• Toxicological Research
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• 제22권3호
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• pp.275-282
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• 2006

In previous our studies, we have reported that eugenol derived from Eugenia caryophyllata(Myrtaceace) exhibits acute N-methyl-D-aspartate(NMDA)- and oxygen/glucose deprivation-induced neurotoxicity in primary cortical cultures and protects hippocampal neurons from global ischemia. In this study, we investigated whether the extracts and fractions of E. caryophyllata or eugenol shows the neuroprotective effects against delayed neuronal injury evoked by NMDA or ${\alpha}$-amino-3-hydroxy-5-methylisoxazole propionate(AMPA), and oxidative damage induced by arachidonic acid-, hydrogen peroxide-, $FeCl_2$/ascorbic acid-, and buthionine sulfoximine(BSO) in primary cortical cultures. We examined the neurotoxicity of eugenol itself in cultures and inhibitory effect of eugenol on NMDA- or kainate(KA)-induced convulsion in BALB/c mice. Each water, methanol extract and methanol fraction of E. caryophyllata was significantly attenuated NMDA-induced delayed neurotoxicity, respectively. Eugenol exhibited a significant inhibitory action against the convulsion evoked by NMDA and KA, and reduced delayed or brief neurotoxicity induced by NMDA, AMPA, and various oxidative injuries. These results suggest that eugenol derived from E. caryophyllata may contribute the neuroprotection against delayed-type excitotoxicity and excitotoxins-mediated convulsion through the amelioration of oxidative stress.

• Toxicological Research
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• 제27권3호
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• pp.185-190
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• 2011

Di-(2-ethylhexyl)-phthalate (DEHP), the most widely utilized industrial plastizer and a ubiquitous environmental contaminant, can act on peroxisome proliferators-activated nuclear hormone receptor family (PPAR) isoforms. To understand the contribution of sphingolipid metabolism to DEHP-induced hepatotoxicity, effect of DEHP exposure on activities of sphingolipid metabolic enzymes in rat liver was investigated. DEHP (250, 500 or 750 mg/kg) was administered to the rats through oral gavage daily for 28 days. The activities of acidic and alkaline ceramidases were slightly increased in 250 mg/kg DEHP-administered rat livers and significantly elevated in 500 mg/kg DEHP-administered ones, although the level of 750 mg/kg DEHP-administered ones was not increased. Neutral ceramidase, acidic and neutral sphingomyelinases, sphingomyeline synthase and ceramide syhthase were not changed at all by DEHP exposure. Therefore, acidic and alkaline ceramidases might play important roles in DEHP-induced hepatotoxicity.

• Toxicological Research
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• 제26권3호
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• pp.185-192
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• 2010

Isaria sinclairii (Cicada Dongchunghacho) was studied as a potential crude natural food in powdered form. The role of tissue fatty acids in relation to the anti-obesity effects of I. sinclairii (IS) was examined by feeding the powder to SD rats ad libitum at 0, 1.25, 2.5, 5 and 10% (calculated about 8 g/kg) of the feed for a period of 3 months and 6 months. The fatty acid composition profile as indicated GC-MS, showed significantly slight dose-dependent increases in the levels of unsaturated fatty acids, particularly, arachidonic acid (C20: 4n6), oleic acid, linoleic acid, eicosadienoic acid, eicosapentaenoic acid (EPA) (C20: 5) concentration in the the ad libitum IS-fed groups compared to the control group in SD abdominal fat over 6 month period. Over viewing of the SD and Ob mice treated Isaria sinclairii powder; there were increases in the single (mono) unsaturated fatty acids ratio but decreases in polyunsaturated fatty acid. In IS-fed groups in proportion to the treatment period, this Dongchunghacho also induced an increase in the level of same result of unsaturated fatty acid in C57BL/6 obese (ob/ob) mice over a 6-month period treatment compared to those given 10% dry mulberry leaf powder (ML) or silkworm powder mixed with the standard diet.

• Toxicological Research
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• 제23권2호
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• pp.165-172
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• 2007

Glycyrrhizae Radix, the dried roots of Glycyrrhiza glabra or Glycyrrhiza uralensis Fischer(Legumino-sae), has been used as a medicine for treatment of imflammation, arthritis, respiratory ailment, skin diseases and liver problems. The purpose of this study was to examine the effect of 70% ethanol extract, 18-${\beta}$-glycyrrhetinic acid, glycyrol and carbenoxolone disodium from Glycyrrhizae Radix on gastritis and gastric cancer. Using these materials, we tested antibacterial activity against Helicobacter pylori, antigastritic activity for HCI-ethanol-induced gastric lesion and the pylorus ligated gastric secretion with rats, and cell viability in gastric cancer cell. 18-${\beta}$-glycyrrhetinic acid and carbenoxolone disodium decreased the volume of gastric secretion and acid output in pylorus ligated rats. Also, carbenoxolone disodium had a strong effect of antibacterial activity on H. pylori. In addition 18-${\beta}$-glycyrrhetinic acid and glycyrol reduced cell viability in human gastric cancer cells(AGS and SNU638 cell) in dose-dependent manner. The reduction of total acid output and gastric secretion as well as the anti-bacterial activity against H. pylori might account for the antigastritic effects of carbenoxolone disodium.

