The isolation of curcumin from the rhizomes of C. longa was initially carried out by Vogel and Pelletierin in 1815 [26,36]. Curcumin was first purified by Vogel Jr. in 1842 [26]. In 1910, Milobedeska et al. published a report on the structure of curcumin, identifying it as diferuloylmethane, following several decades of research. Lampe and Milobedeska successfully synthesized curcumin in 1913 [26,37]. In 1953, Srinvansen recorded the chromatographic separation and quantification of curcumin [26].

The process of curcumin extraction is a crucial step in the recovery of the bioactive compound from the plant matrix [38]. During the extraction process, specific solvents are used in accordance with predetermined procedures, leaving behind insoluble compounds [39]. Curcumin can be extracted using either conventional or advanced techniques. Since conventional extraction methods such as solvent extraction and Soxhlet extraction [7] require a considerable amount of time, organic solvents, cooling water [40], and energy [41], several researchers have applied novel extraction methods such as ultrasound-assisted extraction [42], microwave-assisted extraction [43], enzyme-assisted extraction [44], supercritical fluid extraction [45], and pressurized liquid extraction [46] (Figure 3). Regardless of the technique used, the preparation of the raw material prior to processing and the selection of the best parameters have a significant impact on the efficacy of the extraction technique and the quality of the extract. Typically, phytochemicals are more accessible and the matrix is more easily penetrated by the extraction solvent if the plant material is dried rather than fresh and finely ground as opposed to simply cut into pieces. The solvent-to-plant solid material ratio can also be decreased when the latter is finely pulverized, thus reducing costs [38]. Recirculating the solvent as in a Soxhlet extractor can also lead to the processing of a greater amount of material with less solvent cost and increased extraction yields, as can intense agitation, ultrasounds, microwaves, specific enzymes, or high pressures,.