The Synthesis And Applied Of Lipoxygenase Inhibitor Phloretin

This topic mainly was engaged in the synthesis of lipoxygenase inhibitor---- phloretin, using the new catalyst. and the structure of the intermediate 3-(4-Methoxyphenyl)propionic acid, ester were also be synthesized.The preparation of 3-(4-Methoxyphenyl)propionic acid from propanedioic acid diethyl ester and the 4- methoxy phenylmethyl chlorine by alkylation, hydrolysis, decarboxylation has been investigated. The optimum reaction condition was: alkylation 80℃, 10 h, hydrolysis 120-140℃, decarboxylation 120-140℃, and the yiled was 62.88%; Then the ester was synthesized by acylation and esterification and the optimum reaction condition was: 4 h, 75℃, 1,3,5-trihydroxybenzene:3-(4-Methoxyphenyl) propionic acid (mol)=1:3.2, pyridine 15mL, and the yield was 98.43%; The intermediate was identified by melt point ,UV and IR. The final reaction yield of Fries rearrangement was 13.64% and the product was identified as phloretin by Rf value, melt point , UV, IR and 1H-NMR.In this thesis, we mainly discussed the extraction of lipoxygenase from soybean. The experiment results show that the total enzyme activity 7.03×107U/10g(defatted soybean flour) obtained by water–leaching is the highest with corresponding specific enzyme activity 9.02×105U/mL(enzyme preparation). Specific activity of LOX 9.26×107U/g(powdered enzyme) obtained by alkali-dissolving and acid-leaching followed by two salting-out steps is the highest of all. And the soybean lipoxygenase was determinded by using spectrophotometric method.In this paper, we investigated the effect of eight selected flavonoids [flavanonol ( hesperidin and liquiritigenin); chalcone ( isoliquiritigenin and phlorizin); isoflavone ( daidzein and formononetin);flavonol(quercetin and rutin)] variable structure on lipoxygenase using linoleic acid as substrate. The results show that flavonoids can strongly inhibit the lipoxygenase . Besides hesperidin ,all other flavonoids'inhibition are enhanced following with their contents. From the experiment results, we know rutin turned to be the most potent inhibitor of the lipoxygenase with an IC50 of 3.84×10-3μg/mL followed by quercetin (8.92×10-3μg/mL), phloritin (3.18×10-2μg/mL), daidzein (6.57×10-2μg/mL), isoliquiritigenin (6.96×10-2μg/mL), formononetin (7.39×10-2μg/mL ), liquiritigenin and(0.4μg/mL ,and hesperidin (0.47μg/mL)has the highest inhibition of 45.1 %。...