• Biomolecules & Therapeutics
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• v.17 no.3
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• pp.256-262
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• 2009

Smallanthus sonchifolius (Yacon, Asteraceae) was originally cultivated in South America and used in food and traditional medicine by Andean inhabitants. Yacon is potentially beneficial for the management of diabetes and is composed of fructooligosaccharides, proteins, minerals and phenolic compounds. The aim of this study was to investigate the hypoglycemic effect of Yacon tuber extract (YTE) and its constituent, chlorogenic acid (CGA), in streptozotocin (STZ)-induced diabetic rats. In this study, a HPLC method was developed for simultaneous determination of major active phenolic components, CGA and caffeic acid in YTE. We investigated the hypoglycemic effect of YTE and CGA in STZ-induced diabetic rats and studied glucose tolerance test (GTT). The effect of orally administered multiple doses of YTE and CGA on plasma biochemical parameters was examined using diabetic rats. We also measured free radical scavenging activity by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. Oral administration of YTE (200 mg/kg) and CGA (10 mg/kg) for 6 weeks produced a significant hypoglycemic effect in STZ-induced diabetic rats. YTE and CGA-treated groups exhibited significantly decreased plasma glucose surge during the GTT. Total cholesterol (TC) and triglyceride (TG) concentrations were significantly decreased by 33% and 49%, respectively, in YTE-treated rats. TC and TG concentrations were also significantly decreased by 26 % and 41%, respectively, in CGA-treated rats. In the DPPH assay, free radical scavenging activity of CGA was similar to that of vitamin E, a positive control. This study suggests that YTE and its constituent, CGA, may be a useful option for management of hyperglycemia and diabetic nephropathy.

• Journal of Life Science
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• v.21 no.3
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• pp.435-443
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• 2011

The purpose of this study is to identify the effects of exercise training [ET, 10~18 m/min (speed), 20~30 min (exercise duration)/a day for 5 day/wk, 6 wk) on PGC-$1{\alpha}$, GLUT-1, Tfam, Cu,Zn-SOD and Mn-SOD proteins in brain of STZ-induced diabetic rats. The male Sprague-Dawley (SD) rats were single-injected intraperitoneally with 50mg/kg of streptozotocin (STZ) to produce STZ-induced diabetic rats. Rats were divided into 3 experimental groups with 8 rats in each group, as follows: (1) non-STZ group (n=8), (2) STZ-CON group (n=8), (3) STZ-EXE group (n=8). The results of this study suggest that i) serum glucose level was significantly reduced in STZ-EXE group compared with STZ-CON group (p<0.05), ii) PGC-$1{\alpha}$ (p<0.001), mtPGC-$1{\alpha}$ (p<0.001), GLUT-1 (p<0.001), and mtTfam (p<0.001) proteins in brain of STZ-induced diabetic rats were significantly increased in STZ-EXE group compared with STZ-CON group, iii) Cu,Zn-SOD (p<0.001) and Mn-SOD (p<0.01) proteins in the STZ-induced diabetic rats were significantly increased in STZ-EXE group compared with STZ-CON group. In conclusion, the findings of the present study reveal that treadmill exercise training increases brain GLUT-1 protein level possibly through up-regulation of PGC-$1{\alpha}$ and Tfam proteins which represent key regulatory components of stimulation of brain mitochondrial biogenesis. In addition, treadmill exercise training may prevent oxidative stress by up-regulation of Cu,Zn-SOD and Mn-SOD proteins in the STZ-induced diabetic rats.

• Journal of Acupuncture Research
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• v.18 no.5
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• pp.155-163
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• 2001

It has known that acupuncture exerts various effects, such as analgesia, promotion of homeostasis, improvements in brain circulation, and rectification of internal disorders in Oriental medicine. Of particular, acupuncture at the Zusanli acupoint (ST36) has been widely used to relieve symptoms of diabetes mellitus. The effect of acupuncture at Zusanli on neuronal nitric oxide synthase (nNOS)-positive neurons in streptozotocin (STZ)-induced diabetic rats was investigated via immunohistochemistry. Decreased nNOS-positive neurons was detected in cerebrocortex of STZ-induced diabetic rats. Needling on the Zusanli in diabetic rats resulted in increase of nNOS-positive neurons in cerebrocortex, The present study indicate that acupuncture may affect nNOS-positive neurons in cerebrocortex of STZ-induced diabetic rats.

