• The Korean Journal of Physiology and Pharmacology
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• 제6권4호
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• pp.207-214
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• 2002

The present study was designed to clarify whether tacrine affects the release of catecholamines (CA) from the isolated perfused model of rat adrenal gland or not and to elucidate the mechanism of its action. Tacrine $(3{\times}10^{-5}{\sim}3{\times}10^{-4}\;M)$ perfused into an adrenal vein for 60 min inhibited CA secretory responses evoked by ACh $(5.32{\times}10^{-3}\;M),$ DMPP (a selective neuronal nicotinic agonist, $10^{-4}$ M for 2 min) and McN-A-343 (a selective muscarinic M1-agonist, $10^{-4}$ M for 2 min) in relatively dose- and time- dependent manners. However, tacrine failed to affect CA secretion by high $K^+\;(5.6{\times}10^{-2}\;M).$ Tacrine itself at concentrations used in the present experiments did not also affect spontaneous CA output. Furthermore, in the presence of tacrine $(10^{-4}\;M),$ CA secretory responses evoked by Bay-K-8644 (an activator of L-type $Ca^{2+}$ channels, $10^{-4}\;M),$ but not by cyclopiazonic acid (an inhibitor of cytoplasmic $Ca^{2+}-ATPase,\;10^{-4}\;M),$ was relatively time-dependently attenuated. Also, physostigmine $10^{-4}\;M),$ given into the adrenal gland for 60 min, depressed CA secretory responses evoked by ACh, McN-A-343 and DMPP while did not affect that evoked by high $K^+.$ Collectively, these results obtained from the present study demonstrate that tacrine greatly inhibits CA secretion from the perfused rat adrenal gland evoked by stimulation of cholinergic (both nicotinic and muscarinic) receptors, but does fail to affect that by direct membrane-depolarization. It is suggested that this inhibitory effect of tacrine may be exerted by blocking both the calcium influx into the rat adrenal medullary chromaffin cells without $Ca^{2+}$ release from the cytoplasmic calcium store, that is relevant to the cholinergic blockade. Also, the mode of action between tacrine and physostigmine in rat adrenomedullary CA secretion seems to be similar.

• 약학회지
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• 제49권1호
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• pp.103-108
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• 2005

Tacrine analogues for degenerative brain disease treatments have been designed. A series of diazaanthrine derivatives as novel analogues of tacrine has been prepared through the alkyl substitution and the ring expansion. They were expected to retain anti-inflammatory activity by inhibition of prostaglandin production with reduction of side effect as the selective prostaglandin synthase inhibitor. Prostaglandin synthase expression is associated with the deposition of beta-amyloid protein in neuritic plaques in brain inflammation. Therefore selective prostaglandin synthase blockade is important for the prevention and treatment of alzheimer's disease. To evaluate inhibitory effect of prostaglandin synthase, synthetic tacrine derivatives were screened with accumulation of prostaglandin biosynthesis by lipopolysaccharide in aspirin-treated murine macrophage cell. Most of synthetic compounds have shown significant prostaglandin synthase activities in vitro screening with $84.3{\sim}33.6\%$ inhibition of the prostaglandin $E_2$ production at $10\;{\mu}g/ml$.

• 한국응용과학기술학회지
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• 제29권4호
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• pp.552-560
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• 2012

약물 전달 시스템은 약물의 방출 프로파일, 흡수, 분배 및 제품의 효율성과 안전성, 환자의 편의성과 협조를 향상시키기 위한 제거를 개선하는 명백하게 보호화된 공식화 기술이다. 가장 일반적으로 쓰이는 transdermal 시스템은 다양한 종류의 기술을 사용하는 skin patch다. 다른 투약 방법과 달리, transdermal 시스템은 장기간 사용이 가능하다. 또한, 부작용이 생길 경우, 약물 투약의 중단이 가능하다. karaya gum and locust bean gum(LBG)/water-soluble chitosan oligomer(WSCO)과 같은 Polysaccharide를 TDS의 기본 물질로 선택하였다. 또한, 이 polymers들은 tacrine 물질, 강화제로 규정되어진다. 이러한 polysaccharide 중에서, karaya gum matrix의 침투율은 lipophilic drug in vitro 와 같은 tacrine 내에서 가장 빠르다. 우리는 glycerin, PEG 400, and PEG 800를 강화제로 사용하였다. 그러므로, transdermal의 tacrine 흡수율은 vehicle 구성을 바꿈으로써, 혹은 침투 강화제를 사용함으로써 향상되었을 것이다. 특히, vehicle이 스스로의 효과를 강화하는 것과 더불어, vehicle에 강화제를 첨가함으로써 높은 침투 효율이 얻어질 것으로 기대된다.

