Kava kava: examining new reports of toxicity

AB-free kava enhances resilience against the adverse health effects of tobacco smoke in mice

Tobacco smoke remains a serious global issue, resulting in serious health complications, contributing to the onsets of numerous preventive diseases, and imposing significant financial burdens. Despite regulatory policies and cessation measures aimed at curbing its usage, novel interventions are urgently needed for effective damage reduction. Our preclinical and pilot clinical studies showed that AB-free kava has the potential to reduce tobacco smoke-induced lung cancer risk, mitigate tobacco dependence, and reduce tobacco use. To understand the scope of its benefits in damage reduction and potential limitations, this study evaluated the effects of AB-free kava on a panel of health indicators in mice exposed to 2 - 4 weeks of daily tobacco smoke exposure. Our comprehensive assessments included global transcriptional profiling of the lung and liver tissues, analysis of lung inflammation, evaluation of lung function, exploration of tobacco nicotine withdrawal, and characterization of the causal PKA signaling pathway. As expected, Tobacco smoke exposure perturbed a wide range of biological processes and compromised multiple functions in mice. Remarkably, AB-free kava demonstrated the ability to globally mitigate tobacco smoke-induced deficits at the molecular and functional levels with promising safety profiles, offering a unique promise to mitigate tobacco smoke-related health damages. Further pre-clinical evaluation and clinical translation are warranted to fully harness the potential of AB-free kava in combating tobacco smoke-related harms.

Antiviral effects of micafungin against pteropine orthoreovirus, an emerging zoonotic virus carried by bats

Bat-borne emerging zoonotic viruses cause major outbreaks, such as the Ebola virus, Nipah virus, and/or beta coronavirus. Pteropine orthoreovirus (PRV), whose spillover event occurred from fruits bats to humans, causes respiratory syndrome in humans widely in South East Asia. Repurposing approved drugs against PRV is an effective tool to confront future PRV pandemics. We screened 2,943 compounds in an FDA-approved drug library and identified eight hit compounds that reduce viral cytopathic effects on cultured Vero cells. Real-time quantitative PCR analysis revealed that six of eight hit compounds significantly inhibited PRV replication. Among them, micafungin used clinically as an antifungal drug, displayed a prominent antiviral effect on PRV. Secondly, the antiviral effects of micafungin on PRV infected human cell lines (HEK293T and A549), and their transcriptome changes by PRV infection were investigated, compared to four different bat-derived cell lines (FBKT1 (Ryukyu flying fox), DEMKT1 (Leschenault's rousette), BKT1 (Greater horseshoe bat), YUBFKT1 (Eastern bent-wing bats)). In two human cell lines, unlike bat cells that induce an IFN-γ response pathway, an endoplasmic reticulum stress response pathway was commonly activated. Additionally, micafungin inhibits viral release rather than suppressing PRV genome replication in human cells, although it was disturbed in Vero cells. The target of micafungin's action may vary depending on the animal species, but it must be useful for human purposes as a first choice of medical care.

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.

Kava (Piper methysticum) in the United States: the quiet rise of a substance with often subtle effects

Background: Piper methysticum, commonly called kava, has long been consumed in beverage form in the Pacific Islands. Kava use in the US has slowly increased since the 1990s, but is not assessed in major epidemiological surveys.Objectives: To analyze social-media posts about kava from current, past, and prospective users, for motivations, patterns of co-use, and effects.Methods: Text from Reddit posts, and accompanying metadata, were collected and thematically coded by two independent raters.Results: 423 posts were collected, spanning January 2006 through December 2021. Of the 1,211 thematic codes applied, 1,098 (90. 7%) were concordant. Motivations for use bifurcated into self-treatment (for psychiatric or physical health conditions) and recreation; these were not mutually exclusive. Kava was rarely considered strongly euphoriant, but was valued as an anxiolytic. Kava was frequently used with other substances, most commonly kratom. Kava was used at lower doses for self-treatment than for other purposes (pseudo-R² = 0.11). Undesirable effects (gastrointestinal upset, fatigue) were mentioned, though less often than benefits. Hepatotoxicity, reported elsewhere as a rare, non-dose-related risk, was disputed on the basis of its not having been experienced by those posting.Conclusion: Kava appears to be conceptualized among Reddit posters as an anxiolytic with few risks or adverse effects. As it grows in popularity, especially among people who use other drugs that are more liable to misuse or addiction, it should be assessed in probability samples (i.e. in the major national drug surveys) and clinical practice for its risks, potential benefits, and possible drug-drug interactions.

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.

An Updated Review on the Psychoactive, Toxic and Anticancer Properties of Kava

Kava (Piper methysticum) has been widely consumed for many years in the South Pacific Islands and displays psychoactive properties, especially soothing and calming effects. This plant has been used in Western countries as a natural anxiolytic in recent decades. Kava has also been used to treat symptoms associated with depression, menopause, insomnia, and convulsions, among others. Along with its putative beneficial health effects, kava has been associated with liver injury and other toxic effects, including skin toxicity in heavy consumers, possibly related to its metabolic profile or interference in the metabolism of other xenobiotics. Kava extracts and kavalactones generally displayed negative results in genetic toxicology assays although there is sufficient evidence for carcinogenicity in experimental animals, most likely through a non-genotoxic mode of action. Nevertheless, the chemotherapeutic/chemopreventive potential of kava against cancer has also been suggested. Both in vitro and in vivo studies have evaluated the effects of flavokavains, kavalactones and/or kava extracts in different cancer models, showing the induction of apoptosis, cell cycle arrest and other antiproliferative effects in several types of cancer, including breast, prostate, bladder, and lung. Overall, in this scoping review, several aspects of kava efficacy and safety are discussed and some pertinent issues related to kava consumption are identified.

