Characterization of non-polar and polar bioactive compounds obtained by pressurized biobased solvents from different Arctium lappa L. root ecotypes

This study introduces a novel pressurized liquid extraction (PLE) strategy utilizing biobased solvents to simultaneously extract non-polar and polar compounds with antioxidant and anticholinergic properties from burdock roots. The influence of altitude and weeding on the bioactive composition of three burdock root ecotypes was evaluated: two from 150 m (one subjected to weeding during growth and another not subjected to weeding) and one from 800 m without weeding. A simplex-centroid mixture design identified 100% 2-methyltetrahydrofuran as the optimal solvent for PLE, offering superior extraction of bioactive compounds due to its ability to form strong hydrogen bonds with phenolic groups. Extraction at 100 °C was found to be optimal, avoiding the low yields and undesirable reactions observed at 40 °C and 160 °C, respectively. Altitude emerged as the most significant factor influencing bioactivity and composition, with roots from 800 m exhibiting the highest bioactivity. Key bioactive compounds included caffeoylquinic acids, caryophyllene oxide, spathulenol, and bisnorallocholanic acid. At 150 m, weeding reduced anticholinergic capacity but increased antioxidant synthesis, though the levels were lower than those observed at higher altitudes. These findings highlight that burdock roots grown at high altitudes without weeding produce extracts rich in antioxidant and neuroprotective compounds, offering significant potential for functional ingredient development.