Avaliação do perfil metabolômico de Cymbopogon winterianus por ressonância magnética nuclear e métodos cromatográficos

Abstract

The species selected for study in this work was citronella (Cymbopogon winterianus), popularly known as Citronella de java and Citronella grass. It is an aromatic herb belonging to the Poaceae family, native to tropical and subtropical areas of Asia, India, Indonesia and cultivated in South America. The objective of this work was to evaluate the authenticity of commercial citronella essential oils by evaluating the chemical composition of these oils compared with the oil of the Cymbopogon winterianus species identified botanically, using Gas Chromatography Coupled with Mass Spectrometry (GC-MS) and Nuclear Magnetic Resonance (NMR), including quantitative. The hydrodistillation of the aerial parts of C. winterianus resulted in essential oils, with approximately 0.3% yield. The characterization of the extracted oil and commercial oils was carried out by Gas Chromatography Coupled to Mass Spectrometry (GC-MS), resulting in the identification of a total of 15 compounds, the majority of which were: citronellal, citronellol and geraniol. It was obtained for OECTUFC-2 (citronellal (49.74%), geraniol (22.89%) and citronellol (9.11%)); o OECTECS (citronellal (46.91%), geraniol (21.49%) and citronellol (13.60%)); OECTNAT (citronellal (31.15%), geraniol (25.93%) and citronellal (13.11%)) and OECTVIA (citronellal (50.49%), geraniol (23.29%) and citronellal (10.79%)). For characterization by 1H NMR, the signals indicating the majority components were: 3.66-3.79 and 5.06-5.30 ppm for citronellol; 9.80 and 5.06-5.30 ppm for citronellal, and at 4.16; 5.06-5.30 and 5.40-5.52 ppm for geraniol. Quantification of the majority components was also carried out by qNMR in mg/g and the following were obtained, for example, for geraniol: OECTUFC-2 (255.8 mg/g), OECTECS (220.9 mg/g), OECTNAT (272.1 mg/g) and OECTVIA (233.1 mg/g). The essential oil of the botanically identified species of C. winterianus and the commercial oils studied presented similar composition and quantification data, which corroborates the use of quantitative NMR as an alternative method in the authentication of commercial essential oils.