In vivo Structure-Activity Relationship of Dihydromethysticin in Reducing Nicotine-Derived Nitrosamine Ketone (NNK)-Induced Lung DNA Damage against Lung Carcinogenesis in A/J Mice

Lung cancer is the leading cause of cancer-related deaths and chemoprevention should be developed. We recently identified dihydromethysticin (DHM) as a promising candidate to prevent NNK-induced lung tumorigenesis. To probe its mechanisms and facilitate its future translation, we investigated the structure-activity relationship of DHM on NNK-induced DNA damage in A/J mice. Twenty DHM analogs were designed and synthesized. Their activity in reducing NNK-induced DNA damage in the target lung tissues was evaluated. The unnatural enantiomer of DHM was identified to be more potent than the natural enantiomer. The methylenedioxy functional moiety did not tolerate modifications while the other functional groups (the lactone ring and the ethyl linker) accommodated various modifications. Importantly, analogs of high structural similarity to DHM with distinct efficacy in reducing NNK-induced DNA damage have been identified. They will serve as chemical probes to elucidate the mechanisms of DHM in blocking NNK-induced lung carcinogenesis.

Prevalence of drug-drug interactions in sarcoma patients: key role of the pharmacist integration for toxicity risk management

BACKGROUND

The risk of drug-drug interactions (DDI) has become a major issue in cancer patients. However, data in sarcoma patients are scarce. We aimed to evaluate the frequency and the factors associated with DDI with antitumor treatments, and to evaluate the impact of a pharmacist evaluation before anticancer treatment.

PATIENTS AND METHODS

We performed a retrospective review of consecutive sarcoma patients starting chemotherapy (CT) or Tyrosine kinase inhibitor (TKI). A pharmacist performed medication reconciliation and established an early toxicity risk assessment. Potential DDI with antitumor drugs were identified using Micromedex electronic software.

RESULTS

One hundred and twenty-two soft-tissue and 80 bone sarcoma patients (103 males, median age 50 years,) were included before CT (86%) or TKI (14%). The median number of medications was 3; 34 patients (22% of patients with medication reconciliation) reported complementary medicine use. 37 potential DDI classified as major, were identified (12% of the 243 pre-therapeutic assessments). In multivariate analysis, TKI (p < 0.0001), proton pump inhibitor (p = 0.026) and antidepressant (p < 0.001) were identified as risk factors of DDI (p < 0.02). Only marital status (p = 0.003) was associated with complementary medicine use. A pharmacist performed 157 medication reconciliations and made 71 interventions among 59 patients (37%). In multivariate analysis, factors associated with pharmacist intervention were: complementary medicines (p = 0.004), drugs number (p = 0.005) and treatment with TKI (p = 0.0002) CONCLUSIONS: Clinical interventions on DDI are more frequently required among sarcoma patients treated with TKI than CT. Multidisciplinary risk assessment including a medication reconciliation by a pharmacist could be crucial to prevent DDI with TKI.

Prevalence of potential interactions of medications, including herbs and supplements, before, during, and after chemotherapy in patients with breast and prostate cancer

BACKGROUND

The use of herbs and supplements (HS) is common among patients with cancer, yet limited information exists about potential medication interactions (PMIs) with HS use around chemotherapy.

METHODS

Patients with breast or prostate cancer who had recently finished chemotherapy at 2 academic medical centers were surveyed by telephone. Interviewers inquired about all medications, including HS, before, during, and after chemotherapy. Micromedex, Lexicomp, and Natural Medicines Comprehensive Database interaction software programs were used to determine PMIs.

RESULTS

A total of 67 subjects (age range, 39-77 years) were evaluated in this study. Participants were primarily White patients (73%) with breast cancer (87%). The median number of medications was 11 (range, 2-28) during the entire study and was highest during chemotherapy (7; range, 2-22). Approximately four-fifths (84%) used HS. A total of 1747 PMIs were identified, and they represented 635 unique PMIs across all 3 timeframes, with most occurring during chemotherapy. Prescription-related PMIs (70%) were the most common type, and they were followed by HS-related (56%) and anticancer treatment-related PMIs (22%). Approximately half of the PMIs (54%) were categorized as moderate interactions, and more than one-third (38%) were categorized as major interactions. Patient use of HS increased from 51% during chemotherapy to 66% after chemotherapy, and this correlated with an increased prevalence of HS PMIs (46% to 60%). HS users were more likely to be at risk for a major PMI than non-HS users (92% vs 70%; P = .038).

CONCLUSIONS

The use of HS remains prevalent among patients with cancer and may place them at risk for PMIs both during chemotherapy and after the completion of treatment.

LAY SUMMARY

This study evaluates the risk of potential medication interactions for patients with breast or prostate cancer undergoing chemotherapy. The results show that patients often use herbs and supplements during treatment. Prescription medications are most often associated with medication interactions, which are followed by herb and supplement-related interactions. More than one-third of potential medication interactions are considered major. Patients should be educated about the risk of herb and supplement-related medication interactions during treatment.

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.

