Comparison of the Chemical Composition of Extracts from Scutellaria lateriflora Using Accelerated Solvent Extraction and Supercritical Fluid Extraction versus Standard Hot Water or 70% Ethanol Extraction

The aqueous extract of American skullcap (Scutellaria lateriflora L. (S. lateriflora), Lamiaceae) has been traditionally used by North American Indians as a nerve tonic and for its sedative and diuretic properties. Recent reports stated that flavonoids and possibly amino acids are responsible for the anxiolytic activity. As a part of our search for environmentally friendly solvents to extract the active components from medicinal plants, we used S. lateriflora in a comparison of accelerated solvent extraction (ASE) using water, and supercritical fluid extraction (SFE) using CO2 and 10% EtOH as modifier, at different temperatures. Flavonoids and amino acids were quantified by HPLC−UV and HPLC−MS, respectively. The flavonoid content was compared with conventional extraction methods (hot water extraction and 70% ethanol). The use of ASE at 85 °C with water as solvent gave the best results for flavonoid glycosides and amino acids, whereas SFE gave higher yields of flavonoid aglycones. However, the results obta...