• Nutrition Research and Practice
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• v.10 no.5
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• pp.507-515
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• 2016

BACKGROUND/OBJECTIVES: This study was designed to investigate whether Gynura procumbens extract (GPE) can improve insulin sensitivity and suppress hepatic glucose production in an animal model of type 2 diabetes. MATERIALS/METHODS: C57BL/Ksj-db/db mice were divided into 3 groups, a regular diet (control), GPE, and rosiglitazone groups (0.005 g/100 g diet) and fed for 6 weeks. RESULTS: Mice supplemented with GPE showed significantly lower blood levels of glucose and glycosylated hemoglobin than diabetic control mice. Glucose and insulin tolerance test also showed the positive effect of GPE on increasing insulin sensitivity. The homeostatic index of insulin resistance was significantly lower in mice supplemented with GPE than in the diabetic control mice. In the skeletal muscle, the expression of phosphorylated AMP-activated protein kinase, pAkt substrate of 160 kDa, and PM-glucose transporter type 4 increased in mice supplemented with GPE when compared to that of the diabetic control mice. GPE also decreased the expression of glucose-6-phosphatase and phosphoenolpyruvate carboxykinase in the liver. CONCLUSIONS: These findings demonstrate that GPE might improve insulin sensitivity and inhibit gluconeogenesis in the liver.

• Korean Journal of Food Science and Technology
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• v.47 no.5
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• pp.545-555
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• 2015

Oxyresveratrol (trans-2,3',4,5'-tetrahydroxystilbene) has been receiving increasing attention because of its astonishing biological activities, including antihyperlipidemic, neuroprotection, antidiabetic, anticancer, antiinflammation, immunomodulation, antiaging, and antioxidant activities. Oxyresveratrol is a stilbenoid, a type of natural phenol and a phytoalexin produced in the roots, stems, leaves, and fruits of several plants. It was first isolated from the heartwood of Artocarpus lakoocha, and has also been found in various plants, including Smilax china, Morus alba, Varatrum nigrum, Scirpus maritinus, and Maclura pomifera. Oxyresveratrol, an aglycone of mulberroside A, has been produced by microbial biotransformation or enzymatic hydrolysis of a glycosylated stilbene mulberroside A, which is one of the major compounds of the roots of M. alba. Oxyresveratrol shows less cytotoxicity, better antioxidant activity and polarity, and higher cell permeability and bioavailability than resveratrol (trans-3,5,4'-trihydroxystilbene), a well-known antioxidant, suggesting that oxyresveratrol might be a potential candidate for use in health functional food and medicine. This review focuses on the plant sources, chemical characteristics, analysis, biosynthesis, and biological activities of oxyresveratrol as well as describes the perspectives on further exploration of oxyresveratrol.

• Journal of Microbiology and Biotechnology
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• v.17 no.3
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• pp.539-542
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• 2007

Glycosyltransferase family 1 (UOT) uses small chemicals including phenolics, antibiotics, and alkaloids as substrates to have an influence in biological activities. A glycosyltransferase (XcGT-2) from Xanthomonas campestris was cloned and consisted of a 1,257 bp open reading frame encoding a 45.5 kDa protein. In order to use this for the modification of phenolic compounds, XcGT-2 was expressed in Escherichia coli as a glutathione S-transferase fusion protein. With the E. coli transformant expressing XcGT-2, biotransformation of flavonoids was carried out. Flavonoids having a double bond between carbons 2 and 3, and hydroxyl groups at both C-3' and C-4', were glycosylated and the glycosylation position was determined to be at the hydroxyl group of C-3', using nuclear magnetic resonance spectroscopy. These results showed that XcGT-2 regiospecifically transferred a glucose molecule to the 3'-hydroxyl group of flavonoids containing both 3' and 4'-hydroxyl groups.

