Tetrahydrocurcumin as a stable and highly active curcumin derivative: A review of synthesis, bioconversion, detection and application

Tetrahydrocurcumin (THCu) is one of the major reduction metabolites of curcumin (CUR), which is a well-known yellow food pigment from turmeric with strong antioxidant, anti-inflammatory, and antibacterial properties. THCu exhibits better solubility, stability, bioavailability than CUR and similar pharmacological activities. In recent years, the market demand for the colorless THCu has a large growth for its application in the field of functional foods and cosmetics due to its strong antioxidant and skin-whitening function. Current industrial production mainly relies on chemical synthesis. The environmental-friendly and good-selectivity synthesis methods like microbial/enzymatic transformation might be better alternative. Several microorganisms have been reported with the capability of CUR reduction. Good-selectivity enzymes also have been characterized like alcohol dehydrogenase from equine liver and curcumin reductase from gut bacteria. This review focuses on the production technology of THCu and summarizes researches on its new chemical synthesis strategies, possible bioconversion methods, detection methods and potential applications.