Hydrotropic Extraction of Citral from Cymbopogon flexuosus (Steud.) Wats.

A novel technique for the extraction of citral from the leaves of Cymbopogon flexuosus (Steud.) Wats. using hydrotropic solutions (sodium salicylate and sodium cumene sulfonate) was investigated. The yield of citral was dependent on the concentration of hydrotrope, solid loading, temperature, and size of the plant material. Using the Taguchi method, the extraction was optimized, and both the hydrotropes gave the highest yield of citral at a concentration of 1.75 M, 5% solid loading, a temperature of 30 °C, and a size of 0.25 mm of the plant material. Sodium salicylate gave a better extraction yield of citral than sodium cumene sulfonate. The microscopic analysis of plant leaves provided insight into the extraction mechanism. A kinetic study was carried out to check the extraction efficiency for both the hydrotropes. The hydrotropic solution was successfully recycled. Using hydrotropic extraction, citral could be extracted under normal operating conditions, and the use of traditional organic solvents could be eliminated. As a simple and environmentally friendly technique, hydrotropic extraction could be utilized for the extraction of bioactive compounds from plants.