• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.6
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• pp.1187-1193
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• 1997

The purpose of this study was to investigate the effects of green tea catechin on lipid metabolism in streptozotocin(STZ)-induced diabetic rats. Male Sprague-Dawley rats weighing 150$\pm$10gm were randomly assigned to one normal and three STZ-induced diabetic groups. Diabetic animals were fed catechin free diet(DM-0C group), 0.5% catechin diet(DM-0.5C group) and 1% catechin diet(DM-1C group). Diabetes was experimentally induced by intravenous injection of 55mg/kg body wt of STZ in citrate buffer(pH 4.3) after feeding of three experimental diets for 4 weeks. Animals were sacrificed at the 6th day of diabetic states. Levels of blood glucose were three fold higher in all three STZ-induced diabetic groups than that of the normal group. The levels of plasma insulin were markedly lower in three STZ-induced diabetic groups than that of the normal group. The levels of plasma cortisol were increased in DM-0C group compared with that of the normal group. Triglyceride, total-cholesterol and LDL-cholesterol levels in serum were increased in DM-0C groups compared with the normal group but were not significantly different between catechin diet groups and normal group. Serum HDL-cholesterol levels were reduced in DM-0C and DM-0.5C groups by 38% and 25%, respectively and had similar tendency in the DM-1C group compared with that of control group. Atherogenic index have shown same pattern as the result of total cholesterol. Activities of 3-hydroxy-3-methylglutaryl Co enzyme A(HMG-CoA) reductase were higher in DM-0C groups than those of the normal group but were not significantly different between catechin diet groups and the normal group. It is concluded that dietary catechins can modulate lipid levels of serum and liver HMG-CoA reductase activity in diabetic rats.

• KSBB Journal
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• v.6 no.1
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• pp.55-61
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• 1991

The objective of this in vitro study is to screen a possible inhibitor, originated from some chinese herb medicines, of 3-hydroxy-3-methylglutaryl Coenzyme A (HMG-CoA) reductase that is the major regulatory enzyme of hepatic cholesterol biosynthesis. Fourteen kinds of herbal plant were extracted with water and evaporated for prescreening. The methanol extracts of the effective 3 kinds (9 species) were fractionated with chloroform, ethylacetate, butanol and water, and vacuum evaporated. The degree of inhibition of the extracts to HMG-CoA reductase activity was calculated by the spectrophotometric method using microsomal protein of Saccharomyces cerevisiae ATCC 42949 as an enzyme source. Among these samples, marked inhibitory effects were observed in the extracts of ethylacetate and chloroform fractions of the Rosa rugosa roots, and those of butanol, ehtylacetate and water fractions of pine leaves. Also, the inhibitory effects of the extracts obtained from buckwheat shell and the roots of Rosaceae were found.

• Journal of Nutrition and Health
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• v.31 no.9
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• pp.1394-1403
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• 1998

The study was designed to observe the effect of dietary calcium and fats on plasma cholesterol level, hepatic microsomal fluidity and HMG-CoA reductase activity as well as the excretion of fecal bile acids and neutral sterols in 1, 2-dimethylhydrazine(DMH)-treated rats. Male Sprague Dawley rats, at 7 weeks of age, were divided into 2 groups, 0.3% and 1.0% Ca levels and each group again subdivided into 2 groups of corn oil and perilla oil. Each rat was intramuscularly infused with DMH for 6 weeks to give total dose of 180mg/kg body weight and also fed experimental diet containing 15%(w/w) different fit and Ca(0.3% or 1.0%) for 20 weeks. High dietary calcium(1.0%) did not significantly influence on plasma cholesterol as well as hepatic microsomal fluidity and HMG CoA reductase activity, but significantly reduced the excretion of total bile acid per gram of faces and increased the excretion of total neutral sterol. However, high dietary Ca reduced the excretion of secondary bile acid(deoxycholic and lithocholic acids) which was known as promoter for colon cancer. Perilla oil rich in n-3 ${\alpha}$-linolenic acid significantly decreased plasma cholesterol by increasing hepatic microsomal fluidity compared with corn oil, but did not influence on HMG CoA reductase activity. Perilla oil did not influence on fecal excretion of total and primary bile acids, but reduced the excretion of secondary bile acids. Therefore, it could be recommended to consume more fish product and food rich in calcium and use more perilla oil in meal preparation to prevent from coronary hear disease and colon cancer especially when high fit diet has been practiced. (Korean Nutrition 31(9) : 1394-1403, 1998)

• Journal of Applied Biological Chemistry
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• v.61 no.1
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• pp.1-8
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• 2018

