A green method of extracting and recovering flavonoids from Acanthopanax senticosus using deep eutectic solvents

In recent years, green extraction of bioactive compounds from herbal
medicines has generated widespread interest. Deep eutectic solvents (DES)
have widely replaced traditional organic solvents in the extraction
process. In this study, the efficiencies of eight tailor-made DESs in
extracting flavonoids from Acanthopanax senticosus (AS) were compared.
Response surface methodology (RSM) was employed to optimize the
influencing parameters including ultrasonic power, HBA-HBD ratio, water
content, solid-liquid ratio, extraction temperature and extraction time.
DES composed of glycerol and levulinic acid at a 1:1 ratio was established
as the most suitable extraction medium. Optimal conditions were ultrasonic
power of 500W, water content of 28%, solid-liquid ratio of 1:18 g·mL-1,
extraction temperature of 55℃ and extraction time of 73 minutes. The
extraction yield of AS total flavonoids reached 23.928±0.071 mg·g-1, which
was 86.3% and 43.8% higher compared with traditional solvent soak and
ethanol reflux extraction methods, respectively. Macroporous resin (D-101,
HPD-600, S-8 and AB-8) was used to recover flavonoids from extracts. The
AB-8 resin showed higher adsorption/desorption performance, with a
recovery rate of total flavonoids of up to 71.56±0.256%. In addition, DES
solvent could be efficiently recovered through this process and reused. In
summary, ultrasonic-assisted DES combined with the macroporous resin
enrichment method is exceptionally effective in extracting flavonoids from
AS and provides a promising environmentally friendly and recyclable
strategy for flavonoid extraction from natural plant sources.