OPTIMIZATION OF THE EXTRACTION PROCESS FOR Aganonerion polymorphum Pierre ex Spire LEAF EXTRACT USING THE BOX-BEHNKEN DESIGN

Abstract

This study aimed to optimize the extraction process of total polyphenols (TPC) and total flavonoids (TFC) from Aganonerion polymorphum Pierre ex Spire leaves. The experiment was designed using response surface methodology (RSM) based on a Box–Behnken design (BBD), with three independent variables: ethanol concentration (50 - 90%), solvent-to-sample ratio (10: 1 - 20: 1, mL/g) and ultrasonic time (5 - 15 min). The response variables were TPC (mg GAE/g DW) and TFC (mg QE/g DW). The developed models showed high statistical significance (Pmodel < 0.0001), with non-significant lack of fit (PTPC = 0.069; PTFC = 0.219) and high coefficients of determination (R² > 98% for both models), confirming their reliability and stability. Linear, quadratic, and interaction effects significantly influenced extraction efficiency, indicating nonlinearity and the presence of maxima within the studied range. The optimal extraction conditions were determined as 73% ethanol, solvent-to-sample ratio of 16: 1 (mL/g) and ultrasonic time of 10.5 min. Experimental validation using two-tailed tests (μ ≠ μ₀) confirmed the accuracy of the predicted models. These findings provide robust scientific evidence for developing an efficient process to produce extracts enriched with bioactive compounds.