Impacts of microwave-assisted extraction parameters on total phenolic compounds yield from Algerian Moringa oleifera leaves, using response surface methodology

The study aimed to optimise the microwave-assisted extraction (MAE) of total phenolic compounds (TPC) from Moringa oleifera Lam. leaves using response surface methodology (RSM) and Box-Behnken designs (BBD). Factors such as ethanol concentration, microwave power, irradiation time, and solvent to solid ratio were assessed in single-factor tests. Under optimal extraction conditions (48.86% ethanol, 626.53 W microwave power, 99.48 s irradiation, 29.67 mL/g solvent to solid ratio and 21.12 W/mL power density), TPC was 58.45 ± 0.68 mg GAE/g DW, close to the predicted 59.78 ± 1.47 mg GAE/g DW. The MAE method outperformed maceration extraction (8.41 ± 0.25 mg GAE/g DW) and decoction extraction (38.74 ± 0.81 mg GAE/g DW) in terms of extraction time, solvent use, and efficiency. The optimised extract exhibited significant antioxidant activity with IC50 values of 0.294 ± 0.004 mg/mL (DPPH) and 0.425 ± 0.005 mg/mL (ABTS), confirming the efficacy of MAE in preparing antioxidant-rich plant extracts.