• Natural Product Sciences
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• v.14 no.4
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• pp.260-264
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• 2008

To find the antidiabetic activity of the tripterpenoid-rich fractions of Rubus coreanus (TRF-cor) and R. crataegifolius (TRF-cra) leaves or its main component niga-ichigoside $F_1$ (Niga-$F_1$), anti-hyperglycemic and antihyperlipidemic effects were investigated in the diabetic rat model induced by streptozotocin (STZ). Treatments of rats with 200 mg/kg of the TRF-cor, TRF-cra (each, p.o.) or 20 mg/kg of Niga-$F_1$ significantly inhibited the increase of blood glucose concentration about 44.8%, 28.7% or 20.6%, respectively, in the diabetic rats. In addition, treatments with those fractions inhibited the increase of serum concentrations of triglyceride, total cholesterol or LDL-cholesterol caused by STZ. The inhibitory rate on atherogenic index (AI) values of the TRFcor (200 mg/kg), TRF-cra (200 mg/kg) or Niga-$F_1$ (20 mg/kg)-treated groups were decreased about 55.7%, 36.3% or 22.6%, respectively, comparable to STZ-treated group. In the oral glucose tolerance test, treatment of TRF-cor or TRF-cra inhibited the increase of blood glucose concentration in the STZ-induced rats. Administration of 20 mg/kg of Niga-$F_1$ (p.o.) also exhibited similar effects with the effects of both TRFs at 200 mg/kg dose (p.o.). These results support that the triterpenoids, in particular Niga-$F_1$, are contributed to the antidiabetic effects of R. coreanus or R. crataegifolius.

• Journal of Life Science
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• v.16 no.2 s.75
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• pp.259-265
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• 2006

This study is investigated the effect on mechanism of nephrotoxicity formation of methotrexate(MTX) by hyperglycemic by streptozotocin(STZ). MTX was injected daily at two doses of 3, 6 mg/kg for 1 week in STZ-induced hyperglycemic rats. Activities of BUN, creatinine and LDH were significantly increased by treatment with MTX in STZ-induced diabetic group when compared to MTX treatment group in normal rats' Renal lipid peroxide content and activities of cytosolic enzyme were significantly increased in the treatment of MTX in diabetic group. The concentration of glutathione and glutathione biosynthesis enzymes were decreased by treatment with MTX in STZ-induced diabetic group. These results suggest that nephrotoxicity of MTX in STZ-induced hyperglycemic rat was caused by activation of renal metabolizing enzymes in cytosol and decrease of glutathione concentration.

• Biomolecules & Therapeutics
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• v.22 no.1
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• pp.47-54
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• 2014

The present study was aimed to evaluate the antioxidant defense system of cinnamaldehyde in normal, diabetic rats and its possible protection of pancreatic ${\beta}$-cells against its gradual loss under diabetic conditions. In vitro free radical scavenging effect of cinnamaldehyde was determined using DPPH (1,1-diphenyl-2-dipicrylhydrazyl), superoxide radical, and nitric oxide radical. Streptozotocin (STZ) diabetic rats were orally administered with cinnamaldehyde at concentrations of 5, 10 and 20 mg/kg body weight for 45 days. At the end of the experiment, the levels of plasma lipid peroxides and antioxidants such as vitamin C, vitamin E, ceruloplasmin, catalase, superoxide dismutase, reduced glutathione and glutathione peroxidase were determined. A significant increase in the levels of plasma glucose, vitamin E, ceruloplasmin, and lipid peroxides and significant decrease in the levels of plasma insulin and reduced glutathione were observed in the diabetic rats. Also the activities of pancreatic antioxidant enzymes were altered in the STZ-induced diabetic rats. The altered enzyme activities were reverted to near-normal levels after treatment with cinnamaldehyde and glibenclamide. Histopathological studies also revealed a protective effect of cinnamaldehyde on pancreatic ${\beta}$-cells. Cinnamaldehyde enhances the antioxidant defense against reactive oxygen species produced under hyperglycemic conditions and thus protects pancreatic ${\beta}$-cells against their loss and exhibits antidiabetic properties.

• Korean Journal of Pharmacognosy
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• v.25 no.3
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• pp.264-271
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• 1994

Pharmacological effects of water extracts of Lycii Fructus, Lycii Folium and Lycii Cortex Radicis from Lycium chinensis were investigated. Lycii Folium significantly protected the hepatic function from damages orally caused by $CCl_4 $administration in mice and had a strong hypoglycemic effect in hyperglycemic mice induced by streptozotocin. Lycii Fructus decreased the blood pressure rise associated with the growth of normal rats. Lycii Cortex Radicis had a strong hypoglycemic effect in hyrerglycemic mice induced by streptozotocin. Also, hypolipidemic effects in hyperlipidemic rats induced by 1% cholesterol fed-diet and 75% fructose were significantly observed by oral administration of water extracts of Lycii Fructus, Lycii Folium and Lycii Cortex Radicis.

