Compound danshen dripping pills affect the pharmacokinetics of azisartan by regulating the expression of cytochrome P450 2B1, 2C6, and 2C11 in rats

Combination therapies of compound danshen dripping pill (CDDP) and Azilsartan (AZ) represent a promising treatment option in clinical practice in China, but there are no reports on drug-drug interactions between CDDP and AZ. This study investigated the effects of CDDP on the pharmacokinetics of AZ and clarified its potential mechanism. The pharmacokinetic profiles of oral administration of AZ (2 mg/kg) in Sprague-Dawley rats, with or without pre-treatment of CDDP (81, 405, 810 mg/kg/d for 7 d) were investigated using UPLC-MS/MS. The main pharmacokinetic parameters were calculated and compared. The MS analysis was performed in positive ionization mode. The purpose of chromatographic separation of AZ and the internal standard (IS, Valsartan) was finished on a Waters XBridge BEH C18 column (2.1 × 100 mm, 2.5 μm). The mobile phase was acetonitrile and 0.1 % formic acid-water with gradient elution at a flow rate of 0.4 mL/min. The mRNA and protein levels of CYP2B1, CYP2C6, and CYP2C11 in the rat liver were detected by qRT-PCR and western blot, respectively. The results indicated that low, medium and high doses of CDDP significantly increased the C_max (6.47 ± 2.28, 6.51 ± 1.99, 7.04 ± 1.31 vs. 3.30 ± 1.87) of AZ, compared with that in the AZ single-drug group (p<0.05). The AUC_0-t of AZ (47.77 ± 23.41, 50.69 ± 25.46, 54.50 ± 11.57 vs. 26.85 ± 16.79) tended to increase in combination with CDDP. The gene and protein expression levels of CYP2B1, CYP2C6, and CYP2C11 were significantly reduced in the rat liver by CDDP. CDDP may diminish the AZ metabolism in vivo by suppressing the expression of the CYP2B1, CYP2C6, and CYP2C11 enzymes. This observation suggested the occurrence of potential interactions between CDDP and AZ when clinically administered as combination therapy, which may require adjustment of the clinical dose of AZ.

Herb-drug interaction: The effect of Polygonum capitatum extract on pharmacokinetics of levofloxacin in rats

Polygonum capitatum is a traditional medicinal plant of the Miao people and has been used to treat a variety of urological disorders in China for many years. Preparations made from water-soluble P. capitatum extracts, Relinqing® granules, are often used in combination with levofloxacin to treat urinary tract infections, and have demonstrated better clinical efficacy than either drug alone. As there is no information on the pharmacokinetics of both drugs after co-administration, a sensitive and reliable ultra-performance liquid chromatography-tandem mass spectrometry method was developed and validated to study the potential herb-drug interactions between P. capitatum and levofloxacin. This analytical method delivered high levels of specificity, recovery, accuracy, precision and preserved sample stability. When applied to study pharmacokinetic interactions after oral co-administration of P. capitatum extract (1.86 g kg^-1) and levofloxacin (42 mg kg^-1) in rats, the results indicated significant reductions in C_max and AUC_0-24h of levofloxacin, and significant increases in MRT, T_max, CLz/F and Vz/F. Moreover, pretreatment with P. capitatum extract orally did not alter the intravenous pharmacokinetics of levofloxacin. Combined and compared oral pharmacokinetic parameters, suggesting that the interacting targets might localized in the intestine during absorption. Overall, the results revealed a potential herb-drug interaction between P. capitatum and levofloxacin.

Co-administration of Wuzhi tablet (Schisandra sphenanthera extract) alters tacrolimus pharmacokinetics in a dose- and time-dependent manner in rats

ETHNOPHARMACOLOGY RELEVANCE

Tacrolimus is a well-known potent but expensive immunosuppressant. We previously clarified the herb-drug interaction between tacrolimus and Wuzhi tablet (WZ), a prescribed drug of ethanol extract of Schisandra sphenanthera, and showed the ideal effect of WZ on maintaining therapeutic level of tacrolimus and reducing the total drug expense. However, WZ possesses a biphasic effect on regulating CYP3A (the major metabolizing enzyme of tacrolimus), which could induce the mRNA and protein expression after long-term treatment while transiently inhibit the activity of CYP3A. In clinic, clinicians are confused about the relationship between the blood concentration of tacrolimus and the dose and the duration of pretreatment of WZ. Therefore, the effects of the pretreatment time and the dose of WZ on the pharmacokinetics of tacrolimus is urgently needed to be clarified to better combine the use of WZ and tacrolimus in clinic.

AIM OF THE STUDY AND METHOD

This study aimed to investigate the effects of the pretreatment time and the dose of WZ on the pharmacokinetics of tacrolimus in rats.

RESULTS AND CONCLUSIONS

After pretreated rats with WZ for 0, 0.5, 2, 6, 12 or 24 h, the area under the curve (AUC) of tacrolimus was 2.27 ± 0.59, 1.87 ± 1.14, 2.86 ± 0.64, 1.62 ± 0.70, 1.54 ± 1.06 and 1.12 ± 0.69-fold of that of the tacrolimus alone group, respectively. The ratio of AUC of tacrolimus to that of the co-administration group with 0, 62.5, 125, 250, 500 or 750 mg/kg of WZ was 1.00: 1.07: 1.44: 2.60: 2.32: 2.42, respectively. These findings suggested that WZ increased tacrolimus AUC in a pretreatment time- and dose-dependent manner. In line with the in vivo findings, WZ extract inhibited CYP3A activity in a pre-treatment time- and concentration-dependent manner in human liver microsomes. In conclusion, the pharmacokinetics of tacrolimus was significantly affected by the pretreatment time and the dose of WZ. Oral pretreatment with WZ for 0-2 h or co-dosing of 250 mg/kg of WZ most significantly increased the blood concentration of tacrolimus. These findings would be helpful for guiding the reasonable use of WZ and tacrolimus in clinic.

