Solvent dielectric constant as a predictor of polyphenol yield and antioxidant activity in extracts from moringa

Polyphenol extraction is strongly influenced by solvent characteristics. This study investigated the effect of solvent dielectric constant on polyphenols recovery and antioxidant activity, using ultrasound-assisted extraction of moringa as a model system. Solvent mixtures of methanol, ethanol, and acetone with water were prepared to achieve a wide dielectric constant range. Extracts were analysed via liquid chromatograph mass spectrometry. Polynomial regression modelling was employed to evaluate the predictive power of dielectric constant on extract yield, total phenolic content (TPC), total flavonoid content (TFC), and antioxidant capacity. Results showed strong correlations between dielectric constant and extract yield, TPC, and antioxidant activity. TFC was highest in low-polarity solvents. Multivariate analysis revealed distinct polyphenol profiles associated with solvent polarity. This is the first study to model extraction performance using dielectric constant, offering a scalable framework for solvent selection. These findings provide practical insights for optimising polyphenol recovery in food and nutraceutical applications.