METHOD FOR QUANTIFYING THE AMOUNT OF PHENYLPROPANOIDS IN STEVIA RAW MATERIALS

Abstract

Dried stevia leaves (Stevia rebaudiana Bertoni) were used as objects of research. Four samples of stevia raw materials of different origin were studied: No. 1 (Russia, Penza region), No. 2 (Russia, Republic of Crimea), No. 3 (Paraguay), No. 4 (India). The purpose of this work is to develop a method for quantifying the amount of phenylpropanoids in stevia leaves. Quantitative determination of the amount of phenylpropanoids in stevia leaves by direct spectrophotometry was carried out. Thin-layer chromatography was used to confirm the presence of phenylpropanoids in stevia leaves. The presence of phenylpropanoids in stevia leaf extracts was confirmed by direct spectrophotometry, the analytical maxima of the compounds studied were determined – 290 and 330 nm. The optimal conditions of extraction of phenylpropanoids from raw materials of this plant (extractant – ethyl alcohol 70%; ratio "raw material–extractant" – 1 : 100; extraction time – 45 min; the degree of grinding of raw materials – 1.0 mm). It was determined that the error of a single determination of the content of phenylpropanoids in stevia leaves with a confidence probability of 95% is ±0.44%. It was found that the content of phenylpropanoids in stevia varies in the range of 6.73–10.51%.