Deep eutectic solvents (DESs) offer a reliable and environmentally friendly method for extracting polyphenols from medicinal plants, which are known for their health benefits. Traditional extraction methods can be expensive and involve hazardous solvents. Choline chloride-based DES formulations are commonly used. However, acetylcholine, a derivative of choline, has received little attention. Therefore, our current study explores the potential of acetylcholine-based DESs for extracting polyphenols from green coffee. To achieve this, we synthesized a DES comprising acetylcholine chloride and citric acid in a 1:1 ratio (ACCH:CA = 1:1) using ultrasound and microwave radiation.

To reduce the high viscosity, 20% water was added to the total mass of the deep eutectic solvents (DESs). Both variants of DESs were then utilized in ultrasonic extraction processes to extract polyphenols from green coffee at a bath temperature of 50°C. The polyphenolic content of the green coffee extracts was analyzed using HPLC-PDA. To assess the efficiency of polyphenol extraction using DESs, a standard extract was prepared using 70% methanol. The analysis revealed the presence of caffeoylquinic acids (CQAs), including mono-CQA, di-CQA, and feruloylquinic acid (FQA), in the green coffee samples. The results showed that DESs synthesized via microwave radiation extracted higher amounts of polyphenols from green coffee compared to those obtained through ultrasound. The extraction yields using DESs with an ACCH:CA ratio of 1:1 ranged from 50% to 85%, while ultrasound-derived DESs resulted in yields of approximately 30% to 75%. These findings highlight the effectiveness of an acetylcholine-based DES as a natural solvent for extracting health-promoting bioactive components. Moreover, the method of DES synthesis significantly impacts its performance.