Natural deep eutectic solvent-based extraction of 3-deoxyanthocyanidins from sorghum bran: COSMO-RS screening, optimization, compositional profiling and mechanisms

In this study, a green and efficient extraction approach based on natural deep eutectic solvents for 3-deoxyanthocyanidins (3-DOA) from sorghum bran was developed. Solvents of choline chloride-propionic acid (ChPA, molar ratio 1:2) were selected based on computational and experimental screening. Under the optimal extraction conditions (water content: 21.5 %, liquid/solid ratio: 77.3 mL/g, temperature: 90 °C, time: 67 min), 3-DOA yield was 0.86 ± 0.01 apigeninidin mg/g. Four 3-DOA were identified in extracts using HPLC-QTOF-MS/MS, with apigeninidin being the most abundant. Extracts obtained using ChPA exhibited highest 3-DOA content and strongest in vitro antioxidant activities than conventional solvents. Additionally, the mechanism for higher extraction efficiency of ChPA compared to conventional solvents were explored. ChPA induced the most pronounced cell wall disruption, leading to a higher release of 3-DOA. Molecular dynamics simulations suggested that strong electrostatic interactions, including hydrogen bonding, and reduced self-aggregation driven by van der Waals forces contributed to the enhanced extraction efficiency.