The acute toxic effect of Chinese medicine Fuzi is exacerbated in kidney yang deficiency mice due to metabolic difference.

ETHNOPHARMACOLOGICAL RELEVANCE: The proper application of toxic medicines is one of the characteristics of traditional Chinese medicines, and the use of traditional Chinese medicines follows the principle of dialectical treatment. It is necessary to combine different "syndrome" or "disease" states with the toxicity of traditional Chinese medicines to form a reliable toxicity evaluation system. Fuzi, the lateral root of Aconitum carmichaelii Debx, is recognized as a panacea for kidney yang deficiency syndrome, however, its toxic effects significantly limit its clinical application. AIM OF THE STUDY: Herein, our research aimed to explore the toxic effects of Fuzi on syndrome models, and tried to reveal the underlying mechanisms. MATERIALS AND METHODS: Firstly, the mouse model of kidney yang deficiency syndrome was established through intramuscular injection of 25 mg/kg hydrocortisone per day for 10 consecutive days. Then, the acute toxicity of Fuzi in normal mice and kidney yang deficiency model mice was explored. Finally, the plasma metabolite concentrations and liver CYP3A4 enzyme activity were analyzed to reveal the possible mechanisms of the different pharmacological and toxicological effects of Fuzi in individuals with different physical constitutions. RESULTS: It was found that the treatment with Fuzi (138 g/kg) had serious toxic effects on kidney yang deficiency mice, leading to the death of 80% of the mice, whereas it showed no lethal toxicity in normal mice. This indicates that Fuzi induced greater toxicity in kidney yang deficiency mice than in normal ones. The liver CYP3A4 enzyme activity in kidney yang deficiency mice was decreased by 20% compared to the controls, resulting in slower metabolism of the toxic diester diterpenoid alkaloids in Fuzi. CONCLUSION: In conclusion, our study showed that changes of the metabolic enzyme activity in individuals with different syndromes led to different toxic effects of Chinese medicines, emphasizing the crucial importance of considering individual physical syndromes in the clinical application of traditional Chinese medicine, and the significance of conducting safety evaluations and dose predictions on animal models with specific syndromes for traditional Chinese medicines.

Herba Epimedii and Increased Opioid Cravings While on Buprenorphine: A Case Report.

Herba Epimedii, commonly known as yin yang huo, inyokaku, and horny goat weed, is a traditional Chinese herbal medicine utilized for treating osteoporosis and enhancing libido. Studies conducted in vitro have demonstrated that Herba Epimedii interacts with the enzyme cytochrome P450 3A4 (CYP3A4). This interaction poses a potential risk for drug-drug interactions, particularly with medications metabolized by CYP3A4, such as buprenorphine. This paper presents a case of a patient experiencing exacerbated opioid cravings following the initiation of Herba Epimedii. This is the first reported case supporting this interaction, emphasizing the necessity of screening for alternative medicines in patients undergoing medication-assisted treatments for opioid use disorder.

Effects of WuZhi preparations on tacrolimus in pediatric and adult patients carrying the CYP3A5*1 allele of heart transplant during the early period after transplantation.

AIM: Wuzhi preparations (WZP) are commonly administrated with tacrolimus (TAC) in China to improve the liver function and increase the exposure of TAC. This study aims to investigate the effects of WZP on TAC in pediatric heart transplantation (HTx) patients carrying the CYP3A5*1 allele during the early period after transplantation and also make a comparison with these effects in adult recipients. METHODS: A total of 81 recipients with CYP3A5*1 allele were included and divided into the pediatric group (n = 29) and adult group (n = 52). The changes in TAC dose-corrected trough blood concentrations (C0 /D), dose requirement as well as intra-patient variability(IPV) of C0 /D after co-therapy with WZP were evaluated. RESULTS: The TAC C0 /D was significantly increased 1.7 and 1.8 times after co-administration of WZP in the pediatric and adult groups, respectively. We further analyzed the pediatric patients, found that no statistical difference was observed in TAC C0 /D before and after co-therapy with WZP in children <6 years old. The changes of C0 /D increased with the dose of the active ingredient (Schisantherin A) in adult patients, but not in pediatric patients. TAC IPV was reduced by 10.5% in pediatric patients and 4.8% in adult patients when co-administrated with WZP. Furthermore, after taking WZP, the AST and TB were dramatically lowered in pediatric recipients. CONCLUSION: Our study is the first attempt to demonstrate the effects of WZP on TAC in pediatric HTx recipients. By comparing these effects to those observed in adult recipients, valuable insights can be gained regarding the efficacy and potential benefits of WZP in the pediatric population.

