• Asian-Australasian Journal of Animal Sciences
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• v.22 no.11
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• pp.1587-1593
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• 2009

Duck egg white (DEW) hydrolysates were prepared by five enzymes (papain, trypsin, chymotrypsin, alcalase, and flavourzyme) and their antioxidant activities investigated in this study. DEW hydrolyzed with papain (DEWHP) had the highest peptide content among the five enzymatic treatments. Besides, the peptide content of DEWHP increased when the enzyme to substrate ratio (E/S ratio) increased. It was suggested that higher E/S ratio contributed to elevate the degree of hydrolysis of DEW effectively. Similar results were also obtained by Tricine-SDS-PAGE. In addition, SDS-PAGE patterns indicated papain was the only one amongst all enzymes with the ability to hydrolyze DEW. In antioxidant properties, DEWHP showed more than 70% of inhibitory activity on linoleic acid peroxidation and superoxide anion scavenging. Moreover, the $Fe^{2+}$ chelating effect of DEWHP was greater than 90%, while no significant difference was observed in DPPH radical scavenging and reducing ability. The results of peptide contents, antioxidant activities and electrophoresis suggested that the higher the peptide content, the stronger the antioxidant activities in DEWHP.

• Journal of Nutrition and Health
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• v.53 no.3
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• pp.244-254
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• 2020

Purpose: Ixeris strigosa (IS) is a perennial plant that commonly grows in meadows. The leaves and roots of IS have been used in medicine as a sedative. This study evaluated the antioxidant and carbohydrate-digestive-enzyme inhibitory effects of IS to determine its potential as an essential antioxidant and glycemic inhibitor for type 2 diabetics. Methods: The antioxidative and α-amylase and α-glucosidase inhibitory activities were examined using the water extracts (ISW), ethanol extracts (ISE), and solvent fractions from IS. The antioxidative activities were measured using in vitro methods by measuring the 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid radical scavenging activity. Results: Investigations of the total polyphenol, flavonoid content, in vitro antioxidant activity, and α-amylase and α-glucosidase inhibitory activities of the IS extract showed that the ISE had higher total phenolic and flavonoid contents than the ISW, as well as high antioxidant activity. The ethanolic extracts of IS (70%) had an α-amylase inhibitory activity of 78.55%. The ethyl acetate fraction (90.56%) showed higher α-glucosidase inhibitory activity than the positive control, acarbose (83.01%). Conclusion: Among the ISE fractions, the ethyl acetate and butanol fractions showed the best digestive enzyme inhibitory activity. Moreover, the antioxidant activity of the extract and the carbohydrate, α-amylase, and α-glucosidase inhibitory effects showed a stronger correlation with the total phenol and flavonoid contents compared to the ISW. As a result, the antioxidant and digestive enzyme inhibitory activities of high ISE are due to the phenolic compounds, particularly the flavonoid compounds. Therefore, ethyl acetate and butanol fractions of the 70% ethanol extract are excellent anti-diabetic functional materials.

• Preventive Nutrition and Food Science
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• v.10 no.3
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• pp.244-250
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• 2005

The copper-containing enzyme, tyrosinase, catalyzes the oxidation of tyrosine into dihydroxy phenylalanine (DOPA) and subsequently DOPAquinone. It is responsible, not only for the pigment melanin biosynthesis in human skin, but also for browning in foods. In the present study, tyrosinase inhibitory and antioxidant activities of Korean mistletoe extract and its fractions were investigated. As a result, both water and methanol (MeOn) extracts inhibited the tyrosinase activity. Among the fractions, the fraction eluted with $95\%$ MeOn significantly inhibited the tyrosinase activity. The fraction was further purified, and the purified fraction C strongly inhibited the enzyme activity up to $92\%$. In addition, water and methanol extracts exerted radical scavenging effects. The fractions eluted with $70\%\;MeOn\;and\;95\%$ Me on showed high radical scavenging activities. In conclusion, these results suggest that Korean mistletoe extract and its fractions might be useful for the treatment of various dermatological disorders such as epidermal hyperpigmentation and for improving food quality.

