• Preventive Nutrition and Food Science
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• v.6 no.2
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• pp.122-125
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• 2001

A potential mechanism through which the jujube extract might produce a cholesterol-lowering effect was compared with that of tangerine peel extract in vivo. Two extracts were prepared using ethanol. Male rats were fed a high cholesterol (1%, w/w) lab chow with jujube extract (1.2%) or tangerine peel extract (6.3%, w/w) for 3 weeks. Activities of hepatic HMG-CoA reductase (289.6$\pm$12.9 and 296.7$\pm$11.6 nmole/min/mg vs. 347.9$\pm$17.5 nmole/min/mg) and ACAT (554.8$\pm$18.2 and 451.7$\pm$19.4 nmole/min/mg vs. 602.6$\pm$21.4 nmole/min/mg) were significantly lowered by both supplements compared to the control group. These two supplements also substantially reduced the concentrations of plasma cholesterol (103.3$\pm$15.9 and 101.6$\pm$19.4 mg/dL vs. 141.6$\pm$18.1 mg/dL) and triglyceride (61.3$\pm$5.5 and 55.5$\pm$3.9 mg/dL vs. 96.0$\pm$4.2 mg/dL). The inhibition of HMG-CoA reductase resulting from the supplementation of jujube or tangerine extracts could count for the reduction in plasma cholesterol. Accordingly, lipid-lowering action of both supplements appears to be similar in high-cholesterol fed rats.

• Nutritional Sciences
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• v.9 no.4
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• pp.259-266
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• 2006

The current study examined the effect of quercetin supplements on the lipid-lowering and antioxidant metabolism in ethanol-fed rats. The control $group(E_8)$ received ethanol only diet for 8 wks, whereas the other group$(E_8Q_4)$ received a diet including quercetin supplementation(0.05% wt/wt) for 4 wks while on the ethanol diet for 8wks. The hepatic alcohol dehydrogenase activity was significantly higher in the $E_8Q_4$ group than in the $E_8$ group. Supplementation with quercetin significantly elevated the HDL- cholesterol concentration, the HDL-C/total-C ratio, and lowered the atherogenic index(AI) compared to the $E_8$ group. The hepatic triglyceride and cholesterol contents were significantly lowered by the quercetin supplement compared to those of the control group. The hepatic HMG-CoA reductase and ACAT activities of the $E_8Q_4$ group were significantly lower than those of the $E_8$ group. The overall potential for antioxidant defense was significantly enhanced by the quercetin supplement, as indicated by a decrease in plasma and hepatic TBARS levels. The hepatic GSH-Px and G6PD activities were significantly higher in the $E_8Q_4$ group compared to the $E_8$ group. The current results suggest that dietary quercetin leads to the inhibition of HMG-CoA reductase and ACAT, which in turn lowers cholesterol levels and normalizes antioxidant enzyme activities.

• Journal of Physiology & Pathology in Korean Medicine
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• v.38 no.1
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• pp.27-31
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• 2024

Dried fruits of Amomum villosum Lour. have been used an korean medicine to treat digestive diseases for a long time. It has been reported that Amomum villosum extracts(AVE) have effects for diabetes and steatosis in experimental models. But we did not find the report about the cholesterol synthesis inhibition effects of AVE. The objective of this study is to clarify the inhibitory effect of AVE against oleic acid and glucose-induced hypercholesterolemia in HepG2 cells. The results show that AVE had a significant inhibitory effect against oleic acid and glucose-induced cholesterol accumulation. Those effects seem to be caused by inhibition of AVE on oleic acid and glucose-induced decrease of HMG CoA reductase, which is the rate-limiting enzyme for cholesterol biosynthesis in liver. It is believed that the results of this study can provide basic data for the drug and functional food development of hypercholesterolemia treatments.

• Food Science and Biotechnology
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• v.14 no.6
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• pp.727-731
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• 2005

