Kinetic modeling of ultrasound-assisted extraction of dieckol from Ecklonia cava using a choline chloride-based natural deep eutectic solvent

What if the key to unlocking a seaweed's powerful antioxidant lies in a solvent made from natural ingredients? Discover how a green chemistry approach is revolutionizing the extraction of dieckol from Ecklonia cava.

In the quest for sustainable science, researchers have turned to Natural Deep Eutectic Solvents (NADES) as a green alternative to traditional solvents. These mixtures, often derived from sugars, alcohols, and organic acids, are not only environmentally friendly but also highly effective at extracting bioactive compounds. In a recent study, scientists used ultrasound-assisted extraction (UAE) to pull dieckol, a potent antioxidant, from the brown seaweed Ecklonia cava, employing a choline chloride-based NADES.

After screening eight different NADES formulations and a conventional solvent, the team found that choline chloride–acetic acid (CCAC) at a 1:1 molar ratio with 50% water content performed exceptionally well, yielding a dieckol content of 31.45 mg/g—higher than other NADES and ethanol. To understand the extraction mechanism, they applied second-order kinetic modeling with varying water content. The model revealed that CCAC with 40% water had the highest capacity (Ce = 29.67 mg/g), while 60% water gave the fastest extraction rate (k = 0.12 mg/g·min).

The extracted dieckol also exhibited strong antioxidant activity in DPPH and ABTS+ assays. Additionally, the study compared structural and viscosity changes between CCAC with and without water, highlighting the importance of water in the solvent's performance. This eco-friendly approach offers a promising alternative for efficient dieckol extraction, aligning with green chemistry principles.

Key Points

• CCAC (1:1, 50% water) gave highest dieckol: 31.45 mg/g
• Second-order kinetic model: 40% water best capacity, 60% best rate
• Dieckol extract showed strong DPPH and ABTS+ antioxidant activity