Interaction of citrus juices with felodipine and nifedipine

Pharmacokinetic interactions of fruit juices with antihypertensive drugs in humans: A systematic review and meta-analysis

INTRODUCTION

Fruit juice-antihypertensive drug interactions can lead to subtherapeutic or supratherapeutic outcomes. This systematic review and meta-analysis assesses such interactions and their potential clinical relevance.

METHODS

PubMed, Scopus, and Science Direct databases were searched from their inception through June 2024. Eligible studies were those that investigated the effects of fruit juice on the pharmacokinetics of antihypertensive drugs. I2 was used to determine heterogeneity among studies, and a random effect model was employed for meta-analysis. This review adhered to PRISMA guidelines and was registered in PROSPERO (CRD42022340159).

RESULTS

Fifty-one studies were included. Most of them were open-label crossover trials. Grapefruit juice (GFJ), an inhibitor of organic-anion-transporting polypeptide (OATP) transporters and cytochrome P450 (CYP) 3A4, significantly decreased the AUC and Cmax of aliskiren and celiprolol by approximately 80-90 %. Conversely, the AUC and Cmax of calcium channel blockers decreased with variable degrees when co-administered with GFJ. Apple and orange juices have comparable effects on certain medications. Most studies had small sample sizes and were of moderate quality. Hemodynamic effects were not assessed in most studies; thus, the clinical significance of these interactions remains uncertain and should be further investigated.

CONCLUSION

Co-administration of fruit juice with antihypertensive drugs can result in an increase or decrease in drugs' bioavailability, depending on the drugs' metabolism route and the involvement of transporters. Though further studies are needed to confirm clinical relevance in hypertensive patients, it is advised to avoid co-consumption of fruit juice with drugs showing significant changes in pharmacokinetic parameters to prevent subtherapeutic or supratherapeutic effects.

Risk assessment of CYP3A induction by ginsenosides' metabolites from oral Panax notoginseng (Sanqi) extract

ETHNOPHARMACOLOGICAL RELEVANCE

In China, the integration of Chinese traditional medicine with Western medicine for the treatment of multifactorial diseases provides notable therapeutic benefits. Given this integration involving co-administration of herbal medicines and synthetic drugs, it is critical to evaluate the potential for associated drug interactions.

AIM OF THE STUDY

This investigation aimed to evaluate an oral extract of Panax notoginseng roots (Sanqi) for its potential to induce CYP3A activity, which may contribute to herb-drug interactions.

METHODS

Human microbiota-associated (HMA) rats were used to determine whether repeated oral administration of Sanqi extract induces CYP3A activity. Cryopreserved primary rat and human hepatocytes were used to evaluate the ability of ginsenoside metabolites and their combinations to induce rat Cyp3a and human CYP3A. Fecal samples from HMA rats repeatedly treated with oral Sanqi extract were analyzed for microbial deglycosylation activity on ppt-type ginsenosides. Quantitative real-time polymerase chain reaction was used to measure mRNA levels of rat Cyp3a1 and Cyp3a2, and human CYP3A4 and CYP3A5. Liquid chromatography/mass spectrometry was used to quantify ginsenosides and their metabolites in rat samples and in vitro study samples. 16S rRNA gene sequencing was used to analyze intestinal microbiota composition.

RESULTS

Repeated oral administration of Sanqi extract did not induce hepatic Cyp3a expression in rats. Neither ginsenoside metabolites nor their combinations induced rat Cyp3a or human CYP3A in vitro. Systemic exposure to oxidized metabolites of 20(S)-protopanaxtriol showed significant accumulation in HMA rats following repeated administration of Sanqi extract. This accumulation pattern mirrored previous findings in humans. The increased systemic exposure to the oxidized metabolites was likely due to enhanced microbial deglycosylation activity resulting from repeated oral administration of the extract.

CONCLUSIONS

Oral Sanqi extract exhibits a low propensity to induce CYP3A. This limited potential for drug interactions supports its safe use in cardiovascular therapies, particularly in polypharmacy settings.

Non-nutritive sweeteners in food-drug interactions: An overview of current evidence

Food-drug interactions occur when the presence of foods interferes with the absorption, distribution, metabolism, or excretion of pharmaceuticals. Specific compounds within foods, like certain phytochemicals from grapefruit, have been known to precipitate food-drug interactions for decades, leading to guidance from physicians and pharmacists about patients' dietary restrictions while taking certain drugs. Although approved by the Food and Drug Administration, high-intensity non-nutritive sweeteners (NNS) share qualities with drugs that suggest the potential for similar interactions. In this minireview, we have reviewed 5 of the most popular NNS, including saccharin, aspartame, acesulfame potassium, sucralose, and stevia, and detail their drug-like qualities, regulatory status, pharmacokinetics, and primary research articles containing evidence of NNS interacting with drug absorption, distribution, metabolism, and excretion. Although studies varied widely in concentration ranges for NNS, model systems, and methods, all NNS included in this review were found to have known interactions with mediators of absorption, distribution, metabolism, and excretion from studies conducted after their Food and Drug Administration approval or generally recognized as safe designation. We have highlighted essential gaps in the literature and recommend the scientific community actively research NNS as food additives that may interact with drugs. SIGNIFICANCE STATEMENT: Food-drug interactions are a growing concern in Western societies where polypharmacy and ultraprocessed foods and beverages are increasingly common. High-intensity non-nutritive sweeteners bear structural similarities to pharmaceuticals, and evidence suggests they interact with mediators of drug pharmacokinetics. This minireview highlights the interactions uncovered thus far and serves as a call to action for the scientific community to establish rigorous, consistent testing that will enable updated safety guidelines for consumers.

A review on phytochemicals as combating weapon for multidrug resistance in cancer

One can recognize multidrug resistance (MDR) and residue as a biggest difficulty in cancer specialist. Chemotherapy-resistant cancer may be successfully treated by combining MDR-reversing phytochemicals with anticancer drugs. Though, clinical application of phytochemicals either alone or in conjunction with chemotherapy is still in its early stages or requires more research to determine their safety and efficacy. In this review we highlighted topics related to MDR in cancer, including an introduction to subject, mechanism of action of efflux pump, specific proteins involved in drug resistance, altered drug targets, increased drug metabolism, and potential role of phytochemicals in overcoming drug resistance.

A 2OGD multi-gene cluster encompasses functional and tissue specificity that direct furanocoumarin and pyranocoumarin biosynthesis in citrus

Furanocoumarins (FCs) are plant defence compounds derived from the phenylpropanoid pathway via the coumarin umbelliferone that harbour some therapeutic benefits yet are the underlying cause of 'grapefruit-drug interactions' in humans. Most of the pathway genes have not been identified in citrus. We employed a genetic/Omics approach on citrus ancestral species and F1 populations of mandarin × grapefruit and mandarin × pummelo. Enzyme specificity was characterized by In vivo 2-oxoglutarate-dependent dioxygenase family (2OGD) activity assays. We identified a 2OGD multi-gene cluster involved in coumarin/FC/pyranocoumarin biosynthesis; Species lacking FCs in leaves/fruit were homozygous for a 655-base solo-LTR frame-disrupting insertion within one dual specificity C2'H/F6'H encoding 2OGD gene, demonstrating that integrity of this gene is fully correlated with the capacity to biosynthesize metabolites of the extended FC pathway in leaves/fruit. A second 2OGD is the prominent gene expressed in citrus roots, which contain a unique pattern of extended FC pathway metabolites, including the predominant pyranocoumarins. A third 2OGD gene encodes a single activity F6'H, which appears to be induced at the transcript level by citrus pathogens. The results provide insights into the genetic basis underlying the difference between citrus fruit FC producers (grapefruit and pummelo) and nonproducers (mandarin and orange) and provide a gene target to breed for FC-free varieties by marker-assisted breeding or genome editing.

