• Nutrition Research and Practice
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• v.15 no.5
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• pp.568-578
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• 2021

BACKGROUND/OBJECTIVES: Psidium guajava L. (guava) leaves have been shown to exhibit hypoglycemic and antidiabetic effects in rodents. This study investigated the effects of guava leaf extract on adipogenesis, glucose uptake, and lipolysis of adipocytes to examine whether the antidiabetic properties are mediated through direct effects on adipocytes. MATERIALS/METHODS: 3T3-L1 cells were treated with 25, 50, 100 ㎍/mL of methanol extract from guava leaf extract (GLE) or 0.1% dimethyl sulfoxide as a control. Lipid accumulation was evaluated with Oil Red O Staining and AdipoRed assay. Immunoblotting was performed to measure the expression of adipogenic transcription factors, fatty acid synthase (FAS), and AMP-activated protein kinase (AMPK). Glucose uptake under basal or insulin-stimulated condition was measured using a glucose analog 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino]-2-deoxy-D-glucose. Lipolysis from fully differentiated adipocytes was measured by free fatty acids release into the culture medium in the presence or absence of epinephrine. RESULTS: Oil Red O staining and AdipoRed assay have shown that GLE treatment reduced lipid accumulation during adipocyte differentiation. Mitotic clonal expansion, an early essential event for adipocyte differentiation, was inhibited by GLE treatment. GLE inhibited the expression of transcription factors involved in adipocyte differentiation, such as peroxisome proliferator-activated receptor 𝛄 (PPAR𝛄), CCAAT/enhancer-binding protein α (C/EBPα), and sterol regulatory element-binding protein-1c (SREBP-1c). FAS expression was also decreased while the phosphorylation of AMPK was increased by GLE treatment. In addition, GLE increased insulin-induced glucose uptake into adipocytes. In lipid-filled mature adipocytes, GLE enhanced epinephrine-induced lipolysis but reduced basal lipolysis dose-dependently. CONCLUSIONS: The results show that GLE inhibits adipogenesis and improves adipocyte function by reducing basal lipolysis and increasing insulin-stimulated glucose uptake in adipocytes, which can be partly associated with antidiabetic effects of guava leaves.

• Journal of Nutrition and Health
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• v.40 no.3
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• pp.221-228
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• 2007

We determined the effects of dietary manipulations on messenger RNA of peroxisome proliferators activated receptor isoforms (i.e., PPAR ${\alpha},\;{\beta}/{\delta},\;{\gamma}$) in red vastus lateralis muscle of rats. Total 16 male Sprague-Dawley rats were used, and animals were divided into one of two dietary conditions: either chow diet group (CHOW; n=8) in which animals were 134 with standard rodent chow (61.8% carbohydrate, 15.7% fat, 22.5% protein) or high fat diet group (FAT n=8) in which animals were fed 24.3% carbohydrate, 52.8% fat, 22.9% protein. At the end of the 8 weeks of experimental period, red vastus lateralis muscle was dissected out from all animals, and PPAR ${\alpha},\;{\beta}/{\delta},\;{\gamma}$ mRNA expression was determined. There was no significant difference in body mass (BM) between CHOW and FAT. As expected, blood glucose and free fatty acid (FFA) concentration was higher in FAT than CHOW (p<0.05), and lactate concentration was significantly lower in FAT compared to CHOW (p<0.05). Insulin concentration tended to higher in FAT than CHOW ($67.2{\pm}21.9\;vs.\;27.0{\pm}5.2$ pmol/L), but it did not reach to the statistical significance. Gene expression of PPAR ${\alpha}$ was not significantly different between CHOW and FAT. It was not also significantly different in PPAR ${\beta}/{\delta}$. Interestingly, expression of mRNA in PPAR ${\gamma}$ however, was markedly depressed in FAT compared to CHOW (approximately 3 fold higher in CHOW; p<0.05). Results obtained from present study implies that PPAR ${\gamma}$ (as compensatory function of PPAR ${\alpha}$ is expressed) possibly exerts another major tuning roles in fatty acid transport, utilization, as well as biosynthesis in skeletal muscle cells. The situations and conditions that can be postulated for this implication need to be further examined.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.9
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• pp.1137-1142
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• 2017

This study examined the effects of apios (Apios americana Medikus) supplementation on visceral obesity in high-fat diet-induced obese mice. C57BL/6N mice were fed a high-fat diet (40% calories from fat) with or without apios powder (10%, w/w) for 12 weeks. At the end of the experiment, apios supplementation reduced visceral fat mass significantly by 14.3% compared to the control group. Apios decreased significantly the atherogenic index, serum leptin level, hepatic lipid (free fatty acid and triglyceride) content, and lipid droplets, whereas it increased the serum high density lipoprotein-cholesterol/total cholesterol ratio. Hepatic lipogenic gene expression of peroxisome proliferator activated receptor gamma, fatty acid synthase, and diacylglycerol O-acyltransferase 2 was down-regulated by apios supplementation. These results suggest that apios is a healthy food for preventing high-fat diet-induced visceral obesity and fatty liver.

