Isolation, characterisation, and antioxidant activities of flavonoids from chufa (Eleocharis tuberosa) peels

In this paper, chufa peels (Eleocharis tuberosa) were researched for the flavonoid profile for the first time. Twenty flavonoids were isolated and identified, including six new ones, named eleocharins A-F (1-6). Their structures were characterised by spectroscopic methods and compared with published data. The antioxidant activity of the acetone extract, EtOAc fraction, and nBuOH fraction of chufa peels as well as the isolated flavonoids were assessed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical bioassay. The results showed that chufa peels can be regarded as an excellent source of natural antioxidants (mainly flavonoids) and a good additive in the beverage and canning. (C) 2014 Elsevier Ltd. All rights reserved.