Trans-resveratrol, but not other natural stilbenes occurring in food, carries the risk of drug-food interaction via inhibition of cytochrome P450 enzymes or interaction with xenosensor receptors

Oxyresveratrol in Breast Cancer Cells: Synergistic Effect with Chemotherapeutics Doxorubicin or Melphalan on Proliferation, Cell Cycle Arrest, and Cell Death

Breast cancer is the second most common type of cancer in the world. Polyphenols can act at all stages of carcinogenesis and oxyresveratrol (OXY) promising anticancer properties, mainly associated with chemotherapy drugs. The aim of this study was to investigate the effect of OXY with doxorubicin (DOX) or melphalan (MEL), either isolated or associated, in MCF-7 and MDA-MB-231 breast cancer cells. Our results showed that OXY, DOX, and MEL presented cytotoxicity, in addition to altering cell morphology. The synergistic association of OXY + DOX and OXY + MEL reduced the cell viability in a dose-dependent manner. The OXY, DOX, or MEL and associations were able to alter the ROS production, ∆Ψm, and cell cycle; DOX and OXY + DOX led the cells to necrosis. Furthermore, OXY and OXY + MEL were able to lead the cells to apoptosis and upregulate caspases-3, -7, -8, and -9 in both cells. LC-HRMS showed that 7-deoxidoxorubicinone and doxorubicinol, responsible for the cardiotoxic effect, were not identified in cells treated with the OXY + DOX association. In summary, our results demonstrate for the first time the synergistic effect of OXY with chemotherapeutic agents in breast cancer cells, offering a new strategy for future animal studies.

Mini-encyclopedia of mitochondria-relevant nutraceuticals protecting health in primary and secondary care-clinically relevant 3PM innovation

Despite their subordination in humans, to a great extent, mitochondria maintain their independent status but tightly cooperate with the "host" on protecting the joint life quality and minimizing health risks. Under oxidative stress conditions, healthy mitochondria promptly increase mitophagy level to remove damaged "fellows" rejuvenating the mitochondrial population and sending fragments of mtDNA as SOS signals to all systems in the human body. As long as metabolic pathways are under systemic control and well-concerted together, adaptive mechanisms become triggered increasing systemic protection, activating antioxidant defense and repair machinery. Contextually, all attributes of mitochondrial patho-/physiology are instrumental for predictive medical approach and cost-effective treatments tailored to individualized patient profiles in primary (to protect vulnerable individuals again the health-to-disease transition) and secondary (to protect affected individuals again disease progression) care. Nutraceuticals are naturally occurring bioactive compounds demonstrating health-promoting, illness-preventing, and other health-related benefits. Keeping in mind health-promoting properties of nutraceuticals along with their great therapeutic potential and safety profile, there is a permanently growing demand on the application of mitochondria-relevant nutraceuticals. Application of nutraceuticals is beneficial only if meeting needs at individual level. Therefore, health risk assessment and creation of individualized patient profiles are of pivotal importance followed by adapted nutraceutical sets meeting individual needs. Based on the scientific evidence available for mitochondria-relevant nutraceuticals, this article presents examples of frequent medical conditions, which require protective measures targeted on mitochondria as a holistic approach following advanced concepts of predictive, preventive, and personalized medicine (PPPM/3PM) in primary and secondary care.

Enhancing drug-food interaction prediction with precision representations through multilevel self-supervised learning

Drug-food interactions (DFIs) crucially impact patient safety and drug efficacy by modifying absorption, distribution, metabolism, and excretion. The application of deep learning for predicting DFIs is promising, yet the development of computational models remains in its early stages. This is mainly due to the complexity of food compounds, challenging dataset developers in acquiring comprehensive ingredient data, often resulting in incomplete or vague food component descriptions. DFI-MS tackles this issue by employing an accurate feature representation method alongside a refined computational model. It innovatively achieves a more precise characterization of food features, a previously daunting task in DFI research. This is accomplished through modules designed for perturbation interactions, feature alignment and domain separation, and inference feedback. These modules extract essential information from features, using a perturbation module and a feature interaction encoder to establish robust representations. The feature alignment and domain separation modules are particularly effective in managing data with diverse frequencies and characteristics. DFI-MS stands out as the first in its field to combine data augmentation, feature alignment, domain separation, and contrastive learning. The flexibility of the inference feedback module allows its application in various downstream tasks. Demonstrating exceptional performance across multiple datasets, DFI-MS represents a significant advancement in food presentations technology. Our code and data are available at https://github.com/kkkayle/DFI-MS.

