Potential risks resulting from fruit/vegetable-drug interactions: effects on drug-metabolizing enzymes and drug transporters

Glabridin plays dual action to intensify anti-metastatic potential of paclitaxel via impeding CYP2C8 in liver and CYP2J2/EETs in tumor of an orthotopic mouse model of breast cancer

In spite of unprecedented advances in modern cancer therapy, there is still a dearth of targeted therapy to circumvent triple-negative breast cancer (TNBC). Paclitaxel is the front-line therapy against TNBC, but the main constraints of its treatment are dose-related adverse effects and emerging chemoresistance. In this context, glabridin (phytoconstituent from Glycyrrhiza glabra) is reported to hit multiple signalling pathways at the in-vitro level, but hardly any information is known at the in-vivo level. We aimed here to elucidate glabridin potential with an underlying mechanism in combination with a low dose of paclitaxel using a highly aggressive mouse mammary carcinoma model. Glabridin potentiated the anti-metastatic efficacy of paclitaxel by substantially curtailing tumor burden and diminishing lung nodule formation. Moreover, glabridin remarkably attenuated epithelial-mesenchymal transition (EMT) traits of hostile cancer cells via up-regulating (E-cadherin & occludin) and down-regulating (Vimentin & Zeb1) vital EMT markers. Besides, glabridin amplified apoptotic induction effect of paclitaxel in tumor tissue by declining or elevating pro-apoptotic (Procaspase-9 or Cleaved Caspase-9 & Bax) and reducing anti-apoptotic (Bcl-2) markers. Additionally, concomitant treatment of glabridin and paclitaxel predominantly lessened CYP2J2 expression with marked lowering of epoxyeicosatrienoic acid (EET)'s levels in tumor tissue to reinforce the anti-tumor impact. Simultaneous administration of glabridin with paclitaxel notably enhanced plasma exposure and delayed clearance of paclitaxel, which was mainly arbitrated by CYP2C8-mediated slowdown of paclitaxel metabolism in the liver. The fact of intense CYP2C8 inhibitory action of glabridin was also ascertained using human liver microsomes. Concisely, glabridin plays a dual role in boosting anti-metastatic activity by augmenting paclitaxel exposure via CYP2C8 inhibition-mediated delaying paclitaxel metabolism and limiting tumorigenesis via CYP2J2 inhibition-mediated restricting EETs level. Considering the safety, reported protective efficacy, and the current study results of boosted anti-metastatic effects, further investigations are warranted as a promising neoadjuvant therapy for crux paclitaxel chemoresistance and cancer recurrence.

Effect of Betanin, the Major Pigment of Red Beetroot (Beta vulgaris L.), on the Activity of Recombinant Human Cytochrome P450 Enzymes

Most of the currently available drugs are derived from natural sources, but they are used only after extensive chemical modifications to improve their safety and efficacy. Natural products are used in health supplements and cosmetic preparations and have been used as auxiliary drugs or alternative medicines. When used in combination with conventional drugs, these herbal products are known to alter their pharmacokinetics and pharmacodynamics, reducing their therapeutic effects. Moreover, herb-drug interactions (HDIs) may have serious side effects, which is one of the major concerns in health practice. It is postulated that HDIs affect the pathways regulating cytochrome P450 enzymes (CYPs). Betanin, the chief pigment of red beetroot (Beta vulgaris L.), has various types of pharmacological activity, such as anti-inflammatory, antioxidant, and anticancer effects. However, the potential risk of HDIs for betanin has not yet been studied. Thus, we aimed to predict more specific HDIs by evaluating the effects of betanin on CYPs (CYP1A2, CYP2B6, CYP2C9, CYP2C19, CYP2D6, and CYP3A4), the major phase I metabolic enzymes, using fluorescence-/luminescence-based assays. Our results showed that betanin inhibited CYP3A4 activity in a dose-dependent manner (IC50 = 20.97 µΜ). Moreover, betanin acted as a competitive inhibitor of CYP3A4, as confirmed by evaluating Lineweaver-Burk plots (Ki value = 19.48 µΜ). However, no significant inhibitory effects were observed on other CYPs. Furthermore, betanin had no significant effect on CYP1A2, CYP2B6, or CYP2C9 induction in HepG2 cells. In conclusion, betanin acted as a competitive inhibitor of CYP3A4, and thus it should be used cautiously with other drugs that require metabolic enzymes as substrates. Additional in vivo studies and clinical trials are needed to further elucidate the HDIs of betanin.

Possible Side Effects of Polyphenols and Their Interactions with Medicines

Polyphenols are an important component of plant-derived food with a wide spectrum of beneficial effects on human health. For many years, they have aroused great interest, especially due to their antioxidant properties, which are used in the prevention and treatment of many diseases. Unfortunately, as with any chemical substance, depending on the conditions, dose, and interactions with the environment, it is possible for polyphenols to also exert harmful effects. This review presents a comprehensive current state of the knowledge on the negative impact of polyphenols on human health, describing the possible side effects of polyphenol intake, especially in the form of supplements. The review begins with a brief overview of the physiological role of polyphenols and their potential use in disease prevention, followed by the harmful effects of polyphenols which are exerted in particular situations. The individual chapters discuss the consequences of polyphenols’ ability to block iron uptake, which in some subpopulations can be harmful, as well as the possible inhibition of digestive enzymes, inhibition of intestinal microbiota, interactions of polyphenolic compounds with drugs, and impact on hormonal balance. Finally, the prooxidative activity of polyphenols as well as their mutagenic, carcinogenic, and genotoxic effects are presented. According to the authors, there is a need to raise public awareness about the possible side effects of polyphenols supplementation, especially in the case of vulnerable subpopulations.

Formulation and characterization of liposomes containing drug absorption enhancers for optimized anti-HIV and antimalarial drug delivery

Most of the current clinically used anti-HIV and antimalarial drugs have low bioavailability, either due to poor solubility and permeability, rapid clearance from anatomical reservoirs and poor retention at their site of action (e.g. due to the p-glycoprotein efflux system), and extreme first-pass metabolism (e.g. by the cytochrome P450 enzymes). Hence, new approaches such as the incorporation of drug absorption enhancers (DAEs) (also referred to as bioenhancers) into dosage forms, and exploration of nanocarriers such as liposomes as novel dosage forms, are needed and may provide a viable means that could improve the bioavailability of both anti-HIV and antimalarial drugs. Liposomes loaded with efavirenz or mefloquine in combination with drug absorption enhancers, as well as placebo dosage forms, were prepared using a thin-lipid film hydration technique and characterized for their particle size and zeta potentials, entrapment efficiency, in vitro drug release, and in vitro drug permeability. Liposomes were further investigated for their biocompatibility (safety) using H-4-II-E liver cells in vitro. Drug-loaded liposomes prepared using l-α-phospatidylcholine, dioleoyl (DOPC) and cholesterol (CHOL) (1:1 mol/mol) as well as liposomes made of 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), CHOL, and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) (4:6:26 mol/mol/mol) exhibited the best results in terms of their entrapment efficiency, particle size, zeta potential, in vitro drug release, and permeability. DSPC:CHOL:DPPC liposomes released EFV-based formulations better than DPPC:CHOL liposomes for immediate release behaviour. DOPC:CHOL liposomes produced a controlled release and more drug was released in the presence of DAEs for both EFV (0.4-fold higher) and MQ-based (sevenfold higher) formulations in the first 2 h. However, these liposomes were less biocompatible (< 50% cell viability) with liver cells. DOPC:CHOL and DSPC:CHOL:DPPC liposomes could provide a useful nano-formulation platform, which could ensure drug loading, followed by sustained release of both anti-HIV and antimalaria drugs.

