abstract
Ultra-high performance liquid chromatography (UHPLC) was applied for the first time in the analysis of wood extracts. The potential of this technique coupled to ion trap mass spectrometry in the rapid and effective detection and identification of bioactive components in complex vegetal samples was demonstrated. Several dozens of compounds were detected in less than 30 min of analysis time, corresponding to more than 3-fold reduction in time, when compared to conventional HPLC analysis of similar extracts. The phenolic chemical composition of Eucalyptus grandis, Eucalyptus urograndis (E. grandis x E. urophylla) and Eucalyptus maidenii wood extracts was assessed for the first time, with the identification of 51 phenolic compounds in the three wood extracts. Twenty of these compounds are reported for the first time as Eucalyptus genus components. Ellagic acid and ellagic acid-pentoside are the major components in all extracts, followed by gallic and quinic acids in E. grandis and E. urograndis and ellagic acid-pentoside isomer, isorhamnetin-hexoside and gallic acid in E. maidenii. The antioxidant scavenging activity of the extracts was evaluated, with E. grandis wood extract showing the lowest IC50 value. Moreover, the antioxidant activity of these extracts was higher than that of the commercial antioxidant BHT and of those of the corresponding bark extracts. These results, together with the phenolic content values, open good perspectives for the exploitation of these renewable resources as a source of valuable phenolic compounds. (c) 2013 Elsevier B.V. All rights reserved.
keywords
MOLECULAR-WEIGHT POLYPHENOLS; DIODE-ARRAY DETECTION; HYDROLYZABLE TANNINS; ANTIOXIDANT ACTIVITY; BARK EXTRACTS; OUTER BARKS; E-RUDIS; GLOBULUS; MSN; CAMALDULENSIS
subject category
Biochemistry & Molecular Biology; Chemistry
authors
Santos, SAO; Vilela, C; Freire, CSR; Neto, CP; Silvestre, AJD
our authors
Armando Jorge Domingues Silvestre
Full professor
Carla Vilela
Assistant Professor
Carlos Pascoal Neto
Raiz Director
Carmen Sofia da Rocha Freire Barros
Coordinating Researcher
Sónia Andreia Oliveira Santos
Assistant Researcheracknowledgements
The authors wish to thank RAIZ - Instituto de Investigacao da Floresta e Papel for kindly providing the Eucalyptus wood samples. The authors also wish to thank FCT (Fundacao para a Ciencia e Tecnologia) and POPH/FSE for the postdoctoral grants to S.A.O. Santos (SFRH/BPD/84226/2012) and C. Vilela (SFRH/BPD/84168/2012) and for funding CICECO (Pest-C/CTM/LA0011/2013).