Analysis of hemorrhagic drug-drug interactions between P-gp inhibitors and direct oral anticoagulants from the FDA Adverse Event Reporting System

BACKGROUND

Limited understanding exists regarding the hemorrhagic risk resulting from potential interactions between P-glycoprotein (P-gp) inhibitors and direct oral anticoagulants (DOACs). Utilizing the Food and Drug Administration Adverse Event Reporting System (FAERS) data, we analyzed hemorrhagic adverse events (AEs) linked with the co-administration of P-gp inhibitors and DOACs, aiming to offer guidance for their safe and rational use.

METHODS

Hemorrhagic events associated with P-gp inhibitors in combination with DOACs were scrutinized from the FAERS database. Hemorrhagic signals mining was performed by estimating the reported odds ratios (RORs), corroborated by additive and multiplicative models and a combination risk ratio (PRR) model.

RESULTS

Our analysis covered 4,417,195 cases, revealing 11,967 bleeding events associated with P-gp inhibitors. We observed a significantly higher risk of bleeding with the combination of apixaban and felodipine (ROR 118.84, 95% CI 78.12-180.79, additive model 0.545, multiplicative model 1.253, PRR 22.896 (2450.141)). Moreover, consistent associations were found in the co-administration analyzes of rivaroxaban with dronedarone and diltiazem, and apixaban with losartan, telmisartan, and simvastatin.

CONCLUSION

Our FAERS data analysis unveils varying degrees of bleeding risk associated with the co-administration of P-gp inhibitors and DOACs, underscoring the importance of vigilance about them in clinical practice.

Impact of Pomegranate Juice on the Pharmacokinetics of CYP3A4- and CYP2C9-Mediated Drugs Metabolism: A Preclinical and Clinical Review

The Punica granatum L. (pomegranate) fruit juice contains large amounts of polyphenols, mainly tannins such as ellagitannin, punicalagin, and punicalin, and flavonoids such as anthocyanins, flavan-3-ols, and flavonols. These constituents have high antioxidant, anti-inflammatory, anti-diabetic, anti-obesity, and anticancer activities. Because of these activities, many patients may consume pomegranate juice (PJ) with or without their doctor's knowledge. This may raise any significant medication errors or benefits because of food-drug interactions that modulate the drug's pharmacokinetics or pharmacodynamics. It has been shown that some drugs exhibited no interaction with pomegranate, such as theophylline. On the other hand, observational studies reported that PJ prolonged the pharmacodynamics of warfarin and sildenafil. Furthermore, since it has been shown that pomegranate constituents inhibit cytochrome P450 (CYP450) activities such as CYP3A4 and CYP2C9, PJ may affect intestinal and liver metabolism of CYP3A4 and CYP2C9-mediated drugs. This review summarizes the preclinical and clinical studies that investigated the impact of oral PJ administration on the pharmacokinetics of drugs that are metabolized by CYP3A4 and CYP2C9. Thus, it will serve as a future road map for researchers and policymakers in the fields of drug-herb, drug-food and drug-beverage interactions. Preclinical studies revealed that prolonged administration of PJ increased the absorption, and therefore the bioavailability, of buspirone, nitrendipine, metronidazole, saquinavir, and sildenafil via reducing the intestinal CYP3A4 and CYP2C9. On the other hand, clinical studies are limited to a single dose of PJ administration that needs to be protocoled with prolonged administration to observe a significant interaction.

Food effects on gastrointestinal physiology and drug absorption

Food ingestion affects the oral absorption of many drugs in humans. In this review article, we summarize the physiological factors in the gastrointestinal (GI) tract that affect the in vivo performance of orally administered solid dosage forms in fasted and fed states in humans. In particular, we discuss the effects of food ingestion on fluid characteristics (pH, bile concentration, and volume) in the stomach and small intestine, GI transit of water and dosage forms, and microbiota. Additionally, case examples of food effects on GI physiology and subsequent changes in oral drug absorption are provided. Furthermore, the effects of food, especially fruit juices (e.g., grapefruit, orange, apple) and green tea, on transporter-mediated permeation and enzyme-catalyzed metabolism of drugs in intestinal epithelial cells are also summarized comprehensively.

Drug-food Interactions in the Era of Molecular Big Data, Machine Intelligence, and Personalized Health

The drug-food interaction brings forth changes in the clinical effects of drugs. While favourable interactions bring positive clinical outcomes, unfavourable interactions may lead to toxicity. This article reviews the impact of food intake on drug-food interactions, the clinical effects of drugs, and the effect of drug-food in correlation with diet and precision medicine. Emerging areas in drug-food interactions are the food-genome interface (nutrigenomics) and nutrigenetics. Understanding the molecular basis of food ingredients, including genomic sequencing and pharmacological implications of food molecules, helps to reduce the impact of drug-food interactions. Various strategies are being leveraged to alleviate drug-food interactions; measures including patient engagement, digital health, approaches involving machine intelligence, and big data are a few of them. Furthermore, delineating the molecular communications across dietmicrobiome- drug-food-drug interactions in a pharmacomicrobiome framework may also play a vital role in personalized nutrition. Determining nutrient-gene interactions aids in making nutrition deeply personalized and helps mitigate unwanted drug-food interactions, chronic diseases, and adverse events from their onset. Translational bioinformatics approaches could play an essential role in the next generation of drug-food interaction research. In this landscape review, we discuss important tools, databases, and approaches along with key challenges and opportunities in drug-food interaction and its immediate impact on precision medicine.

Multi-compound and drug-combination pharmacokinetic research on Chinese herbal medicines

Traditional medicine has provided a basis for health care and disease treatment to Chinese people for millennia, and herbal medicines are regulated as drug products in China. Chinese herbal medicines have two features. They normally possess very complex chemical composition. This makes the identification of the constituents that are together responsible for the therapeutic action of an herbal medicine challenging, because how to select compounds from an herbal medicine for pharmacodynamic study has been a big hurdle in such identification efforts. To this end, a multi-compound pharmacokinetic approach was established to identify potentially important compounds (bioavailable at the action loci with significant exposure levels after dosing an herbal medicine) and to characterize their pharmacokinetics and disposition. Another feature of Chinese herbal medicines is their typical use as or in combination therapies. Coadministration of complex natural products and conventional synthetic drugs is prevalent worldwide, even though it remains very controversial. Natural product–drug interactions have raised wide concerns about reduced drug efficacy or safety. However, growing evidence shows that incorporating Chinese herbal medicines into synthetic drug-based therapies delivers benefits in the treatment of many multifactorial diseases. To address this issue, a drug-combination pharmacokinetic approach was established to assess drug–drug interaction potential of herbal medicines and degree of pharmacokinetic compatibility for multi-herb combination and herbal medicine–synthetic drug combination therapies. In this review we describe the methodology, techniques, requirements, and applications of multi-compound and drug-combination pharmacokinetic research on Chinese herbal medicines and to discuss further development for these two types of pharmacokinetic research.

Herb-drug Interactions in Neuropsychiatric Pharmacotherapy - A Review of Clinically Relevant Findings

The management of neuropsychiatric disorders relies heavily on pharmacotherapy. The use of herbal products as complimentary medicine, often concomitantly, is common among patients taking prescription neuropsychiatric drugs. Herb-drug interaction, a clinical consequence of this practice, may jeopardize the success of pharmacotherapy in neuropsychiatry. Besides the wellknown ability of phytochemicals to inhibit and/or induce drug-metabolizing enzymes and transport proteins, several phytoconstituents are capable of exerting pharmacological effects on the central nervous system. This study reviewed the relevant literature and identified 13 commonly used herbal products - celery, echinacea, ginkgo, ginseng, hydroxycut, kava, kratom, moringa, piperine, rhodiola, St. John's wort, terminalia/commiphora ayurvedic mixture and valerian - which have shown clinically relevant interactions with prescription drugs used in the management of neuropsychiatric disorders. The consequent pharmacokinetic and pharmacodynamic interactions with orthodox medications often result in deleterious clinical consequences. This underscores the importance of caution in herb-drug co-medication.

