Kavalactones are a class of lactone compounds found in the kava shrub. Kavalactones have a wide variety of effects including amnestic, analgesic, anticonvulsant, anxiolytic, nootropic, and sedative/hypnotic activity caused by numerous interactions with the central nervous system via several mechanisms.
Kava extract has been shown to potently inhibit a wide range of hepatic enzymes, suggesting a very high potential for interactions with many pharmaceuticals and herbal medications. For this reason, kava should never be consumed without the permission of a primary care physician, psychiatrist, and/or any other doctor who is prescribing medication for a patient. It is also recommended that potential users discuss their kava use with a pharmacist. If undergoing anesthesia, it is recommended to note any use of kava well in advance of any surgery. Patients may be instructed to temporarily discontinue use of kava for a set period of time before and after the surgery.
Several kavalactones (e.g.Methysticin and Yangonin) have been reported to induce activity of CYP1A1. Hepatoxicity has been reported in a small portion of previously healthy kava users, particularly of extracts as opposed to whole root powders.
Numerous kavalactones have apoptotic effects on various human tissues, which may be involved in some of the purported toxic effects of kava use.
At least 18 different kavalactones have been identified to date, with methysticin being the first identified. Multiple analogues, such as ethysticin, have also been isolated. Some consist of a substituted α-pyrone as the lactone while others are partially saturated.
The average elimination half-life of kavalactones typically present in kava root is 9 hr.
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