Computational exploration of microsomal cytochrome P450 3A1 enzyme modulation by phytochemicals of Cichorium intybus L.: Insights into drug metabolism.

Drug metabolism plays a crucial role in drug fate, including therapeutic inactivation or activation, as well as the formation of toxic compounds. This underscores the importance of understanding drug metabolism in drug discovery and development. Considering the substantial costs associated with traditional drug development methods, computational approaches have emerged as valuable tools for predicting the metabolic fate of drug candidates. With this in mind, the present study aimed to investigate the potential mechanisms underlying the modulation of microsomal cytochrome P450 3A1 (CYP3A1) enzyme activity by various phytochemicals found in Cichorium intybus L., commonly known as chicory. To achieve this goal, several in silico methods, including molecular docking and molecular dynamics (MD) simulation, were employed to explore computationally the microsomal CYP3A1 enzyme. Schrodinger software was utilized for the molecular docking study, which involved the interaction analysis between CYP3A1 and 28 phytoconstituents of Cichorium intybus. Virtual screening of 28 compounds from chicory led to the identification of the top five ranked compounds. These compounds were evaluated for drug-likeness properties, pharmacokinetic profiles, and predicted binding affinities to CYP3A1. Caffeoylshikimic acid and cichoric acid emerged as promising candidates due to their favorable characteristics, including good oral bioavailability and high binding affinities to CYP3A1. Molecular dynamics simulations were conducted to assess the stability of caffeoylshikimic acid within the CYP3A1 binding pocket. The results demonstrated that caffeoylshikimic acid maintained stable interactions with the enzyme throughout the simulation, suggesting its potential as an effective modulator of CYP3A1 activity. The findings of this study have the potential to provide valuable insights into the complex molecular mechanisms by which Cichorium intybus L. acts on hepatocytes and modulates CYP3A1 enzyme expression or activity. By elucidating the impact of these phytochemicals on drug metabolism, this research contributes to our understanding of how chicory may interact with drugs and influence their efficacy and safety profiles.

Selection and evaluation of quality markers for the regulation of PXR-CYP3A4/FXR-LXRα by Exocarpium Citri Grandis for the treatment of hyperlipidaemia with dispelling blood stasis and removing phlegm.

Hyperlipidaemia is described as "excessive phlegm" and "blood stasis" in the classic theory of traditional Chinese medicine. Exocarpium Citri Grandis has the effect of dispelling blood stasis and removing phlegm, which can better meet the treatment needs of this disease. However, there is still a lack of focus and depth in the study of the chemical composition of this medicine, and the correlation between the study of relevant medicinal substances and the efficacy of dispelling stasis and removing phlegm is insufficient. To address this issue, this study was carried out to validate the overall efficacy and identify and determine the chemical composition of Exocarpium Citri Grandis. The regulatory mechanism of the PXR-CYP3A4/FXR-LXRα pathway and its active ingredients were screened, and a pharmacokinetic study of active ingredients was performed. The obtained multidimensional data were statistically analysed and comprehensively evaluated. The quality marker of Exocarpium Citri Grandis in the treatment of hyperlipidaemia based on the PXR-CYP3A4/FXR-LXRα mechanism to exert the efficacy of dispelling blood stasis and removing phlegm was finally determined. Based on the above experiments, we identified 27 compounds from the ethanol extract of Exocarpium Citri Grandis. Among them, naringenin, meranzin hydrate, apigenin, caffeic acid phenethyl ester, anacardiin, hesperidin and naringin can significantly regulate all or part of the targets in the PXR-CYP3A4/FXR-LXRα pathway. It also has suitable content and pharmacokinetic characteristics in vivo. In conclusion, this study established quality markers to characterize the efficacy of Exocarpium Citri Grandis in dispelling blood stasis and removing phlegm, which provides a scientific basis for the targeted evaluation of the hypolipidaemic activity of this medicinal plant.

Activation of PXR causes drug interactions with Paxlovid in transgenic mice.