Role of Hesperidin and Fresh Orange juice in altering the bioavailability of Beta-Blocker, Metoprolol Tartrate. An invivo model

1. The aim of my study was to find the effect of co-administrating orange juice and hesperidin on the bioavailability of metoprolol tartrate in rabbits.2. Metoprolol tartrate (10mg/kg) was given orally to rabbits with hesperidin (10mg/Kg) and with orange juice (6ml/Kg) separately.3. The plasma concentrations of metoprolol tartrate was determined using Reverse Phase-High Performance Liquid Chromatography at 1.5, 1, 2, 4 and 6 hours and the pharmacokinetic parameters were studied.4. In comparison to the control group, the AUC of metoprolol tartrate was increased significantly by 68.32% with hesperidin while orange juice substantially reduced the AUC by 37.08% .However no significant change was observed in T_max K_el and Vd in both groups. The relative bioavailability of metoprolol tartrate with hesperidin was 168.3% as compared to orange juice i-e 62.9%.5. The present study revealed that the concurrent intake of hesperidin with metoprolol tartrate increased its bioavailability while orange juice administration suppressed its bioavailability. The change in bioavailability of metoprolol tartrate might be due to alterations in the activity of cytochrome P450 enzymes involved in the metabolism of metoprolol tartrate. However, the exact mechanism is still not known. These interactions may be of clinical significance.

Drug-Drug Interactions With Over-The-Counter Medicines: Mind the Unprescribed

BACKGROUND

This review provides a summary of the currently available clinical data on drug-drug interactions (DDIs) involving over-the-counter (OTC) medicines. It aims to educate and increase awareness among health care providers and to support decisions in daily practice.

METHODS

An extensive literature search was performed using bibliographic databases available through PubMed.gov. An initial structured search was performed using the keywords "drug-drug-interaction AND (over-the-counter OR OTC)," without further restrictions except for the language. The initial results were screened for all described DDIs involving OTC drugs, and further information was gathered specifically on these drugs using dedicated database searches and references found in the bibliography from the initial hits.

RESULTS

From more than 1200 initial hits (1972-June 2021), 408 relevant publications were screened for DDIs involving OTC drugs, leading to 2 major findings: first, certain types of drug regimens are more prone to DDIs or have more serious DDI-related consequences, such as antiretroviral, anti-infective, and oral anticancer therapies. Second, although most DDIs involve OTC drugs as the perpetrators, some prescription drugs (statins or phosphodiesterase-5 inhibitors) that currently have OTC status can be identified as the victims in DDIs. The following groups were identified to be frequently involved in DDIs: nonsteroidal anti-inflammatory drugs, food supplements, antacids, proton-pump inhibitors, H2 antihistamines, laxatives, antidiarrheal drugs, and herbal drugs.

CONCLUSIONS

The most significant finding was the lack of high-quality evidence for commonly acknowledged interactions. High-quality interaction studies involving different phenotypes in drug metabolism (cytochrome P450) and distribution (transporters) are urgently needed. This should include modern and critical drugs, such as oral anticancer medications and direct oral anticoagulants.

The Challenge and Importance of Integrating Drug-Nutrient-Genome Interactions in Personalized Cardiovascular Healthcare

Despite the rich armamentarium of available drugs against different forms of cardiovascular disease (CVD), major challenges persist in their safe and effective use. These include high rates of adverse drug reactions, increased heterogeneity in patient responses, suboptimal drug efficacy, and in some cases limited compliance. Dietary elements (including food, beverages, and supplements) can modulate drug absorption, distribution, metabolism, excretion, and action, with significant implications for drug efficacy and safety. Genetic variation can further modulate the response to diet, to a drug, and to the interaction of the two. These interactions represent a largely unexplored territory that holds considerable promise in the field of personalized medicine in CVD. Herein, we highlight examples of clinically relevant drug–nutrient–genome interactions, map the challenges faced to date, and discuss their future perspectives in personalized cardiovascular healthcare in light of the rapid technological advances.

Implication of metabolomics and transporter modulation based strategies to minimize multidrug resistance and enhance site-specific bioavailability: a needful consideration toward modern anticancer drug discovery

Induction of drug-metabolizing enzymes and efflux transporters (DMET) through activation of pregnane x receptor (PXR) is the primary factor involved in almost all bioavailability and drug resistance-related problems of anticancer drugs. PXR is a transcriptional regulator of many metabolizing enzymes and efflux transporters proteins like p-glycoprotein (p-gp), multidrug resistant protein 1 and 2 (MRP 1 and 2), and breast cancer resistant protein (BCRP), etc. Several anticancer drugs are potent activators of PXR receptors and can modulate the gene expression of DMET proteins. Involvement of anticancer drugs in transcriptional regulation of DMET can prompt increased metabolism and efflux of their own or other co-administered drugs, which leads to poor site-specific bioavailability and increased drug resistance. In this review, we have discussed several novel strategies to evade drug-induced PXR activation and p-gp efflux including assessment of PXR ligand and p-gp substrate at early stages of drug discovery. Additionally, we have critically discussed the chemical structure and drug delivery-based approaches to avoid PXR binding and inhibit the p-gp activity of the drugs at their target sites.

Inhibition of Cytochrome P450 Enzymes by Drugs-Molecular Basis and Practical Applications

Drug-drug interactions are a major cause of hospitalization and deaths related to drug use. A large fraction of these is due to inhibition of enzymes involved in drug metabolism and transport, particularly cytochrome P450 (P450) enzymes. Understanding basic mechanisms of enzyme inhibition is important, particularly in terms of reversibility and the use of the appropriate parameters. In addition to drug-drug interactions, issues have involved interactions of drugs with foods and natural products related to P450 enzymes. Predicting drug-drug interactions is a major effort in drug development in the pharmaceutical industry and regulatory agencies. With appropriate in vitro experiments, it is possible to stratify clinical drug-drug interaction studies. A better understanding of drug interactions and training of physicians and pharmacists has developed. Finally, some P450s have been the targets of drugs in some cancers and other disease states.

Alcohol-medication interactions: A systematic review and meta-analysis of placebo-controlled trials

Alcohol and other xenobiotics may limit the therapeutic effects of medications. We aimed at investigating alcohol-medication interactions (AMI) after the exclusion of confounding effects related to other xenobiotics. We performed a systematic review and meta-analysis of controlled studies comparing the effects induced by alcohol versus placebo on pharmacodynamic and/or pharmacokinetic parameters of approved medications. Certainty in the evidence of AMI was assessed when at least 3 independent studies and at least 200 participants were available. We included 107 articles (3097 participants): for diazepam, cannabis, opioids, and methylphenidate, we found significant AMI and enough data to assign the certainty of evidence. Alcohol consumption significantly increases the peak plasma concentration of diazepam (low certainty; almost 290 participants), cannabis (high certainty; almost 650 participants), opioids (low certainty; 560 participants), and methylphenidate (moderate certainty; 290 participants). For most medications, we found some AMI but not enough data to assign them the certainty grades; for some medications, we found no differences between alcohol and placebo in any outcomes evaluated. Our results add further evidence for interactions between alcohol and certain medications after the exclusion of confounding effects related to other xenobiotics. Physicians should advise patients who use these specific medications to avoid alcohol consumption. Further studies with appropriate control groups, enough female participants to investigate sex differences, and elderly population are needed to expand our knowledge in this field. Short phrases suitable for indexing terms.

