• Journal of Community Nutrition
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• v.8 no.4
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• pp.207-213
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• 2006

The present study was conducted to investigate the effect of oolong tea extract on blood glucose level and antioxidant system in diabetic rats. The Sprague-Dawley rats were fed on AIN-76 based experimental diets containing 1 % oolong tea extract for 6 weeks. They were induced to be diabetic by receiving streptozotocin (45mg/kg BW) intramuscularly. Blood glucose, blood and hepatic concentration of vitamins A and E, and antioxidant enzyme activities were measured. Oolong tea extract feeding decreased the plasma glucose in diabetic rats. Dietary supplementation of oolong tea extract did not affect antioxidative enzyme activities such as superoxide dismutase, glutathione peroxidase and catalase in diabetic rats. The plasma level of retinol was increased in diabetic rats by feeding oolong tea extract. Plasma and hepatic levels of ${\alpha}$-tocopherol were higher in diabetic rats fed oolong tea extract. In conclusion, these results suggest that oolong tea extract consumption might reduce the plasma glucose in diabetic rats and protect the oxidative damage from diabetic stress to some extent.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.187-187
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• 1998

The objective was to verify biological activities of fruit and stem of prickly pear(Opuntia ficus indica L. var, saboten Makino). We have determined inhibitory activities on enzymes, such as dopamine ${\beta}$-hydroxylase(DBH), monoamme oxidase A and B(MAO-A, B), and antioxidant activity, in vitro. We purchased dried stem powder and lyophilized fruit powder of prickly pear from CheJu Island, and prepared the extracts with 80% of methanol. The fruit extract showed stronger inhibitory effects on MAO-A and -B and antioxidant activity compared. to the stem extract, on fractionation with hexane, ethyl acetate, butanol and water. Both the stem and the fruit extracts with ethyl acetate showed stronger enzyme inhibitory and antioxidant activities than other extracts. Now we are isolating active principles from both ethyl acetate extracts.

• Mycobiology
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• v.39 no.2
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• pp.137-139
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• 2011

A Vitis hybrid-Vitis coignetiae red wine was vinified by fermentation of a mixture of a Vitis hybrid.Vitis coignetiae must with Saccharomyces cerevisiae KCTC 7904 at $25^{\circ}C$ for 10 days. The Vitis hybrid-Vitis coignetiae red wine showed high antihypertensive angiotensin I-converting enzyme (ACE) inhibitory activity (67.8%) and antioxidant activity (76.7%). The antihypertensive ACE inhibitor in the Vitis hybrid-Vitis coignetiae red wine was partially purified by solid phase extraction chromatography, and its ACE inhibitory activity yielded an $IC_{50}$ of 1.8 mg/mL. Six kinds of oligopeptides, including five new kinds, were contained in the partially purified ACE inhibitor fraction from the red wine after 10 days of fermentation. Antioxidant activity decreased significantly from 76.7% to 40.5% when the post-fermentation period was prolonged to 30 days.

• Korean Journal of Plant Resources
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• v.26 no.1
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• pp.60-67
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• 2013

A laboratory experiment was conducted to determine the content of phenolics and flavonoids, antioxidant activity and antioxidant enzyme activity for the extracts from cowpea seed and sprouts. Plant length and weight of cowpea sprouts were significantly increased until 7 days after seeding. Total phenolics level [mg chlorogenic acid equivalents (CAE) $kg^{-1}$ DW] was highest in dry seed (DS) extracts of cowpea ($63.9mg\;kg^{-1}$), followed by imbibed seed (IS) ($56.8mg\;kg^{-1}$) and 1-day-old sprout (1DOS) extracts ($46.4mg\;kg^{-1}$), and significantly reduced with increase of sprout age (p < 0.05). The antioxidant activity of the methanol extracts from all the samples showed same tendency to the results of total phenolics level, and dose-dependently increased. DPPH (1,1-diphenyl-2-picryl hydrazyl radical) free radical scavenging activity was higher in DS (87.3%) and IS (41.2%) than in cowpea sprouts from 1DOS to 7DOS, ranging from 17.1 to 30.4%. Antioxidant enzymes, APX, POX, and POX activities were highest in 7DOS and lowest in DS. SOD activity showed much higher activity in sprouts and in seeds. Correlation coefficient between physiological-active substance and the activity was highest between APX and CAT activities ($r^2$= 0.9574). Especially, total phenolics content was more highly correlated with antioxidant or with antioxidant enzyme activities than was total flavonoid level.

