Kava or kava-kava (Piper methysticum) (Piper: Latin for 'pepper', methysticum: (Latinized) Greek for 'intoxicating') is a crop of the western Pacific.The roots of the plant are used to produce a drink with sedative and anesthetic properties. Kava is consumed throughout the Pacific Ocean cultures of Polynesia, including Hawaii, Vanuatu, Melanesia and some parts of Micronesia. Kava is sedating and is primarily consumed to relax without disrupting mental clarity. Its active ingredients are called kavalactones. A Cochrane Collaboration systematic review of its evidence concluded it was likely to be more effective than placebo at treating short-term social anxiety. Safety concerns have been raised over liver toxicity, largely due to the use of stems and leaves by supplement makers, as opposed to solely the root of the plant as dictated by traditional uses. However, based on a retrospective study of retained P. methysticum drug materials in Germany, the alkaloid pipermethystine, occurring to about 0.2% in the leaves, is an unlikely cause for the observed hepatotoxicity. Whether kava hepatotoxicity may be due to contamination with aflatoxins or other mould hepatotoxins, requires further studies. Heavy use of kava with comorbid alcohol consumption or an existing liver condition appears to lead to malnutrition, weight loss, liver damage (causing elevated serum γ -glutamyl transferase and high-density lipoprotein cholesterol levels), renal dysfunction, rashes, pulmonary hypertension, macrocytosis of red cells, lymphocytopenia, and decreasing platelet volumes.
Medicinal use;
Kava is chewed by some to relieve symptoms of throat pain, as it produces a "numbing" effect on the tongue and throat. The kava is first chewed in the back of the mouth for five to 10 minutes while swallowing the saliva and kavalactones released from the process. It produces an effect similar to that of a chloraseptic spray (An over-the-counter medicine to alleviate sore throat by numbing it, via pump-spraying it into the mouth).
Pharmaceutical and herbal supplement companies extract kavalactones from the kava plant using solvents such as acetone and ethanol to produce pills standardized with between 30% and 90% kavalactones. Some kava herbal supplements have been accused of contributing to very rare but severe hepatotoxic reactions (see section on safety) such may have been due to the use of plant parts other than the root, such as stems or peelings that are known to have been exported to European manufacturers. A kava pill usually has anywhere from 60 mg to 150 mg of kavalactones. By comparison the typical bowl of traditionally prepared kava beverage has around 250 mg of kavalactones.
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