Nanoparticulate Drug Delivery Strategies to Address Intestinal Cytochrome P450 CYP3A4 Metabolism towards Personalized Medicine

Drug dosing in clinical practice, which determines optimal efficacy, toxicity or ineffectiveness, is critical to patients' outcomes. However, many orally administered therapeutic drugs are susceptible to biotransformation by a group of important oxidative enzymes, known as cytochrome P450s (CYPs). In particular, CYP3A4 is a low specificity isoenzyme of the CYPs family, which contributes to the metabolism of approximately 50% of all marketed drugs. Induction or inhibition of CYP3A4 activity results in the varied oral bioavailability and unwanted drug-drug, drug-food, and drug-herb interactions. This review explores the need for addressing intestinal CYP3A4 metabolism and investigates the opportunities to incorporate lipid-based oral drug delivery to enable precise dosing. A variety of lipid- and lipid-polymer hybrid-nanoparticles are highlighted to improve drug bioavailability. These drug carriers are designed to target different intestinal regions, including (1) local saturation or inhibition of CYP3A4 activity at duodenum and proximal jejunum; (2) CYP3A4 bypass via lymphatic absorption; (3) pH-responsive drug release or vitamin-B12 targeted cellular uptake in the distal intestine. Exploitation of lipidic nanosystems not only revives drugs removed from clinical practice due to serious drug-drug interactions, but also provide alternative approaches to reduce pharmacokinetic variability.

The association between citrus consumption and melanoma risk in the UK Biobank

BACKGROUND

Melanoma incidence has been dramatically increasing worldwide. Psoralen, a known photocarcinogen, is naturally abundant in citrus products, leading to the hypothesis that high citrus consumption may increase melanoma risk.

OBJECTIVES

To investigate the association between total citrus consumption and melanoma risk, and the association between individual citrus products and melanoma risk, and to test for interactions between total citrus intake and established melanoma risk factors.

METHODS

Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the association between citrus consumption and melanoma risk among 1592 cases and 197 372 controls from the UK Biobank cohort. Citrus consumption data were collected via five rounds of 24-h recall questionnaires. International Classification of Diseases codes were used to determine melanoma outcome.

RESULTS

After adjusting for potential confounders, participants in the highest category of total citrus intake (> 2 servings per day) had a significantly increased risk of melanoma (OR 1·63, 95% CI 1·24-2·12) relative to those with no consumption. For individual citrus products, participants with the most orange and orange juice consumption (> 1 serving per day) had a significantly increased melanoma risk relative to those with no consumption (OR 1·79, 95% CI 1·07-2·78 and OR 1·54, 95% CI 1·10-2·10, respectively). Fair- or very fair-skinned participants with high citrus consumption had an even greater melanoma risk (OR 1·75, 95% CI 1·31-2·29).

CONCLUSIONS

High citrus consumption was associated with an increased risk of melanoma in a large, prospective, population-based cohort. Further validation of these findings could lead to improved melanoma prevention strategies.

Determination of benchmark doses for linear furanocoumarin consumption associated with inhibition of cytochrome P450 1A2 isoenzyme activity in healthy human adults

Millions of individuals globally consume traditional herbal medicines (THMs), which contain abundant amounts of linear furanocoumarins. Linear furanocoumarins (i.e., 8-methoxypsoralen, 5-methoxypsoralen, and isopimpinellin) are inhibitors of cytochrome P450 (CYP) isoenzymes including 1A2, a major enzyme involved in drug metabolism and carcinogen bioactivation. Despite the high consumption of furanocoumarin-containing THMs, no studies have measured the furanocoumarin consumption level that triggers an inhibition to CYP1A2 activity in humans. The first objective was to verify if the potencies of the three furanocoumarins are additive towards the inhibition of CYP1A2 activity in vitro using concentration-addition and whole-mixture chemical-mixture-assessment models. A second objective was to determine the benchmark dose (BMD) with the mixtures of furanocoumarin oral doses, expressed as 8-MOP equivalents, and to assess the in vivo CYP1A2 activity, expressed as inhibition percentages. The in vitro results indicated that the three furanocoumarin inhibitory potencies were additive in the THM extracts, validating the use of the concentration-addition model in total furanocoumarin dose-equivalent calculations. Using the USEPA BMD software, the BMD was 18.9 μg 8-MOP equivalent/kg body weight. This information is crucial for furanocoumarin-related health-assessment studies and the regulation of THMs. Further studies should be performed for the remaining major metabolic enzymes to complete the safety profile of furanocoumarin-containing THMs and to provide accurate warning labelling.

Phytochemicals reverse P-glycoprotein mediated multidrug resistance via signal transduction pathways

P-glycoprotein, encoded by ATP-binding cassette transporters B1 gene (ABCB1), renders multidrug resistance (MDR) during cancer chemotherapy. Several synthetic small molecule inhibitors affect P-glycoprotein (P-gp) transport function in MDR tumor cells. However, inhibition of P-gp transport function adversely accumulates chemotherapeutic drugs in non-target normal tissues. Moreover, most small-molecule P-gp inhibitors failed in the clinical trials due to the low therapeutic window at the maximum tolerated dose. Therefore, downregulation of ABCB1-gene expression (P-gp) in tumor tissues seems to be a novel approach rather than inhibiting its transport function for the reversal of multidrug resistance (MDR). Several plant-derived phytochemicals modulate various signal transduction pathways and inhibit translocation of transcription factors, thereby reverses P-gp mediated MDR in tumor cells. Therefore, phytochemicals may be considered an alternative to synthetic small molecule P-gp inhibitors for the reversal of MDR in cancer cells. This review discussed the role of natural phytochemicals that modulate ABCB1 expression through various signal transduction pathways in MDR cancer cells. Therefore, modulating the cell signaling pathways by phytochemicals might play crucial roles in modulating ABCB1 gene expression and the reversal of MDR.

Uptake Pathway of Apple-derived Nanoparticle by Intestinal Cells to Deliver its Cargo

PURPOSE

Food-derived nanoparticles exert cytoprotective effects on intestinal cells by delivering their cargo, which includes macromolecules such as microRNAs and proteins, as well as low-molecular weight compounds. We previously reported that apple-derived nanoparticles (APNPs) downregulate the expression of human intestinal transporter OATP2B1/SLCO2B1 mRNA. To verify the involvement of the cargo of APNPs in affecting the expression of transporters, we characterized the uptake mechanism of APNPs in intestinal cells.

METHODS

The uptake of fluorescent PKH26-labeled APNPs (PKH-APNPs) into Caco-2, LS180, and HT-29MTX cells was evaluated by confocal microscopy and flow cytometry.

RESULTS

The uptake of PKH-APNPs was prevented in the presence of clathrin-dependent endocytosis inhibitors, chlorpromazine and Pitstop2. Furthermore, PKH-APNPs were incorporated by the HT29-MTX cells, despite the disturbance of the mucus layer. Additionally, the decrease in SLCO2B1 mRNA by APNPs was reversed by Pitstop 2 in Caco-2 cells, indicating that APNPs decrease SLCO2B1 by being incorporated via clathrin-dependent endocytosis.

CONCLUSIONS

We demonstrated that clathrin-dependent endocytosis was mainly involved in the uptake of APNPs by intestinal cells, and that the cargo in the APNPs downregulate the mRNA expression of SLCO2B1. Therefore, APNPs could be a useful tool to deliver large molecules such as microRNAs to intestinal cells.

