Clinically Relevant Herb-Drug Interactions: A 30-Year Historical Assessment.

The Dietary Supplement Health and Education Act, a legislative measure ushering in a novel class of complementary healthcare products known as dietary supplements, will mark its 30th anniversary in October 2024. Over this 30-year period, dietary supplement usage evolved from a few hundred products made up mostly of vitamins, minerals, and select botanical extracts to more than 75,000 single- and multi-ingredient products that are now regular staples in the American healthcare system and used by half of all U.S. consumers. One of the fastest-growing segments of the dietary supplement market during this 3-decade interval has been those products formulated with botanical extracts. Coincident with the growing popularity of botanical dietary supplements (BDS) has been their concomitant ingestion with conventional prescription medications. BDS are complex mixtures of phytochemicals oftentimes exhibiting complex pharmacology. Formulated as concentrated phytochemical extracts, BDS are vehicles for a host of plant secondary metabolites rarely encountered in the typical diet. When taken with prescription drugs, BDS may give rise to clinically significant herb-drug interactions (HDI). Pharmacodynamic HDI describe interactions between phytochemicals and conventional medications at the drug receptor level, while pharmacokinetic HDI stem from phytochemical-mediated induction and/or inhibition of human drug metabolizing enzymes and/or transporters. This review summarizes BDS identified over the last 30 years that pose clinically relevant HDI and whose mechanisms are either pharmacodynamically or pharmacokinetically mediated.

Development of a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for characterizing pomegranate extract pharmacokinetics in humans.

Pomegranate extracts standardized to punicalagins are a rich source of ellagitannins including ellagic acid (EA). Recent evidence suggests that gut microbiota-derived urolithin (Uro) metabolites of ellagitannins are pharmacologically active. Studies have evaluated the pharmacokinetics of EA, however, little is known about the disposition of urolithin metabolites (urolithin A (UA) and B (UB)). To address this gap, we developed and applied a novel ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) assay for the characterization of EA and Uro oral pharmacokinetics in humans. Subjects (10/cohort) received a single oral dose (250 or 1000 mg) of pomegranate extract (Pomella® extract) standardized to contain not less than 30 % punicalagins, < 5 % EA, and not less than 50 % polyphenols. Plasma samples, collected over 48 h, were treated with ß-glucuronidase and sulfatase to permit comparison between unconjugated and conjugated forms of EA, UA and UB. EA and urolithins were separated by gradient elution (acetonitrile/water, 0.1 % formic acid) using a C18 column connected to a triple quadrupole mass spectrometer operating in the negative mode. Conjugated EA exposure was ∼5-8-fold higher than unconjugated EA for both dose groups. Conjugated UA was readily detectable beginning ∼8 h post-dosing, however, unconjugated UA was detectable in only a few subjects. Neither form of UB was detected. Together these data indicate EA is rapidly absorbed and conjugated following oral administration of Pomella® extract. Moreover, UA's delayed appearance in the blood, primarily in the conjugated form, is consistent with gut microbiota-mediated metabolism of EA to UA, which is then rapidly converted to its conjugated form.

Evaluation of the Herb-Drug Interaction (HDI) Potential of Zingiber officinale and Its Major Phytoconstituents.

Ginger is currently one of the most popular herbs commonly added to diverse foods, beverages, and dietary supplements. We evaluated the ability of a well-characterized ginger extract, and several of its phytoconstituents, to activate select nuclear receptors as well as modulate the activity of various cytochrome P450s and ATP-binding cassette (ABC) transporters because phytochemical-mediated modulation of these proteins underlies many clinically relevant herb-drug interactions (HDI). Our results revealed ginger extract activated the aryl hydrocarbon receptor (AhR) in AhR-reporter cells and pregnane X receptor (PXR) in intestinal and hepatic cells. Among the phytochemicals investigated, (S)-6-gingerol, dehydro-6-gingerdione, and (6S,8S)-6-gingerdiol activated AhR, while 6-shogaol, 6-paradol, and dehydro-6-gingerdione activated PXR. Enzyme assays showed that ginger extract and its phytochemicals dramatically inhibited the catalytic activity of CYP3A4, 2C9, 1A2, and 2B6, and efflux transport capabilities of P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP). Dissolution studies with ginger extract conducted in biorelevant simulated intestinal fluid yielded (S)-6-gingerol and 6-shogaol concentrations that could conceivably exceed cytochrome P450 (CYP) IC50 values when consumed in recommended doses. In summary, overconsumption of ginger may disturb the normal homeostasis of CYPs and ABC transporters, which in turn, may elevate the risk for HDIs when consumed concomitantly with conventional medications.