Antioxidant or pro-oxidant and glutathione transferase P1-1 inhibiting activities for Tamarindus indica seeds and their cytotoxic effect on MCF-7 cancer cell line

BACKGROUND

The multidrug resistance (MDR) of cancer cells is a major obstacle to cancer treatment. Glutathione S-transferase Pi (GSTP1-1) catalyzes the conjugation of glutathione with anticancer drugs and therefore reduces their efficacy. Phenolic compounds have the potential to inhibit GST P1-1 activity, which is a promising goal to overcome MDR and increase the efficacy of chemotherapy.

RESULTS

Three fractions (dichloromethane, ethyl acetate, and n-butanol) were prepared from Tamarindus indica seeds to determine their phenolic and flavonoid properties as well as their antioxidant/pro-oxidant properties. The n-butanol fraction displayed the highest levels of phenol ( 378 ± 11.7 mg gallic acid equivalent/g DW) and flavonoids (83 ± 6.0 mg rutin equivalent/g DW). Inhibiting effects on purified GSTP1-1 activity in human erythrocytes (eGST), placenta (pGST), and hGSTP1-1 have been studied. The n-butanol fraction was the most effective in inhibiting eGST, hGSTP1-1, and pGST with IC₅₀ values of 3.0 ± 0.7, 4.85 ± 0.35, and 6.6 ± 1.2 μg/ml, respectively. Cellular toxicity was investigated for the T. indica n-butanol fraction on various human cancerous cell lines. The only ones affected were MCF-7 cell lines (72%) and HePG2 (52%) indicated cytotoxicity. The value of IC₅₀ is 68.5 μg/ml of T. indica n-butanol fraction was observed compared to 1.7 μg/ml tamoxifen in MCF-7 cell lines. The combination of treatment of T. indica extract with the medicinally approved drug tamoxifen had unexpected effects; complete elimination of the cytotoxic inhibition effect of tamoxifen and the plant extract was observed.

CONCLUSIONS

However T. indica extract has a cytotoxic effect on the MCF-7 cell line; in certain situations, plant products can have an opposite effect to the intended drug, which decreases the impact of the drug.

Herb-drug interaction in the protective effect of Alpinia officinarum against gastric injury induced by indomethacin based on pharmacokinetic, tissue distribution and excretion studies in rats

Alpinia officinarum Hance of the Chinese traditional herb for the treatment of emesis, abdominal pain and diarrhea has been used to counteract gastric disease induced by indomethacin in rats without obvious side effects. However, the role of herb-drug interaction between indomethacin and A. officinarum based on pharmacokinetic, tissue distribution and excretion still remains unknown. In this study, an ultra-fast liquid-tandem mass spectrometry (UFLC-MS/MS) method was developed for simultaneous determination of indomethacin and its three metabolites, O-desmethylindomethacin (ODI), deschlorobenzoylindomethacin (NDI) and indomethacin acyl-β-D-glucuronide (IDAβG) by oral administration of indomethacin solution with and without the ethanolic extract of A. officinarum and applied to comparative pharmacokinetic, tissue distribution and excretion studies. Our results clarified that oral administration of A. officinarum produced significant alterations in the pharmacokinetic parameters of indomethacin. And the pharmacokinetic interaction between indomethacin and A. officinarum reduced the systemic exposure of indomethacin and increased its elimination. Tissue distribution results demonstrated that co-administration of A. Officinarum could not reduce the accumulation of indomethacin in the target tissue of the stomach, but could accelerate the excretions of indomethacin and its three metabolites including ODI, NDI and IDAβG in the bile and feces of rats in the excretion study. Therefore, A. Officinarum might have a gastrointestinal protective effect through the interaction role with indomethacin based on the pharmacokinetics and excretion in rats.

Herb-drug interaction of gastrodiae rhizoma on carbamazepine: A pharmacokinetic study in rats

OBJECTIVE

Gastrodiae Rhizoma (GR), is a traditional Chinese Medicine that has been used for neurological disorders, including epilepsy. Epilepsy patients may be treated with adjunctive therapy of GR with antiepileptic drugs (AEDs). In particular, carbamazepine (CBZ) is of high potential to interact with concurrent treatment of Chinese Medicine. This study was to investigate the herb-drug interactions of GR and CBZ, an AED, through pharmacokinetic approach in rats.

METHODS

We adopted a high-performance liquid chromatography (HPLC) system to quantify the plasma level of CBZ and its metabolite (carbamazepine-10, 11-epoxide, CBZE). The method was validated as per instructions under United States Food and Drug Administration (USFDA) guidance. For the herb-drug interaction study, rats were randomly divided into four different treatment groups: single-dose CBZ treatment, single-dose CBZ/GR treatment, 2-week course of CBZ treatment and 2-week course of CBZ/GR treatment.

RESULTS

Our results demonstrated the auto-induction of CBZ metabolization when comparing single-dose with 2-week course of CBZ treatment. Pharmacokinetic interactions were noted in concomitant use of GR with CBZ by comparing two single-dose treatments (CBZ versus CBZ/GR). Our data showed that GR increased the mean residence time (MRT0-t) and the time taken to reach the maximum concentration (Tmax) of CBZ in single-dose of CBZ/GR treatment. The maximum drug concentration (Cmax) of CBZ was reduced in single-dose CBZ/GR treatment. When comparing the 2-week course of CBZ treatment with the 2-week course of CBZ/GR treatment, the MRT0-t and half-life of CBZ were increased. The AUC0-t, the Cmax and the half-life of CBZE were increased.

CONCLUSION

CBZ/GR treatment may reduce the auto-induction of CBZ over 2 weeks. While the reduction of auto-induction could enhance the therapeutic effects of CBZ, it could also lead to an increase in neurological side effects and non-neurological adverse effects. Our results provided preclinical evidence of herb-drug interaction, which may have implications for epilepsy patients treated with GR.

