Physicochemical properties of choline chloride-based natural deep eutectic solvents (Nades) and their applicability for extracting oil palm flavonoids

What if agricultural waste could be unlocked using designer green liquids that are safe for cells yet powerful enough to extract valuable plant compounds? Researchers are turning to customized natural deep eutectic solvents to transform oil palm leaves into a goldmine of bioactives.

Oil palm plantations leave behind mountains of leaf biomass rich in flavonoids, which are valuable bioactive metabolites. To capture these compounds sustainably, scientists synthesized six natural deep eutectic solvents (NaDES) by combining choline chloride with various hydrogen bond donors like sugars, glycols, and organic acids using a direct heating technique. These transparent liquids were thoroughly evaluated for their physical properties, thermal behavior, and biological safety.

The results reveal an exciting profile. These tailor-made solvents proved to be stable, easy-to-use, and exhibited low cytotoxicity on cultured fibroblast cells. Crucially, hydrogen bonding interactions drive the formation of these unique mixtures. When tested for extraction efficiency using advanced chromatography, the choline chloride and glycerol combination matched aqueous methanol in extracting luteolin and apigenin derivatives from oil palm leaves.

Meanwhile, the choline chloride and lactic acid mixture stood out for its high free radical scavenging abilities. This research highlights these safe, green solvents as a promising alternative technology for upcycling agricultural biomass.

Key Points

• Six NaDES synthesized from choline chloride and diverse compounds
• Choline chloride-glycerol extracts flavonoids as efficiently as aqueous methanol
• Low cytotoxicity and high radical scavenging showcase green potential