Pharmacokinetic Interactions of a Hop Dietary Supplement with Drug Metabolism in Perimenopausal and Postmenopausal Women

Pharmacokinetic and pharmacodynamic herb-drug interactions-part I. Herbal medicines of the central nervous system

Unlike conventional drug substances, herbal medicines are composed of a complex of biologically active compounds. Therefore, the potential occurrence of herb-drug interactions is even more probable than for drug-drug interactions. Interactions can occur on both the pharmacokinetic and pharmacodynamic level. Herbal medicines may affect the resulting efficacy of the concomitantly used (synthetic) drugs, mainly on the pharmacokinetic level, by changing their absorption, distribution, metabolism, and excretion. Studies on the pharmacodynamic interactions of herbal medicines and conventional drugs are still very limited. This interaction level is related to the mechanism of action of different plant constituents. Herb-drug interactions can cause changes in drug levels and activities and lead to therapeutic failure and/or side effects (sometimes toxicities, even fatal). This review aims to provide a summary of recent information on the potential drug interactions involving commonly used herbal medicines that affect the central nervous system (Camellia, Valeriana, Ginkgo, Hypericum, Humulus, Cannabis) and conventional drugs. The survey databases were used to identify primary scientific publications, case reports, and secondary databases on interactions were used later on as well. Search keywords were based on plant names (botanical genera), officinal herbal drugs, herbal drug preparations, herbal drug extracts.

The Pharmacokinetics of Individual Conjugated Xanthohumol Metabolites Show Efficient Glucuronidation and Higher Bioavailability of Micellar than Native Xanthohumol in a Randomized, Double-Blind, Crossover Trial in Healthy Humans

SCOPE

Prenylated chalcones and flavonoids are found in many plants and are believed to have beneficial effects on health when consumed. Xanthohumol is present in beer and likely the most consumed prenylated chalcone, but poorly absorbed and rapidly metabolized and excreted, thus limiting its bioavailability. Micellar formulations of phytochemicals have been shown to improve bioavailability.

METHODS AND RESULTS

In a randomized, double-blind, crossover trial with five healthy (three males and two females) volunteers, a single dose of 43 mg was orally administered as a native or micellar formulation. The major human xanthohumol metabolites are quantified in plasma. Unmetabolized free xanthohumol makes 1% or less of total plasma xanthohumol. The area under the plasma concentration-time curve of xanthohumol-7-O-glucuronide following the ingestion of the micellular formulation is 5-fold higher and its maximum plasma concentration is more than 20-fold higher compared to native xanthohumol.

CONCLUSION

Metabolism of orally ingested xanthohumol is complex and efficiently converts the parent compound to predominantly glucuronic acid and to a lesser extent sulfate conjugates. The oral bioavailability of micellar xanthohumol is superior to native xanthohumol, making it a useful delivery form for future human trials.

Stepwise Targeted Matching Strategy for Comprehensive Profiling of Xanthohumol Metabolites In Vivo and In Vitro Using UHPLC-Q-Exactive Orbitrap Mass Spectrometer

Xanthohumol (XN), a natural prenylated flavonoid extracted and isolated from the hop plant (Humulus lupulus), possesses diverse pharmacological activities. Although the metabolites of XN have been investigated in the previous study, a comprehensive metabolic profile has been insufficient in vivo or in vitro until now. The current study was aimed at systematically elucidating the metabolic pathways of XN after oral administration to rats. Herein, a UHPLC-Q-Exactive Orbitrap MS was adopted for the potential metabolites detection. A stepwise targeted matching strategy for the overall identification of XN metabolites was proposed. A metabolic net (53 metabolites included) on XN in vivo and in vitro, as well as the metabolic profile investigation, were designed, preferably characterizing XN metabolites in rat plasma, urine, liver, liver microsomes, and feces. On the basis of a stepwise targeted matching strategy, the net showed that major in vivo metabolic pathways of XN in rats include glucuronidation, sulfation, methylation, demethylation, hydrogenation, dehydrogenation, hydroxylation, and so on. The proposed metabolic pathways in this research will provide essential data for further pharmaceutical studies of prenylated flavonoids and lay the foundation for further toxicity and safety studies.

The Reason Beer Makes You Pee and Why You Should Abstain before Orthopedic Surgery

Hydration practices in the view of hip, knee, or spine surgery instruct patients to avoid caffeinated drinks, alcoholic beverages, and sugar-sweetened drinks because they adversely impact body fluid homeostasis. However, some patients might be inclined to not include beer among the prohibited beverages because of its low alcohol content and conflicting evidence about its rehydrating effects. The author of this opinion article discusses the shreds of evidence that establish beer as a drink to avoid prior to orthopedic surgery.

