• 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.

• Advances in Traditional Medicine
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• v.5 no.1
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• pp.1-15
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• 2005

Ginseng is a popular medicinal plant highly valued throughout the world. Asian ginseng is one of the most common species of ginseng. It has long occupied a significant position in oriental medicine and has been justified its name as the 'king herb'. As a nutritional supplement, ginseng is an extremely common and popular herbal medicine in the United States and Canada in recent decades. The multiple constituents of ginseng possess equally multifaceted pharmacological actions as demonstrated by numerous studies. Ginseng root and its constituents influenced the central nervous system, endocrine, cardiovascular, gastrointestinal system, sexual, renal organ and immune system, etc. One important action is its anti-hyperglycemic effect. Previous studies on ginseng demonstrate that only the root of ginseng has been used in the treatment of diabetes, while the other parts of ginseng plant were always neglected. Recently, we analyzed the constituents of ginseng berry, leaf and discovered that ginseng berry, leaf extracts and its total ginsenosides have the ability to reduce hyperglycemia and body weight and increase the peripheral glucose utilization in obese or diabetic ob/ob or db/db mice. Our data suggest that all parts of ginseng plant, including root, berry, leaf and stem exhibit potent anti-hyperglycemic and anti-obese effects and may provide an opportunity to develop a novel class of anti-diabetic agents.

• Nutrition Research and Practice
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• v.7 no.1
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• pp.15-21
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• 2013

Leaf of Sasa borealis, a species of bamboo, has been reported to exhibit anti-hyperglycemic effect. However, its antidiabetic mechanism is not fully understood. In this study, we examined whether an extract of S. borealis activates AMP-activated protein kinase (AMPK) and exerts anti-hyperglycemic effects. Treatment with the S. borealis extract increased insulin signaling and phosphorylation of AMPK and stimulated the expression of its downstream targets, including $PPAR{\alpha}$, ACO, and CPT-1 in C2C12 cells and $PPAR{\alpha}$ in HepG2 cells. However, inhibition of AMPK activation attenuated insulin signaling and prevented the stimulation of AMPK target genes. The S. borealis extract increased glucose uptake in C2C12 cells and suppressed expression of the gluconeogenic gene, PEPCK in HepG2 cells. The extract significantly reduced blood glucose and triglyceride levels in STZ-induced diabetic mice. The extract enhanced AMPK phosphorylation and increased Glut-4 expression in the skeletal muscle of the mice. These findings demonstrated that the S. borealis extract exerts its anti-hyperglycemic effect through activation of AMPK and enhancement of insulin signaling.

• Advances in Traditional Medicine
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• v.8 no.3
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• pp.302-310
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• 2008

Azadirachta indica A. Juss (N.O. Meliaceae), popularly known, as 'Neem' is an indigenous tree widely available in India. Almost every part of the tree has long been used in Unani system of medicine for the treatment of a variety of human ailments. The flowers have been mentioned as a remedy useful in controlling diabetes mellitus. The present study had been designed to investigate the hypoglycemic/anti-hyperglycemic effects of the methanolic extract of the flowers of A. indica (Gule-Neem) and its different fractions on normal, glucose fed hyperglycemic, adrenaline induced hyperglycemic and alloxan induced diabetic rats. The methanolic extract was resolved into water soluble and water insoluble fractions. Water soluble portion of the methanolic extract was found to possess significant blood sugar lowering effect in glucose-fed and adrenaline-induced hyperglycemic rats but it did not show such effect in normal and alloxan induced mild and severe diabetic rats. Water-soluble portion was fractionated by employing the polarity criterion with ethyl acetate and butanol. The ethyl acetate fraction was further fractionated into phenolic and non-phenolic fractions. Hypoglycemic effect of these fractions was also evaluated. The results suggest that the flowers of A. indica contain at least two different constituents, responsible for the said activity. These investigations validate the use of flowers of A. indica in diabetes by Unani physicians.

• BMB Reports
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• v.40 no.5
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• pp.670-677
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• 2007

Although polysaccharide is believed to play an important role in the medicinal effect of Dendrobium chrysotoxum Lindl (DCL), its role as an antioxidant and in anti-hyperglycemic induction was not reported. In this study, polysaccharide with molecular weight of approximately 150 kDa, herein named DCLP, was isolated from the stem of DCL, and its antioxidative, hypoglycemic and immune stimulating effects were evaluated using various in vitro and in vivo assay systems. DCLP inhibited hydroxyl radicals ($^{\cdot}$OH)-mediated deoxyribose degradation by scavenging hydroxyl radicals directly as well as by chelating iron ions. DCLP also showed dose-dependent scavenging activity on superoxide anions ($O_2^{{\cdot}-}$) and offered significant protection (p < 0.001) against glucose oxidase-mediated cytotoxicity in Jurkat cells. DCLP had immune stimulating effects, as evidenced by the DCLP-mediated increases in the level of DNA synthesis, viability, and cytokine secretion in mouse lymphocytes. Moreover, oral administration of DCLP produced a significant reduction in blood glucose level in alloxan-induced diabetic mice. These findings suggest that DCLP has a potential utility in treating patients who require enhanced antioxidation, immune function and/or hypoglycemic activity.

