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At least 19 recordsLinked to original sources
PubMed1998

Inhibition of platelet MAO-B by kava pyrone-enriched extract from Piper methysticum Forster (kava-kava).

Kava-kava, a psychoactive beverage, induces relaxation, improves social interaction, promotes sleep and plays an important role in the sociocultural life in the islands of the South Pacific. On the other hand, standardized extracts of kava-kava roots are used for the therapy of anxiety, tension and restlessness. Kava pyrones, the major constituents of kava kava, are generally considered to be responsible for the pharmacological activity in humans and animals. To obtain more information on the mechanisms by which kava-kava exerts psychotropic properties we investigated the in vitro effects of kava-kava extract and pure synthetic kava pyrones on human platelet MAO-B, in comparison to amitriptyline, imipramine and brofaromine. Kava-kava extract was found to be a reversible inhibitor of MAO-B in intact platelets (IC50 24 microM) and disrupted platelet homogenates (IC50 1.2 microM). Structural differences of kava pyrones resulted in a different potency of MAO-B inhibition. The order of potency was desmethoxyyangonin > (+/-)-methysticin > yangonin > (+/-)-dihydromethysticin > (+/-)- dihydrokavain > (+/-)-kavain. The two most potent kava pyrones, desmethoxyyangonin and (+/-)-methysticin displayed a competetive inhibition pattern with mean Ki 0.28 microM and 1.14 microM respectively. The inhibition of MAO-B by kava pyrone-enriched extracts might be an important mechanism for their psychotropic activity.

Amitriptyline↗
PubMed1998

Piper methysticum (kava kava).

Piper methysticum (kava kava) is a plant native to the Pacific Island region, and has been used ceremonial for thousands of years. The active ingredients are a group of substances know as kava lactones (AKA kava pyrones). Four lactones in kava have been found to have significant analgesic and anesthetic effects via non-opiate pathways. Kava's most popular application is as a natural anxiolytic, comparing favorably in several studies to a number prescription medications, including benzodiazepines. CNS effects seem to be mediated by several mechanisms. Studies have been conflicting regarding its GABA-receptor-binding capacity, although this has been found to occur in some studies. In vitro kava has been found to block norepinephrine uptake. It also has some anti-convulsant capabilities, which appear to be mediated by Na+ channel receptor sites. The therapeutic dosage is in the range of 50-70 mg kava lactones three times daily. The most common side effect, usually seen only with long-term, heavy usage of the herb, is a scaly skin rash called "kava dermopathy." It has also been know to potentiate other medications such as barbiturates and Xanax.

Anti-Anxiety Agents↗
PubMed1998

[Kava-kava preparations--alternative anxiolytics].

Since Cook's world cruises (1772-1775) there is written evidence of the use of kava-kava by the inhabitants of the Pacific Islands. In last decades kava-kava, an extract of the plant Piper methysticum was used in several European countries (drugs like Laitan, Antares, Viocava, Mosaro etc.). In the presented paper the authors describe the pharmacology, toxicology and pharmacokinetics of the active compounds of kava-kava the kavapyrones. The discussion concerning the therapeutic value of kavapyrones ends with the conclusion of the authors, that kava-kava may be a useful alternative for synthetic anxiolytics.

Animals↗
PubMedDate not supplied

Kava-kava extract in anxiety disorders: an outpatient observational study.

Fifty-two outpatients suffering from anxiety of nonpsychotic origin were included in an observational study of a kava-kava preparation. Drug efficacy was evident on measures of a global improvement scale, with 42 patients (80.8%) rating treatment as "very good" or "good". Adverse events were rare. These results support kava-kava extract as an effective and safe alternative to antidepressants and tranquilizers in anxiety disorder without the tolerance problems associated with benzodiazepines.

Adult↗
PubMed1997

Kava-kava extract WS 1490 versus placebo in anxiety disorders--a randomized placebo-controlled 25-week outpatient trial.

101 outpatients suffering from anxiety of non-psychotic origin (DSM-III-R criteria: agoraphobia, specific phobia, generalized anxiety disorder, and adjustment disorder with anxiety) were included in a 25-week multicenter randomized placebo-controlled double-blind trial with WS 1490, a special extract of kava-kava. In the main outcome criterion, the Hamilton Anxiety Scale (HAMA), there was a significant superiority of the test drug starting from week 8 on. WS 1490 was also found to be superior with respect to the secondary outcome variables. HAMA subscores somatic and psychic anxiety, Clinical Global Impression, Self-Report Symptom Inventory-90 Items revised, and Adjective Mood Scale. Adverse events were rare and distributed evenly in both groups. These results support WS 1490 as a treatment alternative to tricyclic antidepressants and benzodiazepines in anxiety disorders, with proven long-term efficacy and none of the tolerance problems associated with tricyclics and benzodiazepines.

