Jae-Young Cha

Effects of conjugated linoleic acid on serum leptin concentration, body-fat accumulation, and β-oxidation of fatty acid in OLETF rats

We investigated the efficacy of a 4-wk supplementation of conjugated linoleic acid (CLA) as free fatty acid (FFA) or triacylglycerol (TG) on serum leptin concentration, body-fat accumulation, and mitochondrial beta-oxidation in Otsuka Long-Evans Tokushima Fatty (OLETF) rats. A significant reduction of serum leptin concentration (42%) and a decrease in the wet weights of perirenal, epididymal, and omental/visceral-adipose tissue in TG-CLA and FFA-CLA groups were found in comparison with the OLETF control group. Both forms of CLA supplementation produced a 5.2% decrease in body weight compared with the control even though food intake was similar in the OLETF groups. Moreover, both forms of CLA enhanced carnitine-palmitoyltransferase activity in brown adipose tissue, perirenal adipose tissue, red gastrocnemius muscle, and liver in comparison with the OLETF control group. Serum concentrations of non-esterified fatty acid and TG also were reduced in rats fed diets supplemented with TG-CLA and FFA-CLA.

Dietary effect of pomegranate seed oil rich in 9cis, 11trans, 13cis conjugated linolenic acid on lipid metabolism in obese, hyperlipidemic OLETF Rats

Conjugated fatty acid, the general term of positional and geometric isomers of polyunsaturated fatty acids with conjugated double bonds, has attracted considerable attention because of its potentially beneficial biological effects. In the present study, dietary effect of pomegranate seed oil rich in punicic acid (9cis, 11trans, 13cis-conjugated linolenic acid; 9c, 11t, 13c-CLNA) on lipid metabolism was investigated in obese, hyperlipidemic Otsuka Long-Evans Tokushima Fatty (OLETF) rats. After 2 weeks feeding period, OLETF rats revealed obesity and hyperlipidemia compared with their progenitor LETO rats. Feeding of the diet supplemented with 9% safflower oil and 1% pomegranate seed oil (9c, 11t, 13c-CLNA diet) did not affect abdominal white adipose tissue weights and serum lipid levels compared with the diet supplemented with 10% safflower oil (control diet) in OLETF rats. However, the accumulated hepatic triacylglycerol was markedly decreased by 9c, 11t, 13c-CLNA diet in OLETF rats. Activities of hepatic enzymes related to fatty acid synthesis and fatty acid β-oxidation were not altered by 9c, 11t, 13c-CLNA diet. Levels of monounsaturated fatty acid (MUFA), major storage form of fatty acid, in serum triacylglycerol were markedly higher in obese, hyperlipidemic OLETF rats than in lean LETO rats. In addition, 9c, 11t, 13c-CLNA diet significantly decreased MUFA levels in OLETF rats. This is the first study showing that 9c, 11t, 13c-CLNA suppresses delta-9 desaturation in vivo, and we suggest that the alleviation of hepatic triacylglycerol accumulation by 9c, 11t, 13c-CLNA diet was, at least in part, attributable to the suppression of delta-9 desaturation in OLETF rats.

Effects of short-term administration of conjugated linoleic acid on lipid metabolism in white and brown adipose tissues of starved/refed Otsuka Long-Evans Tokushima Fatty rats

The present study explored the short-term effects of dietary conjugated linoleic acid (CLA) on body fat accumulation and lipid metabolism in starved/refed Otsuka Long-Evans Tokushima Fatty (OLETF) rats. Male OLETF rats of 12-weeks-old were starved for 24 h and then re-fed for 48 h either with CLA diet [7.5% CLA and 7.5% safflower oil (SAF)] or SAF control diet (15% SAF oil). The results demonstrated a 27% reduction of white adipose tissue wet weight (total of epididymal and perirenal adipose tissue weight) in the CLA group compared to the control group. The activity of mitochondrial carnitine palmitoyltransferase (CPT), the rate-limiting enzyme for fatty acid oxidation, was significantly elevated by 1.7- and 1.6-fold in perirenal white adipose tissue and interscapular brown adipose tissues, respectively, in the CLA group compared to the control. In contrast, phosphatidate phosphohydrolase (PAP), the rate-limiting enzyme for triglyceride (TG) synthesis, was found to be 23 and 15% lower, in perirenal white- and brown- adipose tissue of CLA-fed rats, respectively. In addition, CLA feeding led to a significant reduced concentration of serum total- and HDL-cholesterol and phospholipid. Thus, dietary CLA evidently lowers abdominal white adipose tissue wet weight through an enhanced fatty acid oxidation and a reduced TG synthesis.