The objective of this study was to compare the antihyperlipidemic effects of different Dendropanax morbifera leaf extracts in vitro. The extracts differed in terms of specimen age, harvesting season, and extraction method. RAW 264.7 cells were pretreated with these extracts and stimulated by oxidized low-density lipoprotein. Ethanol was used to induce toxicity in HepG2 cells. Cellular lipid accumulation was quantified using oil red O staining in both these cells. The extracts were evaluated for their inhibitory effects on 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase. RAW 264.7 cells treated with the 60% ethanol extract of an 8-year-old specimen harvested in November exhibited the lowest lipid accumulation. The 30% ethanol extract of a 5-year-old specimen harvested in May exhibited the greatest protection from ethanol-induced cytotoxicity in HepG2 cells. The hot water extract of an 8-year-old specimen harvested in May showed the greatest inhibition of HMG-CoA reductase. These results showed that D. morbifera extracts prepared from leaves that are harvested in May possess the highest antihyperlipidemic effects.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.12
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• pp.1779-1784
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• 2015

This study was performed to investigate the effects of various garlic extracts on cholesterol synthesis in HepG2 cells. Raw garlic, grilled garlic, and freeze dried garlic were subjected to cold water extraction, and extracts were incubated at room temperature for 1 min or 60 min. The extracts were treated to HepG2 cells for 4 h, and cholesterol synthesis and mRNA expression level of HMG-CoA reductase were investigated. The alliin contents were reduced when garlic was incubated at room temperature for 60 min. Raw garlic extracts showed lower intracellular cholesterol contents compared to that of the control group. However, raw garlic extracts incubated for 60 min showed no differences compared to the control group. Freeze-dried garlic extract showed minimum intracellular triglyceride and cholesterol contents. Relative mRNA expression level of HMG-CoA reductase, a rate-limiting enzyme of cholesterol synthesis, decreased in the garlic extracts. Compared with 60 min, garlic extracts incubated for 1 min showed a reduced level of HMG-CoA reductase mRNA expression. The freeze-dried garlic extract reduced mRNA expression level of HMG-CoA reductase in a dose-dependent manner in cells treated with 5% of 0.2, 0.5, 0.8, 1.0, and 1.5 mg/mL in medium, and the effect was maxed out at dose of 5% garlic extract at 1.0 mg/mL in medium.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.5
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• pp.666-670
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• 2008

Lovastatin (Mevinolin, Monacolin K) is a well-known drug for the therapy of hypercholesterolemia. It is an important fungal secondary metabolite as it inhibits 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG-CoA reductase, EC 1.1.1.34) which catalyzes a major rate-limiting step in the biosynthesis of cholesterol. Both soybeans and black soybeans with Aspergillus terreus ATCC 20542 mutant were used as the seed culture for the mass production of lovastatin. The production of lovastatin in soybean seed culture of Asp. terreus was twofold compared to that of black soybean seed culture. The effect of two different vessels (petri dish and Erlenmeyer flask) on lovastatin production was also studied. The production of lovastatin on petri dish was tenfold to that of Erlenmeyer flask. Furthermore, the most lovastatin production on rice bran was achieved when the soybean seed culture was treated by heat shock at $30^{\circ}C$ for 1 hour, representing 82% of HMG-CoA reductase inhibition in the koji extract. We estimated that the heat treated soybean seed culture could be a new method for the mass production of lovastatin.

• Journal of Food Hygiene and Safety
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• v.36 no.4
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• pp.353-362
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• 2021

Ecklonia stolonifera, which belongs to the family Laminariaceae, is an edible perennial brown marine alga that is widely distributed, and is rich in polyphenols, including dieckol. Here, we investigated the radical scavenging activities of E. stolonifera extract (ESE) using various in vitro models. We further evaluated the effect of ESE on the cholesterol secretion inhibition activity in HepG2 cells, as well as the hydroxymethylglutaryl-coenzyme A (HMG-CoA) reductase activity. Our results showed that the total phenol, total flavonoid, and dieckol contents of ESE were 9.64±0.04 mg GAE/g, 2.72±0.08 mg RE/g and 27.42±0.66 mg/g, respectively. The antioxidant activity of ESE increased in a dose-dependent manner. In addition, the ESE inhibited cholesterol secretion from HepG2 cells with anti-HMG-CoA reductase activity. These results suggested that ESE possesses antioxidant and anti-cholesterol activities, and can therefore be used as a preclinical bioresource for development of health functional foods.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.3
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• pp.392-398
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• 1996

