Extraction of Bioactive Metabolites from Achillea millefolium L. with Choline Chloride Based Natural Deep Eutectic Solvents: A Study of the Antioxidant and Antimicrobial Activity

What happens when you mix green chemistry with traditional medicinal plants? By pairing choline chloride with clever hydrogen bond donors, scientists have unlocked a remarkably potent way to extract nature's pharmacy.

Meet *Achillea millefolium L.*, a plant packed with valuable bioactive compounds. For the first time, researchers put natural deep eutectic solvents—or NADES—to the test, pairing choline chloride with five different hydrogen bond donors like lactic acid and urea. Using ultrasound-assisted extraction, the team compared these custom-made green solvents against traditional solvents like water, methanol, and ethanol.

The results speak volumes. A lactic acid-based NADES yielded the highest total phenolic content and topped the charts in antioxidant activity via FRAP analysis, while a urea-based version triumphed against ABTS radicals. Dominant compounds like chlorogenic acid, luteolin, and apigenin showed up across the board.

Beyond antioxidants, these extracts flexed some serious microbial muscle. Tested against four bacteria and two yeasts, the lactic acid NADES extract reigned supreme with the lowest minimum inhibitory and bactericidal concentrations. Meanwhile, plain water extracts trailed far behind as the weakest performers.

Key Points

• Tested choline chloride NADES with five hydrogen bond donors
• Lactic acid NADES showed highest phenolic content and antioxidant activity
• Lactic acid NADES exhibited the strongest antibacterial and antifungal properties