Antioxidant activities of curcumin, demethoxycurcumin and bisdemethoxycurcumin

Consumers are now increasingly aware of diet-related health problems and therefore, demanding natural ingredients which are expected to be safe and health-promoting. Recently, many studies on health benefits associated with curcumin have been reported. In the present study, an attempt has been made to test individual curcuminoids, such as curcumin, bisdemethoxycurcumin and demethoxycurcumin, for their antioxidant activities by in vitro model systems, such as the phosphomolybdenum and linoleic acid peroxidation methods. Antioxidant capacities of the extracts, as ascorbic acid equivalent (μmol/g) were in the order: curcumin > demethoxycurcumin > bisdemethoxycurcumin. In comparison with butylated hydroxyl toluene (BHT), at 100 ppm, the antioxidant activity, by linoleic acid peroxidation, was found to be highest with curcumin, followed by demethoxycurcumin and bisdemethoxycurcumin. The data obtained by the in vitro models clearly establish the antioxidant potencies of individual curcuminoids. This is the first report on antioxidant activity of individual curcuminoids using the phosphomolybdenum method and linoleic acid peroxidation method.