• Natural Product Sciences
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• 제6권2호
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• pp.70-72
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• 2000

The effects of coptisine on monoamine oxidase (EC 1.4.3.4; MAO) activity in mouse brain were investigated. Coptisine showed an inhibitory effect on MAO activity with a concentration-dependent manner. Coptisine exhibited 51.0% inhibition of MAO activity at $9\;{\mu}M$. The $IC_{50}$ value of coptisine was $8.7\;{\mu}M$. Coptisine inhibited MAO activity competitively with kynuramine as a substrate. The $K_i$ value of coptisine was $4.1\;{\mu}M$. These results indicate that coptisine functions to regulate the catecholamine content at biologically active sites.

• Natural Product Sciences
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• 제6권1호
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• pp.16-19
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• 2000

Four compounds were isolated from the dichloromethane fraction of Cinnamomi Cortex through bioassay-guided isolation. Their structures were identified as coumarin (1), 3,3-dimethoxy-1-propenyl benzene (2), cinnamic acid (3) and o-methoxy cinnamaldehyde (4) on the basis of spectroscopic data. All four compounds showed inhibitory activities in vitro against monoamine oxidase (MAO) prepared by mouse brain. The $IC_{50}$ values were $41.4\;{\mu}M\;(1),\;110.6\;{\mu}M\;(2),\;252.5\;{\mu}M\;(3)\;and\;83.1\;{\mu}M$ (4), respectively.

• 생약학회지
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• 제34권2호통권133호
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• pp.185-189
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• 2003

We examined the inhibitory activities against monoamine oxidase (MAO) of Morus alba in vitro and in vivo methods. Methanolic extract of M. alba showed significantly inhibitory activities on MAO-A and MAO-B that were prepared from rat brain and liver in vitro. The inhibitory activities were measured by serotonin and benzylamine as substrates, respectively. MAO-A and MAO-B activities were potently inhibited by ethylacetate extracts of M. alba in vitro tests. Those activities in vivo tests have different tendency each other. MAO-A activity was increased by the oral administration of methanolic extract of M. Alba, while, MAO-B activity was decreased. Consequently, we can suggest that M. alba may have the effects on the inhibitory activities against MAO both in vitro and in vivo.

• The Korean Journal of Physiology and Pharmacology
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• 제10권4호
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• pp.207-212
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• 2006

Mitochondrial permeability transition has been shown to be involved in neuronal cell death. Mitochondrial monoamine oxidase (MAO)-B is considered to play a part in the progress of nigrostriatal cell death. The present study examined the effect of MAO inhibitors against the toxicity of 1-methyl-4-phenylpyridinium $(MPP^+)$ in relation to the mitochondrial permeability transition. Chlorgyline (a selective inhibitor of MAO-A), deprenyl (a selective inhibitor of MAO-B) and tranylcypromine (nonselective inhibitor of MAO) all prevented cell viability loss, cytochrome c release, caspase-3 activation, formation of reactive oxygen species and depletion of GSH in differentiated PC12 cells treated with $500\;{\mu}M$$MPP^+$. The MAO inhibitors at $10\;{\mu}M$ revealed a maximal inhibitory effect and beyond this concentration the inhibitory effect declined. On the basis of concentration, the inhibitory potency was tranylcypromine, deprenyl and chlorgyline order. The results suggest that chlorgyline, deprenyl and tranylcypromine attenuate the toxicity of $MPP^+$ against PC12 cells by suppressing the mitochondrial permeability transition that seems to be mediated by oxidative stress.

• 대한의생명과학회지
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• 제10권4호
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• pp.421-427
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• 2004

The possible mechanisms of decreased monoamine oxidase (MAO) A and B activities in cholestatic rat liver were studied. Hepatic and serum MAG activities were determined from the experimental rats with common bile duct ligation (CBDL). The Michaelis-Menten constants in these hepatic enzymes were also measured. The activities of mitochondrial MAO A and B, and mircosomal MAO B as well as their Vmax values were found to be decreased significantly in CBDL plus taurocholic acid (TCA) injected group than in the control group, such as CBDL alone groups. However, their Km values in the experimental groups did not vary. Serum MAO activity increased significantly in the CBDL plus TCA injected group than in the control group. The above results suggest that TCA represses biosynthesis of the MAO in the liver. The elevated activity of the serum MAO is believed to be caused by the increment of membrane permeability ofhepatocytes upon TCA mediated liver cell necrosis.