• Journal of Pharmacopuncture
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• v.16 no.3
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• pp.23-29
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• 2013

Objectives: Dyslipidemia in diabetes mellitus is a significant risk factor for the development of cardiovascular complications. The aim of this study was to evaluate the effect of the ethyl-acetate fraction of an ethanolic extract from Streospermum suaveolens on lipid metabolism in streptozotocin (STZ)-induced diabetic rats. Methods: Diabetes was induced by intraperitonial injection of STZ (50 mg/kg). Diabetic rats were treated with an ethyl-acetate fraction orally at doses of 200 and 400 mg/kg daily for 14 days. On the $15^{th}$ day, serum lipid profiles, such as total cholesterol (TC), triglycerides (TG), low-density lipoprotein (LDL), and high-density lipoprotein (HDL), were estimated in experimental rats. The atherogenic (AI) and the coronary risk (CRI) indices were also evaluated. Results: The ethyl-acetate fraction at doses of 200 and 400 mg/kg significantly (P < 0.001) and dose-dependently reduced serum cholesterol, triglycerides and LDL, but increased HDL towards near normal levels as compared to diabetic control rats. The fraction also significantly (P < 0.001) lowered the atherogenic index (AI) and coronary risk index (CAI) in a dose-dependent manner. Conclusion: The present study demonstrated that the ethyl-acetate fraction of Stereospermum suaveolens exhibits a potent antihyperlipidemic activity in hyperglycemic rats and suggests that the plant may have therapeutic value in treating the diabetic complication of hyperlipidemia.

• Journal of the East Asian Society of Dietary Life
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• v.18 no.4
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• pp.516-523
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• 2008

The effects of pan-fired (PM) and fermented (FM) Cudrania tricupidata tea leaves on $\alpha$-glucosidase inhibitory activity, oral glucose tolerance, blood glucose levels and serum lipids profiles in streptozotocin (STZ)-induced hyperglycemic rats were investigated. The $\alpha$-glucosidase inhibitory activity of FM ethanol extracts (20 mg/mL) was higher (92.5%) than that of raw dried leaves (RM) (69.1%) and PM (54.6%). In addition, the results of a glucose tolerance test revealed that the glucose levels of hyperglycemic rats that were fed PM and FM ethanol extracts and then orally administered glucose began to decrease after 60 minutes, but recovered after 120 minutes. However, the blood glucose levels in the hyperglycemic control group did not begin to decrease for 360 minutes. Additionally, the results of animal experiments that were conducted over five weeks to compare the dietary effects of PM and FM following hyperglycemic induction to the effects on the hyperglycemic control group (DM) were as follows: The body weight gain and FER of the treated rats were $12.9{\sim}16.9%$ higher than those of the DM group, whereas the amounts of feed and water intake by the treated rats were $6.8{\sim}10.1%$ lower. Additionally, the levels of blood glucose and serum fructosamine decreased by $27.3{\sim}39.8%$ and $6.7{\sim}20.0%$, respectively, in the treated rats. Moreover, the serum triglyceride, total cholesterol and LDL-cholesterol concentrations in the treated rats were $24.9{\sim}27.1%$, $15.9{\sim}17.4%$ and $33.8{\sim}38.4%$ lower, respectively. Finally, the HDL-cholesterol contents were $20.5{\sim}24.8%$ higher in the treated rats than in the control group. The above results suggest that PM and FM exerts an anti-hyperglycemic effect that occurs due to the inhibition of $\alpha$-glucosidase activity as well as via prevention and/or inhibition of changes in the serum lipid profile. In addition, the results of this study revealed that the synthetic anti-hyperglycemic effect of FM was greater than that of PM. However, further detailed studies are needed to confirm these results.

