Accumulation of Anthoxanthins and Iminoacids in Leaf Galls of Salix fragilis L.

Abstract

GALL formation in the Salicaceae is common, and sawflies are frequently responsible. Investigation of the chemical changes initiated by the insects was made on the leaf galls of Salix fragilis L. produced by the sawfly Pontania proxima Lep. In preliminary studies, Challen¹ suggested that one phytochemical change initiated by P. proxima might be an accumulation of catechins, leucoanthocyanidins and a ninhydrin positive substance. A red pigment, cyanidin-3-monoglucoside, was found in young leaves and galls by Blunden and Challen². In the present investigation a concentrated methanolic extract of fresh galls was purified by band chromatography on Whatman No. 3MM paper, using distilled water as the solvent. The leucoanthocyanidin and cateohin band, detected by spraying a marker strip of the chromatogram with vanillin (equal volumes of hydrochloric acid B.P., and a mixture of vanillin 2 per cent w/v + acetaldehyde 1 per cent v/v in 95 per cent ethanol), was cut out and eluted with 2 N hydrochloric acid. The leucoanthocyanidins were converted to their anthocyanidins by the method of Bate-Smith³ and purified by band chromatography. The eluted pigment was subjected to paper chromatography using methods recommended by Harborne⁴. The anthocyanidin had similar R_F values to a reference sample of cyanidin chloride in all three solvent systems used.