• 약학회지
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• 제46권3호
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• pp.185-191
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• 2002

Alzheimer's disease (AD) involves neuronal degeneration with impaired cholinergic transmission, particularly in areas of the brain associated with learning and memory. Several cholinesterase inhibitors are widely prescribed to ameliorate the cognitive deficits in AD patients. In an attempt to examine if tacrine and donepezil, two well-known cholinesterase inhibitors, exhibit additional pharmacological actions in primary cultured rat cortical cells, we investigated the effects on neuronal injuries induced by glutamate or N-methyl-D-aspartate (NMDA), $\beta$-amyloid fragment ( $A_{{beta}25-35)}$), and various oxidative insults. Both tacrine and donepezil did not significantly inhibit the excitotoxic neuronal damage induced by glutamate. However, tacrine inhibited the toxicity induced by NMDA in a concentration-dependent fashion. In addition, tacrine significantly inhibited the $A_{{beta}25-35)}$-induced neuronal injury at the concentration of 50 $\mu$M. In contrast, donepezil did not reduce the NMDA- nor $A_{{beta}25-35)}$-induced neuronal injury. Tacrine and donepezil had no effects on oxidative neuronal injuries in cultures nor on lipid peroxidation in vitro. These results suggest that, in addition to its anticholinesterase activity, the neuroprotective effects by tacrine against the NMDA- and $A_{{beta}25-35)$-induced toxicity may be beneficial for the treatment of AD. In contrast, the potent and selective inhibition of central acetylcholinesterase appears to be the major action mechanism of donepezil.

• 생약학회지
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• 제39권1호
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• pp.68-73
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• 2008

The present study represents the screening of the protective effects of herbal methanolic extracts from Baekdu mountain against tacrine-induced cytotoxicity in HepG2 cells. Tacrine is an acetylcholinesterase inhibitor, and used for the treatment of Alzheimer's disease. However, administration of tacrine for the treatment of Alzheimer's disease results in a reversible hepatotoxicity in 30-50% of patients, consequently limiting clinical use. Therefore, studies for natural products with protective effect on the tacrine-induced hepatotoxicity would be valuable as providing potential therapeutic use. 109 plant sources were collected in Baekdu mountain, and extracted with methanol. These extracts had been screened the protective effects against tacrine-induced cytotoxicity in HepG2 cells at the 100 and 300 ${\mu}g/ml$. Of these, ten methanolic extracts, roots of Ampelosis japonica, aerial parts of Berberis amurensis, aerial parts of Sedum aizoon, aerial parts of Lespedeza tomentosa, aerial parts of Lespedeza juncea, aerial parts of Hypenricum ascyron, stem barks of Syringa reticulata, fruits of Gleditsia japonica, aerial parts of Chamaenerion angustifolium, branches of Ginkgo biloba, showed significant protective effects against tacrine-induced cytotoxicity in HepG2 cells.

• 생약학회지
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• 제38권4호
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• pp.400-402
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• 2007

Tacrine is an acetylcholinesterase inhibitor that is approved for the treatment of Alzheimer's disease. However, tacrine treatment for Alzheimer's disease results in reversible hepatotoxicity in 30-50% of patients, which seriously limits its clinical use. Accordingly, the identification of constituents in natural products that have protective effects on tacrine-induced hepatotoxicity would be valuable. In the present study, an immortalized human hepatoma cell line, HepG2 was employed to screen for agents that protect against tacrine-induced hepatotoxicity. The bioassay-guided fractionation of water extract of Cassiae Semen furnished two anthraquinones, aurantio-obtusin (1) and obtusifolin (2). Compounds 1 and 2 showed hepatoprotective effects with the protection ratio values of 55.3 +/- 0.5% and 41.2 +/- 0.8% at $160{\mu}M$, respectively.

• Archives of Pharmacal Research
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• 제28권12호
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• pp.1376-1380
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• 2005

In this study, ethanolic extracts from 18 seaweed variants were assessed for hepatoprotective activity against tacrine-induced cytotoxicity in Hep G2 cells. Only one of these, Ecklonia stolonifera Okamura (Laminariaceae), a member of the brown algae, exhibited promising hepatoprotective activity. Bioassay-guided fractionation of the active ethyl acetate (EtOAc) soluble fraction obtained from the ethanolic extract of E. stolonifera, resulted in the isolation of several phlorotannins [phloroglucinol (1), eckstolonol (2), eckol (3), phlorofucofuroeckol A (4), and dieckol (5)]. Compounds 2 and 4 were determined to protect Hep G2 cells against the cytotoxic effects of tacrine, with $EC_{50}$ values of 62.0 and 79.2 $\mu$g/mL, respectively. Silybin, a well characterized hepatoprotective agent, was used as a positive control, and exhibited an $EC_{50}$ value of 50.0 $\mu$g/mL. It has been suggested that the phlorotannins derived from marine brown algae might prove useful sources in the development of novel hepatoprotective agents.