The integrated use of in silico methods for the hepatotoxicity potential of Piper methysticum

Herbal products as supplements and therapeutic intervention have been used for centuries. However, their toxicities are not completely evaluated and the mechanisms are not clearly understood. Dried rhizome of the plant kava (Piper methysticum) is used for its anxiolytic, and sedative effects. The drug is also known for its hepatotoxicity potential. Major constituents of the plant were identified as kavalactones, alkaloids and chalcones in previous studies. Kava hepatotoxicity mechanism and the constituent that causes the toxicity have been debated for decades. In this paper, we illustrated the use of computational tools for the hepatotoxicity of kava constituents. The proposed mechanisms and major constituents that are most probably responsible for the toxicity have been scrutinized. According to the experimental and prediction results, the kava constituents play a substantial role in hepatotoxicity by some means or other via glutathione depletion, CYP inhibition, reactive metabolite formation, mitochondrial toxicity and cyclooxygenase activity. Some of the constituents, which have not been tested yet, were predicted to involve mitochondrial membrane potential, caspase-3 stimulation, and AhR activity. Since Nrf2 activation could be favorable for prevention of hepatotoxicity, we also suggest that these compounds should undergo testing given that they were predicted not to be activating Nrf2. Among the major constituents, alkaloids appear to be the least studied and the least toxic group in general. The outcomes of the study could help to appreciate the mechanisms and to prioritize the kava constituents for further testing.

DARK Classics in Chemical Neuroscience: Kava

Kava (kava kava, Piper methysticum) is a common drug-containing plant in the Pacific islands. Kavalactones, its psychoactive compounds, exert potent central nervous system (CNS) action clinically and in animal models. However, the exact pharmacological profiles and mechanisms of action of kava on the brain and behavior remain poorly understood. Here, we discuss clinical and experimental data on kava psychopharmacology and summarize chemistry and synthesis of kavalactones. We also review its societal impact, drug use and abuse potential, and future perspectives on translational kava research.

Piper Species: A Comprehensive Review on Their Phytochemistry, Biological Activities and Applications

Piper species are aromatic plants used as spices in the kitchen, but their secondary metabolites have also shown biological effects on human health. These plants are rich in essential oils, which can be found in their fruits, seeds, leaves, branches, roots and stems. Some Piper species have simple chemical profiles, while others, such as Piper nigrum, Piper betle, and Piper auritum, contain very diverse suites of secondary metabolites. In traditional medicine, Piper species have been used worldwide to treat several diseases such as urological problems, skin, liver and stomach ailments, for wound healing, and as antipyretic and anti-inflammatory agents. In addition, Piper species could be used as natural antioxidants and antimicrobial agents in food preservation. The phytochemicals and essential oils of Piper species have shown strong antioxidant activity, in comparison with synthetic antioxidants, and demonstrated antibacterial and antifungal activities against human pathogens. Moreover, Piper species possess therapeutic and preventive potential against several chronic disorders. Among the functional properties of Piper plants/extracts/active components the antiproliferative, anti-inflammatory, and neuropharmacological activities of the extracts and extract-derived bioactive constituents are thought to be key effects for the protection against chronic conditions, based on preclinical in vitro and in vivo studies, besides clinical studies. Habitats and cultivation of Piper species are also covered in this review. In this current work, available literature of chemical constituents of the essential oils Piper plants, their use in traditional medicine, their applications as a food preservative, their antiparasitic activities and other important biological activities are reviewed.

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.

Evaluation of How Integrative Oncology Services Are Valued between Hematology/Oncology Patients and Hematologists/Oncologists at a Tertiary Care Center

Evidence regarding opinions on integrative modalities by patients and physicians is lacking. Methods. A survey study was conducted assessing how integrative modalities were valued among hematology/oncology patients and hematologists and oncologists at a major tertiary medical center. Results. 1008 patients and 55 physicians were surveyed. With the exception of support groups, patients valued nutrition services, exercise therapy, spiritual/religious counseling, supplement/herbal advice, support groups, music therapy, and other complimentary medicine services significantly more than physicians (P ≤ 0.05). Conclusion. With the exception of support groups, patients value integrative modalities more than physicians. Perhaps with increasing education, awareness, and acceptance by providers and traditional institutions, integrative modalities could be equally valued between patients and providers. It is possible that increased availability and utilization of integrative oncology modalities at tertiary hospital sites could improve patient satisfaction, quality of life, and other clinical endpoints.

Adverse Effects of Nutraceuticals and Dietary Supplements

Over 70% of Americans take some form of dietary supplement every day, and the supplement industry is currently big business, with a gross of over $28 billion. However, unlike either foods or drugs, supplements do not need to be registered or approved by the US Food and Drug Administration (FDA) prior to production or sales. Under the Dietary Supplement Health and Education Act of 1994, the FDA is restricted to adverse report monitoring postmarketing. Despite widespread consumption, there is limited evidence of health benefits related to nutraceutical or supplement use in well-nourished adults. In contrast, a small number of these products have the potential to produce significant toxicity. In addition, patients often do not disclose supplement use to their physicians. Therefore, the risk of adverse drug-supplement interactions is significant. An overview of the major supplement and nutraceutical classes is presented here, together with known toxic effects and the potential for drug interactions.

Deleterious effects of reactive metabolites

A number of drugs have been withdrawn from the market or severely restricted in their use because of unexpected toxicities that become apparent only after the launch of new drug entities. Circumstantial evidence suggests that, in most cases, reactive metabolites are responsible for these unexpected toxicities. In this review, a general overview of the types of reactive metabolites and the consequences of their formation are presented. The current approaches to evaluate bioactivation potential of new compounds with particular emphasis on the advantages and limitation of these procedures will be discussed. Reasonable reasons for the excellent safety record of certain drugs susceptible to bioactivation will also be explored and should provide valuable guidance in the use of reactive-metabolite assessments when nominating drug candidates for development. This will, in turn, help us to design and bring safer drugs to the market.

