Résumé:
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
