NEW PISCICIDAL TRITERPENES FROM IRIS GERMANICA

Abstract

Three new piscicidal triterpenens named irisgermanicals A, B and C along with seven known iridal-type triterpenes including iripallidal and iriflorental were isolated from the bark of Iris germanica rhizome, upon bioassay-guided fractionation using the Medaka (killie-fish; Oryzias latipes), and their bicyclic structures were elucidated based on the spectral analyses. Irisgermanicals B and C were characterized as geometrical iriflorental and iripallidal isomers, respectively, concerning the α, β-unsaturated aldehyde moiety. The piscicidal activity was observed for bicyclic iridals, among which iriflorental exhibited most potent activity.