Consumo actual de edulcorantes naturales (beneficios y problemática): Stevia / Current consumption of natural sweeteners (benefits and problems): Stevia

La estevia [Stevia rebaudiana (Bertoni)] es un arbusto de tipo perenne de la familia de las Asteraceas que crece en áreas tropicales y subtropicales de Suramérica. Hoy en día, su cultivo se ha extendido a otras regiones del mundo, incluyendo Canadá y algunas partes de Asia, Europa y México, donde sus hojas se han utilizado tradicionalmente como edulcorante natural durante cientos de años. En la actualidad, el uso potencial y las implicaciones prácticas de la estevia como un edulcorante se muestran en una serie de alimentos procesados, ya que contiene glucósidos de esteviol como ingrediente activo, que puede ser bajo o no calórico, y hasta 100-300 veces más dulce que la sacarosa. Además, las hojas secas de estevia contienen también minerales, vitaminas, compuestos fenólicos, flavonoides y otros compuestos antioxidantes, con propiedades antimicrobianas y antioxidantes. Stevia acumula hasta un 30 % de los glucósidos de esteviol (SGs por su sigla en inglés) del peso seco de las hojas. El esteviósido y el rebaudiósido A son las principales SGs. Desde diciembre de 2011, los SGs (E 960) se han autorizado como aditivo alimentario y edulcorante en Estados Unidos. Su uso en diversas categorías de alimentos está regulado como por ejemplo en suplementos alimenticios y alimentos dietéticos para propósitos médicos especiales y control de peso. Sin embargo, la información ofrecida al consumidor es engañosa y dista de ser confiable. Este artículo ofrece al público interesado, datos que deben de ser evaluados al comprar productos adicionados con estevia (AU).

Stevia [Stevia rebaudiana (Bertoni)] is a perennial shrub belonging to the Asteraceae family that grows in tropical and subtropical areas of South America. Today its cultivation has spread to other regions of the world, including Canada and some parts of Asia, Europe and México, where its leaves have been used traditionally as a natural sweetener for hundreds of years. Nowadays, the potential use and practical implications of Stevia as a sweetener are shown in a number of processed foods, because it contains steviol-glycosides, which are low- or non-caloric ingredients, up to 100­300 times sweeter than sucrose. In addition, dry Stevia leaves also contain minerals, vitamins, phenolic compounds, flavonoids and other antioxidant compounds, with antimicrobial and antioxidant properties. Stevia accumulates up to 30% of diterpenoid steviol glycosides (SGs) of the leaf dry weight. Stevioside and rebaudioside A are the major SGs. Since December 2011, SGs (E 960) have been permitted for use as food additive and a sweetener in the United States. Its use in various food categories is regulated, e.g. food supplements and dietary foods for special medical purposes and weight control. However, the information offered to the consumers is misleading and far from reliable. This article offers the interested public, data that should be evaluated when buying products added with Stevia (AU).

Consumo actual de edulcorantes naturales (beneficios y problemática): Stevia / Current consumption of natural sweeteners (benefits and problems): Stevia

La estevia [Stevia rebaudiana (Bertoni)] es un arbusto de tipo perenne de la familia de las Asteraceas que crece en áreas tropicales y subtropicales de Suramérica. Hoy en día, su cultivo se ha extendido a otras regiones del mundo, incluyendo Canadá y algunas partes de Asia, Europa y México, donde sus hojas se han utilizado tradicionalmente como edulcorante natural durante cientos de años. En la actualidad, el uso potencial y las implicaciones prácticas de la estevia como un edulcorante se muestran en una serie de alimentos procesados, ya que contiene glucósidos de esteviol como ingrediente activo, que puede ser bajo o no calórico, y hasta 100-300 veces más dulce que la sacarosa. Además, las hojas secas de estevia contienen también minerales, vitaminas, compuestos fenólicos, flavonoides y otros compuestos antioxidantes, con propiedades antimicrobianas y antioxidantes. Stevia acumula hasta un 30 % de los glucósidos de esteviol (SGs por su sigla en inglés) del peso seco de las hojas. El esteviósido y el rebaudiósido A son las principales SGs. Desde diciembre de 2011, los SGs (E 960) se han autorizado como aditivo alimentario y edulcorante en Estados Unidos. Su uso en diversas categorías de alimentos está regulado como por ejemplo en suplementos alimenticios y alimentos dietéticos para propósitos médicos especiales y control de peso. Sin embargo, la información ofrecida al consumidor es engañosa y dista de ser confiable. Este artículo ofrece al público interesado, datos que deben de ser evaluados al comprar productos adicionados con estevia (AU).

