Yun Chang Koo

Mutagenicity and Oral Toxicity Studies of Terminalia chebula

The fruit of Terminalia chebula Retz. (T. chebula), which is a member of the Combfreetaceae family, is used widely in Asian countries as a traditional folk medicine, and its extract has been reported to be an anticancer, antidiabetic and anticaries agent. In our previous study, chebulic acid isolated from T. chebula extract was confirmed to show antioxidant activity and protective action against endothelial cell dysfunction. In order to support the safety‐in‐use of the ethyl acetate (EtOAc)‐soluble portion of a T. chebula ethanol extract containing 29.4% chebulic acid content, the prepared portion was tested in an in vitro mutagenicity assay, and a single‐ and 14‐day repeated dose oral toxicity study. In the bacterial mutation assay, up to 5000u2009µg/mL concentration of the EtOAc‐soluble portion, the numbers of colonies did not increase whether with or without metabolic activation. In the oral toxicity study, the single oral dose of the extract at 2000u2009mg/kg did not produce mortality or abnormal lesions in the internal organs of rats. The results of a 14‐day orally repeated dose showed that the EtOAc‐soluble portion of T. chebula ethanol extracts gave no adverse effects at dosages of 2000u2009mg/kg in rats in the study. Copyright

Antilipogenic and Anti-Inflammatory Activities of Codonopsis lanceolata in Mice Hepatic Tissues after Chronic Ethanol Feeding

This study evaluated the antilipogenic and anti-inflammatory effects of Codonopsis lanceolata (C. lanceolata) root extract in mice with alcohol-induced fatty liver and elucidated its underlying molecular mechanisms. Ethanol was introduced into the liquid diet by mixing it with distilled water at 5% (wt/v), providing 36% of the energy, for nine weeks. Among the three different fractions prepared from the C. lanceolata root, the C. lanceolata methanol extract (CME) exhibited the most remarkable attenuation of alcohol-induced fatty liver with respect to various parameters such as hepatic free fatty acid concentration, body weight loss, and hepatic accumulations of triglyceride and cholesterol. The hepatic gene and protein expression levels were analysed via RT-PCR and Western blotting, respectively. CME feeding significantly restored the ethanol-induced downregulation of the adiponectin receptor (adipoR) 1 and of adipoR2, along with their downstream molecules. Furthermore, the study data showed that CME feeding dramatically reversed ethanol-induced hepatic upregulation of toll-like receptor- (TLR-) mediated signaling cascade molecules. These results indicate that the beneficial effects of CME against alcoholic fatty livers of mice appear to be with adenosine- and adiponectin-mediated regulation of hepatic steatosis and TLR-mediated modulation of hepatic proinflammatory responses.

Chebulic acid prevents hepatic fibrosis induced by advanced glycation end-products in LX-2 cell by modulating Nrf2 translocation via ERK pathway

Advanced glycation end-products (AGEs) are formed during normal aging, and at an accelerated rate in metabolic syndrome patients. Nonalcoholic steatohepatitis (NASH) can be caused by the AGEs in plasma, while glyceraldehyde-derived AGEs (glycer-AGEs) are significantly higher in the serum of NASH patients. In this study, we investigated the molecular mechanisms of chebulic acid, isolated from Terminalia chebula Retz., in the inhibition of glycer-AGEs induced production of reactive oxygen species (ROS) and collagen accumulation using the LX-2 cell line. Chebulic acid significantly inhibited the induction of ROS and accumulation of collagen proteins by glycer-AGEs. ERK phosphorylation and total nuclear factor E2-related factor 2 (Nrf2) protein expression were induced by chebulic acid in a dose-dependent manner. Chebulic acid was also found to induce translocation of Nrf2 into the nucleus, which was attenuated by inhibition of ERK phosphorylation through treatment with PD98059. Following translocation of Nrf2, chebulic acid induced the protein expressions of catalytic subunit of γ-glutamylcysteine synthetase and glutathione synthesis. Collagen accumulation was also significantly reduced by chebulic acid treatment. The observed effects of chebulic acid were all inhibited by PD98059 treatment. Taken together, these results suggest that chebulic acid prevents the glycer-AGEs-induced ROS formation of LX-2 cells and collagen accumulation by ERK-phosphorylation-mediated Nrf2 nuclear translocation, which causes upregulation of antioxidant protein production.

