Hee-Sook Sohn

Stimulation of melanogenesis by scoparone in B16 melanoma cells

AbstractAim:The effect of coumarin derivatives on melanogenesis was investigated in B16 murine melanoma cells.Methods:Melanin content and tyrosinase activity were analyzed spectrophotometrically. The expression of tyrosinase, tyrosinase-related protein-1 (TRP-1) and tyrosinase-related protein-2 (TRP-2) were measured either by reverse transcription-polymerase chain reaction (RT-PCR) or Western blot.Results:Among the coumarin derivatives studied, scoparone (6,7-dimethoxycoumarin) was the most potent; the 6- or 7-methoxy group was found to be essential for the stimulation of melanogenesis. The melanin content was greatly increased by scoparone in a dose-dependent manner; there was no cytotoxicity at the effective concentrations. Scoparone increased enzyme activity as well as protein and mRNA expression of tyrosinase. In addition, mRNA of TRP-1 and TRP-2 were also increased after treatment with scoparone. H-89, an inhibitor of protein kinase A (PKA), completely inhibited the scoparone-induced increase of melanogenesis and the tyrosinase protein.Conclusion:These results suggest that scoparone-induced stimulation of melanogenesis is likely to occur at the transcriptional level of melanogenesis-related enzymes through PKA signaling.

Intracellular lipid accumulation inhibitory effect of Weissella koreensis OK1‐6 isolated from Kimchi on differentiating adipocyte

To investigate the intracellular lipid accumulation inhibitory effect of spent culture medium extract and the cytoplasmic fraction of Weissella koreensis OK1‐6 cells isolated from kimchi in differentiating 3T3‐L1 cells.

Cytotoxic mechanism of Vibrio vulnificus cytolysin in CPAE cells.

Vibrio vulnificus is an estuarian bacterium that causes septicemia and serious wound infection. The cytolysin, one of the important virulence determinants in V. vulnificus infection, has been reported to have lethal activity primarily by increasing pulmonary vascular permeability. In the present study, we investigated the cytotoxic mechanism of V. vulnificus cytolysin in cultured pulmonary artery endothelial (CPAE) cells, which are possible target cells of cytolysin in vivo. V. vulnificus cytolysin caused the CPAE cell damages with elevation of the cytosolic free Ca2+, DNA fragmentation, and decrease of the cellular NAD+ and ATP level. These cytotoxic effects of V. vulnificus cytolysin were prevented by EGTA and aminobenzamide, but were not affected by verapamil or catalase. These results indicate that the elevation of cytosolic free Ca2+ induced by V. vulnificus cytolysin causes the increase of DNA fragmentation and the damaged DNA activates nuclear poly(ADP-ribose) synthetase, which depletes the cellular NAD+ and ATP, resulting in cell death.

Retinoic acid inhibits inducible nitric oxide synthase expression in 3T3-L1 adipocytes

The present study was undertaken to explore whether retinoids, which are known to have immunomodulatory actions, could attenuate tumor necrosis factor-α (TNF)-stimulated inducible nitric oxide synthase (iNOS) expression in 3T3-L1 adipocytes. Adipocytes incubated with TNF induced dose- and time-dependent accumulation of nitrite in the culture medium through the iNOS induction as confirmed by Western blotting. Treatment of cells with TNF in the presence of all-trans-retinoic acid (RA) significantly decreased their ability to produce nitrite and iNOS induction. Both 13-cis- and all- trans-RA-induced suppression was dose-dependent, and all-trans-RA was somewhat potent than 13-cis-RA. The inhibitory effect of RA on TNF-induced iNOS induction was reversible, completely recovered after 2 days, and was exerted through the inhibition of NF-κB activation. TNF also suppressed the lipoprotein lipase (LPL) activity of 3T3-L1 adipocytes. RA could not reverse the TNF- induced LPL suppression at RA levels causing near complete inhibition of the TNF-induced NO production. These results indicate that RAs attenuate iNOS expression reversibly in TNF-stimulated 3T3-L1 adipocytes, and that the TNF- induced LPL suppression is not the result of NO overproduction.

Effects of Nutrition Education on Overweight and Obese Children in Chonbuk Area -Focus on Food Habit, Eating Behaviors, Dietary Attitude, Nutrition Knowledge and Nutrients Intake-

The purpose of this study was to investigate the effects of nutrition education focus on food habit, eating behaviors, dietary attitude, nutrition knowledge, and nutrients intake. The nutrition education was provided to 103 overweight and obese children in Chonbuk area. Nutrition education lessons were conducted 40 min/lesson, 12 times in year (6 times/semester). We assessed the change in knowledge using a questionnaire on food habit, eating behaviors, dietary attitude, nutrition knowledge and nutrients intake using 24 hr recall method. After the nutrition education, dietary habits were significantly improved. Especially, the answer of `Don`t eat when feel full` were significantly improved (boys (p

Effects of exercise training and/or high fat diet on lipid metabolism and carnitine concentrations in rats

