Differential Effects of Components in Artemisia annua Extract on the Induction of Drug-Metabolizing Enzyme Expression Mediated by Nuclear Receptors

Abstract

Artemisia annua tea is a popular dosage form used to treat and prevent malaria in some developing countries. However, repeated drinking leads to an obviously decreased efficacy, which may be related to the induction of metabolizing enzymes by artemisinin. In the present study, the ability of different components in A. annua to activate the pregnane X receptor and constitutive androstane receptor was evaluated by the dual luciferase reporter gene system. The changes in mRNA and protein expression of CYP3A4 and CYP2B6 were determined by quantitative real-time PCR and Western blotting. Results showed that in the pregnane X receptor-mediated CYP3A4 reporter gene system, chrysosplenetin and arteannuin B exhibited a weak induction effect on pregnane X receptor wt, while arteannuin A had a strong induction effect on pregnane X receptor wt and pregnane X receptor 370 and a weak induction effect on pregnane X receptor 163. In the pregnane X receptor-mediated CYP2B6 reporter gene system, arteannuin A had a moderate induction effect on pregnane X receptor wt and pregnane X receptor 379, and a weak induction effect on pregnane X receptor 403, while arteannuin B had a weak induction effect on pregnane X receptor wt and pregnane X receptor 379. Arteannuin A had a strong induction effect on constitutive androstane receptor 3 in constitutive androstane receptor-mediated CYP3A4/2B6 reporter gene systems, while arteannuin B showed a weak induction effect on constitutive androstane receptor 3 in the constitutive androstane receptor-mediated CYP2B6 reporter gene system. The mRNA and protein expressions of CYP3A4 and CYP2B6 were increased when the pregnane X receptor or constitutive androstane receptor was activated. Various components present in A. annua differentially affect the activities of pregnane X receptor isoforms and the constitutive androstane receptor, which indicates the possibility of a drug-drug interaction. This partly explains the decline in efficacy after repeated drinking of A. annua tea.

Artemisia extracts differ from artemisinin effects on human hepatic CYP450s 2B6 and 3A4 in vitro

“…The present study used traditional tea infusions and showed that in contrast to ART alone, the infusions of A. annua and A. afra not only inhibited enzymatic activity of CYP3A4 and CYP2B6, but also inhibited ART-driven induction of CYP2B6 mRNA transcripts. Zhang et al (Zhang et al, 2020) previously showed about a five-fold induction of CYP3A4 compared to RIF when ART increased from 1 to 100 µM. However, we saw no significant change with increasing ART-delivered A. annua SAM.…”

“…For example, Hoekstra et al (Hoekstra et al, 2011) showed that DMSO reduced total protein by ~60% in HepaRG cells. There are other reports of such solvent variations on CYP3A4 protein levels; Zhang et al showed that the solvent, CITCO, used in studies involving constitutive androstane receptor (CAR) increased CYP3A4 protein levels by ~30% compared to DMSO (Zhang et al, 2020).…”

“…However, the former used P450-Glo with HLMs while the latter used HLMs with CYP2B6-and CYP3A4-specific substrates measured by LCMS. In another instance, Zhang et al (Zhang et al, 2020) did not measure enzyme activity and instead used CYP2B6 and CYP3A4 luciferase reporter gene plasmids transfected into HepG2 cells and a Promega kit that converts luminometer readings to gene expression levels; they also suggested that the Cai et al (Cai et al, 2017) discrepancy could be attributed to differences in study design and determination of activity. Such discrepancies in data comparisons are challenging and remain to be resolved using uniform comparative methods.…”

Nontargeted metabolomics integrated with1H NMR and LC–Q‐TOF–MS/MS methods to depict a more comprehensive metabolic profile in response to chrysosplenetin and artemisinin co‐treatment against artemisinin‐sensitive and ‐resistantPlasmodium bergheiK173

“…Our lab purified a polymethoxylated flavonol named chrysosplenetin (CHR) from ART industrial extraction waste using Artemisia annua L. leaves as raw materials and discovered that when the ratio between ART and CHR was 1:2, the anti‐malarial effects were enhanced significantly vs. ART alone (Li et al, 2019; Wei et al, 2015). Further studies in our laboratory indicated that CHR can improve the bioavailability of ART by inhibiting liver metabolic enzyme CYP3a, which plays a role in ART metabolism, and by downregulating P‐glycoprotein (P‐gp), a principal multidrug resistance protein, suggesting that CHR might be a potent small‐molecule inhibitor of ART multidrug resistance (Ma, Wei, et al, 2017; Ma, Zhang, et al, 2017; Zhang et al, 2020; Wei et al, 2015; Zhang et al, 2017; Yang et al, 2016). Recently, it was reported that CHR showed a good in vitro half‐maximum inhibitory concentration (IC 50 , 3.78 μ m ) and selectivity index (15.26), and was identified as a potential inhibitor of P. falciparum multiplication (Banzragchgarav et al, 2021), which is consistent with our previous work.…”