Pharmacokinetic Interactions of a Licorice Dietary Supplement with Cytochrome P450 Enzymes in Female Participants

Licorice, the roots and rhizomes of Glycyrrhiza glabra L., has been used as a medicinal herb, herbal adjuvant, and flavoring agent since ancient times. Recently, licorice extracts have become popular as dietary supplements used by females to alleviate menopausal symptoms. Exposure to licorice products containing high levels of glycyrrhizic acid can cause hypokalemia, but independent from this effect, preclinical data indicate that licorice can inhibit certain cytochrome P450 (P450) enzymes. To evaluate whether clinically relevant pharmacokinetic interactions of licorice with P450 enzymes exist, a phase 1 clinical investigation was carried out using a licorice extract depleted in glycyrrhizic acid (content <1%) and a cocktail containing caffeine, tolbutamide, alprazolam, and dextromethorphan, which are probe substrates for the enzymes CYP1A2, CYP2C9, CYP3A4/5, and CYP2D6, respectively. The botanically authenticated and chemically standardized extract of roots from G. glabra was consumed by 14 healthy menopausal and postmenopausal female participants twice daily for 2 weeks. The pharmacokinetics of each probe drug were evaluated immediately before and after supplementation with the licorice extract. Comparison of the average areas under the time-concentration curves (AUCs) for each probe substrate in serum showed no significant changes from licorice consumption, whereas time to reach peak concentration for caffeine and elimination half-life for tolbutamide showed small changes. According to the US Food and Drug Administration guidance, which is based on changes in the AUC of each probe substrate drug, the investigated licorice extract should not cause any clinically relevant pharmacokinetic interactions with respect to CYP3A4/5, CYP2C9, CYP2D6, or CYP1A2. SIGNIFICANCE STATEMENT: Despite generally-recognized-as-safe status, the licorice species Glycyrrhiza glabra has been associated with some toxicity. Preclinical studies suggest that G. glabra might cause pharmacokinetic drug interactions by inhibiting several cytochrome P450 enzymes. This phase 1 clinical study addressed these concerns by evaluating clinically relevant effects with respect to CYP3A4/5, CYP2C9, CYP2D6, and CYP1A2. These results showed that a standardized G. glabra extract did not cause any clinically relevant pharmacokinetic drug interactions with four major cytochrome P450 enzymes.

An Updated Review of the Genus Humulus: A Valuable Source of Bioactive Compounds for Health and Disease Prevention

The medicinal potential of hop (Humulus lupulus L.) is widely cited in ancient literature and is also allowed in several official pharmacopoeias for the treatment of a variety of ailments, mainly related to anxiety states. This is due to the plethora of phytoconstituents (e.g., bitter acids, polyphenols, prenyl flavonoids) present in the female inflorescences, commonly known as cones or strobili, endowed with anti-inflammatory, antioxidant, antimicrobial, and phytoestrogen activities. Hop has recently attracted the interest of the scientific community due to the presence of xanthohumol, whose strong anti-cancer activity against various types of cancer cells has been well documented, and for the presence of 8-prenyl naringenin, the most potent known phytoestrogen. Studies in the literature have also shown that hop compounds can hinder numerous signalling pathways, including ERK1/2 phosphorylation, regulation of AP-1 activity, PI3K-Akt, and nuclear factor NF-κB, which are the main targets of the antiproliferative action of bitter acids and prenylflavonoids. In light of these considerations, the aim of this review was to provide an up-to-date overview of the main biologically active compounds found in hops, as well as their in vitro and in vivo applications for human health and disease prevention. To this end, a quantitative literature analysis approach was used, using VOSviewer software to extract and process Scopus bibliometric data. In addition, data on the pharmacokinetics of bioactive hop compounds and clinical studies in the literature were analysed. To make the information more complete, studies on the beneficial properties of the other two species belonging to the genus Humulus, H. japonicus and H. yunnanensis, were also reviewed for the first time.

HDI Highlighter, The First Intelligent Tool to Screen the Literature on Herb-Drug Interactions