Risk factors associated with the severity of adverse drug reactions by Xiyanping injection: A propensity score-matched analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Xiyanping injection (XYP), extraction of Andrographis paniculate (Andrographis paniculata (Burm. f.) Nees, chuan xin lian), is a Chinese patent medicine approved to treat bronchitis in China. In 2017, safety incidents associated with treatment of XYP began to emerge throughout China. However, the risk factors of severity of adverse reactions by XYP remain uncertain.

AIM OF THE STUDY

To determine risk factors for the severity of XYP-associated adverse drug reactions (ADRs).

MATERIALS AND METHODS

We analyzed a total of 26,317 cases of ADRs linked to the use of XYP injection in the China National Adverse Drug Reaction Monitoring Information System from 2004 to 2017. Data were analyzed with respect to age, gender, ethnicity, previous ADRs, family history of ADRs, dosage specification, medication frequency specification, body weight, route of administration, herb-drug interactions (ribavirin, cefatriaxone, penicillin sodium, ambroxol hydrochloride, clindamycin, cefoxitin sodium, azithromycin, ceftazidime, amoxicillin sodium and clavulanate potassium, levofloxacin, cefazolin sodium pentahydrate, acyclovir) by univariate analysis and multivariate analysis. Propensity score matching was used to compare severity of (general or serious) ADRs.

RESULTS

We included 24,911 cases of general ADRs and 1406 cases of serious ADRs. Univariate analysis identified age (p ​< ​0.001), body weight (p ​< ​0.001), route of administration (p ​= ​0.008), co-administration of XYP with ribavirin (p ​= ​0.031) as risk factors of severity of ADRs. Multivariate analysis identified XYP ​+ ​ribavirin combination (p ​= ​0.048) and age (p ​< ​0.001) as the independent risk factors. Upon propensity score matching, the variables were relatively balanced amongst the two groups of patients with general or severe ADRs, and the level of severity in patients who received treatment of XYP ​+ ​ribavirin increased (p ​= ​0.020).

CONCLUSIONS

Age and co-administration of ribavirin may be potential risk factors for the severity of XYP-associated ADRs. This reminds us to pay more attention to the safety of elderly medication. Minimizing the herb-drug-interaction effects of XYP and ribavirin is a viable treatment target for healthcare professionals in managing serious ADRs amongst patients receiving XYP injection.

No improvement in disclosure of natural health product use to primary care medical doctors in the last 15 years: A survey of naturopathic patients

BACKGROUND

The use of natural health products (NHPs) is common in North America. In 2003, we found that 42% of NHP users had not disclosed this information to their primary care medical doctors (MDs). We repeated our survey in 2018/2019 to explore if the rate of NHP use disclosure had improved.

METHODS

From November 2018-February 2019, a 21-item survey about NHP use and disclosure was administered to adult patients who visited the Robert Schad Naturopathic Clinic in Toronto, Canada.

RESULTS

Almost all patients surveyed were using NHPs (99%), and 46% were using NHPs and prescription medication concurrently. Consistent with our 2003 findings, 42% of respondents who used NHPs did not disclose this information to their MD.

CONCLUSION

Disclosure of NHP use to MDs by naturopathic patients is limited and remained unchanged over the past 15 years. Future research should explore primary care MDs' hesitancy to inquire about patient NHP use.

The effects of oral administration of Cola nitida on the pharmacokinetic profile of metoclopramide in rabbits

BACKGROUND

Cola nitida is commonly chewed in many West African cultures to ease hunger pangs and sometimes for their stimulant and euphoriant qualities. Metoclopramide is a known substrate for P-gp, SULT2A1 and CYP2D6 and studies have revealed that caffeine- a major component of Cola nitida can induce P-glycoprotein (P-gp), SULT2A1 and SULT1A1, hence a possible drug interaction may occur on co-administration. The aim of this study was to investigate the pharmacokinetic interactions of Cola nitida and metoclopramide in rabbits.

METHODS

The study was performed in two stages using five healthy male rabbits with a 1-week washout period between treatments. Stage one involved oral administration of metoclopramide (0.5 mg/kg) alone while in the second stage, metoclopramide (0.5 mg/kg) was administered concurrently with Cola nitida (0.7 mg/kg). Blood samples were collected after each stage at predetermined intervals and analyzed for plasma metoclopramide concentration using HPLC.

RESULTS

Compared with control, the metoclopramide/Cola nitida co-administration produced a decrease in plasma concentration of metoclopramide at all the time intervals except at the 7th hour. The following pharmacokinetic parameters were also decreased: area under the curve (51%), peak plasma concentration (39%), half-life (51%); while an increase in elimination rate constant (113%) and clearance rate (98%) were noted indicating rapid elimination of the drug. A minimal decrease in absorption rate (10%) was also observed.

CONCLUSIONS

The results of this study reveal a possible herb-drug interaction between Cola nitida and metoclopramide.

In vitro inhibitory effects of kaempferitrin on human liver cytochrome P450 enzymes

Context: Kaempferitrinis (KF) is a bioactive flavonoid and possesses numerous pharmacological activities. However, whether KF affects the activity of human liver cytochrome P450 (CYP) enzymes remains unclear. Objective: This study investigates the effects of KF on eight major CYP isoforms in human liver microsomes (HLMs). Materials and methods: In vitro, HLMs were used to investigate the inhibitory effects of KF (100 μM) on the eight human liver CYP isoforms (i.e., 1A2, 3A4, 2A6, 2E1, 2D6, 2C9, 2C19, and 2C8), and corresponding probe substrates were used. Enzyme kinetic studies (0-50 μM of KF) were conducted to determine the inhibition mode of KF on CYP enzymes. Results: The results showed that KF inhibited the activity of CYP1A2, 3A4, and 2C9, with IC₅₀ values of 20.56, 13.87, and 14.62 μM, respectively, but that other CYP isoforms were not affected. Enzyme kinetic studies showed that KF was not only a noncompetitive inhibitor of CYP3A4, but also a competitive inhibitor of CYP1A2 and 2C9, with Ki values of 7.11, 10.24, and 7.58 μM, respectively. In addition, KF is a time-dependent inhibitor for CYP3A4 with K_I/K_inact value of 10.85/0.036 min/μM. Discussion: The in vitro studies of KF with CYP isoforms indicate that KF has the potential to cause pharmacokinetic drug interactions with other co-administered drugs metabolized by CYP1A2, 3A4, and 2C9. Conclusion: It is recommended that KF should not be used with other drugs metabolized by CYP1A2, 3A4, and 2C9. Further clinical studies are needed to evaluate the significance of this interaction.

