in vitro Antioxidant and Free Radical Scavenging Activities of Yacon (Smallanthus sonchifolius) Tubers

Antioxidant capacity is an important factor indicating nutritional and health value of fruits and vegetables.Yacon is a both edible and medicinal plant,which has some preventing roles for a number of chronic diseases.In this study,to assess the in vitro antioxidant potential of yacon tubers,the 60% methanol extract from yacon tubers was tested for its scavenging capacities against DPPH,ABTS+·,superoxide anion radicals,ferric reducing antioxidant power and ferrous ions chelating capacity.The DPPH radical scavenging assay of the extract showed a trolox equivalent antioxidant capacity (TEAC) of 410.263 mg Trolox /g md,a ascorbic acid equivalent antioxidant capacity (AEAC) of 230.485 mg VC/g md and a median inhibition concentration (IC50) of 1.464 mg/mL,and the ABTS+· radical scavenging assay showed a TEAC of 267.584 mg Trolox/g md,an AEAC of 41.597 mg VC/g md and an IC50 of 1.269 mg/mL,and the TEAC,AEAC and IC50 obtained in the superoxide anion radical assay were 652.816 mg Trolox/g md,101.451 mg VC/g md and 7.720 mg/mL,respectively.These results demonstrate that the extract from yacon tubers has scavenging effect against all DPPH,ABTS+·,superoxide anion radicals.Moreover,the extract also presented high ferric reducing antioxidant power (131.723 mg FeSO4 /g md) and strong ferrous ions chelating capacity (73.193%).