• Archives of Pharmacal Research
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• v.26 no.7
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• pp.526-531
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• 2003

KR-31378 is a new drug candidate intended for the use in the prevention of ischemia-reperfusion damage. The objective of this preformulation study was to determine the physicochemical properties of KR-31378. The n-octanol to water partition coefficients of KR-31378 were 0.0504 at pH 3 and 0.8874 at pH 10. Accelerated stability of KR-31378 in solution and solid state was studied at 5, 40, $60^{\circ}C$. The stability testing indicated that the t90 for the drug in solid was estimated to be 2 years and 128.6 days at $25^{\circ}C$, while the that in aquesou solution was 68.6 days at $25^{\circ}C$. The KR-31378 was also found to be unstable under the relative humidity of 76%, probably because of the hygroscopic nature of the drug. In order to study compatibility of KR-31378 with typical excipients, potential change in differential scanning calorimetry spectrum was studied in 1:1 binary mixtures of KR-31378 and Aerosil, Avicel, Eudragit, lactose, PEG, talc, CMC, PVP, starch. As a result, CMC, PVP, and starch were found to be incompatible with KR-31378, indicating the addition of these excipients may complicate the manufacturing of the formulation for the drug. Particle size distribution of KR-31378 powder was in the size range of 9-93 $\mu$ m with the mean particle size of 37.9 $\mu$ m. The flowability of KR-31378 was apparently inadequate, indicating the granulation may be necessary for the processing of the drug to solid dosage forms. Crystallization of the drug with a number of organic solvents did not lead a crystalline polymorphism. In addition, dissolution of the drug from the powder was adequately rapid at $37^{\circ}C$ in water.

• The Korean Journal of Physiology and Pharmacology
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• v.8 no.2
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• pp.95-100
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• 2004

Ischemic preconditioning (IPC) has been accepted as a heart protection phenomenon against ischemia and reperfusion (I/R) injury. The activation of ATP-sensitive potassium $(K_{ATP})$ channels and the release of myocardial nitric oxide (NO) induced by IPC were demonstrated as the triggers or mediators of IPC. A common action mechanism of NO is a direct or indirect increase in tissue cGMP content. Furthermore, cGMP has also been shown to contribute cardiac protective effect to reduce heart I/R-induced infarction. The present investigation tested the hypothesis that $K_{ATP}$ channels attenuate DNA strand breaks and oxidative damage in an in vitro model of I/R utilizing rat ventricular myocytes. We estimated DNA strand breaks and oxidative damage by mean of single cell gel electrophoresis with endonuclease III cutting sites (comet assay). In the I/R model, the level of DNA damage increased massively. Preconditioning with a single 5-min anoxia, diazoxide $(100\;{\mu}M)$, SNAP $(300\;{\mu}M)$ and 8-(4-Chlorophenylthio)-guanosine-3',5'-cyclic monophosphate (8-pCPT-cGMP) $(100\;{\mu}M)$ followed by 15 min reoxygenation reduced DNA damage level against subsequent 30 min anoxia and 60 min reoxygenation. These protective effects were blocked by the concomitant presence of glibenclamide $(50\;{\mu}M)$, 5-hydroxydecanoate (5-HD) $(100\;{\mu}M)$ and 8-(4-Chlorophenylthio)-guanosine-3',5'-cyclic monophosphate, Rp-isomer (Rp-8-pCPT-cGMP) $(100\;{\mu}M)$. These results suggest that NO-cGMP-protein kinase G (PKG) pathway contributes to cardioprotective effect of $K_{ATP}$ channels in rat ventricular myocytes.

• Biomolecules & Therapeutics
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• v.7 no.4
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• pp.362-370
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• 1999

Propolis, a natural resinous compound collected from honey bees, contains many biochemical constituents(wax, flavonoids, phenolic compounds, etc.) and has been used in traditional medicines as early as 300 B.C. It was been demonstrated that ethanol, acetylsalicylic acid, ischemia reperfusion, non-steroidal antiin-flammatory drugs and stress induce gastric lesions by promoting the generation of reactive oxygen metabolites. Therefore, some drugs that are capable of scavenging or inhibiting the generation of reactive oxygen radicals might be expected to prevent the gastric mucosal injury. The aim of this study was 1) to examine the antiulcer effect of propolis, 2) to investigate the mechanism of action by determining gastric acid secretion, lipid per-oxidation, mucus content and proton pump ($H^+$/$K^+$-ATPase) activity on gastric mucus in varios experimental models, and finally, 3) to isolate and identify the pure compounds that exert antiulcer activity. Step 2-1 and 2-3 sub-sub fraction shoed a significant reduction of severity of gastirc damage at the dose of 25 mg/kg in various experimental models. We isolated 4 sub-sub-sub fractions by flash column chromatography of Step 2-1 sub-sub fraction and one sub-sub-sub fraction by recrystalization of Step 2-3 sub-sub fraction. The protective effects of propolis sub-sub-sub fraction manifested sifnificant effects in HCl-ethanol induced gastric erosion model and aspirin induced gastric ulcer model. These results showed that the gastric mucosal protective effect of propolis might result from the increase of mucus secretion, free radical scavenging effect as well as the reduction of acid secretion in accordance with the reduction of $H^+$/$K^+$-ATPase activitv. Three compounds were isolated and identified from sub-sub fraction of propolis which showed antiulcer effects. Subsequently, these compounds were identified as a flavonoid, namely, 2-acetoxy-5,7,-dihydroxy-flavanone, galangin and chrysin.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1996.04a
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• pp.205-205
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• 1996

