Hyeon-A Kim

Alterations in the blood glucose, serum lipids and renal oxidative stress in diabetic rats by supplementation of onion (Allium cepa. Linn)

This study examined the anti-diabetic effect of onion (Allium cepa. Linn) in the streptozotocin (STZ)-induced diabetic rats. Male Sprague-Dawley rats were divided into normal rats fed control diet or supplemented with onion powder (7% w/w) and diabetic rats fed control diet or supplemented with onion powder. Diabetes was induced by a single injection of STZ (60 mg/kg, ip) in citrate buffer. The animals were fed each of the experimental diet for 5 weeks. Blood glucose levels of rats supplemented with onion were lower than those of rats fed control diet in the diabetic rats. Onion also decreased the total serum lipid, triglyceride, and atherogenic index and increased HDL-cholesterol/total cholesterol ratio in the diabetic rats. Glutathione peroxidase, glutathione reductase and glutathione S-transferase activities were high in the diabetic rats compared to normal rats and reverted to near-control values by onion. These results indicate that onion decreased blood glucose, serum lipid levels and reduced renal oxidative stress in STZ-induced diabetic rats and this effect might exert the anti-diabetic effect of onion.

Anti-Obesity Effects of the Mixture of Eriobotrya japonica and Nelumbo nucifera in Adipocytes and High-Fat Diet-Induced Obese Mice.

The present study is to evaluate the anti-obesity effects of Eriobotrya japonica (EJ), Nelumbo nucifera (NN), and their mixture (MIX, 1:1 ratio) in 3T3-L1 adipocytes and high-fat diet-induced obese mice. The treatment of EJ, NN, and MIX in 3T3-L1 adipocytes effectively inhibited lipid accumulation, significantly decreased expression of peroxisome proliferator-activated receptor gamma (PPARγ), sterol regulatory element binding protein (SREBP1c), and adipocyte lipid-binding protein (aP2), and significantly increased phosphorylation of AMP-activated protein kinase (AMPK). Moreover, oral treatment of MIX showed stronger effects than individual treatment. C57BL/6J mice (6 week old) were divided into two groups; low fat diet (LFD) containing 10% calories from fat and high fat diet (HFD) containing 60% calories from fat. The HFD groups were further divided into five subgroups; treated with distilled water (HFD), treated with 400 mg/kg EJ (EJ400), treated with 400 mg/kg NN (NN400), treated with 200 mg/kg MIX (MIX200), and treated with 400 mg/kg MIX (MIX400) during 13 weeks. In our results, the administration of EJ, NN, and MIX significantly decreased body weight (BW), fat weight, liver weight, hepatic triglyceride (TG) and total cholesterol (TC), lipid droplets in the liver, food efficacy ratio, and the plasma TG, TC, glucose, insulin, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in a dose-dependent manner, and MIX treatment showed stronger effect than their individual treatments. Similarly, MIX treatment decreased the expression of PPARγ, SREBP-1c, FAS, and ACC more strongly in the adipose tissue than single treatments. In conclusion, the MIX of EJ and NN extract may strongly regulate BW gain than EJ or NN alone, and its anti-obesity effect is associated with the control of lipid metabolism, including adipogenesis and lipogenesis.

Loquat (Eriobotrya japonica) extracts suppress the adhesion, migration and invasion of human breast cancer cell line.

We examined the inhibitory effects of loquat methanol extract on the adhesion, migration, invasion and matrix metalloproteinase (MMP) activities of MDA-MB-231 human breast cancer cell line. Cells were cultured with DMSO or with 10, 25, or 50 µg/ml of loquat methanol extract. Both leaf and seed extracts significantly inhibited growth of MDA-MB-231 cells in a dose-dependent manner, although leaf extract was more effective. Adhesion and migration were significantly inhibited by loquat extracts in a dose-dependent manner. Loquat extract also inhibited the invasion of breast cancer cells in a dose-dependent manner and leaf extract was more effective than seed extract. MMP-2 and MMP-9 activities were also inhibited by loquat extract. Our results indicate that methanol extracts of loquat inhibit the adhesion, migration and invasion of human breast cancer cells partially through the inhibition of MMP activity and leaf extract has more anti-metastatic effects in cell based assay than seed extract. Clinical application of loquat extract as a potent chemopreventive agent may be helpful in limiting breast cancer invasion and metastasis.

Pear pomace water extract inhibits adipogenesis and induces apoptosis in 3T3-L1 adipocytes.