Therapeutic potential of stilbenes in neuropsychiatric and neurological disorders: A comprehensive review of preclinical and clinical evidence

Neuropsychiatric disorders are anticipated to be a leading health concern in the near future, emphasizing an outstanding need for the development of new effective therapeutics to treat them. Stilbenes, with resveratrol attracting the most attention, are an example of multi-target compounds with promising therapeutic potential for a broad array of neuropsychiatric and neurological conditions. This review is a comprehensive summary of the current state of research on stilbenes in several neuropsychiatric and neurological disorders such as depression, anxiety, schizophrenia, autism spectrum disorders, epilepsy, traumatic brain injury, and neurodegenerative disorders. We describe and discuss the results of both in vitro and in vivo studies. The majority of studies concentrate on resveratrol, with limited findings exploring other stilbenes such as pterostilbene, piceatannol, polydatin, tetrahydroxystilbene glucoside, or synthetic resveratrol derivatives. Overall, although extensive preclinical studies show the potential benefits of stilbenes in various central nervous system disorders, clinical evidence on their therapeutic efficacy is largely missing.

Comprehensive and critical view on the anti-inflammatory and immunomodulatory role of natural phenolic antioxidants

The immune response encompasses innate and adaptive immunity, each with distinct and specific activities. The innate immune system is constituted by phagocytic cells, macrophages, monocytes and neutrophils, the cascade system, and different classes of receptors such as toll-like receptors that are exploited by the innate immune cells. The adaptive immune system is antigen-specific, encompassing memory lymphocytes and the corresponding specific receptors. Inflammation is understood as an activation of different signaling pathways such as toll-like receptors or nuclear factor kappa-light-chain-enhancer of activated B cells, with an increase in nitric oxide, inflammatory cytokines and chemokines. Increased oxidative stress has been identified as main source of chronic inflammation. Phenolic antioxidants modulate the activities of lymphocytes and macrophages by impacting cytokines and nitric oxide release, exerting anti-inflammatory effect. The nuclear-factor kappa-light-chain-enhancer of activated B cells signaling pathway and the mitogen-activated protein kinase pathway are targeted, alongside an increase in nuclear factor erythroid 2-related factor mediated antioxidant response, triggering the activity of antioxidant enzymes. The inhibitive potential on phospholipase A2, cyclooxygenase and lipoxygenase in the arachidonic acid pathway, and the subsequent reduction in prostaglandin and leukotriene generation, reveals the potential of phenolics as inflammation antagonists. The immunomodulative potential encompasses the capacity to interfere with proinflammatory cytokine synthesis and with the expression of the corresponding genes. A diet rich in antioxidants can result in prevention of inflammation-related pathologies. More investigations are necessary to establish the role of these antioxidants in therapy. The appropriate delivery system and the prooxidant effects exhibited at large doses, or in the presence of heavy metal cations should be regarded.

Selected Plant-Derived Polyphenols as Potential Therapeutic Agents for Peripheral Artery Disease: Molecular Mechanisms, Efficacy and Safety

Vascular diseases, such as peripheral artery disease (PAD), are associated with diabetes mellitus and a higher risk of cardiovascular disease and even death. Surgical revascularization and pharmacological treatments (mainly antiplatelet, lipid-lowering drugs, and antidiabetic agents) have some effectiveness, but the response and efficacy of therapy are overly dependent on the patient’s conditions. Thus, the demand for new cures exists. In this regard, new studies on natural polyphenols that act on key points involved in the pathogenesis of vascular diseases and, thus, on PAD are of great urgency. The purpose of this review is to take into account the mechanisms that lead to endothelium dysfunction, such as the glycoxidation process and the production of advanced glycation end-products (AGEs) that result in protein misfolding, and to suggest plant-derived polyphenols that could be useful in PAD. Thus, five polyphenols are considered, baicalein, curcumin, mangiferin, quercetin and resveratrol, reviewing the literature in PubMed. The key molecular mechanisms and preclinical and clinical studies of each selected compound are examined. Furthermore, the safety profiles of the polyphenols are outlined, together with the unwanted effects reported in humans, also by searching the WHO database (VigiBase).

