Optimization of the subcritical water extraction of sulfated flavonoids from Flaveria bidentis

Abstract

Flaveria bidentis, an invasive plant, contains sulfated flavonoids (SFs) with therapeutic potential; therefore, their extraction would add value to the plant residues generated during its weeding. This work reports the optimized obtaining of these SFs, by means of subcritical water extraction (SWE). The combined effects of Flow rate, Temperature, and Particle size were investigated via response surface methodology involving the Doehlert experimental design. The optimal extraction conditions were: leaves: Flow rate = 2.86 mL/min, Temperature = 101.2 °C and Particle size = 420–< 1190 µm; flowers: Flow rate = 4.29 mL/min, Temperature = 147.7 °C and Particle size = 0 - < 420 µm. Under these conditions, 39.43 and 7.5 mg of totals SF/100 g of leaves and flowers were recovered, respectively. Likewise, we could demonstrate that SWE showed an improved efficiency the extraction of the SFs under study of more than twice as high compared to the conventional method (reflux).