Hepatotoxicity Induced by "the 3Ks": Kava, Kratom and Khat

The 3Ks (kava, kratom and khat) are herbals that can potentially induce liver injuries. On the one hand, growing controversial data have been reported about the hepatotoxicity of kratom, while, on the other hand, even though kava and khat hepatotoxicity has been investigated, the hepatotoxic effects are still not clear. Chronic recreational use of kratom has been associated with rare instances of acute liver injury. Several studies and case reports have suggested that khat is hepatotoxic, leading to deranged liver enzymes and also histopathological evidence of acute hepatocellular degeneration. Numerous reports of severe hepatotoxicity potentially induced by kava have also been highlighted, both in the USA and Europe. The aim of this review is to focus on the different patterns and the mechanisms of hepatotoxicity induced by “the 3Ks”, while trying to clarify the numerous aspects that still need to be addressed.

Drug-induced hepatotoxicity of select herbal therapies

The use of herbal botanicals and dietary supplements to treat and alleviate disease symptoms has increased over the past decades, and as a result, more research has been done to study the potential damaging effects of herbal products on the liver and other organs. Although reporting rates vary, cases have been published describing liver damage following herbal therapy. Studies have proposed multiple mechanisms of injury for these herbal preparations, and several potential risk factors have been identified including age, gender, polypharmacy, alcohol consumption, and genetic variability. Ingredients and other constituents often differ among products, and lack of standardization in manufacturing of these formulations makes it difficult to determine causality. The potential for drug-induced liver injury is often not known until the postmarketing period due to less rigorous safety testing and regulations.

Fatal kavalactone intoxication by suicidal intravenous injection

Kavalactones are a group of compounds found in kava, a beverage or extract prepared from the rhizome of the kava plant (Piper methysticum). Traditionally kava extracts have been used for their anxiolytic and sedative properties. Sales of kava extracts were severely restricted or prohibited in European countries in 2002 following several cases of serious hepatotoxicity. Here we report a case where high concentrations of kavalactones and ethanol were detected in post mortem femoral blood. An injection needle with a 10-mL syringe containing 7.5 mL of slightly yellowish liquid was found next to the victim, and there were numerous needle prints on both lower arms following the venous tracks. No evidence of other cause of death was found in the medico-legal investigation. The case was therefore classified as suicide using an injection of kavalactones intravenously together with alcohol poisoning.

Flavokawains B and C, melanogenesis inhibitors, isolated from the root of Piper methysticum and synthesis of analogs

The ethanolic extract of the root of Piper methysticum was found to inhibit melanogenesis in MSH-activated B16 melanoma cells. Flavokawains B and C were isolated from this extract based on their anti-melanogenesis activity and found to inhibit melanogenesis with IC50 values of 7.7μM and 6.9μM, respectively. Flavokawain analogs were synthesized through a Claisen-Schmidt condensation of their corresponding acetophenones and benzaldehydes and were evaluated in terms of their tyrosinase inhibitory and anti-melanogenesis activities. Compound 1b was the most potent of these with an IC50 value of 2.3μM in melanogenesis inhibition assays using MSH-activated B16 melanoma cells.

Herbal Insomnia Medications that Target GABAergic Systems: A Review of the Psychopharmacological Evidence

Insomnia is a common sleep disorder which is prevalent in women and the elderly. Current insomnia drugs mainly target the γ-aminobutyric acid (GABA) receptor, melatonin receptor, histamine receptor, orexin, and serotonin receptor. GABA_A receptor modulators are ordinarily used to manage insomnia, but they are known to affect sleep maintenance, including residual effects, tolerance, and dependence. In an effort to discover new drugs that relieve insomnia symptoms while avoiding side effects, numerous studies focusing on the neurotransmitter GABA and herbal medicines have been conducted. Traditional herbal medicines, such as Piper methysticum and the seed of Zizyphus jujuba Mill var. spinosa, have been widely reported to improve sleep and other mental disorders. These herbal medicines have been applied for many years in folk medicine, and extracts of these medicines have been used to study their pharmacological actions and mechanisms. Although effective and relatively safe, natural plant products have some side effects, such as hepatotoxicity and skin reactions effects of Piper methysticum. In addition, there are insufficient evidences to certify the safety of most traditional herbal medicine. In this review, we provide an overview of the current state of knowledge regarding a variety of natural plant products that are commonly used to treat insomnia to facilitate future studies.

Dietary feeding of Flavokawain A, a Kava chalcone, exhibits a satisfactory safety profile and its association with enhancement of phase II enzymes in mice

Flavokawain A (FKA), a major chalcone in the Kava plant, has recently demonstrated promising anti-cancer activities. A systematic evaluation of FKA's safety profile has not been reported before. In this study, male FVB/N mice were fed with an AIN-76A diet or AIN-76A diet supplemented with 0.6% (6 g/kg food) FKA or 0.6% commercial kava root extract (KRE) for three weeks. Dietary feeding of FKA did not affect food consumption and body weight. Histopathological examination of liver, kidney, colon, lung, heart, spleen, and thymus revealed no signs of FKA-induced toxicity. Biochemical serum analysis and histological examination confirmed normal organ function in FKA-treated mice. The cytotoxicity profile showed FKA had minimal side effects on bone marrow and small intestinal epithelial cells compared with Adriamycin. In addition, oral feeding of FKA increased activities of both glutathione S-transferase and quinone reductase in the liver, lung, prostate and bladder tissues of mice. In comparison, dietary feeding of 0.6% KRE increased liver/body weight ratio and decreased spleen, thymus, and testis/body weight ratios, as well as induced nodular proliferation in liver tissues. Therefore, dietary feeding FKA showed no adverse effects on major organ function and homeostasis in mice, suggesting the potential of FKA for chemoprevention study of human cancers.

