• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.6
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• pp.1071-1077
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• 2002

The purpose of this study was investigated the effects of YK-209 mulberry leaves on disaccharidase activites of small intestine and blood glucose-lowering in diabetic rats induced with streptozotocin (STZ). Male Sprague-Dawley rats weighing 100$\pm$10 g were randomly assigned to one normal and four STZ-induced diabetic groups; YK-209 0% mulberry leaves diet (DM group),0.1% YK-209 mulberry loaves diet (DM-0.1Y group),0.2% YK-209mulberry leaves diet (DM -0.2Y group), and 0.4% YK-209 mulberry leaves diet (DM -0.4Y group). Diabetes was induced by intravenous injection of 55 mg/kg body weight of STZ in sodium citrate buffer (pH 4.3) via tail vein after 3 weeks feeding of experimental diets. Rats were sacrificed at the 9th day of diabetic states. The functional ingredients in the mulberry leaves, the 1-deoxynojirimycin (DNJ) contents of YK-209 mulberry leaves was higher than those of the Cheongil mulberry leaves. ${\gamma}$ -Aminobutyric acid (GABA) and rutin contents of YK-209 mulberry leaves were 1.3 and 1.4 times higher than those of the Cheongil mulberry leaves, respectively, and vitamin C contents of YK-209 mulberry leaves were also higher than those of the Cheongil mulberry leaves. Intestine index was increased in all diabetic groups, compared with normal group but not significantly different among all diadetic groups. Level of blood glucose was decreased in diadetic rats by supplementation YK-209 mulberry leaves. The disaccharidase activities in proximal part of intestine such as maltase, sucrase, and lactase in YK-209 mulberry leaves supplementation groups were significantly lower than those of DM group, In conclusion, this research indicated that the functional ingredients of YK 209 mulberry leaves were higher than those of the Cheongil leaveses, and YK-209 mulberry leaves has the hypoglycemic effect in STZ-induced diabetic rats.

• 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 the Korean Society of Food Science and Nutrition
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• v.31 no.5
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• pp.826-833
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• 2002

This study was conducted to investigate the effects of YK-209 mulberry leaves on HMG-CoA reductase activity and lipid composition of liver in streptozotocin-induced diabetic rats. Sprague-Dawley male rats weighing 100 $\pm$ 10 B were randomly assigned as a normal group and four STZ-induced diabetic groups according to the level of dietary mulberry leaves supplement. The experimental diets were fed ad libidum, so that diabetes was experimentally induced by intravenous injection of STZ 55 mg/kg of body weight after feeding for 3 weeks. Animals were sacrificed on the 9th day of diabetic states. The levels of serum triglyceride, total-cholesterol and LDL-cholesterol in DM group were higher than mulberry leaves supplemented groups and normal group, but those of the mulberry leaves supplemented groups were significantly decreased to normal level. In contrast, the leavels of serum HDL-cholesterol in DM group was significantly reduced than that of normal group, but mulberry leaves supplemented groups were increased to normal level. Atherogenic index in DM group was higher about 3 fold than the normal group but the DM-0.1Y and DM-0.2Y groups were maintained the normal level. Contents of total lipid and triglyceride of liver in DM group were significantly lower than that of normal group, but the mulberry Leaves supplemented groups increased than that of DM group. The contents of hepatic cholesterol in DM group was 160% higher than that of normal group, but the mulberry leaves supplementation groups maintained the normal level. The activity of hepatic 3-hydroxy -3-methylglutaryl Coenzyme A (HMG-CoA) reductase in DM group was 43% lower than that of normal group, but had no significant difference between DM-0.1Y, DM-0.2Y and normal groups. In conclusion, YK-209 mulberry loaves has improving effect of the lipid metabolism in STZ-induced diabetic rats through hepatic HMG-CoA reductase activity, and the change of lipids contents in serum and liver.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.6
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• pp.1065-1070
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• 2002