A Scoping Review of the Skeletal Effects of Naringenin

BACKGROUND

Osteoporosis is caused by the deterioration of bone density and microstructure, resulting in increased fracture risk. It transpires due to an imbalanced skeletal remodelling process favouring bone resorption. Various natural compounds can positively influence the skeletal remodelling process, of which naringenin is a candidate. Naringenin is an anti-inflammatory and antioxidant compound found in citrus fruits and grapefruit. This systematic review aims to present an overview of the available evidence on the skeletal protective effects of naringenin.

METHOD

A systematic literature search was conducted using the PubMed and Scopus databases in August 2022. Original research articles using cells, animals, or humans to investigate the bone protective effects of naringenin were included.

RESULTS

Sixteen eligible articles were included in this review. The existing evidence suggested that naringenin enhanced osteoblastogenesis and bone formation through BMP-2/p38MAPK/Runx2/Osx, SDF-1/CXCR4, and PI3K/Akt/c-Fos/c-Jun/AP-1 signalling pathways. Naringenin also inhibited osteoclastogenesis and bone resorption by inhibiting inflammation and the RANKL pathway.

CONCLUSIONS

Naringenin enhances bone formation while suppressing bone resorption, thus achieving its skeletal protective effects. It could be incorporated into the diet through fruit intake or supplements to prevent bone loss.

Bioactivity assessment of natural compounds using machine learning models trained on target similarity between drugs

Natural compounds constitute a rich resource of potential small molecule therapeutics. While experimental access to this resource is limited due to its vast diversity and difficulties in systematic purification, computational assessment of structural similarity with known therapeutic molecules offers a scalable approach. Here, we assessed functional similarity between natural compounds and approved drugs by combining multiple chemical similarity metrics and physicochemical properties using a machine-learning approach. We computed pairwise similarities between 1410 drugs for training classification models and used the drugs shared protein targets as class labels. The best performing models were random forest which gave an average area under the ROC of 0.9, Matthews correlation coefficient of 0.35, and F1 score of 0.33, suggesting that it captured the structure-activity relation well. The models were then used to predict protein targets of circa 11k natural compounds by comparing them with the drugs. This revealed therapeutic potential of several natural compounds, including those with support from previously published sources as well as those hitherto unexplored. We experimentally validated one of the predicted pair’s activities, viz., Cox-1 inhibition by 5-methoxysalicylic acid, a molecule commonly found in tea, herbs and spices. In contrast, another natural compound, 4-isopropylbenzoic acid, with the highest similarity score when considering most weighted similarity metric but not picked by our models, did not inhibit Cox-1. Our results demonstrate the utility of a machine-learning approach combining multiple chemical features for uncovering protein binding potential of natural compounds.

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.

Effect of nutritional status on acetaminophen pharmacokinetic profile

Short-term fasting increases acetaminophen exposure in healthy subjects, whereas no effect was observed after a high-fat diet. These findings suggest the necessity of considering nutritional status when assessing the risk of acetaminophen-induced toxicity. Further role of nutrition status on pharmacokinetic profile of acetaminophen (APAP) at toxic doses are not available. Our study aims to compare the effects of nutrition status on kinetic profile of APAP in 3 different dietary conditions like - Normal diet (ND), Low protein diet (LPD) and High fat diet (HFD) groups. To investigate the pharmacokinetic profile of APAP at toxic dose, 3 groups of animals were separated after weaning and for the next 15 weeks they were fed with their respective diets (ND, LPD and HFD). Animals were dosed with APAP (300 mg/kg p.o) and blood sampling was done at different time intervals. Plasma samples were analyzed using HPLC method. Data analysis was done by Non-compartment analysis using Phoenix WinNonlin 8.3 software. LPD group show higher values of C _max, T _max, T _1/2, and AUC _0-4, AUC _0-x values compared to ND and HFD groups. Our study compared APAP pharmacokinetic profile at toxic dose in three different diet regimes.

Green sweet potato leaves increase Nrf2-mediated antioxidant activity and facilitate benzo[a]pyrene metabolism in the liver by increasing phase II detoxifying enzyme activities in rats

Green and purple SPL consumption may enhance the Nrf2-mediated hepatic antioxidant activity and modulate xenobiotic-metabolizing enzymes and transporters via different mechanisms.

Determination of effective concentrations of drug absorption enhancers using in vitro and ex vivo models

BACKGROUND

Achievement of an effective concentration of the pharmaceutically active ingredient in the blood and/or at the target site is an important aspect in the formulation of drugs and therefore needs to be quantified. Any concentration above therapeutic levels can cause toxic effects whereas low concentrations can be sub-therapeutic. This paper investigated different concentrations of selected commercially sourced analytical-grade pure chemicals as potential drug absorption enhancers in vitro and ex vivo to determine the lowest effective concentrations for optimizing drug absorption in oral dosage forms.

METHODS

Recombinant cytochrome (CYP) 3A4 enzyme and recombinant p-glycoprotein membrane models were utilized for the investigation of in vitro inhibitory effects of drug absorption enhancers. Promega (2015) protocols were adopted for both assays. The everted porcine intestinal ex vivo model was employed for assessing effects of the drug absorption enhancers on the absorption of propranolol.

RESULTS

The lowest effective CYP3A4 inhibitory concentrations were observed for curcumin (75µM and 100 µM), quercetin (75 and 100 µM) and glycyrrhizic acid (50 µM) while the most effective p-glycoprotein (P-gp) inhibition concentrations were curcumin (10, 15, 25, 50, 75 and 100 µM), sinomenine (50, 75, and 100 µM), quercetin (75 and 100 µM) and naringin (50 µM). Additive effects were observed between combinations of quercetin (75 µM) and curcumin (100 µM); quercetin (75 µM) and curcumin (75 µM); quercetin (75 µM) and curcumin (50 µM), and quercetin (75 µM) with curcumin (10 µM), which increased the basal ex vivo absorption of propranolol from 1.24 ± 0.03 µg/mL to 5.19 ± 0.12 µg/mL, 4.17 ± 0.05 µg/mL, 3.86 ± 0.10 µg/mL, and 4.07± 0.05 µg/mL respectively, after 2 hours.

