Short-chain alcohol/salt-based aqueous two-phase system as a novel solvent for extraction of plant active ingredients: A review

Conventional solvents used to extract plant active ingredients such as water, methanol, ethanol, propanol, etc. have no purification function. Thus, the contents of impurities in the extracts are higher, which increases the difficulty of the subsequent process. An aqueous two-phase system (ATPS) based on short-chain alcohol and salt is a novel solvent, which has the advantages of excellent phase separation effect, high selectivity, low viscosity, low cost, easy recycling, environmental friendliness, and so on. It is a potential alternative for conventional solvents and has been widely used in the extraction of plant active ingredients. This review summarized the research progress of short-chain alcohol/salt-based ATPS for recovery of plant active compounds, including the principle and mechanism, the main factors affecting the efficiency, the applications in recent years, etc., and put forward the future perspective. The present results indicate that alcohol/salt-based ATPS can significantly improve the purity of extracts while obtaining higher extraction efficiency with the aid of ultrasound or microwave. Therefore, alcohol/salt-based ATPS plays an important role in improving the recovery of plant active ingredients, and has a broader application prospect in the industrial production.