• Archives of Pharmacal Research
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• v.13 no.2
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• pp.132-135
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• 1990

Polyhydroxystilbenes including resveratrol were reported to competitively inhibit monoamine oxidase-A-without structural relation with substrates and cynthetic inhibitors for the enzyme. We attempt to explore a plausible mechanism for their inhibitory activity on MAO-A. All the polyhydroxystilbenes tested showed the antioxidant activity on liver homogenate. Furthermore, the antioxidant activity turned out to closely correlate with the MAO-A inhibitory activity.

• Applied Chemistry for Engineering
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• v.24 no.1
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• pp.55-61
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• 2013

Heterogeneous metallocene catalysts supported on montmorillonite (MMT), [$Cp_2ZrCl_2$/MMT, $Cp_2ZrCl_2$/MAO/MMT, and $Cp_2ZrCl_2$ + MAO/MMT], were prepared with three different methods of immobilization and tested for ethylene polymerization. The heterogeneous catalysts immobilized on organo clay (30B-MMT) showed the higher metal loading and polymerization activity than those immobilized on natural clay $Na^+-MMT$. These results suggest that the hydroxyl groups of organo clay interlayers react with the MAO and catalyst through the chemical bond. The metallocene catalyst supported directly on MMT showed lower activity for ethylene polymerization compared to the homogeneous systems, while MMT/MAO/$Cp_2ZrCl_2$, catalysts treated with MAO before impregnation, showed a higher activity. The polymers obtained from MMT-supported catalysts have higher melting point, molecular weight and molecular weight distributions than those of homogeneous catalysts. The polymer particles with increasing significant size. Ethylene polymerization over 30B-MMT/MAO/$Cp_2ZrCl_2$ catalyst was also performed varying the process variables to optimize the process conditions.

• Korean Journal of Pharmacognosy
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• v.30 no.2
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• pp.145-150
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• 1999

To explain the theory of KIMI which is the theory of therapeutics in oriental medicine, monoamine oxidase(MAO) activities were measured in the brain and liver of mice which were orally administered oriental medicinal herbs which were classified into cold and hot drugs. Rheum palmatum, Anemarrhena asphodeloides, Gardenia jasminoides, Scutellaria baicalensis and Coptis japonica were considered as the cold drugs and Zingiber officinale, Aconitum carmichaeli, Asiasarum sieboldi, Evodia officinalis and Cinnamomum cassia were included in the hot drugs. The effects of cold and hot drugs on in vitro enzyme activities were measured and compared with the in vivo effects. Serotonin is important neurotransmetter involved in the control of body temperature. The MAO plays a central role in the metabolism of many neurotransmetter monoamines including serotonin. MAO is a flavoprotein found exclusively in the mitochondrial outer membrane, occuring in the MAO-A and MAO-B subtypes. MAO-A deaminates serotonin and noradrenaline, whereas MAO-B prefers phenylethylamine and benzylamine as substrates. Coptis japonica and Aconitum carmichaeli elevated the in vivo MAO activities and especialy, in vivo MAO-B activities were significantly increased. In vitro MAO-A activities were increased by hot drugs, whereas the in vitro MAO-B activities were inhibited. Cold drugs inhibited both enzyme activities in vitro.

• Journal of Microbiology and Biotechnology
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• v.25 no.9
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• pp.1425-1428
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• 2015

Monoamine oxidase (MAO) is found in most cell types and catalyzes the oxidation of monoamines. Three anithiactins (A-C, modified 2-phenylthiazoles) isolated from Streptomyces sp. were tested for inhibitory activity of two isoforms, MAO-A and MAO-B. Anithiactin A was effective and selective for the inhibition of MAO-A, with an IC₅₀ value of 13.0 μM; however, it was not effective for the inhibition of MAO-B. Anithiactins B and C were weaker inhibitors for MAO-A and MAO-B. Anithiactin A was a reversible and competitive inhibitor for MAO-A with a K_i value of 1.84 μM. The hydrophobic methyl substituent in anithiactin A may play an important role in the inhibition of MAO-A. It is suggested that anithiactin A is a selective reversible inhibitor for MAO-A, with moderate potency, and can be considered a new potential lead compound for further development of novel reversible inhibitors for MAO-A.

• Nutrition Research and Practice
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• v.18 no.1
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• pp.110-118
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• 2024

BACKGROUND/OBJECTIVES: Depression and anxiety are common mental health problems. Anthocyanins from berries might have an inhibitory effect on monoamine oxidase (MAO) enzymes and alleviate various mood and anxiety symptoms. This study examined the effects of a daily supplement of an anthocyanin-rich product on mental health problems. SUBJECTS/METHODS: This study was a secondary analysis from a randomized, 6-week, open-label trial in 300 healthy participants aged 18-60 years who consumed 1 or 2 servings of anthocyanin-rich mulberry milk daily. The General Health Questionnaire-28 (GHQ-28) and Hospital Anxiety and Depression Scale (HADS) were used to monitor mental health problems. In addition, the saliva activity levels of MAO-A, MAO-B, and cortisol were examined at the baseline and after 6 weeks. RESULTS: The total scores of the GHQ-28 and HADS and all their subscales decreased in both groups (all P < 0.05). The cortisol, MAO-A, and MAO-B activities decreased significantly (all P < 0.05), but there were no significant differences between the groups (all P > 0.05). Significant correlations were noted between the decreased activity level of MAO-A enzyme and decreased scores from the GHQ-28 somatic subscale and the HADS depression subscale (all P < 0.05). CONCLUSIONS: Daily consumption of anthocyanin-rich mulberry milk possibly improves mental health problems by reducing depressive and anxiety symptoms in the working population. The suppression of MAO-A activity is a possible underlying mechanism.

