Green and Non‐conventional Extraction of Bioactive Compounds from Olive Leaves: Screening of Novel Natural Deep Eutectic Solvents and Investigation of Process Parameters

What if an everyday agricultural waste held the key to capturing powerful compounds like oleuropein, a molecule gaining intense attention for its anti-viral activity against SARS-CoV-2? Scientists are now turning to next-generation green chemistry to unlock this hidden potential.

Olive leaves are far more than mere agricultural waste. Packed with valuable bioactive compounds for the pharmaceutical and cosmetic industries, these leaves are stepping into the scientific spotlight. Researchers recently tackled the challenge of extracting these treasures using a smart, non-conventional approach: natural deep eutectic solvents, or NADES, paired with ultrasound-assisted extraction.

By carefully screening variables like solvent type, temperature, and particle size—while optimizing NADES amount and liquid-to-solid ratios—the team successfully mined the leaves for health-boosting compounds. Success varied depending on the exact recipe used.

When using a specific blend of choline chloride, fructose, and water, the team achieved peak total polyphenol and flavonoid yields. Meanwhile, a different sugar-based solvent combination of glucose, fructose, and water triumphed in extracting the highest amounts of valuable oleuropein and caffeic acid.

Key Points

• Green extraction of olive leaf bioactive compounds using NADES
• Choline chloride-fructose-water achieved highest polyphenol and flavonoid yields
• Glucose-fructose-water extracted the highest amounts of oleuropein and caffeic acid