Screening of medicinal plants for possible herb-drug interactions through modulating nuclear receptors, drug-metabolizing enzymes and transporters.

ETHNOPHARMACOLOGICAL RELEVANCE: The last three decades have witnessed a surge in popularity and consumption of herbal products. An unintended consequence of such popularity is that chronic consumption of these products can often modulate the functions of various proteins involved in drug disposition and may, in turn, impose risks for herb-drug interactions (HDIs), leading to serious adverse health outcomes. Identifying plants that may give rise to clinically relevant HDIs is essential, and proactive dissemination of such research outcomes is necessary for researchers, clinicians, and average consumers. AIM OF THE STUDY: The main objective of this study was to evaluate the HDI potential of plants commonly used as ingredients in many herbal products, including BDS. MATERIALS AND METHODS: The dried material of 123 plants selected from the NCNPR repository was extracted with 95% ethanol. The extracts were screened for agonistic effects on nuclear receptors (PXR and AhR) by reporter gene assays in PXR-transfected HepG2 and AhR-reporter cells. For cytochrome P450 enzyme (CYP) inhibition studies, CYP450 baculosomes were incubated with enzyme-specific probe substrates by varying concentrations of extracts. The inhibitory effect on the efflux transporter P-glycoprotein (P-gp) was investigated via rhodamine (Rh-123) uptake assay in P-gp overexpressing MDR1-MDCK cells. RESULTS: Out of 123 plants, 16 increased transcriptional activity of human PXR up to 4 to 7-fold at 60 µg/mL, while 18 plants were able to increase AhR activity up to 10 to 40-fold at 30 µg/mL. Thirteen plants inhibited the activity of CYP3A4, while 10 plants inhibited CYP1A2 activity with IC50 values in the range of 1.3-10 µg/mL. Eighteen plants (at 50 µg/mL) increased intracellular accumulation of Rh-123 (>150%) in MDR1-MDCK cells. Additionally, other plants tested in this study were able to activate PXR, AhR, or both to lesser extents, and several inhibited the catalytic activity of CYPs at higher concentrations (IC50 >10 µg/mL). CONCLUSIONS: The results indicate that prolonged or excessive consumption of herbal preparations rich in such plants (presented in Figs. 1a, 2a, 3a, 4a, and 5a) may pose a risk for CYP- and P-gp-mediated HDIs, leading to unwanted side effects due to the altered pharmacokinetics of concomitantly ingested medications.

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

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

Hepatotoxicity due to herbal dietary supplements: Past, present and the future.

Dietary supplements (DS) constitute a widely used group of products comprising vitamin, mineral, and botanical extract formulations. DS of botanical or herbal origins (HDS) comprise nearly 30% of all DS and are presented on the market either as single plant extracts or multi-extract-containing products. Despite generally safe toxicological profiles of most products currently present on the market, rising cases of liver injury caused by HDS - mostly by multi-ingredient and adulterated products - are of particular concern. Here we discuss the most prominent historical cases of HDS-induced hepatotoxicty - from Ephedra to Hydroxycut and OxyELITE Pro-NF, as well as products with suspected hepatotoxicity that are either currently on or are entering the market. We further provide discussion on overcoming the existing challenges with HDS-linked hepatotoxicity by introduction of advanced in silico, in vitro, in vivo, and microphysiological system approaches to address the matter of safety of those products before they reach the market.

Safety and Pharmacokinetics of Intranasally Administered Heparin.

