Targeted Salix Crossing and Chemoprofiling for Improved Medicinal Potential of Willow Bark

Deforestation of Salix species for fuel as renewable sources for energetic use had priority in the past. However, the mobilization of dendromass from forests is limited and therefore, short-rotation plantations (SRP) with fast-growing tree species such a Salix become more important. Usually whole Salix shoots are used for bioenergy purposes, which results in an unclean combustion due to the bark. To cope up with these disadvantages, the efficiency and attractiveness of SRP as sustainable form of land use has to be enhanced. Accordingly, object of the proposed study is to investigate the chemical composition of the so far rarely used willow bark for possible use as phytopharmaceutical as additional usage of SRP (heartwood) for bioenergy. With increasing life expectancy and growth of elderly population, an alarming escalation of age-related chronic, inflammatory disease conditions are noted demanding new treatments and preventive approaches. The therapeutic and health-promoting effects of willow bark preparations, especially against inflammatory diseases and pain conditions in humans, are known, however the correlation of therapeutic effects to certain individual bioactive compounds (i.e. secondary plant metabolites) or combinations is still lacking consequently impairing product optimization. To date, willow bark extracts were only evaluated according to their salicin content. Other secondary metabolites in the bark were not taken into consideration. Furthermore, breeding programs focused solely on biomass production. Therefore, in the proposed study the natural genetic biodiversity in the gene pool of willow crop species and targeted crosses is used to generate different chemotypes, which are tested for their bioactivity, i. e. therapeutic potential. To generate distinct chemoprofiles, Salix species crosses are screened (Salix daphnoides, Salix purpurea, and Salix viminalis) and new crossing of species will be performed (Salix alba, Salix fragilis, Salix hastata, Salix myrsinifolia, Salix pentandra, Salix repens, and Salix triandra). Objective of the proposed project is to identify suitable willow clones which exhibit high secondary metabolite levels with best medicinal effects to use as phytopharmaceutical and which also show a high biomass production and rust resistance. Extracts from these Willow barks should achieve specific therapeutic benefits with few undesirable side effects and should be suitable to extend standard medications such as Aspirin™ in the treatment of inflammation related diseases. Finally, these crosses will be made available to the public.