Inulin, phenolic content and antioxidant potential of burdock (Artium lappa L.) roots extracts obtained by green extraction mrthods

Burdock (Arctium lappa L.) roots are traditionally used in folk medicine as diuretic and curing rheumatism, gastritis, gout, throat pain, arthritis and rashes. These pharmacological properties are due to many bioactive compounds such as flavonoids and fructooligosaccharides. Nowadays the the application of green methods for extraction of natural compounds gains more and more attention. The object of the current research was to determine inulin and sugars content, phenolic content and antioxidant potential in 70% ethanol and water extracts obtained by two “green“ extraction methods, namely pressure-liquid extraction and ultrasound-assisted techniques. The content of total fructans, as well as inulin and sugars were analyzed by resorcinol-thiourea and high-performance liquid chromatography with refractive index detection. Total phenols and flavonoids were determined by Folin-Chiocalteu and Al(NO3)3 reagents. Antioxidant activity was evaluated by four reliable methods (DPPH, ABTS, FRAP and CUPRAC). The established inulin content varied from 0.27 to 4.0 g/100 g dw in prevalence of the ultrasound-assisted extract obtained with water. Additionally, the established phenolic compounds content (from 10.35 to 18.16 mg GAE/g dw) and antioxidant activities demonstrated the budrock roots as potential source with beneficial properties