Effects of Ginkgo leaf tablets on the pharmacokinetics of atovastatin in rats

Context: Ginkgo leaf tablets (GLT), an effective traditional Chinese multi-herbal formula, are often combined with atorvastatin calcium (AC) for treating coronary heart disease in clinic. Objective: This study investigated the effects of GLT on the pharmacokinetics of AC and the potential mechanism. Materials and methods: The pharmacokinetics of AC (oral administered at a dose of 1 mg/kg) with or without pre-treatment of GLT (oral administered at a dose of 80 mg/kg/day for 10 days) were investigated in male Sprague-Dawley rats. The effects of GLT on the metabolic stability of AC were also investigated using rat liver microsome incubation systems. Results: The results indicated that the C_max increased from 36.84 ± 4.21 to 48.68 ± 6.35 ng/mL, and the AUC_(0-t) increased from 135.82 ± 21.05 to 77.28 ± 12.92 ng h/mL, and t_1/2 also increased from 2.62 ± 0.31 to 3.32 ± 0.57 h when GLT and AC were co-administered. The metabolic stability of AC was also increased (48.2 ± 6.7 vs. 36.7 ± 5.3 min) with the pre-treatment of GLT. Discussion: This study indicated that the main components in GLT could accelerate the metabolism of AC in rat liver microsomes and change the pharmacokinetic behaviours of AC. So these results showed that the herb-drug interaction between GLT and AC might occur, and the clinical efficacy could increase when they were co-administered. Therefore, the clinical dose of AC should be decreased when GLT and AC are co-administered.

Constructing a bilingual website with validated database for Herb and Western medicine interactions using Ginseng, Ginkgo and Dong Quai as examples

Background

Concerns have been raised regarding the efficacy and safety resulting from the potential interactions of herbs with Western medications due to the use of both herbs and Western medicine by the general public. Information obtained from the web must be critically evaluated prior to its use in making decisions.

Description

This study aimed to construct an herb-drug interaction (HDI) website (https://drug-herb-interaction.netlify.com) with a critically reviewed database. Node.js was used to store the database by running JavaScript. Vue.js is a front-end framework used for web interface development. A total of 135 sets of information related to the interactions of ginseng, ginkgo and dong quai with Western medicine from the literature identified in Medline were collected, followed by critical reviews to prepare nineteen items of information for each HDI monograph. A total of 80 sets of validated HDIs met all criteria and were further assessed at the individual reliability level (likely, possible, and unevaluable) and labeled with the “interaction” item. This query system of the website can be operated in both the Chinese and English languages to obtain all monographs on HDIs in the database, including bilingual interaction data. The database of HDI monographs can be updated by simply uploading a new version of the information Excel file. The designed “smart search” module, in addition to the “single search”, is convenient for requesting multiple searches. Among the “likely” interactions (n = 26), 50% show negative HDIs. Ten of these can increase the effect of the Western drug, and the others (n = 3) imply that the HDI can be beneficial.

Conclusions

The current study provides a website platform and 80 sets of validated bilingual HDIs involving ginseng, ginkgo and dong quai in an online database. A search of HDI monographs related to these three herbs can be performed with this bilingual, easy-to-use query website, which is feasible for professionals and the general public. The identified reliability level for each HDI may assist readers’ decisions regarding whether taking Western medications concomitant with one of three herbal medicinal foods is safe or whether caution is required due to potentially serious outcomes.

Influence of organic anion transporter 1/3 on the pharmacokinetics and renal excretion of ginkgolides and bilobalide

ETHNOPHARMACOLOGICAL RELEVANCE

The major terpene lactones of ginkgo biloba extract (GBE) include ginkgolide A, B, C and bilobalide are used for the protection of cardiovascular, cerebrovascular and neurodegenerative diseases. Terpene lactones are orally bioavailable and predominantly eliminated via the renal pathway. However, information on the transporters involved in the pharmacokinetics (PK) and renal excretion of terpene lactones is limited.

AIM OF THE STUDY

The objective of this study is to assess the role of OAT1/3 which are important transporters in the human kidney in the PK and renal excretion ginkgolide A, B, C and bilobalide.

MATERIALS AND METHODS

Uptake of ginkgolide A, B, C and bilobalide in Madin-Darby Canine Kidney (MDCK) and human embryonic kidney 293 (HEK293) cells overexpressing OAT1 or OAT3, respectively were studied. To verify the result from in vitro cell models, the studies on PK, kidney accumulation and urinary excretion of ginkgolide A, B, C and bilobalide were carried out in rats.

RESULTS

The result showed that ginkgolide A, B, C and bilobalide are low-affinity substrates of OAT1/3. Following co-administration with probenecid, a typical inhibitor of OAT1/3, the rat plasma concentrations of ginkgolide A, B, C and bilobalide increased significantly. AUC showed a significant increase in the probenecid-treated rats compared to control rats (893.48 vs. 1123.85, 314.91 vs. 505.74, and 2724.97 vs. 3096.40 μg/L*h for ginkgolide A, B and bilobalide, respectively), while the clearance of these compounds significantly decreased. The accumulation of ginkgolide A, B and bilobalide in the kidney of the probenecid-treated rats was reduced by 1.8, 2.4, and 1.5-fold, respectively; further reducing the cumulative urinary recovery of these compounds.

