• Journal of Food Hygiene and Safety
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• v.10 no.4
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• pp.279-282
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• 1995

Eight natural or semistynthesized monoterpenes were examined for their effects in rat brain monoamine oxidase(MAO) using benzylamine as substrate. Thujone and 3-carene were found to have the inhibition effects on rat brain MAQ activity, 38% and 95% inhibition at 103M respectively. The kinetic study on 3-carene, the most potent inhibitive type. But (+) pulegon and (-) isopulegon was found to activate MAO slightly.

• YAKHAK HOEJI
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• v.27 no.4
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• pp.321-329
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• 1983

The review characterized active site(s) of MAO with respect to metal ions, hydrophobic and polar region, sulfhydryl group and flavin moiety. The mechanism of inhibition was dealt with three representative types of inhibitors; phenylcyclopropylamines, acetylenic amines, and hydrazines. Multiple forms of MAO was shortly described in relation to their selective inhibition. 84 reference were cited.

• Korean Journal of Pharmacognosy
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• v.37 no.4 s.147
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• pp.320-323
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• 2006

The effects of evodiamine on monoamine oxidase (MAO) activity were investigated. MAO was purified from mouse brain and the $K_m\;and\;V_{max}$ values of MAO were $78.5{\pm}5.28{\mu}M$ and $0.68{\pm}0.07$ nmol/min/mg protein, respectively (n=4). Evodiamine at $30-120{\mu}M$ showed an inhibitory effect on MAO activity using a substrate kynuramine with an $IC_{50}$ value of $104.2{\mu}M$ (n=4). Evodiamine also exhibited a non-competitive inhibition on MAO. The $K_i$ value for evodiamine was $72.5{\pm}10.8{\mu}M$ (n=4). These results suggest that evodiamine partially contributes to the regulation of monoamine content.

• The Journal of the Korean life insurance medical association
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• v.1 no.1
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• pp.84-87
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• 1984

1. Effect of bretylium on the pressor response of the whole and spinal rabbits to tyramine was observed in conditions of monoamine oxidase inhibition brought about by catron administration. 2. Bretylium increased the prossor response to tyramine in the whole and spinal rabbits. 3. Bretylium failed to increase the tyramine effect if bretylium was given after administration of catron, a monoamine oxidase inhibitor. Actually the tyramine effect was decreased by bretylium in this situation. 4. The increase of the tyramine effect by bretylium will be due to its monoamine oxidase inhibitory property, and the decrease of the tyramine effect will be due to its adrenergic neurone b1coking property.

• Journal of Microbiology and Biotechnology
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• v.27 no.2
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• pp.316-320
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• 2017

Alternariol monomethyl ether (AME), a dibenzopyrone derivative, was isolated from Alternaria brassicae along with altertoxin II (ATX-II). The compounds were tested for the inhibitory activity of monoamine oxidase (MAO), which catalyzes neurotransmitting monoamines. AME was found to be a highly potent and selective inhibitor of human MAO-A with an $IC_{50}$ value of $1.71{\mu}M$; however, it was found to be ineffective for MAO-B inhibition. ATX-II was not effective for the inhibition of either MAO-A or MAO-B. The inhibition of MAO-A using AME was apparently instantaneous. MAO-A activity was almost completely recovered after the dilution of the inhibited enzyme with an excess amount of AME, suggesting AME is a reversible inhibitor. AME showed mixed inhibition for MAO-A in Lineweaver-Burk plots with a $K_i$ value of $0.34{\mu}M$. The findings of this study suggest that microbial metabolites and dibenzopyrone could be potent MAO inhibitors. In addition, AME could be a useful lead compound for developing reversible MAO-A inhibitors to treat depression, Parkinson's disease, and Alzheimer's disease.

• Biomolecules & Therapeutics
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• v.20 no.2
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• pp.214-219
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• 2012

This research was designed to determine what components of Gardenia jasminoides play a major role in inhibiting the enzymes related antidepressant activity of this plant. In our previous research, the ethyl acetate fraction of G. jasminosides fruits inhibited the activities of both monoamine oxidase-A (MAO-A) and monoamine oxidase-B (MAO-B), and oral administration of the ethanolic extract slightly increased serotonin concentrations in the brain tissues of rats and decreased MAO-B activity. In addition, we found through in vitro screening test that the ethyl acetate fraction showed modest inhibitory activity on dopamine-${\beta}$ hydroxylase (DBH). The bioassay-guided fractionation led to the isolation of five bio-active compounds, protocatechuic acid (1), geniposide (2), 6'-O-trans-p-coumaroylgeniposide (3), 3,5-dihydroxy-1,7-bis(4-hydroxyphenyl) heptanes (4), and ursolic acid (5), from the ethyl acetate fraction of G. jasminoides fruits. The isolated compounds showed different inhibitory potentials against MAO-A, -B, and DBH. Protocatechuic acid showed potent inhibition against MAO-B ($IC_{50}$ $300{\mu}mol/L$) and DBH ($334{\mu}mol/L$), exhibiting weak MAO-A inhibition (2.41 mmol/L). Two iridoid glycosides, geniposide ($223{\mu}mol/L$) and 6'-O-trans-p-coumaroylgeniposide ($127{\mu}mol/L$), were selective MAO-B inhibitor. Especially, 6'-O-trans-p-coumaroylgeniposide exhibited more selective MAO-B inhibition than deprenyl, well-known MAO-B inhibitor for the treatment of early-stage Parkinson's disease. The inhibitory activity of 3,5-dihydroxy-1,7-bis (4-hydroxyphenyl) heptane was strong for MAO-B ($196{\mu}mol/L$), modest for MAO-A ($400{\mu}mol/L$), and weak for DBH ($941{\mu}mol/L$). Ursolic acid exhibited significant inhibition of DBH ($214{\mu}mol/L$), weak inhibition of MAO-B ($780{\mu}mol/L$), and no inhibition against MAO-A. Consequently, G. jasminoides fruits are considerable for development of biofunctional food materials for the combination treatment of depression and neurodegenerative disorders.

• Korean Journal of Pharmacognosy
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• v.29 no.4
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• pp.271-276
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• 1998

The inhibitory effects of MeOH extracts of 100 medicinal herbs on monoamine oxidase (MAO) activity were investigated. MAO was purified from mouse brain and its activity was determined by fluorospectrophotomer using kynuramine as a substrate. Nine kinds of MeOH extracts of herbs including Artemisia iwayomogi showed a mild inhibitory effect with ${100}-{200}\;{\mu}/ml$ in their $IC_{50}$ values on MAO activity. Seventeen MeOH extracts including Juglans mandshurica exhibited a weak inhibition of MAO activity with ${200}-{300}\;{\mu}/ml$ in their $IC_{50}$ values.

• Natural Product Sciences
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• v.6 no.2
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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.

• Archives of Pharmacal Research
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• v.28 no.4
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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.

• Archives of Pharmacal Research
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• v.7 no.1
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• pp.65-68
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• 1984

Mechanism of the monoamine oxidase inhibition by tranylcypromine was studied in relation to its metabolism to reactive apecies. A metabolic study performed to collect general biotransformation pathway in rats provided GC/MS evidence for the detection of two new metabolites, N-acetyl and hydroxylated N-acetyltranylacypromine.