The flavokawains: uprising medicinal chalcones

Plant-based compounds have been in the spotlight in search of new and promising drugs. Flavokawain A, B and C are naturally occurring chalcones that have been isolated from several medicinal plants; namely the piper methysticum or commercially known as the kava-kava. Multiple researches have been done to evaluate the bioactivities of these compounds. It has been shown that all three flavokawains may hold promising anti-cancer effects. It has also been revealed that both flavokawain A and B are involved in the induction of cell cycle arrest in several cancer cell lines. Nevertheless, flavokawain B was shown to be more effective in treating in vitro cancer cell lines as compared to flavokawain A and C. Flavokawain B also exerts antinociceptive effects as well as anti-inflammation properties. This mini-review attempts to discuss the biological properties of all the flavokawains that have been reported.

Kava in the treatment of generalized anxiety disorder: a double-blind, randomized, placebo-controlled study

Kava (Piper methysticum) is a plant-based medicine, which has been previously shown to reduce anxiety. To date, however, no placebo-controlled trial assessing kava in the treatment of generalized anxiety disorder (GAD) has been completed. A total of 75 participants with GAD and no comorbid mood disorder were enrolled in a 6-week double-blind trial of an aqueous extract of kava (120/240 mg of kavalactones per day depending on response) versus placebo. γ-Aminobutyric acid (GABA) and noradrenaline transporter polymorphisms were also analyzed as potential pharmacogenetic markers of response. Reduction in anxiety was measured using the Hamilton Anxiety Rating Scale (HAMA) as the primary outcome. Intention-to-treat analysis was performed on 58 participants who met inclusion criteria after an initial 1 week placebo run-in phase. Results revealed a significant reduction in anxiety for the kava group compared with the placebo group with a moderate effect size (P = 0.046, Cohen d = 0.62). Among participants with moderate to severe Diagnostic and Statistical Manual of Mental Disorders-diagnosed GAD, this effect was larger (P = 0.02; d = 0.82). At conclusion of the controlled phase, 26% of the kava group were classified as remitted (HAMA ≤ 7) compared with 6% of the placebo group (P = 0.04). Within the kava group, GABA transporter polymorphisms rs2601126 (P = 0.021) and rs2697153 (P = 0.046) were associated with HAMA reduction. Kava was well tolerated, and aside from more headaches reported in the kava group (P = 0.05), no other significant differences between groups occurred for any other adverse effects, nor for liver function tests. Standardized kava may be a moderately effective short-term option for the treatment of GAD. Furthermore, specific GABA transporter polymorphisms appear to potentially modify anxiolytic response to kava.

Suppression of iNOS and COX-2 expression by flavokawain A via blockade of NF-κB and AP-1 activation in RAW 264.7 macrophages

Flavokawain A, a major constituent of chalcones derived from kava extracts, exerts various biological activities such as anti-tumor activities. In this study, we examined the suppressive effect of flavokawain A on LPS-induced expression of pro-inflammatory mediators and the molecular mechanisms responsible for these activities in the murine macrophages. Flavokawain A significantly suppressed expression of iNOS and COX-2, as well as the subsequent production of NO and PGE2 in the LPS-stimulated RAW 264.7 cells. Flavokawain A significantly inhibited LPS-induced activation of NF-κB and AP-1 signaling pathways. In addition, flavokawain A inhibited activation of JNK and p38 MAPK which was responsible for expression of iNOS and COX-2 in the LPS-stimulated RAW 264.7 cells. Furthermore, flavokawain A suppressed LPS-induced expression of pro-inflammatory cytokines, such as TNF-α, IL-1β and IL-6. These results suggest that flavokawain A may exert anti-inflammatory responses by suppressing LPS-induced expression of pro-inflammatory mediators via blockage of NF-κB-AP-1-JNK/p38 MAPK signaling pathways in the murine macrophages.

Kava for the treatment of generalized anxiety disorder RCT: analysis of adverse reactions, liver function, addiction, and sexual effects

Presently, little is known about a number issues concerning kava (Piper methysticum), including (i) whether kava has any withdrawal or addictive effects; (ii) if genetic polymorphisms of the cytochrome (CYP) P450 2D6 liver enzyme moderates any potential adverse effects; and (iii) if medicinal application of kava has any negative or beneficial effect on sexual function and experience. The study design was a 6-week, double-blind, randomized controlled trial (n = 75) involving chronic administration of kava (one tablet of kava twice per day; 120 mg of kavalactones per day, titrated in non-response to two tablets of kava twice per day; 240 mg of kavalactones) or placebo for participants with generalized anxiety disorder. Results showed no significant differences across groups for liver function tests, nor were there any significant adverse reactions that could be attributed to kava. No differences in withdrawal or addiction were found between groups. Interesting, kava significantly increased female's sexual drive compared to placebo (p = 0.040) on a sub-domain of the Arizona Sexual Experience Scale (ASEX), with no negative effects seen in males. Further, it was found that there was a highly significant correlation between ASEX reduction (improved sexual function and performance) and anxiety reduction in the whole sample.

