Analysis of curcumin in curcuma longa and Curcuma xanthorriza using FTIR spectroscopy and chemometrics

Abstract

FTIR spectroscopy in combination with multivariate calibration of Partial Least Square (PLS) has been developed for quantification of curcumin in the ethanolic extracts of Curcuma longa Linn and Curcuma xanthorriza Roxb. The optimization was done by selecting the best wavenumbers regions capable of providing the high coefficient of determination (R 2) and low values of Root Mean Square Error of Calibration (RMSEC). Finally, wavenumbers region of 2000-950 cm -1 was selected for prediction of curcumin in the extracts. The correlation between actual values of curcumin determined by HPLC and FTIR predicted values using FTIR spectroscopy combined with PLS in ethanolic extract of C. longa and C. xanthorriza at 2000-950 cm -1 revealed R 2 values of 0.96 and 0.99, respectively. The RMSEC values obtained are 0.299 and 0.089 for C. longa and C. xanthorriza, respectively. The high value of R 2 and low value of RMSEC indicated the high accuracy and precision of FTIR spectroscopy for quantification of curcumin in the extracts. These results indicated that FTIR spectroscopy combined with PLS is an alternative technique for determination of curcumin in Curcuma species. The developed method (FTIR spectroscopy) is rapid, no sample preparation and not involving excessive solvents and reagents.