Paxlovid is a nirmatrelvir (NMV) and ritonavir (RTV) co-packaged medication used for the treatment of coronavirus disease 2019 (COVID-19). The active component of Paxlovid is NMV and RTV is a pharmacokinetic booster. Our work aimed to investigate the drug/herb-drug interactions associated with Paxlovid and provide mechanism-based guidance for the clinical use of Paxlovid. By using recombinant human cytochrome P450s (CYPs), we confirmed that CYP3A4 and 3A5 are the major enzymes responsible for NMV metabolism. The role of CYP3A in Paxlovid metabolism were further verified in Cyp3a-null mice, which showed that the deficiency of CYP3A significantly suppressed the metabolism of NMV and RTV. Pregnane X receptor (PXR) is a ligand-dependent transcription factor that upregulates CYP3A4/5 expression. We next explored the impact of drug- and herb-mediated PXR activation on Paxlovid metabolism in a transgenic mouse model expressing human PXR and CYP3A4/5. We found that PXR activation increased CYP3A4/5 expression, accelerated NMV metabolism, and reduced the systemic exposure of NMV. In summary, our work demonstrated that PXR activation can cause drug interactions with Paxlovid, suggesting that PXR-activating drugs and herbs should be used cautiously in COVID-19 patients receiving Paxlovid.

Toxicity Derived from Interaction between Natural Compounds and Cancer Therapeutic Drugs Metabolized by CYP3A4: Lessons Learned from Two Clinical Case Reports.

The use of natural compounds and, in general, the use of Complementary and Alternative Medicine (CAM), is growing steadily worldwide, both due to commercial pressure and the increasing use of self-medication and the desire to manage one's own personal health and well-being. Patients facing a cancer diagnosis are also strongly pressured to use these compounds, which are often added to standard therapeutic regimens, that should instead be based solely on diagnostic and therapeutic care pathways (DTCP) or evidence-based medicine (EBM). This study presents two clinical cases of cancer patients who presented to the pharmaceutical consultation service (PCD-Pharmacy Clinical Desk) established at the CRO Institute in Aviano, Italy. Both patients were using natural products along with prescribed chemotherapy. In the first case, a 55-year-old woman diagnosed with bilateral breast cancer with bone metastases, who was using natural compounds based on diosmin, escin (or aescin) and resveratrol in combination with ribociclib anticancer therapy, a severe ADR (neutropenia) was identified as a consequence of the drug-natural product interaction. In the second case, following a detailed medication review by the PCD, we avoided taking a therapeutic treatment (with natural compounds) that in itself could potentially render chemotherapy ineffective in a 57-year-old woman with multiple infiltrating ductal carcinoma of the left breast; the patient was planning to take a natural product containing St. John's Wort tincture and lemon balm tincture, in combination with paclitaxel and trastuzumab. In addition, we describe the corrective actions taken, thus outlining the main objectives of the activity of the PCD's pharmacy counseling service: first, to identify, report, and manage adverse drug reactions (ADRs), and second, to identify therapeutic combinations that present potential risks of toxicity or ineffectiveness of the drug therapy itself.

Herb-drug interaction: Effect of sinapic acid on the pharmacokinetics of dasatinib in rats.

Dasatinib (DAS) is a narrow therapeutic index drug and novel oral multitarget inhibitor of tyrosine kinase and approved for the first-line therapy for chronic myelogenous leukemia (CML) and Philadelphia chromosome (Ph + ) acute lymphoblastic leukemia (ALL). DAS, a known potent substrate of cytochrome (CYP) 3A, P-glycoprotein (Pgp) and breast cancer resistance protein (BCRP) and is subject to auto-induction. The dietary supplementation of sinapic acid (SA) or concomitant use of SA containing herbs/foods may alter the pharmacokinetics as well as pharmacodynamics of DAS, that may probably lead to potential interactions. Protein expression in rat hepatic and intestinal tissues, as well as the in vivo pharmacokinetics of DAS and the roles of CYP3 A2 and drug transporters Pgp-MDR1 and BCPR/ABCG2, suggested a likely interaction mechanism. The single dose of DAS (25 mg/kg) was given orally to rats with or without SA pretreatment (20 mg/kg p.o. per day for 7 days, n = 6). The plasma concentration of DAS was estimated by using Ultra-High-Performance Liquid Chromatography Mass spectrometry (UHPLC-MS/MS). The in vivo pharmacokinetics and protein expression study demonstrate that SA pretreatment has potential to alter the DAS pharmacokinetics. The increase in Cmax, AUC and AUMC proposes increase in bioavailability and rate of absorption via modulation of CYP3 A2, PgP-MDR1 and BCPR/ABCG2 protein expression. Thus, the concomitant use of SA alone or with DAS may cause serious life-threatening drug interactions.

