This MedLibrary.org supplementary page on Kavalactone is provided directly from the open source Wikipedia as a service to our readers. Please see the note below on authorship of this content, as well as the Wikipedia usage guidelines. To search for other content from our encyclopedia supplement, please use the form below:
Related Sponsors
Kavalactones are the main psychoactive components of the roots of Piper methysticum (kava), a shrub common on some Pacific Ocean islands. Another class of compounds found in P. methysticum are the Flavokawains, which are substituted chalcones in nature and not lactones, and thus they are not kavalactones.
Contents |
Extraction
The rhizome and roots of the shrub are ground, grated and steeped in water to produce a non-alcoholic drink which is said to promote sociability, mental clarity, and reduction of anxiety (see main kava entry). The quantity and ratio of kavalactones present vary dramatically and are highest when roots are extracted with solvents rather than by conventional tea preparation (but note safety issues; see kava).[1]
Some use lipids to aid in kavalactone extraction. (ie; whole milk, oils, etc.)
Compounds
At least 18 different kavalactones have been identified to date, with Methysticin being the first identified. The Flavokawains are not kavalactones and as such are not included in the table below, which only lists natural kavalactones that have been identified in P. methysticum (and thus does not include pharmacologically interesting synthetic analogues, such as ethysticin).[2]
|
|
|
|
|
|
|
|
| Name | Structure | R1 | R2 | R3 | R4 |
|---|---|---|---|---|---|
| Yangonin | 1 | -OCH3 | -H | -H | -H |
| 10-methoxyyangonin | 1 | -OCH3 | -H | -OCH3 | -H |
| 11-methoxyyangonin | 1 | -OCH3 | -OCH3 | -H | -H |
| 11-hydroxyyangonin | 1 | -OCH3 | -OH | -H | -H |
| 5,6-dehydrokavain | 1 | -H | -H | -H | -H |
| 11-methoxy-12-hydroxydehydrokavain | 1 | -OH | -OCH3 | -H | -H |
| 7,8-dihydroyangonin | 2 | -OCH3 | -H | -H | -H |
| Kavain | 3 | -H | -H | -H | -H |
| 5-hydroxykavain | 3 | -H | -H | -H | -OH |
| 5,6-dihydroyangonin | 3 | -OCH3 | -H | -H | -H |
| 7,8-dihydrokavain | 4 | -H | -H | -H | -H |
| 5,6,7,8-tetrahydroyangonin | 4 | -OCH3 | -H | -H | -H |
| 5,6-dehydromethysticin | 5 | - | - | -H | -H |
| Methysticin | 7 | - | - | -H | -H |
| 7,8-dihydromethysticin | 8 | - | - | -H | -H |
Effects
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. [3] Muscle relaxant, anaesthetic, anticonvulsive and anxiolytic effects are thought to result from direct interactions of kavalactones with voltage-gated ion channels. [4] Research currently suggests that kavalactones potentiate GABAA activity but do not alter levels of dopamine and serotonin in the CNS. [5] Heavy, long-term kava use does not cause any reduction of ability in saccade and cognitive tests but is associated with elevated liver enzymes. [6]
Desmethoxyyangonin, one of the six major kavalactones, is a reversible MAO-B inhibitor (Ki 280 nM)[7] and is able to increase dopamine levels in the nucleus accumbens. This finding might correspond to the slightly euphoric action of kava.[8]
Kavain in both enantiomeric forms inhibit the reuptake of noradrenalin at the transporter (NAT), but not of serotonin (SERT).[9] An elevated extracellular NA level in the brain may account for the reported enhancement of attention and focus with kava.
Adverse effects
The United States Food and Drug Administration (FDA) has warned that very rare cases of liver damage or fulminant liver failure may be caused by kava-containing supplements. However, these injuries might result from pipermethystine[10], an alkaloid present in portions of the plant used industrially but normally discarded in traditional preparations (see kava).
See also
References
- ^ Hu, A et al (2005). "Determination of six kavalactones in dietary supplements and selected functional foods containing Piper methysticum by isocratic liquid chromatography with internal standard". J AOAC Int. 88 (1): 16–25. PMID 15759721.
- ^ Shulgin, A (1973). "The narcotic pepper - the chemistry and pharmacology of Piper methysticum and related species". Bull. Narc. 25 (59): 59–74.
- ^ Thompson, R et al (2004). "Enhanced cognitive performance and cheerful mood by standardized extracts of Piper methysticum (Kava-kava)". Hum Psychopharmacol. 19 (4): 243–250. doi:. PMID 15181652.
- ^ Cairney, S et al (2002). "The neurobehavioural effects of kava". Aust N Z J Psychiatry 36 (5): 657–652. doi:. PMID 12225450.
- ^ Hunter, A (2006). "Kava (Piper methysticum) back in circulation". Australian Centre for Complementary Medicine 25 (7): 529.
- ^ Cairney, S et al (2003). "Saccade and cognitive function in chronic kava users". Neuropsychopharmacology 28 (2): 389–396. doi:. PMID 12589393.
- ^ Uebelhack R, Franke L, Schewe HJ (1998): “Inhibition of platelet MAO-B by kava pyrone-enriched extract from kava-kava.” Pharmacopsychiatry 31(5):187-92. PMID 9832350
- ^ Baum SS, Hill R, Rommelspacher H (1998): “Effect of kava extract and individual kavapyrones on neurotransmitter levels in the nucleus accumbens of rats.” Prog Neuropsychopharmacol Biol Psychiatry 22(7):1105-20. PMID 9829291
- ^ Seitz U, Schule A, Gleitz J (1997): "[3H]-monoamine uptake inhibition properties of kava pyrones." Planta Med. 63(6):548-9. PMID 9434608
- ^ Nerurkar, PV et al (2004). "In vitro toxicity of kava alkaloid, pipermethystine, in HepG2 cells compared to kavalactones". Toxicological Sciences 79 (1): 106–111. doi:. PMID 14737001.
External links
 |
This pharmacology-related article is a stub. You can help Wikipedia by expanding it. |
Wikipedia content modification information:
- This page was last modified on 29 September 2008, at 04:15.
Wikipedia Authorship and Review
Wikipedia content provided here is not reviewed directly by MedLibrary.org. Wikipedia content is authored by an open community of volunteers and is not produced by or in any way affiliated with MedLibrary.org.
Wikipedia Usage Guidelines
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article on "Kavalactone".
The URL for this specific entry is:
All Wikipedia text is available under the terms of the GNU Free Documentation License. (See Copyrights for details). Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc.