Fatty acid profile of stinging nettle leaves: application of modern analytical procedures for sample preparation and analysis†
Stinging nettle is a perennial plant with significant biological activity and a long history of application in folk medicine and as food. Its activity is ascribed to its chemical composition. Its leaves contain different classes of compounds including fatty acids. This study deals with the isolation of fatty acids in stinging nettle leaves using a rapid extraction system for solid–liquid extraction (Soxtherm) with petroleum ether as the solvent. The obtained results indicate that the saturated fatty acids are more abundant than unsaturated fatty acids. The most abundant fatty acids are C12 : 0 (20.94%, 348.07 μg g−1), C16 : 0 (18.57%, 309.06 μg g−1), and C18 : 1 (13.16%, 219.44 μg g−1), whereas the fatty acid with the lowest content is C17 : 1 (0.13%, 2.20 μg g−1). Prior to analysis, the method is validated to obtain accurate and precise results. The limit of detection and limit of quantification are 0.012–0.038% and 1.67–7.03%, whereas the precision and accuracy are 83–126% and 1.67–7.03%, respectively. The validation parameters are >0.999, 0.011–0.032%, 0.012–0.038%, 1.67–7.03%, 83–126%, 0.22–5.24%, and 0.38–6.94% for linearity, limit of detection, limit of quantitation, precision, accuracy, inter-day precision, and intra-day precision, respectively, confirming the suitability of this method for fatty acid analysis.