DNA damage and up-regulation of PARP-1 induced by columbin in vitro and in vivo.

Columbin (CLB) is the most abundant (>1.0%) furan-containing diterpenoid lactone in herbal medicine Tinospora sagittate (Oliv.) Gagnep. The furano-terpenoid was found to be hepatotoxic, but the exact mechanisms remain unknown. The present study demonstrated that administration of CLB at 50 mg/kg induced hepatotoxicity, DNA damage and up-regulation of PARP-1 in vivo. Exposure to CLB (10 µM) induced GSH depletion, over-production of ROS, DNA damage, up-regulation of PARP-1 and cell death in cultured mouse primary hepatocytes in vitro. Co-treatment of mouse primary hepatocytes with ketoconazole (10 µM) or glutathione ethyl ester (200 µM) attenuated the GSH depletion, over-production of ROS, DNA damage, up-regulation of PARP-1, and cell death induced by CLB, while co-exposure to L-buthionine sulfoximine (BSO, 1000 µM) intensified such adverse effects resulting from CLB exposure. These results suggest that the metabolic activation of CLB by CYP3A resulted in the depletion of GSH and increase of ROS formation. The resultant over-production of ROS subsequently disrupted the DNA integrity and up-regulated the expression of PARP-1 in response to DNA damage, and ROS-induced DNA damage was involved in the hepatotoxicity of CLB.

Panaxytriol upregulates CYP3A4 expression through the interaction between nuclear regulators and DNA response elements.

ETHNOPHARMACOLOGICAL RELEVANCE: Cytochrome P3A4 (CYP3A4) is a crucial drug-metabolizing enzyme, and its expression is regulated by the pregnane X receptor (PXR), constitutive androstane receptor (CAR), steroid receptor coactivator 1 (SRC-1), and acetyltransferase P300. Panaxytriol is a naturally derived active substance extracted from the roots of Panax ginseng C. A. Mey. which is widely used clinically. Our previous studies have shown that panaxytriol induces CYP3A4 expression through PXR activation, which is antagonized by high CAR expression. However, the underlying mechanism remains unclear. AIM OF THE STUDY: This study aimed to investigate the mechanism of panaxytriol in inducing CYP3A4 expression via interactions between nuclear regulators and DNA response elements. MATERIALS AND METHODS: Immunoprecipitation technique was used to assess the binding levels of PXR and CAR with the coactivators SRC-1 and P300 in HepG2 and Huh-7 cells. Furthermore, chromatin immunoprecipitation assay was used to investigate the PXR and CAR interaction with the CYP3A4 promoter response element ER-6/DR-3. RESULTS: The binding of PXR to SRC-1, P300, and the response elements ER-6 and DR-3 was improved with an increase in panaxytriol concentration (10-80 µM), and the binding affinity was further enhanced upon CAR silencing. The binding of CAR to SRC-1 and the response elements ER-6 and DR-3 was significantly higher at 80 µM panaxytriol, whereas no significant binding was observed between CAR and P300. CONCLUSION: Panaxytriol promoted the recruitment of PXR to SRC-1 and P300, binding to ER-6 and DR-3, and upregulating CYP3A4 expression. Furthermore, an interactive dialogue regulatory mechanism between PXR and CAR was observed.

Effects of Apigenin on Pharmacokinetics of Dasatinib and Probable Interaction Mechanism.

