Opportunities and Challenges of Kava in Lung Cancer Prevention.

Lung cancer is the leading cause of cancer-related deaths due to its high incidence, late diagnosis, and limited success in clinical treatment. Prevention therefore is critical to help improve lung cancer management. Although tobacco control and tobacco cessation are effective strategies for lung cancer prevention, the numbers of current and former smokers in the USA and globally are not expected to decrease significantly in the near future. Chemoprevention and interception are needed to help high-risk individuals reduce their lung cancer risk or delay lung cancer development. This article will review the epidemiological data, pre-clinical animal data, and limited clinical data that support the potential of kava in reducing human lung cancer risk via its holistic polypharmacological effects. To facilitate its future clinical translation, advanced knowledge is needed with respect to its mechanisms of action and the development of mechanism-based non-invasive biomarkers in addition to safety and efficacy in more clinically relevant animal models.

Dietary Phytochemicals as Potential Chemopreventive Agents against Tobacco-Induced Lung Carcinogenesis.

Lung cancer is the second most common cancer in the world. Cigarette smoking is strongly connected with lung cancer. Benzo[a]pyrene (BaP) and 4-(N-methyl-N-nitrosamine)-1-(3-pyridyl)-butanone (NNK) are the main carcinogens in cigarette smoking. Evidence has supported the correlation between these two carcinogens and lung cancer. Epidemiology analysis suggests that lung cancer can be effectively prevented through daily diet adjustments. This review aims to summarize the studies published in the past 20 years exploring dietary phytochemicals using Google Scholar, PubMed, and Web of Science databases. Dietary phytochemicals mainly include medicinal plants, beverages, fruits, vegetables, spices, etc. Moreover, the perspectives on the challenges and future directions of dietary phytochemicals for lung cancer chemoprevention will be provided. Taken together, treatment based on the consumption of dietary phytochemicals for lung cancer chemoprevention will produce more positive outcomes in the future and offer the possibility of reducing cancer risk in society.

Reducing tobacco-associated lung cancer risk: a study protocol for a randomized clinical trial of AB-free kava.

BACKGROUND: Tobacco use is the leading cause of many preventable diseases, resulting in premature death or disease. Given that the majority of adult who smoke want to stop, this health burden could be significantly reduced if the success rate of tobacco cessation can be improved. In addition, most adults planning to quit were interested in trying complementary approaches to facilitating tobacco cessation, which is currently lacking. Therefore, there is an unmet and urgent need for novel interventions to improve the success of tobacco cessation. If such an intervention can reduce tobacco-associated lung carcinogenesis, that will be more desirable. The goal of this project is to develop a safe and effective kava-based intervention to enable tobacco cessation and reduce lung cancer risk, which will improve the health of smokers. METHODS: A randomized controlled trial will enroll 80 adults who currently smoke at least 10 cigarettes daily and randomize 1:1 into the placebo and AB-free kava arms, being exposed for 4 weeks, with a total of six visits (weeks 0, 1, 2, 4, 8, and 12) to evaluate the compliance and potential issues of AB-free kava use among the participants, explore the potential effect of the AB-free kava intervention on tobacco dependence, tobacco use, and lung carcinogenesis biomarkers. Participants will be enrolled during their primary care clinic visit. DISCUSSION: Primary care settings play a critical role in tobacco-related disease screening, counseling, and early intervention, as the majority of adults who smoke visit their physicians annually. Building upon our promising pilot human trial results in conjunction with ample compelling lab animal results, and consistent with evidence of kava's benefits from epidemiological data, this trial will evaluate the compliance of AB-free kava among adults who currently smoke with no intention to quit. The other exploratory aims include (1) whether AB-free kava intervention can reduce tobacco use and tobacco dependence; (2) whether AB-free kava use suppresses tobacco-induced carcinogenesis; and (3) the potential of the mechanism-based noninvasive biomarkers in precision AB-free kava intervention. The positive results from this study are expected to provide a great opportunity to effectively reduce smoking rates and tobacco-related diseases. TRIAL REGISTRATION: ClinicalTrials.gov with the identifier: NCT05081882. Registered on October 18, 2021.

