Inhibition of human monoamine oxidase (MAO) enzymes by some Thai medicinal plant extracts

ฤทธิ์บับยั้งเอนไซม์โมโนเอมีนออกซิเดสของมนุษย์จากพืชสมุนไพรไทยบางชนิด

Name: Sopa Ninted

LCSH: Enzymes

Classification :.DDC: 547.758

LCSH: Enzyme inhibitors

Abstract: Chronic neurological cause the high morbidity and mortality of current population in the world. In addition, the number of patients with neurological disorder such as Alzheimer’s and Parkinson’s disease are becoming increase worldwide. It has been reported that one common incidence of these disease is the improper function of the brain monoamine oxidase (MAO) isoform A (MAO-A) and B (MAO-B). Normally, these enzymes metabolize monoamine neurotransmitters, including the serotonin or 5-hydroxytryptamine (5-HT) for MAO-A, both dopamine (DA) and norepinephrine (NE) for MAO-B. High enzymatic activity of either MAO-A or MAO-B could lead to the low level of such neurotransmitters and result in neurological disorders. Nowadays, various medicinal plants are widely used to treatment many diseases. This study aimed to screen Thai traditional herbs, commonly used in Thailand, for their abilities to inhibit MAO enzymes. The activity of MAO enzymes was determined ABTS assay that coupling assay and fluorometric assay as a direct MAO substrate fluorescence. Thus, for reduce affected the interpretation of a MAO assay system used fluorometric assay for detect activity of MAOs. The fluorometric assay upon using kynuramine as a probe substrate and measuring the change in rate of 4-hydroxyquinoline product generating by fluorescence spectrophotometry. The result shown that Atractylodes lancea (Thunb) DC. Extract exhibited highest inhibitory activity against MAO exzymes with an IC50 value of 42.74 ug/ml for hMAO-A, and an IC50 value of 20.25 ug/ml for hMAO-B, respectively. The A. Lancea crude extract for further separated based on activity-guided isolation and characterized with various purification step such as liquid-liquid extraction to search for candidate constituents which isolated different polarity fractions, including hexane, ethyl acetate, and water fractions. The results suggested that the active constituents in A.lancea could inhibit hMAO enzymes in time-dependent manner. This results also suggested that the constituents in hexane fraction could inhibit hMAO-A with time-dependent manner with an IC50 value of 18.44+-0.83 ug/ml but reversible inhibition with MAO-B with an IC50 value of 15.42+-1.18 ug/ml. For further investigated characterize by HPLC sub-fraction from hexane 1.1 obtained by repeated run of TLC then scratched the silica bead and dissolved to extract the constituents in solvent has a chromatogram similarly B-eudesmol compound investigated from retention time. For ensues the active constituents in sub-fraction hexane 1.1 subsequently characterized by NMR spectroscopy showed that was B-eudesmol. Moreover, structural-function relationship of B-eudesmol with MAO-A and MAO-B indicated the hydrophobic interaction between specific residue in MAOs active site, resulting in low inhibitory activity. Therefore, isolated B-eudesmol from A. lancea have effectively inhibited MAO-A and MAO-B enzymes associated candidate constituents drug therapy for further application to cure neurodegenerative diseases.

Burapha University. Library

Address: CHONBURI

Email: buulibrary@buu.ac.th

Name: Songklod Sarapusit

Role: Principal advisor

Created: 2020

Modified: 2021-06-17

Issued: 2021-06-17

วิทยานิพนธ์/Thesis

application/pdf

CallNumber: Th 547.758 So712I

eng

DegreeName: Master of Science

Level: Master's Degree

Descipline: Biochemistry

Grantor: Burapha University

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