Dasatinib (DAS), a narrow-therapeutic index drug, Bcr-Abl, and Src family kinases multitarget inhibitor have been approved for chronic myelogenous leukemia (CML) and Ph-positive acute lymphocytic leukemia (Ph+ ALL). Apigenin (APG) has a long history of human usage in food, herbs, health supplements, and traditional medicine, and it poses low risk of damage. The concomitant use of APG containing herbs/foods and traditional medicine may alter the pharmacokinetics of DAS, that probably lead to possible herb-drug interactions. The pharmacokinetic interaction of APG pretreatment with DAS in rat plasma following single and co-oral dosing was successfully deliberated using the UPLC-MS/MS method. The in vivo pharmacokinetics and protein expression of CYP3A2, Pgp-MDR1, and BCPR/ABCG2 demonstrate that APG pretreatment has potential to drastically changed the DAS pharmacokinetics where escalation in the Cmax, AUC(0-t), AUMC(0-inf_obs), T1/2, Tmax, and MRT and reduction in Kel, Vd, and Cl significantly in rats pretreated with APG 40 mg/kg, thus escalating systemic bioavailability and increasing the rate of absorption via modulation of CYP3A2, Pgp-MDR1, and BCPR/ABCG2 protein expression. Therefore, the concomitant consumption of APG containing food or traditional herb with DAS may cause serious life-threatening drug interactions and more systematic clinical study on herb-drug interactions is required, as well as adequate regulation in herbal safety and efficacy.

Glycyrrhetinic acid ameliorates diosbulbin B-induced hepatotoxicity in mice by modulating metabolic activation of diosbulbin B.

Exposure to diosbulbin B (DBB), the primary component of the herbal medicine Dioscorea bulbifera L. (DB), can cause liver injury in humans and experimental animals. A previous study found DBB-induced hepatotoxicity was initiated by CYP3A4-mediated metabolic activation and subsequent formation of adducts with cellular proteins. The herbal medicine licorice (Glycyrrhiza glabra L.) is frequently combined with DB used in numerous Chinese medicinal formulas in an effort to protect against DB-elicited hepatotoxicity. Importantly, glycyrrhetinic acid (GA), the major bioactive ingredient in licorice, inhibits CYP3A4 activity. The study aimed to investigate the protection of GA against DBB-induced hepatotoxicity and the underlying mechanism. Biochemical and histopathological analysis showed GA alleviated DBB-induced liver injury in a dose-dependent manner. In vitro metabolism assay with mouse liver microsomes (MLMs) indicated that GA decreased the generation of metabolic activation-derived pyrrole-glutathione (GSH) conjugates from DBB. Toxicokinetic studies demonstrated that GA increased maximal serum concentration (Cmax ) and area under the serum-time curve (AUC) of DBB in mice. In addition, GA attenuated hepatic GSH depletion caused by DBB. Further mechanistic studies showed that GA reduced the production of DBB-derived pyrroline-protein adducts in a dose-dependent manner. In conclusion, our findings demonstrated that GA exerted protective effect against DBB-induced hepatotoxicity, mainly correlated with suppressing the metabolic activation of DBB. Therefore, the development of a standardized combination of DBB with GA may protect patients from DBB-induced hepatotoxicity.

Metabolic Profiling and Investigation of the Modulatory Effect of Fagonia cretica L. Aerial Parts on Hepatic CYP3A4 and UGT2B7 Enzymes in Streptozotocin-Induced Diabetic Model.

Drug-metabolizing enzymes are either boosted or suppressed by diabetes mellitus. This research was designed to explore Fagonia cretica L. aerial parts' impact on CYP3A4 and UGT2B7 activity and their mRNA expression in diabetic rats. Fagonia cretica (F. cretica) dried powder was sequentially extracted with n-hexane, chloroform, ethyl acetate, methanol, and water. The methanol extract and aqueous fraction presented the most significant potential to decrease the concentration of alpha-hydroxyl midazolam, with 176.0 ± 0.85 mg/Kg and 182.9 ± 0.99 mg/Kg, respectively, compared to the streptozotocin (STZ)-induced diabetic group, reflecting the inhibition in CYP3A4 activity. The fold change in mRNA expression of CYP3A4 was decreased significantly by the methanol extract, and the aqueous fraction of F. cretica estimated by 0.15 ± 0.002 and 0.16 ± 0.001, respectively, compared with the diabetic group. Morphine metabolism was significantly increased in rats treated with F. cretica methanol extract and its aqueous fraction, displaying 93.4 ± 0.96 mg/Kg and 96.4 ± 1.27 mg/Kg, respectively, compared with the metabolism of morphine in the diabetic group, which highlights the induction of UGT2B7 activity. The fold change in mRNA expression of UGT2B7 was significantly increased by the methanol extract and the aqueous fraction, estimated at 8.14 ± 0.26 and 7.17 ± 0.23 respectively, compared to the diabetic group. Phytochemical analysis was performed using high-performance liquid chromatography (HPLC), where the methanol extract showed more flavonoids and phenolic compounds compared to the aqueous fraction of F. cretica. The obtained results were further consolidated by molecular docking studies, where quercetin showed the best fitting within the active pocket of CYP3A4, followed by gallic acid, displaying free binding energies (∆G) of -30.83 and -23.12 kcal/mol, respectively. Thus, F. cretica could serve as a complementary medicine with standard anti-diabetic therapy that can modulate the activity of the drug-metabolizing enzymes.

