Avaliação sazonal dos constituintes do óleo essencial da espécie Poincianella pyramidalis (Tul) LP Queiroz (Fabaceae)

Abstract

The use of plants is part of humanity's evolution, and they are seen as the first known food and therapeutic resources. Poincianella pyramidalis [Tul.] L. P. Queiroz is a species that is easily found in different states of the Northeast and can be widely exploited as a source of income, due to its various uses: forage, therapeutic, fuel, among others. Due to its resistance to drought, the species is used as animal feed during periods of drought. However, there are reports that after the rains, which usually occur between November and February, it has a strong odor, which leads animals to reject foraging with the plant. Based on this, this research sought to carry out a chemical study of the P. pyramidalis species with a focus on identifying the volatile components of its essential oil, taking seasonality into account in order to assess whether or not it interferes with the composition of these components. The plant material used was collected from the experimental farm of the CCA/UFPB, in São João do Cariri - PB. The leaves of the P. pyramidalis species were extracted in the last week of each month, and the period under analysis was from July to December 2022. The hydrodistillation technique was used to extract the essential oils. The extractions were carried out in triplicate. The analysis was carried out using gas chromatography coupled with a mass spectrometer, observing the variation in composition to determine the main components present in the species according to the seasonal periods. The results show that the essential oil of the species in question has terpenes as its main components, including monoterpenes, sesquiterpenes and diterpenes. The main component found during the months analyzed was the sesquiterpene (E)-caryophyllene, with predominance and relevance mainly in November and December, the period with the highest rainfall in the locality. Monoterpenes were predominant throughout September, a factor that may be associated with the species' flowering in spring. These compounds are highly volatile, which benefits their attractiveness to pollinators. The majority components that were present in practically every month were (E)-caryophyllene, D-Germacrene, δ-cadinene, α-copaene, (Z)-3,7-dimethyl-1,6,3-octatriene, linalool, caryophyllene oxide, α-humulene and manoyl 13-epi-oxide, all of which have relevant biological activities, such as antibacterial, anti-inflammatory, antioxidant, insecticidal and antimicrobial action, in addition to their mostly spicy and woody odor. This study has brought contributions that help to understand the behavior of the species over the six months of research, but other investigations along the same lines could enrich this knowledge, such as extending the period of seasonal analysis to twelve months, so as to cover other seasons (summer and autumn) to check the composition of the plant's essential oils.