The antioxidant activities of brown pigment, extract of n-hexane and extract of supercritical carbon dioxide extraction of black
sesame seeds were investigated in this study. Kinetics of anti-radical activity showed that the reaction between DPPH and brown
pigment of sesame seed was rapid and reached the steady state in 10 min. Extracts from supercritical carbon dioxide extraction and
n-hexane extraction reacted with DPPH slowly and the absorbance became stable after 35 min. However, a-tocopherol and trolox
were rapid while the kinetic behaviour of BHA was intermediate. The brown pigment of sesame seed also showed a lower EC50 (13.5
lgml1) than the other two extracts and a-tocopherol, which was about 7–10 fold of the antioxidant activity of the supercritical
carbon dioxide extract and the n-hexane extract. The ferric thiocyanate (FTC) method also showed that the brown pigment of sesame
seed provided higher inhibition activity against lipid peroxidation at 200 lgml1 than did the supercritical carbon dioxide extract
an n-hexane extract at 1 mgml1. However, the activities of the supercritical carbon dioxide extract and n-hexane extracts were
significantly higher than that of a-tocopherol. In the linoleic acid system, the brown pigment of black sesame seed showed an equal
antioxidant activity to BHA and higher than trolox and a-tocopherol. The results indicated that the brown pigment of sesame seed
possessed excellent antioxidant activity.
2004 Elsevier Ltd. All rights reserved.