Artemisia annua L. Extracts Irreversibly Inhibit the Activity of CYP2B6 and CYP3A4 Enzymes.

Artemisia annua L. has long been known for its medicinal properties and isolation of ingredients whose derivatives are used for therapeutic purposes. The CYP2B6 and CYP3A4 enzymes belong to a large family of cytochrome P450 enzymes. These enzymes are involved in the metabolism of drugs and other xeonobiotics. It is known that various compounds can induce or inhibit the activity of these enzymes. The aim of this study was to investigate the nature of the inhibitory effect of Artemisia annua extract on CYP2B6 and CYP3A4 enzymes, as well as the type of inhibition, the presence of reversible or pseudo-irreversible inhibition, and the possible heme destruction. The methanolic extract of Artemisia annua showed an inhibitory effect on CYP2B6 (by almost 90%) and CYP3A4 enzymes (by almost 70%). A significant decrease in heme concentration by 46.8% and 38.2% was observed in different assays. These results clearly indicate that the studied plant extracts significantly inhibited the activity of CYP2B6 and CYP3A4 enzymes. Moreover, they showed irreversible inhibition, which is even more important for possible interactions with drugs and dietary supplements.

Evaluation of the Herb-Drug Interaction Potential of Commonly Used Botanicals on the US Market with Regard to PXR- and AhR-Mediated Influences on CYP3A4 and CYP1A2.

In this study, hydroethanolic extracts of 30 top-selling botanicals (herbs) commonly used as ingredients of herbal dietary supplements in the US were screened for their potential to activate the human pregnane X receptor (hPXR) and human aryl hydrocarbon receptor (hAhR) and to increase the activities of hPXR- and hAhR-regulated drug metabolizing cytochrome P450 enzymes (i.e., CYP3A4 and CYP1A2, respectively). Of the 30 botanicals tested, 21 induced PXR and 29 induced AhR transcriptional activities. Out of the 21 botanicals that induced hPXR transcriptional activity, 14 yielded >50% induction in CYP3A4 activity at concentrations ranging from 6 to 60 µg/mL and 16 out of the 29 botanicals that activated hAhR yielded >50% induction in CYP1A2 activity at concentrations ranging from 3 to 30 µg/mL. Moreover, eight botanicals (G. gummi-gutta [garcinia], Hemp [low and high CBD content], H. perforatum [St. John's wort], M. vulgare [horehound], M. oleifera [moringa], O. vulgare [oregano], P. johimbe [yohimbe] and W. somnifera [ashwagandha]) yielded >50% induction in both CYP3A4 and CYP1A2 activity. Herbal products are mixtures of phytoconstituents, any of which could modulate drug metabolism. Our data reveals that several top-selling botanicals may pose herb-drug interaction (HDI) risks via CYP450 induction. While in vitro experiments can provide useful guidance in assessing a botanical's HDI potential, their clinical relevance needs to be investigated in vivo. Botanicals whose effects on hPXR/CYP3A4, and hAhR/CYP1A2 activity were most pronounced will be slated for further clinical investigation.

Impact of Pregnancy and Vitamin A Supplementation on CYP2D6 Activity.