Herbal food supplements are commonly used and can be an important part of patient self-care. Like all other bio-active and therapeutic products, they have a benefit/risk balance. These products are not without adverse effects and potentially interact with other therapies. Educating patients and providing information for health professionals about the risk of herb-drug interactions is key. One of the purposes of the biomedical literature is to inform prescribers. Scientific literature accessible on databases such as PubMed is dense and careful reading is time consuming. We propose a reading aid tool named "HDI highlighter" to help readers to find key information in clinical studies and case reports describing herb-drug interactions. It uses natural language processing algorithms (artificial intelligence) with a pharmaceutical focus. Semantic relation extraction for herb-drug interactions from the biomedical literature are overexpressed using keywords. We have tested it to review 120 published articles over the last 10 years. In these articles, we have shown that case reports often involved long-term or semi-long-term treatments such as cancer or human immunodeficiency virus therapies, antiepileptic drugs, or central nervous system drugs. Similarly, these classes of drugs are more extensively targeted by clinical studies. Herb-drug interactions described in case reports are identified in medicinal, recreational, and alimentary uses. They also usually lack a rigorous description of the herb(s) involved. Typically, clinical studies provide a complete description of protocols and dosages, with a few exceptions explained by patients' needs. Clinical studies on herbs are nevertheless conducted on a limited number of patients. All these limitations make the interpretation of herb-drug interactions complicated, but the HDI highlighter provides a quick overview of the herb-drug interaction literature.

Synthesis of Human Phase I and Phase II Metabolites of Hop (Humulus lupulus) Prenylated Flavonoids

Hop prenylated flavonoids have been investigated for their in vivo activities due to their broad spectrum of positive health effects. Previous studies on the metabolism of xanthohumol using untargeted methods have found that it is first degraded into 8-prenylnaringenin and 6-prenylnaringenin, by spontaneous cyclisation into isoxanthohumol, and subsequently demethylated by gut bacteria. Further combinations of metabolism by hydroxylation, sulfation, and glucuronidation result in an unknown number of isomers. Most investigations involving the analysis of prenylated flavonoids used surrogate or untargeted approaches in metabolite identification, which is prone to errors in absolute identification. Here, we present a synthetic approach to obtaining reference standards for the identification of human xanthohumol metabolites. The synthesised metabolites were subsequently analysed by qTOF LC-MS/MS, and some were matched to a human blood sample obtained after the consumption of 43 mg of micellarised xanthohumol. Additionally, isomers of the reference standards were identified due to their having the same mass fragmentation pattern and different retention times. Overall, the methods unequivocally identified the metabolites of xanthohumol that are present in the blood circulatory system. Lastly, in vitro bioactive testing should be applied using metabolites and not original compounds, as free compounds are scarcely found in human blood.

Herb-Drug Interactions: Worlds Intersect with the Patient at the Center

This review examines three bodies of literature related to herb-drug interactions: case reports, clinical studies, evaluations found in six drug interaction checking resources. The aim of the study is to examine the congruity of resources and to assess the degree to which case reports signal for further study. A qualitative review of case reports seeks to determine needs and perspectives of case report authors. Methods: Systematic search of Medline identified clinical studies and case reports of interacting herb-drug combinations. Interacting herb-drug pairs were searched in six drug interaction resources. Case reports were analyzed qualitatively for completeness and to identify underlying themes. Results: Ninety-nine case-report documents detailed 107 cases. Sixty-five clinical studies evaluated 93 mechanisms of interaction relevant to herbs reported in case studies, involving 30 different herbal products; 52.7% of these investigations offered evidence supporting reported reactions. Cohen's kappa found no agreement between any interaction checker and case report corpus. Case reports often lacked full information. Need for further information, attitudes about herbs and herb use, and strategies to reduce risk from interaction were three primary themes in the case report corpus. Conclusions: Reliable herb-drug information is needed, including open and respectful discussion with patients.

No Clinically Relevant Pharmacokinetic Interactions of a Red Clover Dietary Supplement with Cytochrome P450 Enzymes in Women

Extracts of red clover (Trifolium pratense L.), containing estrogenic isoflavones like genistein and daidzein and the proestrogenic isoflavones formononetin and biochanin A, are used by women as dietary supplements for the management of menopausal symptoms. Although marketed as a safer alternative to hormone therapy, red clover isoflavones have been reported to inhibit some cytochrome P450 (CYP) enzymes involved in drug metabolism. To evaluate the potential for clinically relevant drug-red clover interactions, we tested a standardized red clover dietary supplement (120 mg isoflavones per day) for interactions with the pharmacokinetics of four FDA-approved drugs (caffeine, tolbutamide, dextromethorphan, and alprazolam) as probe substrates for the enzymes CYP1A2, CYP2C9, CYP2D6, and CYP3A4/5, respectively. Fifteen peri- and postmenopausal women completed pharmacokinetic studies at baseline and 2 weeks after consuming red clover. The averaged pharmacokinetic profiles of probe substrates in serum showed no significant alterations and no changes in the areas under the curve (AUC) over 96 h. Subgroup analysis based on the demographic characteristics (BMI, menopausal status, race, and age) also showed no differences in AUC for each probe substrate. Analysis of red clover isoflavones in serum showed primarily conjugated metabolites that explain, at least in part, the red clover pharmacokinetic safety profile.