The effect of high fat diet and/or exercise on lipid metabolism and carnitine status was investigated in young Sprague-Dawley rats. The rats were fed an AIN-76 diet or a modified high-fat AIN-76 diet, supplemented with 20% corn oil, for 30 days. During the 30-day period half of the animals in each dietary group were exercised on a treadmill for 90 minutes per day. Lipid concentrations in both plasma and liver were determined, and carnitine concentrations were determined in plasma, liver, kidney, heart, and skeletal muscle. Exercised rats gained less weight than non-exercised rats during the study (135.7g vs. 119.4g and 134g vs. 119.1g for normal and high-fat diets groups, respectively). Plasma cholesterols, and liver triacylglycerol were significantly lower in exercised than non-exercised rats on either diet. Liver total lipids were lower in exercised rats but higher in rats fed the high fat diet. In liver tissue, carnitine concentrations were primarily increased by high fat diet. However, in kidney and skeletal muscle exercise resulted in higher concentrations of non-esterified, acyl, and total carnitine. High fat diet in skeletal muscle caused an increase in acyl and decrease in free carnitine concentrations without effecting total carnitine. This research demonstrates that, in rats, exercise is more important in reducing body weight gain than the fat content of the diet, and demonstrates a beneficial effect of exercise and detrimental effect of high fat diet on blood lipid parameters. This study also demonstrates that both high fat diet and exercise can increase tissue carnitine concentrations in an organ specific manner.

Effects of Irradiation Temperature on the Sensory Quality Improvement of Gamma-irradiated Ganjang-gejang, Korean Traditional Marinated Raw Crab Portunus trituberculatus in Soybean Sauce

This study was conducted to confirm quality properties of sterilized Ganjang-gejang (marinated crab Portunus trituberculatus) with Korean soy sauce using by gamma irradiation and to improve quality of sterilized Ganjang-gejang. The Ganjang-gejang was irradiated at dose of 3, 6, 9, 12, and 15 kGy by gamma irradiation and there was evaluated in microbiological, physicochemical, and sensory properties. Total aerobic bacteria and fungi contents of non-irradiated samples were about 6 and 4 log CFU/g level, respectively. Gamma-irradiated samples at above 9 kGy did not contain aerobic bacteria or fungi at detection limit less than 2 log CFU/g, but sensory scores were significantly decreased depending on the irradiation dose. To improve the sensory qualities of gamma-irradiated Ganjang-gejang, the temperature was adjusted during sample irradiation. When samples were irradiated under freezing temperatures, especially on dry ice, the TBARS and the deterioration of sensory qualities of Ganjan-Gejang were reduced. Different odor patterns were observed among samples, as observed using electronic nose analysis system. The results of this study indicated that treatment with irradiation under low temperatures may help to preparing high-quality Ganjang-gejang.

Antihypertensive effect of Ganjang (traditional Korean soy sauce) on Sprague-Dawley Rats

BACKGROUND/OBJECTIVES Although Korean fermented foods contain large amounts of salt, which is known to exacerbate health problems, these foods still have beneficial effects such as anti-hypertension, anti-cancer, and anti-colitis properties. We hypothesized that ganjang may have different effects on blood pressure compared to same concentrations of salt. MATERIALS/METHODS Sprague-Dawley rats were divided into control (CT), NaCl (NC), and ganjang (GJ) groups and orally administered with 8% NaCl concentration for 9 weeks. The systolic blood pressure (SBP), serum chemistry, Na+ and K+ concentrations and renal gene expressions were measured. RESULTS The SBP was significantly increased in the NC group compared to the GJ and CT groups. In addition, the Na+ concentration in urine was higher in the GJ and NC groups than the CT group, but the urine volume was increased in the GJ group compared to the other groups. The serum renin levels were decreased in the GJ group compared to the CT group, while the serum aldosterone level was decreased in the GJ group relative to the NC group. The mRNA expression of the renin, angiotensin II type I receptor, and mineralocorticoid receptor were significantly lower in the GJ group compared to other groups. Furthermore, GJ group showed the lowest levels of genes for Na+ transporter in kidney cortex such as Na+/K+ ATPaseα1 (NKAα1), Na+/H+ exchanger 3 (NHE3), Na+/HCO3- co-exchanger (NBC), and carbonic anhydrases II (CAII). CONCLUSIONS The decreased SBP in the GJ could be due to decreased renin and aldosterone levels in serum and increased urinary volume and excretion of Na+ with its transporter gene alteration. Therefore, ganjang may have antihypertensive effect despite its high contents of salt.

Hypocholesterolemic effect of quercetin-rich onion peel extract in C57BL/6J mice fed with high cholesterol diet

Onion peel (OP) extract is known as a rich source of flavonoids, mainly quercetin. We hypothesized that OP has hypocholesterolemic effects. To investigate the effect of OP, C57BL/6J mice were divided into 4 dietary groups (n=10); normal diet (ND); high cholesterol diet (HC); and high cholesterol diet with 100 or 200 mg OP extract (OP-100 or OP-200, respectively) per kg of body weight. After 12 weeks, lower values of liver weight, serum total cholesterol levels, LDL cholesterol, atherogenic index, cardiac risk factor, hepatic triacylglycerol, and total cholesterol, and higher fecal cholesterol levels were observed in the OP-200 than in the HC group. The hepatic mRNA expression levels of low-density lipoprotein receptors (LDL-R) and cholesterol 7-alpha-monooxygenase (CYP7A1) were high in the OP-200 compared to the HC group. These observations suggest that OP promoted lowering of serum and hepatic cholesterol in mice primarily via fecal excretion.