Antioxidant potential of two varieties of Sesamum indicum L. collected from Indonesia

OBJECTIVES: In this study, we aimed to determine the antioxidant activities of two varieties of sesame (Sesamum indicum L.) seeds using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), and ferric reducing antioxidant power (FRAP) method, and to investigate the correlation between total phenolic as well as flavonoid contents and antioxidant activities of the extracts. METHODS: The antioxidant activities were determined using DPPH, ABTS, and FRAP assays, and the total phenolic content (TPC) and total flavonoid content (TFC) were measured by ultraviolet (UV)-Vis spectrophotometry. The correlation between total phenolic and flavonoid contents and DPPH IC(50), ABTS IC(50,) and FRAP EC(50) values was analyzed by Pearson's method. RESULTS: The IC(50) DPPH values of all sesame seed extracts were in the range of 8.88–44.21 μg/mL and IC(50) ABTS values were in the range of 24.91–141.19 μg/mL. EC(50) FRAP value ranged from 222.40 to 872.57 μg/mL. The highest TPC of 1.57 g gallic acid equivalent (GAE)/100 g was observed in ethanolic extract of black sesame seed, while the highest TFC of 4.29 g quercetin equivalent (QE)/100 g was observed in ethyl acetate extract of white sesame seeds. The TPC in black sesame seed extract was significantly negative correlated with IC(50) ABTS value (r = −0.828, p < 0.01) and EC(50) FRAP value (r = −0.976, p < 0.01). CONCLUSIONS: All sesame seed extracts were categorized as very strong antioxidants by DPPH assay. Phenolic compounds in black sesame seeds were found to be the major contributors to antioxidant activities by using ABTS and FRAP methods. White and black sesame seeds have the potential to be developed as sources of natural antioxidants.