• International Journal of Industrial Entomology and Biomaterials
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• v.23 no.1
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• pp.123-128
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• 2011

1-Deoxynojirimycin (DNJ) is an alkaloid that is found at relatively high concentrations in mulberry leaf and tissues of the silkworm, $Bombyx$ $mori$. DNJ is a well known inhibitor of ${\alpha}$-glucosidase, an enzyme that is involved in the early stages of the $N$-linked glycoprotein synthesis pathway. ${\alpha}$-Glucosidase activity in the cell extract from $B.$ $mori$-derived Bm5 cells showed approximately 40-fold less sensitivity to DNJ than ${\alpha}$-glucosidase activity in the cell extract from $Spodoptera$ $frugiperda$-derived Sf9 cells. The replication of $B.$ $mori$ nucleopolyhedrovirus (BmNPV) was not inhibited when it was propagated in BmN cells that were grown in medium containing up to 10 mM DNJ. In contrast, the replication of $Autographa$ $californica$ multiple NPV (AcMNPV) was reduced by 67% when it was propagated in Sf9 cells that were grown in medium containing 10 mM DNJ. The viability of Bm5 and Sf9 cells that were grown in medium containing up to 10 mM DNJ was not affected. Our results suggested that the reduced replication of AcMNPV was the result of the higher sensitivity of ${\alpha}$-glucosidase activity in Sf9 cells to DNJ.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.11
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• pp.1401-1407
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• 2008

1-Deoxynojirimycin (DNJ) is a strong $\alpha$-glucosidase inhibitor which inhibits hyperglycemia in animals. To select the Bacillus strains highly producing DNJ, 4,000 strains were isolated from soil and grain samples. By the inhibitory activity against $\alpha$-glucosidase, nine Bacillus strains were selected and then identified by 16S rDNA sequencing. B. subtilis S10 was finally selected as the best strain for the production of DNJ. Various carbon sources and nitrogen sources in culture medium were evaluated for the highest production of DNJ. As the results, the optimized concentration of carbon source and nitrogen source was 1.0% galactose and 1.6% polypeptone and the concentration of DNJ produced was 0.75 g/L. The effect of culture supernatant of B. subtilis S10 on lowering blood glucose level was investigated in streptozotocin (STZ)-induced diabetic mice model. Mice were randomly assigned to control group (saline) and three test groups such as acarbose group, silkworm powder group and B. subtilis S10 group. After eight-week oral feeding, blood glucose levels of the B. subtilis S10 and silkworm powder groups were respectively $209.1{\pm}19.6\;mg/dL$ (59.1%) and $208.6{\pm}39.8\;mg/dL$ (59.0%) lower than $510{\pm}10\;mg/dL$ of the control group. These results indicated that the culture supernatant of B. subtilis S10 was able to reduce the blood glucose level in STZ-induced diabetic mice.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.1
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• pp.15-21
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• 2003

Quantification of functional components, such as ［l -deoxynojirimycin (DNJ), ${\gamma}$-aminobutyric acid (GABA) and flavonoids］ of four different cultivars (YK-209, Cheongil, Yongchon and Kaeryang) and parts (upper, middle and lower) of mulberry leaves harvested in different areas and periods was performed by HPLC to select the best Quality of mulberry leaf suitable for manufacture of functional foods. Among four mulberry cultivars, YK-209 mulberry leaf had the highest DNJ, GABA and flavonoids levels. YK-209 mulberry leaf harvested in "Yeongcheon" area had greater DNJ, GABA and flavonoid contents than those harvested in "Sangju" area. Four major flavonoids of mulberry leaf were rutin, isoquercitrin, kaempferol-3-Ο-rutinoside, astragalin, and their levels varied greatly with cultivars. YK-BO9 mulberry leaf had the highest flavonoids content among four cultivars. DNJ, GABA and flavonoid contents of young YK-209 mulberry leaf were relatively higher in the upper part than those in the middle and lower parts. Additionally, levels of DNJ, GABA and flavonoids were higher in mulberry leaves harvested in the eariler growing season (May) than in the late growing seasons (June and August) . Particularly, among four flavonoids, rutin content had the highest in the mulberry leaf harvested in May, while isoquercitrin content did the highest in the mulberry leaf harvested in June and August. These results suggest that YK-209 mulberry leaf having high amount of functional components, such as DNJ, GABA and flavonoids, may be useful as potential source of beverages and tablets.verages and tablets.