• Journal of Nutrition and Health
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• v.34 no.6
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• pp.619-625
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• 2001

Diabetes mellitus was induced in male Sprague-Dawley rats weighing 200-245g by injection of streptozotocin(STZ) into the tail vein at a dose of 45mg/kg and were divided into seven groups ; normal, diabetic control, and five experimental groups(fractions of hexane, chloroform(CHCl$_3$), ethylacetate(EtOAc), butanol(BuOH) and water($H_2O$)). The rats of all groups were fed on AIN-93 diet and the five experimental groups were orally administered each fraction for 14 days. The body weight and diet intake were monitored daily. The plasma levels of glucose, insulin, cholesterol, triglyceride, HDL-cholesterol, free fatty acid and aspartate and alanine aminotransferase activities were analyzed. Diabetic rats showed the lower weight gain compared to the normal rats. The plasma glucose levels of the CHCl$_3$, and $H_2O$ fraction groups were significantly lower than the other experimental groups. The plasma insulin level of the CHCl$_3$ fraction group was much higher than that of diabetic control group. The plasma cholesterol levels were increased in all the experimental groups. The groups of hexane, BuOH and H2() fractions showed the lower plasma triglyceride levels compared to diabetic control group. The plasma free fatty acid levels were not significantly different in all groups. HDL-cholesterol levels were definitely higher in hexane, CHCl$_3$ and EtOAc fraction groups than that of diabetic control group. In conclusion, administration of CHCl$_3$ and $H_2O$ fractions of methanol extract of Alisma canaliculatum exhibited hypoglycemic effects in STZ induced diabetic rats, showing the possibility of therapeutic use of Alisma canaliculatum to the diabetes mellitus.

• The Korean Journal of Applied Statistics
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• v.22 no.1
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• pp.107-114
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• 2009

The present study was carried out to summarize the effect of ginseng in the experimental diabetic rats by meta-analysis related studies. The association measure to test effect of ginseng was the mean difference(MD) between group of rats induced streptozotocin(STZ) and group of rats induced STZ treated with ginseng about the considered effect factors. The level of FI, glucose and TG were significantly reduced(< 0.01), and the level of glycogen was significantly increased by treatment with ginseng (< 0.01) After checking the indication of publication bias for the combined MDs by using the funnel plots, the anti-diabetic effects of ginseng is clearly presented in FI, glucose, TG and glycogen (< 0.05).

• The Korean Journal of Food And Nutrition
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• v.23 no.2
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• pp.258-268
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• 2010

This study was conducted to examine the hypoglycemic effects of complexcity extract(DB 55) from five oriental medicinal plants on the intake of food, body weight, blood glucose level, insulin content, serum GOP, GPT, BUN and hematocrit value in streptozotocin(STZ)-induced diabetic rats. General nutritional composition was also assessed. Thirty- five male Sprague-Dawley rats were assigned to five groups : normal control group(NC), STZ-diabetic control group (STZ-control), STZ-diabetic DB-1 group(DB 55-1), STZ-diabetic DB-2 group(DB 55-2) and STZ-diabetic DB-3 group(DB 55-3). The animals were fed an experimental diet for 12 weeks. Body weight gain of the STZ-diabetic group was significantly lower but diet intake was significantly higher than the NC group. Blood glucose levels of the DB-1, DB-2 and DB-3 rats were significantly lower than the STZ-control animals. Insulin level of STZ-control rats was lower than the NC serum GOT, GPT and BUN levels were significantly higher in the NC group, but hematocrit value was not significant as compare to the STZ-diabetic group. Blood glucose level was lower observed for the DB 55-1, DB 55-2 and DB 55-3 group. The results will be useful in oriental diet therapy and in the developing functional food resources.

• Journal of Acupuncture Research
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• v.20 no.3
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• pp.1-14
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• 2003