Drug-drug interaction (DDI) with direct oral anticoagulant (DOAC) in patients with cancer

Cancer-associated thrombosis (CAT) is the second leading cause of death in cancer patients after tumor progression. The treatment of CAT is challenging because of a high risk of VTE recurrence, a high risk of bleeding, common presence of comorbidities, poly-medication, and potential drug-drug interactions (DDI). Since 2018, direct oral anticoagulants (DOACs) represent a promising therapeutic alternative and have been recently included into the 2019 update of the International Initiative on Thrombosis and Cancer (ITAC-CME) clinical practice guidelines for management of CAT. However, pharmacokinetic studies suggest that concomitant treatment with P-gp or CYP3A4 inhibitors will result in an increased exposure to rivaroxaban and apixaban, but the clinical relevance of these studies is unknown. In addition, there is an important inter-individual variability in drug absorption, distribution, metabolism and elimination, even more in cancer patients. Overall, the risk of pharmacokinetic DDI should be estimated based on several individual (patient age, renal and liver function, number of comedications) and diseases-related factors, including inflammation, sarcopenia, and low body weight. In this context, DDI with clinical implications could be expected with anti-neoplastic agents or supportive care treatments, especially with drugs known to be moderate or strong inhibitors/inducers of CYP3A4 and P-gp. Consequently, in the presence of potential DDIs through CYP3A4, and/or P-gp, LMWHs remain the first-line anticoagulant of choice for the long-term treatment of CAT. Multidisciplinary consultation meetings and therapeutic patient education should be emphasized in the complex management of CAT.

Outgoing and potential trends of composition, health benefits, juice production and waste management of the multi-faceted Grapefruit Citrus Χ paradisi: A comprehensive review for maximizing its value

Grapefruit (GF) Citrus Χ paradisi Macfad (F. Rutaceae) is one of the major citrus fruits that encompass a myriad of bioactive chemicals and most unique among citrus fruits. Nevertheless, no study has yet to assess comprehensively its multitudinous constituents, health benefits, and valuable waste products. Hereto, the present review provides an updated comprehensive review on the different aspects of GF, its juice production, waste valorization, enhancement of its byproducts quality, and compared to other citrus fruits. Grapefruit uniqueness among other citrus fruits stands from its unique taste, flavor, and underlying complex chemical composition. Despite limonene abundance in peel oil and grapefruit juice (GFJ) aroma, nootkatone and sulfur compounds are the key determinants of its flavor, whereas flavanones contribute to its bitter taste and in conjunction with limonoids. Different postharvest treatments and juice processing are reviewed and in context to its influence on final product quality and or biological effects. Flavanones, furanocoumarins, and limonoids appear as the most prominent in GF drug interactions affecting its metabolism and or excretion. Valorization of GF peel is overviewed for its utilization as biosrobent, its oil in aromatherapy, limonene as antimicrobial or in cosmetics, fruit pectin for bioethanol production, or as biosorbent, and peel phenolics biotransformation. The present review capitalizes on all of the aforementioned aspects in GF and further explore novel aspects of its juice quality presenting the full potential of this valued multi-faceted citrus fruit.

[Quantitative Analysis of Gastrointestinal Physiology for Better Prediction of Oral Drug Absorption and Interaction]

Although oral drugs account for 80% of the world drug market, many difficulties arise in their development. The drug absorption profile after oral administration may be influenced by multiple factors, including dosing conditions and physiological state of the gastrointestinal (GI) tract. Variability in GI fluid volume may influence the absorption characteristics. Indeed, the contributions of passive diffusion, transporters, and metabolic enzymes depend on GI drug concentration, which is influenced by changes in GI fluid volume. However, this important variable has been neglected in many prediction methods for oral drug absorption and drug interactions, and for convenience it is often assumed that the GI water volume is fixed at a constant value. Major global regulatory agencies such as the U.S. Food and Drug Administration (FDA), European Medicines Agency (EMA), and Japanese Pharmaceuticals and Medical Devices Agency (PMDA) recommend using a constant fluid volume of 250 mL (the fluid volume of a glass of water) to estimate the theoretical GI concentration of drugs after oral administration. However, the actual volume of water in the GI tract is both time- and site-dependent as a result of water intake, absorption, secretion, and GI transit. This review article summarizes our data showing that luminal water volume is influenced by the osmolality of the applied solution, and illustrates how this effect may contribute to changes in GI drug concentration, resulting in altered drug absorption.

Interactions between antiretroviral therapy and complementary and alternative medicine: a narrative review

BACKGROUND

The use of complementary and alternative medicine including herbal medicine (phytotherapy), vitamins, minerals and food supplements is frequent among people living with HIV/AIDS (PLWHAs) who take antiretroviral (ARV) drugs, but is often not known by their prescribing physicians. Some drug-supplement combinations may result in clinically meaningful interactions.

AIMS

In this literature review, we aimed to investigate the evidence for complementary and alternative medicine interactions with ARVs.

SOURCES

A bibliographic search of all in vitro, human studies and case reports of the PubMed database was performed to assess the risk of interactions between complementary and alternative self-medication products and ARVs. The 'HIV drug interaction' (https://www.hiv-druginteractions.org) and 'Natural medicines comprehensive database' (https://naturalmedicines.therapeuticresearch.com) interaction checkers were also analysed.

CONTENT

St John's wort, some forms of garlic, grapefruit and red rice yeast are known to have significant interaction and thus should not be co-administered, or should be used with caution with certain ARV classes. Data on other plant-based supplements come from in vitro studies or very small size in vivo studies and are thus insufficient to conclude the real in vivo impact in case of concomitant administration with ARVs. Some polyvalent minerals such as calcium, magnesium, and iron salts can reduce the absorption of integrase inhibitors by chelation. Potential interactions with vitamin C and quercetin with some ARVs should be noted and efficacy and tolerance of the treatment should be monitored.

IMPLICATIONS

This review shows the importance of screening all PLWHAs for complementary and alternative medicine use to prevent treatment failure or adverse effects related to an interaction with ARVs. Further human studies are warranted to describe the clinical significance of in vitro interactions between numerous complementary and alternative medicine and ARVs.

Synthesis of Spin-Labelled Bergamottin: A Potent CYP3A4 Inhibitor with Antiproliferative Activity

Bergamottin (BM, 1), a component of grapefruit juice, acts as an inhibitor of some isoforms of the cytochrome P450 (CYP) enzyme, particularly CYP3A4. Herein, a new bergamottin containing a nitroxide moiety (SL-bergamottin, SL-BM, 10) was synthesized; chemically characterized, evaluated as a potential inhibitor of the CYP2C19, CYP3A4, and CYP2C9 enzymes; and compared to BM and known inhibitors such as ketoconazole (KET) (3A4), warfarin (WAR) (2C9), and ticlopidine (TIC) (2C19). The antitumor activity of the new SL-bergamottin was also investigated. Among the compounds studied, BM showed the strongest inhibition of the CYP2C9 and 2C19 enzymes. SL-BM is a more potent inhibitor of CYP3A4 than the parent compound; this finding was also supported by docking studies, suggesting that the binding positions of BM and SL-BM to the active site of CYP3A4 are very similar, but that SL-BM had a better ∆G_bind value than that of BM. The nitroxide moiety markedly increased the antitumor activity of BM toward HeLa cells and marginally increased its toxicity toward a normal cell line. In conclusion, modification of the geranyl sidechain of BM can result in new CYP3A4 enzyme inhibitors with strong antitumor effects.