Targeting microbiota-host interactions with resveratrol on cancer: Effects and potential mechanisms of action

Resveratrol (RSV) is a natural polyphenolic compound detected in grapes, berries, and red wine. The anticancer activities of RSV have been observed in vivo and in vitro studies. However, the pharmacology mechanism of RSV is confusing due to its low bioavailability. According to studies of the metabolic characteristics of RSV, the gut intestine is a crucial site of its health benefits. Dietary RSV exhibits a profound effect on the gut microbiota structure and metabolic function. In addition, emerging evidence demonstrates a protective effect of RSV metabolites against carcinogenesis. Therefore, to better understand the anticancer mechanisms of dietary RSV, it is vital to evaluate the role of RSV-microbiota-host interactions in cancer therapy. In this review, we summarized significant findings on the anticancer activities of RSV based on epidemiological, experimental and clinical studies involved in investigating the metabolic characteristics and the traditional anticancer mechanisms of RSV. Special attention is given to the putative mechanisms involving microbiota-host interactions, such as the modulation of gut microecology and the anticancer effects of RSV metabolites. The changes in microbiota-host interactions after RSV supplementation play vital roles in cancer prevention and thus offering a new perspective on nutritional interventions to treat cancer.

Identifying Drug-Induced Liver Injury Associated With Inflammation-Drug and Drug-Drug Interactions in Pharmacologic Treatments for COVID-19 by Bioinformatics and System Biology Analyses: The Role of Pregnane X Receptor

Of the patients infected with coronavirus disease 2019 (COVID-19), approximately 14–53% developed liver injury resulting in poor outcomes. Drug-induced liver injury (DILI) is the primary cause of liver injury in COVID-19 patients. In this study, we elucidated liver injury mechanism induced by drugs of pharmacologic treatments against SARS-CoV-2 (DPTS) using bioinformatics and systems biology. Totally, 1209 genes directly related to 216 DPTS (DPTSGs) were genes encoding pharmacokinetics and therapeutic targets of DPTS and enriched in the pathways related to drug metabolism of CYP450s, pregnane X receptor (PXR), and COVID-19 adverse outcome. A network, constructed by 110 candidate targets which were the shared part of DPTSGs and 445 DILI targets, identified 49 key targets and four Molecular Complex Detection clusters. Enrichment results revealed that the 4 clusters were related to inflammatory responses, CYP450s regulated by PXR, NRF2-regualted oxidative stress, and HLA-related adaptive immunity respectively. In cluster 1, IL6, IL1B, TNF, and CCL2 of the top ten key targets were enriched in COVID-19 adverse outcomes pathway, indicating the exacerbation of COVID-19 inflammation on DILI. PXR-CYP3A4 expression of cluster 2 caused DILI through inflammation-drug interaction and drug-drug interactions among pharmaco-immunomodulatory agents, including tocilizumab, glucocorticoids (dexamethasone, methylprednisolone, and hydrocortisone), and ritonavir. NRF2 of cluster 3 and HLA targets of cluster four promoted DILI, being related to ritonavir/glucocorticoids and clavulanate/vancomycin. This study showed the pivotal role of PXR associated with inflammation-drug and drug-drug interactions on DILI and highlighted the cautious clinical decision-making for pharmacotherapy to avoid DILI in the treatment of COVID-19 patients.

Interactions of resveratrol and its metabolites (resveratrol-3-sulfate, resveratrol-3-glucuronide, and dihydroresveratrol) with serum albumin, cytochrome P450 enzymes, and OATP transporters

Resveratrol (RES) is a widely-known natural polyphenol which is also contained by several dietary supplements. Large doses of RES can result in high micromolar levels of its sulfate and glucuronide conjugates in the circulation, due to the high presystemic metabolism of the parent polyphenol. Pharmacokinetic interactions of RES have been extensively studied, while only limited data are available regarding its metabolites. Therefore, in the current study, we examined the interactions of resveratrol-3-sulfate (R3S), resveratrol-3-glucuronide, and dihydroresveratrol (DHR; a metabolite produced by the colon microbiota) with human serum albumin (HSA), cytochrome P450 (CYP) enzymes, and organic anion transporting polypeptides (OATP) employing in vitro models. Our results demonstrated that R3S and R3G may play a major role in the RES-induced pharmacokinetic interactions: (1) R3S can strongly displace the site I marker warfarin from HSA; (2) R3G showed similarly strong inhibitory action on CYP3A4 to RES; (3) R3S proved to be similarly strong (OATP1B1/3) or even stronger (OATP1A2 and OATP2B1) inhibitor of OATPs tested than RES, while R3G and RES showed comparable inhibitory actions on OATP2B1.