• Biomolecules & Therapeutics
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• v.21 no.3
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• pp.234-240
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• 2013

Monoamine oxidase inhibitors (MAOI) have been widely used as antidepressants. Recently, there has been renewed interest in MAO inhibitors. The activity-guided fractionation of extracts from Angelica keiskei Koidzumi (A. keiskei K.) led to the isolation of two prenylated chalcones, xanthoangelol and 4-hydroxyderricin and a flavonoid, cynaroside. These three isolated compounds are the major active ingredients of A. keiskei K. to inhibit the MAOs and DBH activities. Xanthoangelol is a nonselective MAO inhibitor, and a potent dopamine ${\beta}$-hydroxylase (DBH) inhibitor. $IC_{50}$ values of xanthoangelol to MAO-A and MAO-B were calculated to be 43.4 ${\mu}M$, and 43.9 ${\mu}M$. These values were very similar to iproniazid, which is a nonselective MAO inhibitor used as a drug against depression. The $IC_{50}$ values of iproniazid were 37 ${\mu}M$, and 42.5 ${\mu}M$ in our parallel examination. Moreover, $IC_{50}$ value of xanthoangelol to DBH was calculated 0.52 ${\mu}M$. 4-Hydroxyderricin is a potent selective MAO-B inhibitor and also mildly inhibits DBH activity. The $IC_{50}$ value of 4-hydroxyderricin to MAO-B was calculated to be 3.43 ${\mu}M$ and this value was higher than that of deprenyl (0.046 ${\mu}M$) used as a positive control for selective MAO-B inhibitor in our test. Cynaroside is a most potent DBH inhibitor. The $IC_{50}$ value of cynaroside to DBH was calculated at 0.0410 ${\mu}M$. Results of this study suggest that the two prenylated chalcones, xanthoangelol and 4-hydroxyderricin isolated from A. keiskei K., are expected for potent candidates for development of combined antidepressant drug. A. keiskei K. will be an excellent new bio-functional food material that has the combined antidepressant effect.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.188-188
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• 1998

Extracts of 24 edible vegetables were tested concerning their action on in vitro inhibition on dopamine ${\beta}$-hydroxylase (DBH) and monoamine oxidase (MAO). All vegetables were purchased in Korean market and their common names were kept. Radish sprouts, ‘kkoch-na-mul’, ‘chong-gyong-chae’, ragwort, applemint showed strong DBH inhibitory effect when tyramine and crude bovine adrenal DBH were used as substrate and enzyme, respectively. ‘Cham-chwi’(Aster scaber), kale, ‘cham-na-mul’(Pimpinella brachycarpa), leek were found to have MAO-A inhibitory effect with serotonin and crude rat brain MAO-A. Lettuce, ‘chong-gyong-chae’, radish sprouts, beet leaves were found to have MAO-B inhibitory effect with benzyl amine and crude rat liver MAO-B.

• Macromolecular Research
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• v.12 no.4
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• pp.336-341
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• 2004

A new type of cross-linked methylaluminoxane (MAO)-supported cocatalyst has been prepared by the reaction of a soluble MAO and a cross-liking agent such as an aromatic diamine compound. The cross-linked MAO-supported cocatalyst was used for the polymerization of ethylene in the presence of bis(n-butylcyclopentadienyl) zirconium dichloride, (n-BuCp)$_2$ZrCl$_2$. The catalyst activity of (n-BuCp)$_2$ZrCl$_2$ cocatalyzed with the new supported cocatalyst was higher than that of the commercial silica-supported MAO (SMAO) cocatalyst. The molecular weight and the bulk density of the polyethylene produced by using the new supported cocatalyst were slightly higher than those of polyethylene synthesized using commercial SMAO. The resulting polyethylene particles possess spherical morphologies with very few fine particles.

• 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.

• Archives of Pharmacal Research
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• v.29 no.12
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• pp.1119-1124
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• 2006

The methanol extract from the aerial parts of Dictamnus albus was active in inhibiting monoamine oxidase (MAO) from the mouse brain. Activity-guided fractionation led to the isolation of four known coumarins, 7-(6'R-hydroxy-3', 7'-dimethyl-2'E, 7'-octadienyloxy) coumarin (1), auraptene (2), umbelliferone (3), and xanthotoxin (4), as active compounds along with an inactive alkaloid, skimmianine (5). Compounds 1 and 2 inhibited MAO activity in a concentration-dependent manner with $IC_{50}$ values of 0.7 and $1.7\;{\mu}M$, respectively. Compounds 1 and 2 showed a slight and potently selective inhibitory effect against MAO-B ($IC_{50}\;0.5\;and\;0.6\;{\mu}M,\;respectively$) compared to MAO-A ($IC_{50}\;1.3\;and\;34.6\;{\mu}M,\;respectively$). According to kinetic analyses derived by Lineweaver-Burk reciprocal plots, compounds 1 and 2 exhibited a competitive inhibition to MAO-B.