Free radical scavenging behavior of antioxidant compounds of sesame (sesamum indicum L.) in DPPH(*) system.

The free radical scavenging capacity (RSC) of antioxidants from sesame cake extract was studied using the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH(*)()) on a kinetic model. Pure lignans and lignan glycosides isolated from methanolic extract by preparative HPLC were used in the study. To understand the kinetic behavior better and to determine the RSC of sesame antioxidants, the second-order rate constant (k(2)) was calculated for the quenching reaction with [DPPH(*)] radical. The k(2) values of the sesame antioxidants were compared with those of butylated hydroxytoluene and alpha-tocopherol. The k(2) values for sesamol, sesamol dimer, sesamin, sesamolin, sesaminol triglucoside, and sesaminol diglucoside were 4.00 x 10(-)(5), 0.50 x 10(-)(5), 0.36 x 10(-)(5), 0.13 x 10(-)(5), 0.33 x 10(-)(5), and 0.08 x 10(-)(5) microM(-)(1) s(-)(1), respectively.