Chemical composition variation of essential oils of Copaifera langsdorffii Desf. from different vegetational formations

Abstract This study aims to provide information about the chemical profile of the essential oil from C. langsdorffii resin in areas of Cerradão, Carrasco, and Humid Forest. In order to obtain the essential oils, oil-resin was submitted to hydrodistillation process, and the chemical components were analyzed by gas chromatography coupled to mass spectrometry (GC/MS). Twenty-six constituents were identified in the essential oil of C. langsdorffii resin, of which 12 were present in Cerradão, 15 in Carrasco and 18 in Humid Forest, with β-bisabolene, caryophyllene oxide, γ-muurolene, α-caryophyllene and β-caryophyllene common to the three phytophysiognomies. Among the studied areas, the resin collection varied from 2.652 g to 20.263 g, while the essential oil yield varied from 2.216 % to 11.764 %. A concentration range of 0.60 % to 84.57 % was recorded among the compounds in the three study areas. There was variation in chemical composition both among phytophysiognomies and among individuals from the same location, where β-caryophyllene showed to be the majority for all areas studied, being present in all individuals from Cerradão, Carrasco and Humid Forest. Graphical Abstract


Introduction
Copaifera langsdorffii Desf. is frequently used in folk medicine and the pharmaceutical industry, notable mainly for being a producer of oil-resin, a secondary metabolite extracted from the stem with phytotherapeutic effects of great economic value (Veiga Junior and Pinto 2002;Stupp et al. 2008;Nisgoski et al. 2012;Gama and Nascimento 2019), arousing interest in scientific research that proves the citations of uses by communities.
This species has a wide distribution, being found in Brazil, Paraguay, Argentina and Bolivia (GBIF 2021). In Brazil it is found throughout the territory (Costa 2020), in phytophysiognomies such as Campo Rupestre, Cerrado (lato sensu), Riparian Forest or Gallery, Terra Firme Forest, Semideciduous Seasonal Forest and Ombrophilous Forest (Rainforest), and in anthropized areas (Costa 2020).
In the Chapada do Araripe region, C. langsdorffii can be found in the phytophysiognomies of Cerradão, Carrasco and Humid Forest (Cartaxo et al. 2010;Ribeiro et al. 2014;Saraiva et al. 2015;Santos et al. 2019). This species has great medicinal potential, being of large importance for communities, and is indicated for the treatment of various health problems such as flu, coughs, expectorant, colds, bone problems, healing, inflammation, diuretic and allergies (Veiga Junior and Pinto 2002;Pasa et al. 2005;Ribeiro et al. 2014;Saraiva et al. 2015;Macêdo et al. 2018).
The numerous therapeutic indications of C. langsdorffii are linked to the presence of an active ingredient. Understanding the variability of chemical composition in different phytophysiognomies can help in expanding knowledge about ecological interactions of the plant with its environment (Gobbo-Neto and Lopes 2007), also indicating the best environment for collection in order to obtain desirable concentrations of chemical compounds that suit the needs of the market and communities (Figueiredo et al. 2009).
Differences in chemical composition as a function of the collection environment were reported for different species, including C. langsdorffii (Almeida et al. 2014;Oliveira et al. 2017). In a review of C. langsdorffii Santos et al. (2022) found that there was variation in the chemical composition of the essential oil both for the same region and between different Brazilian regions. This shows the great variability of the chemical composition of this species caused by the specificities of each environment.
Therefore, considering the medicinal and economic importance of C. langsdorffii for communities coupled with the lack of scientific information related to chemical data in different vegetational types, this study aims to analyze the chemical profile of the essential oils extracted from the stem resin of C. langsdorffii in areas of Cerradão, Carrasco, and Humid Forest in the Northeast of Brazil in order to investigate the chemical variation of the species in different areas, and indicate in which environment the species produces highest chemical content.

