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 a class of lactone compounds found in the kava shrub. Kavalactones are under research for potential to have various psychotropic effects, including anxiolytic and sedative/hypnotic activities.
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.[1]
Research[]
Several preliminary studies are assessing potential effects of kava, including its anxiolytic actions[2] and hepatotoxicity, but the role specifically of kavalactones among many other kava compounds for these effects remains under study.[3][4]
Toxicity[]
Several kavalactones (e.g. methysticin and yangonin) affect a group of enzymes involved in metabolism, called CYP1A1. Hepatotoxicity occurred in a small portion of previously healthy kava users,[3][5] particularly from extracts, as opposed to whole root powders.
At least 18 different kavalactones have been identified to date, with methysticin being the first identified.[6]
Multiple analogues, such as , have also been isolated.[7]
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.[8]
Name
Structure
R1
R2
R3
R4
Yangonin
1
-OCH3
-H
-H
-H
1
-OCH3
-H
-OCH3
-H
1
-OCH3
-OCH3
-H
-H
1
-OCH3
-OH
-H
-H
Desmethoxyyangonin
1
-H
-H
-H
-H
1
-OH
-OCH3
-H
-H
2
-OCH3
-H
-H
-H
Kavain
3
-H
-H
-H
-H
3
-H
-H
-H
-OH
3
-OCH3
-H
-H
-H
7,8-dihydrokavain
4
-H
-H
-H
-H
4
-OCH3
-H
-H
-H
5
-O-CH2-O-
-H
-H
Methysticin
7
-O-CH2-O-
-H
-H
7,8-dihydromethysticin
8
-O-CH2-O-
-H
-H
Kavalactones: General structures
Structure 1
Structure 2
Structure 3
Structure 4
Structure 5
Structure 6
Structure 7
Structure 8
Biosynthesis[]
The kavalactone biosynthetic pathway in Piper methysticum was described in 2019.[9]
^Sarris, Jerome; LaPorte, Emma; Schweitzer, Isaac (2011-01-01). "Kava: A Comprehensive Review of Efficacy, Safety, and Psychopharmacology". Australian & New Zealand Journal of Psychiatry. 45 (1): 27–35. doi:10.3109/00048674.2010.522554. PMID21073405. S2CID42935399.
^ abTeschke, R; Lebot, V (2011). "Proposal for a kava quality standardization code". Food and Chemical Toxicology. 49 (10): 2503–16. doi:10.1016/j.fct.2011.06.075. PMID21756963.
^Teschke, R; Qiu, S. X.; Xuan, T. D.; Lebot, V (2011). "Kava and kava hepatotoxicity: Requirements for novel experimental, ethnobotanical and clinical studies based on a review of the evidence". Phytotherapy Research. 25 (9): 1263–74. doi:10.1002/ptr.3464. PMID21442674. S2CID19142750.