Antioxidant effects of fermented sea tangle (Laminaria japonica) by Lactobacillus brevis BJ20 in individuals with high level of γ-GT: A randomized, double-blind, and placebo-controlled clinical study

A randomized, double-blind, and placebo-controlled clinical study was performed to evaluate the antioxidant effects of fermented sea tangle (FST) on healthy volunteers with high levels of γ-glutamyltransferse (γ-GT). Forty-eight participants were divided into a placebo group and an FST group that received FST (1.5 g/day) for 4 weeks. Serum γ-GT, malondialdehyde (MDA), catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) activities were determined before and after the trial. Administering FST significantly decreased serum levels of γ-GT and MDA. Additionally, SOD and CAT activities were significantly augmented compared to those in the placebo group after 4 weeks, but no significant alteration was observed in GPx activity compared to that in the placebo group. Our findings indicate that FST enhanced the antioxidant defense system in a healthy population and may be useful as a functional food ingredient.

Protective effect of cordycepin-enriched Cordyceps militaris on alcoholic hepatotoxicity in Sprague–Dawley rats

This study was to investigate the protective effect of cordycepin-enriched Cordyceps militaris against alcohol-induced hepatotoxicity in Sprague-Dawley rats. Alcohol-feeding rats were fed diets with Paecilomyces japonica as CPJ group, C. militaris as CCM group, cordycepin-enriched C. militaris as CCMα group at the 3% (w/w) level and silymarin at the 0.1% (w/w) level for 4 weeks. Alcohol administration resulted in a significant increase in the activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), γ-glutamyl transpeptidase (γ-GTP), alkaline phosphatase (ALP), and lactate dehydrogenase (LDH) and the levels of blood alcohol and acetaldehyde in serum. However, CCMα group markedly prevented from alcohol-induced elevation of these parameters in serum. CCMα group showed the increased both hepatic activities of alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase (ALDH). Unlike the action of alcohol treatment on alcoholic fatty liver, CCMα group was also attenuated lipid droplet accumulation in the hepatocytes. Present study was also confirmed the beneficial roles of silymarin (hepatoprotective agent) against alcohol-induced liver injury in rats. Therefore, cordycepin-enriched C. militaris can be a promising candidate to prevent from alcohol-induced hepatotoxicity.

NK-104, A Potent New 3-Hydroxy-3-Methylglutaryl Coenzyme A Reductase Inhibitor, Enhances Posttranslational Catabolism of Apolipoprotein B-100 and Inhibits Secretion of Apolipoprotein B-100 and Triacylglycerols from HepG2 Cells

Abstract The effects of NK-104, a new, potent 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, on the secretion and intracellular catabolism of apolipoprotein B-100 (apo) and on lipid metabolism in HepG2 cells were investigated. The cells were treated with NK-104 1 or 10 uM for 3 or 24 hours in 1% bovine serum albumin-containing medium. To examine intracellular apo B catabolism, the cells were labeled with 85 S-methionine for 10 minutes and followed for up to 90 minutes. NK-104 reduced the secretion of apo B and 35 S-labeled apo B. The degradation rate of intracellular 35 S-labeled apo B was faster in cells treated with NK-104 than in controls, suggesting that apo B stability was decreased by treatment with NK-104. NK-104 reduced significantly the intracellular levels and synthesis of cholesterol and cholesteryl ester in HepG2 cells. The agent reduced the secretion of labeled triacylglycerols without affecting intracellular triacylglycerol synthesis. Results of this study suggest that NK-104 reduced the secretion of apo B by enhancing degradation of the protein. This effect may be mediated through changes in the intracellular metabolism of cholesterol or cholesteryl ester.