The purpose of this study was investigated the effects of YK-209 mulberry leaves on antioxidative defense system of liver in diabetic rats induced with streptozotocin (STZ). Male Sprague-Dawley rats weighing 100$\pm$10 g were randomly assigned to one normal and four STZ-induced diabetic groups; YK-209 mulberry leaves free diet (DM group),0.1% YK-209 mulberry leaves diet (DM-0.1Y group),0.2% YK-209 mulberry leaves diet (DM-0.2Y group) and 0.4% YK-209 mulberry leaves diet (DM-0.4Y group). Diabetes was induced by intravenous Injection of 55 mg/kg body weight of STZ in sodium citrate buffer (pH 4.3) via tail vein after 4 weeks feeding of experimental diets. Rats were sacrificed at the 9th day of diabetic states. Liver weight in all four diabetic groups were higher than normal group, but YK-209 mulberry supplementation groups were lower than DM group. Hepatic superoxide dismutase (SOD) activity was significantly decreased in all diabetic groups, compared with normal group. Hepatic glutathione peroxidase (GSHpx) activity was 7.3% decreased in DM group, compared with normal group, but those of DM-0.1Y and DM-0.2Y groups were maintained the normal level. The hepatic thiobarbituric acid reactive substances was markedly increased by 144% in DM group, compared with normal group, but those of DM-0. 1Y, DM-0.2Y groups were maintained the normal level. The contents of lipofuscin in liver were increased by 100% in DM group compared with normal group, but those of DM-0. 1Y, DM-0.2Y and DM-0.4Y groups were decreased to 42% 43% and 44%, respectively, compared with DM group. The hepatic superoxide radical (0$^2$-) contents in DM group were increased to 81%, compared with normal group, but those of DM-0.1Y and DM-0.4Y groups were similar to those of normal group. The present result indicate that YK-209 mulberry leaves regarded to suppress lipid peroxidation as an free radical scavenger system by the inhibition of oxidative stress.

• International Journal of Industrial Entomology and Biomaterials
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• v.2 no.1
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• pp.27-35
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• 2001

This study was carried out to investigate the mineral content in the regional, varietal and seasonal mulberry leaves. On average, mulberry leaf samples contained minerals in the order of potassiumi phosphorus, calcium, magnesium, iron and so on (2.494 g/100 g, 2.255 g/100 g, 1.835 g/100 g, 0.627 g/100 g, 0.0245 g/100 g DW, respectively). Calcium content was 19-fold and 4-fold higher than that of green tea and spinach, respectively, suggesting that mulberry loaves appear to be a calcium-rich food source. In the comparison of geographic samples of Cheongilppong variety, calcium bevel was highest in Youngchun sample (2.477 g/100 g) and highest potassium level in Suwon sample (2.962 g/100 g). In the geographic samples of YK209 variety, Jinju-City sample was highest in calcium content (1.509 g/100 g). Among wild mulberry loaves collected from Cheju Island and Tsushima, potassium level was highest in Bongge-dong, Cheiu City (3.865 g/100 g) and calcium level in Mitshshima Town, Tsushima (2.948 g/100 g). In the comparison of varietal samples collected in Suwon at the mulberry field of Dept. of Sericulture & entomology, Shinkwangppong variety was highest in the potassium levels although Keryangppong and Shinkwangppong were higher in calcium revel. In the comparison of seasonal samples of Cheongilppong, there was a rough trend of increase in some minerals up to July (e.g., calcium rind )potassium). Finding of the highest calcium and potassium contents in the wild mulberry (3.865 g/100 g and 2.948 g/100 g, respectively) rather than in the cultivated ones warrant that more focus should be paid to wild mulberry leaves to utilize their minerals effciently.

• International Journal of Industrial Entomology and Biomaterials
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• v.2 no.2
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• pp.141-147
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• 2001

This study was carried out to find out whether there exists any content variation in 1-deoxynojirimycin (DNJ) among regional and varietal mulberry leaves. HPLC analysis was performed for 22 samples collected from several localities in Korea and Tsushima Islands Japan. The highest content was observed in the Cheongilppong sample collected at Youngchun City, Kyungsangbuk Province (1,882.7 $\mu\textrm{g}$/g DW), whereas lowest content was observed in the Cheongilppong sample collected at Jiniu City, Kyungsangnam Province (395.65 $\mu\textrm{g}$/g DW). In the comparison of regional samples of Kaeryangppong variety, DNJ content was highest in the order of Woniu City (1,460.1) > Boungun (999.85) > Hweongsung-gun (939.12) > Cheongju City (688.78). In case of Cheongilppong, DNJ content was highest in the order of Youngchun City (1.882.8) > Sanchung-gun (1,125.3) > Sunchon City (649.17) > Byunsan-myon (441.54) > Jinju City (395.65). Average content of regional samples was higher in Kaeryangppong (1,021.7 $\mu\textrm{g}$/g DW) than that of Cheongilppong (898.87 $\mu\textrm{g}$/g DW). Average DNJ content of the wild mulberry loaves collected from Cheju Island and Tsushima Island (1,012.9$\mu\textrm{g}$/g DW) was high enough to reach to that of the regional Kaeryangppong samples. In the comparison among varietal samples collected in Suwon, the highest DNJ content was observed in YK209 (768.16 $\mu\textrm{g}$/g DW), amongst overall low DNJ content of the varietal samples. Considering a few pieces of information from our data, DNJ content appears not to be influenced solely by annual temperature of the planted areas.