CONCLUSION

Incorporation of the drug absorption enhancers (e.g., curcumin and quercetin), at specific concentrations, in dosage forms could improve the bioavailability of the BCS Class III and IV drugs that are substrates of CYP3A4 and p-glycoprotein.

In vitro anticoagulant activity of selected medicinal plants: potential interactions with warfarin and development of new anticoagulants

OBJECTIVES

Warfarin is the most widely used anticoagulant in the world, but it has several limitations including its narrow therapeutic range, need for dose adjustment and high potential for interactions. The simultaneous use of other drugs or even medicinal plants and certain foods could interfere with its therapeutic activity. In this context, this study aims to investigate the in vitro anticoagulant potential and phytochemical constitution of 17 plants selected from a previous clinical cross-sectional study (2014), that investigated the habits of plant utilization among patients taking warfarin.

METHODS

Ethanol extracts and essential oils were evaluated, in vitro, as to their effect in the prothrombin time (PT) and activated partial thromboplastin time (aPTT) tests. Four species that presented aPTT >50 s were selected for phytochemical evaluation.

RESULTS

Thirteen of the 17 plants selected demonstrated a significant anticoagulant effect in at least one of the evaluated parameters. Citrus sinensis (PT=14.75 and aPTT=53.15), Mentha crispa (aPTT=51.25), Mikania laevigata (PT=14.90 and aPTT=52.10), and Nasturtium officinale (aPTT=50.55) showed greater anticoagulant potential compared to normal plasma pool (PT=12.25 and aPTT=37.73). Chemical profiles of these four species were obtained, and certain compounds were identified: rosmarinic acid from M. crispa and isoorientin from N. officinale.

CONCLUSIONS

Thus, the results of this study could be a useful indicator for clinical practice towards the possibility of interaction between these plants and anticoagulants, although further clinical research is needed taking into consideration the limitations of in vitro studies. These findings also suggest that further research into the action of these plants could be of real clinical value in identifying potential alternative anticoagulant therapies.

The in vitro toxicity of nitrile and epithionitrile derivatives of glucosinolates from swedes (Brassica napus) in human and bovine liver cells

AIM

To investigate the direct in vitro toxicity in human and bovine liver cells, and inhibition of activity of ATP-binding cassette transporter G2 (ABCG2) and cytochrome P450 3A4 (CYP3A4) by five nitrile and epithionitrile derivatives from swede (Brassica napus).

METHODS

The following compounds were investigated: 1-cyano-2-hydroxy-3-butene (CHB, epithionitrile derivative of progoitrin), 1-cyano-2-hydroxy-3,4-epithiobutane (epithionitrile derivative of progoitrin), 3-butenenitrile (nitrile from sinigrin), 4-pentenenitrile (nitrile from gluconapin), and 5-hexenenitrile (nitrile from glucobrassicanapin). Direct cytotoxicity was assessed by incubating the compounds (at 100 mM, 200 mM, 2 M) with human (HepG2) hepatocellular carcinoma cells or bovine primary hepatocytes for 24 hours. Cell viability was then assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cytotoxicity in Hep2G cells was also assessed after incubation for 72 hours at sub-chronic concentrations (1, 2.5, 5, 10, 15, 20 µM) and for combinations of compounds (20 µM). The ability of compounds to inhibit activity of the ABCG2 transporter and the CYP3A4 enzyme were assessed using human ABCG2 vesicles and demethylation of erythromycin by rat liver microsomes, respectively.

RESULTS

No reduction of cell viability compared to control assays was observed when the tested compounds were incubated with Hep2G cells or bovine liver cells at concentrations up to 2 mM for 24 hours or with Hep2G cells at concentrations up to 20 µM for 72 hours. None of the five tested compounds inhibited the ability of the ABCG2 transporter to transport the fluorescent substrate at concentrations up to 2 mM. Furthermore, no inhibition of CYP3A4 activity (measured as N-demethylation of erythromycin) was observed for CHB up to 2 mM.

CONCLUSION

This study suggests that under these conditions, the selected nitrile or epithionitrile derivatives of glucosinolates are not hepatotoxic in vitro.

Comparison of the effects on tablet disintegration of solvents used to dissolve food thickeners

Food thickening agents help patients with dysphagia to eat, drink, and take medications. Taking medications with food thickeners has been reported to cause problems such as reduction of pharmacological effects through the delayed disintegration or non-disintegration of tablets. We previously reported that long immersion periods in food thickeners causes delayed disintegration and non-disintegration, while an immersion time of 1 min prevents these problems. However, in many studies including ours, water was used as the solvent, and patients with dysphagia use various drinks as food thickener solvents. Therefore, in this study, we examined the effects on tablet disintegration of food thickeners dissolved in 12 solvents. The line spread test (LST) and pH of the food thickeners differed among solvents, whereas the disintegration times of tablets immersed in food thickeners for 1 min were similar. Magnesium oxide tablets immersed in food thickeners for 30 min experienced delayed disintegration or non-disintegration in all solvents. These results suggested that the effects of solvents on the disintegration of medications hardly differ. Therefore, patients taking medications with food thickeners may refer to reports in which water was used as the solvent, regardless of their drink of choice.

Food-Drug Interactions with Fruit Juices

Fruit juices contain a large number of phytochemicals that, in combination with certain drugs, can cause food–drug interactions that can be clinically significant and lead to adverse events. The mechanisms behind such interactions are in most cases related to phytochemical interference with the activity of cytochrome P450 metabolizing enzymes (CYPs) or drug transporters. Moreover, alterations in their activity can have a clinical relevance if systemic exposure to the drug is decreased or increased, meaning that the pharmacological drug effects are suboptimal, or the drug will cause toxicity. In general, the common pharmacokinetic parameters found to be altered in food–drug interactions regarding fruit juices are the area under the concentration–time curve, bioavailability, and maximum plasma concentration. In most cases, the results from the drug interaction studies with fruit juices provide only limited information due to the small number of subjects, which are also healthy volunteers. Moreover, drug interactions with fruit juices are challenging to predict due to the unknown amounts of the specific phytochemicals responsible for the interaction, as well as due to the inter-individual variability of drug metabolism, among others. Therefore, this work aims to raise awareness about possible pharmacological interactions with fruit juices.