Complex interactions between nicotine and resveratrol in the Drosophila melanogaster wing spot test

Nicotine (NIC) and resveratrol (RES) are chemicals in tobacco and wine, respectively, that are widely consumed concurrently worldwide. NIC is an alkaloid known to be toxic, addictive and to produce oxidative stress, while RES is thought of as an antioxidant with putative health benefits. Oxidative stress can induce genotoxic damage, yet few studies have examined whether NIC is genotoxic in vivo. In vitro studies have shown that RES can ameliorate deleterious effects of NIC. However, RES has been reported to have both antioxidant and pro-oxidant effects, and an in vivo study reported that 0.011 mM RES was genotoxic. We used the Drosophila melanogaster wing spot test to determine whether NIC and RES, first individually and then in combination, were genotoxic and/or altered the cell division. We hypothesized that RES would modulate NIC’s effects. NIC was genotoxic in the standard (ST) cross in a concentration-independent manner, but not genotoxic in the high bioactivation (HB) cross. RES was not genotoxic in either the ST or HB cross at the concentrations tested. We discovered a complex interaction between NIC and RES. Depending on concentration, RES was protective of NIC’s genotoxic damage, RES had no interaction with NIC, or RES had an additive or synergistic effect, increasing NIC’s genotoxic damage. Most NIC, RES, and NIC/RES combinations tested altered the cell division in the ST and HB crosses. Because we used the ST and HB crosses, we demonstrated that genotoxicity and cell division alterations were modulated by the xenobiotic metabolism. These results provide evidence of NIC’s genotoxicity in vivo at specific concentrations. Moreover, NIC’s genotoxicity can be modulated by its interaction with RES in a complex manner, in which their interaction can lead to either increasing NIC’s damage or protecting against it.

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Nicotine was genotoxic at specific concentrations in the Drosophila wing spot test.

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Resveratrol protected against nicotine’s genotoxic effects at some concentrations.

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Resveratrol increased nicotine’s genotoxicity at specific concentrations.

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Nicotine and resveratrol have a complex interaction in vivo.

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Studying chemicals in combination in vivo may uncover unexpected interactions.

Effect of Myricetin on CYP2C8 Inhibition to Assess the Likelihood of Drug Interaction Using In Silico, In Vitro, and In Vivo Approaches

Myricetin, a bioflavonoid, is widely used as functional food/complementary medicine and has promising multifaceted pharmacological actions against therapeutically validated anticancer targets. On the other hand, CYP2C8 is not only crucial for alteration in the pharmacokinetics of drugs to cause drug interaction but also unequivocally important for the metabolism of endogenous substances like the formation of epoxyeicosatrienoic acids (EETs), which are considered as signaling molecules against hallmarks of cancer. However, there is hardly any information known to date about the effect of myricetin on CYP2C8 inhibition and, subsequently, the CYP2C8-mediated drug interaction potential of myricetin at the preclinical/clinical level. We aimed here to explore the CYP2C8 inhibitory potential of myricetin using in silico, in vitro, and in vivo investigations. In the in vitro study, myricetin showed a substantial effect on CYP2C8 inhibition in human liver microsomes using CYP2C8-catalyzed amodiaquine-N-deethylation as an index reaction. Considering the Lineweaver-Burk plot, the Dixon plot, and the higher α-value, myricetin is found to be a mixed type of CYP2C8 inhibitor. Moreover, in vitro-in vivo extrapolation data suggest that myricetin is likely to cause drug interaction at the hepatic level. The molecular docking study depicted a strong interaction between myricetin and the active site of the human CYP2C8 enzyme. Moreover, myricetin caused considerable elevation in the oral exposure of amodiaquine as a CYP2C8 substrate via a slowdown of amodiaquine clearance in the rat model. Overall, the potent action of myricetin on CYP2C8 inhibition indicates that there is a need for further exploration to avoid drug interaction-mediated precipitation of obvious adverse effects as well as to optimize anticancer therapy.

A comprehensive review on phytochemicals for fatty liver: are they potential adjuvants?