Clinical pharmacokinetics of kavalactones after oral dosing of standardized kava extract in healthy volunteers.

ETHNOPHARMACOLOGICAL RELEVANCE: Piper methysticum G. Forst. (Piperaceae), commonly known as kava, has been used as a traditional beverage for centuries for its relaxing properties. Kavalactones are considered to be the major constituents responsible for kava's beneficial effects. Despite the extensive use of kava, clinical pharmacokinetic data is not available in the literature; therefore, the findings of this study will be critical for the dosage calculations for future clinical evaluation of kava. AIM OF THE STUDY: The aim of the current study is to examine the clinical pharmacokinetics of six major kavalactones following oral dosing of flavokavain A/B-free standardized kava extract capsules in healthy volunteers using two dosage regimens. MATERIALS AND METHODS: A sensitive, reliable, and specific ultra-high pressure liquid chromatography-mass spectrometry (UPLC-MS/MS) method was developed and validated for the simultaneous quantification of six major kavalactones (kavain, dihydrokavain, methysticin, dihydromethysticin, yangonin, and desmethoxyyangonin) and two flavokavains (A and B) in human plasma. Pharmacokinetic profiles were assessed in ten healthy volunteers after oral doses of standardized kava product, and plasma samples were analyzed for six kavalactones and two flavokavains using the validated UPLC-MS/MS method. Concentration-time data was subjected to pharmacokinetic analysis. RESULTS: The systemic exposure of the kavalactones was found to be in the following order: dihydrokavain > dihydromethysticin > kavain > methysticin > yangonin. Desmethoxyyangonin was quantifiable only at a couple of time points, while flavokavain A and flavokavain B were not present in any of the plasma samples. Fast absorption of five kavalactones was observed with time to reach the maximum plasma concentration of 1-3 h. A dose proportionality in pharmacokinetics was established from 75 to 225 mg of kavalactone doses. In the multiple-dose study, a significant reduction in the extent of absorption of kavalactones with food was observed. CONCLUSION: Single and multiple-dose clinical pharmacokinetic studies for kava were performed in healthy volunteers, and higher exposure to the kavalactones was observed after single-dosing (225 mg), while a longer duration of exposure was observed after three times a day (3 x 75 mg) dosing.

Angelica gigas: Signature Compounds, In Vivo Anticancer, Analgesic, Neuroprotective and Other Activities, and the Clinical Translation Challenges.

Angelica gigas Nakai (AGN) root is a medicinal herbal widely used in traditional medicine in Korea. AGN root ethanolic extract dietary supplements are marketed in the United States for memory health and pain management. We comprehensively reviewed the anticancer, analgesic, pro-memory and other bio-activities of AGN extract and its signature phytochemicals decursin, decursinol angelate, and decursinol a decade ago in 2012 and updated their anticancer activities in 2015. In the last decade, significant progress has been made for understanding the pharmacokinetics (PK) and metabolism of these compounds in animal models and single dose human PK studies have been published by us and others. In addition to increased knowledge of the known bioactivities, new bioactivities with potential novel health benefits have been reported in animal models of cerebral ischemia/stroke, anxiety, sleep disorder, epilepsy, inflammatory bowel disease, sepsis, metabolic disorders, osteoporosis, osteoarthritis, and even male infertility. Herein, we will update PK and metabolism of pyranocoumarins, review in vivo bioactivities from animal models and human studies, and critically appraise the relevant active compounds, the cellular and molecular pharmacodynamic targets, and pertinent mechanisms of action. Knowledge gaps include whether human pyranocoumarin PK metrics are AGN dose dependent and subjected to metabolic ceiling, or metabolic adaptation after repeated use. Critical clinical translation challenges include sourcing of AGN extracts, product consistency and quality control, and AGN dose optimization for different health conditions and disease indications. Future research directions are articulated to fill knowledge gaps and address these challenges.

