New valorization strategies for Eucalyptus spp. bark extracts

The forest-based industry is important industrial sector in Europe, and particularly in Portugal. The increasingly higher demands for competitiveness, in forest-industry prompted the exploitation of different side-streams, such as bark residues. Within a biorefinery-based con-cept, these residues can be further refined to high value-added chemicals, with relevance for chemical and pharmaceutical industries. Results from our research team reveal that Eucalyptus globulus bark lipophilic extracts contain high quantities of triterpenoids (up to 12g/kg bark), pre-dominantly triterpenic acids (TAs), namely betulinic, betulonic, ursolic and oleanolic acids. Sim-ilar composition has also been detected on Eucalyptus nitens outer bark. In the present work we report the chemical characterization of Eucalyptus spp. bark derived extracts, rich in TAs and the assessment of their antitumoral potential, using two distinct in vitro human cancer cell models. Our results represent an important step forward in terms of economic valorization of Eucalyptus spp bark residues derived from forest industry.