Studies on Antioxidative Substances in Sesame Seed

Abstract

Our previous study revealed the presence of some potent antioxidative components other than γ-tocopherol and sesamol in sesame seed and oil. In the present study, the effective components were extracted from mashed sesame seed with acetone, followed by removal of triglycerides by freezing. The acetone extract showed strong antioxidative activity with the thiocyanate method and gave 4 active antioxidative substances after a series of chromatographic separations. The molecular formulae were determined to be C₂₀H₂₀O₆ (PI), C₂₀H₂₀O₇ (P2), C₂₀H₁₈O₇ (P3) and C₁₀H₁₀O₄ (P4). Compounds PI and P4 were respectively identified as a bisepoxylignan analogue and trans-ferulic acid. Though preliminary structural data for P2 and P3 indicate them to be a sesamolin analogue and a sesamin analogue, respectively, work is currently underway to confirm this. The antioxidative activities were in the order of P3 > P2 > P1 > P4. The same components were also obtained from the 80% ethanol extractable polar fraction of the sesame oil cake treated with β-glucosidase, which suggested the presence of the active substances also as their glycosides in sesame seed.