Stevia [Stevia rebaudiana (Bertoni)] is a perennial shrub belonging to the Asteraceae family that grows in tropical and subtropical areas of South America. Today its cultivation has spread to other regions of the world, including Canada and some parts of Asia, Europe and México, where its leaves have been used traditionally as a natural sweetener for hundreds of years. Nowadays, the potential use and practical implications of Stevia as a sweetener are shown in a number of processed foods, because it contains steviol-glycosides, which are low- or non-caloric ingredients, up to 100­300 times sweeter than sucrose. In addition, dry Stevia leaves also contain minerals, vitamins, phenolic compounds, flavonoids and other antioxidant compounds, with antimicrobial and antioxidant properties. Stevia accumulates up to 30% of diterpenoid steviol glycosides (SGs) of the leaf dry weight. Stevioside and rebaudioside A are the major SGs. Since December 2011, SGs (E 960) have been permitted for use as food additive and a sweetener in the United States. Its use in various food categories is regulated, e.g. food supplements and dietary foods for special medical purposes and weight control. However, the information offered to the consumers is misleading and far from reliable. This article offers the interested public, data that should be evaluated when buying products added with Stevia (AU).

New seminal variety of Stevia rebaudiana: Obtaining fractions with high antioxidant potential of leaves.

The aim of this study was to determine the composition and antioxidant potential of leaves of a new variety of Stevia rebaudiana (Stevia UEM-13). Stevia leaves of UEM-13 contain rebaudioside A as the main glycoside, while most wild Stevia plants contain stevioside. Furthermore can be multiplied by seed, which reduces the cost of plant culture techniques as other clonal varieties are multiplied by buds, requiring sophisticated and expensive seedling production systems. Ethanol and methanol were used in the extraction to determine the bioactive compounds. The methanolic extract was fractionated sequentially with hexane, chloroform, ethyl acetate and isobutanol, and the highest concentration of phenolic compounds and flavonoids was obtained in the ethyl acetate fraction (524.20 mg galic acid equivalent/g; 380.62 µg quercetin equivalent/g). The glycoside content varied greatly among the fractions (0.5% - 65.3%). Higher antioxidant potential was found in the methanol extract and the ethyl acetate fraction with 93.5% and 97.32%, respectively. In addition to being an excellent source for obtaining of extracts rich in glycoside, this new variety can also be used as raw material for the production of extracts or fractions with a significant amount of antioxidant activity and potential to be used as additives in food.

New seminal variety of Stevia rebaudiana: Obtaining fractions with high antioxidant potential of leaves

ABSTRACT The aim of this study was to determine the composition and antioxidant potential of leaves of a new variety of Stevia rebaudiana (Stevia UEM-13). Stevia leaves of UEM-13 contain rebaudioside A as the main glycoside, while most wild Stevia plants contain stevioside. Furthermore can be multiplied by seed, which reduces the cost of plant culture techniques as other clonal varieties are multiplied by buds, requiring sophisticated and expensive seedling production systems. Ethanol and methanol were used in the extraction to determine the bioactive compounds. The methanolic extract was fractionated sequentially with hexane, chloroform, ethyl acetate and isobutanol, and the highest concentration of phenolic compounds and flavonoids was obtained in the ethyl acetate fraction (524.20 mg galic acid equivalent/g; 380.62 µg quercetin equivalent/g). The glycoside content varied greatly among the fractions (0.5% - 65.3%). Higher antioxidant potential was found in the methanol extract and the ethyl acetate fraction with 93.5% and 97.32%, respectively. In addition to being an excellent source for obtaining of extracts rich in glycoside, this new variety can also be used as raw material for the production of extracts or fractions with a significant amount of antioxidant activity and potential to be used as additives in food.

Phylogeny and biogeography of the genus Stevia (Asteraceae: Eupatorieae): an example of diversification in the Asteraceae in the new world.