• 한국미생물·생명공학회지
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• 제28권3호
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• pp.152-155
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• 2000

곰팡이 Gibberella fujikuroi ATCC12616을 mutagen N-methyl-N-nitro-N-nitrosoguanidine과 hydroxylamine으로 처리하여 지베렐린 생산수률이 가장 높은 변이주 G. fujikuroi G-26을 선별하였다 변이주 G.fujikuroi G-36는 모균주 G.fujikuroi ATCC 12616 과 비교하여 볼 때 지베렐린 생산수율이 약 32% 향상된 것으로 관찰 되었다 이 균주를 액체배지에서 발효시키면 주 탄소원으로 sucrose를 사용할 때 높은 생산성을 나타내었으며 초기배지 pH와 온도는 각각 pH 4.0$ 28^{\circ}C$조건이 가장 좋았다 배양온도를 $30^{\circ}C$에서 3일 배양후 $20^{\circ}C$로 낮추어 7일간 배양하면 130mg/l의 가장 높은 지베렐린이 생성됨을 알았다.

• 한국환경성돌연변이발암원학회지
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• 제8권1호
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• pp.13-21
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• 1988

Mutagenic actions of aflatoxin B$_1$ (AFB$_1$) in the presence of various concentrations of L-ascorbIc acid (AA) in Salmonella typhimurium strains TA 100 and TA98 were studied. Spontaneous revertants per plate of the tester strains TA100 and TA98 were 121-125 and 25-30 with or without S9 mix, respectively. The negative controls used in the study did not show any mutagenesis in the tester strains. AFB$_1$ revealed strong mutagenicity at the dose levels of 0.05, 0.1 and 0.25 ${\mu}$g/plate with metabolic activation system in both strains. However, it showed a toxic effect when the levels were more than 0.5 ${\mu}$g/plate. When lower concentrations of AA (5-20 ${\mu}$g/plate) were added to AFB$_1$ in the Ames assay system with S9 mix the mutagenic action of AFB$_1$ decreased in both strains. About 70-90% of mutagenicity of AFB$_1$ disappeared in strain TA100 when 20${\mu}$g of AA was added to 0.05 ${\mu}$g of AFB$_1$. The inhibitory effect was greatly increased by the addition of higher concentrations of AA to AFB$_1$ in TA100 strain. The mutagenicity of AFB$_1$ was completely inhibited when 100 ${\mu}$g and 500 ${\mu}$g of AA were added to 0.05 ${\mu}$g and 0.1 ${\mu}$g of AFB$_1$, respectively, However, this protective effect of AA on AFB$_1$ mediated mutagenesis was less effective in TA98 strain than that in TA100.

• 한국환경성돌연변이발암원학회지
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• 제16권1호
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• pp.13-18
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• 1996

One mechanism of free-radical production by ethanol is suggested to be through the intracellular conversion of XDH to XO by increased ratio of NADH to NAD. The major mechanism for physiological compensation of cytosolic NADH/NAD balance is the malate/aspartate shutfie. Therefore, it is important to develop the method to improve the efficiency of malate/aspartate shuttle in ethanol metabolism. In the present study, various amino acids and organic acid involved in the shuttle were tested for their functional efficiency in modulating shuttle in the ethanol-perfused rat liver. The rate of ethanol oxidation in the liver perfused with aspartate alone or aspartate in combination with pyruvate, respectively, was increased by about 10% compared to control liver, but not in the tissues perfused with glummate, cysteine or pyruvate alone. Though glummate, cysteine and pyravate did not affect the ethanol oxidation significanfiy, they showed some suppresive effect on the ethanol-induced radical generation monitored by protein carbonylation analysis. Among the tested components, aspartate is confirmed to be the most efficient as a metabolic regulator for both ethanol oxidation and ethanol-induced oxidative stress in our perfusion system. These effects of aspartate would result from NAD recycling by its supplementation through the coupled aspartate aminotransferase/malate dehydrogenase reactions and the malate-aspartate shuttle.

