Abstract

Andrographis paniculata, known as Sambiloto in Indonesia, has been reported to have pharmacological activities with the main active constituent being andrographolide (ANDR). The present study highlighted the research for determining the levels of ANDR by correlating the absorbances of Fourier transform infrared (FTIR) spectra with ANDR contents as quantitatively analyzed by reference method of High-performance liquid chromatography (HPLC) using multivariate calibrations. Andrographis paniculata herbs from several regions were powdered. The powdered samples were measured in terms of FTIR spectra. Besides, a weighted sample was subjected to the extraction procedure and measured using HPLC. Data obtained are subjected to multivariate calibrations. The result indicated that the method was useful to evaluate ANDR content in A. paniculata herb. Partial least square regression (PLSR) using FTIR spectra in the form of a second derivative at the wavenumber regions of 3,700–665 cm−1 was finally preferred for the quantitative analysis of ANDR with Coefficient of determination (R2 ) values of 0.9997 in the calibration model and 0.9765 in the validation models. The values of Root mean square error of calibration (RMSEC) and Root mean square error of prediction (RMSEP) obtained were 0.005 and 0.055, respectively. Due to its capability of providing a high value of R2 and low values of RMSEC and RMSEP, the application of PLSR using the variable of FTIR spectra at selected conditions could be an effective alternative method for quantitative analysis of ANDR.

Key words: Andrographis paniculata, FTIR spectra, HPLC, Partial Least Square Regression, Principal Component Regression