Chemical Characterisation and Antihypertensive Effects of Locular Gel and Serum of Lycopersicum esculentum L. var. "Camone" Tomato in Spontaneously Hypertensive Rats

Blood pressure control in hypertensive subjects calls for changes in lifestyle, especially diet. Tomato is widely consumed and rich in healthy components (i.e., carotenoids, vitamins and polyphenols). The aim of this study was to evaluate the chemical composition and antihypertensive effects of locular gel reconstituted in serum of green tomatoes of "Camone" variety. Tomato serum and locular gel were chemically characterised. The antihypertensive effects of the locular gel in serum, pure tomatine, and captopril, administered by oral gavage, were investigated for 4 weeks in male spontaneously hypertensive and normotensive rats. Systolic blood pressure and heart rate were monitored using the tail cuff method. Body and heart weight, serum glucose, triglycerides and inflammatory cytokines, aorta thickness and liver metabolising activity were also assessed. Locular gel and serum showed good tomatine and polyphenols content. Significant reductions in blood pressure and heart rate, as well as in inflammatory blood cytokines and aorta thickness, were observed in spontaneously hypertensive rats treated both with locular gel in serum and captopril. No significant effects were observed in normotensive rats. Green tomatoes locular gel and serum, usually discarded during tomato industrial processing, are rich in bioactive compounds (i.e., chlorogenic acid, caffeic acid and rutin, as well as the glycoalkaloids, α-tomatine and dehydrotomatine) that can lower in vivo blood pressure towards healthier values, as observed in spontaneously hypertensive rats.

Food and lipid intake alters the pharmacokinetics of cyclosporine in kidney transplants

Prevention of kidney graft rejection with cyclosporine leads to a large interindividual pharmacokinetic variability. However, food intake is likely to alter cyclosporine pharmacokinetics, and therefore its efficacy. The aim of our study was to evaluate the influence of food and lipid intake on cyclosporine pharmacokinetics. Twenty-four kidney grafted patients treated with Neoral® were included in this prospective monocentric study. In all patients, the pharmacokinetics of cyclosporine was evaluated in two occasions, after meal ('feed') and without meal ('fasting'). At each occasion, blood samples were collected at trough, and 0.5, 1, 2, 3, and 4 h after administration. Cyclosporine pharmacokinetics was described using a Bayesian pharmacokinetic model including two-compartments with first-order transfer and elimination rate constants, and a gamma absorption model. Influence of meal or olive oil, very common in Morocco, was tested as covariates on interoccasion variability parameters. Cyclosporine concentration-time data were satisfactorily described using the Bayesian pharmacokinetic model. Food intake significantly increased volume of distribution and decreased elimination of cyclosporine. The influence of oil intake explained a large part of this effect, suggesting that lipid intake was the main factor of pharmacokinetic variability due to food. This intake resulted in a decrease in area under the concentration curve between two administrations of 14.6%. Food, and especially lipid intake is likely to decrease the exposure to cyclosporine and may therefore lead to a decrease in treatment efficacy. Therefore, to ensure optimal immunosuppression in time, meal composition should remain as steady as possible.

Effect of pineapple juice on the pharmacokinetics of celecoxib and montelukast in humans

Aim: To study the influence of pineapple juice on the pharmacokinetics of celecoxib and montelukast in humans. Experimental methods: The research comprised two separate arms. Each arm was randomized, two-crossover periods separated by a 2-week washout period. Subjects received a single dose of celecoxib or montelukast after pretreatment with either water or pineapple juice for 4 days before the study beginning. Results & conclusion: Pineapple juice enhanced the systemic exposure of both drugs without any noticeable adverse effects. For celecoxib, C_max and AUC_0-∞ were increased significantly by 40 and 60%, respectively. Cl/F was decreased by 45% without affecting its t_1/2. For montelukast, C_max and AUC_0-∞ were significantly increased by 21 and 48%, respectively, along with 25% decrease in clearance and 13% increase in t_1/2.

Review on Preclinical and Clinical Evidence of Food (Beverages, Fruits and Vegetables) and Drug Interactions: Mechanism and Safety

Background:

The therapeutic potency and efficacy of drugs can be affected by a patient’s dietary habit. The food composition and their nutritional value interact with drugs that lead to alteration of the therapeutic response of drugs in patients.

Objective:

This present review is an attempt to illustrate clinical reports of food-drug interaction. Further, it also highlights specific interaction mechanism(s) and the safety thereof.

Methods:

Through the search engine “Scopus”; literature on recent advances in food and drug interactions includes almost all therapeutic categories such as antimicrobials, antiviral, antifungal, antihistamines, anticoagulants, non-steroidal anti-inflammatory drugs, and drugs acting on the central nervous system and cardiovascular system.

Results:

Preclinical and clinical studies that have been conducted by various researchers affirm significant drug-food interactions across the various therapeutic categories of drugs. Preclinical studies have documented the effects of food, milk products, alcohols, fruit and vegetables on the drug absorption, metabolizing enzymes and drug transporters. The clinical studies on fruits/vegetables and drugs interactions report significant alteration in therapeutic response.

Conclusion:

Based on the preclinical and clinical reports, it can be concluded that the interaction of food with drug(s) significantly alters their therapeutic potential. The inputs from clinical practitioners to elucidate potential risk of food-drug interaction need to be intensified in order to prevent adverse clinical consequences.

What do laypeople consider 'medication' and are they aware of modulators of a drug's effects?

Objectives

Healthcare providers expect patients to be responsible partners during drug treatment, who know potential risks impeding drug effects and are able to accurately report prescribed and non-prescribed medication. This presumes that they have the same understanding of the term 'medication' as healthcare providers. We assessed which products laypeople label as medication and which modulators of drug effects they know.

Methods

People visiting the otorhinolaryngology outpatient clinic at a university hospital were invited to anonymously complete a questionnaire assessing which products out of 23 listed examples are medications and valuing 12 modulators potentially influencing drug effects.

Results

Among 94 participants, 86 (91.5%) identified on average 14.4±3.3 (62.6%) of the products and 79 (84.0%) identified 6.7±2.0 (55.5%) of the modulators correctly. Women performed better than men (p<0.01). Regular medication intake, education level and age did not influence the results.

Conclusions

Laypeople are at risk of misclassifying medications and modulators of drug effects.

The mechanisms of pharmacokinetic food-drug interactions - A perspective from the UNGAP group

The simultaneous intake of food and drugs can have a strong impact on drug release, absorption, distribution, metabolism and/or elimination and consequently, on the efficacy and safety of pharmacotherapy. As such, food-drug interactions are one of the main challenges in oral drug administration. Whereas pharmacokinetic (PK) food-drug interactions can have a variety of causes, pharmacodynamic (PD) food-drug interactions occur due to specific pharmacological interactions between a drug and particular drinks or food. In recent years, extensive efforts were made to elucidate the mechanisms that drive pharmacokinetic food-drug interactions. Their occurrence depends mainly on the properties of the drug substance, the formulation and a multitude of physiological factors. Every intake of food or drink changes the physiological conditions in the human gastrointestinal tract. Therefore, a precise understanding of how different foods and drinks affect the processes of drug absorption, distribution, metabolism and/or elimination as well as formulation performance is important in order to be able to predict and avoid such interactions. Furthermore, it must be considered that beverages such as milk, grapefruit juice and alcohol can also lead to specific food-drug interactions. In this regard, the growing use of food supplements and functional food requires urgent attention in oral pharmacotherapy. Recently, a new consortium in Understanding Gastrointestinal Absorption-related Processes (UNGAP) was established through COST, a funding organisation of the European Union supporting translational research across Europe. In this review of the UNGAP Working group "Food-Drug Interface", the different mechanisms that can lead to pharmacokinetic food-drug interactions are discussed and summarised from different expert perspectives.