The mechanism of cytochrome P450 2D6 (CYP2D6) induction during pregnancy has not been evaluated in humans. This study assessed the changes in CYP2D6 and CYP3A activities during pregnancy and postpartum, and the effect of vitamin A administration on CYP2D6 activity. Forty-seven pregnant CYP2D6 extensive metabolizers (with CYP2D6 activity scores of 1 to 2) received dextromethorphan (DM) 30 mg orally as a single dose during 3 study windows (at 25 to 28 weeks of gestation, study day 1; at 28 to 32 weeks of gestation, study day 2; and at ≥3 months postpartum, study day 3). Participants were randomly assigned to groups with no supplemental vitamin A (control) or with supplemental vitamin A (10 000 IU/day orally for 3 to 4 weeks) after study day 1. Concentrations of DM and its metabolites, dextrorphan (DX) and 3-hydroxymorphinan (3HM), were determined from a 2-hour post-dose plasma sample and cumulative 4-hour urine sample using liquid chromatography-mass spectrometry. Change in CYP2D6 activity was assessed using DX/DM plasma and urine metabolic ratios. The activity change in CYP3A was also assessed using the 3HM/DM urine metabolic ratio. The DX/DM urine ratio was significantly higher (43%) in pregnancy compared with postpartum (P = .03), indicating increased CYP2D6 activity. The DX/DM plasma ratio was substantially higher in the participants, with an activity score of 1.0 during pregnancy (P = .04) compared with postpartum. The 3HM/DM urinary ratio was significantly higher (92%) during pregnancy, reflecting increased CYP3A activity (P = .02). Vitamin A supplementation did not change CYP2D6 activity during pregnancy; however, plasma all-trans retinoic acid (atRA) concentrations were positively correlated with increased CYP2D6 activity during pregnancy and postpartum. Further research is needed to elucidate the mechanisms of increased CYP2D6 activity during pregnancy.

Effects of breviscapine on cerebral ischemia-reperfusion injury and intestinal flora imbalance by regulating the TLR4/MyD88/NF-κB signaling pathway in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: The plant Erigeron breviscapus (Vant.) Hand.-Mazz.,a Chinese herbal medicine with multiple pharmacological effects and clinical applications, has been traditionally used in the treatment of paralysis caused by stroke and joint pain from rheumatism by the Yi minority people of Southwest China for generations.However, its mechanism involves many factors and has not been fully clarified. AIM OF THE STUDY: Taking intestinal flora as the target, the protective effect of extract(breviscapine) of E. breviscapus on cerebral ischemia and its possible mechanism were discussed from the perspective of brain inflammatory pathway and intestinal CYP3A4, which depends on intestinal flora. MATERIALS AND METHODS: In this study, we first verified the binding ability between major active ingredient of Erigeron breviscapus and the core target TLR4 protein by molecular docking using Vina software.We established a rat model of cerebral ischemia-reperfusion injury in vivo.The neurological function of rats was scored by Bederson score table, the cerebral infarction volume was detected by TTC staining, and the serum NSE level was detected by ELASA. 16S rRNA sequencing was used to detect the intestinal flora of rats in each group.The expression levels of cerebral TLR4/MyD88/NF-κB and CYP3A4 mRNA and protein in different intestinal segments were detected by qRT-PCR and Western blot. RESULTS: Compared with the model group, the neurological injury score, infarct volume and serum NSE concentration of breviscapine low, medium and high dose groups and nimodipine groups decreased significantly. Meanwhile, breviscapine could significantly reduce the expression level of the TLR4/MyD88/NF-κB in brain tissue and CYP3A4 in different intestinal segments of rats with cerebral ischemia-reperfusion injury. In addition, breviscapine also significantly ameliorated intestinal flora dysbiosis of rats with cerebral ischemia-reperfusion injury. CONCLUSIONS: Breviscapine can protect rats from cerebral ischemia-reperfusion injury by regulating intestinal flora, inhibiting brain TLR4/MyD88/NF-κB inflammatory pathway and intestinal CYP3A4 expression.

Discovery and Activity Evaluation of the Inhibitory Effect of Four Kinds of Traditional Chinese Medicine Extracts on the CYP3A4 Enzyme.