The genus Stevia comprises approximately 200 species, which are distributed in North and South America, and are representative of the species diversity of the Asteraceae in the New World. We reconstructed the phylogenetic relationships using sequences of ITS and cpDNA and estimated the divergence times of the major clade of this genus. Our results suggested that Stevia originated in Mexico 7.0-7.3 million years ago (Mya). Two large clades, one with shrub species and another with herb species, were separated at about 6.6 Mya. The phylogenetic reconstruction suggested that an ancestor of Stevia was a small shrub in temperate pine-oak forests and the evolutionary change from a shrub state to a herb state occurred only once. A Brazilian clade was nested in a Mexican herb clade, and its origin was estimated to be 5.2 Mya, suggesting that the migration from North America to South America occurred after the formation of the Isthmus of Panama. The species diversity in Mexico appears to reflect the habitat diversity within the temperate pine-oak forest zone. The presence of many conspecific diploid-polyploid clades in the phylogenetic tree reflects the high frequency of polyploidization among the perennial Stevia species.

Antioxidant capacity of leaf extracts from two Stevia rebaudiana Bertoni varieties adapted to cultivation in Mexico.

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 ß-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 Cu²âº and between 52.2-54.4% for Fe²âº, 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.

La reciente introducción del cultivo de Stevia rebaudiana Bertoni en México ha ganado interés debido a su potencial uso como fuente de edulcorantes no calóricos, pero otras propiedades de esta planta aun requieren de estudios. Extractos de hojas de dos variedades de S. rebaudiana Bertoni adaptadas al cultivo en México fueron evaluados en cuanto a su contenido de algunos fitoquímicos y sus propiedades antioxidantes. El contenido de pigmentos, fenoles totales y flavonoides en los extractos, osciló entre 17.7-24.3 mg/g, 28.7-28.4 mg/g, y 39.3-36.7 mg/g, respectivamente. La variedad "Criolla" exhibió los mayores contenidos de pigmentos y flavonoides. La capacidad antioxidante equivalente de Trolox osciló entre 618.5-623.7 mM/mg y el ensayo de decoloración del radical DPPH osciló entre 86.4-84.3%, no observándose diferencias significativas entre ambas variedades. La inhibición de la decoloración del -caroteno osciló entre 62.3-77.9%, siendo mayor en la variedad "Criolla". El poder reductor osciló entre 85.2-86%, las capacidades quelantes de cobre y hierro oscilaron entre 57.3-59.4% y 52.2-54.4%, respectivamente, no observándose diferencias significativas entre ambas variedades. En conclusión, los resultados de este estudio demuestran que los compuestos de naturaleza polar obtenidos durante la extracción, tales como pigmentos clorofílicos, carotenoides, compuestos fenólicos y flavonoides contribuyen a la actividad antioxidante. Las hojas de S. rebaudiana Bertoni podrían ser empleadas no solo como fuente de edulcorantes no calóricos, sino también como fuente de antioxidantes de origen natural.

Actividad antimicrobiana del extracto en metanol de Stevia Rebaudiana sobre bacterias Gram-negativas (Escherichia coli, Enterobacter cloacae) y Gram-positivas (Streptococcus mutans, Staphylococcus aureus) contaminantes de cavidad oral e importantes en enfermedad periodontal / Antimicrobial activity of Stevia rebaudiana extract, in methanol, on Gram-negative bacteria (Escherichia coli, Enterobacter cloacae) and Gram-positive bacteria (Streptococcus mutans, Staphylococcus aureus) contamining the oral cavity and relevant in periodontal disease

Objetivo: determinar la actividad antimicrobiana del extracto en metanol de Stevia rebaudiana sobre bacterias gram negativas y gram positivas, contaminantes de cavidad oral e importantes en enfermedad periodontal. Materiales y métodos. Estudio experimental (fase I) cuyo objetivo era la Stevia rebaudiana. Se realizó la obtención de plantas y microorganismos, preparación de los extractos y ensayos microbiológicos. Se busca estudiar la actividad antimicrobiana del extracto en metanol de hojas de stevia rebaudiana bertoni pulverizada. Los extractos stevia rebaudiana presentaron, en estudios anteriores, actividad sobre microorganismos cariogénicos (S. mutans y L. acidophilus); se cree que los extractos propuestos tengan una gran actividad sobre los microorganismos relacionados con enfermedad periodontal. Resultados y conclusiones. El solvente metanol indica que por sí sola la stevia rebaudiana no no tuvo acción inhibitoria sobre los dos microorganismos gram-negativos. La acción inhibitoria sobre los microorganismos se inicia a partir de 200 mg/ml.