Food Bioactive Compounds and Their Interference in Drug Pharmacokinetic/Pharmacodynamic Profiles

Preclinical and clinical studies suggest that many food molecules could interact with drug transporters and metabolizing enzymes through different mechanisms, which are predictive of what would be observed clinically. Given the recent incorporation of dietary modifications or supplements in traditional medicine, an increase in potential food-drug interactions has also appeared. The objective of this article is to review data regarding the influence of food on drug efficacy. Data from Google Scholar, PubMed, and Scopus databases was reviewed for publications on pharmaceutical, pharmacokinetic, and pharmacodynamic mechanisms. The following online resources were used to integrate functional and bioinformatic results: FooDB, Phenol-Explorer, Dr. Duke's Phytochemical and Ethnobotanical Databases, DrugBank, UniProt, and IUPHAR/BPS Guide to Pharmacology. A wide range of food compounds were shown to interact with proteins involved in drug pharmacokinetic/pharmacodynamic profiles, starting from drug oral bioavailability to enteric/hepatic transport and metabolism, blood transport, and systemic transport/metabolism. Knowledge of any food components that may interfere with drug efficacy is essential, and would provide a link for obtaining a holistic view for cancer, cardiovascular, musculoskeletal, or neurological therapies. However, preclinical interaction may be irrelevant to clinical interaction, and health professionals should be aware of the limitations if they intend to optimize the therapeutic effects of drugs.

Selected Food/Herb-Drug Interactions: Mechanisms and Clinical Relevance

BACKGROUND

Food/Herb-drug interactions have become a major problem in health care. These interactions can lead to loss of therapeutic efficacy or toxic effects of drugs.

AREAS OF UNCERTAINTY

To probe the clinical relevance of such interactions, the impact of food/herb intake on the clinical effects of drug administration has to be evaluated. Failure to identify and efficiently manage food-drug interactions can lead to serious consequences. A comprehensive knowledge of the mechanisms that underpin variability in disposition will help optimize therapy.

DATA SOURCES

Electronic search of literatures from relevant databases were conducted. A total of 58 original scientific reports/review articles were obtained with the search strategy; of which 25 were found eligible to be included in the present review. Required data were extracted from these studies, and their methodologies were assessed.

RESULTS AND CONCLUSIONS

This review updates our knowledge on clinical food-drug interactions with emphasis on mechanism and clinical implications. Results obtained from literature search identified interactions with selected foods/herbs generated from in vivo and in vitro studies. For example, interaction studies in humans revealed a reduction in the bioavailability of mercaptopurine when taken concurrently with substances containing xanthine oxidase (eg, cow milk); a reduction in the bioavailability of quinine with Garcinia kola; increased bioavailability/toxicity of felodipine, nifedipine, saquinavir, sildenafil with grape juice; increased bioavailability of felodipine, cisapride with red wine and diminished bioavailability of fexofenadine with apple. Pharmacokinetic and/or pharmacodynamic mechanisms are implicated in many of these interactions. By evaluating the dietary patterns of patients and use of prescribed medications, health professionals will be well informed of potential interactions and associated adverse effects.

Warfarin Safety: A Cross-Sectional Study of the Factors Associated with the Consumption of Medicinal Plants in a Brazilian Anticoagulation Clinic

OBJECTIVE

The aim of this study was to analyze factors associated with the consumption of medicinal plants by patients being treated with warfarin in a Brazilian anticoagulation clinic and to study the safety of medicinal plant use in patients on warfarin therapy.

METHODS

The study was performed as an observational cross-sectional analysis. Study participants were outpatients on long-term warfarin therapy for at least 2 months for atrial fibrillation or prosthetic cardiac valves. Interviews were carried out concerning information about the habits of medicinal herb consumption, and logistic regression analysis was performed to identify factors associated with the consumption of herbs. The scientific names of the medicinal plants were identified to search for information on the effects on the hemostasis of the interactions between the medicinal herbs reported and warfarin.

RESULTS

The mean age of the 273 patients included was 60.8 years; 58.7% were women. Medicinal plants were used by 67% of the participants. No association between demographic and clinical data and the use of medicinal plants was identified. Patients reported a total of 64 different plants, primarily consumed in the form of tea. The plants were mainly used to treat respiratory tract and central nervous system disorders. About 40% of the plants cited have been reported to potentially interfere with the anticoagulation therapy, principally by potentiating the effects of warfarin, which could, increase the risk of bleeding.

CONCLUSION

The use of medicinal plants was highly common and widespread in patients receiving warfarin as an anticoagulation therapy. Univariate analysis of variables associated with the consumption of herbs showed no statistically significant difference in the consumption of medicinal plants for any of the sociodemographic and clinical data. The medicinal plants that were reportedly consumed by the patients could affect hemostasis. This study reinforces the need for further studies evaluating the habits of patients consuming medicinal plants and their clinical implications, and will help to design strategies to manage the risks associated with warfarin-herbal interactions.

Inhibitory effects of Danhong Injection and its major constituents on human cytochrome P450 enzymes in vitro

Danhong Injection (DHI) as a Chinese patent medicine is mainly used to treat ischemic encephalopathy and coronary heart disease in combination with other chemotherapy. However, the information on DHI's potential drug interactions is limited. The goal of this work was to examine the potential P450-mediated metabolism drug interaction arising from DHI and its active components. The results showed that DHI inhibited CYP2C19, CYP2D6, CYP3A4, CYP2E1 and CYP2C9 with IC₅₀ values of 1.26, 1.42, 1.63, 1.10 and 1.67% (v/v), respectively. Danshensu and rosmarinic acid inhibited CYP2E1 and CYP2C9 with IC₅₀ values of 36.63 and 75.76 μm, and 34.42 and 76.89 μm, respectively. Salvianolic acid A and B inhibited CYP2D6, CYP2E1 and CYP2C9 with IC₅₀ values of 33.79, 21.64 and 31.94 μm, and 45.47, 13.52 and 24.15 μm, respectively. The study provides some useful information for safe and effective use of DHI in clinical practice.

