In this study, we investigated the antioxidant activities of Rumex crispus L. root water, ethanol extracts (WE, EE), and various fractions, including n-hexane fractions (HF), dichloromethane fractions (DCMF), ethyl acetate fractions (EAF), n-butanol fractions (BF), and aqueous fractions (AF). In all of the extraction and fractions, the highest total phenolic content was measured as 83.26 mg gallic acid equivalent/g in the EAF, whereas the highest total flavonoid content was measured as 30.67 mg quercetin equivalent/g in the DCMF. 1,1-Diphenyl-2-picrylhydrazyl, hydroxyl, and superoxide radical scavenging activities increased in a concentration-dependent manner in all extracts and fractions. The highest ferric reducing antioxidant power was measured as 135.58 mM FeSO4/g in the EAF, and the remaining were in descending order: EE, AF, DCMF, WE, BF, and HF. The highest Trolox equivalent antioxidant capacity was measured as 5.65 mM TE/g in the EAF, and the remaining were in descending order: DCMF, EE, AF, BF, and HF. Oxygen radical absorption capacity of the EAF and DCMF were 4,817 and 1,790 mM TE/g, and their values were similar or significantly higher than those of ascorbic acid. Reactive oxygen species scavenging activity of EAF was also significantly higher than the control. Overall, these results mean that the various phenols and flavonoids in EAF have antioxidative function, and EAF of Rumex crispus L. root could be useful as an antioxidant agent for heath functional foods.

Keywords: Rumex crispus L. root, extract, antioxidant activity, total phenol, total flavonoid