Optimization of Ultrasonic Extraction of Phenolic Compounds from Epimedium brevicornum Maxim Using Response Surface Methodology and Evaluation of Its Antioxidant Activities In Vitro

The ultrasound-assisted extraction of phenolic compounds from Epimedium brevicornu Maxim was modeled using response surface methodology. A Central Composite Design (CCD) was employed to optimize three extraction variables, including ethanol concentration (X (1)), extraction time (X (2)), and ratio of aqueous ethanol to raw material (X (3)), for the achievement of high extraction yield of the phenolic compounds. The optimized conditions are X (1) of 50% (v/v), X (2) of 27.5 min, and X (3) of 250 mL/g. Under these conditions, the experimental yield is 4.29 ± 0.033% (n = 3). The antioxidant activity was evaluated using the DPPH assay and ferric-reducing antioxidant power (FRAP). And it indicates that the phenolic compounds from Epimedium brevicornu Maxim possess significant antioxidant activity. HPLC analysis reveals that the main phenolic compound in the extract product was identified as gallic acid, catechin (Cianidanol), p-hydroxybenzoic acid, vanillic acid, caffeic acid, ferulaic acid, rutin, benzoic acid, and quercetin.