In vitro inhibition of carboxylesterase 1 by Kava (Piper methysticum) Kavalactones.

Kava refers to the extracts from the rhizome of the plant Piper methysticum which is of particular significance to various indigenous cultures in the South Pacific region. Kavalactones are the active constituents of kava products and are associated with sedative and anxiolytic effects. Kavalactones have been evaluated in vitro for their potential to alter the activity of various CYP450 enzymes but have undergone little systematic investigation as to their potential influence on esterases. This study investigated the inhibition effects of kava and its kavalactones on carboxylesterase 1 (CES1) in an in vitro system and established associated kinetic parameters. Kava and its kavalactones were found to produce reversible inhibition of CES1 to varying degrees. Kavain, dihydrokavain, and desmethoxyyangonin displayed competitive type inhibition, while methysticin, dihydromethysticin, and yangonin displayed a mixed competitive-noncompetitive type inhibition. The inhibition constants (Ki) values for each of the kavalactones were as follows: methysticin (35.2 µM), dihydromethysticin (68.2 µM), kavain (81.6 µM), dihydrokavain (105.3 µM), yangonin (24.9 µM), and desmethoxyyangonin (25.2 µM). With consideration to the in vitro Ki for each evaluated kavalactone as well as available clinical kavalactone concentrations in blood circulation, co-administration of CES1 substrate medications and kava products at the recommended daily dose is generally free of drug interaction concerns. However, uncertainty around kavalactone exposure in humans has been noted and a clinically relevant CES1 inhibition by kavain, dihydrokavain, and dihydromethysticin is indeed possible if the kavalactone consumption is higher than 1000 mg in the context of over-the-counter usage. Further clinical studies would be required to assess the possibility of clinically significant kava drug-drug interactions with CES1 substrate medications.

Characterization of Different Forms of Kava (Piper methysticum) Products by UPLC-MS/MS.

There are several forms of kava (Piper methysticum) products available for human consumption, and many factors are known to influence their chemical compositions and therefore their pharmacological properties. Because of the increased popularity of kava intake, a rigorous characterization of their content diversity is prerequisite, particularly due to its known potential to cause hepatotoxicity. To understand the composition diversity of kavalactones and flavokavains in commercial kava products, we developed a UPLC-MS/MS-based analytical method for the quantification of six kavalactones (kavain, dihydrokavain, methysticin, dihydromethysticin, yangonin and desmethoxyyangonin) and two flavokavains (flavokavains A and B) and analyzed their contents in 28 different kava products in the form of capsules, tinctures, traditional aqueous suspensions and dried powders. Our results demonstrated a great variation in terms of the total and relative abundance of the analyzed kavalactones and flavokavains among the analyzed kava preparations. More importantly, the kavalactone abundance in the product label could differ up to 90% from our experimental measurements. Therefore, more rigorous and comprehensive quality control of kava products is required with respect to the content of individual kavalactones and flavokavains. Accurate content information is essential to understand the pharmacological properties and safety of different kava products.

Kava as a Clinical Nutrient: Promises and Challenges.

Kava beverages are typically prepared from the root of Piper methysticum. They have been consumed among Pacific Islanders for centuries. Kava extract preparations were once used as herbal drugs to treat anxiety in Europe. Kava is also marketed as a dietary supplement in the U.S. and is gaining popularity as a recreational drink in Western countries. Recent studies suggest that kava and its key phytochemicals have anti-inflammatory and anticancer effects, in addition to the well-documented neurological benefits. While its beneficial effects are widely recognized, rare hepatotoxicity had been associated with use of certain kava preparations, but there are no validations nor consistent mechanisms. Major challenges lie in the diversity of kava products and the lack of standardization, which has produced an unmet need for quality initiatives. This review aims to provide the scientific community and consumers, as well as regulatory agencies, with a broad overview on kava use and its related research. We first provide a historical background for its different uses and then discuss the current state of the research, including its chemical composition, possible mechanisms of action, and its therapeutic potential in treating inflammatory and neurological conditions, as well as cancer. We then discuss the challenges associated with kava use and research, focusing on the need for the detailed characterization of kava components and associated risks such as its reported hepatotoxicity. Lastly, given its growing popularity in clinical and recreational use, we emphasize the urgent need for quality control and quality assurance of kava products, pharmacokinetics, absorption, distribution, metabolism, excretion, and foundational pharmacology. These are essential in order to inform research into the molecular targets, cellular mechanisms, and creative use of early stage human clinical trials for designer kava modalities to inform and guide the design and execution of future randomized placebo controlled trials to maximize kava's clinical efficacy and to minimize its risks.

