Kavalactone

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The general structure of the kavalactones, without the R1-R2 -O-CH2-O- bridge and with all possible C=C double bonds shown.
The general structure of the kavalactones, without the R1-R2 -O-CH2-O- bridge and with all possible C=C double bonds shown.

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

[edit] 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.)

[edit] 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]

Kavalactones: General structures
Structure 1
Structure 1
Structure 2
Structure 2
Structure 3
Structure 3
Structure 4
Structure 4
Structure 5
Structure 5
Structure 6
Structure 6
Structure 7
Structure 7
Structure 8
Structure 8
Kavalactones
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

[edit] 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]

[edit] 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[7], an alkaloid present in portions of the plant used industrially but normally discarded in traditional preparations (see kava).

[edit] See also

[edit] References

  1. ^ 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. 
  2. ^ Shulgin, A (1973). "The narcotic pepper - the chemistry and pharmacology of Piper methysticum and related species". Bull. Narc. 25 (59): 59-74. 
  3. ^ 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. PMID 15181652. 
  4. ^ Cairney, S et al (2002). "The neurobehavioural effects of kava". Aust N Z J Psychiatry 36 (5): 657-652. doi:10.1046/j.1440-1614.2002.01027.x. PMID 12225450. 
  5. ^ Hunter, A (2006). "Kava (Piper methysticum) back in circulation". Australian Centre for Complementary Medicine 25 (7): 529. 
  6. ^ Cairney, S et al (2003). "Saccade and cognitive function in chronic kava users". Neuropsychopharmacology 28 (2): 389-396. doi:10.1038/sj.npp.1300052. PMID 12589393. 
  7. ^ 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:10.1093/toxsci/kfh067. PMID 14737001. 

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