Natural Deep Eutectic Solvents for the Extraction of Triterpene Saponins from Aralia elata var. mandshurica (Rupr. & Maxim.) J. Wen

Can we finally swap out traditional laboratory alcohols for greener, safer plant solvents without losing extraction power? Researchers are putting eco-friendly designer liquids to the test on a valuable medicinal root.

The roots of the medicinal plant Aralia elata are packed with biologically active triterpene saponins, typically captured using conventional alcohols like methanol and ethanol. While natural deep eutectic solvents (NADES) have emerged as low-toxicity alternatives for isolating natural products, their specific ability to extract triterpene saponins remained entirely unexplored—until now.

By employing a targeted LC-MS quantitative approach, scientists evaluated seven different acid-based NADES to uncover their true extraction potential. High-resolution mass spectrometry successfully annotated 20 triterpene saponins across the root material, root bark, and root core, identifying 9 of these compounds in the roots for the very first time.

All tested NADES successfully recovered the target saponins. Peak efficiency arrived via specific mixtures: a 1:1 blend of choline chloride and malic acid, alongside a 1:3 mix of choline chloride and lactic acid. Remarkably, these NADES outperformed both water and ethanol for 13 distinct metabolites, proving their viability as stellar, alcohol-free replacements in future laboratory extraction protocols.

Key Points

• First application of NADES for extracting Aralia elata triterpene saponins
• 9 triterpene saponins identified in the roots for the first time
• Choline chloride mixtures outperformed water and ethanol for 13 metabolites