Comparative assessment of various extraction approaches for the isolation of essential oil from polygonum minus using ionic liquids

Abstract

The recent trend of green consumerism in the modern society has triggered the use of plant-derived chemicals in the food, cosmetics, and fragrance industries. Ionic liquids emerged as an effective solvent for extraction of bioactive compounds from numerous plant resources. The objective of this research was to study the ionic liquid-assisted extraction of essential oil from polygonum minus and to compare the impact of various processing methods such as; microwave, ultrasonic, reflux and mechanical stirring on the yield of essential oil. Ionic liquids with various anions (NTf2, Cl, and Ac) and cations (AMIM, BMIM, and HMIM) were investigated. The performance of these ionic liquids was also compared with the organic solvent such as toluene, pentane, and hexane. The results indicated the cationic and anionic components exhibit remarkable impact on the extraction efficiency of the respective ionic liquids. In addition different processing parameter including extraction time, concentration and solid-liquid ratio were also optimized for all processing techniques employed. The use of Clevenger apparatus in combination with the ionic liquids based various processing techniques was also explored. The combination of Clevenger apparatus with ionic liquid based microwave-assisted extraction (ILMAE) technique showed the highest extraction efficiency of essential oil under the optimized condition of 21min and 60°C using [AMIM] Ac. We believe the present work would open for a new pathway for ILs based green extraction of a natural product from renewable resources.