Acmella oleracea Metabolite Extraction Using Natural Deep Eutectic Solvents

For plant metabolite extraction, natural deep eutectic solvents (NADESs) have many benefits over conventional solvents and ionic liquids. These advantages include high solubility and extraction ability, a low melting point (<100 °C), low toxicity, environmental friendliness, recyclability, and better biodegradability. This study analyses a natural deep eutectic solvent for Acmella oleracea (A. oleracea) metabolite extraction, considering the following process parameters: temperature, component ratio in the eutectic solvent, water addition, solid/liquid ratio, and extraction duration. NADESs were synthesised using a simple heating method, and the synthesis of the NADESs was verified by Fourier transform infrared spectroscopy (FTIR). In terms of total polyphenol content (TPC) and flavonoid content (TFC), the betaine/propanediol ratio in a NADES of 1:3 and S/L = 1:5 yielded the highest efficiency. A value of 8.37 mg GAE/mL was obtained for TPC by ultrasound-assisted extraction with 40% water addition, 25 °C extraction temperature, and 60 min contact time. The best result in terms of TFC was 14.50 mg QE/mL obtained through ultrasound-assisted extraction with 0% water added, 25 °C extraction temperature, and 60 min contact time.