• Archives of Pharmacal Research
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• v.14 no.2
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• pp.147-159
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• 1991

Effects of twenty-one different flavonoids and their related compounds on the phagocytosis of colloidal carbon by macrophages in liver and spleen humoral immune responses against bacterial $\alpha$-amylase and cellular immune responses against oxazolone and dinitrofluorobenzene were studied in vivo and in vitro. It was shown that most of the flavonoids accelerated significantly the phagocytosis, and they suppressed significantly not only humoral and cellular immune responses but also the development of immunological memory after the antigenic stimulation. Especially, malvin was the most active in phagocysis, and disodium cromoglycate and morin were the most active in humoral and cellular immunosuppression, respectively. Daidzuin had the most potent inhibitory activity in the development of memory cells. The structure-activity relationships of the flavonoids in immunosuppression became apparant from these results: 1. The presence of $C_{2-3}$ double bond and $C_4$ Ketone group in C-ring was important for their immunosuppressive activity. 2. Flavonoids with benzene ring at 2 or 3 position in C-ring showed the almost same activities. 3. The opening of C-ring did not affect their immunosuppressive activity. 4. The glycosylated flavonoids at 3 position in C-ring were less less potent than their aglycones. 5. Di-or tri-hydroxylated flavonoids in B-ring were more potent than mono-hydroxylated. 6. Chromanochromanone also had the immunosuppressive activity.

• Korean Journal of Microbiology
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• v.31 no.3
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• pp.203-207
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• 1993

Five different secretion vectors were constructed by varying the signal sequences and .alpha.-antitrypsin (.alpha.1-AT) a numan secretory protein, was produced from yeast cells. The signal sequences used are those of acid phosphatase (PH05) and .alpha.-factor (M f.alphal1) of Saccharomyces cerevisiae, glucoamylase (STA1) of Saccharomyces diastaticus, and human .alpha.1-AT. Four vectors directed the efficient secretion of .alpha.1-AT ito the culture media. The secretion vector carrying the glucoamylase signal sequence (pGAT11) showed the highest efficiency of secretion. About 70% of .alpha.1-AT produce dwere secreted into the media. The endo H treatment of partially purified .alpha.1-AT indicates that the secreted .alpha.1-AT appeared to be glycosylated. This glycosylation pattern was altered when amino acid substitution mutations were introduced at the three glycosylation sites of .alpha.-AT.

• Journal of Oral Medicine and Pain
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• v.22 no.2
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• pp.341-358
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• 1997

Clusterin is a highly glycosylated protein composed of two disulfide linked subunits. Although its biolobical action is not clearly defined, clusterin seems to be involved not only in remodeling of damaged tissue, but also in production of halitosis, the present study was designated to elucidate the expression of clusterin in the salivary gland of diabetic rats. For this study, 24 Sprague-Dawley rats were used for the experiment and divided into 2groups: control and experimental. The experimental group was composed of 18 rats and the control goup was 6 rats. After nduction of diabetes by STZ injection, the animals were sacrificed at 1,3,5,7,10,14 days. The parotid and submamndibular glands were observed histologically and the transcriptional expression of clusterin in the glands by Northern blot. The finding were as follows : 1. In experimental group, the salivary glands were observed at day 3 and then a seven destructive pattern was found in the glands at day 5. Howere, regeneration of gland tissue occured at day 14. 2. In experimental goup, destructive change was examined in the septal connective tissue after 7 days, and gradually more serious. 3. In experimental group, clusterin was expressed in the submandibular glands after 5 days, but in parotid glands to a lesser extent after 10 days. These results suggest that clusterin seems to be closely associated with histologic changes in the mucous glands rather serous glands.