CONCLUSION

The findings indicated that ginkgolide A, B and bilobalide are excreted via OAT1/3-mediated transport in the kidney and OAT1/3 inhibitor significantly influence the PK ginkgolides and bilobalide.

In vitro Inhibitory Effects of Cynaroside on Human Liver Cytochrome P450 Enzymes

INTRODUCTION

Cynaroside is a biological component isolated from Lonicera japonica Thunb, and it possesses numerous pharmacological activities. However, whether cynaroside affects the activity of human liver cytochrome P450 (CYP) enzymes remains unclear. The purpose of this study was to investigate the effects of cynaroside on 8 major CYP isoforms in human liver microsomes (HLMs).

METHODS

In this study, the inhibitory effects of cynaroside on the 8 human liver CYP isoforms (i.e., 1A2, 3A4, 2A6, 2E1, 2D6, 2C9, 2C19, and 2C8) were investigated in vitro using HLMs.

RESULTS

The results showed that cynaroside inhibited the activity of CYP1A2, 3A4, and 2C9, with IC50 values of 21.74, 15.88, and 16.58 μmol/L, respectively, but that other CYP isoforms were not affected. Enzyme kinetic studies showed that cynaroside was not only a noncompetitive inhibitor of CYP3A4 but also a competitive inhibitor of CYP1A2 and 2C9, with Ki values of 7.33, 11.60, and 8.09 μmol/L, respectively. In addition, cynaroside is a time-dependent inhibitor for CYP3A4 with Kinact/KI value of 0.049/11.62 μmol/L-1min-1.

CONCLUSION

The in vitro studies of cynaroside with CYP isoforms indicate that cynaroside has the potential to cause pharmacokinetic drug interactions with other coadministered drugs metabolized by CYP1A2, 3A4, and 2C9. Further clinical studies are needed to evaluate the significance of this interaction.

Reviewing the mechanisms of natural product-drug interactions involving efflux transporters and metabolic enzymes

The World Health Organization (WHO) and other worldwide health agencies have recently taken initiatives to encourage the use of traditional medicine and/or complementary/alternative medicine in order to promote well-being and public health. In this way, one of the WHO's concerns is the safe use of these therapies. Phytotherapy is a strategy consisting of the use of medicinal plants (MP) and/or herbal medicinal products (HMP) for medicinal purposes. The use of phytotherapy concomitantly with drugs may cause interactions compromising the expected pharmacological action or generating toxic effects. These interactions are complex processes that may occur with multiple medications targeting different metabolic pathways, and involving different compounds present in MP and HMP. Thus, the aim of this review was to summarize the main MP- and HMP-drug interactions that involve specific transporters (P-glycoprotein and BCRP) and CYP450 enzymes (CYP3A4 and CYP2D6), which play relevant roles in the mechanisms of interactions. Firstly, multiple databases were used to search studies describing in vitro or in vivo MP and HMP-drug interactions and, after that, a systematic note-taking and appraisal of the literature was conducted. It was observed that several MP and HMP, metabolic pathways and transcription factors are involved in the transporters and enzymes expression or in the modulation of their activity having the potential to provide such interactions. Thus, the knowledge of MP- and HMP-drug interaction mechanisms could contribute to prevent harmful interactions and can ensure the safe use of these products to help the establishment of the therapeutic planning in order to certify the best treatment strategy to be used.

Influence of andrographolide on the pharmacokinetics of warfarin in rats

CONTEXT

Andrographolide and warfarin are often used together in clinics in China. However, the herb-drug interaction between andrographolide and warfarin is still unknown.

OBJECTIVE

This study investigates the herb-drug interaction between andrographolide and warfarin in vivo and in vitro.

MATERIALS AND METHODS

A sensitive and reliable LC-MS/MS method was developed for the determination of warfarin in male Sprague-Dawley rats plasma, and then the pharmacokinetics of orally administered warfarin (0.5 mg/kg) with or without andrographolide (30 mg/kg/day for 7 days) pretreatment was investigated. In addition, Sprague-Dawley rat liver microsomes incubation systems were used to support the in vivo pharmacokinetic data and investigate its potential mechanism.

RESULTS

The method validation results showed that a sensitive and reliable LC-MS/MS method was developed for the determination of warfarin in rat plasma samples. The pharmacokinetic results indicated that co-administration of andrographolide could increase the systemic exposure of warfarin significantly, including area under the curve (118.92 ± 18.08 vs. 60.58 ± 9.46 μg × h/mL), maximum plasma concentration (3.32 ± 0.41 vs. 2.35 ± 0.25 μg/mL) and t_1/2 (22.73 ± 3.28 vs. 14.27 ± 2.67 h). Additionally, the metabolic stability of warfarin increased from 23.5 ± 4.7 to 38.7 ± 6.1 min with the pretreatment of andrographolide, and the difference was significant (p < 0.05).

DISCUSSION AND CONCLUSION

In conclusion, andrographolide could increase the systemic exposure of warfarin in rats when andrographolide and warfarin were co-administered, and possibly by slowing down the metabolism of warfarin in rat liver by inhibiting the activity of CYP3A4 or CYP2C9.

Effects of Danshen tablets on pharmacokinetics of atorvastatin calcium in rats and its potential mechanism

CONTEXT

Danshen tablets (DST), an effective traditional Chinese multi-herbal formula, are often combined with atorvastatin calcium (AC) for treating coronary heart disease in the clinic.

OBJECTIVE

This study investigated the effects of DST on the pharmacokinetics of AC and the potential mechanism.

MATERIALS AND METHODS

The pharmacokinetics of AC (1 mg/kg) with or without pretreatment of DST (100 mg/kg) were investigated using LC-MS/MS. The effects of DST (50 μg/mL) on the metabolic stability of AC were also investigated using rat liver microsome incubation systems.

