Extraction of curcumin and curcuminoids: From conventional methods to innovative extraction using deep eutectic solvents

Abstract

This review compares the methods for extracting curcumin and curcuminoids from turmeric (Curcuma longa L.) and focuses on the use of deep eutectic solvents as a new approach. Conventional techniques such as Soxhlet extraction and maceration, as well as advanced methods such as ultrasound-assisted, microwave-assisted, and supercritical fluid extractions, are examined. Each method is analyzed for extraction efficiency and yield of the curcuminoids. This review explores the influence of extraction parameters, such as temperature, time, and solid-to-solvent ratio, on extraction efficiency. The application of deep eutectic solvents offers significant advantages for enhancing extraction. These solvents offer superior yields, enhanced chemical stability, and increased environmental sustainability compared with conventional organic solvents. The integration of deep eutectic solvents with advanced extraction technologies, such as microwave- and ultrasound-assisted extraction, has the potential to further optimize the extraction efficiency while minimizing energy consumption. Additionally, the synergistic effect observed when combining supercritical fluid extraction with deep eutectic solvents may lead to substantial improvements in extraction yields over traditional solvent-based techniques. This review presents a comprehensive assessment of the extraction methods currently employed for curcumin and curcuminoids, emphasizing the promising role of deep eutectic solvents in the development of more efficient and sustainable extraction processes for future applications in pharmaceuticals, functional foods, cosmetics, and dietary supplements.