• The Korean Journal of Pharmacology
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• v.24 no.1
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• pp.125-134
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• 1988

A single i.v. dose of streptozotocin (65 mg/kg) given to rats has produced a marked hyper-glycemia (>500 mg serum glucose/dl). Since the Atractylodis Rhizoma is known to have hypo-glycemic action, the water extracts of Atractylodis Rhizoma (ARWE) was given to the streptozotocin-induced (SZ) hyperglycemic rats. To determine whether ARWE has the anti-hyperglycemic effects, two different daily doses of ARWE (i.e.0.2 g/kg and 2.0 g/kg) were given orally to the SZ rats for up to 8 days. Thereupon, serum levels of glucose, insulin, amylase and cholesterol were determined on days 1, 3 and 8, following the initial and repeated daily administrations of ARWE. On day 8, glycogen content and glucose-6-phosphatase activity in the liver were assayed. Results showed that ARWE decreased the serum glucose levels, which had been markedly elevated by the SZ pre-treatment. In support of this, the serum insulin level, which had been quickly lowered by the SZ pre-treatment $(20{\mu}U/ml)$, was quickly elevated in the ARWE dose dependent manner that, at 2.0 g/kg ARWE, the serum insulin level was increased $(20{\mu}U/ml)$ above the normal level $(42{\mu}U/ml)$. Also, the serum amylase level, which was steadily decreasing after the SZ pre-treatment, was restored to the normal level folowing 8 day of ARWE (2.0 g/kg) treatment. Hepatic glycogen content and glucose-6-phosphatase activity, which decreased and increased, respectively in the 52 treatment group, were restored toward the normal level in SZ plus ARWE group.

• Mycobiology
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• v.45 no.3
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• pp.199-203
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• 2017

This study was done to produce ${\gamma}$-aminobutyric acid (GABA) from wild yeast as well as investigate its anti-hyperglycemic effects. Among ten GABA-producing yeast strains, Pichia silvicola UL6-1 and Sporobolomyces carnicolor 402-JB-1 produced high GABA concentration of $134.4{\mu}g/mL$ and $179.2{\mu}g/mL$, respectively. P. silvicola UL6-1 showed a maximum GABA yield of $136.5{\mu}g/mL$ and $200.8{\mu}g/mL$ from S. carnicolor 402-JB-1 when they were cultured for 30 hr at $30^{\circ}C$ in yeast extract-peptone-dextrose medium. The cell-free extract from P. silvicola UL6-1 and S. carnicolor 402-JB-1 showed very high anti-hyperglycemic ${\alpha}$-glucosidase inhibitory activity of 72.3% and 69.9%, respectively. Additionally, their cell-free extract-containing GABA showed the anti-hyperglycemic effect in streptozotocin-induced diabetic Sprague-Dawley rats.

• Korean Journal of Pharmacognosy
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• v.31 no.2
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• pp.163-167
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• 2000

Cordyceps is reputed for its broad biological activities and as a tonic for replenishing vital function in Chinese traditional medicines. As an attempt to obtain fundamental data for the development of a new type Cordyceps, the effects of the fruiting bodies of cultivated fungus of Paecilomyces japonica grown on silkworm larvae on hyperglycemia induced by streptozotocin(STZ) and by epinephrine in rats and in mice as well as on immunological functions in mice were investigated. The 70% methanol extract of the fungus, when administered orally at 100 and 300 mg/kg in STZ-induced hyperglycemic rats, caused a significant decrease in blood glucose level 3hr after sample treatments. The methanol extract, when administered p.o. at the same dose levels in epinephrine-induced hyperglycemic mice, also caused a significant decrease in serum glucose levels as well as a significant reversal of the liver glycogen contents suggesting its hypoglycemic activity might be due to glycogen breakdown in the liver. Treatment of normoglycaemic mice with the methanol extract of the fungus exhibited a significant glucose tolerance up to 3hr after oral glucose load(2.0 g/kg). The methanol extract also showed immuno-stimulating activity as measured by carbon clearance in mice and a significant antifatigue effect as measured by weight loaded forced swimming performance in mice.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.2
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• pp.117-123
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• 1992

The present study was undertaken in order to elucidate the effects of pretreatment with nicotinamide on changes in serum glucose level, body weight, water consumption, serum insulin concentration, and the activity of pancreatic enzyme in rats treated with streptozotocin (STZ). Histological studies were also carried out to evaluate the effects on pancreatic tissues and Langerhans's islet cells. Nicotinamide pretreatment in STZ diabetic rats inhibited the rise of fasting serum glucose concentration and water consumption. Pretreatment with nicotinamide significantly increased the concentration of serum insulin and body weight changes compared to the STZ-treated group. Pancreatic lipase and trypsin activities were increased, but amylase activity was decreased and pancreatic $\beta$ -cell was destroyed by STZ. Pvetreatment with nicotinamide prevented these STZ-induced changes. These results suggest that nicotinamide pretreatment supresses STZ-induced changes in pancreatic enzymes by preventing $\beta$-cell destruction and therefore maintaining a normal serum insulin revel.