Atividade antimicrobiana de Stevia rebaudiana Bertoni e de adoçantes não calóricos sobre bactérias cariogênicas: estudo in vitro / Antimicrobial activity of Stevia rebaudiana Bertoni and non-caloric sweeteners on cariogenic bacteria: in vitro study

Objetivo: avaliar a atividade antimicrobiana in vitro da planta Stevia rebaudiana Bertoni e de adoçantes não calóricos sobre o crescimento de Streptococcus mutanse Lactobacillus casei, micro-organismos cariogênicos presentes na cavidade bucal. Materiais e método: o estudo foi realizado utilizando as cepas padrões de S.mutans (UA159) e L. casei (ATCC7469). Foram avaliados diferentes compostos não calóricos substitutos dasacarose nas concentrações de 1%, 5% e 10%: eritritol(ER), Fit Sucralose® (SU), Stevita® (ST), solução de Steviarebaudiana Bertoni (SSr) e, como controle positivo,digluconato de clorexidina (DC). A análise do efeito inibitório desses compostos no crescimento das bactériasfoi feita por meio da técnica de difusão em ágar. Resultado:observou-se que existe um efeito inibitório decrescimento de ambos os micro-organismos por parte da SSr e do ER, enquanto os demais adoçantes testa dosnão tiveram efeito inibitório sobre esses micro-organismos.Conclusão: os resultados demonstram que SSR eER apresentam efeito inibidor no crescimento das cepastestadas de S. mutans e L. casei. (AU)

Objective: The study evaluated the in vitro antimicrobial activity of the Stevia rebaudiana Bertoni plant and non-caloric sweeteners on the growth of Streptococcus mutans and Lactobacillus casei, which are cariogenic microorganisms present in the oral cavity. Materials and method: The study was conducted using the standard strains of S. mutans (UA159) and L. casei (ATCC7469). Different non-caloric compounds were evaluated at concentrations of 1%, 5%, and 10%: erythritol (ER), Fit Sucralose™ (SU), Stevita™ (ST), Stevia rebaudiana Bertoni solution (SSr), and chlorhexidine digluconate (CD) as positive control. The inhibitory effect of these compounds on the growth of bacteria were analyzed by the agar diffusion technique. Result: There was a growth inhibition effect for both microorganisms by SSr and ER, whereas the other sweeteners tested had no inhibitory effect on the microorganisms. Conclusion: The results showed that SSr and ER present an inhibitory effect on the growth the strains tested of S. mutans and L. casei. (AU)

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.

Anticariogenic properties and effects on periodontal structures of Stevia rebaudiana Bertoni: narrative review / Propiedades anticariogénicas y efectos a nivel periodontal de Stevia rebaudiana Bertoni: revisión narrativa

Introduction: Stevia rebaudiana Bertoni is a natural non-caloric sweetener, withmore sweetness than sucrose, without adverse effects, which has demonstrated to have multiples benefits to the systemic health and recently to the oral health. This review’s objective is to describe anti-cariogenic and anti-periodontophatics properties of its extracts. Results: Stevioside and rebaudioside A are the most important glycosides of the Stevia and none is cariogenic. In vitro researches have shown that Stevia extracts have anti-bacterial activity on Streptococcus mutans, Streptococcus sobrinus and Lactobacillus acidophilus, organisms that are closely related to the production and development of tooth decay. In vivo and in vitro it has been observed that the production of bacterial acids decrease attributing it a low acidogenic potential and a lesser effect of the demineralization of the enamel in comparison with others sweeteners. Furthermore, in vivo it has been proved an anti-plaque effect mainly due to a decrease in the production of bacterial insoluble polymers. These characteristics in combination with antiinflammatory properties could result potentially effective in the treatment of periodontal diseases in significant numbers, as it has been observed in studies conducted in animals. Conclusion: Stevia presents properties that potentially are anti-caries and anti periodontal diseases. However, in vivo studies are necessary to confirm these assumptions and provide a greater understanding of the mechanisms of action of this plant and the components involved. Notwithstanding, with the existing background, this sweetener can be postulated as a potential therapeutic complement in the odontological care, especially in patients that present base conditions such as obesity, diabetes and high blood pressure.