Kavalactones and the endocannabinoid system: the plant-derived yangonin is a novel CB₁ receptor ligand

To investigate the possible interactions between kavalactone-based molecules and proteins of the endocannabinoid system and provide novel and synthetically accessible structural scaffolds for the design of cannabinoid receptor ligands sharing pharmacological properties with kavapyrones, a preliminary SAR analysis was performed on five commercially available natural kavalactones and nine kavalactone-analogues properly synthesized. These compounds were investigated for assessing their cannabinoid receptor binding affinity and capability of inhibiting the activity of the two major metabolic enzymes of the endocannabinoid system, fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL). Among the molecules tested, only yangonin exhibited affinity for the human recombinant CB₁ receptor with a K(i)=0.72 μM and selectivity vs. the CB₂ receptor (K(i)>10 μM). None of the compounds exhibited strong inhibitory effects on the two enzymes analyzed. The CB₁ receptor affinity of yangonin suggests that the endocannabinoid system might contribute to the complex human psychopharmacology of the traditional kava drink and the anxiolytic preparations obtained from the kava plant.

Lung Tumorigenesis Suppressing Effects of a Commercial Kava Extract and Its Selected Compounds in A/J Mice

Lung cancer is the most deadly malignancy in the US. Chemoprevention is potentially a complementary approach to smoking cessation for lung cancer control. Recently, we reported that a commercially available form of kava extract significantly inhibits 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and benzo(a)pyrene (BaP)-induced lung tumorigenesis in A/J mice at a dose of 10 mg per gram diet. In the present study, we examined the dose-dependent lung tumor inhibitory activities of kava and investigated potential active constituent(s). Mice treated with carcinogen alone contained 12.1±5.8 lung adenomas per mouse 22 weeks after final carcinogen administration. Mice that were fed diets containing kava at dosages of 1.25, 2.5, 5, and 10 mg/g of diet had 8.4±3.5, 6.6±3.5, 4.3±2.4, and 3.8±2.3 lung adenomas per mouse, respectively. This corresponds to a reduction of 31%, 46%, 65% and 69% in tumor multiplicity, which were all statistically significant (p < 0.05). Analyses of lung adenoma tissues derived from kava-treated animals revealed that kava significantly inhibited adenoma cell proliferation while it had no detectable effect on cell death, indicating that kava primarily suppressed lung tumorigenesis in A/J mice via inhibition of cell proliferation. Flavokawains A, B, and C, three chalcone-based components from kava, demonstrated greatly reduced chemopreventive efficacies even at concentrations much higher than their natural abundance, suggesting that they alone were unlikely to be responsible for kava's chemopreventive activity. Kava at all dosages and treatment regimens did not induce detectable adverse effects, particularly with respect to liver. Specifically, kava treatment showed no effect on liver integrity indicator enzymes or liver weight, indicating that kava may be potentially safe for long-term chemopreventive application.

Use of complementary and alternative medicine in a large sample of anxiety patients

OBJECTIVE

To examine a large sample of patients with anxiety and the association between types of complementary and alternative treatments that were used, demographic variables, diagnostic categories, and treatment outcomes.

METHOD

Cross-sectional and longitudinal survey during the Coordinated Anxiety Learning and Management (CALM) study that assessed this intervention against the Usual Care in a sample of patients with anxiety recruited from primary care. Interviewer-administered questionnaires via a centralized telephone survey by blinded assessment raters. The interviews were done at baseline, 6, 12, and 18 months of the study. A total of 1004 adults ages 18-75 who met DSM-IV criteria for Generalized Anxiety Disorder (GAD), Panic Disorder, Social Anxiety Disorder, or Post-Traumatic Stress Disorder. We assessed medication/herbal use, the use of any alternative therapies, and combined Complementary and Alternative Medicine (CAM) use.

RESULTS

We found an extensive (43%) use of a variety of CAM treatments that is consistent with previous study results in populations with anxiety. Only a few significant demographic or interventional characteristics of CAM users were found. Users most often had a diagnosis of GAD, were older, more educated, and had two or more chronic medical conditions. CAM users who had a 50% or more drop in anxiety scores over 18 months were less likely to report continued use of alternative therapies.

CONCLUSIONS

The study confirms the importance of awareness of CAM use in this population for possible interference with traditional first-line treatments of these disorders, but also for finding the best integrative use for patients who require multiple treatment modalities.

Methysticin and 7,8-dihydromethysticin are two major kavalactones in kava extract to induce CYP1A1

Kava is a plant traditionally used for making beverages in Pacific Basin countries and has been used for the treatment of nervous disorders in the United States. The pharmacological activity of kava is achieved through kavalactones in kava extract, which include kawain, 7,8-dihydrokawain, yangonin, 5,6-dehydrokawain, methysticin, and 7,8-dihydromethysticin. Recent studies have shown that kava extract induces hepatic CYP1A1 enzyme; however, the mechanisms of CYP1A1 induction have not been elucidated, and the kavalactones responsible for CYP1A1 induction have not yet been identified. Using a combination of biochemical assays and molecular docking tools, we determined the functions of kava extract and kavalactones and delineated the underlying mechanisms involved in CYP1A1 induction. The results showed that kava extract displayed a concentration-dependent effect on CYP1A1 induction. Among the six major kavalactones, methysticin triggered the most profound inducing effect on CYP1A1 followed by 7,8-dihydromethysticin. The other four kavalactones (yangonin, 5,6-dehydrokawain, kawain, and 7,8-dihydrokawain) did not show significant effects on CYP1A1. Consistent with the experimental results, in silico molecular docking studies based on the aryl hydrocarbon receptor (AhR)-ligand binding domain homology model also revealed favorable binding to AhR for methysticin and 7,8-dihydromethysticin compared with the remaining kavalactones. Additionally, results from a luciferase gene reporter assay suggested that kava extract, methysticin, and 7,8-dihydromethysticin were able to activate the AhR signaling pathway. Moreover, kava extract-, methysticin-, and 7,8-dihydromethysticin-mediated CYP1A1 induction was blocked by an AhR antagonist and abolished in AhR-deficient cells. These findings suggest that kava extract induces the expression of CYP1A1 via an AhR-dependent mechanism and that methysticin and 7,8-dihydromethysticin contribute to CYP1A1 induction. The induction of CYP1A1 indicates a potential interaction between kava or kavalactones and CYP1A1-mediated chemical carcinogenesis.

