title: Antioxidative effects of Kimchi under different fermentation stage on radical-induced oxidative stress.
abstract: OBJECTIVE
  Kimchi is a traditional Korean fermented vegetable containing several ingredients. We investigated the protective activity of methanol extract of kimchi under different fermentation stages against oxidative damage.
  
  
  METHODS
  Fresh kimchi (Fresh), optimally ripened kimchi (OptR), and over ripened kimchi (OvR) were fermented until the pH reached pH 5.6, pH 4.3, and pH 3.8, respectively. The radical scavenging activity and protective activity from oxidative stress of kimchi during fermentation were investigated under in vitro and cellular systems using LLC-PK1 cells.
  
  
  RESULTS
  Kimchi exhibited strong radical scavenging activities against 1,1-diphenyl-2-picrylhydrazyl, nitric oxide, superoxide anion, and hydroxyl radical. In addition, the free radical generators led to loss of cell viability and elevated lipid peroxidation, while treatment with kimchi resulted in significantly increased cell viability and decreased lipid peroxidation. Furthermore, the protective effect against oxidative stress was related to regulation of cyclooxygenase-2, inducible nitric oxide synthase, nuclear factor-κB p65, and IκB expression. In particular, OvR showed the strongest protective effect from cellular oxidative stress among other kimchi.
  
  
  CONCLUSIONS
  The current study indicated that kimchi, particularly OptR and OvR, played a protective role against free radical-induced oxidative stress. These findings suggest that kimchi is a promising functional food with an antioxidative effect and fermentation of kimchi led to elevation of antioxidative activity.
authors.affiliation: Department of Food Science and Nutrition and Kimchi Research Institute, Pusan National University, 2, Busandaehak-ro 63beon-gil, Geumjeong-gu, Busan 609-735, Korea.
authors.forename: Boh Kyung
authors.initials: BK
authors.lastname: Kim
authors.affiliation: Department of Food Science and Nutrition and Kimchi Research Institute, Pusan National University, 2, Busandaehak-ro 63beon-gil, Geumjeong-gu, Busan 609-735, Korea.
authors.forename: Ji Myung
authors.initials: JM
authors.lastname: Choi
authors.affiliation: Department of Conversing Technology, Graduate School of Venture, Hoseo University, Seoul 137-867, Korea.
authors.forename: Soon Ah
authors.initials: SA
authors.lastname: Kang
authors.affiliation: Department of Food Science and Nutrition and Kimchi Research Institute, Pusan National University, 2, Busandaehak-ro 63beon-gil, Geumjeong-gu, Busan 609-735, Korea.
authors.forename: Kun Young
authors.initials: KY
authors.lastname: Park
authors.affiliation: Department of Food Science and Nutrition and Kimchi Research Institute, Pusan National University, 2, Busandaehak-ro 63beon-gil, Geumjeong-gu, Busan 609-735, Korea.
authors.forename: Eun Ju
authors.initials: EJ
authors.lastname: Cho
keywords: Kimchi; fermentation; free radical; nitrosative stress; oxidative stress