Effect of storage and drying on the content of salicylates and flavonoids in willow bark (Salix purpurea)

Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used against mild pain and inflammatory conditions. However, the NSAIDs have several adverse effects, such as bleeding or perforation in the gastrointestinal tract. These adverse effects have been estimated to account for at least 7,600 deaths in the United States alone. Therefore it is important to find effective
alternatives to NSAIDs.
Traditional medicine based on willow bark could be a possible alternative to NSAIDs drugs as willow bark has demonstrated pain-relieving and anti-inflammatory activity. This effect hasmainly been associated with its high concentrations of salicin and salicin derivatives that are prodrugs for salicylic acid, which is also the active compound in one of the most widely used NSAIDs,
Aspirin. However, the anti-inflammatory effect of willow bark cannot be ascribed solely to its content of salicin equivalents, and hence their conversion to salicylic acid. This clearly indicates that additional anti-inflammatory activity of the bark is either caused by synergistic effects or may be due to salicin derivatives or other constituents, such as flavonoids [3]. As willow bark is often stored before processing it is important to know the effect of different storage and drying methods on the stability of salicin and other components in the bark.
In the present study the influence of storage and drying of willow bark was investigated by comparing the concentrations of known compounds in unprocessed fresh bark with the concentrations in the stored and dried bark samples.