RESULTS

The results indicated that C_max (23.87 ± 4.27 vs. 38.94 ± 5.32 ng/mL), AUC_(0-t) (41.01 ± 11.32 vs. 77.28 ± 12.92 ng h/mL), and t_1/2 (1.91 ± 0.18 vs. 2.74 ± 0.23 h) decreased significantly (p < 0.05) when DST and AC were co-administered, which suggested that DST might influence the pharmacokinetic behavior of AC when they are co-administered. The metabolic stability (t_1/2) of AC was also decreased (25.7 ± 5.2 vs. 42.5 ± 6.1) with the pretreatment of DST.

DISCUSSION AND CONCLUSIONS

This study indicated that the main components in DST could accelerate the metabolism of AC in rat liver microsomes and change the pharmacokinetic behaviors of AC. So these results showed that the herb-drug interaction between DST and AC might occur when they were co-administered. Therefore, the clinical dose of AC should be adjusted when DST and AC are co-administered.

Eugenia jambolana extract reduces the systemic exposure of Sitagliptin and improves conditions associated with diabetes: A pharmacokinetic and a pharmacodynamic herb-drug interaction study

Eugenia jambolana (EJ) is an Indian traditional herb widely used for the treatment of diabetes mellitus. This herb is globally marketed as single or multi herb formulations. Many diabetes patients consume EJ extract oral hypoglycemic drugs together. This calls for a need to assess risks versus benefit of this co-administration.

In present investigation, pharmacodynamic and pharmacokinetic interactions of aqueous extract of EJ seeds at the dose of 400 mg/kg are studied with 10 mg/kg of oral hypoglycaemic drug sitagliptin (SITA) by co-administrating them for 28 days in streptozotocin (STZ) induced diabetic rats. The pharmacokinetic parameters of SITA were determined using HPLC-ESI-MS/MS and it was found that the combination treatment reduces the systemic exposure of SITA by showing 38.70% reduction in concentration maximum (Cmax) and 22.40% reduction in area under curve (AUC). Despite low levels of SITA, the combination demonstrated a significant reduction in blood glucose level when compared with individual drug and individual extract administered groups during pharmacodynamic study. In addition, the liver function, the kidney function and the lipid parameters were found to be significantly improved and beneficial effects were found with respect to food intake and water intake and urine output in case of combination treatment groups when compared with individual treatment groups. Histopathological examination of pancreatic tissue suggests its significant recovery of having normal acinus with better cell protection in combination treatment. In conclusion, the combination treatment demonstrated reduced systemic exposure of SITA without compromising on its antihyperglycemic activity and improvement in conditions associated with diabetes.

Effects of triptolide on pharmacokinetics of fenofibrate in rats and its potential mechanism

Triptolide and fenofibrate are often used together for the treatment of nephrotic syndrome in Chinese clinics. This study investigates the effects of triptolide on the pharmacokinetics of fenofibrate in rats and it potential mechanism. The pharmacokinetics of fenofibrate (20 mg/kg) with or without triptolide pretreatment (2 mg/kg/day for seven days) were investigated. Additionally, the inhibitory effects of triptolide on the metabolic stability of fenofibrate were investigated using rat liver microsome incubation systems. The results indicated that the C_max (35.34 ± 7.52 vs. 30.43 ± 6.45 μg/mL), t_1/2 (6.17 ± 1.15 vs. 4.90 ± 0.82 h) and AUC_(0-t) (468.12 ± 35.84 vs. 416.35 ± 32.68 mg h L^-1) of fenofibric acid decreased significantly (p < .05). The T_max of fenofibric acid increased significantly (p < .05) from 5.12 ± 0.36 to 6.07 ± 0.68 h. Additionally, the metabolic stability of fenofibrate was prolonged from 35.8 ± 6.2 to 48.6 ± 7.5 min (p < .05) with the pretreatment of triptolide. In conclusion, these results indicated that triptolide could affect the pharmacokinetics of fenofibric acid, possibly by inhibiting the metabolism of fenofibrate in rat liver when they were co-administered.

Bush mint (Hyptis suaveolens) and spreading hogweed (Boerhavia diffusa) medicinal plant extracts differentially affect activities of CYP1A2, CYP2D6 and CYP3A4 enzymes

ETHNO-PHARMACOLOGICAL RELEVANCE

Hyptis suaveolens (L) Poit and Boerhavia diffusa Linn are medicinal herbal plants commonly found in the tropics and sub-tropics. They are used to treat various conditions among them boils, dyslipidaemia, eczema, malaria, jaundice and gonorrhoea. Thus, the herbal medicinal extracts are now found as part of some commercial herbal formulations. There has not been adequate characterization of these medicinal herbs on their effects on drug metabolising enzymes.

AIM OF THE STUDY

To investigate the effects of extracts of Hyptis suaveolens (HS) and Boerhavia diffusa (BD) on activity of drug metabolising enzymes, CYP1A2, CYP2D6 and CYP3A4, as well predict their potential for herb-drug interaction. A secondary aim was to identify constituent compounds such as polyphenolics, in the crude extract preparations of Hyptis suaveolens and Boerhavia diffusa and measure them for activity.

MATERIALS AND METHODS

CYP450 inhibition assays using recombinant CYP450 (rCYP) and fluorescence screening employing individual isozymes (CYP1A2, CYP2D6 and CYP3A4) were used to determine reversible- and time-dependent inhibition (TDI) profiles of extracts of Hyptis suaveolens and Boerhavia diffusa. Inhibition kinetic parameters, K_i and K_inact were also estimated. UPLC-MS employing a Synapt G2 (ESI negative) coupled to a PDA detector was used to identify polyphenolic compounds in crude extracts of Hyptis suaveolens and Boerhavia diffusa.

