Extraction of isoflavonoids from Iresine herbstii

Biliary atresia outbreaks were reported four times in newborn Australian livestock between 1964 and 2013. Epidemiologic data implied that these outbreaks were caused by environmental exposure to an unusual forage plant. We isolated and identified the active toxic compound. Two similar isoflavonoids from Iresine herbstii have been reported. We have extracted I. herbstii, and are isolating the compounds by column chromatography, flash chromatography and HPLC. We confirmed the presence of the compounds, 2′,2,5-trimethoxy-6,7-methylenedioxyisoflavanone (1) and 2′,5-dimethoxy-6,7-methylenedioxyisoflavone (2). Future work will focus on ring opening reactions and testing the toxicities of all compounds in a zebrafish bioassay of biliary function. This is part of our ongoing efforts to determine SAR characteristics of the toxic compound.