Optimization of Energized Dispersive Guided extraction (EDGE) of antioxidants from Eugenia uniflora L. (Pitanga) leaves using response surface methodology

Abstract

Leaf extracts of Eugenia uniflora L. (Pitanga) been used in traditional medicine to treat digestive disorders or hypertension and have anti-inflammatory and antioxidant activities. The antioxidant compounds are substances able to inhibit molecular oxidation in nature or in manufactured products. The optimization of antioxidant extraction conditions from E. uniflora leaves by Energized Dispersive Guided Extraction (EDGE®) was achieved by response surface methodology. The univariate methodologies and central composite rotatable design were employed for optimization of extraction parameters (solvent type, extraction time, temperature and number of cycles) in terms of antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity assay (IC50). The optimum operating conditions for extraction were acetone, one cycle of extraction, 125 sec extraction time, 91 °C temperature, and 40 mL g−1 solvent-to-mass ratio. Under these conditions, the obtained extract exhibited significant antioxidant properties with lower IC50 of scavenging activity on DPPH free radical and 1346.95 ± 76.40 μmol TE g−1 on ORAC assay. GC–MS analysis of the extract showed important bioactive compounds, such as vitamin E, germacrone, spathulenol, among others. The EDGE® proved to be a fully automated technique for recovery of antioxidant compounds offering several advantages, such as reduced solvent and time consumption, and reproducibility.