Identification of a spirostane-type saponin in the flowers of leek with inhibitory effects on growth of leek-moth larvae

Abstract

The toxic compound for leek-moth larvae, Acrolepiopsis assectella has been isolated from the flowers of leek, Allium porrum and identified as 3-O-[[β- d- xylopymnosyl (1→3)]-[β- d-glucopyranosyl (1→2)]-[β- d-glucopyranosyl (1→4)]-[β- dgalactopyranosyl]-(25 R)-5α-spirostan-2α,3β,6β-triol. The compound is identical with aginosid, a saponin isolated earlier from , Allium giganteum. The toxicity of the compound is reduced by the addition of cholesterol or sitosterol to the diet. The differences in toxicity between leek flowers and leaves are discussed.