PURPOSE: Intranasally administered unfractionated heparin (UFH) and other sulfated polysaccharides are potential prophylactics for COVID-19. The purpose of this research was to measure the safety and pharmacokinetics of clearance of intranasally administered UFH solution from the nasal cavity. METHODS: Double-blinded daily intranasal dosing in C57Bl6 mice with four doses (60 ng to 60 µg) of UFH was carried out for fourteen consecutive days, with both blood coagulation measurements and subject adverse event monitoring. The pharmacokinetics of fluorescent-labeled UFH clearance from the nasal cavity were measured in mice by in vivo imaging. Intranasal UFH at 2000 U/day solution with nasal spray device was tested for safety in a small number of healthy human subjects. RESULTS: UFH showed no evidence of toxicity in mice at any dose measured. No significant changes were observed in activated partial thromboplastin time (aPTT), platelet count, or frequency of minor irritant events over vehicle-only control. Human subjects showed no significant changes in aPTT time, international normalized ratio (INR), or platelet count over baseline measurements. No serious adverse events were observed. In vivo imaging in a mouse model showed a single phase clearance of UFH from the nasal cavity. After 12 h, 3.2% of the administered UFH remained in the nasal cavity, decaying to background levels by 48 h. CONCLUSIONS: UFH showed no toxic effects for extended daily intranasal dosing in mice as well as humans. The clearance kinetics of intranasal heparin solution from the nasal cavity indicates potentially protective levels for up to 12 h after dosing.

Safety and Pharmacokinetics of Intranasally Administered Heparin.

PURPOSE: Intranasally administered unfractionated heparin (UFH) and other sulfated polysaccharides are potential prophylactics for COVID-19. The purpose of this research was to measure the safety and pharmacokinetics of clearance of intranasally administered UFH solution from the nasal cavity. METHODS: Double-blinded daily intranasal dosing in C57Bl6 mice with four doses (60 ng to 60 µg) of UFH was carried out for fourteen consecutive days, with both blood coagulation measurements and subject adverse event monitoring. The pharmacokinetics of fluorescent-labeled UFH clearance from the nasal cavity were measured in mice by in vivo imaging. Intranasal UFH at 2000 U/day solution with nasal spray device was tested for safety in a small number of healthy human subjects. RESULTS: UFH showed no evidence of toxicity in mice at any dose measured. No significant changes were observed in activated partial thromboplastin time (aPTT), platelet count, or frequency of minor irritant events over vehicle-only control. Human subjects showed no significant changes in aPTT time, international normalized ratio (INR), or platelet count over baseline measurements. No serious adverse events were observed. In vivo imaging in a mouse model showed a single phase clearance of UFH from the nasal cavity. After 12 hours, 3.2% of the administered UFH remained in the nasal cavity, decaying to background levels by 48 hours. CONCLUSIONS: UFH showed no toxic effects for extended daily intranasal dosing in mice as well as humans. The clearance kinetics of intranasal heparin solution from the nasal cavity indicates potentially protective levels for up to 12 hours after dosing.

Bulbine natalensis (currently Bulbine latifolia) and select bulbine knipholones modulate the activity of AhR, CYP1A2, CYP2B6, and P-gp.

Bulbine natalensis, an emerging medicinal herb on the global market with androgenic properties, is often formulated in dietary supplements that promote perceived sexual enhancement. However, to date, comprehensive safety studies of B. natalensis are lacking, particularly those related to its herb-drug interaction potential. The purpose of this study was to assess the inductive and inhibitory effects of extracts and pure compounds of B. natalensis on human cytochrome P-450 isozymes in vitro. Our findings demonstrated that both water and methanolic extracts of B. natalensis as well as knipholone, bulbine-knipholone, and 6'-O-methylknipholone dose-dependently increased mRNA expression encoded by CYP2B6, CYP1A2, and ABCB1 genes. Functional analyses showed that water (60 to 2.20 µg/mL) and methanolic (30 to 3.75 µg/mL) extracts and knipholones (10 to 0.33 µM) increased CYP2B6 and CYP1A2 activity in a dose-dependent manner. Additionally, water extract (60 µg/mL), methanolic extract (30 µg/mL), and knipholone (10 µM) caused activation of the aryl hydrocarbon receptor up to 11.1 ± 0.7, 8.9 ± 0.6, and 7.1 ± 2.0-fold, respectively. Furthermore, inhibition studies revealed that methanolic extract attenuated the activity of metabolically active CYP1A2 (IC50, 22.6 ± 0.4 µg/mL) and CYP2B6 (IC50, 34.2 ± 6.6 µg/mL) proteins, whereas water extracts had no inhibitory effect on either isoform. These findings suggest that chronic consumption of B. natalensis may affect normal homeostasis of select CYPs with subsequent risks for HDIs when concomitantly ingested with conventional medications that are substrates of CYP2B6 and CYP1A2. However, more in-depth translational studies are required to validate our current findings and their clinical relevance.