Oral Dosing of Dihydromethysticin Ahead of Tobacco Carcinogen NNK Effectively Prevents Lung Tumorigenesis in A/J Mice.

Our early studies demonstrated an impressive chemopreventive efficacy of dihydromethysticin (DHM), unique in kava, against tobacco carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced lung tumorigenesis in A/J mice in which DHM was supplemented in the diet. The current work was carried out to validate the efficacy, optimize the dosing schedule, and further elucidate the mechanisms using oral bolus dosing of DHM. The results demonstrated a dose-dependent chemopreventive efficacy of DHM (orally administered 1 h before each of the two NNK intraperitoneal injections, 1 week apart) against NNK-induced lung adenoma formation. Temporally, DHM at 0.8 mg per dose (∼32 mg per kg body weight) exhibited 100% lung adenoma inhibition when given 3 and 8 h before each NNK injection and attained >93% inhibition when dosed at either 1 or 16 h before each NNK injection. The simultaneous treatment (0 h) or 40 h pretreatment (-40 h) decreased lung adenoma burden by 49.8% and 52.1%, respectively. However, post-NNK administration of DHM (1-8 h after each NNK injection) was ineffective against lung tumor formation. In short-term experiments for mechanistic exploration, DHM treatment reduced the formation of NNK-induced O6-methylguanine (O6-mG, a carcinogenic DNA adduct in A/J mice) in the target lung tissue and increased the urinary excretion of NNK detoxification metabolites as judged by the ratio of urinary NNAL-O-gluc to free NNAL, generally in synchrony with the tumor prevention efficacy outcomes in the dose scheduling time-course experiment. Overall, these results suggest DHM as a potential chemopreventive agent against lung tumorigenesis in smokers, with O6-mG and NNAL detoxification as possible surrogate biomarkers.

The Impact of One-week Dietary Supplementation with Kava on Biomarkers of Tobacco Use and Nitrosamine-based Carcinogenesis Risk among Active Smokers.

Tobacco smoking is the primary risk factor for lung cancer, driven by the addictive nature of nicotine and the indisputable carcinogenicity of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) as well as other compounds. The integration of lung cancer chemoprevention with smoking cessation is one potential approach to reduce this risk and mitigate lung cancer mortality. Experimental data from our group suggest that kava, commonly consumed in the South Pacific Islands as a beverage to promote relaxation, may reduce lung cancer risk by enhancing NNK detoxification and reducing NNK-derived DNA damage. Building upon these observations, we conducted a pilot clinical trial to evaluate the effects of a 7-day course of kava on NNK metabolism in active smokers. The primary objective was to compare urinary total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL plus its glucuronides, major metabolites of NNK) before and after kava administration as an indicator of NNK detoxification. Secondary objectives included determining kava's safety, its effects on DNA damage, tobacco use, and cortisol (a biomarker of stress). Kava increased urinary excretion of total NNAL and reduced urinary 3-methyladenine in participants, suggestive of its ability to reduce the carcinogenicity of NNK. Kava also reduced urinary total nicotine equivalents, indicative of its potential to facilitate tobacco cessation. Plasma cortisol and urinary total cortisol equivalents were reduced upon kava use, which may contribute to reductions in tobacco use. These results demonstrate the potential of kava intake to reduce lung cancer risk among smokers.

Kava and its Kavalactones Inhibit Norepinephrine-induced Intracellular Calcium Influx in Lung Cancer Cells.

