Optimization of ultrasonic-assisted extraction of flavonoid from Portulaca oleracea L. by response surface methodology and chemical composition analysis

Abstract

Optimization of ultrasonic extraction of Portulaca oleracea L. flavonoids (POF) was investigated using single-factor experimentation combined with response surface methodology. The optimal conditions for the highest yield (16.25 mg RE/g DW) of POF was 39.01% ethanol, 55.25°C extraction temperature, 15 min extraction time, and 23.92 (v/m) liquid-to-solid ratio. The crude extract of POF was purified on the polyamide resin. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, a yellow tetrazole assays of the flavonoids were evaluated, which suggested the concentrations of the flavonoids (0–1 mg/mL) and quercetin (0–1 mg/mL). Quercetin was identified in the extract by comparing relative retention time of the reference standard.