pipermethystine pipermethystine pipermethystine is a toxic alkaloid present in the aerial (aboveground) portions of the kava plant. it is not a kavalactone, containing no lactone structure. correctly prepared kava root products will contain almost no pipermethystine. pipermethystine names iupac name acetate identifiers cas number 71627-22-0 y375797-98-1 y 3d model (jsmol) interactive image chemspider 9406563 pubchem cid 11231515 unii apx8c8s6aw y comptox dashboard (epa) dtxsid60992199 inchi inchi=1s/c16h17no4/c1-12(18)21-14-8-10-16(20)17(11-14)15(19)9-7-13-5-3-2-4-6-13/h2-6,8,10,14h,7,9,11h2,1h3/t14-/m0/s1key: jlnnqcuatonmit-aweznqclsa-ninchi=1/c16h17no4/c1-12(18)21-14-8-10-16(20)17(11-14)15(19)9-7-13-5-3-2-4-6-13/h2-6,8,10,14h,7,9,11h2,1h3/t14-/m0/s1key: jlnnqcuatonmit-aweznqclbw smiles o=c(n1c(=o)\c=c/(oc(=o)c)c1)ccc2ccccc2 properties chemical formula c16h17no4 molar mass 287.31 g/mol except where otherwise noted, data are given for materials in their standard state (at 25 °c , 100 kpa). infobox references toxicity several studies suggest pipermethystine induces hepatotoxicity in humans, and was first believed to be the cause of liver failure in individuals consuming kava supplements, but not in proper root powder or fresh root, which is consumed in the traditional kava cultures of polynesia. later analyses of the implicated drug materials and products revealed that medical kava extracts contain less than 45 ppm of this alkaloid, while the leaves contain about 0.2% (2000ppm). based on this retrospective study, pipermethystine is an unlikely cause for the observed hepatotoxicity of commercial kava preparations.