A comparative study of the antioxidant activities of three series of first- and second-generation PPI dendrimers (G1 and G2) functionalized by2- hydroxy-P-naphthoquinone

Abstract

 The work presented focuses on synthesizing molecules capable of blocking the deleterious effects of oxidative stress. Oxidative stress is caused by an imbalance between the pro-oxidant and antioxidant systems, with the former benefiting. It is implicated in numerous pathologies, either as a cause or a consequence. Oxidative stress is involved in chronic processes such as atherosclerosis and diabetes. The work presented in this article focuses firstly on the synthesis of a new class of first- and second-generation PPI dendrimers (G1 and G2) functionalized with 2-hydroxy-p-naphthoquinone, and secondly on the evaluation of their antioxidant activity. The dendrimeric molecules were obtained using an on-pot synthesis based on the Manich reaction. The molecules were characterised using the usual methods: 1H NMR, 13C NMR and dept, infrared (IR) and mass spectrometry. The antioxidant activity of the compounds was assessed by monitoring the scavenging kinetics of the DPPH (1,1-diphenyl-2-picryl-hydrazyl) radical. For the synthesis, three dendrimers, first- and second-generation PPI (G1 and G2) functionalised by 2-hydroxy-p- naphthoquinone, were synthesised (1a, 1b and 2). Concerning the antioxidant tests of the molecules synthesised, it can be seen that all the dendrimers have the ability to trap free radicals and that the values for the percentages of DPPH reduced are very different. A comparison of the percentages of DPPH reduced showed that P1b <P2< P1a. A study of antioxidant activity using the DPPH method revealed that the dendrimers synthesised have antioxidant activity. All the results obtained were interesting.