Les interactions fonctionnelles des flavonoïdes de l’extrait butanolique de la plante Heliotropium undulatum vis-à-vis des mécanismes de l’hépatoxicité de l’hydrazine chez le rat.

Abstract

The work presented in this thesis contributes to the valorization of the aerial part of an endemic plant collected from the Algerian Sahara, Heliotropium undulatum Vahl (the family Boraginaceae). This study was conducted to evaluate the antioxidant and antiinflammatory activities of n-BuOH extracts of stems and leaves of H. undulatum using a rat- hydrazine model. In vitro studies (DPPH°, Chelation, FRAP, °OH) reveal that the n-BuOH extract of leaves has an antioxidant property. In vivo studies have also shown that the n-BuOH extract of 200 mg/kg leaves has demonstrated hepatoprotective activity by preserving liver function, modulating CYP2E1, neutralizing hepatic oxidative stress, and providing intra- mitochondrial redox status exhibited during treatment with hydrazine (300 mg/kg). The antiinflammatory activity was better pronounced by the n-BuOH extract of the stems, the demonstration of which is carried out using various in vitro tests (denaturation of albumin, HRBC, NO° scavenger). The study of modulatory pathways (hepatic carbonyl proteins, MPO, levels of NO, IL-ip and TNF-a) confirmed the in vivo anti-inflammatory potential of the n- BuOH extract of stems. The set of concomitant antioxidant and anti-inflammatory mechanisms characterizing the two extracts of Heliotropiuin undulatum is correlated with the qualitative and quantitative nature of the phenolic acids and flavonoids revealed via HPLC- MASS analysis and with the synergetic effect of all the phytoconstituents contained in this plant