Non-alcoholic fatty liver disease (NAFLD) is considered the hepatic manifestation of metabolic syndrome and, as such, is associated with obesity. With the current and growing epidemic of obesity, NAFLD is already considered the most common liver disease in the world. Currently, there is no official treatment for the disease besides weight loss. Although there are a few synthetic drugs currently being studied, there is also an abundance of herbal products that could also be used for treatment. With the World Health Organization (WHO) traditional medicine strategy (2014-2023) in mind, this review aims to analyze the mechanisms of action of some of these herbal products, as well as evaluate toxicity and herb-drug interactions available in literature.

Cardiovascular Effects of Chocolate and Wine-Narrative Review

The consumption of food for pleasure is mainly associated with adverse health effects. This review was carried out to verify recent reports on the impact of chocolate and wine consumption on cardiovascular health, with a particular focus on atherosclerosis. On one side, these products have proven adverse effects on the cardiovascular system, but on the other hand, if consumed in optimal amounts, they have cardiovascular benefits. The submitted data suggest that the beneficial doses are 30–50 g and 130/250 mL for chocolate and wine, respectively, for women and men. The accumulated evidence indicates that the active ingredients in the products under consideration in this review are phenolic compounds, characterized by anti-inflammatory, antioxidant, and antiplatelet properties. However, there are also some reports of cardioprotective properties of other compounds such as esters, amines, biogenic amines, amino acids, fatty acids, mineral ingredients, and vitamins. Our narrative review has shown that in meta-analyses of intervention studies, consumption of chocolate and wine was positively associated with the beneficial outcomes associated with the cardiovascular system. In contrast, the assessment with the GRADE (Grading of Recommendations Assessment, Development and Evaluation) scale did not confirm this phenomenon. In addition, mechanisms of action of bioactive compounds present in chocolate and wine depend on some factors, such as age, sex, body weight, and the presence of additional medical conditions. Patients using cardiovascular drugs simultaneously with both products should be alert to the risk of pharmacologically relevant interactions during their use. Our narrative review leads to the conclusion that there is abundant evidence to prove the beneficial impact of consuming both products on cardiovascular health, however some evidence still remains controversial. Many authors of studies included in this review postulated that well-designed, longitudinal studies should be performed to determine the effects of these products and their components on atherosclerosis and other CVD (Cardiovascular Disease) disease.

Dietary phytochemicals as modulators of human pregnane X receptor

As a promiscuous xenobiotic sensor, pregnane X receptor (PXR) plays a crucial role in drug metabolism. Since dietary phytochemicals exhibit the potential to modulate human PXR, this review aims to summarize the plant-derived PXR modulators, including agonists, partial agonists, and antagonists. The crystal structures of the apo and ligand-bound forms of PXR especially that of PXR complexed with binary mixtures are summarized, in order to provide the structural basis for PXR binding promiscuity and synergistic activation of PXR by composite ligands. Furthermore, this review summarizes the characterized agonists, partial agonists, and antagonists of human PXR from botanical source. Contrary to PXR agonists, there are only a few antagonists obtained from botanical source due to the promiscuity of PXR. It is worth noting that trans-resveratrol and a series of methylindoles have been identified as partial agonists of PXR, both in activating PXR function, but also inhibiting the effect of other PXR agonists. Since antagonizing PXR function plays a crucial role in the prevention of drug-drug interactions and improvement of therapeutic efficacy, further research is necessary to screen more plant-derived PXR antagonists in the future. In summary, this review may contribute to understanding the roles of phytochemicals in food-drug and herb-drug interactions.

Comprehensive Investigation of Stereoselective Food Drug Interaction Potential of Resveratrol on Nine P450 and Six UGT Isoforms in Human Liver Microsomes

The stereoselectivity of the food drug inhibition potential of resveratrol on cytochrome P450s and uridine 5'-diphosphoglucuronosyl transferases was investigated in human liver microsomes. Resveratrol enantiomers showed stereoselective inhibition of CYP2C9, CYP3A, and UGT1A1. The inhibitions of CYP1A2, CYP2B6, and CYP2C19 by resveratrol were stereo-nonselective. The estimated K_i values determined for CYP1A2 were 13.8 and 9.2 μM for trans- and cis-resveratrol, respectively. Trans-resveratrol noncompetitively inhibited CYP3A and UGT1A1 activities with K_i values of 23.8 and 27.4 μM, respectively. Trans-resveratrol inhibited CYP1A2, CYP2C19, CYP2E1, and CYP3A in a time-dependent manner with K_i shift values >2.0, while cis-resveratrol time-dependently inhibited CYP2C19 and CYP2E1. The time-dependent inhibition of trans-resveratrol against CYP3A4, CYP2E1, CYP2C19, and CYP1A2 was elucidated using glutathione as a trapping reagent. This information helped the prediction of food drug interaction potentials between resveratrol and co-administered drugs which are mainly metabolized by UGT1A1, CYP1A2, CYP2C19, CYP2E1, and CYP3A.

