Optimized probe-ultrasound-assisted extraction of Chlorogenic acids from eggplant (Solanum melongena L.) by-products: Unlocking the phenolic and antioxidant potential of Calyx and leaves

These residues represent promising sources of functional ingredients for nutraceutical, food, and pharmaceutical applications. Among eggplant metabolites, phenolic compounds, particularly chlorogenic acids (caffeoylquinic acids, CQAs), stand out for their health-promoting properties.

This study provides a comprehensive characterization of eggplant pulp, peel, calyx, and leaves as sources of phenolic compounds, with emphasis on CQAs. Non-conventional extraction techniques, including microwave- and ultrasound (bath- and probe)-assisted extraction were compared and optimized through a Design of Experiments to maximize 5-CQA (chlorogenic acid) recovery while minimizing isomer degradation. Antioxidant capacity was evaluated through spectrophotometric assays, and cytotoxicity was assessed in Caco-2 cells to determine extract functionality and safety.