Methysticin is one of the six major kavalactones found in the kava plant. Research suggests that methysticin and the related compound dihydromethysticin have CYP1A1 inducing effects which may be responsible for their toxicity. Methysticin induces the function of the hepatic enzyme CYP1A1, an enzyme involved in the toxification of benzo[a]pyrene into benzopyrene-7,8-dihydrodiol-9,10-epoxide, one of the most highly carcinogenic substances known. This property is shared by the related compound dihdromethysticin, both of which occur in significant quantities in Piper methysticum. Glutathione oxidation was measured using the ortho-phthalaldehyde (OPT) fluorescence assay. Kavain had minimal cytotoxicity, methysticin showed moderate concentration-dependent toxicity and yangonin displayed marked toxicity with ~ 40% reduction in viability in EB assay.
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