• Archives of Pharmacal Research
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• v.19 no.2
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• pp.112-115
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• 1996

Some antioxidant phenolic compounds exhibit prooxidant activity mainly due to their abilities to reduce $Fe^{3+}\; to\; Fe^{2+}.$ Reducing ability and prooxidant activity of maltol, an antioxidant component of Korean red ginseng, were compared with those of pyrogallol. Maltol at 2 mM did not appreciably reduce$ Fe^{3+}\; to\; Fe^{2+}$ and also failed to reduce nitroblue tetrazolium. Stimulation of hydroxyl radical mediated-deoxyribose degradation by pyrogallol was maximal at 60 .mu.M. Maltol stimulated the deoxyribose degradation to a much less extent, and a similar stimulatory effect was observed at a concentration of more than 100-fold higher than that of pyrogallol. The stimulatory effect of maltol reached a plateau over 1 mM, suggesting the removal of hydroxyl radicals by excess maltol. In bleomycin-$Fe^{3+}$-DNA assay, maltol at 2 mM produced a 2.5-fold increase of the iron-bleomycin-dependent DNA degradation over the basal value, whereas pyrogallol at 10 .mu.M accelerated DNA degradation by ca. 10-fold. Furthermore, maltol inhibited $Fe^{2+}$-stimulated DNA degradation by bleomycin. These results strongly suggested that maltol is an antioxidant with little prooxidant activity.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.82.1-82.1
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• 2003

The protective adaptive response to electrophiles and reactive oxygen species is mediated by enhanced expression of phase II detoxifying genes including glutathione S-transferases. ${\alpha}$-Lipoic acid, which exerts prooxidant or antioxidant activities, has been shown to activate the insulin signaling pathway and thus to induce insulin-like actions via PI3-kinase and Akt. Our previous studies have shown that PI3-kinase plays an essential role in Nrf2-or C/EBP${\beta}$-mediated glutathione S-transferase A2 (GSTA2) induction. (omitted)

• Proceedings of the PSK Conference
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• 2000.10a
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• pp.151.1-151.1
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• 2000

• Clinical and Experimental Reproductive Medicine
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• v.45 no.2
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• pp.82-87
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• 2018

Objective: Concerns about the safety of assisted reproductive technology (ART) have been raised, as some studies have shown elevated incidence rates of childhood cancer, asthma, allergies, and other diseases in ART-conceived babies. Findings regarding the health of ART-conceived babies are controversial. The present study was conducted to evaluate the prooxidant-antioxidant balance (PAB) in in vitro fertilization (IVF)-conceived mice in comparison to naturally conceived offspring. Methods: Mice (6-8 weeks) were divided into two groups (IVF-conceived and naturally conceived) matched by sex, age, weight, and litter size. A 1-mL blood sample was taken and the sera were separated. The oxidant-antioxidant balance was evaluated using a fast and reliable PAB assay. The results were expressed as $mean{\pm}standard$ deviation. Results: The mean PAB values (HK units) in the IVF-conceived and naturally conceived groups were $59.70{\pm}22.30$ and $54.70{\pm}18.22$, respectively (p= 0.82). Conclusion: Since free radicals contribute to several pathological conditions and antioxidants play an important protective role against oxidative stress, evaluating the oxidant-antioxidant balance is very important. Although the results of this study showed that the quality of the defense mechanism against free radicals was not significantly different between the IVF-conceived and naturally conceived mice, other parameters of metabolic dysfunction need to be measured.

• Korean Journal of Food Science and Technology
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• v.22 no.3
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• pp.255-260
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• 1990

The effects of different concentrations of tocopherols on the oxidation stability of evening primrose oil (EPO) in the dark $(35{\pm}2^{\circ}C)$ were evaluated by some physicochemical characteristics such as peroxide, conjugated diene value and fatty acid composition. The results of the present study were as follows; Alpha-tocopherol at all concentrations (0.02%, 0.05%, 0.10%) showed a prooxidant effect during autoxidation of EPO. This prooxidant activity of alpha-tocopherol increased as its concentration increased rapidly. Delta-tocopherol showed antioxidant activity as its concentration increases at an early stage of storage. But the activity was fairly poor antioxidant activity and was not greater than antioxidant activity of BHT. However, the antioxidant effect of delta-tocopherol and BHT showed no apparent differences as compared with result of none.