Synthesized Ile-Ala-Val-Pro (IAVP) peptide, which has the highest hypocholesterolemic effect among a number of synthesized derivatives of Ile-Ala-Val-Pro-Gly-Glu-Val-Ala (IAVPGEVA) isolated from 11S globulin of soy protein by pepsin digestion, was selected for investigation in the present study. Using a recombinant Syrian hamster 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR), we studied in detail the inhibition of this enzyme by IAVP and compared the action of this peptide to that of lovastatin, a known competitive inhibitor of this enzyme. The concentration of IAVP required for 50% inhibition ($IC_{50}$) of HMGR activity in given experimental conditions was $340\;{\mu}M$. Kinetic analysis revealed that the studied peptide is a competitive inhibitor of HMGR with respect to both 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) and nicotinamide adenine dinucleotide phosphate (NADPH), with an equilibrium constant of inhibitor binding ($K_i\;=\;[E][I]/[EI]$) of $61{\pm}1.2\;{\mu}M$ and $157{\pm}4.4\;{\mu}M$, respectively. At the same conditions, $K_i$ and $IC_{50}$ for lovastatin were $2.2{\pm}0.1\;nM$ and 12.5 nM, respectively. Thus, the given peptide interacts with HMGR as a bisubstrate, consequently blocking access of both substrates to the active sites. The achieved results suggest the design of new peptide sequences having a higher relative affinity to binding sites of this enzyme and an enhancement of their hypocholesterolemic properties.

• KSBB Journal
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• v.24 no.2
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• pp.163-169
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• 2009

Lovastatin (also known as Mevinolin, Mevacor, and Monacolin K), an inhibitor of the HMG-CoA reductase produced by Aspergillus terreus and other fungi, is used to reduce serum cholesterol levels in human beings. It is derived biosynthetically from two polyketides. One of these is a nonaketide that undergoes cyclization at a hexahydronaphthalene ring system, and the other is a simple diketide, 2-methylbutyrate. Two primer pairs were designed based on the amino acid sequences of lovastatin polyketide synthase and lovastatin diketide synthase for the PCR screening of lovastatin-producing strains. Among the seven selected strains, SJ-2 evidenced the highest level of lovastatin production in both liquid and solid cultures. Soybeans with SJ-2 were treated via 1 hour of heat shock at $30^{\circ}C$ for the mass production of lovastatin. The heat-treated soybeans were inoculated on rice bran and the koji extract was obtained after 15 days of incubation. It yielded the highest level of lovastatin production among the strains, and also evidenced 75% inhibition activity against HMG-CoA reductase. We developed an efficient PCR screening method for lovastatin-producing strains, using lovastatin biosynthesis genes.

• Korean Journal of Acupuncture
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• v.27 no.3
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• pp.25-46
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• 2010

Objective & Methods : The purpose of this study is to observe the effects of herbal- acupuncture with Achyranthis Radix(AR-HA) at GB34(Yangleungchean) on hyperlipidemia in rats. The author performed several experimental items to analyze the levels of various components and enzymes in serum and liver, as well as the histological changes of liver and aorta. Results : 1. Achyranthis Radix herbal acupuncture solution increased DPPH radical scavenging activity and HMG-CoA reductase inhibition rate in rat liver cells. 2. AR-HA at GB34 decreased the level of serum total cholesterol, and increased the ratios of HDL-cholesterol to total cholesterol, phospholipid to total cholesterol in hyperlipidemic rat. 3. AR-HA at GB34 decreased the hepatic HMG-CoA reductase activity in hyperlipidemic rat. 4. AR-HA at GB34 increased the hepatic GSH level in hyperlipidemic rat. Conclusion : From the above results, it is suggested that AR-HA at GB34 has a therapeutic effect on hyperlipidemia.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.12
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• pp.1899-1907
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• 2013

We investigated the effects of unripe black raspberry water extract (UBR-W) and oxidation-LDL treatment on cholesterol levels. Experiments using an established human hepatocellular carcinoma cell line (HepG2) showed a time-dependent increase in expression of LDL receptor after UBR-W treatment. Expression of LDL receptor-related genes, such as SREBP1 and 2, increased upon UBR-W treatment. However, expression of HDL-related genes was unaffected by UBR-W. HMG-CoA reductase activity was reduced by UBR-W treatment, whereas HMG-CoA mRNA expression significantly increased. In addition, the ApoB/ApoA1 mRNA level, which is a predictor of cardiovascular risk, was reduced in a time-dependent manner by UBR-W treatment. Macrophage-like cells (RAW 264.7) showed increased expression of ox-LDL-related genes, such as CD36, scavenger receptor-A, adipophilin, and PPAR-gamma, upon ox-LDL treatment compared to untreated control cells, and quantitative lipid analysis indicated a dramatic increase in lipid accumulation. However, UBR-W treatment significantly reduced expression of ox-LDL-related genes and largely prevented lipid accumulation. The results indicate that UBR-W mediates a cholesterol-lowering effect via inhibition of cholesterol synthesis and induction of LDL uptake through SREBP.