• Archives of Pharmacal Research
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• 제24권1호
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• pp.51-54
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• 2001

Three varieties of methyl citrate and 1 -methyl malate were isolated from the fruits of Opuntia ficus-indica var. saboten Makino through in vitro bioassay-guided isolation for the inhibition on monoamine oxidase(MAO). The $IC_50$ values for MAO-B of 1-monomethyl citrate, 1,3-dimethy citrate, trimethyl citrate and 1-methyl malate were 0.19, 0.23, 0.61 and 0.25 mM, respectively. However, on MAO-A, their inhibitions showed only marginal activity.

• Natural Product Sciences
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• 제5권4호
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• pp.159-161
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• 1999

The effects of bioactive fractions containing protoberberine alkaloids from Coptis japonica on monoamine oxidase (MAO) activity were investigated. The MAO was obtained from the mitochondrial fraction of mouse brain. The butanol fraction from Coptis japonica was fractionated into separate bioactive fraction (Fr I-IV) by silica gel column chromatography. MAO activity was strongly inhibited by Fr III and IV, which mainly contain protoberberine alkaloids such as berberine, palmatine and coptisine. These results indicated that the protoberberine alkaloids from Coptis japonica had an inhibitory effect on MAO activity.

• Archives of Pharmacal Research
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• 제18권4호
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• pp.271-276
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• 1995

Changes in the distribution of dopamine and its metabolites, activities of monoamine oxidase, and dopamine uptake were studied inhyperglycemic rat striatum. The hyperglycemia was induced by the administration of streptozotocin (STZ, 40 mg/kg, i.p. for 3 days.). The levels of dihydroxyphenylacetic acid (DOPAC) and homovanillic acid were significantly decreased without change in dopamine level in the synatic cleft 14 days after STZ treatment. In the synaptosome, the dopamine level, however, was significanly increased after the treatment. But the DOPAC level in the synaptosome was decreased 14 days after the treatment. The affinity of dopamine uptake was significantly decreased without changes in the velocity 14 days after the treatment. However the response to uptqke inhibitor was unchanged. The striatal monoamine oxidase activities were also decreased in the hyperglycemic state. These results indicate that various parameters of striatal dopamine activities were decreased in the hyperglycemic rats. Furthermore, it suggests that the increase in dopamine level of synaptosome might be due to the decrease in the release of dopaine in hyperglycemic state.

• 한국임상약학회지
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• 제8권2호
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• pp.139-142
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• 1998

The effects of MeOH extracts from 28 herbal medicines on monoamine oxidase (MAO) activity were investigated. MAO was purified from mouse brain and its activity was determined by fluoro-photometry using kynuramine as a substrate. Three MeOH extracts, Coptis japonica, Cinnamomum cassia and Poncirus trifoliate from the herbal medicines showed a strong inhibitory effect with less than $100\;{\mu}g/ml$ in their inhibitory amounts of $50\%$ ($IC_{50}$ values) on MAO activity. Four MeOH extracts including Evodia officinalis exhibited a mild inhibition of MAO activity with $100-200\;{\mu}g/ml$ in their $IC_{50}$ values.

• Archives of Pharmacal Research
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• 제28권4호
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• pp.400-404
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• 2005

Activity-guided fractionation of a hexane-soluble extract of the roots of Lithospermum erythrorhizon, using a mouse brain monoamine oxidase (MAO) inhibition assay, led to the isolation of two known naphthoquinones, acetylshikonin and shikonin, and a furylhydroquinone, shikonofuran E. These compounds were shown to inhibit MAO with $IC_{50}$ values of 10.0, 13.3, and $59.1 {\mu}M$, respectively. Although no specificity for MAO-A and MAO-B was shown by acetylshikonin and shikonin, a Lineweaver-Burk plot analysis indicated that the inhibition was competitive for both MAO-A and MAO-B activity.