• Journal of Nutrition and Health
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• 제25권2호
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• pp.116-122
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• 1992

This study determined hepatic microsomal lipid peroxide values glucose 6-phosphatase NA-DPH-cytochrome P450 reductase and cytosolic glutathione S-transferase activites to examine the effects of methyl group deficiency on hepatic lipid peroxidation in rats treated with diethylni-trosamine(DEN) and 2-acetylamionfluorene(AAF) Weanling sprague Dawley male rats were fed the diet with methyl group supplemented or deficient. Two weeks after feeding rate were injected with a single of 200mg/kg body weight DEN intraperitoneally and after four weeks 0.02% AAF containing diets were fed for two weeks. Animals were sacrificed at 6th week. Microsomal lipid peroxide values were tended to increase in methyl group deficiency(MD). Especially in case of carcinogen tratments lipid peroxide values were increased significantly in MD. Microsomal glucose 6-phophatase activities were decreased by MD and carcinogens and in MD with carcinogen group (MD+C) the enzyme activites were the lowest Glucose 6-phosphatase activities were negatively correlated with lipid peroxidation. Microsomal NADPH-cytochrome P450 reductase activities were the highest in MD+C and correlated positively with lipid peroxidation. Cytosolic glutathione S-transferase activities were the highest in MD+C Methyl group deficiency induces lipid peroxidation especially in case of being exposed to carcinogens. Therefore the results suggest that lipid peroxidation may be one of the meachanisms of carcinogensis by methyl group deficiency.

• 대한수의학회지
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• 제43권4호
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• pp.579-585
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• 2003

The studies were carried out on the correlation between microsomal lipid peroxidation level and drug metabolizing enzyme activities in rat liver microsomal suspensions on various ages (2-week-old, 2, 4, 8, and 12-month-old). The lipid peroxidation levels of liver homogenates tended to be elevated in a 4-month-old rat livers, but it was a little decreased in 8 and 12-month-old rat livers. The lipid peroxidation levels of microsomal suspension was not shown any significant differences by ages. Lipid peroxidation levels and microsomal cytochrome P450 and NADPH-cytochrome c reductase activity showed a direct correlation (r=0.72 and r=0.64), respectively. The activities of cytochrome P450-dependent aminopyrine-N-demethylase and benzpyrene hydroxylase in rat liver microsomes were increased by ages up to 8-month-old rats and maintained in 12-month-old rats. The correlation between lipid peroxidation levels and these cytochrome-dependent enzyme activities showed a high direct correlation (r=0.97 and r=0.81), respectively.

• Toxicological Research
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• 제4권1호
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• pp.13-22
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• 1988

The inhibitory effect of three polyacetylene compounds, panaxydol, panaxynol and panaxytriol isolated from Panax ginseng C.A. Meyer on $CCl_4$induced lipid peroxidation in vivo and in vitro hepatic microsomal lipid peroxidation induced by ADP-$Fe^{3+}$, NADPH and NADPH-cytochrome P-450 reductase were investigated. Their effects on lowering the lipid peroxide levels both in serum and liver and lowering the serum enzyme (GOT, GPT, LDH) activities without the $CCl_4$-induction were also determined. Male ICR mice were pretreated i.p. with polyacetylene compounds or DL-${\alpha}$-tocopherol before administration of $CCl_4$ i.p. and 20 hr after the administration of $CCl_4,$ serum and liver were analyzed. Hepatic microsome was isolated and used for the in vitro NADPH-dependent lipid peroxidation system. Except for panaxynol, treatment with polyacetylenes to control mice did not reduce the levels of lipid peroxides and serum enzyme activities. Panaxynol itself inhibited lipid peroxidation in the liver of normal mice. Polyacetylene compounds protected from the $CCl_4$-induced hepatic lipid peroxidation and lowered serum lipid peroxide levels. Polyacetylenes also inhibited the in virto hepatic microsomal lipid peroxidation in a dose-dependent manner. The results suggest that panaxydol, panaxynol and panaxytriol seem to be the antioxidant components which contribute the anti-aging activities of Panax ginseng C.A. Meyer.

