Orostachys species have been recognized as medicinal herbs in East Asia. Although O. fimbriata is known as a traditional medicine, its antioxidant properties have not been investigated compared to other Orostachys species. In this study, we characterized the antioxidant compounds and determined the antioxidant activity of O. fimbriata for the first time. As a result, 1 g of O. fimbriata extracts contains 288.5 ± 7.4 mg polyphenols, which contains 159.7 ± 8.3 mg flavonoids. In particular, 21.6%, 6.6%, and 2.6% of the total flavonoids were identified as epicatechin gallate, quercetin, and kaempferol, respectively, by LC-MS system. The DPPH IC50, ABTS IC50, and FRAP value of the extracts was determined to be 27.6 ± 5.5 μg/mL, 125.7 ± 6.0 μg/mL, and 115.0 ± 4.4 mmol/L, respectively. These activities were 30–57% of the positive control, ascorbic acid. In conclusion, it was demonstrated that O. fimbriata has outstanding antioxidant properties. This study highlights the need for further investigations toward in-depth research on the pharmacological functions of O. fimbriata.
