Controlled Extraction of Flavonoids From Radix Scutellariae by Subcritical Water

Abstract

The extraction of baicalin, wogonoside, baicalein, and wogonin from Radix Scutellariae was performed using subcritical water and conventional extraction. Compared with ethanol extraction, subcritical water extraction required shorter extraction time, yielded a higher efficiency, and required less extraction solvent. The stability of four flavonoids under subcritical water conditions was investigated, and the extraction products can be controlled through adjusting the properties of subcritical water, namely the selective extraction of some important components. The effects of key operation conditions including extraction temperature (110 to −160 °C), extraction time (10–90 min), water loadings (2.0–4.5 mL), and particle sizes (>20 to <100 mesh) were evaluated. The highest extraction yields of baicalin and wogonoside were obtained at extraction temperature of 12 °C, extraction time of 60 min, water loadings of 4 mL, and 60–100 mesh. The highest extraction yields of baicalein and wogonin were obtained at extraction temperature of 16 °C, extraction time of 20 min, water loadings of 4 mL, and 60–100 mesh.

Enhanced Extraction of Bioactive Components of 3,29–Dibenzoylkarounidiol and Polysaccharides from Semen richonsanthis Using Subcritical Water Technology

“…It has been reported that subcritical water has a strong dissolving capacity for weakly polar compounds, including polycyclic aromatic hydrocarbons, fatty acids and biomasses . For example, subcritical water has been successfully applied to the extraction of phenols, flavonoids, alkaloids, essential oils, triterpenes, saccharides, organic acids and anthraquinones . With an increasing focus on green chemistry and natural drugs, subcritical water has gradually combined with other green additions, such as ethanol, ionic liquids, surfactants, carbon dioxide and enzymes .…”