The Desigh、Synthesis And Application Of The Novel Monoamine Oxidase Probe Based On Fluorescein

Fluorescein was widely used in the biological and biomedical analysis, due to high extinction coefficient, high fluorescence quantum yield in aqueous solution, its excitation wavelength and emission wavelength in the visible range and innoxiousness. Fluorescein contains multiple active groups, in order to improve the hydrophilicity and lipid-soluble, chemical modification is applied to the active group of fluorescein, thus to obtain the fluorescein derivative which is more suitable for the testing in biological bodies.We synthesized a new novel of fluorogenic probe in this paper. It has 1,2,3,6-tetrahydropyridin group as the substrate of the monoamine oxidase, and a fluorescein as a fluroscent indicator, the monoamine oxidase fluorescent probe was designed and synthesized. The probe has no fluorescence itself because the phenolic hydroxy on fluorescein is substitued by 1,2,3,6-tetrahydropyridin group. When the probe reacted with monoamine oxidase, the 1,2,3,6-tetrahydropyridin group was oxidation to pyridine salt and rapid hydrolysis into 1-methyl -2,3-dihydropyridin-4(1H)-one and 2-(3-hydroxy-6-methoxy-9H-xanthen-9-yl)benzoic acid which was followed by oxidation to 6-methyl-fluorescein with strongly fluorescent, therefore, the activities of MAOs could be easily detected by comparing the intensity of the fluorescence before and after the reaction.Subsequently, we detected a series of fluorescence performance of the probes and study for the enzyme reaction the kinetics. The result shows that the probes have good detection effectively for monoamine oxidase, and good selectivity on monoamine oxidase B.Then, the probe 1 was chosed because of its good selectivity and prepared by structural modification in order to change the lipophilicit and improve the penetration ability of the probe into the cells,which was making preparation for the cell fluorescence imaging.In conclusion, We reported here the design, synthesis a new fluorogenic probes which utilized a 4-Phenoxy-1-methyl-1,2,3,6-tetrahydropyridine R-carbon oxidation-hydrolysis mechanism to detect the activities of MAOs in vitro directly. and the results showed that our probes were able to detect MAOs in simple, effective and sensitive for MAO-B.