Designing a Clinical Study With Dietary Supplements: It's All in the Details.

A successful randomized clinical trial of the effect of dietary supplements on a chosen endpoint begins with developing supporting data in preclinical studies while paying attention to easily overlooked details when planning the related clinical trial. In this perspective, we draw on our experience studying the effect of an ethanolic extract from Artemisia dracunculus L. (termed PMI-5011) on glucose homeostasis as a potential therapeutic option in providing resilience to metabolic syndrome (MetS). Decisions on experimental design related to issues ranging from choice of mouse model to dosing levels and route of administration in the preclinical studies will be discussed in terms of translation to the eventual human studies. The more complex considerations in planning the clinical studies present different challenges as these studies progress from testing the safety of the dietary supplement to assessing the effect of the dietary supplement on a predetermined clinical outcome. From the vantage point of hindsight, we will outline potential pitfalls when translating preclinical studies to clinical studies and point out details to address when designing clinical studies of dietary supplements.

Analytical Challenges and Metrological Approaches to Ensuring Dietary Supplement Quality: International Perspectives.

The increased utilization of metrology resources and expanded application of its' approaches in the development of internationally agreed upon measurements can lay the basis for regulatory harmonization, support reproducible research, and advance scientific understanding, especially of dietary supplements and herbal medicines. Yet, metrology is often underappreciated and underutilized in dealing with the many challenges presented by these chemically complex preparations. This article discusses the utility of applying rigorous analytical techniques and adopting metrological principles more widely in studying dietary supplement products and ingredients, particularly medicinal plants and other botanicals. An assessment of current and emerging dietary supplement characterization methods is provided, including targeted and non-targeted techniques, as well as data analysis and evaluation approaches, with a focus on chemometrics, toxicity, dosage form performance, and data management. Quality assessment, statistical methods, and optimized methods for data management are also discussed. Case studies provide examples of applying metrological principles in thorough analytical characterization of supplement composition to clarify their health effects. A new frontier for metrology in dietary supplement science is described, including opportunities to improve methods for analysis and data management, development of relevant standards and good practices, and communication of these developments to researchers and analysts, as well as to regulatory and policy decision makers in the public and private sectors. The promotion of closer interactions between analytical, clinical, and pharmaceutical scientists who are involved in research and product development with metrologists who develop standards and methodological guidelines is critical to advance research on dietary supplement characterization and health effects.

Modulation of CYP3A4 and CYP2C9 activity by Bulbine natalensis and its constituents: An assessment of HDI risk of B. natalensis containing supplements.

BACKGROUND: Bulbine natalensis is an African-folk medicinal plant used as a dietary supplement for enhancing sexual function and muscle strength in males by presumably boosting testosterone levels, but no scientific information is available about the possible herb-drug interaction (HDI) risk when bulbine-containing supplements are concomitantly taken with prescription drugs. PURPOSE: This study was aimed to investigate the HDI potential of B. natalensis in terms of the pregnane X receptor (PXR)-mediated induction of major drug-metabolizing cytochrome P450 enzyme isoforms (i.e., CYP3A4 and CYP2C9) as well as inhibition of their catalytic activity. RESULTS: We found that a methanolic extract of B. natalensis activated PXR (EC50 6.2 ± 0.6 µg/ml) in HepG2 cells resulting in increased mRNA expression of CYP3A4 (2.40 ± 0.01 fold) and CYP2C9 (3.37 ± 0.3 fold) at 30 µg/ml which was reflected in increased activites of the two enzymes. Among the constituents of B. natalensis, knipholone was the most potent PXR activator (EC50 0.3 ± 0.1 µM) followed by bulbine-knipholone (EC50 2.0 ± 0.5 µM), and 6'-methylknipholone (EC50 4.0 ± 0.5 µM). Knipholone was also the most effective in increasing the expression of CYP3A4 (8.47 ± 2.5 fold) and CYP2C9 (2.64 ± 0.3 fold) at 10 µM. Docking studies further confirmed the unique structural features associated with knipholones for their superior inductive potentials in the activation of PXR compared to other anthraquinones. In a CYP inhibition assay, the methanolic extract as well as the anthraquinones strongly inhibited the catalytic activity of CYP2C9 while, inhibition of CYP3A4 was weak. CONCLUSIONS: These results suggest that consumption of B. natalensis may pose a potential risk for HDI if taken with conventional medications that are substrates of CYP3A4 and CYP2C9 and may contribute to unanticipated adverse reactions or therapeutic failures. Further studies are warranted to validate these findings and establish their clinical relevancy.