Kava, the extract of the roots of Piper methysticum, has been traditionally consumed in the South Pacific islands for its natural relaxing property. Epidemiological data suggests that kava consumption may reduce human cancer risk, and in vitro and in vivo models suggest chemopreventive potential against carcinogen-induced tumorigenesis. Therefore, knowledge about its molecular mechanisms and responsible ingredient(s) for these beneficial properties will better guide kava's use for the management of these disorders. Psychological stress typically results in increased production of stress hormones, such as norepinephrine (NE), which activate adrenergic receptors (ARs). Psychological stress has also been associated with increased cancer incidence and poor clinical outcomes in cancer patients. Mechanistically, binding of NE to ARs induces intracellular calcium influx, which activates downstream signaling pathways involved in both stress and cancer development. In this study, we characterized the effect of kava and its components, 3 fractions and 6 major kavalactones, on NE-induced intracellular calcium influx in H1299, a human non-small cell lung carcinoma cell line. Results show that kava extract effectively inhibits NE-mediated intracellular calcium influx in H1299 cells, potentially through antagonizing ß-AR signaling. This inhibitory activity is recapitulated by the major kavalactones in kava. Among the 6 major kavalactones, DHK demonstrated the best potency. Taken together, our study suggests a novel mechanism through which kava and its ingredients potentially offer the anxiolytic and cancer-preventive activity.

A stable isotope dilution tandem mass spectrometry method of major kavalactones and its applications.

Kava is regaining its popularity with detailed characterizations warranted. We developed an ultraperformance liquid chromatography high-resolution tandem mass spectrometry (UPLC-MS/MS) method for major kavalactones (kavain, dihydrokavain, methysticin, dihydromethysticin and desmethoxyyangonin) with excellent selectivity and specificity. The method has been validated for different matrices following the Food and Drug Administration guidance of analytical procedures and methods validation. The scope of this method has been demonstrated by quantifying these kavalactones in two kava products, characterizing their tissue distribution and pharmacokinetics in mice, and detecting their presence in human urines and plasmas upon kava intake. As expected, the abundances of these kavalactones differed significantly in kava products. All of them exhibited a large volume of distribution with extensive tissue affinity and adequate mean residence time (MRT) in mice. This method also successfully quantified these kavalactones in human body fluids upon kava consumption at the recommended human dose. This UPLC-MS/MS method therefore can be used to characterize kava products and its pharmacokinetics in animals and in humans.

Prostate Cancer Xenograft Inhibitory Activity and Pharmacokinetics of Decursinol, a Metabolite of Angelica gigas Pyranocoumarins, in Mouse Models.

We have previously shown that the ethanol extract of dried Angelica gigas Nakai (AGN) root exerts anticancer activity against androgen receptor (AR)-negative human DU145 and PC-3 prostate cancer xenografts and primary carcinogenesis in the transgenic adenocarcinoma of mouse prostate (TRAMP) model. The major pyranocoumarin isomers decursin (D) and decursinol angelate (DA), when provided at equi-molar intake to that provided by AGN extract, accounted for the inhibitory efficacy against precancerous epithelial lesions in TRAMP mice. Since we and others have shown in rodents and humans that D and DA rapidly and extensively convert to decursinol, here we tested whether decursinol might be an in vivo active compound for suppressing xenograft growth of human prostate cancer cells expressing AR. In SCID-NSG mice carrying subcutaneously inoculated human LNCaP/AR-Luc cells overexpressing the wild type AR, we compared the efficacy of 4.5[Formula: see text]mg decursinol per mouse with equi-molar dose of 6[Formula: see text]mg D/DA per mouse. The result showed that decursinol decreased xenograft tumor growth by 75% and the lung metastasis, whereas D/DA exerted a much less effect. Measurement of plasma decursinol concentration, at 3[Formula: see text]h after the last dose of respective dosing regimen, showed higher circulating level in the decursinol-treated NSG mice than in the D/DA-treated mice. In a subsequent single-dose pharmacokinetic experiment, decursinol dosing led to 3.7-fold area under curve (AUC) of plasma decursinol over that achieved by equi-molar D/DA dosing. PK advantage notwithstanding, decursinol represents an active compound to exert in vivo prostate cancer growth and metastasis inhibitory activity in the preclinical model.