Oxyresveratrol: Sources, Productions, Biological Activities, Pharmacokinetics, and Delivery Systems

Oxyresveratrol has recently attracted much research attention due to its simple chemical structure and diverse therapeutic potentials. Previous reviews describe the chemistry and biological activities of this phytoalexin, but additional coverage and greater accessibility are still needed. The current review provides a more comprehensive summary, covering research from 1955 to the present year. Oxyresveratrol occurs in both gymnosperms and angiosperms. However, it has never been reported in plants in the subclass Sympetalae, and this point might be of both chemotaxonomic and biosynthetic importance. Oxyresveratrol can be easily obtained from plant materials by conventional methods, and several systems for both qualitative and quantitative analysis of oxyresveratrol contents in plant materials and plant products are available. Oxyresveratrol possesses diverse biological and pharmacological activities such as the inhibition of tyrosinase and melanogenesis, antioxidant and anti-inflammatory activities, and protective effects against neurological disorders and digestive ailments. However, the unfavorable pharmacokinetic properties of oxyresveratrol, including low water solubility and poor oral availability and stability, have posed challenges to its development as a useful therapeutic agent. Recently, several delivery systems have emerged, with promising outcomes that may improve chances for the clinical study of oxyresveratrol.

Role of Resveratrol in Prevention and Control of Cardiovascular Disorders and Cardiovascular Complications Related to COVID-19 Disease: Mode of Action and Approaches Explored to Increase Its Bioavailability

Resveratrol is a phytoalexin produced by many plants as a defense mechanism against stress-inducing conditions. The richest dietary sources of resveratrol are berries and grapes, their juices and wines. Good bioavailability of resveratrol is not reflected in its high biological activity in vivo because of resveratrol isomerization and its poor solubility in aqueous solutions. Proteins, cyclodextrins and nanomaterials have been explored as innovative delivery vehicles for resveratrol to overcome this limitation. Numerous in vitro and in vivo studies demonstrated beneficial effects of resveratrol in cardiovascular diseases (CVD). Main beneficial effects of resveratrol intake are cardioprotective, anti-hypertensive, vasodilatory, anti-diabetic, and improvement of lipid status. As resveratrol can alleviate the numerous factors associated with CVD, it has potential as a functional supplement to reduce COVID-19 illness severity in patients displaying poor prognosis due to cardio-vascular complications. Resveratrol was shown to mitigate the major pathways involved in the pathogenesis of SARS-CoV-2 including regulation of the renin-angiotensin system and expression of angiotensin-converting enzyme 2, stimulation of immune system and downregulation of pro-inflammatory cytokine release. Therefore, several studies already have anticipated potential implementation of resveratrol in COVID-19 treatment. Regular intake of a resveratrol rich diet, or resveratrol-based complementary medicaments, may contribute to a healthier cardio-vascular system, prevention and control of CVD, including COVID-19 disease related complications of CVD.

Resveratrol stereoselectively affected (±)warfarin pharmacokinetics and enhanced the anticoagulation effect

Resveratrol (RVT) has various beneficial bioactivities and popularly used as a dietary supplement. RVT showed inhibitions on CYP1A2/2C9/3A4, breast cancer resistance protein (BCRP), and some conjugated metabolites of RVT also inhibited BCRP. (±)Warfarin, an anticoagulant for cardiovascular disease but with narrow therapeutic window, were substrates of CYP1A2/3A4(R-form), 2C9(S-form) and BCRP. We hypothesized that the concurrent use of RVT might affect the metabolism and excretion of warfarin. This study investigated the effect of RVT on the pharmacokinetics and anticoagulation effect of (±)warfarin. Rats were orally given (±)warfarin (0.2 mg/kg) without and with RVT (100 mg/kg) in a parallel design. The results showed that RVT significantly increased the AUC_0-t of S-warfarin and international normalized ratio. Mechanism studies showed that both RVT and its serum metabolites (RSM) inhibited BCRP-mediated efflux of R- and S-warfarin. Moreover, RSM activated CYP1A2/3A4, but inhibited CYP2C9. In conclusion, concomitant intake of RVT increased the systemic exposure of warfarin and enhanced the anticoagulation effect mainly via inhibitions on BCRP and CYP2C9.

