Ionic Liquid–Ultrasound-Based Extraction of Biflavonoids from Selaginella helvetica and Investigation of Their Antioxidant Activity

Abstract

As a new and green solvent, ionic liquids (ILs) have received more attention during the green extraction and separation process for natural medicines. In this paper, IL-ultrasound-assisted extraction (IL-UAE) of total biflavonoids (TBFs) from Selaginella helvetica was firstly developed, and different ILs were employed and compared. Based on single-factor experiment, solid–liquid ratio (1:10–1:14 g/mL), IL concentration (0.6–1.0 mmol/mL), and extract temperature (40–60 °C) were further explored, according to response surface methodology (RSM), with TBF yields as the index. Moreover, antioxidant activity of TBF extract was analyzed by four methods, i.e., 2,2-di(4-tert-octylphenyl)-1-picrylhydrazyl (DPPH) and 2,2′-azinobis-(3-ethylbenzth-iazoline-6-sulphonate (ABTS) free radical scavenging assay, ferric ion reducing power assay, and chelation of ferrous ions assay. The results indicated that [C6mim]PF6 had a high selectivity and efficiency. Moreover, important parameters for the extraction process were investigated and optimized. Through parameter optimization (0.8 mmol/L, 250 W, 40 min, 1:12.7 g/mL, and 47 °C), a yield of 18.69 mg/g biflavonoids was obtained from the extract of S. helvetica. Compared with ethanol-UAE, heat-reflux extraction, Soxhlet extraction, and percolation extraction, IL-UAE could not only obtain higher yield in a shorter time, but also reduce the solvent consumption. In addition, TBF extract showed potential antioxidant activity based on the above four antioxidant methods. In short, IL-UAE was first employed to develop a novel and green extraction method for TBF content, and this experiment provides valuable references for further utilization of S. helvetica.

Extraction of Alkaloids from Coptidis Rhizoma via Betaine‐Based Deep Eutectic Solvents

“…To obtain their target compounds, Kou et al., Ji et al . and Jiang et al . performed ultrasonic extraction on ginger, Glycyrrhiza uralensis and Selaginella Helvetica, respectively.…”

Environmentally Friendly Methods for Flavonoid Extraction from Plant Material: Impact of Their Operating Conditions on Yield and Antioxidant Properties

“…In this way, NPCE has been improved by combining with microwave and ultrasound-assisted extractions. For instance, the synergistic operation of NPCE and ultrasound (U-NPCE) helped to increase the extraction yield of total flavonoids due to higher rupture of cell wall [ 69 , 149 ]. These combinations of techniques with NPCE are being researched to improve extraction yield and to optimize parameters in order to scale up processes with industrial applications.…”

Comparison of Chemical Composition and Biological Activities of Eight Selaginella Species

“…Chemical investigation of Selaginella has resulted in the identification of various new compounds such as flavonoids [ 19 , 20 ], lignans [ 21 , 22 ], alkaloids [ 23 ], and terpenoids [ 24 ], which have exhibited a wide range of biological activities, including antioxidant [ 25 , 26 ], antidiabetic [ 2 ], anticancer [ 24 , 27 ], and antimicrobial [ 28 , 29 ] effects. A group of unique compounds named selaginellins, which possess a p -quinone methide and alkynylphenol functional groups, have also been identified from various species of Selaginella [ 30 ].…”