Safety and Molecular-Toxicological Implications of Cannabidiol-Rich Cannabis Extract and Methylsulfonylmethane Co-Administration.

Cannabidiol (CBD) is a biologically active, non-psychotropic component of Cannabis sativa whose popularity has grown exponentially in recent years. Besides a wealth of potential health benefits, ingestion of CBD poses risks for a number of side effects, of which hepatotoxicity and CBD/herb-drug interactions are of particular concern. Here, we investigated the interaction potential between the cannabidiol-rich cannabis extract (CRCE) and methylsulfonylmethane (MSM), a popular dietary supplement, in the mouse model. For this purpose, 8-week-old male C57BL6/J mice received MSM-containing water (80 mg/100 mL) ad libitum for 17 days. During the last three days of treatment, mice received three doses of CRCE administered in sesame oil via oral gavage (123 mg/kg/day). Administration of MSM alone did not result in any evidence of liver toxicity and did not induce expression of mouse cytochrome P450 (CYP) enzymes. Administration of CRCE did produce significant (p < 0.05) increases in Cyp1a2, Cyp2b10, Cyp2c29, Cyp3a4, Cyp3a11, Cyp2c65, and Cyp2c66 messenger RNA, however, this effect was not amplified by MSM/CRCE co-treatment. Similarly, no evidence of liver toxicity was observed in MSM/CRCE dosed mice. In conclusion, short-term MSM/CRCE co-administration did not demonstrate any evidence of hepatotoxicity in the mouse model.

Cannabidiol (CBD) in Dietary Supplements: Perspectives on Science, Safety, and Potential Regulatory Approaches.

The proliferation in the last few years of cannabidiol (CBD)-containing products in the U.S. markets has been greatly accelerated by changes in the regulatory environment, and by perceptions of their health benefits and presumed safety. The result has been aggressive marketing of many types of products, some of dubious quality, making or implying drug-type claims. The recent approval by the U.S. Food and Drug Administration (FDA) of CBD in the form of Epidiolex®, further complicates the regulatory picture. In addition, a number of studies suggest that, at least at high doses, there may be serious adverse effects or drug interactions associated with CBD. At present, CBD-containing products do not meet the strict definition of dietary supplements, but the FDA is continuing to consider some framework under which they might be allowed. Meanwhile, FDA has adopted a "risk-based" enforcement policy. Possible approaches to a new framework for regulation of CBD products as dietary supplements are discussed here, including expanded research emphasis, a robust corporate stewardship program, and a rigorous adverse event reporting program.

Medical Foods-A Closer Look at the Menu: A Brief Review and Commentary.

The notion of a medical food-a foodstuff that, by definition, must be obtained and used while under medical supervision, and regulated by the US Food and Drug Administration, is a source of considerable confusion to the lay public as well as many-if not most-in the health professions community. Such restrictions are more often associated with pharmaceutical agents or medical devices. Additionally, specific regulatory aspects of medical foods are overseen by the US Food and Drug Administration, and these specifics appear to overlap with other foods and dietary supplements in terms of requirements and allowances. Furthermore, these requirements and allowances have changed over time and are likely to continue to evolve via federal regulatory action, or the introduction of newer formulations that defy current categorization. The present review attempts to bring some clarity to the definition of medical foods, to parse out the differences from related products, and to review the terminology surrounding medical foods, other foods, and dietary supplements.l.

Content versus Label Claims in Cannabidiol (CBD)-Containing Products Obtained from Commercial Outlets in the State of Mississippi.

