Synergistic action of the antioxidative components in roasted sesame seed oil: (Marked antioxidative activity of seed oils developed by roasting of oil seeds Part 2)

Abstract

To elucidate the components contributing to the strong antioxidative activity of roasted sesame seed oil, the oil roasted at 230°C for 15 min was diluted with n-hexane and passed through an Amberlite XAD-7 column. Most of the antioxidative products were adsorbed and could be separated from the major oil components. These were eluted with ethyl acetate as brown products. The products were then chromatographed on silica gel column and separated from the three known antioxidative components in the oil, i.e. γ-tocopherol, sesamol and sesamin (newly identified as a weak antioxidant), to give ethyl acetate-eluate and methanol-eluate brown products. Each of these products, as well as the three known antioxidative components, showed antioxidative activity, but, the activity of each alone was not so strong to explain the activity of the oil. Thus the synergistic effect of various combinations of the brown methanol-eluates and the three previous known components was examined. Synergistic effect was significantly observed when γ-tocopherol was involved in the combinations. The highest antioxidative activity was obtained with the combination of the brown product, γ-tocopherol, sesamol, and sesamin. These results suggest the importance of the synergistic effect in the activity of roasted sesame oil.