Separation and determination of the physico-chemical characteristics of curcumin, demethoxycurcumin and bisdemethoxycurcumin

The objective of this work was to separate and determine the physico-chemical and color characteristics of isolated curcuminoid pigments. Thin-layer chromatographic separation of curcuminoid pigments was possible on silica gel 60G plates using dichloromethane:methanol, 99:1. The preparative separation of curcuminoid pigments was accomplished by crystallization of curcumin in methanol:water and further separation by column chromatography using silica gel 60G impregnated with sodium hydrogen phosphate and dichloromethane as the eluent. The purity of each curcuminoid pigment was confirmed by high performance liquid chromatography and determination of the melting point. The isolated pigments were characterized with respect to ultraviolet, visible, infrared, nuclear magnetic resonance and color characteristics. The molar absorptivity of each pigment was determined. This data can be used for the identification and quantification of individual curcuminoid pigments.