Exploiting the Integrated Valorization of Eucalyptus globulus Leaves: Chemical Composition and Biological Potential of the Lipophilic Fraction before and after Hydrodistillation

abstract

E. globulus leaves have been mainly exploited for essential oil recovery or for energy generation in industrial pulp mills, neglecting the abundance of valuable families of extractives, namely, triterpenic acids, that might open new ways for the integrated valorization of this biomass. Therefore, this study highlights the lipophilic characterization of E. globulus leaves before and after hydrodistillation, aiming at the integrated valorization of both essential oils and triterpenic acids. The lipophilic composition of E. globulus leaves after hydrodistillation is reported for the first time. Extracts were obtained by dichloromethane Soxhlet extraction and analyzed by gas chromatography-mass spectrometry. In addition, their cytotoxicity on different cell lines representative of the innate immune system, skin, liver, and intestine were evaluated. Triterpenic acids, such as betulonic, oleanolic, betulinic and ursolic acids, were found to be the main components of these lipophilic extracts, ranging from 30.63-37.14 g kg(-1) of dry weight (dw), and representing 87.7-89.0% w/w of the total content of the identified compounds. In particular, ursolic acid was the major constituent of all extracts, representing 46.8-50.7% w/w of the total content of the identified compounds. Other constituents, such as fatty acids, long-chain aliphatic alcohols and b-sitosterol were also found in smaller amounts in the studied extracts. This study also demonstrates that the hydrodistillation process does not affect the recovery of compounds of greatest interest, namely, triterpenic acids. Therefore, the results establish that this biomass residue can be considered as a promising source of value-added bioactive compounds, opening new strategies for upgrading pulp industry residues within an integrated biorefinery context.

keywords

URSOLIC ACID; ANTIOXIDANT ACTIVITIES; BETULINIC ACID; RICH SOURCE; IN-VITRO; BARK; EXTRACTS; IDENTIFICATION; DERIVATIVES; LABILL.

subject category

Biochemistry & Molecular Biology; Chemistry

authors

Oliveira, CSD; Moreira, P; Cruz, MT; Pereira, CMF; Silva, AMS; Santos, SAO; Silvestre, AJD

Groups

G4 - Renewable Materials and Circular Economy

Projects

InPaCTus - Innovative Products and Technologies from Eucalyptus Project (InPacTus)

CICECO - Aveiro Institute of Materials (UIDB/50011/2020)

CICECO - Aveiro Institute of Materials (UIDP/50011/2020)

Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)

acknowledgements

This work was carried out under the Project InPacTus-Innovative products and technologies from eucalyptus, Project N.o 21874 (POCI-01-0247-FEDER-021874), funded by Portugal 2020 through the European Regional Development Fund (ERDF) in the frame of COMPETE 2020 no 246/AXIS II/2017, and the projects CICECO-Aveiro Institute of Materials (UIDB/50011/2020, UIDP/50011/2020 and LA/P/0006/2020), LAQV-REQUIMTE (UIDB/50006/2020 and UIDP/50006/2020) and CIBB (UIDB/04539/2020 and UIDP/04539/2020), financed by national funds through the FCT/MEC (PIDDAC). FCT is also acknowledged for the research contract under the Scientific Employment Stimulus to S. Santos (2021.03348.CEECIND).