• Toxicological Research
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• 제3권2호
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• pp.97-110
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• 1987

The effects of 5 novel hepatotrophic agents, dithiol malonate derivatives (DMDs; DMD1-DMD5), on the liver microsomal lipid peroxidation induced by carbon tetrachloride $(CCl_4)$ and the correlations with the changes of microsomal electron transport system were investigated. All DMDs were found to inhibit the lipid peroxidation induced by $CCl_4$ in mice and rats as well in vitro liver microsomal system. Therefore, each DMD seemed to have direct mode of action on liver microsomes to inhibit the lipid peroxidation. As an ex vivo study, the induced lipid peroxidation by $CCl_4$ and the changes in electron transport system were determined with liver microsomes obtained from rats chronically treated with DMDs for 7 days. The induced lipid peroxide contents in liver microsomal system were lower in DMD1, DMD2 and DMD3 treated group, but higher in DMD4 and DMD5 group when compared to the control group. Cyt. p.450 contents in the microsomes were decreased by the treatment with DMD1, DMD2 and DMD3, but increased significantly by DMD4 with great extent and by DMD5 with less extent. The cyt. p-450 isozymes induced by treatment of DMD4 and DMD5 were identified as 3-methylcholanthrene (MC) type. The NADPH cyt. -C reductase activities of the microsomes treated with DMD1, DMD2, DMD4 and DMD5 were increased in the range of around 20% to 50%, but decreased with DMD3, All DMDs increased dyt. $-b_5$ content and did not alter NAdH-cyt, $-b_5$ reductase activities in the microsomes. In summary, the 5 novel hepatotrophic agents (DMDs) markedly protected against lipid peroxidation induced by $CCl_4$ in vivo and in vitro possibly through the mechanism of direct action on the liver microsomes. The degree of inhibition produced by DMDs on lipid peroxidation induced by $CCl_4$ seemed to coincide rather with cyt. p-450 contents than with other components of liver microsomal electron transport system including NADPH-cyt, -C reductase.

• Biomolecules & Therapeutics
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• 제2권2호
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• pp.141-148
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• 1994

This study was done to determine whether specific alterations exist in hepatic microsomal function after varying periods of ischemia (IS) and reperfusion (RP) during microsomal lipid peroxidation occurs. Rats were pretreated with $\alpha$-tocopherol to inhibit lipid peroxidation or with vehicle (soybean oil). Control animals were time-matched sham-ischemic animals. Four groups of animals were studied: Group 1 (sham), group 2 (30 mins IS), group 3 (60 mins IS) and group 4 (90 mins IS). After 1, 5 or 24 hr of reperfusion, liver microsomes were isolated and cytochrome P-450s were studied. In all vehicle-treated ischemic rats, serum ALT levels peaked at 5 hr and were significantly reduced by $\alpha$-tocopherol pretreatment. Similarly, microsomal lipid peroxidation was elevated in all vehicle-treated ischemic animal groups, but this elevation was prevented by $\alpha$-tocopherol pretreatment. Cytochrome P-450 content was significantly decreased in both group 3 and group 4. In all vehicle-treated ischemic animal groups, aminopyrine N-demethylase activity was significantly decreased for the entire reperfusion period. $\alpha$-Tocopherol inhibited reductions of cytochrome P-450 content and aminopyrine N-demethylase activity at both 1 hr and 5hr of reperfusion but did not affect the reduced levels of cytochrome P-450 content and aminopyrine N-demethylase activity at 24 hr of reperfusion. Aniline p-hydroxylase activity was significantly decreased in group 4, whereas it was increased in group 3. These decreases and increases were prevented by $\alpha$-tocopherol pretreatment. Our finding suggests that abnormalities in microsomal drug metabolizing function occur during hepatic ischemia and reperfusion in vivo and this is attributed to microsomal lipid peroxidation.

• 대한수의학회지
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• 제44권2호
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• pp.185-193
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• 2004

