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, the local name for tempuyung, is acknowledged to have many biological activities, including the antioxidant activity. This study aimed to cluster the leaves extracts based on the extracting solvent and to determine the functional groups significantly contributing 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 exhibits the highest total phenolics and the highest 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 from the antioxidant constituents present in the sample extract. We predicted by PLS regression that the –OH and the C-O groups are attributed to the phenolics that give a significant contribution to the antioxidant activity of the S. arvensis leaves.