Caffeic Acid Inhibits the Uptake of 2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) by Inducing the Efflux Transporters Expression in Caco-2 Cells

2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is formed as a by-product of the Maillard reaction during cooking and frying of protein-rich foods at high temperatures. PhIP is metabolized in the liver by cytochrome P450 1A1/2 to carcinogenic metabolite N-hydroxy PhIP, which can form DNA adduct. The ATP binding cassette (ABC) transporters, P-glycoprotein (P-gp), multidrug resistance-associated protein 2 (MRP2) and breast cancer resistance protein (BCRP) are capable of transporting the food-borne procarcinogen PhIP back to the intestinal lumen. In the present study, the uptake and efflux of PhIP were assessed by determining apparent bidirectional permeability coefficients and efflux ratio. The efflux ratio of PhIP with 10 µM caffeic acid was significantly increased compared with control. The mRNA levels of efflux transporters were measured to evaluate the effect of caffeic acid in the presence of PhIP on efflux-mediated transport of PhIP. Caco-2 cells exposed to 10 µM caffeic acid for 3 and 6 h also exhibited higher mRNA levels of P-gp and BCRP than those of control. In contrast, the mRNA level of MRP2 was only slightly induced after 3 h and 6 h. Therefore, caffeic acid at low concentration is expected to be used not only as an antioxidant, but also as an inhibitor of the absorption of food borne carcinogen heterocyclic amines. However, further studies, especially in vivo studies, are required to confirm these results.

Immune enhancing effect of a Maillard-type lysozyme-galactomannan conjugate via signaling pathways.

We studied the immune-modulating effect of Maillard-type lysozyme-galactomannan conjugate (LGC). LGC significantly induced nitric oxide, and expressions of tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-8 on the murine macrophage Raw 264.7 cell line. In the mechanism of LGC, while extracellular signal-regulated kinase (ERK) was important for the induction of TNF-α, IL-1β and IL-8, the phosphorylation of C-Jun NH2-termianl kinase (JNK) contributed to the induction of TNF-α and IL-1β to a greater degree. These cytokines were less sensitive to the inhibition of p38. Nuclear factor (NF)-κB was involved in the induction of TNF-α and IL-1β. These data indicate that LGC has immune-modulating effects via JNK, ERK and NF-κB pathways, and that LGC may contribute to host immune defense.

In vivo study of the renal protective effects of Capsosiphon fulvescens against streptozotocin-induced oxidative stress

Mi-Hyun Nam, Yun-Chang Koo, Chung-Oui Hong, Sung-Yong Yang, Se-Wook Kim, Hye-Lim Jung, Hwa Lee, Ji-Yeon Kim, Ah-Ram Han, Won-rak Son, Min-Cheol Pyo, and Kwang-Won Lee*Division of Food Bioscience and Technology, College of Life Science & Biotechnology, Korea UniversityAbstract In this study, we evaluated the effect of Capsosiphon fulvescens extract (CFE) and its active compound,pheophorbide A (PhA), on diabetic kidney failure. Diabetes mellitus (DM) was induced by a single intraperitoneal injectionof streptozotocin (STZ; 40 mg/kg body weight (BW)). After a week, the rats were orally administered CFE (4 and 20 mg/kg BW) or PhA (0.2 mg/kg BW) once a day for 9 weeks. After scarification, renal tissue samples were collected forbiochemical and histochemical analyses. Our study showed that the treatment with CFE and PhA significantly decreasedlipid peroxidation level and the activities of glutathione peroxidase and glutathione-S-transferase (p<0.05), but it increasedglutathione level and the activities of glutathione reductase, superoxide dismutase, and catalase in the renal tissues(p<0.05). The CFE- and PhA-treated rats with DM showed improved histochemical appearance and decreased abnormalglycogen accumulation. Therefore, we suggest that PhA-containing CFE could exert renal protective effects against STZ-induced oxidative stress.Keywords: Capsosiphon fulvescens , streptozotocin, diabetic rats, oxidative stress, antioxidant enzyme, renal protective effects

Cytogenetic investigation of chromosomal aberrations in cells treated with plantamajoside from Plantago asiatica.