Herbal Interaction With Chemotherapeutic Drugs-A Focus on Clinically Significant Findings

One of the most consequential risks associated with the concomitant use of herbal products and chemotherapeutic agents is herb-drug interactions. The risk is higher in patients with chronic conditions taking multiple medications. Herb-drug interaction is particularly undesirable in cancer management because of the precipitous dose-effect relationship and toxicity of chemotherapeutic agents. The most common mechanism of herb-drug interaction is the herbal-mediated inhibition and/or induction of drug-metabolizing enzymes (DME) and/or transport proteins leading to the alteration in the pharmacokinetic disposition of the victim drug. Most mechanistic research has focused on laboratory-based studies, determining the effects of herbal products on DMEs and extrapolating findings to predict clinical relevance; however, not all DME/transporter protein inhibition/induction results in clinical herb-drug interaction. This study reviews relevant literature and identified six herbal products namely echinacea, garlic, ginseng, grapefruit juice, milk thistle, and St John's wort, which have shown interactions with chemotherapeutic agents in humans. This focus on clinically significant herb-drug interaction, should be of interest to the public including practitioners, researchers, and consumers of cancer chemotherapy.

Structural Perspectives of the CYP3A Family and Their Small Molecule Modulators in Drug Metabolism

Cytochrome P450 enzymes function to catalyze a wide range of reactions, many of which are critically important for drug response. Members of the human cytochrome P450 3A (CYP3A) family are particularly important in drug clearance, and they collectively metabolize more than half of all currently prescribed medications. The ability of these enzymes to bind a large and structurally diverse set of compounds increases the chances of their modulating or facilitating drug metabolism in unfavorable ways. Emerging evidence suggests that individual enzymes in the CYP3A family play discrete and important roles in catalysis and disease progression. Here we review the similarities and differences among CYP3A enzymes with regard to substrate recognition, metabolism, modulation by small molecules, and biological consequence, highlighting some of those with clinical significance. We also present structural perspectives to further characterize the basis of these comparisons.

Pharmacokinetic parameters of ifosfamide in mouse pre-administered with grapefruit juice or naringin

Grapefruit juice (GFJ) and naringin when consumed previously or together with medications may alter their bioavailavility and consequently the clinical effect. Ifosfamide (IF) is an antitumoral agent prescribed against various types of cancer. Nevertheless, there is no information regarding its interaction with the ingestion of GFJ or naringin. The aims of the present report were validating a method for the quantitation of IF in the plasma of mouse, and determine if mice pretreated with GFJ or naringin may modify the IF pharmacokinetics. Our HPLC results to quantify IF showed adequate intra and inter-day precision (RSD < 15%) and accuracy (RE < 15%) indicating reliability. Also, the administration of GFJ or naringin increased Cmax of IF 22.9% and 17.8%, respectively, and decreased Tmax of IF 19.2 and 53.8%, respectively. The concentration of IF was higher when GFJ (71.35 ± 3.5 µg/mL) was administered with respect to that obtained in the combination naringin with IF (64.12 ± µg/mL); however, the time required to reach such concentration was significantly lower when naringin was administered (p < 0.5). We concluded that pre-administering GFJ and naringin to mice increased the Tmax and decreased the Cmax of IF.

Transporter-Mediated Drug-Drug Interactions and Their Significance

Drug transporters are considered to be determinants of drug disposition and effects/toxicities by affecting the absorption, distribution, and excretion of drugs. Drug transporters are generally divided into solute carrier (SLC) family and ATP binding cassette (ABC) family. Widely studied ABC family transporters include P-glycoprotein (P-GP), breast cancer resistance protein (BCRP), and multidrug resistance proteins (MRPs). SLC family transporters related to drug transport mainly include organic anion-transporting polypeptides (OATPs), organic anion transporters (OATs), organic cation transporters (OCTs), organic cation/carnitine transporters (OCTNs), peptide transporters (PEPTs), and multidrug/toxin extrusions (MATEs). These transporters are often expressed in tissues related to drug disposition, such as the small intestine, liver, and kidney, implicating intestinal absorption of drugs, uptake of drugs into hepatocytes, and renal/bile excretion of drugs. Most of therapeutic drugs are their substrates or inhibitors. When they are comedicated, serious drug-drug interactions (DDIs) may occur due to alterations in intestinal absorption, hepatic uptake, or renal/bile secretion of drugs, leading to enhancement of their activities or toxicities or therapeutic failure. This chapter will illustrate transporter-mediated DDIs (including food drug interaction) in human and their clinical significances.

Intravenous formulation of Panax notoginseng root extract: human pharmacokinetics of ginsenosides and potential for perpetrating drug interactions

XueShuanTong, a lyophilized extract of Panax notoginseng roots (Sanqi) for intravenous administration, is extensively used as add-on therapy in the treatment of ischemic heart and cerebrovascular diseases and comprises therapeutically active ginsenosides. Potential for XueShuanTong-drug interactions was determined; the investigation focused on cytochrome P450 (CYP)3A induction and organic anion-transporting polypeptide (OATP)1B inhibition. Ginsenosides considerably bioavailable for drug interactions were identified by dosing XueShuanTong in human subjects and their interaction-related pharmacokinetics were determined. The CYP3A induction potential was determined by repeatedly dosing XueShuanTong for 15 days in human subjects and by treating cryopreserved human hepatocytes with circulating ginsenosides; midazolam served as a probe substrate. Joint inhibition of OATP1B by XueShuanTong ginsenosides was assessed in vitro, and the data were processed using the Chou-Talalay method. Samples were analyzed by liquid chromatography/mass spectrometry. Ginsenosides Rb₁, Rd, and Rg₁ and notoginsenoside R₁ were the major circulating XueShuanTong compounds; their interaction-related pharmacokinetics comprised compound dose-dependent levels of systemic exposure and, for ginsenosides Rb₁ and Rd, long terminal half-lives (32‒57 and 58‒307 h, respectively) and low unbound fractions in plasma (0.8%‒2.9% and 0.4%‒3.0%, respectively). Dosing XueShuanTong did not induce CYP3A. Based on the pharmacokinetics and inhibitory potency of the ginsenosides, XueShuanTong was predicted to have high potential for OATP1B3-mediated drug interactions (attributed chiefly to ginsenoside Rb₁) suggesting the need for further model-based determination of the interaction potential for XueShuanTong and, if necessary, a clinical drug interaction study. Increased awareness of ginsenosides' pharmacokinetics and XueShuanTong-drug interaction potential will help ensure the safe use of XueShuanTong and coadministered synthetic drugs.

Bioavailability of the diterpenoid 14-deoxy-11,12-didehydroandrographolide in rats and up-regulation of hepatic drug-metabolizing enzyme and drug transporter expression

BACKGROUND

14-Deoxy-11,12-didehydroandrographolide (deAND) is the second most abundant diterpenoid in Andrographis paniculata (Burm. f.) Nees, a traditional medicine used in Asia. To date, the biological activity of deAND has not been clearly investigated.

PURPOSE

In this study, we intended to examine the modulatory effect of deAND on hepatic drug metabolism as well as its bioavailability.

STUDY DESIGN

deAND prepared from A. paniculata was orally given to Sprague-Dawley rats and changes in plasma deNAD were determined by HPLC-MS. Modulation of deAND on drug-metabolizing enzyme and drug transporter expression as well as the possible mechanism involved was examined in primary rat hepatocytes.

RESULTS

After a single oral administration of 50 mg/kg deAND to rats, the maximum plasma concentration (C_max), time to reach the C_max, area under the curve (AUC_0-24h), mean retention time, and half-life (t_1/2) of deAND were 2.65 ± 0.68 μg/ml, 0.29 ± 0.15 h, 6.30 ± 1.66 μg/ml•h, 5.55 ± 2.52 h, and 3.56 ± 1.05 h, respectively. The oral bioavailability was 3.42%. In primary rat hepatocytes treated with up to 10 μM deAND, a dose-dependent increase was noted in the expression of cytochrome P450 (CYP) 1A1/2, CYP2C6, and CYP3A1/2; UDP-glucuronosyltransferase (UGT) 1A1, NAD(P)H:quinone oxidoreductase (NQO1), π form of GSH S-transferase (GSTP), multidrug resistance-associated protein 2, p-glycoprotein, and organic anion transporter protein 2B1. Immunoblotting assay and EMSA revealed that deAND increases the nuclear translocation and DNA binding activity of aryl hydrocarbon receptor (AhR), pregnane X receptor (PXR), and nuclear factor erythroid-derived 2-related factor 2 (Nrf2). Knockdown of AhR and Nrf2 expression abolished deAND induction of CYP isozymes and UGT1A1, NQO1, and GSTP expression, respectively.

