Optimization of phenolics recovery from strychnos nux-vomica L. seed applying deep eutectic solvent-ultrasound assisted extraction

Strychnos nux-vomica L. seeds (SNV) are a rich source of bioactive compounds with antioxidant and antidiabetic properties. In this study, the deep eutectic solvent-ultrasound assisted extraction (DES-UAE) is applied for the extraction of bioactive compounds from SNV seeds, which significantly enhances extraction efficiency, while reducing environmental impact. DES made up of ammonium acetate-propanoic acid (1:3) in combination with ethanol and UAE offered higher recovery rates of SNV bioactive. The extraction process was optimized using response surface methodology (RSM) along with artificial neural networking (ANN), considering extraction time (X1), temperature (X2), and DES/feed ratio (X3) as the independent variables. The dependent variables (responses) evaluated were extraction yield, the total phenolic and flavonoid (TP and TF) content, antioxidant capacity (AC), and antidiabetic (AD) potential. Optimal extraction conditions (25 min, 40 °C temperature, 30 mL/g DES/feed ratio) at 40 kHz ultrasound frequency resulted in 6.31% yield, 64.72 (mg GAE/g) dw TP, 103.19 mg (QE/g) dw TF, 89.87% AC, and 68.53% antidiabetic (AD) potential. The model’s reliability was confirmed through smaller (≤ 5%) relative standard deviation (RSD), root mean square error (RMSE), percentage prediction error (PPE), absolute average deviation (AAD), and R² values. Scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX) analysis showed effective cell disruption, supporting enhanced extraction. The outcomes of the present research recommend that DES-based solvent in combination with UAE can be further explored for sustainable and efficient extraction of phenolic bioactives.