• Toxicological Research
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• 제20권3호
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• pp.263-272
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• 2004

This study was to investigate single and repeated-dose toxicities of DFA IV, a new candidate of nutraceutical which has preventive effect on anemia and osteoporosis. In single-dose oral toxicity study, the test article were administered once by gavage to rats at dose level of 0, 2,000 and 5,000 mg/kg. No dead animal, abnormal sign and abnormal necropsy finding was found in control and treated groups. Thus the approximate lethal dose of DFA IV was considered to be higher than 5,000 mg/kg in rats. In four week repeated dose oral toxicity study, the test article was administered once daily by gavage to rats at dose levels of 0, 500, 1,000 and 2,000 mg/kg. No abnormality was observed in mortality, clinical findings, body weight changes, food and water consumptions, opthalmoscopic findings, hematological findings, necropsy findings, organ weights and histopathological findings. In urinalysis, specific gravity was increased in 2,000 mg/kg groups of male rats. In serum biochemical analysis, creatine phosphokinase was increased in all treatment groups of male rats. These increases in urine specific gravity and serum creatine phosphokinase activity were not accompanied with related signs such as histopathological changes or clinical findings. In conclusion, four week repeated oral dose of DFA IV to rats did not cause apparent toxicological change at the dose of 500, 1,000 or 2000 mg/kg body weight. Thus it is suggested that no-observed-adverse-effect level (NOAEL) of DFA IV in rats would be 2,000 mg/kg/day body weight.

• Toxicological Research
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• 제28권1호
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• pp.11-18
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• 2012

The aim of this study was to evaluate the single oral dose toxicity of Bupleuri Radix (BR) aqueous extracts, it has been traditionally used as anti-inflammatory agent, in male and female mice. BR extracts (yield = 16.52%) was administered to female and male ICR mice as an oral dose of 2,000, 1,000 and 500 mg/kg (body weight) according to the recommendation of Korea Food and Drug Administration (KFDA) Guidelines. Animals were monitored for the mortality and changes in body weight, clinical signs and gross observation during 14 days after dosing, upon necropsy; organ weight and histopathology of 14 principal organs were examined. As the results, no BR extracts treatment related mortalities, clinical signs, changes on the body and organ weights, gross and histopathological observations against 14 principal organs were detected up to 2,000 mg/kg in both female and male mice, except for soft feces and related body weight decrease detected in male mice treated with 2,000 mg/kg. Therefore, $LD_{50}$ (50% lethal dose) and approximate LD of BR aqueous extracts after single oral treatment in female and male mice were considered over 2000 mg/kg, respectively. Although it was also observed that the possibilities of digestive disorders, like soft feces when administered over 2,000 mg/kg of BR extracts in the present study, these possibilities of digestive disorders can be disregard in clinical use because they are transient in the highest dosages male only.

• Toxicological Research
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• 제16권3호
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• pp.201-209
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• 2000

In association with the international validation program to establish a rodent uterotrophic assay, we conducted preliminary uterotrophic assay proposed by GECD using immature female rats. In the present study, oral and subcutaneous routes were chosen to compare the effects of estrogenic com-pounds in the two dosing regimens. The reference compound ethinyl estradiol (EE) and the antagonist ZM189154(ZM) were administered by gavage or subcutaneously (s.c.) to immature female SD rats from 20 to 22 days of age. For each study, sixty-six female rats were randomly assigned to eleven groups: Untreated control, EE 0,0.01, 0.03, 0.1, 0.3, 1.0,3.0 and 10.0 $\mu\textrm{g}$/kg, EE 3.0 $\mu\textrm{g}$/kg(gavage)/0.3 $\mu\textrm{g}$/kg(s.c) & ZM 0.1 mg/kg, and EE 3.0 $\mu\textrm{g}$/kg(gavage)/0.3 $\mu\textrm{g}$/kg (s.c) & ZM 1.0 mg/kg. There were no treatment-related changes in clinical signs, body weights, food consumption, and necropsy findings in any groups of two studies. The wet and blotted uterus weights increased dose-dependently. Histopathological examination revealed that diameter of uterine duct, height of uterine luminal epithelium. and height oj vaginal epithelium increased dose-dependently. The proliferating cell nuclear antigen (PCNA) immunoreactive cells were increased in number dose-dependently. The estrogenic effects observed in the present studies occurred at $\geq$ 0.3 $\mu\textrm{g}$/kg of oral dose and $\geq$ 0.1 $\mu\textrm{g}$/kg of s.c. dose. An antagonistic effect of ZM against EE was found in both uterus weight and histopathological parameters. From the results obtained, it can be concluded that dose-dependence of the uterotrophic assay using EE and ZM was well demonstrated by gavage and subcutaneous administration and that the estrogenic effects of EE by s.c. dose were higher than those by gavage administration. In addition, blotted uterus weight was more sensitive than wet uterus weight and vaginal epithelial height was found to be the most sensitive parameter among the parameters examined.