CONCLUSION

These results indicate that deAND quickly passes through enterocytes in rats and effectively up-regulates hepatic drug-metabolizing enzyme and drug transporter expression in an AhR-, PXR-, and Nrf2-dependent manner.

Effect of Osmolality on the Pharmacokinetic Interaction between Apple Juice and Atenolol in Rats

A recent clinical study reported that the ingestion of apple juice (AJ) markedly reduced the plasma concentration of atenolol; however, our in vitro study showed that atenolol may not be a substrate of organic anion transporting polypeptide 2B1 (OATP2B1), so this AJ-atenolol interaction cannot be explained by inhibition of OATP2B1. On the other hand, we more recently showed that the solution osmolality influences gastrointestinal (GI) water volume, and this may indirectly affect intestinal drug absorption. In this study, we examined whether the osmolality dependence of water dynamics can account for AJ-atenolol interactions by evaluating the GI water volume and the atenolol aborption in the presence of AJ in rats. Water absorption was highest in purified water, followed by saline and isosmotic mannitol solution, and the lowest in AJ, confirming that water absorption is indeed osmolality-dependent. Interestingly, AJ showed apparent water secretion into the intestinal lumen. The intestinal concentration of FD-4, a nonpermeable compound, after administration in AJ was lower than the initial concentration, whereas that in purified water was greater than the initial concentration. Further, the fraction of atenolol absorbed in intestine was significantly lower in AJ or hyperosmotic mannitol solution (adjusted to the osmolality of AJ) than after administration in purified water. Comparable results were observed in an in vivo pharmacokinetic study in rats. Our results indicate that orally administered AJ has a capacity to modulate luminal water volume depending on the osmolality, and this effect may result in significant AJ-atenolol interactions.

Understanding the relevance of herb-drug interaction studies with special focus on interplays: a prerequisite for integrative medicine

Integrative medicine refers to the blending of conventional and evidence-based complementary medicines and therapies with the aim of using the most appropriate of either or both modalities for ultimate patient benefits. One of the major hurdles for the same is the chances of potential herb–drug interactions (HDIs). These HDIs could be beneficial or harmful, or even fatal; therefore, a thorough understanding of the eventualities of HDIs is essential so that a successful integration of the modern and complementary alternative systems of medicine could be achieved. Here, we summarize all the important points related to HDIs, including types, tools/methods for study, and prediction of the HDIs, along with a special focus on interplays between drug metabolizing enzymes and transporters. In addition, this article covers future perspective, with a focus on background endogenous players of interplays and approaches to predict the drug–disease–herb interactions so as to fetch the desired effects of these interactions.

Drug Bioavailability Enhancing Agents of Natural Origin (Bioenhancers) that Modulate Drug Membrane Permeation and Pre-Systemic Metabolism

Many new chemical entities are discovered with high therapeutic potential, however, many of these compounds exhibit unfavorable pharmacokinetic properties due to poor solubility and/or poor membrane permeation characteristics. The latter is mainly due to the lipid-like barrier imposed by epithelial mucosal layers, which have to be crossed by drug molecules in order to exert a therapeutic effect. Another barrier is the pre-systemic metabolic degradation of drug molecules, mainly by cytochrome P450 enzymes located in the intestinal enterocytes and liver hepatocytes. Although the nasal, buccal and pulmonary routes of administration avoid the first-pass effect, they are still dependent on absorption of drug molecules across the mucosal surfaces to achieve systemic drug delivery. Bioenhancers (drug absorption enhancers of natural origin) have been identified that can increase the quantity of unchanged drug that appears in the systemic blood circulation by means of modulating membrane permeation and/or pre-systemic metabolism. The aim of this paper is to provide an overview of natural bioenhancers and their main mechanisms of action for the nasal, buccal, pulmonary and oral routes of drug administration. Poorly bioavailable drugs such as large, hydrophilic therapeutics are often administered by injections. Bioenhancers may potentially be used to benefit patients by making systemic delivery of these poorly bioavailable drugs possible via alternative routes of administration (i.e., oral, nasal, buccal or pulmonary routes of administration) and may also reduce dosages of small molecular drugs and thereby reduce treatment costs.

Inhibitory Effect of Japanese Traditional Kampo Formula Frequently Prescribed in Gynecological Clinics on CYP3A4

Recently, the use of herbal medicines has become popular, and information on drug interactions between herbal medicines and chemical drugs is needed in clinics. In Japan, the number of patients taking Japanese traditional Kampo medicines has been increasing, and the proper drug information about herb-drug interaction is highly demanded. The most established herb-drug interaction is the case of grapefruit juice (GFJ) via the inhibition on CYP3A4 expressed in the small intestine. In the present study, we compared the inhibitory titer on CYP3A4 between the target Kampo products and GFJ used as positive control. We evaluated the inhibitory effects of GFJ and three extracts of Kampo formulas frequently used in gynecological clinics on CYP3A4 in vitro and calculated the related titer of one-time dosage of Kampo formulas to GFJ in order to predict its effect on clinics. Although the extracts of these three Kampo formulas and the most of crude drug components in the formulas exhibited the inhibitory effects on CYP3A4 in some levels, the possibilities of tokishakuyakusan and keishibukuryogan to cause drug interaction can be quite low; however, it is possible that the excessive dosage of kamishoyosan may cause drug interaction with the substrate of CYP3A4 in clinics.

Beneficial Pharmacokinetic Drug Interactions: A Tool to Improve the Bioavailability of Poorly Permeable Drugs

Simultaneous oral intake of herbs, supplements, foods and drugs with other drug(s) may result in pharmacokinetic or pharmacodynamic interactions with the latter. Although these interactions are often associated with unwanted effects such as adverse events or inefficacy, they can also produce effects that are potentially beneficial to the patient. Beneficial pharmacokinetic interactions include the improvement of the bioavailability of a drug (i.e., by enhancing absorption and/or inhibiting metabolism) or prolongation of a drug's plasma level within its therapeutic window (i.e., by decreasing excretion), whereas beneficial pharmacodynamic interactions include additive or synergistic effects. Mechanisms by which pharmacokinetic interactions can cause beneficial effects include enhancement of membrane permeation (e.g., structural changes in the epithelial cell membranes or opening of tight junctions), modulation of carrier proteins (e.g., inhibition of efflux transporters and stimulation of uptake transporters) and inhibition of metabolic enzymes. In the current review, selected pharmacokinetic interactions between drugs and various compounds from different sources including food, herb, dietary supplements and selected drugs are discussed. These interactions may be exploited in the future to the benefit of the patient, for example, by delivering drugs that are poorly bioavailable in therapeutic levels via alternative routes of administration than parenteral injection.

Determination of citrus juice coumarins, furanocoumarins and methoxylated flavones using solid phase extraction and HPLC with photodiode array and fluorescence detection

A synergistic combination of analytical techniques was developed for the simultaneous determination of the three most biologically active chemical families in citrus juices: methoxylated flavones, coumarins, and furanocoumarins. No rapid methodology has been available to determine them together. A solid phase extraction concentrated these groups and a ternary reverse phase HPLC gradient completely resolved them from other juice components. Two coumarins, isomeranzin and osthole, were identified in a sweet orange (C. sinensis) cultivar, Changyecheng, for the first time. Pummelo juice was characterized by coumarin and furanocoumarin epoxides such as meranzin and epoxybergamottin. No epoxides were observed in the more acidic juices. Added furanocoumarin epoxides hydrolyzed rapidly in the most acidic juices. The ratios of the UV peak areas at 320 nm to the fluorescence emission peaks as well as the ratio of fluorescence emission peaks at 450-400 nm could be used to identify chromatographic peaks.

