Antioxidative effects of Kimchi under different fermentation stage on radical-induced oxidative stress.

BACKGROUND/OBJECTIVES: 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. MATERIALS/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. CONCLUSION: 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.

Protective effects of Korean mistletoe lectin on radical-induced oxidative stress.

The radical scavenging effects and protective activities against oxidative stress of Korean mistletoe (Viscum album coloratum) lectin were investigated in vitro and with a cellular system using LLC-PK(1) renal epithelial cells. The Korean mistletoe lectin (KML) showed 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity with an IC(50) value of 42.6 microg/ml. It also exerted nitric oxide (NO), superoxide anion (O(2)(-)), and hydroxyl radical scavenging activities in concentration-dependent manners. These results suggest that KML is a promising antioxidant by scavenging free radicals. Furthermore, under the LLC-PK(1) cellular model, the cells showed declines in viability and increases in lipid peroxidation through oxidative stress induced by sodium nitroprusside (SNP) and pyrogallol, generators of NO and O(2)(-), respectively. However, KML significantly and dose-dependently inhibited cell cytotoxicity and lipid peroxidation. In addition, 3-morpholinosydnonimnie (SIN-1), a generator of peroxynitrite (ONOO(-)) formed by simultaneously releases of NO and O(2)(-), caused cytotoxicity, lipid peroxidation, and NO overproduction in the LLC-PK(1) cells while KML ameliorated ONOO(-)-induced oxidative damage. Furthermore, overexpressions of cyclooxygenase-2 and inducible NO synthase induced by SIN-1 were observed, but KML down-regulated the expression levels of both genes. KML also reduced SIN-1-induced nuclear factor kappa B expression and the phosphorylation of inhibitor kappa B alpha in LLC-PK(1) cells. These results indicate that KML has protective activities against oxidative damage induced by free radicals.

Anti-aging effects of cyanidin under a stress-induced premature senescence cellular system.

The anti-aging effects of cyanidin were investigated under stress-induced premature senescence (SIPS) using WI-38 human diploid fibroblasts. WI-38 cells that were treated with 300 microM H(2)O(2) showed losses of cell viability, increased lipid peroxidation, and shortened cell lifespans. However, treatment with cyanidin attenuated cellular oxidative stress through increase of cell viability and the inhibition of lipid peroxidation. In addition, the life spans of young-, middle-, and old-aged WI-38 cells were prolonged by cyanidin treatment. Furthermore, H(2)O(2)-treated WI-38 cells significantly increased mRNA and protein expressions of nuclear factor-kappaB, cyclooxygenase-2, and inducible nitric oxide synthase, while those treated with cyanidin had significantly decreased expressions. These results suggest that cyanidin may delay the aging process by attenuating oxidative stress under the SIPS cellular model.

Antiproliferative effect of chitosan-added kimchi in HT-29 human colon carcinoma cells.

The anticancer effects of chitosan-added kimchi were investigated by using an in vitro cellular system with HT-29 human colon carcinoma cells. Two different kinds of chitosan-soluble chitosan with a 90% degree of deacetylation and 3 cps viscosity and nonsoluble chitosan with a 95% degree of deacetylation and 22 cps viscosity-were used as sub-ingredients to increase anticancer effects of kimchi. The soluble chitosan-added kimchi (SK) and nonsoluble chitosan-added kimchi (NK) were stronger growth inhibitors in HT-29 cells than the control kimchi (CK) according to the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and the growth inhibition test. Treatment with SK and NK induced apoptosis, as determined by 4,6-diamidino-2-phenylindole staining, and resulted in the up-regulation of Bax expression and down-regulation of Bcl-2, cIAP-1, cellular inhibitor of apoptosis-2, cyclooxygenase-2, inhibitory nitric oxide synthase, and nuclear factor kappaB (NF-kappaB) expressions when compared to CK. The antiproliferative and anti-apoptotic effects appeared to be more pronounced in the cells treated with NK. The antiproliferative effects of the chitosan-added kimchi appeared to be associated with the induction of apoptosis through NF-kappaB or an NF-kappaB-dependent pathway. These results suggest that chitosan has potential to be a valuable active ingredient in functional kimchi products with anticancer effects.