Kavalactones are a class of lactone compounds found in kava roots and Alpinia zerumbet (Shell ginger).[1] Kavalactones are under research for potential to have various psychotropic effects, including anxiolytic and sedative/hypnotic activities.
Kava extract has been shown in vitro to potentially inhibit a wide range of hepatic enzymes, suggesting a possible potential for interactions with many pharmaceuticals and herbal medications.[2] In human volunteers in vivo inhibition is currently limited to CYP1A2,[3] and CYP2E1[4] through use of probe drugs to measure inhibition.
Several preliminary studies are assessing potential effects of kava, including its anxiolytic actions[5] and hepatotoxicity, but the role specifically of kavalactones among many other kava compounds for these effects remains under study.[6][7]
Kavalactone type compounds may help protect against high glucose induced cell damage.[8]
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,[6][9] particularly from extracts, as opposed to whole root powders.
See also: Flavokavain |
At least 18 different kavalactones have been identified to date, with methysticin being the first identified.[10] Multiple analogues, such as ethysticin, have also been isolated.[11] 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.[12]
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 |
Desmethoxyyangonin | 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 | -O-CH2-O- | -H | -H | |
Methysticin | 7 | -O-CH2-O- | -H | -H | |
7,8-dihydromethysticin | 8 | -O-CH2-O- | -H | -H |
The kavalactone biosynthetic pathway in Piper methysticum was described in 2019.[13]