Study On The Antioxidative Property Of Ferrocenyl-appended Flavone And Imidazo[1,2-a]quinoxaline

Ferrocene is widely applied in pharmaceutical chemistry and material chemistry.As bioactive natural products, flavone and aurone is structural isomer. There are many research reports about the antioxidative property of flavone and aurone, but the research about the antioxidative property of ferrocenyl-appended flavone and aurone is rare. Imidazo[1,2-a]quinoxaline is important nitrogenous heterocyclic compound, it have some biological activity, but the research about antioxidative property of imidazo[1,2-a]quinoxaline have not been report. Therefore, in this paper, we reserach the antioxidative property structure-activity relationship of ferrocenyl-appended flavone and imidazo[1,2-a]-quinoxaline. We evaluate the antioxidative property of ferrocenyl-appended flavone and imidazo[1,2-a]-quinoxaline by inhibiting2,2’-azobis(2-amidinopropane hydrochloride)(AAPH) induced oxidation of DNA and scavenging 2,2’-azinobis(3-ethylbenzothiazoline-6-sulfonate)cationic radical(ABTS+·), 2,2’-diphenyl-1-picrylhydrazyl radical(DPPH) and Galvinoxyl radical. In addition, we also test the oxidation poential and DNA binding constant of imidazo[1,2-a]-quinoxaline. The major contents of this paper is as the following:1. The synthesis and antioxidative property research of ferrocenyl-appended flavone and auroneIn this part, We synthesized 18 flavones and aurones, 9 structural isomers and 14 of them are ferrocenyl-appended flavones and aurones. The test results show that the original flavone and aurone have not antioxidative property. The flavone or aurone which have a hydroxy can inhibit AAPH induced oxidation of DNA and scavenge ABTS+·, it mean that the hydroxy is characteristic antioxidative substituent of flavones and aurones. For the ferrocenyl-appended flavones and aurones, all of them can inhibit AAPH induced oxidation of DNA and scaveng ABTS+·and DPPH racical great, it mean that ferrocenyl takes the antioxidative function in here and between ferrocenyl and hydroxy have synergistic effect, it can raise compound antioxidative property largely. In the test of inhibiting AAPH induced oxidation of DNA, the aurone show the activty better than flavone, but in the test of scavenging radical the result is opposite. Therefore, the antioxidative property of flavone and aurone have different strength in different oxidation system.2. Synthesis of imidazo[1,2-a]quinoxaline by Groebke multicomponent reaction and antioxidative property researchThrough two Groebke multicomponent reactions to synthesize 28 ferrocenyl or flavonyl appended imidazo[1,2-a]quinoxalines, we evaluate these compounds antioxidative property in above tests, in addition we also test oxidation potential and DNA binding constant. In the test of inhibiting AAPH induced oxidation of DNA,only the hydroxy or dimethylamino appended imidazo[1,2-a]quinoxalines can inhibit AAPH induced oxidation of DNA, and just introduction ferrocenyl or flavonyl to them can raise the compound ability of inhibiting AAPH induced oxidation of DNA.In the meanwhile, introduction ferrocenyl can rasie the compound ability of scavenging radical markedly, but the flavonyl have less effect. Also, the place of ferrocenyl in the structure of imidazo[1,2-a]quinoxaline have important effect to imidazo[1,2-a]quinoxaline antioxidative property. The oxidation potential tests prove that the ferrocenyl, hydroxy and dimethylamino both of them can reduce imidazo[1,2-a]quinoxaline oxidation potential, it is the reason why introduction these substituents can raise imidazo[1,2-a]quinoxaline antioxidative property.The test of DNA binding constant show that introduction ferrocenyl can decresae the bindingconstant between DNA and imidazo[1,2-a]quinoxaline, we think this is beneficial to compound make the antioxidative property.In summary, flavone, aurone and imidazo[1,2-a]quinoxaline all of them can through structral modification to become well antioxiadnt.