Sensory and physicochemical analysis of honeys of nine stingless bee species of Mexico and Guatemala.

Honeys produced by species other than Apis mellifera are little known. The objective of this study was to carry out sensory and physicochemical analyses of 62 samples to characterize honeys from nine species of stingless bees from Mexico and Guatemala. Analyses were performed at the sensory level and at the physicochemical level. Qualitative and quantitative data were studied using the multivariate non-metric multidimensional scaling (NMDS) statistical technique, with the Gower metric. According to the stress value (p > 0.2), the most significant parameters were at the sensory level, for visual evaluation, physical state, color, and appearance; for olfactory-taste evaluation, elemental sweet and acid tastes; for tactile evaluation, consistency, and crystallization, and for physicochemical evaluation, pH, electrical conductivity and reducing sugars. Data analysis showed that Melipona beecheii honeys formed a defined group, with similar sensory characteristics and physicochemical values, even taking into account their place of origin. Frieseomelitta nigra honeys also showed significant differences with the other honeys analyzed. Our work suggests that the entomological origin is the main factor that determines the characteristics of honey, and that the floral origin is the secondary factor, a hypothesis that should be verified in future works.

Efecto antihipertensivo, antihiperglucemiante y antioxidante de los extractos de Stevia rebaudiana Bertoni (variedad criolla INIFAP C01) en ratas Wistar con síndrome metabólico inducido / Antihypertensive, antihyperglycemic, and antioxidant effects of Stevia rebaudiana Bertoni (creole variety INIFAP C01) extracts on Wistar rats with induced metabolic syndrome

INTRODUCCIÓN: las plantas medicinales han mostrado tener aplicaciones terapéuticas en el tratamiento de diferentes enfermedades, entre ellas las enfermedades crónicas degenerativas presentes en el síndrome metabólico (SM). OBJETIVOS: evaluar el efecto en el control del peso, así como el efecto antihipertensivo, antihiperglucémico y antioxidante, de extractos acuosos y etanólicos de hojas y tallos de Stevia rebaudiana, variedad criolla INIFAP C01, producidas en los municipios de Muna y Mocochá (Yucatán, México). MÉTODOS: se administraron por vía oral extractos acuosos y etanólicos de hojas (HAMU y HEMU, respectivamente) y tallos procedentes de Muna (TAMU y TEMU, respectivamente), así como extractos acuosos y etanólicos de hojas (HAMO y HEMO, respectivamente) y tallos de Mocochá (TAMO y TEMO, respectivamente), a ratas Wistar macho en las que se indujo un SM. Se registraron los pesos y se midieron los niveles de presión arterial (PA) y glucosa en sangre, así como los niveles de malondialdehído (MDA) y superóxido-dismutasa (SOD) en plasma sanguíneo. RESULTADOS: TAMU y HAMO mostraron porcentajes de reducción del peso del 1,91 % y 1,57 %, respectivamente. HEMU y HAMU mostraron porcentajes de reducción de la presión arterial sistólica (PAS) y diastólica (PAD) del 30,47-29,31 % y 36,98-36,69 %, respectivamente. En el test de tolerancia oral a la glucosa (TTOG), HEMU mostró porcentajes de reducción de la glucosa sanguínea del 10,94 % en el día uno y del 14,83 % en el día 30. TEMO y TAMO mostraron una menor concentración de MDA, de 7,0 y 7,3 μM, respectivamente, y HEMU y TEMU mostraron una mayor concentración de SOD, de 1,29 y 1,12 U/mL, respectivamente. CONCLUSIONES: los extractos de S. rebaudiana pueden ayudar a controlar el aumento de peso, disminuir las cifras de presión arterial y la incidencia de diabetes, y reducir el daño oxidativo