This study was carried out to determine the effects of sodium alginate and cellulose on the cholesterol metabolism in cholesterol-fed rats. Thirty male Sprague-Dawley rats were randomly assigned to three dietary treatments. Rats were fed, ad libitum, diets containing 10% dietary fibers as sodium alginate, cellulose or fiber-free with 1% cholesterol for 4 weeks. The results obtained were as follows: the feeding of sodium alginate with 1% cholesterol induced a significant decrease in plasma cholesterol and TG. The feeding of sodium alginate significantly decreased hepatic total lipids and TG levels, whereas the feeding of sodium alginate significantly increased hepatic HMG-CoA reductase activity. The feeding of sodium alginate and cellulose significantly increased fecal cholesterol and bile acid excretion. The excretion of TG in sodium alginate group, however, was two-fold and four-fold increased compared to cellulose and fiber-free group, respectively. As a result of this study, the ingestion of sodium alginate decreased plasma cholesterol and TG concentrations and liver TG concentration. This may be explained by the facts that fecal cholesterol, bile acid and TG level were increased significantly in sodium alginate group. The increased hepatic HMG-CoA reductase activity by sodium alginate feeding appears to be corresponded to whole-body cholesterol homeostasis.

• Journal of Nutrition and Health
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• v.32 no.6
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• pp.637-643
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• 1999

The effects of yam(Dioscorea) on lowering cholesterol level and its mechanism were investigated. The concentrations of plasma and liver lipids, and the excretions of fecal neutral sterol and bile acid were measured in male Sprague-Dawley rats. Five Groups of 8 rats were fed hypercholesterolemic diet(1% cholesterol, 10% lard ; control), hypercholesterolemic diet plus 15% or 30% dried yam powder prepared by either hot-air(15HY, 30HY) or freeze dry(15FY, 30FY) for 4wk. Plasma total lipid, total cholesterol and cholesterol level was also significantly lower(28%, p<0.05), buy HMG-CoA reductase activity was higher in 30FY(230%, p<0.05) than in control. Although no significant differences in fecal neutral sterols were observed among groups, the yam-fed rats apparently had less bacterial degradation of cholesterol as indicated by a significantly greater of fecal cholesterol to coprostanol than in controls. Total fecal bile acids were significantly greater in rats fed yam(15HY : 5 folds, 15FY ; 12,30HY ; 12, 20FY ; 22) than in controls. The ratio of secondary to primary bile acids was almost 8 times lower in 30FY than in control. These data indicate that yam lowers cholesterol both in plasma and in liver through increasing fecal bile acid excretion as well as HMG-CoA reductase activity. Freeze-dried yam, which possesses viscosity, was more effective in cholesterol-lowering action than hot-air dried one.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.5
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• pp.826-833
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• 2002

This study was conducted to investigate the effects of YK-209 mulberry leaves on HMG-CoA reductase activity and lipid composition of liver in streptozotocin-induced diabetic rats. Sprague-Dawley male rats weighing 100 $\pm$ 10 B were randomly assigned as a normal group and four STZ-induced diabetic groups according to the level of dietary mulberry leaves supplement. The experimental diets were fed ad libidum, so that diabetes was experimentally induced by intravenous injection of STZ 55 mg/kg of body weight after feeding for 3 weeks. Animals were sacrificed on the 9th day of diabetic states. The levels of serum triglyceride, total-cholesterol and LDL-cholesterol in DM group were higher than mulberry leaves supplemented groups and normal group, but those of the mulberry leaves supplemented groups were significantly decreased to normal level. In contrast, the leavels of serum HDL-cholesterol in DM group was significantly reduced than that of normal group, but mulberry leaves supplemented groups were increased to normal level. Atherogenic index in DM group was higher about 3 fold than the normal group but the DM-0.1Y and DM-0.2Y groups were maintained the normal level. Contents of total lipid and triglyceride of liver in DM group were significantly lower than that of normal group, but the mulberry Leaves supplemented groups increased than that of DM group. The contents of hepatic cholesterol in DM group was 160% higher than that of normal group, but the mulberry leaves supplementation groups maintained the normal level. The activity of hepatic 3-hydroxy -3-methylglutaryl Coenzyme A (HMG-CoA) reductase in DM group was 43% lower than that of normal group, but had no significant difference between DM-0.1Y, DM-0.2Y and normal groups. In conclusion, YK-209 mulberry loaves has improving effect of the lipid metabolism in STZ-induced diabetic rats through hepatic HMG-CoA reductase activity, and the change of lipids contents in serum and liver.