Pyranocoumarin Tissue Distribution, Plasma Metabolome and Prostate Transcriptome Impacts of Sub-Chronic Exposure to Korean Angelica Supplement in Mice.

Herbal products containing Korean Angelica gigas Nakai (AGN) root extract are marketed as dietary supplements for memory enhancement, pain killing, and female menopausal symptom relief. We have shown the anticancer activities of AGN supplements in mouse models. To facilitate human anticancer translational research, we characterized the tissue distribution of AGN marker pyranocoumarin compounds decursin (D) and decursinol angelate (DA) ([Formula: see text]% in AGN) and their metabolite decursinol (DOH), assessed the safety of sub-chronic AGN dietary exposure in mice, and explored its impact on plasma aqueous metabolites and the prostate transcriptome. The data show that after a gavage dose, plasma contained readily detectable DOH, but little D and DA, mirroring patterns in the liver. Extra-hepatic tissues retained greater levels of DA and D than the liver did. For sub-chronic exposures, male mice were provided ad libitum AIN93M-pellet diets with 0.5 and 1% AGN for six weeks. No adverse effects were observed on the plasma biochemistry markers of liver and kidney integrity in spite of their enlargement. Histopathological examinations of the liver, kidney and other visceral organs did not reveal tissue abnormalities. Metabolomic assessment of plasma from mice fed the 1%-AGN diet suggested metabolic shifts of key amino acids especially in the methionine-cysteine cycle, purine cycle, and glycolysis-citrate cycle. Prostate transcriptomic profiling identified gene signature changes in the metabolisms of drugs, lipids and cellular energetics, neuro-muscular features, immunity and inflammation, and tumor suppressor/oncogene balance. The safety profile was corroborated with a daily [Formula: see text] injection of AGN extract (100-300[Formula: see text]mg/kg) for four weeks, which resulted in much greater systemic pyranocoumarin exposure than the dietary route did.

Gene expression signatures associated with suppression of TRAMP prostate carcinogenesis by a kavalactone-rich Kava fraction.

Kava (Piper methysticum Forster) extract and its major kavalactones have been shown to block chemically induced lung tumor initiation in mouse models. Here we evaluated the chemopreventive effect of a kavalactone-rich Kava fraction B (KFB), free of flavokavains, on carcinogenesis in a transgenic adenocarcinoma of mouse prostate (TRAMP) model and characterized the prostate gene expression signatures. Male C57BL/6 TRAMP mice were fed AIN93M diet with or without 0.4% KFB from 8 wk of age. Mice were euthanized at 16 or 28 wk. The growth of the dorsolateral prostate (DLP) lobes in KFB-treated TRAMP mice was inhibited by 66% and 58% at the respective endpoint. Anterior and ventral prostate lobes in KFB-treated TRAMP mice were suppressed by 40% and 49% at 28 wk, respectively. KFB consumption decreased cell proliferation biomarker Ki-67 and epithelial lesion severity in TRAMP DLP, without detectable apoptosis enhancement. Real time qRT-PCR detection of mRNA from DLP at 28 wk showed decreased expression of cell cycle regulatory genes congruent with Ki-67 suppression. Microarray profiling of DLP mRNA indicated that "oncogene-like" genes related to angiogenesis and cell proliferation were suppressed by KFB but tumor suppressor, immunity, muscle/neuro, and metabolism-related genes were upregulated by KFB in both TRAMP and WT DLP. TRAMP mice fed KFB diet developed lower incidence of neuroendocrine carcinomas (NECa) (2 out of 14 mice) than those fed the basal diet (8 out of 14 mice, χ2 = 5.6, P < 0.025). KFB may, therefore, inhibit not only TRAMP DLP epithelial lesions involving multiple molecular pathways, but also NECa. © 2016 Wiley Periodicals, Inc.

