Development of a colorlessCentella asiatica(L.) Urb. extract using a natural deep eutectic solvent (NADES) and microwave-assisted extraction (MAE) optimized by response surface methodology

What if the greenest way to extract a skincare superstar also produced a better, clearer result? A new process swaps harsh solvents for a natural eutectic mixture and microwaves, delivering higher yields of active compounds from Centella asiatica.

Centella asiatica, the famed 'herb of longevity,' is a powerhouse in health and beauty products. But extracting its valuable triterpene saponins—like madecassoside (MS) and asiaticoside (AS)—often relies on harsh organic solvents. A new study offers a cleaner, more efficient path forward, combining natural deep eutectic solvents (NADES) with microwave-assisted extraction (MAE).

The winning NADES formula paired acetylcholine chloride, malic acid, and water. This eco-friendly cocktail outperformed traditional ethanol-based methods, yielding 21.7 mg/g of MS and 12.7 mg/g of AS from dry weight. That's a significant boost compared to over 80% ethanol, which only managed 13.3 mg/g and 7.80 mg/g, respectively. The resulting extract also showed superior antioxidant activity (IC50 = 0.26 mg/mL) and boasted a lighter, less green color—a major plus for cosmeceutical formulations.

To fine-tune the process, the team used response surface methodology (RSM). Their statistical models were robust, with R² values above 0.93 and validated accuracy exceeding 80% under optimal conditions: just 30 seconds of microwave power at 300 W with a liquid-to-solid ratio of 20 mL/g. This fast, energy-efficient, and solvent-free approach marks a significant step toward truly sustainable extraction of this botanical treasure.

Key Points

• NADES + MAE boosts madecassoside yield to 21.7 mg/g.
• Eco-friendly extract shows higher antioxidant activity than ethanol.
• Validated model: 30s, 300W, 20 mL/g achieves >80% accuracy.