Proposal for a kava quality standardization code

Rare cases of hepatotoxicity emerged with the use of kava drugs and dietary supplements prepared from rhizomes and roots of the South Pacific plant kava (Piper methysticum). Their psychoactive, anxiolytic, relaxing, and recreational ingredients are the kavalactones kavain, dihydrokavain, methysticin, dihydromethysticin, yangonin, and desmethoxyyangonin, but there is little evidence that these kavalactones or the non-kavalactones pipermethystine and flavokavain B are the culprits of the adverse hepatic reactions. It rather appears that poor quality of the kava material was responsible for the liver toxicity. Analysis of existing kava quality standardizations with focus on chemical, agricultural, manufacturing, nutritional, regulatory, and legislation backgrounds showed major shortcomings that could easily explain quality problems. We therefore suggest a uniform, internationally accepted device for kava quality standardizations that are in the interest of the consumers because of safety reasons and will meet the expectations of kava farmers, pharmaceutical manufacturers, regulators of agencies, and legislators. The initial step resides in the establishment of Pan-Pacific kava quality legislation as an important part of the proposed Kava Quality Standardization Code. In conclusion, a sophisticated approach to establish kava quality standardizations is needed for safe human use of kava as relaxing traditional beverages, the anxiolytic drugs, and recreational dietary supplements.

Constituents in kava extracts potentially involved in hepatotoxicity: a review

Aqueous kava root preparations have been consumed in the South Pacific as an apparently safe ceremonial and cultural drink for centuries. However, several reports of hepatotoxicity have been linked to the consumption of kava extracts in Western countries, where mainly ethanolic or acetonic extracts are used. The mechanism of toxicity has not been established, although several theories have been put forward. The composition of the major constituents, the kava lactones, varies according to preparation method and species of kava plant, and thus, the toxicity of the individual lactones has been tested in order to establish whether a single lactone or a certain composition of lactones may be responsible for the increased prevalence of kava-induced hepatotoxicity in Western countries. However, no such conclusion has been made on the basis of current data. Inhibition or induction of the major metabolizing enzymes, which might result in drug interactions, has also gained attention, but ambiguous results have been reported. On the basis of the chemical structures of kava constituents, the formation of reactive metabolites has also been suggested as an explanation of toxicity. Furthermore, skin rash is a side effect in kava consumers, which may be indicative of the formation of reactive metabolites and covalent binding to skin proteins leading to immune-mediated responses. Reactive metabolites of kava lactones have been identified in vitro as glutathione (GSH) conjugates and in vivo as mercapturates excreted in urine. Addition of GSH to kava extracts has been shown to reduce cytotoxicity in vitro, which suggests the presence of inherently reactive constituents. Only a few studies have investigated the toxicity of the minor constituents present in kava extract, such as pipermethystine and the flavokavains, where some have been shown to display higher in vitro cytotoxicity than the lactones. To date, there remains no indisputable reason for the increased prevalence of kava-induced hepatotoxicity in Western countries.

Toxicokinetics of kava

Kava is traditionally consumed by South Pacific islanders as a drink and became popular in Western society as a supplement for anxiety and insomnia. Kava extracts are generally well tolerated, but reports of hepatotoxicity necessitated an international reappraisal of its safety. Hepatotoxicity can occur as an acute, severe form or a chronic, mild form. Inflammation appears to be involved in both forms and may result from activation of liver macrophages (Kupffer cells), either directly or via kava metabolites. Pharmacogenomics may influence the severity of this inflammatory response.

Neurocognitive effects of kava (Piper methysticum): a systematic review

RATIONALE

Kava (Piper methysticum) elicits dose-dependent psychotropic effects and thus may potentially deleteriously affect cognitive performance. Clinical trials have assessed the effects of kava on cognition, however, to our knowledge no systematic review has been conducted in this area.

OBJECTIVE

To systematically review the effects of kava on cognition, providing an analysis of the individual study's methodological quality, results and effect sizes.

METHODS

A systematic review was conducted of publications up to June 15th 2010, using the electronic databases MEDLINE, PsychINFO, CINAHL, Web of Science and The Cochrane Library. The search criteria involved kava and cognition related terms, e.g. memory and attention.

RESULTS

Ten human clinical trials met inclusion criteria (acute n = 7, chronic n = 3). One acute study found that kava significantly improved visual attention and working memory processes while another found that kava increased body sway. One chronic study found that kava significantly impaired visual attention during high-cognitive demand. Potential enhanced cognition may be attributed to the ability of kava to inhibit re-uptake of noradrenaline in the pre-frontal cortex, while increased body sway may be due to GABA pathway modulation.

