Caules de Stevia rebaudiana como fonte de obtenção de um extrato com alto teor antioxidante

Abstract

Stevia has been used since ancient times for various purposes around the world. For centuries, the Guarani tribes of Paraguay and Brazil have used stevia species as a sweetener in yerba mate and medicinal teas for the treatment of heartburn and other diseases as there is a heterogeneous mixture of compounds already identified in the plant composition. These compounds, in addition to sweetness, may also offer therapeutic benefits as they have antihyperglycemic, antihypertensive, antiinflammatory, anti-tumor, antidiarrheal, diuretic and immunomodulatory effects. Although stevia stem has a lower steviol glycoside content when compared to leaves, it can be a source of antioxidant and antimicrobial phytochemicals. Thus this study sought to analyze the antioxidant capacity, phenolic compounds and flavonoids present in the stevia stem hydroalcolic extract in an extract obtained through experimental design composed at the central point (3²) varying solvent concentration (ethanol: water) material content using as a response variable the mass extraction yield and the percentage of antioxidant activity. It was observed through the planning and treatment of the data that the higher the water concentration in the solvent, the better the mass extraction yield, however, the opposite applies to the antioxidant content, which had its maximum in the ethanol: water ratio. (90:10) and 1: 5 w / v relative to plant material. Thus, the extract obtained with data optimization showed 76.52% inhibition of antioxidant activity; 4.65 mgEAG / mL phenolic compounds and 1.33 mgEQ / mL flavonoids.