RESULTS

The inhibitory potency of Hyptis suaveolens and Boerhavia diffusa extracts varied among the different enzymes, with CYP1A2 (3.68 ± 0.10µg/mL) being the least inhibited by HS compared to CYP2D6 (1.39 ± 0.01µg/mL) and CYP3A4 (2.36 ± 0.57µg/mL). BD was most potent on CYP3A4 (7.36 ± 0.94µg/mL) compared to both CYP2D6 (17.79 ± 1.02µg/mL) and CYP1A2 (9.48 ± 0.78µg/mL). Extracts of Hyptis suaveolens and Boerhavia diffusa exhibited TDIs on all CYPs. The most prominent phenolic candidates identified in both medicinal herbs using UPLC-MS analysis included caffeic acid, rutin, quercetin, citric acid, ferulic acid and gluconic acid. These phenolic compounds are thought to potentially give HS and BD their therapeutic effects and inhibitory characteristics affecting CYP450 activities. In vivo predictions showed the potential for HS and BD extracts to cause significant interactions if co-administered with other medications.

CONCLUSIONS

The study reveals that crude aqueous extracts of HS and BD potentially inhibit drug metabolising isozymes CYP1A2, CYP2D6 and CYP3A4 in a reversible and time-dependent manner. Thus care should be taken when these extracts are co-administered with drugs that are substrates of CYP1A2, CYP2D6 and CYP3A4.

Repeated administration of Sailuotong, a fixed combination of Panax ginseng, Ginkgo biloba, and Crocus sativus extracts for vascular dementia, alters CYP450 activities in rats

BACKGROUND

Sailuotong (SLT) is a standard Chinese preparation made from extracts of Panax ginseng (ginseng), Ginkgo biloba (ginkgo), and Crocus sativus (saffron). Preliminary clinical trials and animal experiments have demonstrated that SLT could improve cognition of vascular dementia (VD).

PURPOSE

To avoid incident drug-drug interaction which is easily encountered in patients of VD, the potential influence of SLT on main drug-metabolic cytochromes P450 enzymes (CYP450) was investigated.

METHOD

A "cocktail probes" approach was employed to evaluate the activities of CYP450. A rapid and selective analysis method was developed to examine 5 CYP probe drugs and their specific metabolites in plasma by using online SPE followed by a single LC-MS/MS run. After pretreatment for 2 weeks with SLT, ginseng, gingko, saffron or water (control), a cocktail solution containing caffeine, losartan, omeprazole, dextromethorphan and midazolam was given to rats orally. The plasma was obtained at different time intervals and then measured for the concentration of probes and their metabolites using developed SPE-LC-MS/MS method. Activity of five isozymes was estimated by comparing plasma pharmacokinetics of substrates and their metabolites (caffeine/paraxanthine for CYP1A2, losartan/E-3174 for CYP2C11, omeprazole/5-hydroxyl omeprazole for CYP2C6, dextromethorphan/dextrophan for CYP2D2 and midazolam/1-hydroxyl midazolam for CYP3A1/2) between control and drug treatment groups.

RESULT

Compared with control group, repeated administration of SLT induced CYP1A2 by enhancing AUC _paraxanthine / AUC _caffeine to144%. The influence is attributed to its herbal component of ginseng to a large extent. Meanwhile, metabolic ability towards losartan was significantly elevated in SLT and gingko group by 31% and 25% respectively, indicating weak induction of CYP2C11 in rats. The analysis on probes of omeprazole and dextromethorphan showed a lack of influence on CYP 2C6 and CYP2D2 in all treated groups. In terms of CYP3A1/2, SLT decreased AUC ratio of 1-hydroxyl midazolam to midazolam by 39% and extended the half-life of midazolam apparently. Besides, significantly decreased systematic exposure of midazolam suggested the inhibition on metabolism of CYP3A1/2 is likely secondary to the interaction on absorption at intestinal level. The inhibition of SLT on CYP3A was likely attributed to ginseng and gingko cooperatively.

CONCLUSION

Further observation on herb-drug interaction should be considered during clinical application of SLT.

Pregnancy, prescription medicines and the potential risk of herb-drug interactions: a cross-sectional survey

Background

Pregnant women are routinely prescribed medicines while self-medicating with herbal natural products to treat predominantly pregnancy related conditions. The aim of this study was to assess the potential for herb-drug interactions (HDIs) in pregnant women and to explore possible herb-drug interactions and their potential clinical significance.

Methods

A cross-sectional survey of women during early pregnancy or immediately postpartum in North-East Scotland. Outcome measures included; Prescription medicines use excluding vitamins and potential HDIs assessed using Natural Medicines Comprehensive Database.

Results

The survey was completed by 889 respondents (73% response rate). 45.3% (403) reported the use of at least one prescription medicine, excluding vitamins. Of those taking prescription medicines, 44.9% (181) also reported concurrent use of at least one HNP (Range 1–12). A total of 91 different prescription medicines were reported by respondents using HNPs. Of those taking prescription medicines, 44.9% (181) also reported concurrent use of at least one HNP (Range 1–12). Thirty-four herb-drug interactions were identified in 23 (12.7%) women with the potential to increase the risk of postpartum haemorrhage, alter maternal haemodynamics, and enhance maternal/fetal CNS depression.

Almost all were rated as moderate (93.9%), one as a potentially major (ginger and nifedipine) and only one minor (ondansetron and chamomile).

Conclusion

Almost half of pregnant women in this study were prescribed medicines excluding vitamins and minerals and almost half of these used HNPs. Potential moderate to severe HDIs were identified in an eighth of the study cohort. Healthcare professionals should be aware that the concurrent use of HNPs and prescription medicines during pregnancy is common and carries potential risks.