• Biomolecules & Therapeutics
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• v.9 no.4
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• pp.249-257
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• 2001

The effect of oxidative stress on the alterations of different antioxidant enzyme activities was investigated in human skin melanoma cell line (SK-MEL-2). Oxidative stress was induced by the exposure to hydrogen peroxide ($H_2O$$_2$). SK-MEL-2 cells were treated with antioxidants such as vitamin E and selenomethionine in combination with $H_2O$$_2$. SK-MEL-$_2$ cells were exposed to various concentrations of $H_2O$$_2$ and measured the time course of changes in cell viability and antioxidant enzyme activities for 24 hr. Oxidative stress was induced by the exposure to 2.5mM hydrogen peroxide ($H_2O$$_2$) resulted in declining significantly for 24 hr. GPX and CAT activities peaked at 3 hr and returned to control levels by 24 hr. On the contrary, SOD activity was inactive before 6 hr but recovered at 24 hr. In case vitamin E (Vit E) and selenomethionine (Se-Met) were used at nontoxic concentrations (25$\mu$M Vit E/500$\mu$M Se-Met) to oxidative stress was induced by the exposure to hydrogen peroxide ($H_2O$$_2$) led to a 3- and 5-fold increase on the viability comparing to control and caused an increase in GPX activity respectively.

• Journal of Nutrition and Health
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• v.35 no.4
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• pp.431-438
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• 2002

This study was performed to investigate the effects of green tea or antioxidant vitamins on lipid peroxidation and antioxidant enzyme system in various regions of rat brain aged 9 and 12 months. Male Sprague-Dawley rats were raised on the experimental diets; 3% green tea powder diet, antioxidant vitamins diet containing the $\beta$-carotene, vitamin C, vitamin E in the level same as in the 3% green tea powder diet, and control diet far 3 weeks. We measured concentrations of malondialdehyde (MDA) and the activities of superoxide dismutase (SOD), catalase, and glutathione peroxide (GSH-Px) in various brain regions such as cortex, cerebellum, striatum, and hippocampus. Green tea powder or antioxidant vitamin supplementation decreased MDA concentrations in the striatum and the hippocampus, and increased SOB activities in the striatum, and GSH-Px activities in the cortex. There was no significant difference in the observed antioxidative effects between the green tea powder and antioxidant vitamin supplementation. A significant difference between 9 month- and 12 month-old rats was found in MDA concentrations and GSH-Px activities in all brain regions. These results suggest that green tea powder can have protective effects on various regions of rat brain and that these effects on lipid peroxidation and antioxidant enzymes are different by age. In inhibiting lipid peroxidation, there was no difference between green tea powder and antioxidant vitamins.

• Food Science of Animal Resources
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• v.36 no.1
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• pp.44-50
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• 2016

This study was conducted to observe the association between antioxidant enzyme activity, free iron content and lipid oxidation of Korean native chicken (KNC) meat during refrigerated storage. Four lines of KNC (Yeonsan ogye, Hyunin black, Hoengseong yakdak and Hwangbong) were raised under similar conditions. A total of 16 roosters were randomly sampled and slaughtered at the age of 12 mon. The breast and thigh meats were stored aerobically for 10 d at 4℃. Although thigh meat had higher antioxidant enzyme activity, it was more susceptible to lipid oxidation and released more iron during storage than breast meat. Aerobic refrigerated storage for 10 d significantly decreased the activity of antioxidant enzymes and increased the amount of free iron and malondialdehyde. The activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were negatively correlated with lipid oxidation, whereas that of catalase was not. The amount of free iron was positively associated with lipid oxidation. We concluded that chicken line did not affect strongly on antioxidant enzyme activity and lipid oxidation in breast meat of KNC. However, the thigh meat of Hwangbong and Hyunin black had higher SOD and GSH-Px activity, respectively, and lower malondialdehyde contents than that of other chickens. SOD, GSH-Px and free iron play significant roles in meat lipid oxidation during refrigerated storage.