Potential Functional Byproducts from Guava Purée Processing

The valorization of guava waste requires compositional and functional studies. We tested three byproducts of guava purée processing, namely refiner, siever, and decanter. We analyzed the chemical composition and quantified the prebiotic activity score and selected carbohydrates; we also determined the water holding (WHC), oil holding (OHC), cation exchange capacities, bile acid binding, and glucose dialysis retardation (GDR) of the solid fraction and the antioxidative and α-amylase inhibitory capacities (AIC) of the ethanolic extract. Refiner contained 7.7% lipid, 7.08% protein and a relatively high phytate content; it had a high prebiotic activity score and possessed the highest binding capacity with deoxycholic acid. Siever contained high levels of low molecular weight carbohydrates and total tannin but relatively low crude fiber and cellulose contents. It had the highest binding with chenodeoxycholic acid (74.8%), and exhibited the highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity. Decanter was rich in cellulose and had a high prebiotic activity score. The WHC and OHC values of decanter were within a narrow range and also exhibited the highest binding with cholic acid (86.6%), and the highest values of GDR and AIC. The refiner waste could be included in animal feed but requires further processing to reduce the high phytate levels. All three guava byproducts had the potential to be a source of antioxidant dietary fiber (DF), a finding that warrants further in vivo study.

PRACTICAL APPLICATION

To differing extents, the guava byproducts exhibited useful physicochemical binding properties and so possessed the potential for health-promoting activity. These byproducts could also be upgraded to other marketable products so the manufacturers of processed guava might be able to develop their businesses sustainably by making better use of them.

Bitter and sweet tasting molecules: It's complicated

"Bitter" and "sweet" are frequently framed in opposition, both functionally and metaphorically, in regard to affective responses, emotion, and nutrition. This oppositional relationship is complicated by the fact that some molecules are simultaneously bitter and sweet. In some cases, a small chemical modification, or a chirality switch, flips the taste from sweet to bitter. Molecules humans describe as bitter are recognized by a 25-member subfamily of class A G-protein coupled receptors (GPCRs) known as TAS2Rs. Molecules humans describe as sweet are recognized by a TAS1R2/TAS1R3 heterodimer of class C GPCRs. Here we characterize the chemical space of bitter and sweet molecules: the majority of bitter compounds show higher hydrophobicity compared to sweet compounds, while sweet molecules have a wider range of sizes. Importantly, recent evidence indicates that TAS1Rs and TAS2Rs are not limited to the oral cavity; moreover, some bitterants are pharmacologically promiscuous, with the hERG potassium channel, cytochrome P450 enzymes, and carbonic anhydrases as common off-targets. Further focus on polypharmacology may unravel new physiological roles for tastant molecules.

The effect of lycopene on cytochrome P450 isoenzymes and P-glycoprotein by using human liver microsomes and Caco-2 cell monolayer model

Lycopene is widely used as a dietary supplement. However, the effects of lycopene on cytochrome P450 (CYP) enzymes or P-glycoprotein (P-gp) are not comprehensive. The present study was performed to investigate the effects of lycopene on the CYP enzymes and P-gp activity. A cocktail method was used to evaluate the activities of CYP3A4, CYP2C9, CYP2C19, CYP2D6 and CYP2E1. Caco-2 cell monolayer model was carried out to assay lycopene on P-gp activity. The results indicated that lycopene had a moderate inhibitory effect on CYP2E1, with IC50 value of 43.65 μM, whereas no inhibitory effects on CYP3A4, CYP2C19, CYP2D6 and CYP2E1, with IC50 values all over 100 μM. In addition, lycopene showed almost no inhibitory effect on rhodamine-123 efflux and uptake (p > .05), indicated no effects on P-gp activity. In conclusion, there should be required attention when lycopene are coadministered with other drugs that are metabolised by CYP2E1.

Food and Sex-Related Impacts on the Pharmacokinetics of a Single-Dose of Ginsenoside Compound K in Healthy Subjects

Background and Objectives: Ginsenoside compound K (CK) is a candidate drug for rheumatoid arthritis therapy. This clinical trial was designed to evaluate the effects of food and sex on the pharmacokinetics of CK and its metabolite 20(S)-protopanaxadiol (PPD).

Methods: An open-label, single-center, two-period crossover trial was performed in healthy Chinese subjects (n = 24; male = 12, female = 12), randomized to either the fasting overnight or the high-fat meal group before a single 200 mg dose of monomer CK was administered. According to the concentration-time data of plasma and urine samples from each subject, the pharmacokinetic parameters of CK and 20(S)-PPD were calculated and statistically analyzed.

Results: A two-way ANOVA test combined with mean plots showed no statistically significant interaction between food and sex. High-fat meal accelerated the absorption of CK, with t_max being shortened from 3.6 to 2.5 h (p = 0.015). In contrast, food significantly increased the C_max, AUC_last, and AUC_inf(p < 0.001) with the 90% confidence intervals falling outside of the conventional 0.80–1.25. Females had higher exposure levels of CK than males, but the difference was statistically significant only after a high-fat meal. Of note, CK was rarely excreted in urine. Furthermore, the effects of food and sex were also observed on 20(S)-PPD.

Conclusion: High-fat food and sex both had an impact on the disposition of CK in vivo, but rather than a significant interaction effect. High-fat food accelerated and increased the absorption of CK, while the exposure of CK was higher in females compared to males. The results indicate that food and sex should be two noteworthy factors in future research on CK.

Biomarkers of carotenoid bioavailability

The use of biomarkers constitutes an essential tool to assess the bioavailability of carotenoids in humans. The present article aims to review several methodological, host-related and modulating factors relevant on assessing and interpreting carotenoid bioavailability. Markers for carotenoid bioavailability can be broadly divided into direct, biochemical or "analytical" markers and indirect, physiological or "functional" indicators. Analytical markers usually refer to biochemical indicators of intake and/or status (short and long term exposure) while functional measures may be interpreted in terms of cumulative exposure, biological effect (bioactivity) or modification of risk factors. Both types of markers display advantages and limitations but, in general, a relationship exists among the type of marker, the biological specimen needed and the time required for a change. Humans may absorb a wide range of carotenes and xanthophylls and many of them may be found in serum and tissues. However, under physiological conditions, the several classes of dietary carotenoids may behave unequally leading to a different systemic profile and, moreover, they can be selectively accumulated at target tissues. In addition, some carotenoids may be chemically and enzymatically modified generating different oxidative metabolites and apocarotenoids. Quantitatively, the biological response upon carotenoid intervention (assessed by analytical and functional markers) is highly variable but the use of large doses and long-term protocols may lead to saturation effects and the loss of linearity in the response. Also, despite carotenoid exposition is considered to be safe, markers of overexposure include clinical signs (i.e. carotenodermia, corneal rings and retinopathy) and biochemical indicators (hypercarotenemia, xanthophyll esters). Overall, both host-related and methodological factors may influence analytical and functional markers to assess carotenoid bioavailability although the different subclasses of carotenoids may not be equally affected.