Anti-Anxiety Agents↗
PubMed1998

Over-the-counter psychotropics: a review of melatonin, St John's wort, valerian, and kava-kava.

Use and availability of alternative healthcare products have revived in the last few years. The prevalence of supplement use in the United States is largely unknown but is thought to be widespread. In this article, four of the common substances used to treat emotional problems are reviewed. The plant or substance description, clinical indications, evidence of therapeutic efficacy, mechanisms of therapeutic actions, dosages and regimens, different commercially available preparations, and adverse effects and toxicities are described for melatonin, St John's wort, valerian, and kava-kava. That a product is "natural" does not mean that it is either safe or effective. Many supplements are potent drugs that lack sufficient data on safety, dose-response relationships, drug interactions, and purity.

Anti-Anxiety Agents↗
PubMed1988

Effects of the heavy usage of kava on physical health: summary of a pilot survey in an aboriginal community.

Health status was assessed in 39 kava users and 34 non-users in a coastal Aboriginal community in Arnhem Land. Twenty (27%) respondents were very heavy (mean consumption, 440 g/week) users of kava; 15 (21%) respondents were heavy (310 g/week) users of kava and four (5%) respondents were occasional (100 g/week) users of kava. Kava users were more likely to complain of poor health and a "puffy" face, and were more likely to have a typical scaly rash, and slightly-increased patellar reflexes. Very heavy users of kava were 20% underweight and their levels of gamma-glutamyl transferase were increased greatly. Albumin, plasma protein, urea and bilirubin levels were decreased in kava users, and high-density lipoprotein cholesterol levels were increased. Kava users were more likely to show haematuria, and to have urine which was poorly acidified and of low specific gravity. The use of kava was also associated with an increased red-cell volume, with a decreased platelet volume and with a decreased lymphocyte count. Shortness of breath in kava users was associated with tall P waves on a resting electrocardiogram, which provided suggestive evidence of pulmonary hypertension. In common with other Aboriginal communities, there was evidence of decreased lung volumes, a high carriage rate of hepatitis B surface antigen, and of other morbidity that was unrelated to the use of kava. On the basis of these findings, there is a strong rationale for urgent social action to improve health in Aboriginal communities and, in particular, to reduce the consumption of kava and to improve the nutritional status of kava users.

Adolescent↗
PubMed1994

Kava dermopathy.

Kava is a psychoactive beverage used ceremonially for thousands of years by Pacific Islanders. Kava is made from the root of the pepper plant, Piper methysticum, found in Polynesia, Melanesia, and Micronesia. The beverage is a nonfermented depressant with complex neuropharmacologic properties that causes a tranquil state of intoxication. Kava also affects the skin, causing a peculiar scaly eruption. The cutaneous effects were first reported by members of Captain James Cook's Pacific expeditions, but they have never been described in dermatologic literature. Heavy kava drinkers acquire a reversible ichthyosiform eruption, kava dermopathy. The cause is unknown but may relate to interference with cholesterol metabolism. Today kava is used across the Pacific in both traditional ceremonies and informal social events. In Western nations, kava is sold as a relaxant by health food stores. This article explores the history of kava dermopathy from Cook's early reports to its presence today.

Beverages↗
PubMed2000

Efficacy of kava extract for treating anxiety: systematic review and meta-analysis.

Synthetic anxiolytic drugs are effective for treating anxiety, but they are burdened with adverse effects. Constraints on resources and time often render therapies such as psychologic interventions impracticable. Thus, an effective oral medication with few adverse effects would be a welcome addition to the therapeutic repertoire. This systematic review and meta-analysis was aimed at assessing the evidence for or against the efficacy of kava extract as a symptomatic treatment for anxiety. Systematic literature searches were performed in the computerized databases MEDLINE, EMBASE, BIOSIS, AMED, CISCOM, and the Cochrane Library (all from their respective inception to June 1998). The search terms used were kava, kawa, kavain, Piper methysticum, and Rauschpfeffer (German term for Piper methysticum). Experts on the subject were contacted to provide further information. There were no restrictions regarding the language of publication. Double-blind, randomized, placebo-controlled trials of oral kava extract for the treatment of anxiety were included. All publications were blinded before assessment by a person not involved in the study. Data were extracted in a standardized, predefined fashion independently by the two reviewers. The methodologic quality of all trials was assessed. Superiority of kava extract over placebo was suggested by all seven reviewed trials. The meta-analysis of three trials suggests a significant difference in the reduction of the total score on the Hamilton Rating Scale for Anxiety in favor of kava extract (weighted mean difference, 9.69; 95% confidence interval, 3.54-15.83). These data imply that kava extract is superior to placebo as a symptomatic treatment for anxiety. Therefore, kava extract is an herbal treatment option for anxiety that is worthy of consideration.

