• 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.

• 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.

• Archives of Pharmacal Research
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• v.28 no.12
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• pp.1324-1327
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• 2005

A methylene chloride soluble fraction of the fruits of Cudrania tricuspidata significantly inhibited the mouse brain monoamine oxidase (MAO). Three known prenylated isoflavones were isolated and identified by activity-guided fractionation. Gancaonin A (1), 4'-O-methylalpinumisoflavone (2), and alpinumisoflavone (3) inhibited MAO activity in a concentration-dependent manner with $IC_{50}$ values of 19.4, 23.9, and 25.8 $\mu$M, respectively. Of these, gancaonin A (1) showed a selective and potent inhibitory effect against MAO-B ($IC_{50}$ 0.8 $\mu$M) than MAO-A ($IC_{50}$ >800 $\mu$M). The kinetic analysis using Lineweaver-Burk plots indicated that gancaonin A (1) competitively inhibited MAO-B.

• Preventive Nutrition and Food Science
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• v.8 no.2
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• pp.141-144
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• 2003

Ixeris dentata Nakai (Compositae) is a perennial herb which has been used as a folk medicine for treating diabetes and gastroenteric troubles in Korea. Active compounds were isolated from the aerial parts of Ixeris dentata through the bioassay-guided fractionation and isolation method evaluated for inhibition of monoamine oxidase (MAO) in vitro. The compounds were identified as 5,7,3',4'-tetrahydroxyflavone (1) and 5,7,3',4'- tetrahydroxyflavone 7-glucoside (2), based on physical and spectroscopic characteristics. Compounds 1 and 2 showed a selective inhibition of type B MAO (MAO-B) activity, with IC/sub 50/ values of 15.3 μM and 36.4 μM, respectively, but did not inhibit type A MAO (MAO-A) activity.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.3
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• pp.458-463
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• 2002

This present study was designed to screen medicinal plants for the treatment of brain diseases such as Parkinson's disease or Alzheimer's disease. The inhibitory activity of monoamine oxidase B (MAO-B) was investigated in the water extracts of 56 species traditional medicines. Among the tested medicinal plants, E. lathyris, R. palmatum, F. rhynchonphylla, E. caryophyllata, E. pekinensis and H. syriacus were showed the strong inhibitory activity against MAO-B. Therefore, MAO-B inhibitory activity of 6 traditional medicine extracts in the different concentration (2.5, 6.5 and 12.5 ㎍/ml) was determined. The inhibitory effect of MAO-B was detected with dose dependently in 6 traditional plants extracts. E. caryophyllata and R. palmatum were showed the highest inhibitory activity, the MAO-B inhibitory activity at 2.5㎍ of herbal extract being 58% and 52%, respectively. The water extracts of 6 species were tested on antioxidant activity using radical scavenging effects against ABTS/sup +/. The water extracts of R. palmatum, E. caryphyllata, E. pekinensis and H. syriacus were showed strong antioxidant capacity at 20 ㎍ concentration. Among the 56 medicinal plants investigated, the water extracts of R. palmatum and E. caryphyllata were showed significant antioxidant capacity and MAO-B inhibiory activity. Therefore, R. palmatum and E. caryphyllata are expected to ameliorate the clinical symptoms in Parkinson's disease due to significant MAO-B inhibition and radical scavenging effect.

• Korean Journal of Food Science and Technology
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• v.29 no.1
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• pp.156-160
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• 1997

The monoamine oxidase (MAO, EC 1.4.3.4) plays a central role in the metabolism of many amines including the neurotransmitter monoamines. 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 much better than phenethylamine (PEA) or benzylamine (BA), and is preferentially inhibited by clorgyline, whereas MAO-B prefers PEA and BA as substrates and is preferentially inhibited by deprenyl. MAO inhibitors were among the first drugs used in the treatment of depression, and it is known to be the inhibition of MAO-A which is important for the antidepressant effect of MAO inhibitors. For the purpose of evaluating MAO inhibitory activities from natural resources, three kinds of edible mushrooms were screened by tracing the inhibitory activities against rat brain mitochondrial MAO-A, utilizing serotonin as a substrate and rat liver mitochondrial MAO-B utilizing benzylamine as a substrate. Among the tested mushrooms, Ganoderma lucidium and Lentinus edodes showed the weak inhibitory activities against MAO-B.

• Korean Journal of Food Science and Technology
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• v.37 no.1
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• pp.95-102
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• 2005

Effects of Morus alba fruit extracts on monoamine oxidase (MAO) activity were examined in rats during and after physical exercise. Oral administration of M. alba extract (0.3 g/kg body weight) significantly increased brain MAO-A activity but decreased liver MAO-B activity when they were measured using serotonin and benzylamine as substrates. Type of physical exercises had significant effect on MAO activity. Brain MAO-A activity markedly decreased with physical activity-related stress compared to normal group, whereas Liver MAO-B activity increased up to 60 min after exercise. Lactate dehydrogenase (LDH) activity and lactate concentration in blood, clinical indices of physical exercise activities, were also determined for correlation to MAO activities. MAO-A activity of rats subjected to oral administration of M. alba extract and physical exercise increased whereas MAO-B and LDH activities, and lactate level decreased, All indices eventually recovered normal levels, These results suggest M. alba may increase capability of physical activities by modulating MAO activities during exercise.

• Journal of Ginseng Research
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• v.18 no.2
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• pp.118-121
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• 1994

Alcohol and acetaldehyde concentrations were measured in the blood and brain of rats which were treated with 20% alcohol (control group) or co-administered 20% alcohol with ginseng extract residue roasted (test group). There was no change in blood alcohol concentration between control and test group. However, the brain alcohol concentration was lowered in the test group which was treated for seven days. The concentration of aldehyde in the brain and blood was lowered in the test group. The activities of monoamine oxidase b in various regions of brain were recovered to normal group in the test groups. However, the Quantities of naloxone binding receptors were not changed by ginseng extract residue roasted.

• 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.

• Journal of the Korean Society of Tobacco Science
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• v.18 no.2
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• pp.160-169
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• 1996

Effect of cigarette smoke exposure on 1-methyl-4-phpnyl-1,2,3,6-tetrahydro-pyidine (Mm)-induced neurotoxicity was investigated in C57BL6 mice. Cigarette smoke exposure of mice to the mainstream smoke generated from 15 cigarettes for 10 mins per day, 5 days per week, for fi weeks, effectively attenuated the decline both in the level of striatal dopamine and the number of brrosine hydros:ylase-positive ceils in the brain caused by MPTP treahent. Exposure to cigarette smoke significantly decreased monoamine oxidate B activity in the cerebral cortex and cerebellum. The activity of brain antioxidant enzymes such as catalase, glutathione peroxidase, and Cu, Zn-superoxide dismutase, was not changed by cigarette smoke exposure or MPTP treatment. Sulfhydryl compounds content in all brain regions except for the striatum was uniquely increased by MPTP treatment, however, such an effect of MPTP was not observed in mice exposed to cigarette smoke. These results suggest that cigarette smoke exposure inhibits MPTP-induced neurotoxicity without influencing free radical metabolism in the brain of mice. This protective effect of cigarette smoke seems to be closely related with the decreased activity of brain monoamine oxidase H. Key words : cigarette smoke exposure, dopamine, monoamine oxidase B, antioxidant enzywles, MPTP.