Evaluation of herb-drug interaction of a polyherbal Ayurvedic formulation through high throughput cytochrome P450 enzyme inhibition assay

ETHNOPHARMACOLOGICAL RELEVANCE

Arishtas are Ayurvedic formulation made with decoction of herbs. Arjunarishta formulation is being used in Ayurveda for cardio-protective activity. Ashwagandharishta formulation possesses antioxidant, anti-atherosclerotic and anti-stress properties. Ridayarishta, a novel empirical formulation was prepared using combination of selected ingredients from these two formulations to support healthy heart functions and to reduce stress.

AIM OF THE STUDY

Aim of the Study was to investigate herb-drug interaction (HDI) of Ridayarishta formulation through human hepatic cytochrome P450 (CYP450) enzyme inhibition assay.

MATERIALS AND METHODS

Ridayarishta formulation was phyto-chemically standardized against arjunolic acid, arjunetin, berberine, piperine, resveratrol and withaferin-A using high performance thin layer chromatography (HPTLC) analysis. The formulation was standardized with respect to ethanol by gas chromatographic (GC) analysis. HDI was evaluated with Ridayarishta formulation and amlodipine besilate, atenolol, atorvastatin, metformin, glipizide glimepiride cocktail using high throughput CYP450 enzyme inhibition assay; against CYP1A2, 2C19, 2D6 and 3A4 isozymes.

RESULTS

Contents of arjunolic acid, arjunetin, berberine, piperine, resveratrol and withaferin-A in Ridayarishta formulation were found to be 1.76±0.12, 1.51±0.09, 1.85±0.05, 3.2±0.12, 1.21±0.08, and 2.16±0.09ppm, respectively. Quantity of ethanol in Ridayarishta was found to be 7.95±0.023% (V/V). Ridayarishta showed significantly higher (P<0.001) IC₅₀ value against CYP1A2 (IC₅₀-13.80±1.96µg/mL), 2C19 (IC₅₀-14.343±2.28µg/mL), 2D6 (IC₅₀-0.897±0.28µg/mL) and 3A4 (IC₅₀-32.057±2.51µg/mL) compared to positive controls such as furafylline, tranylcypromine, quinidine and ketoconazole respectively. Cocktail of herbal formulation and cardio protective, antihypertensive, anti-diabetic drugs showed significantly (P<0.001and P<0.01) less or negligible HDI.

CONCLUSION

Ridayarishta formulation alone and cocktail with amlodipine besilate, atenolol, atorvastatin, metformin, glipizide, glimepiride had negligible or insignificant effect on CYP450 inhibition. It may be concluded that consumption of Ridayarishta along with selective cardio protective, antihypertensive and anti-diabetic conventional medicine is safe with negligible or without any significant CYP450 (CYP1A2, 2C19, 2D6 and 3A4) inhibition mediated HDI.

Isochlorogenic acid A affects P450 and UGT enzymes in vitro and in vivo

Isochlorogenic acid A (ICQA), which has anti-inflammatory, hepatoprotective, and antiviral properties, is commonly presented in fruits, vegetables, coffee, plant-based food products, and herbal medicines. These herbal medicines are usually used in combination with other medicines in the clinic. However, little is known about the regulatory effects of ICQA on drug-metabolizing enzymes and the herb-drug interactions. In the present study, we evaluated the inhibitory potentials of ICQA on CYP1A2, CYP2C9, CYP2C19, CYP3A4, CYP2D6, and CYP2E1 in vitro based on a cocktail approach. The P450 and UGT activities in mice treated with ICQA for a prolonged period were also determined. Our results demonstrated that ICQA exhibited a weak inhibitory effect on CYP2C9 in human liver microsomes with IC₅₀ being 57.25 μmol·L^-1 and Ki being 26.77 μmol·L^-1. In addition, ICQA inhibited UGT1A6 activity by 25%, in the mice treated with ICQA (i.p.) at 30 mg·kg^-1 for 14 d, compared with the control group. Moreover, ICQA showed no mechanism-based inhibition on CYP2C9 or UGT1A6. In conclusion, our results further confirm a safe use of ICQA in clinical practice.

Evaluation of the combination of Uvaria chamae (P. Beauv.) and amodiaquine in murine malaria

ETHNOPHARMACOLOGICAL RELEVANCE

The leaf and fruit of Uvaria chamae P. Beauv (Annonaceae) are used in antimalarial ethnomedical preparations. Therefore, they were investigated for antimalarial activities as well as possible herb-drug interaction with amodiaquine (AQ).

MATERIALS AND METHODS

The methanol extracts of the leaf (UCL) and fruit (UCF) were administered orally at 100-800mg/kg/day in mice infected with chloroquine (CQ)-sensitive Plasmodium berghei NK65 using the four-day, curative and prophylactic antimalarial test models. The UCL was further evaluated at 100-800mg/kg as twice-daily doses and combinations of UCL+AQ using the four-day test. Mice infected with CQ-resistant P. berghei ANKA were treated with UCL at 400mg/kg and AQ at 10mg/kg - [UCL400+AQ10]mg/kg - in the four-day and curative test models.

RESULT

At 800mg/kg/day, UCL, UCF gave chemosuppression of 42, 28% (four-day test), parasite clearance of 36.3, 49.5% on day 5 (curative test) and 64.3, 82.6% (prophylactic test), respectively. The twice-daily dose of UCL at 800mg/kg showed activity of 51.50% while the combination of [UCL200+AQ5]mg/kg exhibited chemosuppression of 91.66%, which was not significantly different (p>0.05) from AQ at 10mg/kg (85.41%). In the CQ-resistant P. berghei experiment, the combination gave a chemosuppression of 45.80%, significantly lower (p<0.05) than AQ (78.40%) while the parasite clearance was not significantly different from AQ (curative test).

CONCLUSION

The leaf extract showed moderate chemosuppressive activity. The lower-dose combination of the leaf extract and amodiaquine had better antimalarial activity in CQ-sensitive murine malaria. However, the tested combination had no beneficial antimalarial effect in CQ-resistant murine malaria.