Geographical variation in the chemical composition, anti-inflammatory activity of the essential oil, micromorphology and histochemistry of Schinus terebinthifolia Raddi

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Ethnopharmacological relevanceSchinus terebinthifolia Raddi (Anacardiaceae) is rich in essential oil, distinguished by a predominance of monoterpenes and sesquiterpenes, it being widely used in traditional medicine for the treatment of inflammations. Aim of studyThis study's objective was to investigate the chemical composition of the essential oil of S. terebinthifolia (EOST) collected in six states of Brazil, evaluate its anti-inflammatory effects in mice, and analyze the histochemistry and micromorphology of leaves and stems. Materials and methodsAerial parts of S. terebinthifolia were collected in six states of Brazil, and the essential oil was extracted by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC–MS). The histochemistry and micromorphology of leaves and stems were performed using standard reagents, light and field emission scanning electron microscopy, beyond energy-dispersive X-ray spectroscopy. The EOST were evaluated for anti-inflammatory activity and hyperalgesia using the carrageenan-induced paw edema methodology. ResultsThe EOST showed variation across the six states in its yield (0.40%–0.86%) and chemical composition: hydrocarbon monoterpenes (28.76%–47.73%), sesquiterpenes, (31.43%–41.76%), oxygenated monoterpenes (14.31%–19.57%), and oxygenated sesquiterpenes (4.87%–14.38%). Both α-pinene and limonene were predominant constituents of essential in five regions, except for one state where α-phellandrene and limonene were the dominant components. A comprehensive description of the leaf and stem micromorphology and histochemistry was performed. In the in vivo testing, all EOST samples exerted antiedematogenic and anti-hyperalgesic effects, when tested in a carrageenan-induced paw inflammation (mechanical and thermal hyperalgesia) model with oral doses of 30 mg/kg. ConclusionOur results indicate that the EOST samples collected in six Brazilian states differed in their chemical composition but not their anti-inflammatory and antihyperalgesic effects, which was correlated with the synergistic effect of its components, collaborating the etnhopharmacologycal use of this plant due to its an anti-inflammatory effect. Also, micromorphology and histochemistry of leaves and stems presented in this study provide anatomical and microchemical information, which aids species identification.