INTRODUCTION: medicinal plants have demonstrated therapeutic applications for treating different diseases, including chronic and degenerative diseases associated with metabolic syndrome. OBJECTIVES: to assess the weight control and the antihypertensive, antihyperglycemic and antioxidant effects of aqueous and ethanolic extracts of Stevia rebaudiana (creole variety INIFAP C01) leaves and stems cultivated in the Muna and Mocochá municipalities (Yucatán, México). METHODS: aqueous and ethanolic extracts of leaves (HAMU and HEMU, respectively) and stems (TAMU and TEMU, respectively) from Muna, and aqueous and ethanolic extracts of leaves (HAMO and HEMO, respectively) and stems (TAMO and TEMO, respectively) from Mocochá were orally administered to Wistar male rats induced to metabolic syndrome. Weight, blood pressure, blood sugar levels, malondialdehyde (MDA) levels, and superoxide dismutase (SOD) levels in blood plasma were measured. RESULTS: TAMU and HAMO samples reduced weight by 1.91 % and 1.57 %, respectively. On the other hand, HEMU and HAMU samples reduced systolic (PAS) and diastolic (PAD) blood pressure levels by 29.31-30.47 % and 36.69-36.98 %. In the glucose tolerance test (GTT) HEMU showed a reduction in blood sugar levels of 10.94 % on the first day, and of 14.83 % on day 30. TEMO and TAMO samples showed lower malondialdehyde (MDA) concentrations of 7.0 and 7.3 μM, respectively. HEMU and TEMU showed a higher superoxide dismutase (SOD) concentration of 1.29 and 1.12 U/mL, respectively. CONCLUSIONS: extracts of S. rebaudiana can help to control weight gain, to decrease blood pressure and the incidence of diabetes, and to reduce oxidative damage

[Antihypertensive, antihyperglycemic, and antioxidant effects of Stevia rebaudiana Bertoni (creole variety INIFAP C01) extracts on Wistar rats with induced metabolic syndrome]. / Efecto antihipertensivo, antihiperglucemiante y antioxidante de los extractos de Stevia rebaudiana Bertoni (variedad criolla INIFAP C01) en ratas Wistar con síndrome metabólico inducido.

INTRODUCTION: Introduction: medicinal plants have demonstrated therapeutic applications for treating different diseases, including chronic and degenerative diseases associated with metabolic syndrome. Objectives: to assess the weight control and the antihypertensive, antihyperglycemic and antioxidant effects of aqueous and ethanolic extracts of Stevia rebaudiana (creole variety INIFAP C01) leaves and stems cultivated in the Muna and Mocochá municipalities (Yucatán, México). Methods: aqueous and ethanolic extracts of leaves (HAMU and HEMU, respectively) and stems (TAMU and TEMU, respectively) from Muna, and aqueous and ethanolic extracts of leaves (HAMO and HEMO, respectively) and stems (TAMO and TEMO, respectively) from Mocochá were orally administered to Wistar male rats induced to metabolic syndrome. Weight, blood pressure, blood sugar levels, malondialdehyde (MDA) levels, and superoxide dismutase (SOD) levels in blood plasma were measured. Results: TAMU and HAMO samples reduced weight by 1.91 % and 1.57 %, respectively. On the other hand, HEMU and HAMU samples reduced systolic (PAS) and diastolic (PAD) blood pressure levels by 29.31-30.47 % and 36.69-36.98 %. In the glucose tolerance test (GTT) HEMU showed a reduction in blood sugar levels of 10.94 % on the first day, and of 14.83 % on day 30. TEMO and TAMO samples showed lower malondialdehyde (MDA) concentrations of 7.0 and 7.3 µM, respectively. HEMU and TEMU showed a higher superoxide dismutase (SOD) concentration of 1.29 and 1.12 U/mL, respectively. Conclusions: extracts of S. rebaudiana can help to control weight gain, to decrease blood pressure and the incidence of diabetes, and to reduce oxidative damage.

