Antioxidant Capacity and Total Phenolic and Flavonoid Contents of Methanolic Extracts of Urtica dioica L. by Different Extraction Techniques

In this study, the efficacy of different extraction techniques (maceration, ultrasound-assisted and Soxhlet extraction) on the content of biologically active components in extracts from fresh and dried nettle leaves, and their antioxidant activity were analyzed. Methanol was used as the solvent. Total phenolic content and antioxidant capacity were determined by Folin-Ciocalteu, DPPH and FRAP methods, respectively. High content of total phenolic compounds and high antioxidant activity were recorded in extracts of dried nettle. Extracts obtained from fresh nettle samples showed significantly lower content of analyzed bioactive components and lower antioxidant activity. In the case of all extracts, Soxhlet extraction proved to be the most efficient, and maceration the least efficient extraction technique for isolation of bioactive components from nettle leaves.