Results and discussion
2.1. Chemical profile and essential oil yield of Copaifera langsdorffii Desf. in different phytophysiognomies Twenty-six different chemical constituents ( Figure S1) were identified in the essential oil extracted from C. langsdorffii trunk resin, of which 12 were present in Cerradão, 15 in Carrasco, and 18 in Humid Forest (Table S1). The common compounds in the Cerradão, Carrasco and Humid Forest phytophysiognomies were b-bisabolene, caryophyllene oxide, c-muurolene, a-caryophyllene and b-caryophyllene. The concentration of each constituent varied between areas and individuals (Table S1). Similar concentrations are recorded for these compounds present in the essential oil of Copaifera langdorffii resin in studies developed in Brazil by Alencar et al. (2015), Gramosa and Silveira (2005) and Oliveira et al. (2017).
Among the compounds in the analyzed oil samples, a variation of 0.60% to 84.57% in the concentration of the essential oils was recorded (Table S1). These concentrations were both observed in the Humid Forest, the lowest being for b-elemene and (1 R)-2,6,6-trimethylbicyclo[3.1.1]hept-2-ene, and the highest for b-caryophyllene (Table S1). Volatile extractions from the leaves (Almeida et al. 2014), and the resin (Oliveira et al. 2017) of the stem of C. langsdorffii were reported in the chemical composition of this species. This change in the chemical composition of the species in different phytophysiognomies may be related to ecophysiological events such as seasonality and temperature, as well as factors such as soil constitution, genetics, adaptive and evolutionary events, geographic area, and different developmental stages among individuals and populations (Wink 2003;Figueiredo et al. 2008;Teles et al. 2013).
Among the areas, the collected resin varied from 2.652 g to 20.263 g, while the essential oil yield varied from 2.216% to 11.764% (Table S2). The variation in resin and essential oil yield are in accordance with that found by Oliveira et al. (2017) and Gelmini et al. (2013) for C. langsdorffii. The authors observed values for the resin between 1.10 g and 34.70 g, and for the yield of essential oil between 2.15 % and 28.80 %.
In the Humid Forest, the amount of resin collected was 15.672 g, 20.263 g and 12.784 g, giving 4.217 %, 2.270 % and 7.227 % of essential oil for the three individuals analyzed, respectively. Carrasco, on the other hand, had 8.792 g, 14.341 g and 10.042 g of resin, giving 5.937 %, 5.376 % and 6.293 %, respectively. In Cerradão the resin collection was 4.081 g, 5.594 g and 2.652 g, giving 7.865 %, 2.216 % and 11.764 % essential oil, respectively (Table S2). In areas of Conserved and Anthropized Cerrado, Oliveira et al. (2017) obtained, for the same month of collection (February), 10.6 g and 3.1 g of resin, yielding 23.2 % and 11.6% essential oil, respectively. Almeida et al. (2014), on the other hand, using the leaves of this species, obtained a variation for the semideciduous seasonal forest of 0.11 % to 0.38 %, while in the Cerrado strictu sensu, a variation of 0.45 % to 0.60 % was observed. Almeida et al. (2016), also working with the leaves in Cerrado vegetation, obtained an essential oil yield ranging from 0.03 % to 0.05 %.
The yield of essential oil for the Cerradão, Carrasco, and Humid Forest areas is not related to the amount of oil-resin used in the extraction of this mixture. For the Cerradão, in a resin variation of 2.652 g to 5.594 g, 12 constituents were detected in the Carrasco, between 8.792 g to 14.341 g of resin presented 15 compounds as for Humid Forest, the resin collection varied between 12.784 g to 20.263 g, and its essential oil presented 18 compounds (Table S2).
Statistically, there were no significant differences between the yields of essential oils obtained and collected in the different phytophysiognomies (p ¼ 0.397). On average, the samples show only small differences higher oil yields were verified in the Cerradão, where the lowest mass of oil resin was obtained, but the yields were the most considerable, different from the collections carried out in the Humid Forest, where the highest mass of oil resin was obtained and the yield showed the lowest average. In a comparative analysis between Humid Forest and Cerradão, although there was no significant difference in oil yield (p > 0.05) when compared to each other, the lowest value of p ¼ 0.329 was verified. Between Cerradão and Carrasco a value of p ¼ 0.850 was verified and between Carrasco and Humid Forest p ¼ 0.602, showing that there is not a significant difference between the evaluated data.
Therefore, qualitative and quantitative variation is observed in the chemical composition of C. langsdorffii in the Cerradão, Carrasco, and Humid Forest phytophysiognomies, with differences in the number of compounds recorded in each environment, as well as in the concentration of these compounds, although statistically not considered relevant. Further studies are needed in order to determine which factors influence these variations.

Conclusion
The distinct phytochemical profiles presented in the essential oil of Copaifera langsdorffii Desf. resin, in vegetation formations of Cerradão, Carrasco and Humid Forest, show a variation among phytophysiognomies, as well as among individuals from the same site. This diversity in chemical composition is responsible for the biological activities conferred to this species. The compound b-caryophyllene proved to be the majority for all areas studied and it was present in all individuals from Cerradão, Carrasco, and Humid Forest. Among the phytophysiognomies analyzed, Cerradão is considered the most promising, both for further studies with C. langsdorffii, as well as for the elaboration of medicines, since it offers a higher yield in its essential oil.

Acknowledgment
The CAPES (Coordination for the Improvement of Higher Education Personnel) for the bursary given to first author.

Disclosure statement
No potential conflict of interest was reported by the authors.

Funding
TThe CAPES (Coordination for the Improvement of Higher Education Personnel) for the bursary given to first author.