INTRODUCCIÓN: Introducción: las plantas medicinales han mostrado tener aplicaciones terapéuticas en el tratamiento de diferentes enfermedades, entre ellas las enfermedades crónicas degenerativas presentes en el síndrome metabólico (SM). Objetivos: evaluar el efecto en el control del peso, así como el efecto antihipertensivo, antihiperglucémico y antioxidante, de extractos acuosos y etanólicos de hojas y tallos de Stevia rebaudiana, variedad criolla INIFAP C01, producidas en los municipios de Muna y Mocochá (Yucatán, México). Métodos: se administraron por vía oral extractos acuosos y etanólicos de hojas (HAMU y HEMU, respectivamente) y tallos procedentes de Muna (TAMU y TEMU, respectivamente), así como extractos acuosos y etanólicos de hojas (HAMO y HEMO, respectivamente) y tallos de Mocochá (TAMO y TEMO, respectivamente), a ratas Wistar macho en las que se indujo un SM. Se registraron los pesos y se midieron los niveles de presión arterial (PA) y glucosa en sangre, así como los niveles de malondialdehído (MDA) y superóxido-dismutasa (SOD) en plasma sanguíneo. Resultados: TAMU y HAMO mostraron porcentajes de reducción del peso del 1,91 % y 1,57 %, respectivamente. HEMU y HAMU mostraron porcentajes de reducción de la presión arterial sistólica (PAS) y diastólica (PAD) del 30,47-29,31 % y 36,98-36,69 %, respectivamente. En el test de tolerancia oral a la glucosa (TTOG), HEMU mostró porcentajes de reducción de la glucosa sanguínea del 10,94 % en el día uno y del 14,83 % en el día 30. TEMO y TAMO mostraron una menor concentración de MDA, de 7,0 y 7,3 µM, respectivamente, y HEMU y TEMU mostraron una mayor concentración de SOD, de 1,29 y 1,12 U/mL, respectivamente. Conclusiones: los extractos de S. rebaudiana pueden ayudar a controlar el aumento de peso, disminuir las cifras de presión arterial y la incidencia de diabetes, y reducir el daño oxidativo.

Stevia rebaudiana Bertoni: A Natural Alternative for Treating Diseases Associated with Metabolic Syndrome.

Stevia rebaudiana (SR) is often used by the food industry due to its steviol glycoside content, which is a suitable calorie-free sweetener. Further, both in vitro and in vivo studies indicate that these glycosides and the extracts from SR have pharmacological and therapeutic properties, including antioxidant, antimicrobial, antihypertensive, antidiabetic, and anticancer. This work reviews the antiobesity, antihyperglycemic, antihypertensive, and antihyperlipidemic effects of the majority of glycosides and aqueous/alcoholic extracts from the leaves, flowers, and roots of the SR. These compounds can serve as a natural and alternative treatment for diseases that are associated with metabolic syndrome, thus contributing to health promotion.

Biological activity of Stevia rebaudiana Bertoni and their relationship to health.

The leaves of Stevia rebaudiana Bertoni has nutrients and phytochemicals, which make it an adequate source for the extraction and production of functional food ingredients. Preclinical and clinical studies suggest therapeutic and pharmacological applications for stevia and their extracts because they are not toxic and exhibit several biological activities. This review presents the biological activity of Stevia rebaudiana Bertoni and their relationship to antidiabetic, anticariogenic, antioxidant, hypotensive, antihypertensive, antimicrobial, anti-inflammatory and antitumor activities. Consumption and adverse effects were also reviewed.

Evaluation of the Antihyperglycemic Effect of Minor Steviol Glycosides in Normoglycemic and Induced-Diabetic Wistar Rats.

Steviol glycosides are a family of compounds found in Stevia rebaudiana Bertoni that are responsible for sweetness capacity. The antihyperglycemic effect of the two major steviol glycosides, Rebaudioside A and Stevioside, has been studied and it has been found that despite having the same common structure, only Stevioside exerts an antihyperglycemic effect. Although other steviol derivatives are found in smaller amounts (minor steviol glycosides) in S. rebaudiana, whether or not they possess antihyperglycemic activity has not been evaluated. The aim of this study was to evaluate the antihyperglycemic effect of minor steviol glycosides in normoglycemic and diabetic (streptozotocin/nicotinamide) Wistar rats. Rats were subjected to an intraperitoneal glucose tolerance test (IPGTT) both before and after chronic treatment (28 days). After 6 h of fasting, IPGTT was conducted in pentobarbital-anesthetized rats using 1 g/kg of glucose plus 20 mg/kg of the minor glycoside (Dulcoside A, Rebaudioside B, C, D, or Steviolbioside) or control treatment (distilled water, glibenclamide, or metformin); the blood of the tip of the tail was collected at time 0, 15, 30, 60, and 120 min.; and blood glucose was measured, and its net area under the curve (AUCnet) was calculated. After 28-day chronic oral administration, IPGTT was again performed. Differences were considered significant at P < .05 by one-way ANOVA. Acute intraperitoneal or chronic oral administration of 20 mg/kg of minor steviol glycosides had no antihyperglycemic effect in normoglycemic or induced-diabetic Wistar rats. Considering the dose tested, it is unlikely that these glycosides have an effect on glucose in diabetic or normoglycemic humans.