Prioritizing pharmacokinetic drug interaction precipitants in natural products: application to OATP inhibitors in grapefruit juice

Natural products, including botanical dietary supplements and exotic drinks, represent an ever-increasing share of the health-care market. The parallel ever-increasing popularity of self-medicating with natural products increases the likelihood of co-consumption with conventional drugs, raising concerns for unwanted natural product-drug interactions. Assessing the drug interaction liability of natural products is challenging due to the complex and variable chemical composition inherent to these products, necessitating a streamlined preclinical testing approach to prioritize precipitant individual constituents for further investigation. Such an approach was evaluated in the current work to prioritize constituents in the model natural product, grapefruit juice, as inhibitors of intestinal organic anion-transporting peptide (OATP)-mediated uptake. Using OATP2B1-expressing MDCKII cells (Madin-Darby canine kidney type II) and the probe substrate estrone 3-sulfate, IC_50s were determined for constituents representative of the flavanone (naringin, naringenin, hesperidin), furanocoumarin (bergamottin, 6',7'-dihydroxybergamottin) and polymethoxyflavone (nobiletin and tangeretin) classes contained in grapefruit juice. Nobiletin was the most potent (IC₅₀ , 3.7 μm); 6',7'-dihydroxybergamottin, naringin, naringenin and tangeretin were moderately potent (IC₅₀ , 20-50 μm); and bergamottin and hesperidin were the least potent (IC₅₀ , >300 μm) OATP2B1 inhibitors. Intestinal absorption simulations based on physiochemical properties were used to determine the ratios of unbound concentration to IC₅₀ for each constituent within enterocytes and to prioritize in order of pre-defined cut-off values. This streamlined approach could be applied to other natural products that contain multiple precipitants of natural product-drug interactions. Copyright © 2016 John Wiley & Sons, Ltd.

Food and Drug Interactions

Natural foods and vegetal supplements have recently become increasingly popular for their roles in medicine and as staple foods. This has, however, led to the increased risk of interaction between prescribed drugs and the bioactive ingredients contained in these foods. These interactions range from pharmacokinetic interactions (absorption, distribution, metabolism, and excretion influencing blood levels of drugs) to pharmacodynamic interactions (drug effects). In a quantitative respect, these interactions occur mainly during metabolism. In addition to the systemic metabolism that occurs mainly in the liver, recent studies have focused on the metabolism in the gastrointestinal tract endothelium before absorption. Inhibition of metabolism causes an increase in the blood levels of drugs and could have adverse reactions. The food-drug interactions causing increased blood levels of drugs may have beneficial or detrimental therapeutic effects depending on the intensity and predictability of these interactions. It is therefore important to understand the potential interactions between foods and drugs should and the specific outcomes of such interactions.

Phytotherapeutic approach: a new hope for polycyclic aromatic hydrocarbons induced cellular disorders, autophagic and apoptotic cell death

Polycyclic aromatic hydrocarbons (PAHs) comprise the major class of cancer-causing chemicals and are ranked ninth among the chemical compounds threatening to humans. Moreover, interest in PAHs has been mainly due to their genotoxic, teratogenic, mutagenic and carcinogenic property. Polymorphism in cytochrome P450 (CYP450) and aryl hydrocarbon receptor (AhR) has the capacity to convert procarcinogens into carcinogens, which is an imperative factor contributing to individual susceptibility to cancer development. The carcinogenicity potential of PAHs is related to their ability to bind to DNA, thereby enhances DNA cross-linking, causing a series of disruptive effects which can result in tumor initiation. They induce cellular toxicity by regulating the generation of reactive oxygen species (ROS), which arbitrate apoptosis. Additionally, cellular toxicity-mediated apoptotic and autophagic cell death and immune suppression by industrial pollutants PAH, provide fertile ground for the proliferation of mutated cells, which results in cancer growth and progression. PAHs play a foremost role in angiogenesis necessary for tumor metastasization by promoting the upregulation of metalloproteinase-9 (MMP-9), vascular endothelial growth factor (VEGF) and hypoxia inducible factor (HIF) in human cancer cells. This review sheds light on the molecular mechanisms of PAHs induced cancer development as well as autophagic and apoptotic cell death. Besides that authors have unraveled how phytotherapeutics is an alternate potential therapeutics acting as a savior from the toxic effects of PAHs for safer and cost effective perspectives.

Multiple-Ascending-Dose Pharmacokinetics and Safety Evaluation of Baicalein Chewable Tablets in Healthy Chinese Volunteers

BACKGROUND AND OBJECTIVES

Baicalein, a flavonoid isolated from the root of Scutellaria baicalensis Georgi, is a neuroprotective agent under development to treat Parkinson's disease. This study investigated the pharmacokinetics, safety and tolerability of baicalein after a multiple-ascending-dose protocol in healthy Chinese volunteers.

METHODS

In this single-center, double-blind, placebo-controlled, parallel-group study, participants were randomized to receive baicalein (n = 8 per dose regimen) or placebo (n = 2 per dose regimen). Dosing regimens were 200, 400, and 800 mg once daily on days 1 and 10, twice daily on days 3-9. Plasma, urine, and feces samples were assayed for baicalein and its predominant metabolite baicalin using validated HPLC-MS/MS methods. Pharmacokinetic parameters were computed using standard non-compartmental analysis. Dose proportionality was assessed with a method combining equivalence criterion and power model. Drug safety and tolerability were assessed by monitoring adverse events and laboratory parameters.

RESULTS

Thirty-three of 36 enrolled participants completed the study. A total of 44 adverse events occurred in 23 participants. A steady-state concentration of analytes in plasma was achieved on day 8 after repeated dosing. Analytes concentrations and exposure increased with increasing dose. The dose proportionality constant (β) for AUCss of baicalein and baicalin was 0.922 (90 % confidence interval, 0.650-1.195) and 0.942 (90 % confidence interval, 0.539-1.345), respectively. The accumulation index varied from 1.66 to 2.07 for baicalein and from 1.68 to 2.45 for baicalin.

CONCLUSION

In dose range of 200-800 mg, multiple-dose oral baicalein administration was safe and well tolerated, dose proportionality was inconclusive, and no serious accumulation of baicalein was observed.

The role of metabolism (and the microbiome) in defining the clinical efficacy of dietary flavonoids

At a population level, there is growing evidence of the beneficial effects of dietary flavonoids on health. However, there is extensive heterogeneity in the response to increased intake, which is likely mediated via wide interindividual variability in flavonoid absorption and metabolism. Flavonoids are extensively metabolized by phase I and phase II metabolism (which occur predominantly in the gastrointestinal tract and liver) and colonic microbial metabolism. A number of factors, including age, sex, and genotype, may affect these metabolic processes. In addition, food composition and flavonoid source are likely to affect bioavailability, and emerging data suggest a critical role for the microbiome. This review will focus on the current knowledge for the main subclasses of flavonoids, including anthocyanins, flavonols, flavan-3-ols, and flavanones, for which there is growing evidence from prospective studies of beneficial effects on health. The identification of key factors that govern metabolism and an understanding of how the differential capacity to metabolize these bioactive compounds affect health outcomes will help establish how to optimize intakes of flavonoids for health benefits and in specific subgroups. We identify research areas that need to be addressed to further understand important determinants of flavonoid bioavailability and metabolism and to advance the knowledge base that is required to move toward the development of dietary guidelines and recommendations for flavonoids and flavonoid-rich foods.

