A curcuminoid is a linear diarylheptanoid, a relatively small class of plant secondary metabolites that includes curcumin, demethoxycurcumin, and bisdemethoxycurcumin, all isolated from turmeric (curcuma longa). These compounds are natural phenols and produce a pronounced yellow color that is often used to color foods and medicines. Curcumin is obtained from the root of turmeric.
Curcuminoids are soluble in dimethyl sulfoxide (DMSO), acetone and ethanol,[1] but are poorly soluble in lipids. It is possible to increase curcuminoid solubility in aqueous phase with surfactants or co-surfactants.[2] Most common derivatives have different substituents on the phenyl groups.[1] There is an increasing demand for demethoxycurcumin, bisdemethoxycurcumin, and other curcuminoids because of their biological activity.[2]