UPLC-PDA-MS evaluation of bioactive compounds from leaves of Ilex paraguariensis with different growth conditions, treatments and ageing

Teas from Mate have been widely consumed for centuries in Brazil, Argentina, Paraguay, and Uruguay. We now determine how age, growth conditions and post-harvesting processes of leaves from Ilex paraguariensis affect the concentration of bioactive compounds and their antioxidant capacity. Phenolics, xanthines, and carbohydrates were identified and quantified by electrospray ionisation mass spectrometry (ESI-MS) and ultra performance liquid chromatography (UPLC), which dramatically reduces the time for each analysis (<3 min). On average, sun-exposed (monoculture) leaf extracts exhibited higher levels of bioactive compounds as compared to shaded (forest grown) ones. PCA (principal component analysis) analysis of all the samples indicated that those obtained after blanching and drying contained more phenolics and a smaller concentration of xanthine than those in natura. The oxidised leaves had lower concentrations of phenolics, and consequently a decline in antioxidant activity. No differences were found based on the leaf age. (C) 2011 Elsevier Ltd. All rights reserved.