摘要：La reciente introduccion del cultivo de Stevia rebaudiana Bertoni en Mexico ha ganado interes debido a su potencial uso como fuente de edulcorantes no caloricos, pero otras propiedades de esta planta aun requieren de estudios. Extractos de hojas de dos variedades de S. rebaudiana Bertoni adaptadas al cultivo en Mexico fueron evaluados en cuanto a su contenido de algunos fitoquimicos y sus propiedades antioxidantes. El contenido de pigmentos, fenoles totales y flavonoides en los extractos, oscilo entre 17.7-24.3 mg/g, 28.7-28.4 mg/g, y 39.3-36.7 mg/g, respectivamente. La variedad "Criolla" exhibio los mayores contenidos de pigmentos y flavonoides. La capacidad antioxidante equivalente de Trolox oscilo entre 618.5-623.7 mM/mg y el ensayo de decoloracion del radical DPPH oscilo entre 86.4-84.3%, no observandose diferencias significativas entre ambas variedades. La inhibicion de la decoloracion del β-caroteno oscilo entre 62.3-77.9%, siendo mayor en la variedad "Criolla". El poder reductor oscilo entre 85.2-86%, las capacidades quelantes de cobre y hierro oscilaron entre 57.3-59.4% y 52.2-54.4%, respectivamente, no observandose diferencias significativas entre ambas variedades. En conclusion, los resultados de este estudio demuestran que los compuestos de naturaleza polar obtenidos durante la extraccion, tales como pigmentos clorofilicos, carotenoides, compuestos fenolicos y flavonoides contribuyen a la actividad antioxidante. Las hojas de S. rebaudiana Bertoni podrian ser empleadas no solo como fuente de edulcorantes no caloricos, sino tambien como fuente de antioxidantes de origen natural.
其他摘要：The recent introduction of the cultivation of Stevia rebaudiana Bertoni in Mexico has gained interest for its potential use as a non-caloric sweetener, but some other properties of this plant require studies. Extracts from two varieties of S. rebaudiana Bertoni adapted to cultivation in Mexico were screened for their content of some phytochemicals and antioxidant properties. Total pigments, total phenolic and flavonoids contents of the extracts ranged between 17.7-24.3 mg/g, 28.7-28.4 mg/g, and 39.3-36.7 mg/g, respectively. The variety "Criolla" exhibited higher contents of pigments and flavonoids. Trolox equivalent antioxidant capacity ranged between 618.5-623.7 mM/mg and DPPH decolorization assay ranged between 86.4-84.3%, no significant differences were observed between varieties. Inhibition of â-carotene bleaching ranged between 62.3-77.9%, with higher activity in the variety "Criolla". Reducing power ranged between 85.2-86% and the chelating activity ranged between 57.3-59.4% for Cu2+ and between 52.2-54.4% for Fe2+, no significant differences were observed between varieties. In conclusion, the results of this study showed that polar compounds obtained during the extraction like chlorophylls, carotenoids, phenolic compounds and flavonoids contribute to the antioxidative activity measured. The leaves of S. rebaudiana Bertoni could be used not only as a source of non-caloric sweeteners but also naturally occurring antioxidants.
