Extraction of antioxidant components from hayit (Vitex agnus castus L.) plant with deep eutectic solvents

This study aimed to efficiently extract antioxidant compounds from the leaves, flowers, and seeds of Vitex agnus-castus L., and to comparatively evaluate two extraction methods: microwave-assisted extraction (MAE) and ultrasound-assisted extraction (UAE).The extraction processes were conducted using five different deep eutectic solvents (DESs) and two conventional organic solvents. The obtained extracts were analyzed for their total antioxidant capacity (TAC) using CUPRAC, ABTS, and DPPH methods. A Box-Behnken experimental design model was employed to optimize the extraction conditions, and model fit along with parameter effects were evaluated through ANOVA and 3D surface response plots. According to the results, the MAE method proved to be more efficient than UAE, showing a higher model fit (R² = 0.9955) and predictive power (R²t = 0.9274). Among all plant parts, leaf extracts exhibited the highest antioxidant activity in all assays, with the MAE-DES combination yielding a notably high CUPRAC value of 0.5297 mmol TR/g. In seed extracts, the UAE-DES combination achieved a remarkable DPPH value of 0.3859 mmol TR/g. Among the analytical methods used, the CUPRAC assay provided more comprehensive results overall, due to its wide sensitivity and stability toward both hydrophilic and lipophilic compounds. The findings indicate that both the extraction method and solvent selection play a critical role in antioxidant recovery. Moreover, DESs offer a green, efficient alternative to traditional solvents. This study contributes to the sustainable extraction of antioxidant compounds from Vitex agnus-castus in line with the principles of green chemistry.