The effect of the sample preparation method of extractable phenolics of Salicaceae species

The effect of different tissue prehandling methods on the phenolic content of willow bark, leaves, and twigs was studied. The phenolics were extracted at room temperature, purified, and analyzed by high resolution capillary gas chromatography. Neither oven-drying at a low temperature nor room-drying of fresh leaves and oven-drying of bark produced any qualitative changes in the glucoside composition and only a minor binding effect was seen on the amounts of each glucoside. On the other hand, oven-drying of the intact long twigs and room-drying of the bark are prehandling methods to avoid. Freeze-drying or immediate analysis of frozen leaves lowered the total amount of glucosides and caused considerable qualitative changes to the glucoside composition. 80% acetone was found to be slightly more effective and gentle extraction solvent for all glucosides compared with methanol.