The effects of membrane lipid peroxidation and retinyl palmitate on rat liver microsomal functions were investigated in vitro. Rat liver homogenates exposed to oxygen tension for 0, 3, 6, 9 or12 hours and lipid peroxidation levels were evaluated by the measurements of fluorescence intensity, malondialdehyde (MDA) and retinyl palmitate. The fluorescence intensity of homogenates and microsomes were elevated and retinyl palmitate concentrations were decreased. But the concentration of MDA was not affected to exposure time. Therefore, fluorescence intensity and retinyl palmitate concentration were used to analyze the correlation between lipid peroxidation and microsomal functions. To investigate the liver microsomal functions, the microsome was isolated from rat liver homogenates exposed to oxygen. The concentration of cytochrome P450 and the activity of NADPH-cytochrome P450 reductase in liver microsomes were gradually decreased with increasing the exposure time. The correlation between fluorescence intensity of microsomes showed a very high inverse correlation of -0.97 and -0.93, respectively. The decrease of cytochrome P450 concentration was due to the regeneration of cytochrome P450 to cytochrome P420. Also, the activities of cytochrome P450-dependent aminopyrine demethylase and benzpyrene hydroxylase of liver microsomes were gradually decreased with increasing the exposure time. The correlation with fluorescence intensity of microsome showed a high inverse correlation of -0.97 and -0.91, respectively. The retinyl palmitate concentrations of rat liver homogenates were decreased with increasing the exposure time. The decrease of retinyl palmitate concentration was followed by a low concentration of cytochrome P450 and activity of NADPH-cytochrome P450 reductase. The correlation indicated high direct correlation of 0.92 and 0.93, respectively. The decrease of retinyl palmitate concentration was also accompanied by the reduction of aminopyrine demethylase and benzpyrene hydroxylase activities. The correlation was analyzed a high direct correlation of 0.90 and 0.85, respectively. In conclusion, these studies have shown that the membrane lipid peroxidation of rat liver microsome proportionally decreased microsomal enzyme activities in vitro experiments.

• 한국환경성돌연변이발암원학회지
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• 제15권2호
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• pp.140-147
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• 1995

For studying the effect of different dietary fats on carcinogenesis, fatty acid composition of membrane and lipid peroxidation were measured. Male Sprague-Dawley rats were fed on diet containing 15%(w/w) beef tallow or soybean oil. A single dose of 50 mg 2-AAF/kg B.W. was injected i.p. in each diet group 10 times. Rats were sacrifled after 1, 5, 10, and 15 weeks from the first injection. By 2-AAF injection, !ipid peroxidation increased slightly compared to control group. The rats fed on different fats had similar MDA production and those fed on soybean oil had slightly higher free radical concentration measured by ESR. In young rats, iipid peroxidation level was high and hydroxy radical production was higher in soybean oil group than in beef tallow group. With age, the lipid peroxidation values were decreased initially then increased. The fatty acid composition in microsomal membrane was reflected by dietary fatty acid composition. In soybean oil group, monoenoic acid was lower and polyunsaturated fatty acid was higher than beef tallow group. Linoleic acid contents showed the most discrepancy among groups. By 2-AAF treatment, iinoleic acid content and unsaturation index increased in soybean oil group. But in beef tallow group, there was no difference in fatty acid contents.

• 대한약리학회지
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• 제18권1호
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• pp.55-63
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• 1982

Lipid peroxidation is the reaction of oxidative deterioration of polyunsaturated lipids and this peroxidation involves the direct reaction of oxygen and lipid to form free radical intermediates, which can lead to autocatalysis. As results of the extensive studies on the lipid peroxidation by many authors, the relationship between lipid peroxidation and the drug metabolizing system as well as the actions of free radicals on the peroxidation was reasonably well known. For a long time, the mechanism of hepatotoxicity of $CCl_4$ was not clearly understood. However, it is now quite well established that $CCl_4$ is activated in vivo to a free radical which is a highly reactive molecule. Therefore, lipid peroxidation which induces the reduction of cytochrome P-450 and aminopyrine demethylase activity is known as decisive event of $CCl_4$ hepatotoxicity. On the other hand, it was also reported that singlet molecular oxygen produces lipid peroxidation in liver microsomes. In this study the effects of benzoyl peroxide on the lipid peroxidation and drug-metabolizing enzyme were examined. Benzoyl peroxide mixed with starch and phosphates etc. is usually used as a food additive for flour bleaching and maturing purpose because of its oxidative property. Albino rats were used for the experimental animals. Benzoyl peroxide was suspended in soybean oil and sesame oil and administered intraperitoneally or orally. TBA value and aminopyrine demethylase activity were determined in liver microsomal fraction and serum. The results were summerized as following. 1) Body weights of animals administered benzoyl peroxide suspension were decreased while that of oil administered group were increased. 2) The activity of aminopyrine demethylase was generally decreased in animals administered oil suspension of benzoyl peroxide. Furthermore, the marked reduction of the enzyme activity was observed in animals administered benzoyl peroxide intraperitoneally. 3) Generally, microsomal TBA values as well as serum TBA were significantly elevated in benzoyl peroxide group in comparison with the control group. However, the more remarkable increase of serum TBA than microsomal TBA was observed in animals administered orally for 6 days. 4) Specifically, the changing pattern of TBA value was notable in serum rather than in liver microsome by intraperitoneal administration of benzoyl peroxide.