Plantago asiatica is a member of the Plantaginaceae family, and is widely distributed in East Asia. In our previous work, a single active compound, plantamajoside was isolated and confirmed to have glycation inhibitory activity, and did not possess toxicity during a 90 day repeated oral toxicity test in rats. In the present study, a chromosomal aberration test was performed to investigate the genotoxicity of plantamajoside. From the results of the cytotoxicity test, plantamajoside proved to be less toxic when it was treated combined with S9 cell fractions. However, there was a significant increase in structural aberrations during the short‐term treatment of plantamajoside at its highest dose (5000 µg/mL) even when combined with S9. This seems to have been a natural phenomenon due to the very high dose of plantamajoside that was used. However, to confirm the safety of plantamajoside for its potential use as a phytochemical agent in health products, additional mutagenicity tests are necessary. Copyright

Inhibitory Effect of Yellow Myrobalan (Terminalia chebula) Extract on Fibrosis Induced by Carbon Tetrachloride in Rat Liver

Ethyl acetate layer of methanol extract (TCE) of yellow myrobalan (Terminalia chebula) contains 2.4% of chebulic acid, a standard compound in TCE, which have a strong anti-oxidative effect and was reported in our previous study. Thirty-one male SD rats were randomly divided into 5 groups (normal control, CCl4 control, TCE control, CCl4+high dose TCE, and low dose TCE). Liver fibrosis was induced by i.p. injection of CCl4 and TCE were orally administrated. TCE decreased the up-regulated malondealdehyde value and increased the down-regulated ratio of GSH/GSSG content and activities of GRd, GPx, and GST compared to the CCl4 control group. Decreased dysfunction and inflammatory reaction in liver was confirmed by alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, relative liver weight and infiltration of neutrophils. Also, TCE inhibited phenotype change of hepatic stellate cells (HSC) by reducing α-smooth muscle actin (α-SMA) gene expression and protein production. Inhibition of collagen 1A1 gene expression and protein production were also confirmed. From these results, TCE may be a useful material for preventing liver fibrosis.

Development of Method for Analysis of Four Sulfonylurea Pesticides, Rimsulfuron, Ethametsulfuron-methyl, Tribenuron-methyl, Chlorimuron-ethyl Residues by High-Performance Liquid Chromatography with Diode-Array Detection

The method for residue analysis of four sulfonylurea pesticides, rimsulfuron, ethametsulfuron-methyl, tribenuron-methyl and chlorimuron-ethyl was examined and analyzed by HPLC with ODS column (250 ㎜×4.6 ㎜, 5 ㎛ diameter particle size) which was maintained at 35oC. Mobile phase consisted of solvent A (20 mM KH₂PO₄, pH 2.5) and solvent B (acetonitrile). Isocratic elution of the column with 45% solvent A and 55% solvent B at a flow rate of 1 mL/min resulted in retention times of 5.92, 6.54, 9.28, and 14.35 min for rimsulfuron, ethametsulfuron-methyl, tribenuron-methyl, and chlorimuron-ethyl, respectively. All injection volumes were 20 μL. The limit of quantitation was 0.02, 0.01, 0.001, and 0.004 ㎎/㎏ for rimsulfuron, ethametsulfuron-methyl, tribenuron-methyl, and chlorimuron-ethyl, respectively. Recovery rate test was performed with three farm products, rice, apple and soybean. Four sulfonylurea pesticides were spiked at concentrations of 0.05, 0.1 and 0.5 ㎎/㎏. The recovery rates were ranged from 86.12% to 116.26% and the standard deviations of all experiments were within 10%.