• Korean Journal of Pharmacognosy
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• v.36 no.4 s.143
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• pp.291-298
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• 2005

Anti-hyperglycemic effects of 17 medicinal plants that have been used for ameliorating diabetes in oriental medicine were evaluated using glucose transport assay in 3T3-L1 adipocytes. Higher activities were obtained by treating water or alcohol extract of Phellodendri Cortex (PC), which showed enhancing effects both on basal and insulin-stimulated glucose uptake. The latter effect of PC was completely inhibited by wortmannin, a specific inhibitor for phosphatidyl inositol 3-kinase (PI 3-kinase), but not affected by SB203580, A specific inhibitor for p38 mitogen-activatedprotein kinase(MAPK). Genistein, an inhibitor for tyrosine kinases, abolished the PC effects completely. Treatment of vanadate, an inhibitor for tyrosine phosphatases, together with PC showed no significant synergic enhancement in glucose uptake. The results of inhibitors associated with insulin signaling pathway indicated that extracts of PC enhance glucose uptake by PI-3 kinase activation which is an upstream event for GLUT4 translocation. Antidiabetic effects of PC extract might be also due to enhanced tyrosine phosphorylation and reduced tyrosine dephosphorylation. In addition, PC accelerated insulin-stimulated glucose uptake in insulin-resistant cells, recovering the uptake level close to that of normal cells. These findings may offer a new way to utilize extracts of PC as novel anti-hyperglycemic agents.

• 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 Physiology and Pharmacology
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• v.20 no.6
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• pp.581-593
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• 2016

The advantages of monounsaturated fatty acids (MUFAs) on insulin resistance and type 2 diabetes mellitus (T2DM) have been well established. However, the molecular mechanisms of the anti-diabetic action of MUFAs remain unclear. This study examined the anti-hyperglycemic effect and explored the molecular mechanisms involved in the actions of fish oil- rich in MUFAs that had been acquired from hybrid catfish (Pangasius larnaudii${\times}$Pangasianodon hypophthalmus) among experimental type 2 diabetic rats. Diabetic rats that were fed with fish oil (500 and 1,000 mg/kg BW) for 12 weeks significantly reduced the fasting plasma glucose levels without increasing the plasma insulin levels. The diminishing levels of plasma lipids and the muscle triglyceride accumulation as well as the plasma leptin levels were identified in T2DM rats, which had been administrated with fish oil. Notably, the plasma adiponectin levels increased among these rats. The fish oil supplementation also improved glucose tolerance, insulin sensitivity and pancreatic histological changes. Moreover, the supplementation of fish oil improved insulin signaling ($p-Akt^{Ser473}$ and p-PKC-${\zeta}/{\lambda}^{Thr410/403}$), $p-AMPK^{Thr172}$ and membrane GLUT4 protein expressions, whereas the protein expressions of pro-inflammatory cytokines (TNF-${\alpha}$ and nuclear NF-${\kappa}B$) as well as p-PKC-${\theta}^{Thr538}$ were down regulated in the skeletal muscle. These data indicate that the effects of fish oil-rich in MUFAs in these T2DM rats were partly due to the attenuation of insulin resistance and an improvement in the adipokine imbalance. The mechanisms of the anti-hyperglycemic effect are involved in the improvement of insulin signaling, AMPK activation, GLUT4 translocation and suppression of pro-inflammatory cytokine protein expressions.

• Journal of the East Asian Society of Dietary Life
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• v.12 no.5
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• pp.364-369
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• 2002

Mulberry leaves are believed to be a potent inhibitor of intestinal $\alpha$-glycosidase and the digestion of sucrose in the small intestine. Mulberry leaves are also blown to help prevent the postprandial hyperglycemia. The objective of this study was to elucidate the functionality and anti-hyperglycemic effect of mulberry leaves, and to develop a functional drink using mulberry leaf, silk peptide and oriental medicine. Several mixtures of mulberry lear extract silk peptide and oriental medicine were made for the purpose of manufacture and formulation of products. These mixtures were tested to check the $\alpha$-glycosidase inhibition effect to find the best formula. The optimum conditions for a mulberry leaf hot water extract were that the size of leaf was under 3mm, the amount of leaf needed 50~100 g/L, extraction temperature 9$0^{\circ}C$ and extraction time 2 hr. The yield of extraction was 20~25%. The anti-hyperglycemic effect of mulberry leaves was at maximum when the concentrations of mulberry leaf extract and silk peptide were 1% and 0.1%, respectively.

• Natural Product Sciences
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• v.9 no.4
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• pp.291-298
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• 2003

Anti-diabetic effect of various fractions of Cordyceps militaris (CM), CCCA (crude cordycepin containing adenosine), CMESS (ethanol soluble supernatant), and cordycepin were evaluated in streptozotocin (STZ) induced diabetic mice, CMESS showed potent inhibitory activity of 34.7% in starch-loaded mice (2 g/kg) while acarbose as a positive standard exhibited 37.8% of inhibition rate. After 3 days administration (50 mg/kg), cordycepin (0.2 mg/kg), and acarbose (10 mg/kg) dramatically reduced blood glucose level (inhibition ratio: 46.9%, 48.4% and 37.5% respectively). CCCA that has high contents of cordycepin (0.656 mg/4 mg) did not influence on reducing blood glucose level. The proliferation of splenocytes and peritoneal macrophages derived from STZ-induced diabetic mice administered samples were evaluated out by addition of mitogens to see the stability of the usage of these herbal medicines. Proliferation of T-lymphocyte was significantly decreased; while NO production was increased more than two fold to STZ control in the cordycepin-administered group. Changes of serum enzyme levels of glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) were also evaluated. Cordycepin administered group was appeared to acarbose. We conclude that CMESS and cordycepin may be useful tools in the control of blood glucose level in diabetes and promising new drug as an anti-hyperglycemic agent without defects of immune responses and other side effects.