Ultra-rapid, enhanced and eco-friendly extraction of four main flavonoids from the seeds of Oroxylum indicum by deep eutectic solvents combined with tissue-smashing extraction

Can we predict the exact chemical properties of a green solvent using physics and thermodynamics? Researchers have unlocked a theoretical blueprint to master botanical extraction.

Scientists set out to study and model how sorbitol-based natural deep eutectic solvents (NADES) extract biologically active substances from Glycyrrhizae roots. Using theoretical fundamentals rooted in statistical physics, thermodynamics, and physical chemistry, the team analyzed simple maceration processes with a plant-to-solvent ratio of 1:10 at 25 °C over 24 hours. They evaluated standards like licuroside and glycyram through advanced techniques, including RP-HPLC, differential scanning calorimetry, and impedance spectroscopy.

Testing various formulations—such as a sorbitol, malic acid, and water NADES, a glycerin-modified variant, and sorbitol-ethanol-water mixtures—revealed striking correlations. Regression equations for sorbitol-based solvents matched theoretical predictions with impressive determination coefficients: R2e = 0.993 for glycyram and R2e = 0.976 for licuroside.

Crucially, the team discovered that dielectric constants serve as a powerful compass. A sorbitol-based NADES with a dielectric constant around 33 proved equivalent in extraction performance to a specific sorbitol-ethanol-water solvent, while modified versions showed how yields shift within specific dielectric ranges. This theoretical framework successfully explains extraction mechanisms and allows for the targeted search of optimal green solvents.

Key Points

• Rooted in statistical physics and thermodynamics
• High determination coefficients for glycyram and licuroside
• Dielectric constants guide optimal solvent selection