Cancer Chemoprevention with Korean Angelica: Active Compounds, Pharmacokinetics, and Human Translational Considerations.

Angelica gigas Nakai (AGN) is a major medicinal herb used in Korea and several other Asian countries. Traditionally, its dried root has been used to treat anemia, pain, infection and articular rheumatism, most often through boiling in water to prepare the dosage forms. AGN extract or AGN-containing herbal mixtures are sold in the US and globally as dietary supplements for pain killing, memory enhancement and post-menopausal symptom relief. Decursin (D) and its isomer decursinol angelate (DA) are the major chemicals in the alcoholic extracts of the root of AGN. The anti-cancer activity of AGN alcoholic extract has been established in a number of animal cancer models, including a transgenic model of prostate carcinogenesis. Cell culture structure-activity studies have uncovered distinct cellular and molecular effects of D and DA vs. their pyranocoumarin core decursinol (DOH) with respect to cancer cells and those associated with their microenvironment. Pharmacokinetic (PK) study by us and others in rodent models indicated that DOH is the major and rapid in vivo first-pass liver metabolite of D and DA. Cognizant of metabolic differences among rodents and humans, we carried out a first-in-human PK study of D/DA to inform the translational relevance of efficacy and mechanism studies with rodent models. The combined use of vigorous animal tests and human PK studies can provide stronger scientific rationale to inform design and execution of translational studies to move AGN toward evidence-based herbal medicine.

Kava for the treatment of generalised anxiety disorder (K-GAD): study protocol for a randomised controlled trial.

BACKGROUND: Generalised anxiety disorder (GAD) is a chronic and pervasive condition that generates high levels of psychological stress, and it is difficult to treat in the long term. Current pharmacotherapeutic options for GAD are in some cases only modestly effective, and may elicit undesirable side effects. Through targeted actions on the gamma-aminobutyric acid (GABA) pathway, the South Pacific medicinal plant kava (Piper methysticum) is a non-addictive, non-hypnotic anxiolytic with the potential to treat GAD. The evidence for the efficacy of kava for treating anxiety has been affirmed through clinical trials and meta-analyses. Recent research has also served to lessen safety concerns regarding the use of kava due to hepatotoxic risk, which is reflected in a recent German court overturning the previous kava ban in that country (which may in turn influence a reinstatement by the European Union). The aim of current research is to assess the efficacy of an 'aqueous noble cultivar rootstock extract' of kava in GAD in a larger longer term study. In addition, we plan to investigate the pharmacogenomic influence of GABA transporters on response, effects of kava on gene expression, and for the first time, the neurobiological correlates of treatment response via functional and metabolic imaging. METHODS/DESIGN: This clinical trial is funded by the Australian National Health and Medical Research Council (APP1063383) and co-funded by MediHerb (Integria Healthcare (Australia) Pty. Ltd). The study is a phase III, multi-site, two-arm, 18-week, randomised, double-blind, placebo-controlled study using an aqueous extract of noble kava cultivar (standardised to 240 mg of kavalactones per day) versus matching placebo in 210 currently anxious participants with diagnosed GAD who are non-medicated. The study takes place at two sites: the Centre for Human Psychopharmacology (Swinburne University of Technology), Hawthorn, Melbourne, Australia; and the Academic Discipline of Psychiatry (The University of Queensland) based at the Royal Brisbane and Women's Hospital, Herston, Brisbane, Australia. Written informed consent will be obtained from each participant prior to commencement in the study. The primary outcome is the Structured Interview Guide for the Hamilton Anxiety Rating Scale (SIGH-A). The secondary outcomes involve a range of scales that assess affective disorder symptoms and quality of life outcomes, in addition to the study of mediating biomarkers of response (assessed via genomics and neuroimaging). DISCUSSION: If this study demonstrates positive findings in support of the superiority of kava over placebo in the treatment of GAD, and also is shown to be safe, then this plant-medicine can be considered a 'first-line' therapy for GAD. Genomic and neuroimaging data may reveal clinical response patterns and provide more evidence of the neurobiological activity of the plant extract. TRIAL REGISTRATION INFORMATION: ClinicalTrials.gov: NCT02219880 Date: 13 August 2014:.