• Journal of Microbiology and Biotechnology
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• v.23 no.5
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• pp.637-643
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• 2013

We have demonstrated that 1-deoxynojirimycin (DNJ) isolated from Bacillus subtilis MORI could enhance the levels of adiponectin and its receptors in differentiated 3T3-L1 adipocytes, which has been shown to be effective in lowering blood glucose levels and enhancing insulin sensitivity. DNJ was not toxic to differentiated 3T3-L1 adipocytes for up to a concentration of $5{\mu}M$. In terms of expression levels of adiponectin and its receptors (AdipoR1 and AdipoR2), DNJ in concentrations as low as $0.5{\mu}M$ elevated both mRNA and protein levels of adiponectin and transcript levels of AdipoR1 and AdipoR2. In addition, DNJ increased phosphorylation of 5' adenosine monophosphate-activated protein kinase (AMPK) in a statistically significant manner. Finally, treatment with DNJ resulted in increased mRNA expression of glucose transporter 4 (GLUT4), which encodes for a glucose transporter, along with a significant increase in glucose uptake into the adipocytes based on results of a 2-deoxy-D-[$^3H$] glucose uptake assay. Our findings indicate that DNJ may greatly facilitate glucose uptake into adipose tissues by increasing the action of adiponectin via its up-regulated expression as well as its receptor genes. In addition, the glucose-lowering effects of DNJ may be achieved by an increased abundance of GLUT4 protein in the plasma membrane, as a consequence of the increased transcript levels of the GLUT4 gene and the activation of AMPK.

• International Journal of Industrial Entomology and Biomaterials
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• v.34 no.2
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• pp.38-44
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• 2017

Mulberry leaves containing 1-deoxynojirimycin (DNJ) have been recognized as a potentially important source for prevent or treat hyperglycemia. However, DNJ content of natural mulberry leaf are as low as 0.1%. Thus, the most effective method for increasing ${\alpha}$-glucosidase inhibitory activity with the DNJ high-production is needed. In this study, we investigated the influence of ${\alpha}$-glucosidase inhibitory activity according to different pH values (6-9) and inoculation amounts (0.1-0.5%) when Bacillus subtilis cultured on mulberry leaf powder media. We confirmed that ${\alpha}$-glucosidase inhibitory activity was difference according to culture conditions of different pH values, inoculation amounts, and fermentation times. The results of mulberry leaf fermentation according to pH values and inoculation amounts were shown that the optimal conditions for ${\alpha}$-glucosidase inhibitory activity were defined as pH 7 and 9, inoculation amount 0.4%, and incubation until 2 to 4 days. These results can be provided a basic data for the optimal culture conditions increasing ${\alpha}$-glucosidase inhibitory activity from mulberry leaf fermentation.

• Microbiology and Biotechnology Letters
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• v.39 no.1
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• pp.49-55
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• 2011

Thirty Streptomyces sp. and 200 Bacillus sp. isolated from Korean soils and traditional foods were screened for their abilities to inhibit ${\alpha}$-glucosidase and produce 1-deoxynojirimycin (DNJ). This screening identified a Bacillus sp. bacterium that strongly inhibited ${\alpha}$-glucosidase and produced high levels of DNJ from Chungkookjang, a Korean traditional food. The bacterium was characterized in terms of its biochemical and molecular biological properties such as sugar utilization, cellular quinone composition, cell wall fatty acid composition, and 16S rDNA sequence. In addition, scanning electron microscopy was used to visualize the morphology of the bacterium. These analyses identified the bacterium as B. subtilis, a bacterium with Generally Recognized as Safe (GRAS) status. The selected strain was named B. subtilis MORI.

