This study was conducted in order to investigate the reduction activity of red ginseng extract (RGE; Panax ginseng, C. A. Meyer) on hydroxyl radical (·OH) using an electron spin resonance (ESR) spectrometer and spin-trapping techniques. ·OH generated by a Fenton Reaction System was trapped by 5, 5-dimethyl-l-pyrroline-N oxide (DMPO). The decay rate showed approximately pseudo-firs order kinetics over the period of measurement (by 10 min), and the half lifetime of the DMPO/·OH signal was estimated as approximately 8.15 min. However, the half lifetime of RGE/·OH was estimated as approximately 7.5 min, and the half lifetime of RGE was higher than that of DMPO/·OH adduct only. The order of reduction activities was ascorbic acid > N, Nʹ-dimethylthiourea (DMTU) > RGE > trolox > mannitol in the Fenton Reaction System. Thus, these observations indicate that RGE reaction with ·OH has relative reduction activity. The second-order rate constant of RGE/·OH may be 3.5~4.5 × 109 M-¹ ∙ S-¹.

• Ki-Wan Oh(College of Pharmacy, Chungbuk National University) Corresponding author
• Jin-Yi Han(Research Institute of Veterinary Medicine Chungbuk National University)
• Jin-Tae Hong(College of Pharmacy, Chungbuk National University)
• Sang-Yoon Nam(Research Institute of Veterinary Medicine Chungbuk National University)