BACKGROUND AND OBJECTIVE: Traditional Chinese medicines that have inhibitory effects on the CYP3A4 enzymes were screened and their inhibitory effects were verified with in vitro bioassay. METHODS: The computer virtual screening methods, including the CYP3A4 enzyme pharmacophore model and the molecular docking method, were used to rapidly screen the potential CYP3A4 inhibitors in the Traditional Chinese Medicine Database (TCMD), and then in vitro experiments were conducted to validate the computational data. RESULTS: A total of 413 chemical components in TCMD that have potential inhibitory effects on the CYP3A4 enzyme were screened, and four kinds of traditional Chinese medicines (Abrus precatorius, Andrographis paniculata, Angelica pubescens f. biserrata and Lithospermum erythrorhizon) contained the most potential CYP3A4 inhibitors; The results of the in vitro experiments showed that these four traditional Chinese medicine extracts all had certain degrees of inhibition on the CYP3A4 enzyme, with IC50 values of 5.15, 14.97, 15.2, and 24.21 µg/ml, respectively. CONCLUSION: The extracts of Abrus precatorius, Andrographis paniculata, Angelica pubescens f. biserrata and Lithospermum erythrorhizon had certain inhibitory effects on the CYP3A4 enzyme, and attention should be paid to the possible adverse reactions when they were used in combination with the CYP3A4 enzyme-substrate drugs. A combination of computational approaches might be a useful tool to identify potential inhibitors of the CYP3A4 enzyme from traditional Chinese medicine.

Activation of PXR causes drug interactions with Paxlovid in transgenic mice

Paxlovid is a nirmatrelvir (NMV) and ritonavir (RTV) co-packaged medication used for the treatment of coronavirus disease 2019 (COVID-19). The active component of Paxlovid is NMV and RTV is a pharmacokinetic booster. Our work aimed to investigate the drug/herb-drug interactions associated with Paxlovid and provide mechanism-based guidance for the clinical use of Paxlovid. By using recombinant human cytochrome P450s (CYPs), we confirmed that CYP3A4 and 3A5 are the major enzymes responsible for NMV metabolism. The role of CYP3A in Paxlovid metabolism were further verified in Cyp3a-null mice, which showed that the deficiency of CYP3A significantly suppressed the metabolism of NMV and RTV. Pregnane X receptor (PXR) is a ligand-dependent transcription factor that upregulates CYP3A4/5 expression. We next explored the impact of drug- and herb-mediated PXR activation on Paxlovid metabolism in a transgenic mouse model expressing human PXR and CYP3A4/5. We found that PXR activation increased CYP3A4/5 expression, accelerated NMV metabolism, and reduced the systemic exposure of NMV. In summary, our work demonstrated that PXR activation can cause drug interactions with Paxlovid, suggesting that PXR-activating drugs and herbs should be used cautiously in COVID-19 patients receiving Paxlovid.

The Chinese herb Styrax triggers pharmacokinetic herb-drug interactions via inhibiting intestinal CYP3A.

Human cytochrome P450 3A4 (hCYP3A4) is a predominant enzyme to trigger clinically relevant drug/herb-drug interactions (DDIs or HDIs). Although a number of herbal medicines have been found with strong anti-hCYP3A4 effects in vitro, the in vivo modulatory effects of herbal medicines on hCYP3A4 and their potential risks to trigger HDIs are rarely investigated. Herein, we demonstrate a case study to efficiently find the herbal medicine(s) with potent hCYP3A4 inhibition in vitro and to accurately assess the potential HDIs risk in vivo. Following screening over 100 herbal medicines, the Chinese herb Styrax was found with the most potent hCYP3A4 inhibition in HLMs. In vitro assays demonstrated that Styrax could potently inhibit mammalian CYP3A in liver and intestinal microsomes from both humans and rats. In vivo pharmacokinetic assays showed that Styrax (i.g., 100 mg/kg) significantly elevated the plasma exposure of two CYP3A-substrate drugs (midazolam and felodipine) when midazolam or felodipine was administered orally. By contrast, the plasma exposure of either midazolam or felodipine was hardly affected by Styrax (i.g.) when the victim drug was administered intravenously. Further investigations demonstrated that seven pentacyclic triterpenoid acids (PTAs) in Styrax were key substances responsible for CYP3A inhibition, while these PTAs could be exposed to intestinal tract at relatively high exposure levels but their exposure levels in rat plasma and liver were extremely low. These findings well explained why Styrax (i.g.) could elevate the plasma exposure of victim drugs only when these agents were orally administrated. Collectively, our findings demonstrate that Styrax can modulate the pharmacokinetic behavior of CYP3A-substrate drugs via inhibiting intestinal CYP3A, which is very helpful for the clinical pharmacologists to better assess the HDIs triggered by Styrax or Styrax-related herbal products.