Chemical Composition and Acaricidal Activity of Essential Oils from Croton rhamnifolioides Pax and Hoffm. in Different Regions of a Caatinga Biome in Northeastern Brazil

Abstract

Essential oils from the stems and leaves of Croton rhamnifolioides Pax and Hoffm from three locations in the semiarid region of the state of Pernambuco, Brazil, were investigated. Seventy constituents were identified by gas chromatography-mass spectrometry (GC-MS) of the oils from the municipalities of Serra Talhada (ST), Buíque (BU) and Floresta (FL), representing 97.99±1.03% and 97.12±0.94% of the leaf and stem oils in ST, 97.42±0.77% and 97.50±0.68% in BU and 98.30±0.84% and 97.10±0.80% in FL. Sesquiterpenes were predominant in the oils. β-caryophyllene was the main constituent in all locations (ST: 22.45±0.70% in leaf oil and 25.80±0.63% in stem oil; BU: 33.34±0.56% in leaf oil and 38.45±0.95% in stem oil; FL: 26.67±0.53% in leaf oil and 29.50±0.86% in stem oil). Bicyclogermacrene (ST: 11.65±0.75% in leaf oil and 9.34±0.55% in stem oil; FL: 10.58±0.38% in leaf oil and 9.90±0.66% in stem oil) and 1,8-cineole (BU: 10.45±0.56% in leaf oil and 6.50±0.26% in stem oil) were also found in significant proportions. According to the principal component analysis, the chemical composition of the essential oils from C. rhamnifolioides varied across geographic locations. All oils demonstrated acaricidal action against T. urticae. The best result was observed for the BU oil, which was nine-fold and 14-fold more toxic as well as fourfold and 11-fold more repellent that the oils from ST and FL, respectively.