Biological Activity of Fermented Silkworm Powder

The comparative effects of the fibrinolytic, and tyrosinase inhibition activities and electrophoretical protein patterns with freeze-drying silkworm powder (FDSW), heating-drying silkworm powder (HDSW) and fermented silkworm powder by Bacillus subtilis or Lactobacillus hilgardii were investigated. When total protein patterns of FDSW, HDSW, both fermented SW, were analyzed by native- and SDS-polyacrylamide gel electrophoresis (PAGE), there were slightly varietal differences in electrophoretical protein patterns. Major minerals of FDSW and HDSW were K, Ca, Mg, and Zn. Major compositional amino acids of FDSW and HDSW were glycine, alanine, glutamic acid, aspartic acid, and serine. Major fatty acids of FDSW and HDSW were linolenic acid, oleic acid, and palmitic acid. Fibriolytic activity was the highest in the fermented FDSW by 5% B. subtilis among the various samples. Tyrosinase inhibition activity was higher in the water and 70% methanolic extract of FDSW than in HDSW. DPPH radical scavenging activity was slightly stronger in HDSW than in FDSW. In addition, DPPH radical scavenging activity was higher in FDSW or HDSW fermented by L. hilgardii than that fermented by B. subtilis, however, all samples exhibited a relatively low activity compared to the butylated hydroxytoluene (BHT). These results may provide the basic data to understand the biological activities of fermented SW.

Effects of Amino Acids on the Activities of Alcohol Metabolizing Enzyme Alcohol Dehydrogenase (ADH) and Acetaldehyde Dehydrogenase (ALDH)

The present study examined the comparative effects of various amino acids on the alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase (ALDH) activities of yeast Saccharomyces cereviciae and rat liver homogenate in vitro. Methionine showed the highest activity in yeast ADH among the amino acids used in this study, but this was not higher than that of the hangover product, Condition-Power (CP) used as positive control. Methionine was also found to be the best amino acid in terms of the ALDH activity in rat liver homogenate among the treatment amino acids, which was comparatively higher than that of positive control CP. It was chosen for further experiments and yeast ADH activity increased in parallel with increased methionine concentration, but not rat liver ALDH activity, and it was comparatively higher than those of the positive control. Arginine showed the highest values in yeast ALDH and rat liver ADH activities among amino acids, and it was chosen for further experiments. Yeast ALDH activity increased in parallel with increased arginine concentration, which was higher than that of positive control CP, and rat liver ADH activity was also comparatively higher in all treatment concentrations of arginine than that of positive control CP. The native electrophoresis of ADH and ALDH from cell-free extracts of yeast Saccharomyces cerevisiae cultured in the growth medium containing various arginine concentrations by showed two active bands upon zymogram staining analysis, and the straining intensity of ADH and ALDH active bands in arginine treatment yeast was stronger than that of non-yeast or low treatment yeast. These results indicate that alcohol metabolizing enzyme activities can be enhanced by arginine and methionine, suggesting that arginine and methionine have potent ethanol-metabolizing activities.

Effect of Silkworm (Bombyx mori) Excrement Powder on the Alcoholic Hepatotoxicity in Rats

The purpose of present study was to investigate the protective effect of silkworm excrement powder (SEP) on alcohol-induced hepatotoxicity in rats. Semisynthetic diet supplemented with SEP (3%, w/w) given to alcohol-feeding rats for 30 days, then blood and tissues were collected, processed and used for alcohol concentration mensuration, various biochemical estimations and histopathological examination. Chronic alcohol administration resulted in significantly increase in the activities of the clinically important liver marker enzymes, alanine aminotransferase (ALT), aspartate aminotransferase (AST), γ-glutamyl transpeptidase (γ-GTP) and lactate dehydrogenase (LDH). Also, a highly significant increase in the blood alcohol level by alcohol treatment was observed. But alcohol-induced elevation of ALT and LDH levels markedly prevented and the level of blood alcohol decreased in SEP treated rats as compared to alcohol-administered control rats. SEP supplementation showed highly decreased the concentrations of total lipid, triglyceride and cholesterol in serum, as compared with alcohol treated control rats. Alcohol treatment induced the marked accumulation of large lipid droplets, hepatocytes necrosis and inflammation in the liver, but SEP administration attenuated to alcohol-induced accumulation of lipid droplets and hepatocyte necrosis. The results indicated that SEP may exert a protective effect against alcoholic hepatotoxicity through decreasing the activity of hepatic marker enzymes.

RETRACTED: Hepatoprotective effects on alcoholic liver disease of fermented silkworms with Bacillus subtilis and Aspergillus kawachii

RETRACTED