Integration of botanicals in contemporary medicine: road blocks, checkpoints and go-ahead signals

The use of botanicals for maintaining good health and preventing diseases is undisputed. The claimed health benefits of natural health products and herbal medicines are based on traditional claims, positive results obtained in preclinical studies and early phase clinical trials that are not backed by safety and efficacy evidences approved by regulatory agencies. Although, the popularity of botanicals is growing, health care practitioners of modern medicine seldom recommend their use because of ill equipped database of their safety and potency. This review discusses problems that preclude botanicals from integrating into the mainstream contemporary therapeutics and cues that provide impetus for their realisation.

Interactions between crude drug extracts used in Japanese traditional Kampo medicines and organic anion-transporting polypeptide 2B1

ETHNOPHARMACOLOGICAL RELEVANCE

The use of herbal medicines has become popular worldwide, and the information on drug interactions between herbal medicines and chemical drugs is needed.

AIM OF THE STUDY

We screened the inhibitory effects of crude drugs used in Kampo medicines used in Japan on organic anion-transporting polypeptide (OATP) 2B1 to predict potential interactions between Kampo medicines and chemical drugs used together.

MATERIALS AND METHODS

We chose 98 kinds of crude drugs frequently used as ingredients of Kampo formulations in Japan and prepared their boiling water extracts. We then screened their inhibitory effects on OATP2B1 by measuring the uptake of estrone 3-sulphate (E3S) by HEK293 cells stably expressing OATP2B1.

RESULTS

At the concentration of 100µg/ml, the extracts prepared from 12 kinds of crude drugs, Scuteralliae Radix, Arecae Semen, Aurantii Fructus Immaturus, Perillae Herba, Panacis Japonici Rhizoma, Moutan Cortex, Polygalae Radix, Rhei Rhizoma, Cannabis Fructus, Chrysanthemi Flos, Eriobotryae Folium, and Querci Cortex, suppressed the function of OATP2B1 by less than 20%. The extract of bofutsushosan, a representative Kampo formulation, inhibited OATP2B1 function with sufficient levels to suppress absorption of OATP2B1 substrates in clinics. We further evaluated the inhibitory effects of several ingredients containing Rhei Rhizoma, Perillae Herba, and Moutan Cortex on OATP2B1.

CONCLUSIONS

Because of crude drugs used in Kampo medicines might suppress absorption of OATP2B1 substrates, these results may contribute to the safe and effective use of Kampo medicine in clinics. A list of abbreviations: EC, (-)-epicatechin; ECG, epicatechin gallate; EGC, epigallocatechin; EGCG, Epigallocatechin gallate; FBS, fetal bovine serum; grapefruit juice; HEK293, Human embryonic kidney; IC_50, The half inhibitory concentration; OATP, organic anion-transporting polypeptide; β-PGG, penta-O-galloyl-β-D-glucose; t.i.d, 3 times a day.

Potentiating and synergistic effect of grapefruit juice on the antioxidant and anti-inflammatory activity of aripiprazole against hydrogen peroxide induced oxidative stress in mice

BACKGROUND

Dependence on antipsycotic drugs like aripriprazole (ARI) is increasing at alarming rate, hence, this study was undertaken to support the hypothesis that supplementation of Citrus paradisi (Grapefruit) juice having high concentration of polyphenols might potentiate and synergize the therapeutic effect of ARI, by increasing its bioavailability and inherent antioxidant potential. These benefits together might decrease the daily dosage of the ARI and thus alleviate the possible side effects of drug.

METHODS

In this study the antioxidant and anti-inflammatory potential of ARI alone and in combination with GFJ was evaluated for hydrogen peroxide (H₂O₂) induced oxidative stress in mice. Seventy mice (4 weeks old), were randomly divided into seven groups. Group I: Control; Group II: H₂O₂ treated; Group III; ARI treated; Group IV GFJ treated; Group V: GFJ and H₂O₂ treated; Group VI; ARI and H₂O₂ treated; Group VII; ARI, GFJ and H₂O₂ treated. Serum levels of alanine aminotransferase (ALT), blood urea nitrogen (BUN), creatinine kinase (CK), creatinine and total protein were measured. Furthermore, pro-inflammatory cytokines Interleukin (IL)-1α, IL-2, IL-10 and tumor necrosis factor-α (TNF-α) concentrations were also measured.

RESULTS

The mice group that was treated with ARI, GFJ or combination of the two showed significant improvement in the H₂O₂ altered parameters with the combination group showing more significant improvement than the ARI and GFJ alone groups indicating a synergistic and potentiating effect of the antioxidant and anti-inflammatory potential of GFJ on ARI.

CONCLUSION

Supplementing GFJ to ARI might increase an anti-oxidative potential of ARI due to inherent antioxidant and anti-inflammatory activity of GFJ and thus could alleviate the possible dosage dependent side effects of ARI.

Phytotherapeutics: The Emerging Role of Intestinal and Hepatocellular Transporters in Drug Interactions with Botanical Supplements

In herbalism, botanical supplements are commonly believed to be safe remedies, however, botanical supplements and dietary ingredients interact with transport and metabolic processes, affecting drug disposition. Although a large number of studies have described that botanical supplements interfere with drug metabolism, the mode of their interaction with drug transport processes is not well described. Such interactions may result in serious undesired effects and changed drug efficacy, therefore, some studies on interaction between botanical supplement ingredients and drug transporters such as P-gp and OATPs are described here, suggesting that the interaction between botanical supplements and the drug transporters is clinically significant.

Coffee inhibition of CYP3A4 in vitro was not translated to a grapefruit-like pharmacokinetic interaction clinically

Grapefruit can augment oral medication bioavailability through irreversible (mechanism-based) inhibition of intestinal CYP3A4. Supplementary data from our recent coffee-drug interaction clinical study showed some subjects had higher area under the plasma drug concentration - time curve (AUC) and plasma peak drug concentration (Cmax) of the CYP3A4 probe felodipine compared to aqueous control. It was hypothesized that coffee might interact like grapefruit in responsive individuals. Beans from six geographical locations were consistently brewed into coffee that was separated chromatographically to a methanolic fraction for in vitro inhibition testing of CYP3A4 metabolism of felodipine at 1% coffee strength. The effect of simultaneous incubation and 10-min preincubation with coffee fractions determined whether coffee had direct and mechanism-based inhibitory activity. A subsequent five-way randomized balanced controlled crossover clinical study evaluated the clinical pharmacokinetic interaction with single-dose felodipine. Grapefruit juice, water, or three of the in vitro tested coffees were ingested at 300 mL alone 1 h before and then with felodipine. In vitro, all six coffees decreased felodipine metabolism for both simultaneous and preincubation exposure compared to corresponding control. Five coffees demonstrated mechanism-based inhibition. Grapefruit increased felodipine AUC0-8 (25 vs. 13 ng.h/mL, P < 0.001) and Cmax (5.8 vs. 2.7 ng/mL, P < 0.001) and decreased dehydrofelodipine/felodipine AUC0-8 ratio (0.84 vs. 1.29, P < 0.001), while the three coffees caused no change in these parameters compared to water. Despite high in vitro potency of CYP3A4 inhibition, the coffees did not cause a clinical pharmacokinetic interaction possibly from insufficient amount of inhibitor(s) in coffee reaching intestinal CYP3A4 during the absorption phase of felodipine. The results of this study highlight the need for follow-up clinical testing when in vitro results indicate the possibility of an interaction.