Nutritional, amylolytic enzymes inhibition and antioxidant properties of bread incorporated with Stevia rebaudiana.

Wheat bread with sucrose content replaced with different levels of stevia extract was compared with traditional wheat bread. The ability to reduce glucose intake was highlighted by performing enzymatic assays using α-amylase and α-glucosidase. Antioxidant activity was measured by determining the scavenging effect on α,α-diphenyl-ß-picrylhydrazyl radical. In comparison with the control, the bread with stevia extract was softer and had lower microbial growth during the shelf-life study. The sensory test showed that the substitution of 50% stevia extract was more acceptable when comparing with all the quality characteristics. Regarding the nutritional contribution, the content of dietary fiber and digestible carbohydrates in the bread with stevia extract was higher and lower respectively, so caloric intake was significantly reduced. The results showed that the biological properties of Stevia rebaudiana extract were retained after the bread making process and that the proposed bread could be suitable as functional food in human nutrition.

Antioxidant capacity of leaf extracts from two Stevia rebaudiana Bertoni varieties adapted to cultivation in Mexico / Capacidad antioxidante de extractos foliares de dos variedades de Stevia Rebaudiana Bertoni adaptadas al cultivo en México

The recent introduction of the cultivation of Steviarebaudiana 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 between618.5-623.7 mM/mg and DPPH decolorization assay ranged between 86.4-84.3%, no significant differences were observed between varieties. Inhibition of β-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 between57.3-59.4% for Cu2+ and between 52.2-54.4% forFe2+, 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 (AU)

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 β-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 (AU)

Desarrollo de una golosina tipo «gomita» reducida en calorías mediante la sustitución de azúcares con Stevia rebaudiana B / Development of a gummy Candy reduced in calories by sugar substitution with stevia rebaudiana B

Las gomitas son golosinas de consumo difundido entre personas de diferentes edades aunque principalmente por los niños. La formulación de este producto requiere azúcar que contribuye a su sabor y consistencia, aunque con el efecto indeseable de incrementar su índice glicémico y calorías provenientes de azúcares simples; se sabe que el consumo de productos con estas dos últimas características están relacionados con la obesidad infantil, la cual es una enfermedad en crecimiento a nivel mundial. La Stevia rebaudiana es una planta que naturalmente contiene glucósidos con alto poder endulzante y que se considera segura para su consumo. El objetivo de este trabajo fue desarrollar una golosina tipo «gomita» reducida en calorías mediante la sustitución de azúcares con Stevia rebaudiana B. y analizar su textura y grado de aceptación. Se elaboraron gomitas con diferente porcentaje de reducción de azúcar (-20, -40, -60, -80 y -100%) y un producto control (100% azúcar), a las cuales se evaluó su desplazamiento y deformación máxima para evaluar la elasticidad, así como la fuerza de ruptura para determinar la resistencia; aquellas gomitas con mejores parámetros de elasticidad y resistencia se les realizaron el análisis proximal y el análisis sensorial con una escala no estructurada aplicada a 90 niños escolares con edades comprendidas entre 6 y 10 años. Se desarrolló una golosina tipo «gomita» reducida en calorías con un porcentaje de sustitución de azúcar de hasta 60% con S. rebaudiana, cuyo nivel de agrado en niños escolares fue estadísticamente igual comparado con la gomita realizada con 100% de azúcar (p<0.05) (AU)