CONCLUSIONS

The majority of evidence suggests that kava has no replicated significant negative effects on cognition.

Kava hepatotoxicity: comparative study of two structured quantitative methods for causality assessment

BACKGROUND AND OBJECTIVE

Ingestion of the medicinal herb kava has been associated with hepatotoxicity. We aimed to compare two different quantitative methods of causality assessment of patients with assumed hepatotoxicity by the herb.

METHODS

We assessed causality in 26 patients from Germany and Switzerland, using two structured quantitative analytical methods: the system of Maria and Victorino (MV) and that of the Council for International Organizations of Medical Sciences (CIOMS). In all 26 patients, regulatory ad hoc evaluation had suggested a causal relationship between liver disease and kava use.

RESULTS AND DISCUSSION

Assessment with the MV scale resulted in no or low graded causality for kava in the 26 patients with liver disease. Causality was probable (n=1), possible (n=2), unlikely (n=7), and excluded (n=16). Causality for kava was more evident with the CIOMS scale: highly probable (n=1), probable (n=2), possible (n=6), unlikely (n=2) and excluded (n=15). However, the results of both quantitative causality assessments are not supportive for most of the regulatory ad hoc causality assessments of the 26 patients.

CONCLUSION

Grades of causality for suspected hepatotoxicity by kava were much lower when evaluated by structured quantitative causality assessment scales than by regulatory ad hoc judgements. The quantitative CIOMS scale is the preferable tool for causality assessment of spontaneous reports of hepatotoxcity involving kava.

Kava: a comprehensive review of efficacy, safety, and psychopharmacology

OVERVIEW

Kava (Piper methysticum) is a South Pacific psychotropic plant medicine that has anxiolytic activity. This effect is achieved from modulation of GABA activity via alteration of lipid membrane structure and sodium channel function, monoamine oxidase B inhibition, and noradrenaline and dopamine re-uptake inhibition. Kava is available over the counter in jurisdictions such as the USA, Australia and New Zealand. Due to this, a review of efficacy, safety and clinical recommendations is advised.

OBJECTIVE

To conduct a comprehensive review of kava, in respect to efficacy, psychopharmacology, and safety, and to provide clinical recommendations for use in psychiatry to treat generalized anxiety disorder (GAD).

METHODS

A review was conducted using the electronic databases MEDLINE, CINAHL, PsycINFO and the Cochrane Library during mid 2010 of search terms relating to kava and GAD. A subsequent forward search was conducted of key papers using Web of Science cited reference search.

RESULTS

The current weight of evidence supports the use of kava in treatment of anxiety with a significant result occurring in four out of six studies reviewed (mean Cohen's d = 1.1). Safety issues should however be considered. Use of traditional water soluble extracts of the rhizome (root) of appropriate kava cultivars is advised, in addition to avoidance of use with alcohol and caution with other psychotropic medications. Avoidance of high doses if driving or operating heavy machinery should be mandatory. For regular users routine liver function tests are advised.

CONCLUSIONS

While current evidence supports kava for generalized anxiety, more studies are required to assess comparative efficacy and safety (on the liver, cognition, driving, and sexual effects) versus established pharmaceutical comparators.

Herbs in hemato-oncological care: an evidence-based review of data on efficacy, safety, and drug interactions

Herbal remedies are clearly a complementary and alternative modality used frequently by patients with hemato-oncological neoplasias during the course of their specific treatment. This review focuses on the potential safety and efficacy of herbs which are either used often or even on a daily basis by patients with hematological malignancies or indicated in the herbal pharmacopeias utilized by various traditional systems of medicine, in order to improve the well-being of patients with these cancers. Traditional medicine worldwide is a source for ongoing laboratory research related to the activity of herbs on cultured cell lines derived from patients with leukemia, lymphoma, and myeloma. Although the number of clinical studies in the field of hemato-oncology is limited, there appears to be potential efficacy in studies of mistletoe (Viscum album), green tea, Indian and Middle-Eastern spices, and some traditional Chinese, American, and European herbs. In addition to the potential efficacy of herbs, safety issues are also reviewed here, particularly, the documented and potential side effects, herb-drug interactions, and matters of quality control. Based on the above issues, the authors suggest enhancing doctor-patient communication regarding herbal use by adopting a patient-centered attitude based on scientific perspective.

Kavalactones Yangonin and Methysticin induce apoptosis in human hepatocytes (HepG2) in vitro

While cases of severe kava hepatotoxicity have been reported, studies examining the toxicity of individual kavalactones are limited. The present study examined the in vitro hepatotoxicity of kavain, methysticin and yangonin on human hepatocytes (HepG2) and the possible mechanism(s) involved. Cytotoxicity was assessed using lactate dehydrogenase (LDH) and ethidium bromide (EB) assays. The mode of cell death was analysed with acridine orange/ethidium bromide dual staining with fluorescence microscopy. Glutathione oxidation was measured using the ortho-phthalaldehyde (OPT) fluorescence assay. Kavain had minimal cytotoxicity, methysticin showed moderate concentration-dependent toxicity and yangonin displayed marked toxicity with ~ 40% reduction in viability in the EB assay. Acridine orange/ethidium bromide staining showed the predominant mode of cell death was apoptosis rather than necrosis. No significant changes were observed in glutathione levels, excluding this as the primary mechanism of cell death in this model. Further studies may elucidate the precise apoptotic pathways responsible and whether toxic kavalactone metabolites are involved.