Pinus pinaster Aiton. Pinus pinea L. SUSFOR FCT Doctoral Program Phytochemical composition of young phloem from Pinus pinaster Aiton and Pinus pinea L. Rita Simões a*, Carla Pimentel a, Isabel Miranda a and Helena Pereira a INTRODUCTION The forest in Portugal occupies about 35% of the national territory, of which 23% corresponds to pine trees with great socio-economic impact. Maritime pine (Pinus pinaster Aiton) and stone pine, or Portuguese pine (Pinus pinea L.), are the two dominant species of the genus pinus in Portugal. However, the occurrence of some pest and diseases is a matter of concern, namely the nematode that attacks mostly P. pinaster. Earlier studies suggested that the chemical composition of the species may have some role in its susceptibility (Pimentel et al., 2016). This study aims to evaluate the production of secondary metabolites and gain knowledge about the phytochemical composition of young phloem from maritime pine and portuguese pine including its seasonal variation. MATERIALS AND METHODS The samples were removed, to be chemically analyzed, from the young branches with a 5- 6 year-old phloem (formed in 2011 and 2012) of a total of 24 trees: RESULTS AND DISCUSSION The extractive content in ethanol is higher for the young phloem from P. pinea. The total extractive content is similar for both species. (Figure 1) The total phenolic content varies significantly between species. The concentration of hydrolysable tannins of the Portuguese pine is about twice that found for maritime pine. (Table 1) The two principal components explain 58.4% of the phytochemical composition variability of the young phloem of the two species as it can be seen in the Principal Components Plot K-means clusters. (Figure 2) Pinus pinaster Aiton. 6 trees from Herdade da Apostiça 6 trees from Melides Pinus pinea L. Figure 1 – Box-plots representing the extractive content on Pinus pinaster Aiton (left) and Pinus pinea L. (right). CH2Cl2(%) C2H5OH(%) H2O(%) Total(%) The samples were lyophilized and milled with a coffee mill The samples were extracted successively with dichloromethane, ethanol and water in individual Ankon filter bags using the Soxhlet method. (Alves et al., 2012) The content in phenolics, flavonoids and tannins were determined from the ethanol/water extract. (Miranda et al., 2016) Table 1 – Polar compounds from the etanol/water extract of young phloem. CONCLUSION The phloems of P. pinaster and P. pinea are chemically distinguishable, mainly by the total phenolic content, flavonoids and hydrolysable tannin. The identification of homogeneous groups was possible due to the cluster analysis, based on the studied variables. Figure 2 – Principal Components Plot K-means clusters. REFERENCES A. Alves, R.F.S. Simoes, C.Santos, B. Potts, J.C. Rodrigues, M. Schwanninger. Determination of Eucalyptus globulus wood extractives content by NIR-based PLS-R models: Comparison between extraction procedures. J. Near In frared Spectroscopy 20(2), Pages: 275-285 [2012] doi: 10.1255/jnirs.987 C. S. Pimentel, P. N. Firmino, T. Calvão, M. P. Ayres, I. Miranda and H. Pereira. Pinewood nematode population growth in relation to pine phloem chemical composition. Plant Pathology [2016]. Miranda I., Lima L., Quilhó T., Knapic S., Pereira H. The bark of Eucalyptus sideroxylon as a source of phenolic extracts with anti-oxidant properties. Industrial Crops and Products 82:81.87. [2016] doi:10.1016/j.indcrop.2015.12.003 ACKNOWLEDGEMENTS This research was carried out under the framework of Centro de Estudos Florestais, a research unit funded by Fundação para a Ciência e a Tecnologia, Portugal. The 1st Author acknowledges a FCT doctoral fellowship (PD/BD/128259/2016) under the Sustainable Forest and Products (SUSFOR) doctoral program. Contact information: a: Centro de Estudos Florestais, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017 Lisboa, Portugal *Corresponding author: ritafabiana@isa.ulisboa.pt CIÊNCIA 2017_ Encontro com a Ciência e Tecnologia em Portugal, CONGRESS CENTRE-LISBON, PORTUGAL, 3-5 JULY 2017