Desmethoxyyangonin is a reversible inhibitor of monoamine oxidase B (MAO-B). Kava is able to increase dopamine levels in the nucleus accumbens and desmethoxyyangonin likely contributes to this effect. This, along with the potential increases of serotonin and other catecholamine concentrations, may be responsible for the purported attention-promoting effects of kava. Desmethoxyyangonin has marked activity on the induction of CYP3A23. The order of potency was desmethoxyyangonin > (+/-)-methysticin > yangonin > (+/-)-dihydromethysticin > (+/-)- dihydrokavain > (+/-)-kavain. The two most potent kava pyrones, desmethoxyyangonin and (+/-)-methysticin displayed a competetive inhibition pattern with mean Ki 0.28 microM and 1.14 microM respectively. The inhibition of MAO-B by kava pyrone-enriched extracts might be an important mechanism for their psychotropic activity.
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