• Journal of Korean Medicine for Obesity Research
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• v.24 no.1
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• pp.1-12
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• 2024

Objectives: Ephedrae herba (EH) and Coicis semen (CS) has been frequently prescribed for the treatment of obesity. However, effects of combinational extracts of these two herbs on non-alcoholic fatty liver disease are unknown. The aim of the present study was to investigate the effects of EH and CS on lipid accumulation and glucose absorption in free fatty acids (FFAs) or palmitic acid (PA)-treated HepG2 cells. Methods: Five samples of EH and CS were extracted by combination ratios (S1=0:100, S2=25:75, S3=50:50, S4=75:25, S5=100:0). Oil Red O staining was used to measure lipid accumulation in FFAs-induced steatosis cells. Intracellular triglycerides and total cholesterol levels were measured in FFAs-induced steatotic HepG2 cells. In PA-treated cells, intracellular 2-NBDG was detected using a fluorescence microplate reader and flow cytometry. Phosphorylation of key metabolism-related factors of AMP-activated protein kinase and acetyl-CoA carboxylase, expression of key lipid synthesis-related factors carnitine palmitoyltransferase 1 alpha (CPT1α), sterol regulatory element-binding protein 1 (SREBP1), peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT enhancer binding protein alpha (C/EBPα) were confirmed by western blot. Results: Treatment of EH-CS combination in the FFAs-induced steatotic HepG2 cells significantly reduced lipid accumulation. As the relative ratio of Ephedrae herba increased, the lipid-lowering effects of the combination were increased. However, S1 and S5 of Ephedrae herba and Coicis semen did not significantly reduce triglycerides and total cholesterol induced by FFAs. However, the combination of Ephedrae herba and Coicis semen restored glucose absorption in PA-induced HepG2 cells. Major makers of SREBP1, PPARγ, C/EBPα, and CPT1α expression tended to decrease with EH ratio. Conclusions: The EH-CS combination has advantages over sole EH and CS extracts in improving lipid and glucose metabolism in liver steatosis models.

• Biomolecules & Therapeutics
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• v.12 no.4
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• pp.215-220
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• 2004

In an attempt to develop new anti-diabetic agents, a series of aryloxypropanolamine derivatives was synthesized to serve as ${\beta}_3$ adrenoceptor agonists. Among these derivatives, 1-{1-methyl-3-[4-(2-methyl-2H-1,2,3,4-tetrazol-5-yl)phenyl]propylamino}-3-phenoxy-2-propanol (KR60886) possessed a high affinity for the ${\beta}_3$ adrenoceptor (Ki = 28 nM) and moderate affinities for ${\beta}_1$ and ${\beta}_2$ adrenoceptors (Ki = 95 nM and 100 nM, respectively). In addition, KR60886 stimulated cAMP production with an EC$_{50}$ of 0.4 ${\mu}M$, confirming its agonistic activity for the ${\beta}_3$ adrenoceptor. In vivo activities of KR60886 were examined by using a fat-fed/streptozotocin (STZ)-treated rat model and the ob/ob mouse model. Oral administration of KR60886 (10 mg/kg) for 3 days (b.i.d.) to fat-fed/STZ-treated rats significantly lowered plasma glucose levels and reduced plasma free fatty acid concentrations. Similarly, KR60886 treatment (10 mg/kg/day for 7 d) resulted in a reduction of plasma glucose concentrations in ob/ob mice. The present study suggests that KR60886 is a potent ${\beta}_3$ receptor agonist with in vivo anti-diabetic properties.

• Korean Journal of Food Science and Technology
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• v.48 no.4
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• pp.384-391
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• 2016

In previous studies, we confirmed that the ethanol extract of Polygonatum sibiricum (ID1216) has anti-obesity effects on high-fat diet-fed mice. To identify the obesity-related genes affected by ID1216, we studied its effects both in vivo and in vitro. In mice, single administration of ID1216 increased the expression of obesity-related genes including sirtuin1 (SIRT1), peroxisome proliferator-activated receptor ${\gamma}$ coactivator $1{\alpha}$ ($PGC1{\alpha}$) and peroxisome proliferator-activated receptor ${\alpha}$ ($PPAR{\alpha}$) compared to that in mice administered the vehicle; their downstream genes (uncoupling proteins, acyl-CoA oxidase, adipocyte protein 2, and hormone-sensitive lipase) were also increased by ID1216. In fully differentiated 3T3-L1 adipocytes, ID1216 showed the same effects on anti-obesity genes as those in the animal model. Based on these results, we propose that ID1216 has anti-obesity effects by regulating the $SIRT1-PGC1{\alpha}-PPAR{\alpha}$ pathway and their downstream genes, thereby controlling energy and lipid metabolisms.

• The Korean Journal of Physiology and Pharmacology
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• v.14 no.2
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• pp.77-81
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• 2010

Plasma cholesterol is increased in normal aging in both rodents and humans. This is associated with reduced elimination of cholesterol and decreased receptor-mediated clearance of plasma low-density lipoprotein (LDL) cholesterol. The aims of this study were: (1) to determine age-related changes in plasma lipid profiles, and (2) to determine the effect of fenofibrate, an activator of peroxisome proliferator activated receptor alpha (PPAR $\alpha$), on plasma lipid profiles in normal rats on a standard diet. Male Sprague-Dawley (SD) rats (n=15) were fed standard chow and water from 10 to 25 weeks of age. During that period, we measured daily food intake, body weight, fasting and random blood glucose levels, plasma total cholesterol (TC), triglycerides (TG), and free fatty acid (FFA) levels. At 20 weeks of age, all rats were randomly divided into two groups: a fenofibrate group (in which rats were gavaged with 300 mg/kg/day of fenofibrate) and a control group (gavaged with water). Fenofibrate treatment lasted 5 weeks. There were no significant changes in daily food intake, blood glucose, and plasma TG level with age. Body weight, plasma TC, and FFA levels were significantly increased with age. Fenofibrate significantly decreased plasma concentrations of TC and FFA, which had been increased with age. However, fenofibrate did not influence the plasma concentration of TG, which had not increased with age. These results suggest that fenofibrate might have a novel role in preventing age-related hypercholesterolemia in SD rats on a normal diet.