Development of Green Extraction Using Natural Deep Eutectic Solvent (NADES) for Separation Polyphenolic Compounds from Spilanthes acmella

Abstract

Natural deep eutectic solvent (NADES) is an alternative to conventional solvents in polyphenol extraction. Its composition of choline chloride combined with fructose, choline chloride with lactic acid, choline chloride with glycerol, choline chloride with propylene glycol, and choline chloride with proline have been sucessfully set using the thermal mixing method. Choline chloride served as the hydrogen bond acceptor (HBA), while the others acted as hydrogen bond donors (HBDs) at a mole ratio of 1:2. This study aimed to extract polyphenols from the flowers, stalks, stems, and leaves of Spilanthes acmella, using NADESs. The extraction process was conducted by adding 20% water to the mixture with a ratio of the sample to solvent of 1:10 (w/v), for 60 min. The extract concentration was assessed through spectroscopic photometry using the Folin-Ciocalteu method. The result showed that the choline chloride-glycerol NADES was the most appropriate solvent for the extraction of polyphenols from the flowers of the plant. Meanwhile, the best NADES for the extraction from the stems, stalks, and leaves, was the mixture of choline chloride and fructose. The highest polyphenol concentration was obtained in the stems at 2545.192 mg/L. The yield obtained in the stems, leaves, stalks, and flower were 25.452, 6.284, 3.111 and 2.415 mg gallic acid equivalent/g (GAE/g), respectively. These findings suggest that NADES can be used as an eco-friendly alternative solvent for green extraction processes of active compounds from natural materials, especially polyphenols from S. acmella.