Biological activity of extracts from guayusa leaves (Ilex guayusa Loes.) obtained by supercritical CO2 and ethanol as cosolvent

Abstract

To the best of our knowledge, this is the first study to investigate the biological activities and main constituents of extracts from guayusa leaves (Ilex guayusa Loes.) by using supercritical CO2 as solvent and ethanol as cosolvent at different conditions of pressure and temperature and comparing them with Soxhlet technique. The global yield (X0); total phenolic content (TPC), assessed by Folin–Ciocalteu reagent; in vitro antioxidant capacity, by both ABTS•+ and DPPH methods; antimicrobial activity; and the main phytochemicals, based on gas chromatography-mass spectrometry, of the extracts were tested. X0, TPC, and antioxidant capacity were dependent on technique or solvent used and increased when ethanol was used as cosolvent. Antifungal activity was demonstrated against T. rubrum, T. mentagrophytes, M. gypseum and M. canis. The main phytochemicals were caffeine, squalene and α-amyrin. Therefore, known for its caffeine content, guayusa extracts obtained by supercritical fluid extraction showed important nutraceutical ingredients.