• Journal of Ginseng Research
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• v.18 no.1
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• pp.25-31
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• 1994

The effects of red ginseng extracts (5.5 mg/mouse: i.p.) on the activities of antioxidant enzymes (superoxide dismutase, catalase and peroxidase) and lipid peroxidation were studied in the cytosol fraction of kidney. The experiments were carried out with whole-body irradiated (6.0 Gy, $^{60}Co$) and non-irradiated ICR mice. In the red ginseng extract-treated and irradiated mice, the activities of Cu, Zn- SOD, Mn-SOD, catalase and peroxidase were significantly enhanced by 27.8, 31.9, 17.9 and 15.0%, respectively, but the contents of malondialdehyde were considerably decreased (81.OfS) after 21 days, compared with those of non-treated mice. The enhanced activities of antioxidant enzymes inhibited the increase of malondialdehyde product resulted from the ionizing radiation. These results suggest that red ginseng extracts probably play an important role in radioprotective effect. Key words Red ginseng, SOD, catalase, peroxidase, lipid peroxidation.

• Korean Journal of Environmental Biology
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• v.18 no.2
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• pp.247-253
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• 2000

In order to investigate the stimulatory effect(hormesis) of low dose gamma-radiation on the seeding growth of old seeds with respect to antioxidant defense systems, various doses of gamma radiation to the 5-year-old dried seeds of Chinese cabbage (Brassica campestris L. cv Sulin eockaei). Compared to the new, 1-year- old seeds, old seeds irradiated by low does gamma radiation in the range of 1-2 Gy showed vigor growth as revealed by statistically significant increases both in the germination rates and the leaf size and fresh weight. Further, seedlings grown from seeds treated by low dose gamma radiation showed higher peroxidase and catalase activities than non-treated seedlings. These results suggest that the antioxidant defense systems could be closely related to the stimulatory effects of low dose radiation. [antioxidant enzyme, chinese cabbage, gamma radiation, germination rate, hormesis]

• Korean Journal of Plant Resources
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• v.24 no.1
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• pp.105-112
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• 2011

The objective of this study was to determine the effect of antioxidant enzyme activity and radical scavenging activities of thirteen kinds of natural plant pigments. The analytic method of antioxidant activities were measured by estimating DPPH free radical scavenging and nitrite scavenging ability activity. The free radical scavenging activity by method using stable free radical DPPH was the highest in the red cabbaged pigment. Addition of ethanol extract 1mg/ml from onion peel pigment displayed remarkable effect on nitrite scavenging ability about 91.9%. Antioxidative enzyme activity was evaluated in terms of superoxide dismutase(SOD), catalase(CAT), and ascorbate peroxidase(APX) activity. The bitter melon pigment had the highest SOD activity of 87.3%. The activities of CAT and APX were higher in the mulberry leave pigment compared with other natural plant pigments. In contrast, CAT activity of plant pigment samples were unaffected. These results suggest that natural plant pigment had the potent biological activities such as antioxidant enzyme activities, and that their activities exhibited differently depending on each kind of pigments.

• Preventive Nutrition and Food Science
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• v.6 no.1
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• pp.51-56
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• 2001

This study was carried out to evaluate whether antioxidant nutrient suppplementation with $\alpha$-tocopherol, vitamin C, $\beta$-carotene, and selenium reduces the lipid peroxide levels and increases the antioxidative enzyme activities in patients with coronary hart disease. Eighty nine patients participated in a randomized, double-blind, placebo-controlled trial. The antioxidant group (45 patients) was given daily doses of $\alpha$-tocopherol (400 IU), vitamin C (50 mg), $\beta$-carotene (15 mg), and selenium (50 $\mu\textrm{g}$) and forty four patients received a placebo. Thirty eight subjects (84.4%) of the antioxidant group and thirty nine subjects (88.6%) of the placebo group completed the three-month supplementation. Serum levels of tocopherol, vitamin C and $\beta$-carotene significantly increased in the antioxidant group compared with the baseline (p<0.05). Thiobarbituric acid-reactive substances(TBARS) decreased significantly (0.6 nmol MDA/mL) in the antioxidant group compared with that (0.09 nmol MDA/mL) in the placebo group (p=0.03). However, antioxidant supplementation did not affect the level of oxidized-LDL measured as autoantibodies against oxidized-LDL. The superoxide dimutase activity in red blood cells increased in the antioxidant group compared with the baseline (p<0.05). However, glutathione peroxidase activities did not change after supplementation in both groups, and catalase activity significantly decreased in the placebo group (p<0.05). These results suggest that antioxidant supplementation for 3 months with $\alpha$-tocopherol, vitamin C, $\beta$-carotene and selenium in patients with coronary heat disease may be partially protective against oxidative stress.