• International Journal of Industrial Entomology and Biomaterials
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• v.27 no.2
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• pp.277-281
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• 2013

Silkworm powder, which contains 1-deoxynojirimycin (DNJ), is a promising complementary and alternative medicine (CAM) in Korea. Silkworm powder was produced from Yeonnokjam pupae at d 3 of the 5th instar at the National Academy of Agricultural Science. The powder was derivatized with 9-fluorenylmethyl chloroformate (FMOC-Cl), and the DNJ-FMOC content was measured by HPLC. We investigated the content of 1-DNJ in the silkworm powder and its glucose-lowering effect when it was treated at different temperatures. The content of 1-DNJ was the lowest at $150^{\circ}C$, while it was constant at other temperatures. The silkworm extract powder was orally administered to diabetic mice (20 mg/kg/d) for 4 wk. Water intake did not significantly change when compared with the control group (T0). The blood glucose levels significantly decreased when mice where administered silkworm powder treated at $60^{\circ}C$ (T60) compared to the control group, but no difference was observed between the groups T100 and T150. Moreover, the blood levels of TG significantly decreased compared with the control group. Based on these results, we surmise that the properties of the silkworm extract powder were stable upon heating at $100^{\circ}C$ but not at $150^{\circ}C$.

• Journal of Microbiology and Biotechnology
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• v.7 no.4
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• pp.262-266
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• 1997

To increase the high production of 1-deoxynojirimycin (DNJ) from Streptomyces sp. SID9135, the effect of various carbon sources, nitrogen sources, cationic metal ions, the initial pH of the medium, and agitation speed were investigated. The most effective carbon and nitrogen sources were found to be lactose 2.5% (w/v) and soybean meal 2.0% (w/v), respectively. None of the cationic metal ions examined had any detectable stimulating effect on DNJ production except $Fe^{+2}$ ion. The initial optimum pH for DNJ production ranged from 6-8 and agitation speed was most effective at 400 rpm. In the jar fermentor experiments under optimal culture conditions, the accumulation of DNJ reached about $640{\mu}g$/ml after 5 days of cultivation and the level remained the same for a further two days.

• Proceedings of the Korean Society of Sericultural Science Conference
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• 2003.04a
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• pp.54-54
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• 2003

DNJ concentration in silkworm, Bombyx mori was traced through the life. DNJ absent in egg existed over the concentration of 5 mg gdw-1 from 1st instar to 4th day of 5th instar during larva period. DNJ concentration decreased drastically with body weight about at 7-8th day of 5th instar when silk production became a major process. (omitted)

• Nutrition Research and Practice
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• v.12 no.6
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• pp.469-478
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• 2018

BACKGROUND/OBJECTIVES: Mulberry leaf (ML) has been shown to have an inhibitory effect on ${\alpha}$-glucosidase, and suppresses postprandial hyperglycemia, which may be related to its deoxynojirimycin (DNJ) content. This study was conducted to investigate the hypoglycemic and dyslipidemic effects of rice coated with ML rich in DNJ in a type 2 diabetes mouse model. MATERIALS/METHODS: The mice were divided into four groups (n = 8 each): non-diabetic normal control (NC); diabetic control (DM-C), fed with 10% polished rice powder (DM-R); and fed with 10% polished rice powder coated with DNJ-rich ML (DM-DNJR). RESULTS: Supplementation with DNJR for six weeks decreased levels of fasting blood glucose, plasma insulin, triglyceride, total cholesterol, and blood glycosylated hemoglobin; conversely, levels of glucagon-like peptide-1 and high-density lipoprotein-cholesterol showed an increase in the same treatment. In addition, weights of mesenteric, epididymal, and total adipose tissues decreased with DNJR supplementation, when compared with diabetic control db/db mice, while maltase, lactase, and sucrase activity in the small intestine were inhibited. The anti-diabetic effects were marginally greater in the DM-DNJR group than in the DM-R group. CONCLUSIONS: These results suggest that rice coated with ML rich in DNJ can reduce hyperglycemia and hyperlipidemia in db/db mice, and may prove useful for individuals with diabetes.