• Proceedings of the Botanical Society of Korea Conference
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• 2002.04a
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• pp.101-101
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• 2002

• Nutrition Research and Practice
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• v.5 no.5
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• pp.429-434
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• 2011

Korean raspberry, Rubus coreanus Miquel (RCM), contains high concentrations of phenolic compounds, which prevent oxidative stress. To determine the effect of RCM on antioxidant capacity in humans, we assessed in vivo lipid oxidation and antioxidant enzyme activities from plasma in 15 healthy men. The subjects ingested 30 g of freeze-dried RCM daily for 4 weeks. Blood was taken at baseline and at the end of the study to determine blood lipid profiles, fasting plasma glucose, liver function, lipid peroxidation, and antioxidant enzyme activities. RCM supplementation had no effect on blood lipid or fasting plasma glucose concentrations but decreased alkaline phosphatase activity. RCM supplementation increased glutathione peroxidase activities (P<0.05) but had no effect on lipid peroxidation. These results suggest that short-term RCM supplementation may offer health benefits by enhancing antioxidant capacity in a healthy population.

• Journal of Environmental Science International
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• v.16 no.12
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• pp.1345-1353
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• 2007

The effect of salicylic acid(SA) on antioxidant system and protective mechanisms against UV-B induced oxidative stress was investigated in cucumber(Cucumis sativus L.) leaves. UV-B radiation and SA were applied separately or in combination to first leaves of cucumber seedlings, and dry matter accumulation, lipid peroxidation and activities of antioxidant enzymes were measured in both dose and time-dependant manner. UV-B exposure showed reduced levels of fresh weight and dry matter production, whereas SA treatment significantly increased them. SA noticeably recovered the UV-B induced inhibition of biomass production. UV-B stress also affected lipid peroxidation and antioxidant enzyme defense system. Malondialdehyde(MDA), a product of lipid peroxidation, was greatly increased under UV-B stress, showing a significant enhancement of a secondary metabolites, which may have antioxidative properties in cucumber leaves exposed to UV-B radiation. Combined application of UV-B and SA caused a moderate increase in lipid peroxidation. These results suggest that SA may mediate protection against oxidative stress. UV-B exposure significantly increased SOD, APX, and GR activity compared with untreated control plants. Those plants treated with 1.0 mM SA showed a similar pattern of changes in activities of antioxidant enzymes. SA-mediated induction of antioxidant enzyme activity may involve a protective accumulation of $H_2O_2$ against UV-B stress. Moreover, their activities were stimulated with a greater increase by UV-B+SA treatment. The UV-B+SA plants always presented higher values than UV-B and SA plants, considering the adverse effects of UV-B on the antioxidant cell system. ABA and JA, second messengers in signaling in response to stresses, showed similar mode of action in UV-B stress, supporting that they may be important in acquired stress tolerance. Based on these results, it can be suggested that SA may participates in the induction of protective mechanisms involved in tolerance to UV-B induced oxidative stress.

• Korean Journal of Community Nutrition
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• v.7 no.6
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• pp.844-851
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• 2002

