Simple HPLC method for resolution of curcuminoids with antioxidant potential

Development of methodology for qualitative analysis and quantitative separation of individual curcuminoids in curcumin removed turmeric oleoresin (CRTO) and study of antioxidant activity of individual curcuminoids have been achieved in the present study. A simple HPLC protocol was outlined for optimal resolution of curcuminoids (I), (II), and (III) on an Exil-NH(2) column using isocratic elution with a mixture of isopropanol and water. CRTO is shown to be good source for the compounds II and III, as they are in an enriched form. The optimum resolution of the curcumin and its analogs in the present method developed, affords a facile method for estimation of individual curcuminoids in turmeric samples, which is an improvement over the standard AOAC method which estimates only total curcuminoids. The free radical scavenging capacity of pure curcuminoids I, II, and III, as determined by DPPH method at 100 ppm concentration was 88%, 80%, and 68% with IC(50) values being 56, 62, and 73 ppm, respectively. Their antioxidant potential could render them useful as important nutraceuticals or functional food ingredients.