• 대한한의학회지
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• 제25권4호
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• pp.1-7
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• 2004

Objective : This study was designed to examine the effects of orally administered Prunus persica water extract (PPE), which is used as herbal medicine, for treatment of Yu Xue (stasis of blood) and tacrine on the basal concentration of extracellular acetylcholine in the hippocampus of rats. Methods: To investigate the effects of PPE and tacrine on concentration of extracellular acetylcholine in the hippocampus of rats, the microdialysis technique, under the same experimental conditions, was used. And we used male Wistar rats which were 7 weeks of age and 210-290 g. PPE was extracted with boiling water, and the rats were anesthetized with pentobarbital Na. Their skulls were exposed and a hole was drilled for implantation of a microdialysis probe. In order to increase the recovery of acetylcholine, a probe with a long membrane was used. One day after surgery, the microdialysis probe was perfused with Ringer's solution at a flow rate of 1.5 l/min. The acetylcholine concentration in dialysis samples was measured by high-performance liquid chromatography (HPLC) with electrochemical detection. AChE activity was measured using the radiometric method, as described by Sherman. Results : The comparative effects of PPE and tacrine on hippocampal extracellular acetylcholine concentration was that these cholinesterase inhibitors produced dose-dependent increases in the extracellular acetylcholine concentration. And the effect of PPE and tacrine on rat brain AChE activity was that PPE produced maximal inhibition at 1 h after administration, when AChE activity was 44% of the intact level. AChE activity gradually recovered thereafter, and reached 78% of the intact level at 12 h after administration. Conclusion : In this study, PPE has a potent activity and a long-lasting effect on the central cholinergic system, in terms of the basal concentration of extracellular acetylcholine in the hippocampus and the AChE activity in the brain of rats. And oral administration of PPE increased dose-dependently the basal concentration of extracellular acetylcholine in the hippocampus of rats. PPE may be one of the more useful cholinesterase inhibitors for the treatment of Alzheimer's disease.

• Archives of Pharmacal Research
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• 제27권9호
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• pp.947-953
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• 2004

The antioxidative and hepatoprotective potentials of two anthraquinones, alaternin (2-hydroxy-emodin) and emodin, to scavenge and/or inhibit hydroxyl radicals generated by the Fenton reaction and to protect tacrine-induced cytotoxicity in human liver derived HepG2 cells were evaluated, respectively. The inhibitory activity on hydroxyl radical generated in a cell-free chemical system (FeSO$_4$/$H_2O$$_2$) was investigated by a fluorescence spectrophotometer using a highly fluorescent probe, 2$^1$,7$^1$-dichlorofluorescein. The hydroxyl radical scavenging activity was determined by electron spin resonance spectroscopy using 5,5-dimethy-1-pyrroline-N-oxide as hydroxyl radicals trapping agents. Tacrine-induced HepG2 cell toxicity was determined by a 3-［4,5-dimethylthiazole-2yl］-2,5-diphenyltertrazolium bromide assay. Although the scavenging activity of alaternin on hydroxyl radical was similar to that of emodin in dose-dependent pat-terns, the inhibitory activity exhibited by the former on hydroxyl radical generation was stron-ger than that of the latter, with $IC_{50}$/ values of 3.05$\pm$0.26 $\mu$M and 13.29$\pm$3.20 $\mu$M, respectively. In addition, the two anthraquinones, alaternin and emodin showed their hepatoprotective activ-ities on tacrine-induced cytotoxicity, and the EC$_{50}$ values were 4.02 11M and 2.37 $\mu$M, respec-tively. Silymarin, an antihepatotoxic agent used as a positive control exhibited the EC$_{50}$ value of 2.00 $\mu$M. These results demonstrated that both alaternin and emodin had the simultaneous antioxidant and hepatoprotective activities.ies.

• 생명과학회지
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• 제22권1호
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• pp.117-125
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• 2012

본 연구는 굴 가수분해물의 간 보호 효과를 확인하는 것을 목표로 하였다. 굴은 많은 기능적 요소를 가지고 있다고 알려져 있으며 특히, 효소에 의해 생산된 가수분해물은 우수한 기능적 물질을 포함한다. 타크린으로 유발한 간세포 독성에 대한 효소별 굴 가수분해물의 보호 효과를 확인하기 위하여 HepG2세포를 이용하여 in vitro상에서 확인하였다. 사용한 샘플은 Neutrase, Flavourzyme, Protamex을 이용하여 효소 가수분해한 것이다. 타크린으로 손상을 유발한 간세포에서는 GOT와 LDH가 증가하게 된다. 굴 효소 가수분해물을 처리한 실험군에서는 아무런 처리를 하지 않은 실험군에 비하여 높은 세포 생존율을 확인할 수 있었다. 또한 GOT와 LDH 역시 감소하는 것을 알 수 있었다. 본 연구를 통하여 타크린 독성에 대한 신약, 식품의 기초 자료를 제공할 수 있을 것으로 기대된다.