ANTIOXIDANT ACTIVITY OF ACTIVE FRACTIONS AND ISOLATES FROM ETHANOL EXTRACT OF YACON LEAF (Smallanthus Sonchifolius) USING DPPH AND FRAP METHODS

Abstract

Yacon leaves (Smallanthus sonchifolius) are rich in secondary metabolites that contribute to their antioxidant activity. This study was conducted to assess the antioxidant capacity of the ethanolic extract, fractionated samples, and an active isolate derived from yacon leaves using DPPH and FRAP assays. The extraction process involved maceration using 70% ethanol, followed by liquid–liquid partitioning with n-hexane and ethyl acetate. Subsequently, the ethyl acetate fraction was further purified through radial chromatography to obtain the active isolate. Phytochemical characterization was carried out using Thin Layer Chromatography (TLC). Phytochemical evaluation revealed that all examined compound groups were present in the ethanolic extract. In contrast, the ethyl acetate fraction was characterized by the presence of flavonoids, phenolics, and terpenoids, while the n-hexane fraction predominantly contained terpenoids and steroids. Antioxidant activity was evaluated based on IC?? values. The DPPH assay revealed IC?? values of 60.74 µg/mL for the extract, 30.03 µg/mL for the ethyl acetate fraction, and 109.66 µg/mL for the isolate. Similarly, the FRAP assay yielded IC?? values of 81.63 µg/mL, 42.48 µg/mL, and 136.90 µg/mL, respectively. Overall, the ethyl acetate fraction demonstrated the highest antioxidant activity among the tested samples, although its effectiveness remained lower than that of vitamin C, which served as the positive control. These results suggest that the ethyl acetate fraction of yacon leaves holds considerable potential for development as a natural antioxidant source. Keywords: Smallanthus sonchifolius, antioxidant, DPPH, FRAP, fraction, isolate