The consumption of gummy candy is widespread among people of different ages but mainly by children. The formulation of this product requires sugar that contributes to their flavor and consistency, but with the undesirable effect of increase its glycemic index and its calories from simple sugars; it is known that consumption of products with these last two characteristics are related to childhood obesity, which is a worldwide growing disease. Stevia rebaudiana is a plant that naturally contains glycosides with high sweetening power and it is considered safe for consumption. Therefore the aim of this work was to develop a gummy candy reduced in calories by replacing sugar with Stevia rebaudiana B., and analyzes its texture and acceptability. Gummy candy were prepared with different percentage of sugar reduction (-20, -40, -60, -80 and -100%) and a product control (100% sugar); gummy elasticity was assess by displacement and maximum deformation, whereas resistance was evaluated by breaking strength; those gummies with better elasticity and resistance parameters underwent proximate analysis and sensory evaluations with a unstructured scale applied to 90 school children aged between 6 and 10 years old. A gummy candy reduced in calories with 60% sugar substitution with S. rebaudiana was developed; the level of satisfaction in school children was statistically the same respect to the gummy made of 100% sugar (p <0.05) (AU)

Validation of HPLC-UV method for determination of minor glycosides contained in Stevia rebaudiana Bertoni leaves.

Leaves of Stevia rebaudiana contain glycosides with sweetness and biological activity. However besides the major glycosides, there are other glycosides within extracts that may contribute to its activity, and therefore it is important to quantify them. In this work, an isocratic HPLC method was validated for determination of dulcoside A, steviolbioside, rebaudioside C and rebaudioside B. An HPLC method was performed using a C18 column (250 × 4.6 mm, particle size 5 µm) and a UV detector set at 210 nm. The mobile phase consisted of a 32:68 (v/v) mixture of acetonitrile and sodium phosphate buffer (10 mmol/L, pH 2.6), set to a flow rate of 1.0 mL/min. The calculated parameters were: sensitivity, linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy and precision. The calibration curves were linear over the working range 25-150 µg/mL, with coefficient of correlation of ≥0.99 and coefficient of determination of ≥0.98. The LOD was 5.68-8.81 µg/mL, while the LOQ was 17.21-26.69 µg/mL. The percentage recoveries of fortified samples were 100 ± 10% and precision, relative standard deviation, was <10%. The method validation showed accuracy, linearity and precision; therefore this method can be applied for quantitative analysis of minor steviol glycosides in S. rebaudiana leaves.

[Safety assessment of stevia rebaudiana bertoni grown in southeastern Mexico as food sweetener]. / Evaluación de la inocuidad de Stevia rebaudiana bertoni cultivada en el sureste de méxico como edulcorante de alimentos.

Stevia rebaudiana leaves and their glycosides have been recently and significantly used so important as sweeteners. However, it has been reported an antihyperglycemic effect of the extract and a glycoside. The aim of this study was to quantify S. rebaudiana glycosides, assess cytotoxicity of the extract and its acute and chronic effect on blood glucose in animal models and in human. The glycosides of the Morita II and Criolla extract were quantified by HPLC, using a C18 column (250 mm x 4.6 mm and particle size of 5 uM) with UV detection at 210 nm, mobile phase of acetonitrile/sodium phosphate buffer 10 mmol/L, pH 2.6 (32:68 v/v). Cytotoxicity study was performed in Vero cells, whereas an intraperitoneal glucose tolerance test (IPGTT) and a chronic consumption assay (4 weeks) were executed in an animal model of diabetes; finally the glycemic index (G.I.) was determined in healthy individuals. The glycoside content is higher in the Morita variety II although both had a CC50 >300 g/mL. The areas under the curve of the IPGTT and fasting glucose of the animals were not significantly different (p> 0.05) and the I.G. extract was 11.11 %, which classifies the extract as low I.G. The extract of S. rebaudiana Morita II has a low glycemic index and, in the doses tested, is not cytotoxic nor has acute or chronic effect on blood sugar, which makes it a safe sweetener.