본 실험은 간장허혈 및 재관류시 야기되는 간장 손상에 대해 vitamin C와 E 각각의 효과와 이들의 병용효과를 알아보고자 하였다. 실험군은 흰쥐에 vitamin E(25mg/kg)를 실험전 3일간 투여한 군, vitamin C(100mg/kg)를 실험 5분전 경정맥주사한 군 및 vitamin C와 E의 병용 투여군등의 3군으로 하여 각각에 허혈을 유발시킨 후 (60분) 재관류 1시간, 5시간에 간세포 손상정도(AI.T, AST, liver wet-weight to dry-weight ratio), 지질과산화(MDA), 담즙분비변동(bile flow, bilirubin, cholate output) 및 약물대사효소계의 변동(cytochrome P$_{450}$, aminopyrine-N-demethylase, aniline p-hydroxylase activity) 등을 관찰하였다. 실험결과로는 허혈 및 재관류로 인한 ALT, AST MDA는 재관류 5시간에 최고치를 이루었으며 이는 vitamin C와 vitamin E의 각각 투여로 억제되었고, 특히 vitamin C와 E의 병용투여로 더욱 현저하게 억제되었다. 간세포 부종의 지표인 liver wet-weight to dry-weight ratio도 vitamin C와 E의 병용투어로 유의성있게 억제되었다. 담즙분비량 및 담즙산량은 vitamin C 투여와 vitamin C와 E 병용투여로 허혈 및 재관류로 감소된 양을 증가시켰고, 특히 vitamin C와 E의 병용투여는 담즙분비량에 있어 현저한 상승을 나타내었다. 허혈 및 재관류로 인한 cytochrome P$_{450}$양의 감소와 aminopyrine N-demethylase 활성의 억제는 vitamin C 투여와 vitamin C와 E의 병용투여에 의해 유의성 있게 증가하였다. 이상의 결과로 보아 vitamin C와 vitamin E는 각각 허혈 및 재관류로 인한 간장손상을 완화시켰으며 특히 vitamin C와 E의 병용투여는 상승적으로 적용하여 간세포손상을 더욱 억제시킴을 알 수 있었다.

• The Journal of Korean Medicine
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• v.28 no.3 s.71
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• pp.216-231
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• 2007

Objectives : Chengsimyeunja-eum and Sunghyangjungi-san are prescriptions used for cerebral infarction clinically; it is known that these formulas reduce ischemic damage. According to previous research data, controlling certain types of glucose is considered to decrease the risk of cerebral infarction. Based on this fact, we investigated the effects of Chengsimyeunja-eum and Sunghyangjungi-san extracts on reperfusion following ischemic damage to diabetic rats, the change of c-FOS and Bax positive neurons in the hippocampus and cerebral cortex and protein through immunohistochemical methods, changes of serum glucose level, serum triglyceride level, and hepatic glucokinase activity. Methods : We induced ischemic damaged in diabetic rats, and the rats were administered Chengsimyeunja-eum and Sunghyangjungi-san extracts. Results : Chengsimyeunja-eum demonstrated significant decrease of c-Fos positive neurons in both hippocampus and cerebral cortex as well as a significant decrease of Bax positive neurons in hippocampus after ischemic damage on diabetic rats and decrease of serum glucose level after ischemic damage on diabetic rats. Sunghyangjungi-san demonstrated significant decreases of c-Fos and Bax positive neurons in both hippocampus and cerebral cortex after ischemic damage on diabetic rats. Conclusions : Chengsimyeunja-eum, effect on glucose level control, has a remarkable effect of protection of neurons not effective on glucose level. Sunghyangjungi-san showed neuroprotective effect through preventing neuronal cell death.