Objective : The aim of the study was to investigate the preventive effect of Acanthopanax senticosus(AS) aqua-acupuncture into Sinsu(BL23) of the multiple low-does strepozotocin(STZ)-induced diabetic rats. Methods : The experimental animals were divided into 4 groups : normal group of rats, control group of multiple low-does STZ-induced diabetic rats, NSAA group with 0.4ml normal saline(NS) aqua-acupunctured subcutaneously into Sinsu in multiple low-does STZ-induced diabetic rats, and ASAA group with 0.4ml of 20% AS aqua-acupunctured subcutaneously into Sinsu in multiple low-does STZ-induced diabetic rats. Each of AS and NS aqua-acupuncture was done subcutaneously into both loci of Sinsu taking turns everyday for 3 weeks. Thereafter the levels of serum glucose, body weight, index of kidney hypertrophy, urine glucose, urinary albumin excretion, creatinine clearance, mesangial cell and TGF-${\beta}1$ expression in glomeruli and tubular cells were measured on the determined day. Conclusions : 1. Both ASAA and NSAA groups decreased the serum glucose levels in multiple low-dose STZ-induced diabetic rats as compared to the cintrol group, and ASAA group showed more significant decreases than NSAA group. 2. Both ASAA and NSAA groups prevented the development of diabetes in multiple low-dose STZ-induced diabetic rats as compared to the control group, and ASAA group prevented more markedly the development of diabetes than NSAA group. 3. Both ASAA and NSAA groups prevented the reduction of body weight in multiple low-dose STZ-induced diabetic rats as compared to the control group, and ASAA group showed the same as the normal group. 4. Both ASAA and NSAA groups did not show any changes of the creatinine clearance in multiple low-does STZ-induced diabetic rats. 5. Both ASAA and NSAA groups prevented the excretion of urinary glucose and albumin in multiple low-dose STZ-induced diabetic rats as compared to the cintrol group, and ASAA group showed more significant prevention than NSAA group. 6. Both ASAA and NSAA groups prevented the expansion of glomerular cells and the protein expression of transforming growth factor-${\beta}1$ in multiple low-dose STZ-induced diabetic rats as compared to the cintrol group, and ASAA group prevented more significantly than NSAA group.

• Nutrition Research and Practice
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• v.3 no.3
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• pp.242-246
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• 2009

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.

• Food Science and Preservation
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• v.21 no.4
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• pp.549-559
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• 2014

This study investigated the hypoglycemic effects of mulberry leaf (M), green tea (G), and a mixture of mulberry leaf and green tea (MG) in rats with streptozotocin-induced diabetes. Male Sprague-Dawley rats were divided into the non-diabetic (N) and diabetic groups. The experimental animals were divided into four groups and fed the following for four weeks: a normal diet (N), the STZ+normal diet (STZ), the STZ+5% mulberry leaf (STZ-M), STZ+5% green tea (STZ-G), and the STZ+5% mixture of mulberry leaf and green tea (STZ-MG). The whole blood glucose level of the STZ-M, STZ-G and STZ-MG groups significantly decreased compared to the STZ group two weeks later. The serum glucose and fructosamine, and urine glucose levels in the STZ-M, STZ-G and STZ-MG groups were lower than in the STZ group. The levels of serum insulin were higher in the STZ-M, STZ-G and STZ-MG groups than in the STZ group. However, serum glucose, fructosamine and insulin levels, and urine glucose levels were not significantly different among the STZ-M, STZ-G and STZ-MG groups. These results indicate that mulberry leaf, green tea, and their mixture help prevent or attenuate the progression of diabetes in rats with STZ-induced diabetes.

• The Korean Journal of Physiology and Pharmacology
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• v.9 no.5
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• pp.305-314
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• 2005

Diabetes mellitus is associated with vascular complications, including an impairment of vascular function and alterations in the reactivity of blood vessels to vasoactive substances in various vasculature. In the present study, the authors have observed endothelin-B ($ET_B$) receptor agonist-induced relaxation in precontracted mesenteric arterial segments from streptozotocin (STZ)-induced diabetic rats, which was not shown from control rats or in other arterial segments from diabetic rats. Accordingly, the goal of this study was to investigate in what way STZ-induced diabetes altered reactivity of the mesenteric arterial bed and to examine the causal relaxation, if any, between this $ET_B$ receptor-mediated relaxation and endothelial paracrine function, especially nitric oxide (NO) production. The relaxation induced by $ET_B$ agonists was not observed in mesenteric arteries without endothelium. The relaxation to $ET_B$ agonists was completely abolished by pretreatment with BQ788, but not by BQ610. $N_{\omega}-nitro-L-arginine$ methyl ester and soluble guanylate cyclase inhibitors, methylene blue or LY83583 significantly attenuated the relaxant responses to $ET_B$ agonists, respectively. When the expression of eNOS and iNOS was evaluated on agarose gel stained with ethidium bromide, the expression of eNOS mRNA in diabetic rats was significantly decreased, but the expression of iNOS was increased compared with control rats. Furthermore, the iNOS-like immunostaining was densely detected in the endothelium and slightly in the arterial smooth muscle of diabetic rats, but not in control rats. These observations suggest that $ET_B$ receptor may not play a role in maintaining mesenteric vascular tone in normal situation. However, the alterations in $ET_B$ receptor sensitivity were found in diabetic rats and lead to the $ET_B$ agonist-induced vasorelaxation, which is closely related to NO production. In the state of increased vascular resistance of diabetic mesenteric vascular bed, enhanced NO production by activation of iNOS could lead to compensatory vasorelaxation to modulate adequate perfusion pressure to splanchnic area.