Introducción: Stevia rebaudiana bertoni es un edulcorante natural no calórico, con mayor dulzor que la sacarosa, sin efectos adversos, que ha demostrado tener múltiples beneficiosos para la salud sistémica y recientemente para la salud oral. El objetivo de esta revisión es describir propiedades anticariogénicas y antiperiodontopáticas de sus extractos. Resultados: Esteviósido y rebaudiósido A son los glicósidos más importantes de Stevia y ninguno es cariogénico. Estudios in vitro han demostrado que extractos de Stevia presentan actividad antibacteriana sobre Streptococcus mutans, Streptococcus sobrinus y Lactobacillus acidophillus, organismos estrechamente relacionados en la producción y desarrollo de caries. In vivo e in vitro se ha observado que disminuye la producción de ácidos bacterianos atribuyéndosele un bajo potencial acidogénico y un menor efecto de desmineralización del esmalte en comparación con otros edulcorantes. Además, in vivo se ha comprobado un efecto antiplaca principalmente debido a una disminución en la producción de polímeros insolubles bacterianos. Estas características, más sus propiedades antiinflamatorias y cicatrizantes, podrían resultar potencialmente efectivas en el tratamiento de enfermedades periodontales en cifras significativas, como se ha observado en estudios desarrollados en animales. Conclusión: Stevia presenta propiedades potencialmente anti-caries y anti-enfermedades periodontales. Sin embargo, son necesarios estudios in vivo que confirmen estos postulados y proporcionen una mayor comprensión de sus mecanismos de acción y de los componentes que intervienen. No obstante, con los antecedentes existentes, se puede postular a este edulcorante como un potencial complemento terapéutico en la atención odontológica, sobre todo en pacientes que presentan condiciones de base como obesidad, diabetes e hipertensión.

Steviol effect, a glycoside of Stevia rebaudiana, on glucose clearances in rats / O efeito do esteviol, um glicosídeo da Stevia rebaudiana, no clearance da glicose em ratos

Stevia rebaudiana, a South American plant normally used as a natural herbal sweetener, has been suggested as exerting beneficial effects on human health, including as an antihypertensive and antihyperglycemic. The present experiment was undertaken to evaluate the renal excretion of steviol, the aglycone of several natural products extracted from the leaves of S. rebaudiana, and to clarify the actual participation of this compound on the renal excretion of glucose in rats, which has been previously suggested as the preferential action of steviol on the Na+-glucose renal tubular transport system. Steviol was obtained by enzymatic hydrolysis of stevioside with pectinase. Thirty normal male Wistar rats weighing 345 g were used. After a control period, steviol was infused iv at three doses (0.5, 1.0 and 3.0 mg.kg-1/h), according to classical clearance techniques. During all the experiments no significant changes in inulin clearance (Cin) and p-aminohipuric acid clearance (C PAH) were observed. Administration of steviol resulted in a statistically significant increase in the fractional sodium excretion (FeNa+), fractional potassium excretion (FeK+), urinary flow as percent of glomerular filtration rate (V/GFR) and glucose clearance (C G) when compared to controls, but these effects were absent with the dose of 0.5 mg.kg-1/h. The steviol clearance (C S) was higher than the Cin and lower than the C PAH at all the doses employed in this study. The data suggest that steviol is secreted by renal tubular epithelium, causing diuresis, natriuresis, kaliuresis and a fall in renal tubular reabsorption of glucose.

Stevia rebaudiana, uma planta da América do Sul usada como adoçante natural, parece exercer efeitos benéficos para a saúde humana, incluindo ação anti-hipertensiva e anti-hiperglicêmica. No presente trabalho objetivamos avaliar a excreção renal do esteviol, uma aglicona extraída das folhas de S. rebaudiana, e elucidar a participação deste composto na excreção renal de glicose em ratos, o qual foi sugerido agir no sistema de transporte tubular renal Na+-glicose. O esteviol foi obtido por hidrólise enzimática com pectinase. Foram usados 30 ratos Wistar machos e pesando 345 g. Após um período controle, o esteviol foi infundido iv em três doses (0,5, 1,0 e 3,0 mg.kg-1/h) de acordo com técnicas clássicas de clearance. Durante os experimentos não houve alterações significantes no clearance da inulina (Cin) e do ácido-aminohipúrico (C PAH). A administração de esteviol resultou em um aumento estatisticamente significante na excreção fracional de sódio (FeNa+) e potássio (FeK+ ), no fluxo urinário como porcentagem da taxa de filtração glomerular (V/GFR) e do clearance de glicose (C G) quando comparados aos animais controles, embora estes efeitos estivessem ausentes na dose de 0,5 mg.kg-1/h. O clearance de esteviol (C S) foi maior que o Cin e menor que o C PAH em todas as doses usadas nos experimentos. Os dados sugerem a secreção de esteviol pelo epitélio tubular renal, causando diurese, natriurese, caliurese e uma redução na reabsorção tubular renal de excreção de glicose.