## 1 Introduction  
_Pinus pinaster_ and _Pinus pinea_ are the two dominant pine species in Portugal, occupying ca. 714,000 and 176,000 ha, which represent 23% and 6% of the total forest area, respectively [1]. These conifers have an important impact on the national economy due to their vast applicability in timber and resin industries and also in pulp fibers production [2]. _P. pinea_ is also cultivated because of the high commercial value of its edible seeds, which have high nutritional value and are a traditional component of the Mediterranean diet [2]. The bark of these two _Pinus_ species consists in an interesting raw material, since it is produced in large amounts (6481 and 253 k ton year\({}^{-1}\) of _P. pinaster_ and _P. pinea_ bark, respectively [3]) as a by-product of the abovementioned industries. These bark residues are simply burnt to produce energy or used as an organic substrate for plant nurseries after composting. An interesting alternative is their exploitation as a source of added-value chemicals, such as bioactive ingredients with potential nutraceutical applications, which ultimately can be integrated into the referred traditional applications in a biorefinery perspective [4] in order to maximize the biomass value. Resin acids (mainly abietane-type resin acids, including the abietic, neoabietic, palustric, and levopimaric acids, and minor amounts of pimarane-type resin acids, including the pimaric, isopimaric, and sandaracopimaric acids) are the major components of _Pinus_ spp. wood resin [5]. Small amounts of dehydroabietic acid (DHAA), obtained by dehydrogenation of abietane-type resin acids, can also be found in wood resins. These compounds have been exploited as important commodities for the chemical industry [5]. In addition, they play an important role in the chemical defense of conifers. Many examples show a relationship between conifer diterpene acid content and a tree's resistance to potential herbivores and pathogens [6]. Furthermore, resin acids display important beneficial properties for human health, being the antimicrobial, antiulcer, and cardiovascular activities the most representative ones [7, 8]. Due to the mentioned significant biological properties, the search for new natural and synthetic resin acid derivatives has been an active research field. Most of these compounds have been tested for their cytotoxicity against cancer cells [9, 10, 11, 12, 13, 14], and their antioxidant [9, 15], antiviral [10, 11, 16], antimycotic [10], and gastroenter [12] activities. Resin acids can also be found in the lipophilic extracts of different morphological parts of several _Pinus_ spp. [17, 18, 19, 20, 21, 22, 23, 24, 25], including the bark of _Pinus nigra_[21], the Turkish _P. pinea_ L. [23], and the Pakistani _Pinus wallichiana_, _Pinus roxburghii_, and _Pinus gerardiana_[25]. Among the resin acids that have been identified in bark lipophilic extracts are the pimaric, sandaracopimaric, levopimaric, palustric, isopimaric, abiotic, dehydroabietic, and neoabietic acids, and the 7-oxodehydroabietic, 16-hydroxydehydroabietic, and 8,15-isopimaridien-18-oic acids [21, 23, 25]. Additionally, other lipophilic constituents of _Pinus_ spp. bark, such as several fatty acids, aliphatic alcohols, sterols (mainly \(\beta\)-sitosterol), \(\beta\)-caryophyllene, and some aromatic compounds (ferulic acid, vanillin, etc. ), have also been detected [21, 23, 25]. Although there are some compositional studies of bark from _P. pinaster_[26, 27] and _P. pinea_[28] cultivated in Portugal, a detailed chemical characterization of their lipophilic components is still missing. Therefore, in the present work, dichloromethane (DCM) extracts of bark from the referred _Pinus_ spp. collected from the Centre of Portugal were prepared and analyzed by gas chromatography-mass spectrometry (GC-MS). The main aim was to evaluate the exploitation potential of these industries' by-products as an alternative source of bioactive compounds (e.g., resin acids) for further applications, such as nutraceutical and cosmetic usages.