• Proceedings of the PSK Conference
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• 2001.04a
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• pp.100.1-100.1
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• 2001

• The Korean Journal of Food And Nutrition
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• v.6 no.1
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• pp.47-52
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• 1993

In the present study, an attempt was made to investigate the effect of oleic acid on the autoxidation of the commercial rice bran oil. Rice bran oil samples with oleic acid at 0.1, 0.3 and 0.5% level were kept at 45 $\pm$ 0.3$^{\circ}C$ for 40 days. The rate of autoxidation of each samples was estimated regularly on the basis of the changes of peroxide value, acid value, anisidine value and the fatty acid composition. The per oxide, acid and anisidine values of the rice bran oil with the oleic acid increased as compared with that of the rice bran oil without the oleic acid during the autoxidation. The induction period of the rice bran oil without the oleic acid, control was 19.8 days, while those of the rice bran oil with oleic acid at 0.1, 0.3 and 0.5% levels were 18.3 days, 16.8 days, and 15.5 days, respectively. In conclusion, it seemed that oleic acid acted as weak prooxidant when added at 0.1, 0.3 and 0.5% levels to the commercial rice bran oil.

• The Korean Journal of Food And Nutrition
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• v.4 no.2
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• pp.167-174
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• 1991

In the present study, an attempt was made to Investigate the effect of stearic acid on the autoxidation of the commercial rice bran oil, Rice bran oil samples with stearic acid at 0.1, 0.3 and 0.5oh level were kept at 45$\pm$0.3$^{\circ}C$ for 40 days. The rate of autoxidation of each samples was estimated regularly on the basis of the changes of peroxide value, acid value, anisidine value and the fatty acid composition. The results were as follows : The peroxide, acid and anisidine values of the rice bran oil with the stearic acid at 0.1, 0.3 and 0.591 levels during the autoxidation Increased as compared with that of the rice bran oil without the stearic acid. The induction period of the rice bran oil without the stearic acid, control was 19.0days, while those of the bran oil with stearic acid at 0.1, 0.3 and 0.5% levels varied 19.0 days, 17.7days and 14.2 days, respectively. In conclusion, it seemed that stearic acid acted as weak prooxidant when added at 0.1, 0.3 and 0.5% levels to the commercial rice bran oil. The prooxidant activity of the stearic acid appeared to depend on the oxidative mechanism and their concentration.

• Journal of Life Science
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• v.20 no.11
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• pp.1611-1616
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• 2010

The purpose of this research was to determine the effect of surfactant micelles on lipid oxidation in W/O/W multiple emulsions. The content of ferric irons and hydroperoxide in the continuous phase in W/O/W multiple emulsions was measured as a function of Brij micelle. The concentration of ferric iron and hydroperoxide in the continuous phase increased with increased storage time (1~6 days). Lipid oxidation rates, as determined by the formation of lipid hydroperoxides, TBARs and headspace hexanal, in the W/O/W multiple emulsions containing ferric iron decreased when 3% surfactant micelles were exceeded. These results indicate that excess surfactant micelles could alter the physical location and prooxidant activity of iron in W/O/W multiple emulsions.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.1
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• pp.60-66
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• 1995

The oxidation of purified pinenut oil containing various concentration of tocopherols and β-carotene were studied. α-tocopherol revealed an antioxidant activity at the concentration of lower than 0.05%, however, it showed a prooxidant activity when the concentration was higher than 0.05%. The antioxidant activity of γ-tocopherol was not affected by the concentraitons in the range of 0.01∼0.10% in pinenut oil. γ -Tocopherol resulted in higher antioxidant activity than that of α-tocopherol. β -carotene seemed to be a prooxidant when 0.01% of β-carotene was added. The fatty acids composition of purified pinenut oil have been changed during autoxidation. The concentration of linoleic acid decreased readly while oleic acid seemed to increase. And the concentration of saturated fatty acid has'nt been changed much during autoxidation.