Natural Deep Eutectic Solvent (NaDES) Extraction, HPLC-DAD Analysis, and Antioxidant Activity of Chilean Ugni molinae Turcz. Fruits

What if the secret to unlocking the antioxidant power of a Chilean superfruit lies not in harsh chemicals, but in a green, sugar-like solvent? A new study shows that natural deep eutectic solvents can outperform traditional methods in extracting phenolics from murta berries.

The demand for sustainable extraction methods is rising, and murta—a Chilean fruit with a rich ethnopharmacological history—is stepping into the spotlight. Researchers tested seven choline chloride-based natural deep eutectic solvents (NaDES) paired with ultrasound-assisted extraction against a conventional methanol:formic acid mix. The star performer? A 1:2 choline chloride:1,2-propanediol system (M2), which pulled out the highest levels of total phenolics (64.87 mg GAE/g) and flavonoids (35.38 mg QE/g), while showing formidable antioxidant activity (DPPH IC50 of 1.05 µg/mL and ORAC value of 40,291 µmol TE/g).

But not all NaDES were created equal. The conventional solvent (M8) actually boasted superior FRAP and ORAC values, though its phenolic and flavonoid yields lagged behind—a reminder that solvent choice shapes what you get. HPLC-DAD analysis revealed that certain NaDES, especially M5 (choline chloride:oxalic acid, 1:1), favored flavonoid and anthocyanin extraction. Multivariate and PCA analyses showed distinct chemical profiles, with NaDES extracts clustering separately from M8, and Pearson correlations linked antioxidant capacity to major flavonoids.

This isn't just lab trivia. NaDES combined with ultrasound offers a green, efficient, and selective route to recover bioactives from native fruits—paving the way for applications in foods, nutraceuticals, and health products. The future of extraction might just be a little sweeter.

Key Points

• NaDES M2 (choline chloride:1,2-propanediol) recovered highest phenolics and flavonoids.
• M2 showed strong antioxidant activity (DPPH IC50 1.05 µg/mL; ORAC 40,291 µmol TE/g).
• NaDES extracts had distinct chemical profiles, clustering separately from conventional solvent.