• Advances in Traditional Medicine
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• v.5 no.2
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• pp.160-166
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• 2005

The present study was carried out to investigate the hypoglycemic effect of a polyherbal aqueous extract (Curcuma longa Linn., Emblica officinalis Gaertn., Trigonella foenum-graecum Linn., Enicostemma littorale Blume) in alloxan-induced diabetic rats. Short term experiments showed a decrease in blood glucose levels at $2^{nd}\;hr$ of administration of the aqueous extract in alloxan-induced diabetic rats with increase in serum insulin levels. The extract did not show any effect on blood glucose or serum insulin levels in normoglycaemic rats. Treatment with the extract (1.5 g dry plant equivalent extarct/100 g body weight/day) for 20 days in diabetic rats showed a significant decrease in blood glucose and glycosylated haemoglobin levels and an increase in serum insulin levels. The aqueous extract also showed an enhanced glucose-induced insulin release at 11.1 mM glucose from isolated rat pancreatic islets. The extract did not show any toxicity at the particular dose used.

• 한국인삼전략화협의회:학술대회논문집
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• v.2003 no.09
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• pp.54-63
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• 2003

"Korea ginseng (Panax ginseng C.A Meyer) is an important medicinal plant. Its root has been used as an herbal medicine that provides resistance to stress and disease, and prevents exhaustion since the ancient time. Ginsenosides, glycosylated triterpene (saponin), are considered to be the main active compounds of the ginseng root. Despite of considerable commercial interests of ginsenosides, very little is known about the genes and their biochemical pathways for ginsenoside biosynthesis. This work will focus on the identification of genes involved in ginsenoside biosynthesis and the dissection of ginsenoside biosynthetic pathway using a functional genomics tool. Expression sequence tags (ESTs) provide a valuable tool to discovery the genes in secondary metabolite biosynthesis. We generated over 21,155 ginseng ESTs that is now sufficient to facilitate discovering the genes involved in ginsenoside biosynthesis such as oxidosqualene cyclase(OSC), cytochrome P450 and glycosyltransferase. With ESTs information, microarray technology will be used for the analysis of gene expression, and the identification of genes including transcription factors expressed in tissues under given experimental condition. Heterogous system such as yeast and plants will allow us to do the functional analysis. And selected ginseng hairy root which show variation in ginsenoside production will be used as a material for functional analysis of candidate gene. Functional genomics approach will successfully accelerate gene discovery, and also provide promises of metabolic engineering for the ginsenoside production."

• BMB Reports
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• v.47 no.5
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• pp.256-261
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• 2014

To investigate the function of N-glycosylation of Cel5A (endoglucanase II) from Hypocrea jecorina, two N-glycosylation site deletion Cel5A mutants (rN124D and rN124H) were expressed in Saccharomyces cerevisiae. The weights of these recombinant mutants were 54 kDa, which were lower than that of rCel5A. This result was expected to be attributed to deglycosylation. The enzyme activity of rN124H was greatly reduced to 60.6% compared with rCel5A, whereas rN124D showed slightly lower activity (10%) than that of rCel5A. rN124D and rN124H showed different thermal stabilities compared with the glycosylated rCel5A, especially at lower pH value. Thermal stabilities were reduced and improved for rN124D and rN124H, respectively. Circular dichroism spectroscopy showed that the modification of secondary structure by mutation may be the reason for the change in enzymatic activity and thermal stability.

• Advances in Traditional Medicine
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• v.3 no.2
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• pp.84-89
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• 2003

The antidiabetic efficacy of Enicostemma littorale Blume (chhota chirayata) aqueous extract was examined in newly diagnosed non-insulin-dependent diabetes mellitus (NIDDM) patients taking only the extract and was administered as two divided doses, half an hour before meal as 5g of aqueous extract per single dose. Out of the 20 patients volunteered, 11 successfully completed the 2 month trial and a significant decrease in fasting & postprandial blood glucose and glycosylated haemoglobin levels were observed along with a significant improvement in the antioxidant parameters of the patients. There was also a significant increase in serum insulin levels in 7 patients after extract treatment as compared to levels before treatment. Serum total cholesterol and serum triglyceride levels were decreased significantly with a significant increase in serum HDLCholesterol levels. Other vital parameters remained stable and no side effects were observed. This is the first report showing the hypoglycemic, antioxidant and hypolipidemic properties of the aqueous extract of E. littorale Blume in non-insulin dependent diabetes mellitus patients.