Clinical relevance of St. John's wort drug interactions revisited

The first clinically relevant reports of preparations of St. John's wort (SJW), a herbal medicine with anti‐depressant effects, interacting with other drugs, altering their bioavailability and efficacy, were published about 20 years ago. In 2000, a pharmacokinetic interaction between SJW and cyclosporine caused acute rejection in two heart transplant patients. Since then, subsequent research has shown that SJW altered the pharmacokinetics of drugs such as digoxin, tacrolimus, indinavir, warfarin, alprazolam, simvastatin, or oral contraceptives. These interactions were caused by pregnane‐X‐receptor (PXR) activation. Preparations of SJW are potent activators of PXR and hence inducers of cytochrome P450 enzymes (most importantly CYP3A4) and P‐glycoprotein. The degree of CYP3A4 induction correlates significantly with the hyperforin content in the preparation. Twenty years after the first occurrence of clinically relevant pharmacokinetic drug interactions with SJW, this review revisits the current knowledge of the mechanisms of action and on how pharmacokinetic drug interactions with SJW could be avoided.

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This article is part of a themed section on The Pharmacology of Nutraceuticals. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.6/issuetoc

Pterostilbene supplements carry the risk of drug interaction via inhibition of UDP-glucuronosyltransferases (UGT) 1A9 enzymes

Pterostilbene (PT) is a natural stilbene common in small berries and food supplements, possessing numerous pharmacological activities. However, whether PT can affect the activities of UDP-glucuronosyltransferases (UGT) enzymes remains unclear. The aim of the present study was to investigate the effect of PT on UGT activities and to quantitatively evaluate the food-drug interaction potential due to UGT inhibition. Our data indicated that PT exhibited potent inhibition against HLM, UGT1A6, UGT1A9, UGT2B7, and UGT2B15, moderate inhibition against UGT1A1, UGT1A3, UGT1A8, and UGT2B4, negligible inhibition against UGT1A4, UGT1A7, UGT1A10, and UGT2B17. Further kinetic investigation demonstrated that PT exerted potent noncompetitive inhibition 4-MU glucuronidation by UGT1A9, with IC₅₀ and K_i values of 0.92 μM and 0.52 ± 0.04 μM, respectively. Quantitative prediction study suggested that coadministration of PT supplements at 100 mg/day or higher doses may result in at least a 50% increase in the AUC of drugs predominantly cleared by UGT1A9. Thus, the coadministration of PT supplements and drugs primarily cleared by UGT1A9 may result in potential drug interaction, and precautions should be taken when coadministration of PT supplements and drugs metabolized by UGT1A9.

Effect of Pterostilbene, a Natural Analog of Resveratrol, on the Activity of some Antiepileptic Drugs in the Acute Seizure Tests in Mice

Pterostilbene (PTE), a natural analog of resveratrol, is available both as a diet ingredient and a dietary supplement. The present study was undertaken to assess the effect of PTE on the activity of antiepileptic drugs in the acute seizure tests in mice, i.e., the intravenous pentetrazole (iv PTZ) seizure threshold, maximal electroshock (MES), and 6 Hz-induced psychomotor seizure tests. Our study revealed that PTE enhanced the anticonvulsant effect of clonazepam but did not change the activity of tiagabine in the iv PTZ test. In the MES test, PTE increased the effect of carbamazepine but did not affect the protective properties of topiramate, while in the 6-Hz test, we noted a significant enhancement of the activity of oxcarbazepine, but there were no changes in the activity of valproate. Interactions of PTE with carbamazepine and oxcarbazepine were pharmacokinetic, which was determined by the increase of concentration of these antiepileptic drugs both in the serum and brain. In contrast, interactions between PTE and clonazepam were pharmacodynamic since there were no changes in the concentration of clonazepam. Combined treatment with carbamazepine and PTE significantly attenuated muscular strength (estimated in the grip strength test) but did not change motor coordination (assessed in the chimney test) in mice. Other studied antiepileptic drugs and their combinations with PTE did not change these parameters. Further studies are required to evaluate the influence of PTE on the activity of anticonvulsant drugs to estimate the safety of using PTE by patients with epilepsy.