• Korean Journal of Food Science and Technology
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• v.52 no.5
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• pp.427-434
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• 2020

This study was performed to compare nutritional compounds and physiological functions of five domestic and imported green tea cultivars at three time points. The five cultivars were compared for theanine, γ-aminobutyric acid, and catechin content by LC-MS/MS and HPLC. Furthermore, the five tea cultivars were functionally characterized with respect to antioxidant activity, brain cell protective effect, and inhibitions of α-glucosidase and HMG-CoA reductase activities. Among green tea cultivars, Chamnok had the highest content of catechins (198 mg/g DW), theanine (11.89 mg/g DW), and tannin (23.6 mg/g DW). Considering functional properties, Chamnok treatment resulted in the maximum viability of brain cells and reduced the cortisol content of SH-SY5Y cells. The inhibition of α-glucosidase and HMG-CoA reductase was the strongest following Chamnok treatment (72.9% and 69.8%, respectively). These results indicate that Chamnok could be optimal for consumption or favorable processing owing to its high nutritional compounds, such as theanine and catechin, and remarkable brain cell protective effects.

• The Journal of Korean Medicine
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• v.38 no.3
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• pp.43-58
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• 2017

Objectives: We performed this study to evaluate the antioxidative and hypolipidemic effect of Artemisia iwayomogi (韓茵蔯), Curcuma longa L. (鬱金) and Raphanus sativus L. (蘿?子) (ACR). Method: We enriched Artemisiae Capillaris, Curcumae Longae and Raphani Semen compound with alcohol. ACR extract is treated to HepG2 cell. Cell groups are devided into 3 groups: normal, control and ACR treated group. We measured polyphenol, flavonoids, DPPH and ABTS radical scavenging activity, ROS, glutathione, GSH peroxidase, GSH reductase, SOD, catalase, free fatty acid, lipid peroxidation and suppression of ACAT1 and HMG-CoA reductase expression on mRNA level. Results: 1. ACR contained polyphenol and flavonoids and increased GSH significantly in HepG2 cell. 2. ACR increased GPx, GR, and catalase activity significantly in HepG2 cell. 3. ACR increased DPPH and ABTS radical scavenging activity significantly in HepG2 cell and decreased ROS. 4. ACR decreased free fatty acid and MDA significantly in HepG2 cell. 5. ACR suppressed ACAT1 and HMG-CoA reductase expression on mRNA level in HepG2 cell. Conclusion: This study suggests that ACR has antioxidative and hypolipidemic effect and might be effective in prevention and treatment of dyslipidemia.

• Nutrition Research and Practice
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• v.5 no.5
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• pp.412-420
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• 2011

The aim of the present study was to investigate the hypocholesterolemic effect and potential of tyramine derivatives from Lycii Cortex Radicis (LCR), the root bark of lycium (Lycium chenese Miller) in reducing lipid peroxidation. The activities of enzymes, hepatic 3-hydroxy 3-methylglutaryl (HMG) CoA reductase and acyl-CoA:cholesterol acyltransferase (ACAT) and LDL oxidation were measured in vitro and animal experiments were also performed by feeding LCR extracts to rats. The test compounds employed for in vitro study were trans-N-p-coumaroyltyramine (CT) and trans-N-feruloyltyramine (FT), LCR components, N-(p-coumaroyl)serotonin (CS) and N-feruloylserotonin (FS) from safflower seeds, ferulic acid (FA) and 10-gingerol. It was observed that FT and FS at the concentration of 1.2 mg/mL inhibited liver microsomal HMG CoA reductase activity by ~40%, but no inhibition of activity was seen in the cases of CT, CS, FA and 10-gingerol. Whereas, ACAT activity was inhibited ~50% by FT and CT, 34-43% by FS and CS and ~80% by 10-gingerol at the concentration of 1 mg/mL. A significant delay in LDL oxidation was induced by CT, FT, and 10-gingerol. For the animal experiment, five groups of Sprague-Dawley male rats were fed high fat diets containing no test material (HF-control), 1 and 2% of LCR ethanol extract (LCR1 and LCR2), and 1% of extracts from safflower seed (Sat) and ginger (Gin). The results indicated that total cholesterol level was significantly lower in Saf, LCR2 and Gin groups, and HDL cholesterol level was lower only in Gin group when compared with HF-control group; while there was no difference in the serum triglyceride levels among the five experimental groups. The level of liver cholesterol was significantly lower in LCR1 and LCR2 groups than HF-control Serum levels of TBARS were significantly lower only in LCR2 group when compared with HF-control group. From the observed results, we concluded that LCR can be utilized as a hypocholesterolemic ingredient in combination with ginger, especially for functional foods.