Evaluation of structurally different ionic liquid-based surfactants in a green microwave-assisted extraction for the flavonoids profile determination of mangifera sp. And passiflora sp. leaves from canary Islands

What if the key to unlocking nature's hidden flavonoids lies in a liquid that's both green and surprisingly versatile? Scientists have found a way to extract these bioactive compounds from mango and passionfruit leaves using ionic liquid-based surfactants and microwaves—no harsh solvents needed.

Flavonoids are powerful antioxidants found in plants, but getting them out is often a messy, toxic affair. Now, researchers have turned to ionic liquids—salts that are liquid at room temperature—with surface-active properties to act as green solvents. They combined these with microwave-assisted solid-liquid extraction, a technique that uses microwave energy to heat samples quickly and efficiently.

The team optimized the process using response surface methodology and the Box-Behnken design, a statistical approach to fine-tune conditions. They tested six different ionic liquid-based surfactants, varying in core structure (imidazolium, guanidinium, pyridinium) and side chain length. The winner? Decylguanidinium chloride ([C10Gu+][Cl–]), which stood out for its superior extraction efficiency and low cytotoxicity.

With this optimized method, they could analyze just 50 mg of plant material using only 525 µL of the surfactant solution at 930 mM, with 10.5 minutes of microwave irradiation at 30°C and 50 W. This is simpler, faster, and greener than previous methods. The approach successfully determined flavonoids like rutin, quercetin, and apigenin in leaves from the Canary Islands, offering a promising path for sustainable bioactive compound profiling.

Key Points

• Ionic liquid-based surfactants enable green microwave extraction of flavonoids.
• Decylguanidinium chloride shows superior performance and low toxicity.
• Method uses 50 mg sample, 525 µL solvent, 10.5 min at 30°C.