Box-Behnken design optimization and kinetics of phenolics extraction from Etlingera elatior leaves

To date, none has reported on the Etlingera elatior leaves extract obtained by the ultrasonic-assisted extraction (UAE) technique. Therefore, the UAE parameters were investigated in this study, and the extraction method was optimized using the Box-Behnken design. The optimal condition was the extraction conducted for 16 min, at 55 °C, with a ratio of liquid to solid, 38 mL g−1 using methanol as solvent. Patricelli model showed the best fitting result with R2>0.99. The extract exhibited high total phenolic content (228.35±17.34 mg GAE g−1), DPPH antioxidant activity (IC50 value 66.25±7.77 µg mL−1), and antibacterial activity towards Bacillus subtilis. This study demonstrated that the UAE methodology could efficiently extract phenolics from E. elatior leaves.