The use of guayusa (Ilex guayusa Loes.) leaves as functional food has increase recently. This work discusses the antioxidant activity and volatile compounds of guayusa leaves extract and fractions. The methanol crude extract was obtained by maceration, subsequently hexane, chloroform, ethyl acetate, and aqueous fractions were collected by solvent-solvent partition.Total phenolic content (TPC), total flavonol/flavone content (TFC), 2,2-diphenyl-1picrylhydrazyl (DPPH) radical scavenging activity, and ferric reducing antioxidant power (FRAP) were measured by ultraviolet-visible (UV-Vis) spectrophotometry. The results revealed that ethyl acetate fraction showed highest inhibition against DPPH radical (93.86±0.95%) at 500 µg/mL, and reduce the ferric-tripyridyltriazine complex (Fe 3+ -TPTZ) at 1619.81 mg trolox equivalent (TE)/g, followed by aqueous fraction. This bioactivity could be related to phenolic acids, flavones and flavonols content, as well as the caffeine, dodecanoic acid isopropyl ester, caffeic acid, and malic acid identified by gas chromatography-mass spectrometry (GC-MS). These findings support the antioxidant properties of this plant material.
En este trabajo se discute la influencia del secado al aire (AD), el horno de convección (CO) y el secado solar (SOD) sobre las propiedades físicas y químicas de las hojas de Ilex guayusa. Seestimaron las cenizas totales (%), las cenizas insolubles en ácido (%), las cenizas solubles en agua (%), la humedad residual (%) y el contenido de cafeína (%). Además, se analizó la presencia los alcaloides, flavonoides, azúcares reductores, saponinas, esteroides, quinonas, grasas, fenoles y taninos en extractos de hojas secas. Los resultados revelaron que los parámetros del análisis físico no se vieron afectados por las técnicas de secado. La mayor cantidad de metabolitos secundarios se detectó en el extracto etanólico y acuoso. En general, las hojas secadas al horno de convección mostraron el mayor contenido de cafeína (3,71%) y el menor tiempo de secado (13 h) en comparación con los otros métodos de secado empleados. Los resultados obtenidos revelaron un método rápido para secar hojas de Ilex guayusa sin alterar el contenido de componentes bioactivos beneficiosos para la salud, estudios que no han sido reportados.
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