• BMB Reports
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• v.38 no.1
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• pp.111-114
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• 2005

Heat shock proteins (HSPs) are known to protect cells from oxidative stress and other types of injuries. We previously reported the neuroprotective effect of HSP70 following cerebral ischemia and reperfusion using hsp 70.1 knockout (KO) mice. However, the precise role of HSP70 in neuroprotection has not been established yet. The purpose of this study was to investigate the relationship between HSP70 and antioxidant enzymes using hsp 70.1 KO mice. The activities of both SOD-1 and SOD-2 were significantly decreased in hsp 70.1 KO mice than in the wild type (WT) littermates. SOD-1 protein level in the hsp 70.1 KO mice was lower than that of WT. We speculate that HSP70 might be involved in regulation of expression of SOD-1 at the level of transcription or by post-transcriptional modification.

• Journal of Physiology & Pathology in Korean Medicine
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• v.27 no.4
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• pp.446-452
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• 2013

This study was designed to investigate the effects of Angelicae Gigantis and Cynanchum wilfordii Hemsley extract (AAC) on the changes of regional cerebral blood flow (rCBF) and mean arterial blood pressure (MABP) in normal rats, and in the rats with cerebral ischemia induced by middle cerebral artery occlusion, and further to determine the mechanisms. The results were as follows. AAC significantly increased rCBF but significantly decreased MABP in a dose-dependent manner in normal rats. The increase of AAC-induced rCBF was significantly inhibited by pretreatment with methylene blue (0.01 mg/kg, i.p.), an inhibitor of guanylate cyclase, and AAC-induced MABP was decreased by pretreatment with methylene blue. In cerebral ischemics, rCBF was stably improved by AAC (10 mg/kg, i.p.) during the period of cerebral reperfusion, which was contrasted with the findings of rapid and marked increase in the control group. These results suggest that AAC can increase rCBF in the normal state, as well as improve the stability of rCBF in cerebral ischemic state.

• The Korean Journal of Physiology and Pharmacology
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• v.14 no.3
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• pp.127-132
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• 2010

Reactive oxygen species (ROS), which include hydrogen peroxide ($H_2O_2$), the superoxide anion (${O_2}^-{\cdot}$), and the hydroxyl radical ($OH{\cdot}$), are generated as by-products of oxidative metabolism in cells. The cerebral cortex has been found to be particularly vulnerable to production of ROS associated with conditions such as ischemia-reperfusion, Parkinson's disease, and aging. To investigate the effect of ROS on inhibitory GABAergic synaptic transmission, we examined the electrophysiological mechanisms of the modulatory effect of $H_2O_2$ on GABAergic miniature inhibitory postsynaptic current (mIPSCs) in mechanically isolated rat cerebral cortical neurons retaining intact synaptic boutons. The membrane potential was voltage-clamped at -60 mV and mIPSCs were recorded and analyzed. Superfusion of 1-mM $H_2O_2$ gradually potentiated mIPSCs. This potentiating effect of $H_2O_2$ was blocked by the pretreatment with either 10,000-unit/mL catalase or $300-{\mu}M$ N-acetyl-cysteine. The potentiating effect of $H_2O_2$ was occluded by an adenylate cyclase activator, forskolin, and was blocked by a protein kinase A inhibitor, N -(2-[p-bromocinnamylamino] ethyl)-5-isoquinolinesulfonamide hydrochloride. This study indicates that oxidative stress may potentiate presynaptic GABA release through the mechanism of cAMP-dependent protein kinase A (PKA)-dependent pathways, which may result in the inhibition of the cerebral cortex neuronal activity.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.868-869
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• 2005

• Molecules and Cells
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• v.40 no.11
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• pp.837-846
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• 2017

As a component of the neurovascular unit, cerebral smooth muscle cells (CSMCs) are an important mediator in the development of cerebral vascular diseases such as stroke. Epoxyeicosatrienoic acids (EETs) are the products of arachidonic acid catalyzed by cytochrome P450 epoxygenase. EETs are shown to exert neuroprotective effects. In this article, the role of EET in the growth and apoptosis of CSMCs and the underlying mechanisms under oxygen glucose deprivation (OGD) conditions were addressed. The viability of CMSCs was decreased significantly in the OGD group, while different subtypes of EETs, especially 14,15-EET, could increase the viability of CSMCs under OGD conditions. RAPA (serine/threonine kinase Mammalian Target of Rapamycin), a specific mTOR inhibitor, could elevate the level of oxygen free radicals in CSMCs as well as the anti-apoptotic effects of 14,15-EET under OGD conditions. However, SP600125, a specific JNK (c-Jun N-terminal protein kinase) pathway inhibitor, could attenuate oxygen free radicals levels in CSMCs as well as the anti-apoptotic effects of 14,15-EET under OGD conditions. These results strongly suggest that EETs exert protective functions during the growth and apoptosis of CSMCs, via the JNK/c-Jun and mTOR signaling pathways in vitro. We are the first to disclose the beneficial roles and underlying mechanism of 14,15-EET in CSMC under OGD conditions.