Stilbene compound trans-3,4,5,4´-tetramethoxystilbene, a potential anticancer drug, regulates constitutive androstane receptor (Car) target genes, but does not possess proliferative activity in mouse liver

The constitutive androstane receptor(CAR) activation is connected with mitogenic effects leading to liver hyperplasia and tumorigenesis in rodents. CAR activators, including phenobarbital, are considered rodent non-genotoxic carcinogens. Recently, trans-3,4,5,4´-tetramethoxystilbene(TMS), a potential anticancer drug (DMU-212), have been shown to alleviate N-nitrosodiethylamine/phenobarbital-induced liver carcinogenesis. We studied whether TMS inhibits mouse Car to protect from the PB-induced tumorigenesis. Unexpectedly, we identified TMS as a murine CAR agonist in reporter gene experiments, in mouse hepatocytes, and in C57BL/6 mice in vivo. TMS up-regulated Car target genes Cyp2b10, Cyp2c29 and Cyp2c55 mRNAs, but down-regulated expression of genes involved in gluconeogenesis and lipogenesis. TMS did not change or down-regulate genes involved in liver proliferation or apoptosis such as Mki67, Foxm1, Myc, Mcl1, Pcna, Bcl2, or Mdm2, which were up-regulated by another Car ligand TCPOBOP. TMS did not increase liver weight and had no significant effect on Ki67 and Pcna labeling indices in mouse liver in vivo. In murine hepatic AML12 cells, we confirmed a Car-independent proapoptotic effect of TMS. We conclude that TMS is a Car ligand with limited effects on hepatocyte proliferation, likely due to promoting apoptosis in mouse hepatic cells, while controlling Car target genes involved in xenobiotic and endobiotic metabolism.

Marine Ligands of the Pregnane X Receptor (PXR): An Overview

Pregnane X Receptor (PXR) is a ligand-activated transcription factor which binds many structurally different molecules. The receptor is able to regulate the expression of a wide array of genes and is involved in cancer and different key physiological processes such as the metabolism of drugs/xenobiotics and endogenous compounds including lipids and carbohydrates, and inflammation. Algae, sponges, sea squirts, and other marine organisms are some of the species from which structurally new molecules have been isolated that have been subsequently identified in recent decades as ligands for PXR. The therapeutic potential of these natural compounds is promising in different areas and has recently resulted in the registration of trabectedin by the FDA as a novel antineoplastic drug. Apart from being potentially novel drugs, these compounds can also serve as models for the development of new molecules with improved activity. The aim of this review is to succinctly summarize the currently known natural molecules isolated from marine organisms with a proven ability to interact with PXR.

High-content analysis of constitutive androstane receptor (CAR) translocation identifies mosapride citrate as a CAR agonist that represses gluconeogenesis

The constitutive androstane receptor (CAR) plays an important role in hepatic drug metabolism and detoxification but has recently been projected as a potential drug target for metabolic disorders due to its repression of lipogenesis and gluconeogenesis. Thus, identification of physiologically-relevant CAR modulators has garnered significant interest. Here, we adapted the previously characterized human CAR (hCAR) nuclear translocation assay in human primary hepatocytes (HPH) to a high-content format and screened an FDA-approved drug library containing 978 compounds. Comparison of hCAR nuclear translocation results with the Tox21 hCAR luciferase reporter assay database in 643 shared compounds revealed significant overlap between these two assays, with approximately half of hCAR agonists also mediating nuclear translocation. Further validation of these compounds in HPH and/or using published data from literature demonstrated that hCAR translocation exhibits a higher correlation with the induction of hCAR target genes, such as CYP2B6, than the luciferase assay. In addition, some CAR antagonists which repress CYP2B6 mRNA expression in HPH, such as sorafenib, rimonabant, and CINPA1, were found to translocate hCAR to the nucleus of HPH. Notably, both the translocation assay and the luciferase assay identified mosapride citrate (MOS), a gastroprokinetic agent that is known to reduce fasting blood glucose levels in humans, as a novel hCAR activator. Further studies with MOS in HPH uncovered that MOS can repress the expression of gluconeogenic genes and decrease glucose output from hepatocytes, providing a previously unidentified liver-specific mechanism by which MOS modulates blood glucose levels.