Phenolic compounds of sugar beet (Beta vulgaris L.): Separation method, chemical characterization, and biological properties

Sugar beet (Beta vulgaris L.) is a good source of bioactive compounds. However, information on the biological properties of sugar beet root is limited and its beneficial effects have not been completely understood. In this work, 10 phenolic compounds have been separated and identified in various parts of sugar beet for the first time, including the most abundant epicatechin (31.16 ± 1.89 mg/100 g), gallic acid (30.57 ± 2.69 mg/100 g), and quercetin‐3‐O‐rutinoside (30.14 ± 3.63 mg/100 g). The biological activity tests indicated that sugar beet peel potently scavenged the nitric oxide and DPPH (2,2‐diphenyl‐1‐picrylhydrazyl) free radicals with IC(50) values of 88.17 ± 05.14 and 28.77 ± 0.62 μg/ml, respectively. In addition, sugar beet peel exhibited the highest reducing power, IC(50) values of 11.98 ± 1.20 μg/ml, and the highest ion‐chelating activity, IC(50) values of 48.52% and 55.21% for cupric and ferrous ions at 250 μg/ml, respectively. Compared to synthetic antioxidants, sugar beet showed promising biological activities, which could be considered further in future studies.