Sidaguri (Sida rhombifolia) is one of the herbal components used in traditional medicine. The metabolites of Sidaguri vary depending on their geographical origin. Thus the quality control of Sidaguri is needed. The application of chemometrics in the standardization of herbal medicine is common. One of the analytical techniques widely used for metabolite fingerprinting analysis is FTIR spectroscopy, especially in combination with chemometrics. FTIR spectroscopy possesses several advantages compared to other analytical methods. The objective of this study was to classify Sidaguri from different regions based on FTIR spectra with chemometrics of principal component analysis (PCA) and to correlate the antioxidant activities with FTIR spectra using the multivariate calibration of partial least square regression (PLSR).
The extraction of Sidaguri powder was performed using ultrasound-assisted extraction (UAE) at optimum conditions. The obtained extracts were subjected to antiradical scavenging activities using DPPH (2,2’- diphenyl-1-picrylhydrazyl) and ABTS (2,2′-azinobis-3 ethylbenzothiazoline-6-sulfonic acid) radicals. The PCA result shows that Sidaguri from different regions could be separated using 14 wavenumbers of FTIR spectra based on the PCA’s loading plot. PLSR regression using the second derivative FTIR spectra at wavenumbers of 3662–659 cm–1 could predict radical scavenging activities (RSA) of Sidaguri with R2 values of 0.9636 and 0.9024 for calibration and validation models, with RMSEC and RMSEP values of 1.45% and 2.65%, respectively. It can be concluded that FTIR spectra treated by PCA were reliable for classifying Sidaguri from different regions. At the same time, PLSR was accurate and precise enough to predict the RSA of Sidaguri.
Author: Nanik Siti Aminah
Further explanation regarding this research is presented completely on the article published by journal “Indonesian Journal of Chemistry (Indones. J. Chem., 2021, 21 (6), 1568 – 1576)”
with the title:
“ The Use of Chemometrics for Classification of Sidaguri (Sida rhombifolia) Based on FTIR Spectra and Antiradical Activities”
Abdul Rohman (UGM), Asefin Nurul Ikhtiarini (UGM), Widiastuti Setyaningsih (UGM), Mohamad Rafi (IPB), Nanik Siti Aminah (UNAIR), Muhamad Insanu (ITB), Irnawati Irnawati (UGM), and Djoko Santosa (UGM)