Products containing cannabidiol (CBD) are now available throughout the United States, but their quality is oftentimes questionable. The CBD and Δ9-tetrahydrocannabinol (THC) content of 25 commercially available hemp oil products, obtained throughout the state of Mississippi, was determined via gas chromatography/flame ionization detection (GC/FID). These products were also analyzed for the presence of synthetic cannabinoids using full scan gas chromatography/mass spectrometry (GC/MS). Analytical findings were compared to label claims for CBD content. Product label claims for CBD ranged from no claim to 500 mg per serving; however, marked variability was observed between actual CBD content and claimed quantities. Of the 25 products, only three were within ±20% of label claim. Fifteen were well below the stated claim for CBD; two exceed claims in excess of 50%; and 5 made no claims. In addition, THC content for three products exceeded the 0.3% legal limit. Furthermore, four products-primarily marketed for vaping-were adulterated with synthetic cannabinoids. From this small, but diverse, sampling of hemp-derived merchandise, it appears that most product label claims do not accurately reflect actual CBD content and are fraudulent in that regard. Moreover, products that exceed legal THC levels may jeopardize a consumer's employment status (i.e. failed "drug test"), while those adulterated with synthetic cannabinoids may subject them to serious adverse health effects. These findings argue strongly for further development of current good manufacturing practices for CBD-containing products and their stringent enforcement.

Potential Probiotic or Trigger of Gut Inflammation - The Janus-Faced Nature of Cannabidiol-Rich Cannabis Extract.

Cannabidiol (CBD) is the major non-psychotropic phytocannabinoid present in Cannabis sativa. In 2018, Congress designated certain C. sativa plant material as "hemp," thus removing it from the DEA's list of controlled substances. As a result, CBD-containing hemp extracts and other CBD products are now widely available and heavily marketed, yet their FDA regulatory status is still hotly debated. The goal of this study was to investigate the effects of a cannabidiol-rich cannabis extract (CRCE) on the gut microbiome and associated histomorphological and molecular changes in the mouse gut mucosa. Male C57BL6/J mice were gavaged with either 0, 61.5, 184.5, or 615 mg/kg/bw of CRCE in sesame oil for 2 weeks (Mon-Fri). Substantial CRCE-induced increases in the relative abundance of A. muciniphila, a bacterial species currently accepted as probiotic, was observed in fecal samples at all doses. This was paralleled by decreases in the relative abundance of other gut bacterial species. Coincident with the observed changes in gut ecology were multiple pro-inflammatory responses, including increased expression of cytokines and chemokines-Il1ß, Cxcl1, and Cxcl2 in the colon tissue. Furthermore, dramatic increases in the relative abundance of A. muciniphila significantly decreased expression of Muc2-a gene intimately associated with gut integrity. Taken together, these findings raise concerns about the safety of long-term CBD usage and underline the need for additional well-designed studies into its tolerability and efficacy.

United States Pharmacopeia (USP) comprehensive review of the hepatotoxicity of green tea extracts.

As part of the United States Pharmacopeia's ongoing review of dietary supplement safety data, a new comprehensive systematic review on green tea extracts (GTE) has been completed. GTEs may contain hepatotoxic solvent residues, pesticide residues, pyrrolizidine alkaloids and elemental impurities, but no evidence of their involvement in GTE-induced liver injury was found during this review. GTE catechin profiles vary significantly with manufacturing processes. Animal and human data indicate that repeated oral administration of bolus doses of GTE during fasting significantly increases bioavailability of catechins, specifically EGCG, possibly involving saturation of first-pass elimination mechanisms. Toxicological studies show a hepatocellular pattern of liver injury. Published adverse event case reports associate hepatotoxicity with EGCG intake amounts from 140 mg to ∼1000 mg/day and substantial inter-individual variability in susceptibility, possibly due to genetic factors. Based on these findings, USP included a cautionary labeling requirement in its Powdered Decaffeinated Green Tea Extract monograph that reads as follows: "Do not take on an empty stomach. Take with food. Do not use if you have a liver problem and discontinue use and consult a healthcare practitioner if you develop symptoms of liver trouble, such as abdominal pain, dark urine, or jaundice (yellowing of the skin or eyes)."

