Chemical Properties and Therapeutic Potential of Citral, a Monoterpene Isolated from Lemongrass

Background: Citral is one of the main components of lemongrass oil present at a concentration of 65-85% approximately and is generally separated by steam refining. It is an important component in the manufacturing of scents, citrus chemicals, cosmetics, food and pharmaceutical products. Objectives: This article aims at reviewing the published literature to highlight the metabolism, extraction strategies and therapeutic significance of citral for improving the scope of its application in the food and pharma industry. Discussions: Apart from steam refining, there are other techniques like solvent extraction, supercritical fluid extraction and ultrasonication by which citral can be extracted and the method of extraction defines its quality. It is an unstable molecule and undergoes rapid deterioration on exposure to air. Citral is biosynthesized by the plants through the 5 carbon precursor isopentenyl diphosphate (IPP) units utilizing two diverse biochemical pathways, acetate– mevalonate (acetate– MVA) pathway or 2C-methylerythritol-4-phosphate (MEP). Orally Citral was absolutely digested in the gastrointestinal tract and its metabolism leads to the discharge of metabolites which include a number of acids and a biliary glucuronide. There is no scientific evidence about the long term bioavailability of citral in the body and it has no adverse effect on tissue related to its accumulation and delayed excretion. Citral exhibits various important therapeutic properties like antimicrobial, antioxidant, anticancer, anti-diabetic and anti-inflammatory. Conclusions: Citral is a potent biomolecule with various important biological activities and therapeutic implications. Strategies are required to increase the stability of citral which could increase its applications.