 ± 0.04 h and 0.13 ± 0.05 h, respectively. Their half-lives (t 1/2 2.68 ± 3.62 h and 0.33 ± 0.07 h) were shorter. SPLT were also rapidly absorbed into the blood (T max 0.15 ± 0.03 h), but exhibited a longer half-life (t 1/2 6.53 ± 1.84 h), indicating that it could be effective in vivo for a longer period of time. The peak time of SPL, RUT, DARM and ARM ranged from 1 ∼ 4 h, demonstrating that they could maintain considerable concentrations for a longer time. ARN showed strong enterohepatic circulation in rats, leading to slower onset time and longer effect. A few components including SPLT, CHD, CAS and ARN could be metabolized into their corresponding II phase metabolites combining with glucuronic acid or sulfuric acid. RUT could decompose its glycosyl to generate genin. The molecular docking results indicated that those flavonoids and coumarins of A. annua interacting with CYPs mainly through hydrogen bonding and π-π stacking had better CYP450 enzyme binding ability than the sesquiterpenoids, which were easier to induce drug interactions. This study presented an integrated strategy for investigating the pharmacokinetic behaviors of eight components in A. annua and laid the foundation for revealing the mechanism of action of A. annua in the organism.