Didžiosios dilgėlės (Urtica dioica L.) fenolinių junginių ekstrakcija

Abstract

The research was carried out in 2020 at Vytautas Magnus University Agriculture Academy, Open Access Joint Research Center for Agriculture and Forestry, in the Laboratory of Raw Plant Materials Quality. The aim of the research is to determinate the influence of solvents of different polarity on the content of phenolic compounds in leaves and root extracts of stinging nettle (Urtica dioica L.). To evaluate the extraction efficiency of solvents of different polarity, the extracts were prepared using the maceration method. Briefly, 5 g of dried nettle leaves and roots were weighed into individual dark glass vials and poured with 150 mL of solvent. To prepare the extracts was using water and different concentrations of ethanol (50, 70, 96%) and methanol (50, 70, 96%). Maceration was performed in sealed dark glass vials at 4°C in the dark for 72 hours. The total phenolic content, in the extracts of nettle leaves and roots, was determined spectrophotometrically according to the Folin–Ciocalteu method (using gallic acid as a standard). Total flavonoids in the extracts of nettle leaves and roots were determined according to the aluminium chloride colorimetric method using quercetin as a standard. The data was evaluated by the method of variance analysis (ANOVA) by the programme STATISTICA. The studies revealed high levels of flavonoids and phenolic compounds in the leaves extract with 96% methanol. The study showed that nettle leaves contain on average 5.2 times more phenolic compounds than roots. In the roots, extraction of phenolic compounds was most efficient using 50% methanol, the significant maximum content of flavonoids was determined using 50% ethanol as a solvent.