Las hojas de Stevia rebaudiana y sus glucósidos recientemente se han comenzado a utilizar de manera importante como edulcorantes. Sin embargo, existen reportes acerca del efecto antihiperglucemiante de extractos y un componente glucósido. El objetivo de este trabajo fue cuantificar los glucósidos de S. rebaudiana, evaluar la citotoxicidad y el efecto de la administración aguda y crónica del extracto sobre la glucemia en modelos animales como en humanos. Los glucósidos de los extracto de las variedades Morita II y Criolla se cuantificaron por HPLC, empleando una columna C18 (250 mm x 4.6 mm y tamaño de partícula de 5m), con detector UV a 210 nm, fase móvil de acetonitrilo/amortiguador fosfato de sodio 10 mmol/L, pH 2.6 (32:68 v/v). Se realizó un estudio de citotoxicidad en células Vero, una prueba de tolerancia a la glucosa intraperitoneal y ensayo de consumo crónico (4 semanas) en un modelo animal de diabetes y finalmente, se determinó el índice glicémico (I.G) en individuos sanos. El contenido de glucósidos fue mayor en la variedad Morita II aunque la CC50 en ambas es >300 g/mL. Las áreas bajo la curva de la IPGTT así como la glucosa en ayuno de los animales no fueron significativamente diferentes (p>0.05) y el I.G. del extracto fue 11.11%, lo cual lo clasifica como I.G. bajo. El extracto de S. rebaudiana Morita II es de bajo índice glicémico y, en las dosis evaluadas, no es citotóxico ni posee efecto agudo o crónico sobre la glucemia, lo cual lo hace un edulcorante inocuo.

Evaluación de la inocuidad de Stevia rebaudiana Bertoni cultivada en el sureste de México como edulcorante de alimentos / Safety assessment of Stevia rebaudiana Bertoni grown in Southeastern Mexico as food sweetener

Las hojas de Stevia rebaudiana y sus glucósidos recientemente se han comenzado a utilizar de manera importante como edulcorantes. Sin embargo, existen reportes acerca del efecto antihiperglucemiante de extractos y un componente glucósido. El objetivo de este trabajo fue cuantificar los glucósidos de S. rebaudiana, evaluar la citotoxicidad y el efecto de la administración aguda y crónica del extracto sobre la glucemia en modelos animales como en humanos. Los glucósidos de los extracto de las variedades Morita II y Criolla se cuantificaron por HPLC, empleando una columna C18 (250 mm x 4.6 mm y tamaño de partícula de 5µm), con detector UV a 210 nm, fase móvil de acetonitrilo/amortiguador fosfato de sodio 10 mmol/L, pH 2.6 (32:68 v/v). Se realizó un estudio de citotoxicidad en células Vero, una prueba de tolerancia a la glucosa intraperitoneal y ensayo de consumo crónico (4 semanas) en un modelo animal de diabetes y finalmente, se determinó el índice glicémico (I.G) en individuos sanos. El contenido de glucósidos fue mayor en la variedad Morita II aunque la CC50 en ambas es >300 µg/mL. Las áreas bajo la curva de la IPGTT así como la glucosa en ayuno de los animales no fueron significativamente diferentes (p>0.05) y el I.G. del extracto fue 11.11%, lo cual lo clasifica como I.G. bajo. El extracto de S. rebaudiana Morita II es de bajo índice glicémico y, en las dosis evaluadas, no es citotóxico ni posee efecto agudo o crónico sobre la glucemia, lo cual lo hace un edulcorante inocuo (AU)

Stevia rebaudiana leaves and their glycosides have been recently and significantly used so important as sweeteners. However, it has been reported an antihyperglycemic effect of the extract and a glycoside. The aim of this study was to quantify S. rebaudiana glycosides, assess cytotoxicity of the extract and its acute and chronic effect on blood glucose in animal models and in human. The glycosides of the Morita II and Criolla extract were quantified by HPLC, using a C18 column (250 mm x 4.6 mm and particle size of 5 uM) with UV detection at 210 nm, mobile phase of acetonitrile/sodium phosphate buffer 10 mmol/L, pH 2.6 (32:68 v/v). Cytotoxicity study was performed in Vero cells, whereas an intraperitoneal glucose tolerance test (IPGTT) and a chronic consumption assay (4 weeks) were executed in an animal model of diabetes; finally the glycemic index (G.I.) was determined in healthy individuals. The glycoside content is higher in the Morita variety II although both had a CC50 >300 µg/mL. The areas under the curve of the IPGTT and fasting glucose of the animals were not significantly different (p> 0.05) and the I.G. extract was 11.11 %, which classifies the extract as low I.G. The extract of S. rebaudiana Morita II has a low glycemic index and, in the doses tested, is not cytotoxic nor has acute or chronic effect on blood sugar, which makes it a safe sweetener (AU)

[Development of a gummy candy reduced in calories by sugar substitution with Stevia rebaudiana B]. / Desarrollo de una golosina tipo "gomita" reducida en calorías mediante la sustitución de azúcares con Stevia rebaudiana B.

