Ji Myung Choi

Protective role of caffeic acid in an Aβ25-35-induced Alzheimer's disease model

BACKGROUND/OBJECTIVES Alzheimers disease (AD) is characterized by deficits in memory and cognitive functions. The accumulation of amyloid beta peptide (Aβ) and oxidative stress in the brain are the most common causes of AD. MATERIALS/METHODS Caffeic acid (CA) is an active phenolic compound that has a variety of pharmacological actions. We studied the protective abilities of CA in an Aβ25-35-injected AD mouse model. CA was administered at an oral dose of 10 or 50 mg/kg/day for 2 weeks. Behavioral tests including T-maze, object recognition, and Morris water maze were carried out to assess cognitive abilities. In addition, lipid peroxidation and nitric oxide (NO) production in the brain were measured to investigate the protective effect of CA in oxidative stress. RESULTS In the T-maze and object recognition tests, novel route awareness and novel object recognition were improved by oral administration of CA compared with the Aβ25-35-injected control group. These results indicate that administration of CA improved spatial cognitive and memory functions. The Morris water maze test showed that memory function was enhanced by administration of CA. In addition, CA inhibited lipid peroxidation and NO formation in the liver, kidney, and brain compared with the Aβ25-35-injected control group. In particular, CA 50 mg/kg/day showed the stronger protective effect from cognitive impairment than CA 10 mg/kg/day. CONCLUSIONS The present results suggest that CA improves Aβ25-35-induced memory deficits and cognitive impairment through inhibition of lipid peroxidation and NO production.

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.

Identification of anti-cancer active components of Taraxacum coreanum on human gastric cancer AGS cells

Anti-cancer effects were compared amongst Taraxacum coreanum extract, its fractions, and 7 ingredients (β-sitosterol, daucosterol, taraxasteryl acetate, chrysoeriol, diosmetin, luteolin, and luteoloside). Exposure to the ethyl acetate fraction (50 and 100 μg/mL) of T. coreanum extract and luteolin (10 and 50 μM) for 24 h induced the cleavage of poly (ADP-ribose) polymerase (PARP), caspase-3, and caspase-8, in a dose-dependent manner. These findings demonstrate that luteolin is the main active component of T. coreanum extract activating caspases-3 and -8 which contribute to apoptotic cell death.

Protective role of oligonol from oxidative stress-induced inflammation in C6 glial cell

BACKGROUND/OBJECTIVES Natural products or active components with a protective effect against oxidative stress have attracted significant attention for prevention and treatment of degenerative disease. Oligonol is a low molecular weight polyphenol containing catechin-type monomers and oligomers derived from Litchi chinensis Sonn. We investigated the protective effect and its related mechanism of oligonol against oxidative stress. MATERIALS/METHODS Oxidative stress in C6 glial cells was induced by hydrogen peroxide (H2O2) and the protective effects of oligonol on cell viability, nitric oxide (NO) and reactive oxygen species (ROS) synthesis, and mRNA expression related to oxidative stress were determined. RESULTS Treatment with oligonol inhibited NO and ROS formation under cellular oxidative stress in C6 glial cells. In addition, it recovered cell viability in a dose dependent-manner. Treatment with oligonol also resulted in down-regulated mRNA expression related to oxidative stress, nuclear factor kappa-B (NF-κB) p65, cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS), compared with the control group treated with H2O2. In particular, expression of NF-κB p65, COX-2, and iNOS was effectively reduced to the normal level by treatment with 10 µg/mL and 25 µg/mL of oligonol. CONCLUSIONS These results indicate that oligonol has protective activity against oxidative stress-induced inflammation. Oligonol might be a promising agent for treatment of degenerative diseases through inhibition of ROS formation and NF-κB pathway gene expression.

Antibacterial activity and protective effect against gastric cancer by Anthriscus sylvestris fractions

The aim of this research was to investigate the industrial application of Anthriscus sylvestris. Antibacterial activities of the n-hexane, methylene chloride (MC), ethyl acetate, and butanol fractions of A. sylvestris were tested against Escherichia coli, Staphylococcus aureus, and Helicobacter pylori. The n-hexane and MC fractions showed a stronger antibacterial activity against S. aureus than other fractions, with an inhibition zone greater than 11 mm in disc assays. At 100 μg·mL−1, all fractions extracted from A. sylvestris scavenged more than 85% of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radicals (·OH); however, the n-hexane and MC fractions showed the strongest scavenging activity of DPPH and ·OH. In addition, we found that treatment with the n-hexane and MC fractions inhibited the growth of H. pylori and gastric adenocarcinoma cells. Further testing of falcarindiol and deoxypodophyllotoxin from the MC fraction of A. sylvestris revealed the antibacterial effects against E. coli, S. aureus, and H. pylori, suggesting their potential use as antibacterial agents.