Obesity occurs when a persons calorie intake exceeds the amount of energy burns, which may lead to pathologic growth of adipocytes and the accumulation of fat in the tissues. In this study, the effect and mechanism of pear pomace extracts on 3T3-L1 adipocyte differentiation and apoptosis of mature adipocytes were investigated. The effects of pear pomace extract on cell viability and the anti-adipogenic and proapoptotic effects were investigated via MTT assay, Oil red O staining, western blot analysis and apoptosis assay. 3T3-L1 preadipocytes were stimulated with DMEM containing 10% FBS, 0.5 mM 3-isobutyl-1-methylxanthine (IBMX), 5 µg/ml insulin and 1 µM dexamethasone for differentiation to adipocytes. 3T3-L1 cells were cultured with PBS or water extract of pear pomace. Water extract of pear pomace effectively inhibited lipid accumulations and expressions of PPAR-γ and C/EBPα in 3T3-L1 cells. It also increased expression of p-AMPK and decreased the expression of SREBP-1c and FAS in 3T3-L1 cells. The induction of apoptosis was observed in 3T3-L1 cells treated with pear pomace. These results indicate that pear pomace water extract inhibits adipogenesis and induces apoptosis of adipocytes and thus can be used as a potential therapeutic substance as part of prevention or treatment strategy for obesity.

Changes in Salmon (Oncorhynchus keta) Flesh Quality Following Ultra-High Pressure Treatment and 30 d of Chilled Storage

The approximately 1.5 million tons of salmon traded in 31 countries in 2008 provides clear evidence that salmon is a popular food source throughout the world. There are many methods for the preservation of salmon flesh, such as vacuum-packaging, smoking, and freezing. Ultra-high pressure (UHP) does not require heat, preserves the quality of salmon flesh, and allows for an increase in the chilled storage period. In this study, the quality of salmon flesh was assessed after exposure to UHP (200, 400, or 600 MPa compared with no UHP) and 30 d of storage at 4 °C. Salmon flesh quality analyses included the degree of changes in the interspacing of muscle bundles, color, texture profiles (hardness, chewiness, cohesiveness, and elasticity), and microbial growth. The use of UHP (>400 MPa) improved the color, hardness, and chewiness of the flesh. Study results suggested that the application of UHP (≥400 MPa) may be useful in preserving salmon flesh, and could be used by the salmon aquaculture and distribution industries.

Effect of St. John's Wort (Hypericum perforatum) on obesity, lipid metabolism and uterine epithelial proliferation in ovariectomized rats

BACKGROUND/OBJECTIVES This study was conducted to assess the potential of St. Johns Wort (Hypericum perforatum) to prevent obesity and abnormalities in lipid metabolism induced by ovariectomy in a rat model without stimulatory activity on uterus. MATERIALS/METHODS Ovariectomized (OVX) rats were treated for 6 weeks with 70% ethanol extracts of Hypericum perforatum [HPEs: whole plant (WHPE) and flower and leaves (FLHPE)], β-estradiol-3-benzoate at a dose of 50 µg/kg/day (E2) or vehicle (distilled water). RESULTS As expected, OVX increased body weight gain and adiposity and showed higher food efficacy ratio. OVX also increased the serum cholesterol as well as insulin resistance, while reducing uterus weight and uterine epithelial proliferation rate. HPEs (WHPE and FLHPE) showed estrogen-like effect on body weight gain, adipose tissue weight and food efficacy ratio in OVX rats. HPEs prevented hypercholesterolemia induced by OVX more effectively than E2. E2 increased uterus weight and epithelial proliferation rate in OVX rats, while HPEs maintained them at the level of the sham-operated animals. CONCLUSIONS Our finding demonstrates that HPEs can be considered as an effective agent to prevent OVX-induced obesity without stimulatory activity on uterus.

Pear pomace ethanol extract improves insulin resistance through enhancement of insulin signaling pathway without lipid accumulation

BACKGROUND/OBJECTIVES The anti-diabetic activity of pear through inhibition of α-glucosidase has been demonstrated. However, little has been reported about the effect of pear on insulin signaling pathway in obesity. The aims of this study are to establish pear pomace 50% ethanol extract (PPE)-induced improvement of insulin sensitivity and characterize its action mechanism in 3T3-L1 cells and high-fat diet (HFD)-fed C57BL/6 mice. MATERIALS/METHODS Lipid accumulation, monocyte chemoattractant protein-1 (MCP-1) secretion and glucose uptake were measure in 3T3-L1 cells. Mice were fed HFD (60% kcal from fat) and orally ingested PPE once daily for 8 weeks and body weight, homeostasis model assessment of insulin resistance (HOMA-IR), and serum lipids were measured. The expression of proteins involved in insulin signaling pathway was evaluated by western blot assay in 3T3-L1 cells and adipose tissue of mice. RESULTS In 3T3-L1 cells, without affecting cell viability and lipid accumulation, PPE inhibited MCP-1 secretion, improved glucose uptake, and increased protein expression of phosphorylated insulin receptor substrate 1 [p-IRS-1, (Tyr632)], p-Akt, and glucose transporter type 4 (GLUT4). Additionally, in HFD-fed mice, PPE reduced body weight, HOMA-IR, and serum lipids including triglyceride and LDL-cholesterol. Furthermore, in adipose tissue, PPE up-regulated GLUT4 expression and expression ratio of p-IRS-1 (Tyr632)/IRS, whereas, down-regulated p-IRS-1 (Ser307)/IRS. CONCLUSIONS Our results collectively show that PPE improves glucose uptake in 3T3-L1 cells and insulin sensitivity in mice fed a HFD through stimulation of the insulin signaling pathway. Furthermore, PPE-induced improvement of insulin sensitivity was not accompanied with lipid accumulation.