Lotus leaf alkaloid fraction can strongly inhibit CYP2D6 isoenzyme activity

ETHNOPHARMACOLOGICAL RELEVANCE

The Chinese herbal medicine He-Ye, the leaves of the lotus (Nelumbo nucifera) plant, is traditionally used in China for the treatment of sunstroke, thirst, diarrhea, and fever. Currently, the leaf is used not only as an herbal tea to reduce lipid level and control body weight, but also as a major ingredient in some lipid-lowering Chinese patented medicines. Our previous study demonstrated that the alkaloid fraction (AF) of the herb has a strong inhibitory effect on CYP2D6 isoenzyme activity in vitro. The present study aims to further verify this activity using the in vivo rat model and to explore the inhibitory mechanism on CYP2D6 using human liver microsomes (HLMs).

MATERIALS AND METHODS

After a continuous 7-d oral dose of AF (50mg/kg) or a vehicle, Sprague Dawley rats received a single intravenous dose of dextromethorphan or metoprolol. Blood samples were collected at various time points, and the plasma concentrations of the relevant metabolites dextrorphan and hydroxymetoprolol were assayed by LC-MS/MS for evaluating the effect of AF on their pharmacokinetics and CYP2D6 activity. Dextromethorphan as a probe at different concentrations was incubated with HLMs in an incubation buffer system, in the presence or absence of AF at different concentrations. After incubation, the produced metabolite was assayed.

RESULTS

After being pretreated with AF in rats, the plasma concentrations of dextrorphan and hydroxymetoprolol significantly decreased, with C_max going from 79.44 to 29.96 and 151.18 to 83.39hng/mL (P<0.05), AUC_all from 167.27 to 62.25 and 347.68 to 223.24hng/mL (P<0.05), and AUC_inf from 183.39 to 84.76 and 350.59 to 234.57hng/mL (P<0.05), respectively, in comparison with those of untreated rats. The t_1/2 of hydroxymetoprolol significantly increased from 1.14 to 1.99h (P<0.05). The in vitro incubation test showed that AF competitively inhibited the CYP2D6, with apparent K_i value of 0.64µg/mL.

CONCLUSIONS

AF can strongly inhibit the activity of CYP2D6 enzyme, as confirmed by in vivo and in vitro models. Possible drug interactions may occur between AF and other medications metabolized by CYP2D6. Thus, caution should be paid when the lotus leaf and its preparations are concurrently administered with conventional medicines.

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.

Is the clinical relevance of drug-food and drug-herb interactions limited to grapefruit juice and Saint-John's Wort?

An interaction of drug with food, herbs, and dietary supplements is usually the consequence of a physical, chemical or physiologic relationship between a drug and a product consumed as food, nutritional supplement or over-the-counter medicinal plant. The current educational review aims at reminding to the prescribing physicians that the most clinically relevant drug-food interactions may not be strictly limited to those with grapefruit juice and with the Saint John's Wort herbal extract and may be responsible for changes in drug plasma concentrations, which in turn decrease efficacy or led to sometimes life-threatening toxicity. Common situations handled in clinical practice such as aging, concomitant medications, transplant recipients, patients with cancer, malnutrition, HIV infection and those receiving enteral or parenteral feeding may be at increased risk of drug-food or drug-herb interactions. Medications with narrow therapeutic index or potential life-threatening toxicity, e.g., the non-steroidal anti-inflammatory drugs, opioid analgesics, cardiovascular medications, warfarin, anticancer drugs and immunosuppressants may be at risk of significant drug-food interactions to occur. Despite the fact that considerable effort has been achieved to increase patient' and doctor's information and ability to anticipate their occurrence and consequences in clinical practice, a thorough and detailed health history and dietary recall are essential for identifying potential problems in order to optimize patient prescriptions and drug dosing on an individual basis as well as to increase the treatment risk/benefit ratio.

Effects of soy containing diet and isoflavones on cytochrome P450 enzyme expression and activity

Cytochromes P450 (CYPs) play an important role in metabolism and clearance of most clinically utilized drugs and other xenobiotics. They are important in metabolism of endogenous compounds including fatty acids, sterols, steroids and lipid-soluble vitamins. Dietary factors such as phytochemicals are capable of affecting CYP expression and activity, which may be important in diet-drug interactions and in the development of fatty liver disease, cardiovascular disease and cancer. One important diet-CYP interaction is with diets containing plant proteins, particularly soy protein. Soy diets are traditionally consumed in Asian countries and are linked to lower incidence of several cancers and of cardiovascular disease in Asian populations. Soy is also an important protein source in vegetarian and vegan diets and the sole protein source in soy infant formulas. Recent studies suggest that consumption of soy can inhibit induction of CY1 enzymes by polycyclic aromatic hydrocarbons (PAHs) which may contribute to cancer prevention. In addition, there are data to suggest that soy components promiscuously activate several nuclear receptors including PXR, PPAR and LXR resulting in increased expression of CYP3As, CYP4As and CYPs involved in metabolism of cholesterol to bile acids. Such soy-CYP interactions may alter drug pharmacokinetics and therapeutic efficacy and are associated with improved lipid homeostasis and reduced risk of cardiovascular disease. The current review summarizes results from in vitro; in vivo and clinical studies of soy-CYP interactions and examines the evidence linking the effects of soy diets on CYP expression to isoflavone phytoestrogens, particularly, genistein and daidzein that are associated with soy protein.

Anthocyanin can arrest the cone photoreceptor degeneration and act as a novel treatment for retinitis pigmentosa

Retinitis pigmentosa (RP) is a group of heterogeneous inherited retinal diseases that is characterized by primary death rod photoreceptors and the secondary loss of cones. The degeneration of cones causes gradual constriction of visual fields, leaving the central islands that are eventually snuffed out. Studies indicate that the hyperoxia causes oxidative damage in the retina and contributes to the cone death of RP. Moreover, abundant reactive oxidative species (ROS) which are generated in cones may result in mitochondria membrane depolarization, which has been ascribed a central role in the apoptotic process and has been proposed to act as a forward feeding loop for the activation of downstream cascades. Anthocyanin is a potent antioxidant which has been evidenced to be able to counteract oxidative damages, scavenge surplus ROS, and rectify abnormities in the apoptotic cascade. Taken together with its ability to attenuate inflammation which also contributes to the etiology of RP, it is reasonable to hypothesize that the anthocyanin could act as a novel therapeutic strategy to retard or prevent cone degeneration in RP retinas, particularly if the treatment is timed appropriately and delivered efficiently. Future pharmacological investigations will identify the anthocyanin as an effective candidate for PR therapy and refinements of that knowledge would ignite the hope of restoring the visual function in RP patients.