Cytochrome P450 Isoforms in the Metabolism of Decursin and Decursinol Angelate from Korean Angelica.

We have shown that the in vitro hepatic microsomal metabolism of pyranocoumarin compound decursinol angelate (DA) to decursinol (DOH) exclusively requires cytochrome P450 (CYP) enzymes, whereas the conversion of its isomer decursin (D) to DOH can be mediated by CYP and esterase(s). To provide insight into specific isoforms involved, here we show with recombinant human CYP that 2C19 was the most active at metabolizing D and DA in vitro followed by 3A4. With carboxylesterases (CES), D was hydrolyzed by CES2 but not CES1, and DA was resistant to both CES1 and CES2. In human liver microsomal (HLM) preparation, the general CYP inhibitor 1-aminobenzotriazole (ABT) and respective competitive inhibitors for 2C19 and 3A4, (+)-N-3-benzylnirvanol (NBN) and ketoconazole substantially retarded the metabolism of DA and, to a lesser extent, of D. In healthy human subjects from a single-dose pharmacokinetic (PK) study, 2C19 extensive metabolizer genotype (2C19*17 allele) tended to have less plasma DA AUC0-48h and poor metabolizer genotype (2C19*2 allele) tended to have greater DA AUC0-48h. In mice given a single dose of D/DA, pretreatment with ABT boosted the plasma and prostate levels of D and DA by more than an order of magnitude. Taken together, our findings suggest that CYP isoforms 2C19 and 3A4 may play a crucial role in the first pass liver metabolism of DA and, to a lesser extent, that of D in humans. Pharmacogenetics with respect to CYP genotypes and interactions among CYP inhibitor drugs and D/DA should therefore be considered in designing future translation studies of DA and/or D.

Chemopreventive Effects of Korean Angelica versus Its Major Pyranocoumarins on Two Lineages of Transgenic Adenocarcinoma of Mouse Prostate Carcinogenesis.

We showed previously that daily gavage of Angelica gigas Nakai (AGN) root ethanolic extract starting 8 weeks of age inhibited growth of prostate epithelium and neuroendocrine carcinomas (NE-Ca) in the transgenic adenocarcinoma of mouse prostate (TRAMP) model. Because decursin (D) and its isomer decursinol angelate (DA) are major pyranocoumarins in AGN extract, we tested the hypothesis that D/DA represented active/prodrug compounds against TRAMP carcinogenesis. Three groups of male C57BL/6 TRAMP mice were gavage treated daily with excipient vehicle, AGN (5 mg per mouse), or equimolar D/DA (3 mg per mouse) from 8 weeks to 16 or 28 weeks of age. Measurement of plasma and NE-Ca D, DA, and their common metabolite decursinol indicated similar retention from AGN versus D/DA dosing. The growth of TRAMP dorsolateral prostate (DLP) in AGN- and D/DA-treated mice was inhibited by 66% and 61% at 16 weeks and by 67% and 72% at 28 weeks, respectively. Survival of mice bearing NE-Ca to 28 weeks was improved by AGN, but not by D/DA. Nevertheless, AGN- and D/DA-treated mice had lower NE-Ca burden. Immunohistochemical and mRNA analyses of DLP showed that AGN and D/DA exerted similar inhibition of TRAMP epithelial lesion progression and key cell-cycle genes. Profiling of NE-Ca mRNA showed a greater scope of modulating angiogenesis, epithelial-mesenchymal transition, invasion-metastasis, and inflammation genes by AGN than D/DA. The data therefore support D/DA as probable active/prodrug compounds against TRAMP epithelial lesions, and they cooperate with non-pyranocoumarin compounds to fully express AGN efficacy against NE-Ca.