The consumption of gummy candy is widespread among people of different ages but mainly by children. The formulation of this product requires sugar that contributes to their flavor and consistency, but with the undesirable effect of increase its glycemic index and its calories from simple sugars; it is known that consumption of products with these last two characteristics are related to childhood obesity, which is a worldwide growing disease. Stevia rebaudiana is a plant that naturally contains glycosides with high sweetening power and it is considered safe for consumption. Therefore the aim of this work was to develop a gummy candy reduced in calories by replacing sugar with Stevia rebaudiana B., and analyzes its texture and acceptability. Gummy candy were prepared with different percentage of sugar reduction (-20, -40, -60, -80 and -100%) and a product control (100% sugar); gummy elasticity was assess by displacement and maximum deformation, whereas resistance was evaluated by breaking strength; those gummies with better elasticity and resistance parameters underwent proximate analysis and sensory evaluations with a unstructured scale applied to 90 school children aged between 6 and 10 years old. A gummy candy reduced in calories with 60% sugar substitution with S. rebaudiana was developed; the level of satisfaction in school children was statistically the same respect to the gummy made of 100% sugar (p <0.05).

Las gomitas son golosinas de consumo difundido entre personas de diferentes edades aunque principalmente por los niños. La formulación de este producto requiere azúcar que contribuye a su sabor y consistencia, aunque con el efecto indeseable de incrementar su índice glicémico y calorías provenientes de azúcares simples; se sabe que el consumo de productos con estas dos últimas características están relacionados con la obesidad infantil, la cual es una enfermedad en crecimiento a nivel mundial. La Stevia rebaudiana es una planta que naturalmente contiene glucósidos con alto poder endulzante y que se considera segura para su consumo. El objetivo de este trabajo fue desarrollar una golosina tipo "gomita" reducida en calorías mediante la sustitución de azúcares con Stevia rebaudiana B. y analizar su textura y grado de aceptación. Se elaboraron gomitas con diferente porcentaje de reducción de azúcar (-20, -40, -60, -80 y -100%) y un producto control (100% azúcar), a las cuales se evaluó su desplazamiento y deformación máxima para evaluar la elasticidad, así como la fuerza de ruptura para determinar la resistencia; aquellas gomitas con mejores parámetros de elasticidad y resistencia se les realizaron el análisis proximal y el análisis sensorial con una escala no estructurada aplicada a 90 niños escolares con edades comprendidas entre 6 y 10 años. Se desarrolló una golosina tipo "gomita" reducida en calorías con un porcentaje de sustitución de azúcar de hasta 60% con S. rebaudiana, cuyo nivel de agrado en niños escolares fue estadísticamente igual comparado con la gomita realizada con 100% de azúcar (p.

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.

Matrix solid-phase dispersion extraction of organophosphorus pesticides from propolis extracts and recovery evaluation by GC/MS.

Five organophosphorus pesticides (dichlorvos, diazinon, malathion, methyl parathion and coumaphos) were extracted from propolis by matrix solid-phase dispersion (MSPD) extraction using octadecylsilica (C18, 1.0 g) as dispersant material. The kind of solvent elution (acetonitrile or ethyl acetate), volume (8 mL and 15 mL), and adsorbent used to clean-up the extracts (graphitized carbon, florisil™ and silica) were optimized using fortified propolis samples (5.0 µg g(-1)). Recovery was determined by gas chromatography with mass spectrometric detection in selected ion monitoring mode (GC/MS-SIM) and statistical analysis was done to determine better extraction conditions. Relatively high recovery and lower relative standard deviation values (3.1-14.6%) were obtained when analytes were eluted with ethyl acetate from the MSPD column. Diazinon, malathion, methyl parathion, and coumaphos show recoveries of 72.7%, 84.6%, 62.6%, and 78.3%, respectively. In contrast, the recovery for dichlorvos was 53.8%. Additional adsorbents tested for clean-up and increase in solvent elution did not affect recoveries positively and caused a high background in chromatograms. Thus, final conditions were 1 mL of sample, 1 g C18 and 8 mL of ethyl acetate.