FTIR-based fingerprinting combined with chemometrics for discrimination of Sonchus arvensis leaves extracts of various extracting solvents and the correlation with its antioxidant activity

Abstract

Sonchus arvensis, or known locally in Indonesia as tempuyung, is acknowledged to have many biological activities, including antioxidant activity. This study aimed to cluster the leaves extracts based on the extracting solvent and to determine functional groups that significantly contribute to the antioxidant activity. From the water, 10%, 30%, 50%, 70% ethanol, and absolute ethanol extracts, we analyzed the total phenolics content (Folin-Ciocalteu method), antioxidant activity (DPPH method), and the FTIR spectra. The 70% ethanol extract exhibited the highest total phenolics and antioxidant activity. The extracts were grouped based on the extracting solvent using the principal component analysis (PCA) with 95% total variance from its principal component 1 and 2. The partial least square (PLS) regression was employed for finding a functional group that are responsible for the antioxidant activity in the sample extract. PLS regression predicted that the -OH and the C-O groups attributed to the phenolic compounds give a significant contribution to the antioxidant activity of the S. arvensis leaf extracts.