• Journal of Nutrition and Health
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• 제38권5호
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• pp.386-394
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• 2005

Effects of root, stem and leaf extract of sancho (Zanthoxylum schinifolium) on the inhibition of lipid peroxidation in the hepatic microsome of rat, DPPH radical scavenging activity and activated partial thromboplastin times (APTT) were examined in vitro. The highest inhibition of hepatic microsomal lipid peroxidation was observed by ethyl acetate fraction than that of methylene chloride fraction of the root and stem extracts. The high inhibition of lipid peroxidation was determined in the leaf, the root and the stem in order. The DPPH radical scavenging activity of ethyl acetate fraction was higher than that of n-butanol fraction and it was similar to the root and the steam extract. It was similar to the inhibition of hepatic microsomal lipid peroxidation. The DPPH radical scavenging activity was the highest in 2.500mg/mL of ethyl acetate fraction and it was 4.4 fold higher than that of $\alpha-tocopherol$, as an antioxidant standard. The DPPH radical scavenging activity was dependent on the extract concentration in the range of 0.125-5.000 mg/mL. The throm-boplastin times were higher than that of n-butanol fraction and it was similar to the root and the steam extracts. The leaf extract showed the highest antithrombogenic effect followed by the stem and then the root extract. The activated partial thromboplastin times were ependent on the extract concentration in the range of 0.100-2.000 mg/mL. Consequently, the effects of antioxidative, DPPH radical scavenging activity and antithrombogenic of Z. schinifolium was observed due to the inhibition of lipid peroxidation and the DPPH radical scavenging activity by methylene chloride, n-butanol and ethyl acetate fraction of the leaf extract. (Korean J Nutrition 38(5): 386 - 394, 2005)

• 고려인삼학회:학술대회논문집
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• 고려인삼학회 1988년도 학술대회지
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• pp.81-86
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• 1988

고려인삼에서 분리한 폴리아세틸렌 성분인 파낙시돌, 파낙시놀과 파낙시트리올의 사염화탄소로 유도된 마우스와 흰주의 지질과 산화와 효소적 또는 비효소적으로 유도된 시험관내 과산화 지질 형성에 미치는 영향을 관찰하였다. 정상 또는 사염화탄소 처리된 마우스와 흰쥐에 대한 폴리아세틸렌의 효과를 혈청과 간 과산화 지질수준과 혈청효소 (GOT, GPT, LDH) 활성을 측정함으로써 관찰하였다. 간 마이크로좀 내 cytochrome P-450 함량과 aniline hydroxylase와 aminopyrine demethylase 활성도 측정되었다. 정상 마우스에 폴리아세틸렌을 처리한 경우 파낙시놀의 경우를 제외하곤 간과 혈청의 과산화 지질 형성과 혈청효소들의 활성에 변화가 없었으며, 파낙시놀은 간의 지질 과산화를 억제하였다, 폴리아세틸렌 성분들은 사염화탄소로 유도된 간의 과산화지질형성에 대한 보호작용을 나타내었고, 혈청지질과산화 수준을 낮추었다. 또한 사염화탄소로 유도된 LDH의 혈액내 유출에 대한 보호작용이 있으나, 혈청 GOT와 GPT 수준엔 영향을 주지 않았다. 사염화탄소는 cytochrome P-450 함량과 aniline hydroxylase, aminopyrine demethylase 활성을 낮추었으며, 이 경우 폴리아세틸렌은 효과를 나타내지 못하였다. 반면, 사염화탄소 없이 폴리아세틸렌만 처리한경우, 파낙시돌과 파낙시놀은 aniline hydroxylase를 세폴리아세틸렌성분은 aminopyrine demethylase를 유도하였으며, cytochrome P-450엔 영향을 주지 않았다. 시험관내 간 마이크로좀의 지질 과산화는 폴리아세틸렌 첨가시 농도에 비례하여 억제되었다.