Effect of Aromatase Inhibition (Exemestane) on Urine Concentration of Osteoprotegerin in Healthy Postmenopausal Women.

This pilot study examined how exemestane (an aromatase inhibitor [AI]) affected osteoprotegerin (OPG) urine concentrations in postmenopausal women. Exemestane (25 mg, single dose) was given to 14 disease-free women past menopause in this nonrandomized, open-label study. Before dosing, urine specimens were gathered. Three days later, these women returned to provide urine specimens for pharmacokinetic (measurement of major parent drug and enzymatic product) and pharmacodynamic (profiling of OPG) analysis. Urine concentrations of the major parent drug (exemestane) and enzymatic product (17-hydroexemestane) were quantified using liquid chromatography-tandem mass spectrometry. An analyst software package was used for data processing. Following the manufacturer's guidelines, OPG urine concentrations were quantified using a human osteoprotegerin TNFRSF11b ELISA kit from Sigma-Aldrich. A microplate reader helped to carry out OPG data analysis and processing. Our results highlight that OPG urine concentrations were decreased 3 days after drug dosage (mean predosage OPG concentration, 61.4 ± 24.1 pg/mL; vs mean postdosage OPG concentration, 45.7 ± 22.1 pg/mL; P = .02, Wilcoxon rank test). Among the 14 volunteers enrolled in the study, 4 subjects had an increase of less than 1-fold, and the rest showed an average of a 2-fold decrease in OPG concentration (range, 1.1-5.4; standard deviation, 1.3) after exemestane administration. There was no association between fold decrease in OPG urine concentration and the pharmacokinetics of the major parent drug (exemestane) and its enzymatic product (17-hydroexemestane). We concluded that one of the off-target pharmacological effects of AIs (eg ,exemestane) may result in the reduction of osteoprotegerin.

The Potential for Pharmacokinetic Interactions Between Cannabis Products and Conventional Medications.

PURPOSE: Increased cannabis use and recent drug approvals pose new challenges for avoiding drug interactions between cannabis products and conventional medications. This review aims to identify drug-metabolizing enzymes and drug transporters that are affected by concurrent cannabis use and, conversely, those co-prescribed medications that may alter the exposure to one or more cannabinoids. METHODS: A systematic literature search was conducted utilizing the Google Scholar search engine and MEDLINE (PubMed) database through March 2019. All articles describing in vitro or clinical studies of cannabis drug interaction potential were retrieved for review. Additional articles of interest were obtained through cross-referencing of published bibliographies. FINDINGS: After comparing the in vitro inhibition parameters to physiologically achievable cannabinoid concentrations, it was concluded that CYP2C9, CYP1A1/2, and CYP1B1 are likely to be inhibited by all 3 major cannabinoids Δ-tetrahydrocannabinol (THC), cannabidiol (CBD), and cannabinol (CBN). The isoforms CYP2D6, CYP2C19, CYP2B6, and CYP2J2 are inhibited by THC and CBD. CYP3A4/5/7 is potentially inhibited by CBD. Δ-Tetrahydrocannabinol also activates CYP2C9 and induces CYP1A1. For non-CYP drug-metabolizing enzymes, UGT1A9 is inhibited by CBD and CBN, whereas UGT2B7 is inhibited by CBD but activated by CBN. Carboxylesterase 1 (CES1) is potentially inhibited by THC and CBD. Clinical studies suggest inhibition of CYP2C19 by CBD, inhibition of CYP2C9 by various cannabis products, and induction of CYP1A2 through cannabis smoking. Evidence of CBD inhibition of UGTs and CES1 has been shown in some studies, but the data are limited at present. We did not identify any clinical studies suggesting an influence of cannabinoids on drug transporters, and in vitro results suggest that a clinical interaction is unlikely. CONCLUSIONS: Medications that are prominent substrates for CYP2C19, CYP2C9, and CYP1A2 may be particularly at risk of altered disposition by concomitant use of cannabis or 1 or more of its constituents. Caution should also be given when coadministered drugs are metabolized by UGT or CES1, on which subject the information remains limited and further investigation is warranted. Conversely, conventional drugs with strong inhibitory or inductive effects on CYP3A4 are expected to affect CBD disposition.