Smoking can increase oxidative stress and thereby change the antioxidant defense system in the body. To investigate the relationship between male adolescent smoking and antioxidant status, we surveyed the eating habits and dietary intake of 82 smokers and 44 nonsmokers recruited from a male technical high school. In addition, antioxidant enzyme activity and lipid peroxide values were determined in both the plasma and the erythrocytes. Although the frequency of food intake was not significantly different, most nutrient intake was unexpectedly higher in smokers than in nonsmokers. In comparison with the Korean RDA, especially the average intake of Ca, Fe and vitamin $B_2$ didn t reach 75% of the Korean RDA in either smokers or nonsmokers. An analysis of antioxidant enzyme activity showed that plasma catalase. superoxide dismutase (SOD), glutathione peroxidase (GSH-px), erythrocyte catalase and GSH-px activities showed no significant difference between smokers and nonsmokers. However, the erythrocyte SOD activity of smokers (1.57 unit/mgHb) was significantly lower than that of nonsmokers (2.00 unit/mg Hb). In addition, the plasma ceruloplasmin concentration of smokers (28.68 mg/$d\ell$) was significantly higher than that of nonsmokers (26.30 mg/$d\ell$), whereas the specific ceruloplasmin ferroxidase activity of smokers (0.31 unit/mg) was lower than that of nonsmokers (0.35 unit/mg). The plasma and erythrocyte thlobarbituric acid reactive substance (TBARS) of smokers (2.57 $\mu$mol/L, 0.32 $\mu$mol/gHb) were also significantly higher than those of nonsmokers (2.25 $\mu$mol/L, 0.27 $\mu$mol/gHb). The overall data indicate that adolescent smoking might decrease the antioxidant capacity of the body, in part, by lowering the erythrocyte SOD activity and the specific ceruloplasmin ferroxidase activity.

• Preventive Nutrition and Food Science
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• v.11 no.4
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• pp.289-297
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• 2006

This study examined the effect of hesperidin supplementation with an ethanol diet on lipid and antioxidant metabolism in rats. Male Sprague-Dawley rats were divided into two groups (n=10), and were assigned to one of two dietary categories: $E_8$, ethanol diet (50 g/L) for 8 wks; $E_8H_4$, ethanol diet for the first 4 wks and hesperidin (0.02%, w/w) supplemented ethanol diet for the last 4 wks. The plasma and hepatic lipids, hepatic cholesterol regulating enzyme activity, hepatic antioxidant enzyme activity and lipid peroxidation were determined. Supplementation with hesperidin for the last 4 wks during the 8 wks period of the ethanol diet, significantly increased the ADH activity. In conjunction with the chronic administration of ethanol, hesperidin supplementation resulted in a significant decrease in the hepatic cholesterol and triglyceride concentrations compared to the $E_8$ group. The hepatic HMG-CoA reductase and ACAT activities were significantly lower in the hesperidin-supplemented group. When comparing hepatic antioxidant enzyme activities, SOD, GSH-Px, and G6PD activities and GSH level were significantly higher in the $E_8H_4$ group than in the E8 group. Plasma TBARS levels were significantly lower in rats fed ethanol with hesperidin compared to the rats fed only ethanol; however, the hepatic TBARS levels were not significantly different between the groups. Accordingly, the additional hesperidin supplement with an ethanol diet might be effective for improving the hepatic lipid metabolism and antioxidant defense system.

• Nutritional Sciences
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• v.7 no.1
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• pp.35-40
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• 2004

This study was performed to evaluate the effect of iron supplementation on iron-deficiency-related indices, oxidative stress and antioxidative enzyme activity in female marathoners. Fourteen teenage female marathoners participated in the study. Subjects were divided into two groups: mild anemic and control, depending on their hemoglobin (Hb) level. The mild anemic group had significantly lower RBC count and hematocrit (Hct) and Hb levels compared to the control group. The mild anemic group (〈12.5g Hb/dI, n=7) was given iron supplements (60mg Fe/day) for four weeks during the summer training period. RBC count, Hct and Hb levels showed an increasing tendency through iron supplementation, and significant differences in these variables between the anemic and control groups disappeared in the post-period. There was no difference in plasma malondialdehyde (MDA) between the anemic and control groups. However, catalase (CAT) and glutathione peroxidase (GPx) activity were significantly higher in the anemic group. The significant difference in enzyme activity between the groups disappeared in the post-period. In addition, superoxide dismutase activity significantly decreased after iron supplementation. In conclusion, antioxidative enzyme activity was up-regulated in an anemic condition and mild iron supplementation decreased the antioxidant enzyme activity of female marathoners while improving their anemic condition.