Pepper Seed Extract Suppresses Invasion and Migration of Human Breast Cancer Cells

This study was performed to determine the antimetastatic activities of chili pepper seed on human breast cancer cells. The water extract of chili pepper seeds was prepared and it contained a substantial amount of phenols (131.12 mg%) and no capsaicinoids. Pepper seed extract (PSE) suppressed the proliferation of MDA-MB-231 and MCF-7 cells at the concentration of 10, 25, and 50 μg/ml (MDA-MB-231: IC50 = 20.1 μg/ml, MCF-7: IC50 = 14.7 μg/ml). PSE increased the expression level of E-cadherin up to 1.2-fold of the control in MCF-7 cells. PSE also decreased the secretion of matrix metalloproteinase (MMP)-2 and MMP-9 in MDA-MB-231 and MCF-7 cells at the concentration of 25 and 50 μg/ml. PSE treatment significantly suppressed the invasion of MDA-MB-231 and MCF-7 cells in a dose-dependent manner. The motility of cancer cells was apparently retarded in the wound healing assay by the PSE treatment. Although our data collectively demonstrate that PSE inhibits invasion and migration of breast cancer cells, further study is needed to identify specific mechanisms and bioactive components contributing to antimetastatic effects of chili pepper seed.

St. John’s Wort Regulates Proliferation and Apoptosis in MCF-7 Human Breast Cancer Cells by Inhibiting AMPK/mTOR and Activating the Mitochondrial Pathway

St. John’s Wort (SJW) has been used as an estrogen agonist in the systems affected by menopause. Also, hypericin, a bioactive compound of SJW, has been used as a photosensitizer in photodynamic therapy. In the present study, we investigate the anti-proliferative and pro-apoptotic effects of SJW to demonstrate the chemo-preventive effect in human breast cancer cells. MCF-7 cells were cultured with DMSO or various concentrations of SJW ethanol extract (SJWE). Cell viability, proliferation, apoptosis, the expression of proteins involved in cell growth and apoptosis, and caspase-3/7 activity were examined. SJWE dose-dependently suppressed cell growth and induced apoptosis of MCF-7 cells. Mechanistically, SJWE enhanced the phosphorylation of AMP-activated protein kinase (AMPK) and decreased the expression of p-mammalian target of rapamycin (p-mTOR) and p-eukaryotic translation initiation factor 4E (eIF4E)-binding protein 1 (4E-BP1). Also, SJWE inhibited the phosphorylation of protein kinase B (Akt) and showed increases in the expression of pro-apoptotic proteins Bax and Bad with decreases in the expression of anti-apoptotic proteins including B-cell lymphoma 2 (Bcl-2), B-cell lymphoma-extra large (Bcl-xL), and p-Bcl-2-associated death promoter (p-Bad). SJWE at 50 μg/mL showed markedly enhanced caspase-7 activation. Taken together, our results provide evidence that SJWE shows anti-proliferative and pro-apoptotic effects via inhibition of AMPK/mTOR and activation of a mitochondrial pathway. Therefore, SJWE can be used as a chemo-preventive agent without photo-activation.

Inhibitory effect of Erythronium japonicum on the human breast cancer cell metastasis

BACKGROUND/OBJECTIVES In this study, the inhibitory effect of Erythronium japonicum extracts on the metastasis of MDA-MB-231 human breast cancer cell line was determined. MATERIALS/METHODS Cells were cultured with DMSO or with 50, 75, 100 or 250 µg/ml of Erythronium japonicum methanol or ethanol extract. RESULTS Both methanol and ethanol extracts significantly inhibited the growth and induced apoptosis of MDA-MB-231 cells in a dose-dependent manner. Erythronium japonicum extracts inhibited the adhesion of MDA-MB-231 cells. The invasion of breast cancer cells was suppressed by Erythronium japonicum extracts in a dose-dependent manner. The motility and MMP-2 and MMP-9 activities were also inhibited by both methanol and ethanol extracts. CONCLUSIONS Our results collectively indicate that Erythronium japonicum extracts inhibit the growth, adhesion, migration and invasion as well as induce the apoptosis of human breast cancer cells. Clinical application of Erythronium japonicum as a potent chemopreventive agent may be helpful in limiting breast cancer invasion and metastasis.