Kava

Kava or kava-kava (Piper methysticum) (PiperLatin for ‘pepper’, methysticum: (Latinized) Greek for ‘intoxicating’) is a crop of the western Pacific.

The name kava(-kava) is from Tongan and Marquesan;[1] other names for kava include ʻawa (Hawaiʻi), ava (Samoa), yaqona (Fiji), and sakau (Pohnpei).

The roots of the plant are used to produce a drink with sedative and anesthetic properties. Kava is consumed throughout the Pacific Ocean cultures ofPolynesia (including Hawaii), VanuatuMelanesia 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 that it was likely to be more effective than placebo at treating short-term social anxiety.[2] 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.[3][4] However, based on a retrospective study of retained Piper methysticum drug materials in Germany, the alkaloid pipermethystine, occurring to about 0.2% in the leaves, is an unlikely cause for the observed hepatotoxicity.[5] Whether kava hepatotoxicity may be due to contamination with aflatoxicosis or other mould hepatotoxins, requires further studies.[6] 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 dysfunctionrashespulmonary hypertension,macrocytosis of red cellslymphocytopenia, and decreasing platelet volumes.[7]

Herbal medicine

Kava is chewed by some to relieve symptoms of throat pain, as Kava produces a “numbing” effect on the tongue and throat. The Kava is first chewed in the back of the mouth for 5 to 10 minutes while swallowing the saliva and kavalactones released from the process. The Kava produces an effect similar to that of a chloraseptic spray (An over-the-counter medicine to alleviate sore throat by numbing it, via pump-sprayed into the mouth).

Pharmacology

Kava’s active principal ingredients are the kavalactones, of which at least 15 have been identified and are all considered psychoactive. Only six of them produce noticeable effects, and their concentrations in kava plants vary. Different ratios can produce different effects.

Pharmacodynamics

Effects of kavalactones include mild sedation, a slight numbing of the gums and mouth, and vivid dreams. Kava has been reported to improve cognitive performance and promote a cheerful mood.[15] Kava has similar effects to benzodiazepine medications, including muscle relaxant,anaestheticanticonvulsive and anxiolytic effects. They are thought to result from direct interactions of kavalactones with voltage-gated ion channels.[16] Research currently suggests that kavalactones potentiate GABAA activity but do not alter levels of dopamine and serotonin in theCNS.[17]Heavy, long-term kava use does not cause any reduction of ability in saccade and cognitive tests but is associated with elevated liver enzymes.[18]

Desmethoxyyangonin, one of the six major kavalactones, is a reversible MAO-B inhibitor (Ki 280 nM)[19] and is able to increase dopamine levels in the nucleus accumbens. This finding might correspond to the slightly euphoric action of kava.[20]

Kavain, in both enantiomeric forms, inhibits the reuptake of noradrenalin at the transporter (NAT), but not of serotonin (SERT).[21] An elevatedextracellular noradrenalin level in the brain may account for the reported enhancement of attention and focus.

{Information courtesy Wikipedia}