Anti-Anxiety Agents↗
PubMed1991

Development of tolerance to kava in mice.

1. The development of tolerance to the aqueous extract of kava, and to the lipid soluble extract (kava resin) was tested in mice. 2. Tolerance to the unknown pharmacologically active ingredient(s) developed very rapidly, given parenterally, in the aqueous extract. A minimally effective daily dose (50 mg/kg) of the aqueous extract for 3 days was sufficient to produce tolerance to a test dose of 150 mg/kg, which is close to the ED50. As tolerance was evident at the first test period it can be assumed to be physiological tolerance. 3. Kava resin decreased spontaneous motility and caused a loss of muscle control. A minimally effective daily dose of kava resin (100 mg/kg) did not produce tolerance to the above effects of a weekly test dose of kava resin (166 mg/kg) within 7 weeks. In a further experiment the dose was raised to 150 mg/kg twice daily and this schedule caused partial tolerance to occur within 3 weeks, but very little further tolerance developed over the ensuing 2-week period. 4. To try to induce learned (behaviourally acquired) tolerance a dose of 166 mg/kg kava resin was injected daily and animals were tested each day while under the influence of the drug. However, even under these conditions, there was no tolerance evident within 3 weeks, when the experiment was terminated. 5. It appears difficult to induce the development of physiological or learned tolerance to kava resin in mice.

Animals↗
PubMed1992

Kava pyrones and resin: studies on GABAA, GABAB and benzodiazepine binding sites in rodent brain.

Kava, an intoxicating beverage prepared from the pepper plant Piper methysticum, is widely consumed by the indigenous peoples in the islands of the South Pacific. As the first of a series of studies on the neuropharmacological interactions of kava with CNS receptors we tested purified pyrones and kava resin for activity on GABA and benzodiazepine binding sites in rat and mouse brain membranes. Only weak activity was observed on GABAA binding sites in washed synaptosomal membranes prepared from rat brain and this was abolished by extraction of the membranes with Triton X-100, suggesting that lipid soluble components were involved. No effects were observed on GABAB binding sites in rat brain membranes in vitro. Kava resin and pyrones exerted some weak effects on benzodiazepine binding in vitro but this did not correlate with pharmacological activity. In addition, in ex vivo studies, no effects were observed on [3H]diazepam binding to brain membranes prepared from mice in which selected kava constituents were injected intraperitoneally, whereas similarly administered diazepam (5 mg/kg) inhibited [3H]diazepam binding by greater than 95%. Similar lack of activity was observed in in vivo binding studies; injection of kava resin failed to influence the CNS binding of the benzodiazepine-receptor ligand [3H]Ro15-1788 injected into mice prior to sacrifice. The pharmacological activities of kava resin and pyrones do not appear to be explained by any significant interaction with GABA or benzodiazepine binding sites.

Animals↗
PubMedDate not supplied

Effect of aqueous and lipid-soluble extracts of kava on the conditioned avoidance response in rats.

The aqueous, pyrone-free extract from kava (Piper methysticum) and the lipid-soluble extract (kava resin) were tested for their effect on amphetamine-induced hypermotility in mice and on conditioned avoidance response behavior in rats in a shelf-jump apparatus. Both kava extracts reduced amphetamine-induced hypermotility. Aqueous kava extract in i.p. doses of 30 mg/kg to 500 mg/kg had no effect on conditioned avoidance responses. At or below 100 mg/kg i.p. kava resin also failed to modify the number of conditioned avoidance responses obtained. However, 125 mg/kg of resin significantly reduced the number of conditioned avoidance responses by 18%. Increasing the dose of kava to 150 mg/kg caused ataxia and sedation which was so marked that a modified protocol was necessary. Only a marginally greater effect on conditioned avoidance response was obtained under these conditions. The effect of kava extract was slight compared to that of the standard antipsychotic drugs chlorpromazine and haloperidol in our procedure.

Amphetamine↗
PubMed1996

[Hematogenous contact eczema cause by phytogenic drugs exemplified by kava root extract].

The increasing promotion of herbal drugs may lead to allergic problems. A case of systemic contact-type dermatitis after oral administration of kava extract illustrates this special problem. The kava plant is a member of the black pepper family; an intoxicant beverage prepared from the roots of this plant is used ceremonially by many traditional societies of the Southern Pacific. The beverage induces relaxation, enhances a sense of sociability and promotes sleep. These effects are utilized in herbal drugs containing kava, which are sold for insomnia, nervousness and depression. The ichthyosiform kava dermopathy is a well-known side effect of excessive use of kava; in this case report we describe an acute allergic side-effect of kava extract.

Administration, Oral↗